Title of Invention	A SELECTIVE HYDROGENATION CATALYST AND METHODS OF MAKING AND USING SAME
Abstract	A method for producing a selective hydrogenation catalyst for hydrogenating a highly unsaturated hydrocarbon to an unsaturated hydrocarbon comprising contacting an inorganic catalyst support with a chlorine-containing compound to form a chlorided catalyst support and adding palladium to the chlorided catalyst support to form a supported-palladium composition. A selective hydrogenation catalyst for hydrogenating a highly unsaturated hydrocarbon to an unsaturated hydrocarbon formed by the method comprising contacting an inorganic catalyst support with a chlorine-containing compound to form a chlorided catalyst support and adding palladium to the chloride catalyst support to form a supported-palladium composition. A method of selectively hydrogenating a highly unsaturated hydrocarbon to an unsaturated hydrocarbon comprising contacting the highly unsaturated hydrocarbon with a selective hydrogenation catalyst composition produced by contacting an inorganic catalyst support with a chlorine-containing compound to form a chlorided catalyst support and adding palladium to the chlorided catalyst support to form a supported-palladium composition.

Title of Invention

A SELECTIVE HYDROGENATION CATALYST AND METHODS OF MAKING AND USING SAME

Abstract

A method for producing a selective hydrogenation catalyst for hydrogenating a highly unsaturated hydrocarbon to an unsaturated hydrocarbon comprising contacting an inorganic catalyst support with a chlorine-containing compound to form a chlorided catalyst support and adding palladium to the chlorided catalyst support to form a supported-palladium composition. A selective hydrogenation catalyst for hydrogenating a highly unsaturated hydrocarbon to an unsaturated hydrocarbon formed by the method comprising contacting an inorganic catalyst support with a chlorine-containing compound to form a chlorided catalyst support and adding palladium to the chloride catalyst support to form a supported-palladium composition. A method of selectively hydrogenating a highly unsaturated hydrocarbon to an unsaturated hydrocarbon comprising contacting the highly unsaturated hydrocarbon with a selective hydrogenation catalyst composition produced by contacting an inorganic catalyst support with a chlorine-containing compound to form a chlorided catalyst support and adding palladium to the chlorided catalyst support to form a supported-palladium composition.

Full Text	A SELECTIVE HYDROGENATION CATALYST AND METHODS OF MAKING AND USING SAME CROSS-REFERENCE TO RELATED APPLICATIONS The present application claims priority under 35 U.S.C. § 119(e) to U.S. provisional patent application number 60/702,745 entitled "A Selective Hydrogenation Catalyst and Methods of Making and Using Same" and filed on July 27, 2005. Furthermore, the subject matter of this application is related to the subject matter of U.S. provisional patent application number 60/388,307 entitled "Hydrogenation Palladium-Silver Catalyst and Methods" and filed on June 14, 2002, U.S. patent application number 10/457,635 entitled "Hydrogenation Palladium-Silver Catalyst and Methods" and filed on June 9, 20Q3, and U.S. patent application number 10/741,800 entitled '"Methods of Making and Using a Selective Hydrogenation Catalyst" and filed on December 19, 2003. Each of the foregoing applications is hereby incorporated by reference herein in its entirety. FIELD OF THE INVENTION The present invention relates to the production of unsaturated hydrocarbons, and more particularly to a selective hydrogenation catalyst and methods of making and using the same to selectively hydrogenate highly unsaturated hydrocarbons. BACKGROUND OF THE INVENTION Unsaturated hydrocarbons such as ethylene and propylene are often loved as feedstock’s in preparing value added chemicals and polymers. Unsaturated hydrocarbons may be produced by paralysis or steam cracking of hydrocarbons including hydrocarbons derived from coal, hydrocarbons derived from synthetic crude, naphtha’s, refinery gases, ethane, propane, butane, and the like. Unsaturated hydrocarbons may also be produced by the conversion of alcohols. Unsaturated hydrocarbons produced in these manners usually contain small proportions of highly unsaturated hydrocarbons such as acetylenes and diolefins that adversely affect production of subsequent chemicals and polymers. Thus, to form an unsaturated hydrocarbon product such as a polymer grade monoolefin, the amount of acetylenes and diolefins in the monoolefin stream is typically reduced For example, in polymer grade ethylene, acetyl content typically is less than about 2 ppm, alternatively, less than about 1 ppm One technique commonly used to reduce the amount of acetylenes and diolefins in an unsaturated hydrocarbon stream primarily comprising monoolefins involves selectively liydrogmating the acetylenes and diolefins to monoolefins. This process is selective in that hydrogenation of the monoolefin and the highly unsaturated hydrocarbons to saturated hydrocarbons is minimized For example, the hydrogenation of ethylene or acetylene to ethane is minimized The selective hydrogenation may be performed using catalysts comprising palladium (Pd) on an inorganic support. However, in some circumstances, such selective hydrogenation catalysts can produce green oil by oligomerizing the acetylenes and diolefins. As used herein, green oil refers to molecules having more than four carbon atoms per molecule. Green oil is one of a number of contributors to the fouling of the selective hydrogenation catalysts and the resulting catalyst deactivation. The deactivation of the selective hydrogenation catalyst results in the catalyst having a lower activity and selectivity to unsaturated hydrocarbons. Green oil production is particularly apparent in backend hydrogenation reactors. A selective hydrogenation catalyst in such backend reactors requires regular regenei-ation, and with each regeneration cycle, the selectivity and the life of the catalyst decreases. Therefore, a need exists for a selective hydrogenation catalyst that undergoes less deactivation in between regeneration cycles during the hydrogenation of acetylenes and diolefins. SUMMARY OF THE INVENTION In an enibodinient, disclosed is a method for producing a selective hydrogenation catalyst for hydrogenating a highly unsaturated hydrocarbon to an unsaturated hydrocarbon surprising contacting an inorganic catalyst support with a chlorine-containing conjoin to form a chloride catalyst support (step (a)) and adding palladium to the chloride catalyst support to form a supported-palladium composition which is a selective hycirogenation catalyst composition. The method may further comprise removing from the chloride catalyst support an amount of chlorine-containing compound, decor position products thereof or other unwanted elements after step (a) to produce a clean chloride catalyst support having from about 10 to about 1200 ppm by weight chlorine. The method may further comprise adding at least one selectivity enhancer to the supported-palladium coroposition to form an enhanced supported-palladium composition, wherein the selectivity enhancer corn rises a surround selected from the group consisting of Group IB metals, Group IB metal , phosphorus, sulfur, phosphorus confounds, sulfur compounds, alkaline metals, alkanet metal compounds, iodine, iodide compounds, and combinations thereof The enhanced supported-palladium corrposition may comprise from about 0.001 to about 10 weight percent selectivity enhancer based on a total weight of the catalyst. The chlorine-containing may coin rise a compound selected from the group consisting of hydrochloric acid, an alkanet metal chloride, an alkaline earthly chloride, and combinations thereof Alternatively, the chlorine-containing compound may comprise a cornpone selected from the group consisting of potassium chloride, sod aim chloride, Atrium chloride, and combinations thereof Alternatively, the chlorine-containing compound may conjures a compound selected from the group consisting of calcium chloride, barium chloride, and combinations thereof Alternatively, the chlorine-containing compound may be described by the formula N(HvRwR'xR"yR'"OCl; where R, R', R", and R'" is methyl, ethyl, propyl, or butyl or any combination thereof; and v, w, x, y, z can be 0 to 4 provided v+w+x+y+z = 4. Alternatively, the chlorine-containing may coir rise a coir pound selected from the grugru) consisting of ammonium chloride, methyl ammonium chloride, tetramethylammonium chloride, tetraethylammonium chloride, and combinations thereof Alternatively, the chlorine-containing compound may comprise a compound described by the formula CClxHy; wherein x + y = 4. Iteratively, the chlorine-containing may surprise carbon tetrachloride. Alternatively, the chlorine-containing compound may croppies a corn pound described by the formula C2ClxHy; wherein x + y = 6. Alternatively, the chlorine-containing corn pound may comprise dichloromethane. The selective hydrogenation catalyst may comprise from about 0.01 to about 1.0 weight percent palladium based on a total weight of the catalyst. In an erobodiment, disclosed is a selective hydrogenation catalyst for hydrogenating a highly unsaturated hydrocarbon to an unsaturated hydrocarbon formed by the method comprising contacting an inorganic catalyst support with a chlorine- containing compound to form a chloride catalyst support and adding palladium to the chloride catalyst support to form a siqjported-palladimn coiqiosition which is a selective hydrogenation catalyst composition. In an embodiment, disclosed is a method of selectively hydrogenating a highly unsaturated hydrocarbon to an unsaturated hydrocarbon contacting the highly unsaturated hydrocarbon with a selective hydrogenation catalyst composition produced by contacting an inorganic catalyst support with a chlorine-containing to form a chlorides catalyst support and adding palladium to the chloride catalyst support to form a supported-palladium composition. A fouling rate of the selective hydrogenation catalyst may be at least about 25 percent less than a fouling rate of the same catalyst when not supported on a chlorides catalyst support under hydrogenation conditions. In an embodiment, disclosed is a catalyst for selectively hydrogenating a highly unsaturated hydrocarbon to an unsaturated hydrocarbon coin rising a chloride inorganic catalyst support, palladium, and silver. The catalyst may comprise from about 10 to about 1200, alternatively from about 20 to about 800 ppm by weight of chlorine; from about 0.01 to about 1.0, alternatively from about 0.01 to about 0.8 weight percent palladium based on a total weight of the catalyst; and (c) from about 0.01 to about 10, alternatively from about 0.01 to about 5 weight pecan silver based on a total weight of the catalyst The catalyst may feather comities one or more selectivity enhancers selected from the group consisting of iodine, iodide compounds, phosphorus, phosphorus compounds, slur, sulfur conjoins, alkaline metals, alkaline metal surrounds, and combinations thereof The catalyst may coir rise from about 0.001 to about 10 weight percent selectivity enhancer based on a total weight of the catalyst. The chloride inorganic catalyst support may have a surface area of from about 2 to about 100 m^/g. DESCRIPTION OF THE DRAWINGS The invention, together with further advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings in which: Figure 1 depicts a process flow diagram of an embodiment in which an unsaturated hydrocarbon stream containing a highly unsaturated hydrocarbon is fed to a hydrogenation reactor for selective hydrogenation of the highly unsaturated hydrocarbon to amonoolefin. Figure 2 is a graph illustrating the relative fouling curves during the hydrogenation of acetylene for one control selective hydrogenation catalyst and two selective hydrogenation catalysts comprising palladium on an inorganic catalyst support modified by a chlorine-containing compound Figure 3 is a graph illustrating the relative catalyst selectivity to ethylene during the hydrogenation of acetylene for one control selective hydrogenation catalyst and two selective hydrogenation catalysts palladium on an inorganic catalyst support modified by a chlorine-containing DETAILED DESCRIPTION OF THE INVENTION In an embodiment, a method of making a catalyst for selectively hydrogenating highly unsaturated hydrocarbons to unsaturated hydrocarbons comprises contacting an inorganic catalyst support with a chlorme-contaiaing compound to create a clilorided catalyst support. In an embodiments, the chlorine-containing confound is a gas, a liquid, or combinations thereof Palladium is subsequently added to the chlorided catalyst support to create a supported-palladium coiqposition useful as a. selective hydrogenation catalyst. A suitable selectivity enhancer may be optionally added to the supported-palladium composition thereby creating an enhanced supported-palladium coin position that is effective as a selective hydrogenation catalyst. The details of such methods are provided below. As used herein, a highly unsaturated hydrocarbon is defined as a hydrocarbon containing at least one triple bond, conjugated carbon-carbon double bond, or cumulative carbon-carbon double bond As used herein, an unsaturated hydrocarbon is defined as a containing an isolated carbon-carbon double bond Examples of highly unsaturated hydrocarbons include without limitation acetylene, methyl acetylene and procaine. Examples of unsaturated hydrocarbons include ethylene and propylene. It is also understood that the term "catalyst" refers to the support together with the materials impregnated in or on the support. Unless specified to the contrary or apparent from the plain meaning of a phrase, the word "or" has the inclusive meaning. In some embodiments, the catalyst support may comprise an inorganic support such as one or more aluminums, silica’s, titanium, zirconia’s, aluminosilicates (such as clays and/or zeolite), spinals (such as zinc alumdnate, zinc titanate, and/or magnesium aluminate), or combinations thereof In some embodiments, a suitable catalyst support is an alpha (a)-lamina support. A catalyst support having a surface area of from about 2 to about 100 square meters per gram (mug) may be einployed. Alternatively the support may have a surface area of from about 2 to about 75 m /g, or from about 3 to about 50 mVg. The surface area of the support may be determined using any method known to one of ordinary skill in the art, alternatively using the well-known method of Brinier, Emmett, and Teller ("BET") by measuring the quantity of nitrogen adsorbed on the catalyst. Alternatively, it can also be measured by mercury intrusion. A suitable mercury intrusion method is described in ASTM UOP 578-02, entitled "Automated Pore Volume and Pore Size Distribution of Porous Substances by MERCURY Proximity," which is incorporated herein by reference in its entirety. Particles of the catalyst support generally have an average diameter of from about 1 to about 10 nM, alternatively from about 2 to about 6 mm, and can have any suitable shape. In an erobodiment, the shape of the catalyst support may be cylindrical In an alternative enibodiment, the catalyst support may be spherical. Initially, the inorganic catalyst support is contacted with a chlorine-containing to create a chlorided catalyst support The chlorine-containing compound can be a gas, a Quid, or combinations thereof An embodiment contacting the inorganic catalyst support with a liquid chlorine-containing to create a chlorided catalyst support Such a liquid may surprise at least one chlorine-containing In some embodiments the Quid chlorine-containing compounds to which the inorganic catalyst support may be to create the chlorided catalyst support include, but are not limited to, hydrochloric acid; alkaline metal chloride; alkaline earth chloride; chlorohydrocarbons; cornpones described by the formula N(HvRwRVR"yR'" Cl, where R, R', R", and R'" is methyl, ethyl, propyl, butyl, or any combination thereof and v, w, x, y, z can be 0 to 4 provided v+w+x+y+z = 4; or combinations thereof In some embodiments, the alkaline metal chloride may comprise potassium chloride, sodium chloride, lithium chloride, or combinations thereof In some embodiments, the alkaline earth chloride may coin rise calcium chloride, barium chloride, or combinations thereof In some embodiments, compounds described by the formula N(HvRwR'xR"y' "'z)' comprise ammonium chloride, methyl ammonium chloride, tetramethylammonium chloride, tetraethylammonium chloride, or originations thereof Chloral-hydrocarbons as used herein may comprise compounds containing 1-10 carbons wherein there is at least one substitution of hydrogen for chlorine. In some embodiments chloral-hydrocarbons surprise compounds described by the formula CClxHy (where x + y = 4); compounds described by the formula C2ClxHy (where x + y = 6); or combinations thereof In some embodiments confounds described by the formula CClxHy comprise carbon tetrachloride, dichloromethane, or carbonations thereof In some embodiments, conjoins described by the formula CClxHy comprise dichloromethane. In an enibodiment, the liquid chlorine-containing compound surprises potassium chloride in solution. The inorganic catalyst support can be contacted with the liquid chlorine-containing surround in any suitable Maier that will yield a selective hydrogenation catalyst meeting the parameters described herein. In an embodiment, the method used to contact an inorganic catalyst support with a liquid chlorine-containing coin pound may be incipient wetness rogation, which is well known in the art. During incipient wetness impregnation, the pores of the support become substantially filled with the hquid chlorine-containing conipound. Other contacting methods such as soaking may also be employed to contact the inorganic catalyst support with tiled liquid chlorine-containing coinpound to create a chlorided catalyst support. An alternative embodiment initially contacting tie inorganic catalyst with a gaseous chlorine-containing compound to create a chlorided catalyst support. In some embodiments, the chlorine-containing confounds that may be ercpbyed as gases include, but are not limited to, hydrogen chloride gas, chlorine gas, CClxHy (where x + y = 4), C2ClxHy (where x + y = 6), or continuations thereof In another embodiment, the gaseous chlorine-containing confounds are obtained by heating a volatile chore-hydrocarbon or mixture thereof A method used to contact an inorganic catalyst support with a gaseous chlorine-containing coupon may be cacti plashed by heating the inorganic catalyst support in the presence of a gaseous chlorine-containing compound and optionally in the presence of oxygen, water, nitrogen, hydrogen or mixtures thereof to create a chlorided catalyst support. In an embodiment, the inorganic catalyst support may be contacted with a gaseous chlorine-containing corn pound at tertiparatures of from about 300°C to about 850°C for from about 0.2 to about 20 hours. The amount of chorine-containing compound deposited on the inorganic support is controlled independently of the contact method, whether by liquid contacting, gas phase contacting, or combination thereof The contacting method may deposit an amount of chlorine-containing confound such that the chlorided catalyst support, ie., the catalyst support after exposure to a chlorine-containing compound, comprises from about 20 to about 0.001 weight percent clitorises based on a total weight of the chlorided catalyst support, alternatively from about 10 to about 0.001 weight precut chlorine, alternatively from about 2 to about 0.001 weight percent chlorine. After the inorganic catalyst support has been contacted with the chlorine-containing coir pound to create the chlorided catalyst support, the clilorided catalyst support may be removed from contact with the chlorine-containing conpound and processed to remove from the chlorided catalyst support unwanted elements such as an amount of chlorine-containing conpound, decomposition products thereof, or other unwanted elements to create a clean chlorided catalyst support and otherwise prepare the chlorided catalyst support for exposure to palladium. Removing an amount of chlorine-containing and/or any other unwanted elements may occur via a wash, via vaporization, or combinations thereof, depending, for exoxnple, on the type of chlorine-containing compound involved. The vaporization may be acconpHshed at a tercperature of from about 300°C to about 850°C for from about 0.2 to about 20 hours. After processing, the clean chlorided catalyst support may comprises from about 5 to about 2000 ppm by weight of chlorine; alternatively, may comprise from about 10 to about 1200 ppm by weight of chlorine; alternatively, from about 20 to about 800 ppm by weight of chlorine; alternatively, from about 30 to about 400 ppm by weight of chlorine with respect to the support. In an embodiment, a chlorided catalyst support produced by contact with a hquid chlorine-containing conpound may be exposed to an elevated temperature of from about 50 °C to about 850 °C for from about 0.5 to about 20 hours to dry and/or cline the chlorided catalyst support, thereby producing a cleaned chlorided catalyst support. In some embodiments, an optional washing step may follow the exposure to an elevated temperature. For sextuple, the may be washed with water at of from about 20 °C to about 100 °C for from about 1 minute to about 2 hours. In an embodiment, the washing utilizes boiling distilled or deionized water and occurs after drying and/or calcining. Following the washing step, the chlorided catalyst support may optionally undergo another exposure to an elevated temperature of from about 50 °C to about 900 °C for from about 0.5 to about 20 hours to remove any unwanted moisture. In another einbodiment, a chlorided catalyst support produced by contact with a gaseous chlorine-containing may be cleaned via vaporization or washing or a combination thereof to remove an amount of chlorine containing compound, decoirposition products thereof, or other unwanted elements. In an embodiment, after contacting the inorganic catalyst support with the gaseous chlorine-containing confound, flow of the gaseous chlorine containing compound is stopped, and the gaseous treated chlorided catalyst support may be continued to be heated and/or acclaimed by exposure to an elevated tenperature in the absence of the gaseous chlorme containing compound to produce a cleaned chlorided catalyst support. Exposure to an elevated may occur in the presence of oxygen, water, nitrogen and mixtures thereof for less than or equal to about 18 hours. This vaporization removal step may be optionally followed by exposing the chlorided catalyst support with a heated stream of gas free of the chlorine containing compound to further remove any unwanted elements. After processing, the cleaned chlorided catalyst support may comprise from about 5 to about 2000 ppm by weight of chlorine; alternatively, may coin rise from about 10 to about 1200 ppm by weight of chlorine; alternatively, from about 15 to about 800 ppm by weight of chlorine; alternatively, from about 15 to about 400 ppm by weight of chlorine with respect to the support. Next, palladium may be added to the clean chlorided catalyst support to create a supported-palladium composition. Addition of the palladium may be accomplished by contacting the support with a palladium-containing solution comprising palladium metal or a palladium containing compound such as palladium chloride or palladium nitrate using any suitable manner that will yield a selective hydi'ogenation catalyst meeting the parameters described herein. In an embodiment^ the palladium-containing solution is an aqueous solution. In an embodiment, the method used to contact a clean chlorided catalyst support with a palladium-containing solution may be incipient wetness impregnation, which is well known in the art. The palladium-containing solution may contain a sufficient amount of palladium to form a supported-palladium having from about 0.01 to about 1.0 weight percent palladium, alternatively from about 0.01 to about 0.8 Wight percent palladium, alternatively from about 0.01 to about 0.5 weight percent palladium, all weight percentages being by weight of the supported-palladium composition. In an embodiment, the palladium-containing solution is added to the clean chlorided catalyst support in a manner to cause at least about 95 weight percent of the supported-palladium composition particles to have the palladium concentrated near the periphery of the supported-palladium composition particles such that those particles have a so-called palladium skin. As used herein, the term "palladium skin" refers to a peripheral layer of the exported-palladium composition that contains at least about 95 weight percent of the palladium incorporated in the support The palladium slunk can be any thickness as long as such thickness can promote the hydrogenation process disclosed herein. Generally, the thickness of the palladium skin can be in the range of from about 1 micron to about 3000 microns, alternatively from about 5 microns to about 2500 microns, alternatively from about 5 microns to about 2000 microns. For further reference, the teachings of U.S. Pat Nos. 4,404,124 and 4,484,015 are instructive and are incorporated by reference herein. Suitable methods for determining the concentration of the palladium in the skin of the supported-palladium composition are known in the art. Determining the concentration of the palladium in the skin of the supported-palladium composition helps in detonating the thickness of the skin. One technique that may be employed to determine the palladium skin thickness is the electron microprobe method. Another technique involves breaking open a representative sample of the supported-palladium particles and treating the supported-palladium composition particles with a dilute alcoholic solution of N,N-dimethyl-para-nitrosoa2flline. The treating solution reacts with the palladium to give a red color that can be used to evaluate the distribution of the palladium Yet another technique for measuring the concentration of the palladium in the skin of the supported-palladium compositions involves breaking open a representative sanple of catalyst particles, followed by treating the particles with a reducing agent such as hydrogen to change the color of the skin and thereby evaluate the distribution of the Palladian The supported-palladium corn position formed by contacting the clean chlorided catalyst with the palladium-containing solution optionally may be dried at a temperature of from about 25 °C to about 150 C for a period of from about 0.5 hour to about 20 hours to produce a selective hydrogenation catalyst. The supported-palladium composition described above may optionally be further claimed at a tenperature of from about 200 °C to about 850 °C for a period of from about 0.2 to about 20 hours. In aa alternate embodiment, one or more selectivity enhancers may be added to the supported-palladium composition to produce an enhanced supported-palladium composition useful as a selective hydrogenation catalyst. In one embodiment, this addition can occur by soaking the supported-palladium composition in a liquid composing one or more suitable selectivity enhancers. In another embodiment, this addition can occur by incipient wetness rogation of the supported-palladium composition with liquid con:5)rising one or more suitable selectivity enhancers. This additional step may be optionally followed by again drying and/or calcining the enhanced sis -palladium corn position as described above to produce an enhanced supported-palladiiun composition useful as a selective hydrogenation catalyst. In an embodiment, suitable selectivity enhancers include, but are not limited to, Group IB metals, Group IB metal compounds, phosphorus, sulfur, phosphorus coir pounds, sulfur compounds, alkaline metals, alkaline metal compounds, iodine, iodide coir pounds, or combinations thereof In an embodiment, the selectivity enhancer con:5)rises silver (Ag), silver corn pounds, iodine, iodine compounds, or combinations thereof For example, silver in the form of a silver compound such as silver nitrate may be added to the supported-palladium composition. In an erobodiment the resulting enhanced supported-palladium composition may comprise from about 0.001 weight percent to about 10 weight percent of the selectivity enhancer, alternatively from about 0.01 weight percent to about 5 weight percent selectivity enhancer, alternatively from about 0.01 weight percent to about 2 weight percent selectivity enhancer, all weight percentages being based on a total weight of the enhanced supported palladium In an alternative embodiment the resulting enhanced supported-palladium may comprise from about 0.01 weight percent to about 10 weight percent silver, alternatively from about 0.01 Wight percent to about 5 weight percent silver, alternatively from about 0.01 weight percent to about 2 weight percent silver. In a further embodiment, lie resulting enhanced supported-palladium composition may coin rise from about 0.001 weight percent to about 10 weight percent iodine, alternatively from about 0.01 weight percent to about 5 weight percent iodine, alternatively from about 0.01 weight percent to about 2 weight percent iodine. In an embodiment, iodine may optionally be added to the enhanced supported-palladium corn position in addition to silver using a number of techniques, e.g., incipient wetness irrigation or soaking, and the support may again be dried and/or claimed to produce an enhanced supported-palladium composition useful as a selective hydrogotiation catalyst. Iodine may be added simultaneously with the silver, or sequentially before or after the silver. The concentration of iodine in the resulting selective hydrogenation catalyst may range from about 1 ppm to about 1,000 ppm by weighty alternatively from about 1 ppm to about 800 ppm by weight, alternatively from about 1 ppm to about 500 ppm by weight all ppm by weight being based on a total weight of the enhanced supported palladium composition. In some embodiments, the suitable iodine-containing materials include, but are not hinted to, elemental iodine, ammonium iodide, potassium iodide, tetraalkylammonium iodide (e.g., tetramethylammonium iodide and tetraethylammonium iodide), potassium iodate, ammonium iodide, or combinations thereof The resulting selective hydrogenation catalyst can be dried and/or calcite prior to using the selective hydrogenation catalyst in the hydrogenation process. In some embodiments, this draying step can be carried out at a in the range of from about 25 to about 150"C for a period of from about 0.5 hour to about 20 hours. In some embodiments, this calciniag step can be carried out at tenperatures up to about 850°C, e.g., in the range of from about 150'C to about 700°C, for a period of from about 0.2 to about 20 hours. In some embodiments, the one or more selectivity enhancers can be distributed throughout the enhanced supported-palladium using methods known to those skilled ia the art. In an embodiment, the supported-palladium composition particles can be placed in an aqueous silver nitrate solution of a quantity greater than that necessary to fill the pore volume of the particles. The resulting enhanced supported-palladium may be dried and/or claimed to decompose the silver-containing before using the enhanced supported-palladium composition as a catalyst in the selective hydrogenation process. In some embodiments, this drying may be performed at a terrperature in the range of from about 25°C to about 150°C for a period of from about 0.5 to about 20 hours. In some embodiments^ this calcining step may be performed at temperatures up to about 850^0, e.g., in the range of from about 150°C to about 750°C, for a period of from about 0.2 to about 20 hours. Optionally, the drying or calcining may be followed by a reduction step to reduce the metals (e.g., catalytic metals) in the enhanced supported-palladium conapositiou This reduction step may be accomplished in a variety of ways, all well known in the art. One embodiment comprises reducing the enhanced supported-palladium using hydrogen gas or a hydrogen gas containing feed, e.g.,, the feed stream of the selective hydrogenation process, to reduce the catalytic metals, thereby providing for optimum operation of the selective hydrogenation process. Such a gaseous hydrogen reduction may be carried out at a temperature vi the range of from, for about 25°C to about 450°C. In an embodiment, a selective hydrogenation catalyst compositions formed in accordance with the method described above comprises an a-lamina support treated with a chlorine-containing conpound, palladium, and optionally at least one selectivity enhancer, e.g., silver and/or iodine. Further, such a selective hydrogenation catalyst may can’s a support having a surface area of from about 2 to about 100 square meters per gram (mVg); alternatively from about 2 to about 75 mVg, or from about 3 to about 50 m^/g. In some embodiments, methods of using the previously described selective hydrogenation catalysts, for example in a selective hydrogenation process, currieries contacting an unsaturated hydrocarbon stream primarily containing an unsaturated hydrocarbon, e.g., ethylene, but also containing a highly unsaturated hydrocarbon, e.g., acetylene, with such catalyst compositions. The contacting may be executed in the presence of hydrogen at conditions effective to selectively hydrogenate the highly unsaturated hydrocarbon to an unsaturated hydrocarbon. In an embodiment, the selective hydrogenation catalysts of this disclosure are used in the hydrogenation of highly unsaturated hydrocarbons such as for example and without limitation acetylene, methyl acetylene, procaine or combinations thereof Figure 1 illustrates an embodiment of a hydrogenation process that utilizes a selective hydrogenation catalyst made in the manner described above. The hydrogenation process includes feeding an unsaturated hydrocarbon stream 10 and a hydrogen (H2) stream 20 to a hydrogenation reactor 30 within which the selective hydrogenation catalyst is disposed. The unsaturated hydrocarbon stream 10 primarily comprises one or more unsaturated hydrocarbons, but it also contains one or more highly unsaturated hydrocarbons such as for example and without imitation acetylene, methyl acetylene and procaine. Alternatively, unsaturated hydrocarbon stream 10 and hydrogen stream 20 may be combined in a single stream (not shown) that is fed to hydrogenation reactor 30. Accordingly, unsaturated hydrocarbon stream 10 may con:5)rise hydrocarbons, including one or more unsaturated hydrocarbons such as ethylene and one or more highly unsaturated hydrocarbons such as acetylene, methyl acetylene and procaine. In an embodiment, reactor 30 is a selective hydrogenation reactor that may belong to an acetylene removal unit of an unsaturated hydrocarbon production plant in a backend configuration. As used herein, 'lacked" refers to the location of the acetylene removal unit in an unsaturated hydrocarbon production unit that receives tithe lower boiling fixation from a deethanizer fractionation tower that receives the higher boiling fraction from a demethanizer fractionation tower that receives a feed from an unsaturated hydrocarbon production process. In an embodiment, reactor 30 is a selective hydrogenation reactor that may belong to an acetylene removal unit of an unsaturated hydrocarbon production plant in a frontend deethanizer configuration. As used herein, "front end deethanizer" refers to the location of the acetylene removal unit in an unsaturated hydrocarbon production unit that receives the lower booing fraction from a deethanizer fractionation tower that receives a feed from an unsaturated hydrocarbon production process. In an embodiment, reactor 30 is a selective hydrogenation reactor that may belong to an acetylene removal unit of an unsaturated hydrocarbon production plant in a frontend depropanizer configuration. As used herein, "frontend depropanizer" refers to the location of the acetylene removal unit in an unsaturated hydrocarbon production unit that receives the lower boiling fraction from a depropanizer fractionation tower that receives a feed from an unsaturated hydrocarbon production process. In an embodiment, reactor 30 is a selective hydrogenation reactor that may belong to an acetylene removal unit of an unsaturated hydrocarbon production plant in a raw gas configuration. As used herein, 'raw gas" refers to the location of the acetylene removal unit in an unsaturated hydrocarbon production unit that receives a feed from an unsaturated hydrocarbon production process without any starveling hydrocarbon fractionation. It is understood that hydrogenation reactor 30, and likewise the selective hydrogenation catalysts disclosed herein, is not limited to use in backend acetylene removal units, frontend deethanizer units, frontend depropanizer, or raw gas units and may be used in any process wherein a higlily unsaturated hydrocarbons contained within an unsaturated hydrocarbon stream is selectively hydrogenated to a unsaturated hydrocarbon. In those embodiments wherein the acetylene removal unit is in a backend configuration, the highly unsaturated hydrocarbon being fed to the hydrogenation reactor 30 conqjrises acetylene. The mole ratio of the hydrogen to the acetylene being fed to hydrogenation reactor 30 may be in the range of from about 0.1 to about 10, alternatively from about 0.2 to about 5, alternatively from about 0.5 to about 3. In those embodiments wherein the acetylene removal unit is in a front end deethanizer, front-end depropanizer or raw gas configuration, the highly unsaturated hydrocarbon being fed to the hydrogenation reactor 30 con:5)rises acetylene. In such an embodiment, the mole ratio of the hydrogen to the acetylene being fed to the hydrogenation reactor 30 may be in the range of from about 10 to about 3000, alternatively from about 10 to about 2000, alternatively from about 10 to about 1500. • In those embodiments wherein the acetylene removal unit is in a front-end depropamzer or raw gas configuration, the highly unsaturated hydrocarbon being fed to the hydrogenation reactor 30 methyl acetylene. In such an embodiment, the mole ratio of the hydrogen to the methyl acetylene being fed to the hydrogenation reactor 30 may be in the range of from about 3 to about 3000, alternatively from about 5 to about 2000, alternatively from about 10 to about 1500. In those embodiments wherein the acetylene removal unit is in a front-end depropanizer or raw gas configuration, the highly unsaturated hydrocarbon being fed to the hydrogenation reactor 30 comprises procaine. In such an embodiment, the mole ratio of the hydrogen to tile procaine being fed to the hydrogenation reactor 30 may be in the range of from about 3 to about 3000, alternatively from about 5 to about 2000, alternatively from about 10 to about 1500. In another embodiment, reactor 30 may represent a plurality of reactors. The plurality of reactors may optionally be separated by a means to remove heat produced by the reaction. The plurality of reactors may optionally be by a means to control inlet and effluent flows from reactors or heat removal means allowing for individual or alternatively groups of reactors within the plurality of reactors to be regenerated The selective hydrogenation catalyst may be arranged in any suitable configuration within hydrogenation reactor 30, such as a fixed catalyst bed Carbon monoxide may also be fed to reactor 30 via a separate stream (not shown), or it nay be combined with hydrogen stream 20. In an enibodiment, the amount of carbon monoxide being fed to reactor 30 during the hydrogenation process is less than about 0.15 mol% based on the total moles of fluid being fed to reactor 30. Hydrogenation reactor 30 may be ulcerated at conditions effective to selectively hydrogenate highly unsaturated hydrocarbons to one or more unsaturated hydrocarbons upon contacting the selective hydrogenation catalyst in the presence of the hydrogen. The conditions are desirably effective to maximize hydrogenation of highly unsaturated hydrocarbons to unsaturated hydrocarbons and to minimize hydrogenation of highly unsaturated hydrocarbons to saturated hydrocarbons. In some embodiments, acetylene may be selectively hydrogenated to ethylene. Alternatively methyl acetylene may be selectively hydrogenated to ethylene; alternatively procaine may be selectively hydrogenated to propylene. In some embodiments, the temperature within the hydrogenation zone may be in the range of from about 5°C to about 300'C, alternatively from about to about 250°C, or from about 15°C to about 200°C. In some embodiments, the pressure within the hydrogenation zone may be in the range of from about 15 (204 kPa) to about 2,000 (13,890 kPa) pounds per square inch gauge (psig), alternatively from about 50 psig (446 kPa) to about 1,500 psig (10,443 kPa), or from about 100 psig (790 IcPa) to about 1,000 psig (6,996 kPa). Referring back to Figure 1, an effluent stream 40 comprising unsaturated hydrocarbons, including the one or more mongolisms produced in hydrogenation reactor 30, and any unconverted reactants exit hydrogenation reactor 30. In an enibodiment, effluent stream 40 primarily comprises ethylene and contains less than about 5 ppm, desirably less than about 1 puma highly unsaturated hydrocarbons. The selective hydrogenation catalyst contained in hydrogenation reactor 30 may be regenerated as needed. In some embodiments, regeneration of the selective hydrogenation catalyst may be by optionally stream stripping the selective hydrogenation catalyst then calcining the catalyst in the presence of a gas oxygen at a not in excess of about 500'C to bum off any organic matter, polymer, or char. EXAMPLES The invention having been generally described, the following example exemplifies embodiments of the invention and demonstrates the practice and advantages thereof It is understood that these externals are given by way of illustration and are not intended to limit the specification or the following claims in any manner. All numerical values are approximate. When numerical ranges are given, it should be understood that embodiments outside tile stated ranges may suit fall within the scope of the invention. Specific details described in each example should not be construed as necessary features of ties invention. In the following examples, the amount of green oil produced by each selective hydrogenation catalyst was calculated as follows: weight % green oil = final catalyst weight - initial catalyst weight)/initial catalyst weighty days on stream)* 100 Further, the selectivity (seL) to ethylene was also calculated using the following set of equations, where "C4" represents butane, butanes and butadiene and where 'leaves" refer to hydrocarbons having more carbon atoms than C4: selectivity to ethane = (weight of ethane made/weight of acetylene consumed)* 100 selectivity to C4's = (weight of C4's made/weight of acetylene consumed)100 selectivity to heavies = (weight of heavies made/weight of acetylene consumed)100 selectivity to ethylene = 100 -• seL to ethane - seL to C4's - seL to heavies The fouling rate was determined by plotting reaction temperature, while maintaining the acetylene conversion at 90%, as a function of time for each sample and then taking the slope of that line. A selectivity comparison was also made by plotting the selectivity to ethylene at 90% acetylene conversion as a fiction of time for each sanple and then integrating the curve from 0 to 200 hours. Table 1, below, shows these fouling rate and selectivity area values flier 200 hours on stream. The area values represent the results of integrating the selectivity curves from 0 to 200 hours. In the following examples, the amount of chlorine on the chlorinated inorganic support, the selective hydrogenation catalyst or any intennediate product was determined by x-ray spectroscopic methods. In this method samples were pulverized in a ball mill and pressed into a 31 mm disk. X-Ray Florescence data (XRF) was collected The concentrating of chorine was determined using a standard less analysis software package. All concentrations are semi quantitative. EXAMPLE 1 The following example illustrates the preparation of various palladium-containing selective hydrogenation catalyst san:5)les, and the use of the samples in a selective hydrogenation process. Catalyst A (control) was prepared on a-Al203 pellets supplied by Sid Chemie of Louisville, Kentucky, USA in the form of 4mm x 4mm tablets as described in U. S. Pat No. 4,484,015. The a-Altos pellets had a surface area of about 5 to about 7 mVg (determined by the BET method N2). Catalyst A contained 0.02 weight percent palladium and 0.12 weight percent silver and 99 weight percent AI2O3. Catalyst B was prepared as foods: an aqueous solution of about 1.13g NH4CI in about 16g distilled water was added to about 50g of a-Haps pellets (4mm x 4mm, surface area of about 5 to about 7 mVg, provided by Slid Chemie of Louisville, Kentucky, USA) followed by drying at about 125°C for about 1 ho\ir. The support was then claimed at about 538°C for about tire hours in air. Next about 0.02 weight percent palladium and about 0.12 weight percent silver were added as described in U.S. Pat No. 4,484,015. Catalyst C was prepared as follows; an aqueous solution of about 7.49g Kill in about 92 g distilled water was added to about 325g of a- AI2O3 pellets (4mm x 4mm, surface area of about 5 to about 7 mVg, provided by Sid Chemie of Louisville, Kentucky, USA) followed by drying at about 125°C for about 1 hour. The support was then calcite at about 850°C for about 2 hours in air. The support was lien washed repeatedly with boiling distilled water until the wash solution gave a negative chlorine test with an about IM Agony sedition. The subsequent was dried at about 125°C for about 1 hour and claimed at about 538^C for about 3 hours. Next about 0.02 weight percent palladium (Pd) and about 0.12 weight percent silver (Ag) were added as described in U.S. Pat No. 4,484,015. Reactor runs with each of the above catalysts, A through C, were made under laboratory test conditions. Laboratory test conditions are performed in the following manner: about 20 mL of catalyst was mixed with about 40 mL of 14 grit landmine and placed in a stainless steel jacketed reactor tube having an inner diameter of about 0.62 inch (15.7 nun) and a length of about 18 inches (457 mm). The reactor had a 3/16" thermo well running the length of the catalyst bed in the center of the reactor. The catalyst bed resided trio the middle of the reactor and both ends of the reactor were packed with about 40 mL of launder. The reaction teirperature was controlled by circulating ethylene glycol through the jacket of the reactor tube. The catalyst was then activated with hydrogen at a flow rate of about 200 mL/min at atmospheric pressurize at 170T (77°C) for two hours. Next, the catalyst was contacted with a feed gas comprising approximately 13 weight percent multilane, 85.8 weight percent ethylene, 1.2 weight percent acetylene, at a flow rate of about 913 mL/min at about 200 psig (1480 kPa). Hydrogen was added to give an about 1.3 molar ratio of hydrogen to acetylene. The reaction tenperature was adjusted to yield an acetylene conversion of about 90%. Conversion is referred to as the disappearance of acetylene. Gas analyses woe-e performed by gas chromatography using an AI2O3 plot column. Selectivity’s were calculated on a weight basis. Table I, below, contains pertinent data regarding the predominance of the catalysts, A through C, described above. As indicated by the data in Table 1, contacting an inorganic catalyst support with a chlorine-containing conpound increases the selectivity to ethylene among selective hydrogenation catalysts comprisal palladium Catalysts B and C, each modified by contacting with either NH4CI or KCl, both demonstrate significantly higher selectivity’s to ethylene ordered to control catalyst A In addition, the foul rate for catalysts B and C is lower than that of the control catalyst. In addition, green oil production is reduced. EXAMPLE 2 Figure 2 illustrates relative foul curves in degrees Fahrenheit per hour (°F/hour) for one control selective hydrogenation catalyst A, and two catalysts prepared in accordance with the methods described herein for use in an otherwise typical hydrogenation process (selective hydrogenation catalysts B and C). Line 200 tracks reactor temperature over time for a reactor run made with the control Catalyst A. Catalyst A is a selective hydrogenation catalyst corn rising palladium/silver supported on an AI2O3 support. Line 210 tracks reactor temperature over time for a reactor run made using Catalyst B, which is a selective hydrogenation catalyst corcprisiug palladium/silver supported on a chlorided catalyst support produced using ammonium chloride as the chlorine-containing conpound Line 220 tracks reactor temperature over time for a reactor run made using Catalyst C, which is a selective hydrogenation catalyst comprising palladium/silver supported on a chlorided catalyst support produced using potassium chloride as the chlorine-containing conpound The fouling rate related to line 200 is about 0.17 degrees Fahrenheit per hour. The fouling rate indicated by line 210 is about 0.07 degrees Fahrenheit per hour, and the fouling rate indicated by line 220 is about 0.14 degrees Fahrenheit per hour. Thus, the fouling rate demonstrated by the selective hydrogenation catalysts comprising inorganic catalyst supports modified by chlorine-containing compounds (hue 210 and 220) are reduced relative to the control catalyst. The lower fouling rates related by line 210 and 220 are also associated with a reduction in green oil generation when compared to the control catalyst (200). The fouling rate for a selective hydrogenation catalyst as described herein may be, for example, at least about 25 percent less, at least about 50 percent less, or at least about 80 percent less than a fouling rate of the same catalyst when not contacted witli a* chlorine-containing compound and run under control conditions. EXAMPLE 3 For the selective hydrogenation catalysts and reactor runs described in Example 2, Fig. 3 illustrates relative data for selectivity to ethylene. Line 300 tracks selectivity to ethylene over time of the control catalyst A. Lines 310 and 320 track the selectivity to ethylene over time of the catalysts comprising palladium and a support modified by a chlorine-containing coinpound (Catalysts B and C). The selectivity for ethylene indicated by line 310 and 320 are greater relative to the selectivity indicated by the control catalyst (line 300). Furthermore, the selectivity represented by line 310 and 320 is more stable over time than line 300, The percent selectivity improvement may be based on the integrated area under the selectivity versus time curve in Fig. 3 as shown in Table 1. As a result of improvements in fouling rate, green oil production, and selectivity to unsaturated hydrocarbons, the life of the selective hydrogenation catalyst is extended such that the catalyst requires regeneration less often, resulting in lower operating costs of the hydrogenation process. EXAMPLE 4 The following example illustrates the application of the catalyst in a front-end depropanizer reactor process. Hydrogenation runs were made with 20 cc of the previously described catalysts. The catalysts were placed in a stainless steel reactor tube having a 0.62 inch inner diameter and a length of about 18 inches. The catalyst resided in the middle of the reactor, and both ends of the reactor were packed with 10 mL of launder The catalyst was reduced at about 100°F for about 1 hour under hydrogen gas flowing at 200 nil/min and at 200 pounds per square inch gauge (psig). A feed stream typical of a feed from the top of a de-procaine fractionation tower in an ethylene plant was prepared, except that the ethane and propane were replaced with methane to aid in the selectivity calculations. The feed stream contained approximately (all by weight unless otherwise noted): hydrogen 2.5%; methane 40%; ethylene 41%; propylene 15%; acetylene 3500 ppm procaine 1800 ppm; methyl acetylene 1600 ppn and carbon monoxide 23 0 ppm (by volume). The feed stream was introduced into the reactor at a flow rate of 900 mL per minute at 200 psig translating to a gas hourly space velocity of about 2700 hour-1. The reactor tenperature was increased until the hydrogenation reaction ran away, ie., the uncontrollable hydrogenation of ethylene was allowed to occur. The reactor was then allowed to cool to room temperature before data collection was started Feed at 900mL/min and 200 psig was passed over the catalyst while holding the temperature constant before the exit stream by gas chromatography. The catalyst was determined by inserting a thermocouple into the thermo well and varying its position until the highest was observed The fumace was then raised a few degrees, and the testing cycle was repeated until 3 weight % of ethane was produced A of catalyst B was tested using the above protocol as wet as a control sample (catalyst A), the results are presented in Table 2. The results indicate that catalyst B has a higher MAPD conversion and a higher ethylene selectivity than the control catalyst at the same reaction tenperatoe. Furthermore catalyst B has a similar to higher acetylene conversion at the same temperatures. While embodiments of the invention have been shown and described, modifications thief can be made by one skilled in the art without departing from the spirit and teachings of the invention. The embodiments described herein are exemplary only, and are not intended to be smiting. Many variations and modifications of the invention disclosed herein are possible and are within the scope of the invention. Where numerical ranges or limitations are expressly stated, such actress ranges or limitations should be understood to include iterative ranges or Imitations of like magnitude falling within the expressly stated ranges or limitations (e.g., from about 1 to about 10 includes, 2, 3, 4, etc.* greater than 0.10 includes 0.11, 0.12, 0.13, etc.). Use of the term "optionally" with respect to any element of a claim is intended to mean that the subject element is required, or alternatively, is not required Both alternatives are inside to be within the scope of the claim. Use of broader terms such as corpuses, includes, having, etc. should be understood to provide support for narrower terms such as consisting o consisting essentially of, substantially of, etc. Accordingly, the scope of protection is not Muted by the description set out above but is only limited by the claims which follow, that scope including all equivalents of the subject matter of the claims. Each and every claim is incorporated into the specification as an embodiment of tie present invention. Thus, the claims are a feather description and are an addition to the embodiments of the present invention. The disclosures of all patents, patent applications, and publications cited herein are hereby incorporated by reference, to the extent that they provide , procedural or other details supplementary to those set forth herein. CLAIMS: 1. A method of producing a selective hydrogenation catalyst corn rising: (a) contacting an inorganic catalyst support with a chlorine-containing compound to form a chlorided catalyst support; and (b) adding palladium to the chlorided catalyst support to form a supported-palladium composition, 2. The method of claim 1, wherein the chlorine-containing composite comprises hydrochloric acid, an alkaline metal chloride, an alkaline earth chloride, chlorohydrocarbons, or combinations thereof 3. The method of claim 1, wherein the chlorine-containing conjoined con:5)rises a confound described by the formula N(HvRwR'xR"yR'" Cal; where R, R', R", and R'" is methyl, ethyl, propyl, butyl, or any combination thereof; and each of v, w, x, y, 2 can be 0 to 4 provided that v+w+x+y+z == 4. 4. The method of claim 1, wherein the chlorine-containing compound conprises a confound described by the formula CClxHy, wherein x + y = 4. 5. The method of claim 1, wherein the chlorine-containing a compound described by the formula C2ClxHy, wherein x + y = 6. 6. The method of claim 1, wherein the chlorine containing compound conprises potassium chloride, sodium chloride, thrum chloride, calcium chloride, barium chloride, ammonium chloride, methyl ammonium chloride, tetramethylammonium chloride, tetraethyl ammonium chloride, carbon tetrachloride, tricolors ethane, or combinations thereof 7. The method of claim 1, further comprising cleaning the chlorided catalyst support to produce a clean chlorided catalyst support having from about 5 to about 2000 ppm by weight chlorine. 8. The method of claim 1, wherein the selective hydrogenation catalyst con:55rises from about 0,01 to about 1.0 weight percent palladiums based on a total weight of the catalyst. 9. The method of claim 1, fritter comprising drying the supported-palladium , calcining the supported-palladium composition, or both. 10. The method of claim 1, further comprising adding at least one selectivity enhancer to the supported-palladium composition to form an enhanced supported-palladium composition, wherein the selectivity enhancer comprises a compound selected from the group consisting of Group IB metals, Group IB metal compounds, phosphorus, sulfur, phosphorus-containing compounds, sulfur-containing confounds, alkaline metals, alkaline metal-containing compounds, silver, silver-containing coconuts, iodine, iodide-containing compounds, and combinations thereof 11. The method of claim 10, wherein the enhanced supported-palladium from about 0.001 to about 10 weight percent selectivity enhancer based on a total weight of the catalyst. 12. The method of claim 10, further comprising drying the enhanced supported-palladium composition, calcining the enhanced supported-palladium composition, or both. 13. The method of claim 1, further comprising reducing the supported-palladium composition. 14. A method of selectively hydrogenating a highly unsaturated hydrocarbon to aii unsaturated hydrocarbon comprising: contacting under hydrogenation conditions the highly unsaturated hydrocarbon with a selective hydrogenation catalyst composition produced by the method of claim 1. 15. the method of claim 14, wherein a fouling rate of the selective hydrogenation catalyst is at least about 25 percent less than a fouling rate of an otherwise same catalyst having anon-chlorided catalyst support under like hydrogenation conditions. 16. The method of claim 14, wherein the highly unsaturated hydrocarbon surprises acetylene, methyl acetylene, procaine, or combinations thereof 17. A selective hydrogenation catalyst (a) a chlorided inorganic catalyst support containing from about 5 to about 2000 ppm by weight of chlorine; (b) about 0.01 to about 1.0 weight percent palladium based on a total weight of the catalyst; and (c) about 0.01 to about 10 weight percent silver based on a total weight of the catalyst. 18. The catalyst of claim 17, wherein the chlorided inorganic catalyst support compass from about 10 to about 1200 ppm by weight of chlorine based on a total weight of the catalyst, wherein the catalyst conprises from about 0.01 to about 0.8 weight percent palladium based on a total weight of the catalyst, and wherein the catalyst from about 0.01 to about 5 weight percent silver based on a total weight of the catalyst. 19. The catalyst of claim 17, further comprising one or more selectivity enhancers selected from the group consisting of iodine, iodide-containing compounds, phosphorus, phosphorus-containing compounds, sulfur, sulfite-containing compounds, alkaline metals, alkaline metal-containing coir pounds, and combinations thereof 20. The catalyst of claim 19, wherein the selective hydrogenation catalyst comprises from about 0.001 to about 10 weight percent selectivity enhancer based on a total weight of the catalyst.

Full Text

A SELECTIVE HYDROGENATION CATALYST AND METHODS OF MAKING AND USING SAME
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims priority under 35 U.S.C. § 119(e) to U.S. provisional patent application number 60/702,745 entitled "A Selective Hydrogenation Catalyst and Methods of Making and Using Same" and filed on July 27, 2005. Furthermore, the subject matter of this application is related to the subject matter of U.S. provisional patent application number 60/388,307 entitled "Hydrogenation Palladium-Silver Catalyst and Methods" and filed on June 14, 2002, U.S. patent application number 10/457,635 entitled "Hydrogenation Palladium-Silver Catalyst and Methods" and filed on June 9, 20Q3, and U.S. patent application number 10/741,800 entitled '"Methods of Making and Using a Selective Hydrogenation Catalyst" and filed on December 19, 2003. Each of the foregoing applications is hereby incorporated by reference herein in its entirety.
FIELD OF THE INVENTION
The present invention relates to the production of unsaturated hydrocarbons, and more particularly to a selective hydrogenation catalyst and methods of making and using the same to selectively hydrogenate highly unsaturated hydrocarbons.
BACKGROUND OF THE INVENTION
Unsaturated hydrocarbons such as ethylene and propylene are often loved as feedstock’s in preparing value added chemicals and polymers. Unsaturated hydrocarbons may be produced by paralysis or steam cracking of hydrocarbons including hydrocarbons derived from coal, hydrocarbons derived from synthetic crude, naphtha’s, refinery gases, ethane, propane, butane, and the like. Unsaturated

hydrocarbons may also be produced by the conversion of alcohols. Unsaturated hydrocarbons produced in these manners usually contain small proportions of highly unsaturated hydrocarbons such as acetylenes and diolefins that adversely affect production of subsequent chemicals and polymers. Thus, to form an unsaturated hydrocarbon product such as a polymer grade monoolefin, the amount of acetylenes and diolefins in the monoolefin stream is typically reduced For example, in polymer grade ethylene, acetyl content typically is less than about 2 ppm, alternatively, less than about 1 ppm
One technique commonly used to reduce the amount of acetylenes and diolefins in an unsaturated hydrocarbon stream primarily comprising monoolefins involves selectively liydrogmating the acetylenes and diolefins to monoolefins. This process is selective in that hydrogenation of the monoolefin and the highly unsaturated hydrocarbons to saturated hydrocarbons is minimized For example, the hydrogenation of ethylene or acetylene to ethane is minimized
The selective hydrogenation may be performed using catalysts comprising palladium (Pd) on an inorganic support. However, in some circumstances, such selective hydrogenation catalysts can produce green oil by oligomerizing the acetylenes and diolefins. As used herein, green oil refers to molecules having more than four carbon atoms per molecule. Green oil is one of a number of contributors to the fouling of the selective hydrogenation catalysts and the resulting catalyst deactivation. The deactivation of the selective hydrogenation catalyst results in the catalyst having a lower activity and selectivity to unsaturated hydrocarbons. Green oil production is particularly apparent in backend hydrogenation reactors. A selective hydrogenation

catalyst in such backend reactors requires regular regenei-ation, and with each regeneration cycle, the selectivity and the life of the catalyst decreases. Therefore, a need exists for a selective hydrogenation catalyst that undergoes less deactivation in between regeneration cycles during the hydrogenation of acetylenes and diolefins.
SUMMARY OF THE INVENTION
In an enibodinient, disclosed is a method for producing a selective hydrogenation catalyst for hydrogenating a highly unsaturated hydrocarbon to an unsaturated hydrocarbon surprising contacting an inorganic catalyst support with a chlorine-containing conjoin to form a chloride catalyst support (step (a)) and adding palladium to the chloride catalyst support to form a supported-palladium composition which is a selective hycirogenation catalyst composition. The method may further comprise removing from the chloride catalyst support an amount of chlorine-containing compound, decor position products thereof or other unwanted elements after step (a) to produce a clean chloride catalyst support having from about 10 to about 1200 ppm by weight chlorine.
The method may further comprise adding at least one selectivity enhancer to the supported-palladium coroposition to form an enhanced supported-palladium composition, wherein the selectivity enhancer corn rises a surround selected from the group consisting of Group IB metals, Group IB metal , phosphorus, sulfur, phosphorus confounds, sulfur compounds, alkaline metals, alkanet metal compounds, iodine, iodide compounds, and combinations thereof The enhanced supported-palladium corrposition may comprise from about 0.001 to about 10 weight percent selectivity enhancer based on a total weight of the catalyst.

The chlorine-containing may coin rise a compound selected from the group consisting of hydrochloric acid, an alkanet metal chloride, an alkaline earthly chloride, and combinations thereof Alternatively, the chlorine-containing compound may comprise a cornpone selected from the group consisting of potassium chloride, sod aim chloride, Atrium chloride, and combinations thereof Alternatively, the chlorine-containing compound may conjures a compound selected from the group consisting of calcium chloride, barium chloride, and combinations thereof Alternatively, the chlorine-containing compound may be described by the formula N(HvRwR'xR"yR'"OCl; where R, R', R", and R'" is methyl, ethyl, propyl, or butyl or any combination thereof; and v, w, x, y, z can be 0 to 4 provided v+w+x+y+z = 4. Alternatively, the chlorine-containing may coir rise a coir pound selected from the grugru) consisting of ammonium chloride, methyl ammonium chloride, tetramethylammonium chloride, tetraethylammonium chloride, and combinations thereof Alternatively, the chlorine-containing compound may comprise a compound described by the formula CClxHy; wherein x + y = 4. Iteratively, the chlorine-containing may surprise carbon tetrachloride. Alternatively, the chlorine-containing compound may croppies a corn pound described by the formula C2ClxHy; wherein x + y = 6. Alternatively, the chlorine-containing corn pound may comprise dichloromethane. The selective hydrogenation catalyst may comprise from about 0.01 to about 1.0 weight percent palladium based on a total weight of the catalyst.
In an erobodiment, disclosed is a selective hydrogenation catalyst for hydrogenating a highly unsaturated hydrocarbon to an unsaturated hydrocarbon formed by the method comprising contacting an inorganic catalyst support with a chlorine-

containing compound to form a chloride catalyst support and adding palladium to the chloride catalyst support to form a siqjported-palladimn coiqiosition which is a selective hydrogenation catalyst composition.
In an embodiment, disclosed is a method of selectively hydrogenating a highly unsaturated hydrocarbon to an unsaturated hydrocarbon contacting the highly unsaturated hydrocarbon with a selective hydrogenation catalyst composition produced by contacting an inorganic catalyst support with a chlorine-containing to form a chlorides catalyst support and adding palladium to the chloride catalyst support to form a supported-palladium composition. A fouling rate of the selective hydrogenation catalyst may be at least about 25 percent less than a fouling rate of the same catalyst when not supported on a chlorides catalyst support under hydrogenation conditions.
In an embodiment, disclosed is a catalyst for selectively hydrogenating a highly unsaturated hydrocarbon to an unsaturated hydrocarbon coin rising a chloride inorganic catalyst support, palladium, and silver. The catalyst may comprise from about 10 to about 1200, alternatively from about 20 to about 800 ppm by weight of chlorine; from about 0.01 to about 1.0, alternatively from about 0.01 to about 0.8 weight percent palladium based on a total weight of the catalyst; and (c) from about 0.01 to about 10, alternatively from about 0.01 to about 5 weight pecan silver based on a total weight of the catalyst The catalyst may feather comities one or more selectivity enhancers selected from the group consisting of iodine, iodide compounds, phosphorus, phosphorus compounds, slur, sulfur conjoins, alkaline metals, alkaline metal surrounds, and combinations thereof The catalyst may coir rise from about 0.001 to

about 10 weight percent selectivity enhancer based on a total weight of the catalyst. The chloride inorganic catalyst support may have a surface area of from about 2 to about 100 m^/g.
DESCRIPTION OF THE DRAWINGS
The invention, together with further advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings in which:
Figure 1 depicts a process flow diagram of an embodiment in which an unsaturated hydrocarbon stream containing a highly unsaturated hydrocarbon is fed to a hydrogenation reactor for selective hydrogenation of the highly unsaturated hydrocarbon to amonoolefin.
Figure 2 is a graph illustrating the relative fouling curves during the hydrogenation of acetylene for one control selective hydrogenation catalyst and two selective hydrogenation catalysts comprising palladium on an inorganic catalyst support modified by a chlorine-containing compound
Figure 3 is a graph illustrating the relative catalyst selectivity to ethylene during the hydrogenation of acetylene for one control selective hydrogenation catalyst and two selective hydrogenation catalysts palladium on an inorganic catalyst support modified by a chlorine-containing
DETAILED DESCRIPTION OF THE INVENTION
In an embodiment, a method of making a catalyst for selectively hydrogenating highly unsaturated hydrocarbons to unsaturated hydrocarbons comprises contacting an inorganic catalyst support with a chlorme-contaiaing

compound to create a clilorided catalyst support. In an embodiments, the chlorine-containing confound is a gas, a liquid, or combinations thereof Palladium is subsequently added to the chlorided catalyst support to create a supported-palladium coiqposition useful as a. selective hydrogenation catalyst. A suitable selectivity enhancer may be optionally added to the supported-palladium composition thereby creating an enhanced supported-palladium coin position that is effective as a selective hydrogenation catalyst.
The details of such methods are provided below. As used herein, a highly unsaturated hydrocarbon is defined as a hydrocarbon containing at least one triple bond, conjugated carbon-carbon double bond, or cumulative carbon-carbon double bond As used herein, an unsaturated hydrocarbon is defined as a containing an isolated carbon-carbon double bond Examples of highly unsaturated hydrocarbons include without limitation acetylene, methyl acetylene and procaine. Examples of unsaturated hydrocarbons include ethylene and propylene. It is also understood that the term "catalyst" refers to the support together with the materials impregnated in or on the support.
Unless specified to the contrary or apparent from the plain meaning of a phrase, the word "or" has the inclusive meaning.
In some embodiments, the catalyst support may comprise an inorganic support such as one or more aluminums, silica’s, titanium, zirconia’s, aluminosilicates (such as clays and/or zeolite), spinals (such as zinc alumdnate, zinc titanate, and/or magnesium aluminate), or combinations thereof In some embodiments, a suitable catalyst support is an alpha (a)-lamina support.

A catalyst support having a surface area of from about 2 to about 100 square meters per gram (mug) may be einployed. Alternatively the support may have a surface area of from about 2 to about 75 m /g, or from about 3 to about 50 mVg. The surface area of the support may be determined using any method known to one of ordinary skill in the art, alternatively using the well-known method of Brinier, Emmett, and Teller ("BET") by measuring the quantity of nitrogen adsorbed on the catalyst. Alternatively, it can also be measured by mercury intrusion. A suitable mercury intrusion method is described in ASTM UOP 578-02, entitled "Automated Pore Volume and Pore Size Distribution of Porous Substances by MERCURY Proximity," which is incorporated herein by reference in its entirety.
Particles of the catalyst support generally have an average diameter of from about 1 to about 10 nM, alternatively from about 2 to about 6 mm, and can have any suitable shape. In an erobodiment, the shape of the catalyst support may be cylindrical In an alternative enibodiment, the catalyst support may be spherical.
Initially, the inorganic catalyst support is contacted with a chlorine-containing to create a chlorided catalyst support The chlorine-containing compound can be a gas, a Quid, or combinations thereof An embodiment contacting the inorganic catalyst support with a liquid chlorine-containing to create a chlorided catalyst support Such a liquid may surprise at least one chlorine-containing In some embodiments the Quid chlorine-containing compounds to which the inorganic catalyst support may be to create the chlorided catalyst support include, but are not limited to, hydrochloric acid; alkaline metal chloride; alkaline earth chloride; chlorohydrocarbons; cornpones described by

the formula N(HvRwRVR"yR'" Cl, where R, R', R", and R'" is methyl, ethyl, propyl, butyl, or any combination thereof and v, w, x, y, z can be 0 to 4 provided v+w+x+y+z = 4; or combinations thereof In some embodiments, the alkaline metal chloride may comprise potassium chloride, sodium chloride, lithium chloride, or combinations thereof In some embodiments, the alkaline earth chloride may coin rise calcium chloride, barium chloride, or combinations thereof In some embodiments,
compounds described by the formula N(HvRwR'xR"y' "'z)' comprise ammonium chloride, methyl ammonium chloride, tetramethylammonium chloride, tetraethylammonium chloride, or originations thereof Chloral-hydrocarbons as used herein may comprise compounds containing 1-10 carbons wherein there is at least one substitution of hydrogen for chlorine. In some embodiments chloral-hydrocarbons surprise compounds described by the formula CClxHy (where x + y = 4); compounds described by the formula C2ClxHy (where x + y = 6); or combinations thereof In some embodiments confounds described by the formula CClxHy comprise carbon tetrachloride, dichloromethane, or carbonations thereof In some embodiments, conjoins described by the formula CClxHy comprise dichloromethane. In an enibodiment, the liquid chlorine-containing compound surprises potassium chloride in solution.
The inorganic catalyst support can be contacted with the liquid chlorine-containing surround in any suitable Maier that will yield a selective hydrogenation catalyst meeting the parameters described herein. In an embodiment, the method used to contact an inorganic catalyst support with a liquid chlorine-containing coin pound may be incipient wetness rogation, which is well known in the art. During

incipient wetness impregnation, the pores of the support become substantially filled with the hquid chlorine-containing conipound. Other contacting methods such as soaking may also be employed to contact the inorganic catalyst support with tiled liquid chlorine-containing coinpound to create a chlorided catalyst support.
An alternative embodiment initially contacting tie inorganic catalyst with a gaseous chlorine-containing compound to create a chlorided catalyst support. In some embodiments, the chlorine-containing confounds that may be ercpbyed as gases include, but are not limited to, hydrogen chloride gas, chlorine gas, CClxHy (where x + y = 4), C2ClxHy (where x + y = 6), or continuations thereof In another embodiment, the gaseous chlorine-containing confounds are obtained by heating a volatile chore-hydrocarbon or mixture thereof
A method used to contact an inorganic catalyst support with a gaseous chlorine-containing coupon may be cacti plashed by heating the inorganic catalyst support in the presence of a gaseous chlorine-containing compound and optionally in the presence of oxygen, water, nitrogen, hydrogen or mixtures thereof to create a chlorided catalyst support. In an embodiment, the inorganic catalyst support may be contacted with a gaseous chlorine-containing corn pound at tertiparatures of from about 300°C to about 850°C for from about 0.2 to about 20 hours.
The amount of chorine-containing compound deposited on the inorganic support is controlled independently of the contact method, whether by liquid contacting, gas phase contacting, or combination thereof The contacting method may deposit an amount of chlorine-containing confound such that the chlorided catalyst support, ie., the catalyst support after exposure to a chlorine-containing compound,

comprises from about 20 to about 0.001 weight percent clitorises based on a total weight of the chlorided catalyst support, alternatively from about 10 to about 0.001 weight precut chlorine, alternatively from about 2 to about 0.001 weight percent chlorine.
After the inorganic catalyst support has been contacted with the chlorine-containing coir pound to create the chlorided catalyst support, the clilorided catalyst support may be removed from contact with the chlorine-containing conpound and processed to remove from the chlorided catalyst support unwanted elements such as an amount of chlorine-containing conpound, decomposition products thereof, or other unwanted elements to create a clean chlorided catalyst support and otherwise prepare the chlorided catalyst support for exposure to palladium. Removing an amount of chlorine-containing and/or any other unwanted elements may occur via a wash, via vaporization, or combinations thereof, depending, for exoxnple, on the type of chlorine-containing compound involved. The vaporization may be acconpHshed at a tercperature of from about 300°C to about 850°C for from about 0.2 to about 20 hours. After processing, the clean chlorided catalyst support may comprises from about 5 to about 2000 ppm by weight of chlorine; alternatively, may comprise from about 10 to about 1200 ppm by weight of chlorine; alternatively, from about 20 to about 800 ppm by weight of chlorine; alternatively, from about 30 to about 400 ppm by weight of chlorine with respect to the support.
In an embodiment, a chlorided catalyst support produced by contact with a hquid chlorine-containing conpound may be exposed to an elevated temperature of from about 50 °C to about 850 °C for from about 0.5 to about 20 hours to dry and/or

cline the chlorided catalyst support, thereby producing a cleaned chlorided catalyst support. In some embodiments, an optional washing step may follow the exposure to an elevated temperature. For sextuple, the may be washed with water at of from about 20 °C to about 100 °C for from about 1 minute to about 2 hours. In an embodiment, the washing utilizes boiling distilled or deionized water and occurs after drying and/or calcining. Following the washing step, the chlorided catalyst support may optionally undergo another exposure to an elevated temperature of from about 50 °C to about 900 °C for from about 0.5 to about 20 hours to remove any unwanted moisture.
In another einbodiment, a chlorided catalyst support produced by contact with a gaseous chlorine-containing may be cleaned via vaporization or washing or a combination thereof to remove an amount of chlorine containing compound, decoirposition products thereof, or other unwanted elements. In an embodiment, after contacting the inorganic catalyst support with the gaseous chlorine-containing confound, flow of the gaseous chlorine containing compound is stopped, and the gaseous treated chlorided catalyst support may be continued to be heated and/or acclaimed by exposure to an elevated tenperature in the absence of the gaseous chlorme containing compound to produce a cleaned chlorided catalyst support. Exposure to an elevated may occur in the presence of oxygen, water, nitrogen and mixtures thereof for less than or equal to about 18 hours. This vaporization removal step may be optionally followed by exposing the chlorided catalyst support with a heated stream of gas free of the chlorine containing compound to further remove any unwanted elements. After processing, the cleaned chlorided

catalyst support may comprise from about 5 to about 2000 ppm by weight of chlorine; alternatively, may coin rise from about 10 to about 1200 ppm by weight of chlorine; alternatively, from about 15 to about 800 ppm by weight of chlorine; alternatively, from about 15 to about 400 ppm by weight of chlorine with respect to the support.
Next, palladium may be added to the clean chlorided catalyst support to create a supported-palladium composition. Addition of the palladium may be accomplished by contacting the support with a palladium-containing solution comprising palladium metal or a palladium containing compound such as palladium chloride or palladium nitrate using any suitable manner that will yield a selective hydi'ogenation catalyst meeting the parameters described herein. In an embodiment^ the palladium-containing solution is an aqueous solution. In an embodiment, the method used to contact a clean chlorided catalyst support with a palladium-containing solution may be incipient wetness impregnation, which is well known in the art. The palladium-containing solution may contain a sufficient amount of palladium to form a supported-palladium having from about 0.01 to about 1.0 weight percent palladium, alternatively from about 0.01 to about 0.8 Wight percent palladium, alternatively from about 0.01 to about 0.5 weight percent palladium, all weight percentages being by weight of the supported-palladium composition. In an embodiment, the palladium-containing solution is added to the clean chlorided catalyst support in a manner to cause at least about 95 weight percent of the supported-palladium composition particles to have the palladium concentrated near the periphery of the supported-palladium composition particles such that those particles have a so-called palladium skin.

As used herein, the term "palladium skin" refers to a peripheral layer of the exported-palladium composition that contains at least about 95 weight percent of the palladium incorporated in the support The palladium slunk can be any thickness as long as such thickness can promote the hydrogenation process disclosed herein. Generally, the thickness of the palladium skin can be in the range of from about 1 micron to about 3000 microns, alternatively from about 5 microns to about 2500 microns, alternatively from about 5 microns to about 2000 microns. For further reference, the teachings of U.S. Pat Nos. 4,404,124 and 4,484,015 are instructive and are incorporated by reference herein.
Suitable methods for determining the concentration of the palladium in the skin of the supported-palladium composition are known in the art. Determining the concentration of the palladium in the skin of the supported-palladium composition helps in detonating the thickness of the skin. One technique that may be employed to determine the palladium skin thickness is the electron microprobe method. Another technique involves breaking open a representative sample of the supported-palladium particles and treating the supported-palladium composition particles with a dilute alcoholic solution of N,N-dimethyl-para-nitrosoa2flline. The treating solution reacts with the palladium to give a red color that can be used to evaluate the distribution of the palladium Yet another technique for measuring the concentration of the palladium in the skin of the supported-palladium compositions involves breaking open a representative sanple of catalyst particles, followed by treating the particles with a reducing agent such as hydrogen to change the color of the skin and thereby evaluate the distribution of the Palladian

The supported-palladium corn position formed by contacting the clean chlorided catalyst with the palladium-containing solution optionally may be dried at a temperature of from about 25 °C to about 150 C for a period of from about 0.5 hour to about 20 hours to produce a selective hydrogenation catalyst. The supported-palladium composition described above may optionally be further claimed at a tenperature of from about 200 °C to about 850 °C for a period of from about 0.2 to about 20 hours.
In aa alternate embodiment, one or more selectivity enhancers may be added to the supported-palladium composition to produce an enhanced supported-palladium composition useful as a selective hydrogenation catalyst. In one embodiment, this addition can occur by soaking the supported-palladium composition in a liquid composing one or more suitable selectivity enhancers. In another embodiment, this addition can occur by incipient wetness rogation of the supported-palladium composition with liquid con:5)rising one or more suitable selectivity enhancers. This additional step may be optionally followed by again drying and/or calcining the enhanced sis -palladium corn position as described above to produce an enhanced supported-palladiiun composition useful as a selective hydrogenation catalyst.
In an embodiment, suitable selectivity enhancers include, but are not limited to, Group IB metals, Group IB metal compounds, phosphorus, sulfur, phosphorus coir pounds, sulfur compounds, alkaline metals, alkaline metal compounds, iodine, iodide coir pounds, or combinations thereof In an embodiment, the selectivity enhancer con:5)rises silver (Ag), silver corn pounds, iodine, iodine compounds, or

combinations thereof For example, silver in the form of a silver compound such as silver nitrate may be added to the supported-palladium composition.
In an erobodiment the resulting enhanced supported-palladium composition may comprise from about 0.001 weight percent to about 10 weight percent of the selectivity enhancer, alternatively from about 0.01 weight percent to about 5 weight percent selectivity enhancer, alternatively from about 0.01 weight percent to about 2 weight percent selectivity enhancer, all weight percentages being based on a total weight of the enhanced supported palladium
In an alternative embodiment the resulting enhanced supported-palladium may comprise from about 0.01 weight percent to about 10 weight percent silver, alternatively from about 0.01 Wight percent to about 5 weight percent silver, alternatively from about 0.01 weight percent to about 2 weight percent silver. In a further embodiment, lie resulting enhanced supported-palladium composition may coin rise from about 0.001 weight percent to about 10 weight percent iodine, alternatively from about 0.01 weight percent to about 5 weight percent iodine, alternatively from about 0.01 weight percent to about 2 weight percent iodine.
In an embodiment, iodine may optionally be added to the enhanced supported-palladium corn position in addition to silver using a number of techniques, e.g., incipient wetness irrigation or soaking, and the support may again be dried and/or claimed to produce an enhanced supported-palladium composition useful as a selective hydrogotiation catalyst. Iodine may be added simultaneously with the silver, or sequentially before or after the silver. The concentration of iodine in the resulting selective hydrogenation catalyst may range from about 1 ppm to about 1,000 ppm by

weighty alternatively from about 1 ppm to about 800 ppm by weight, alternatively from about 1 ppm to about 500 ppm by weight all ppm by weight being based on a total weight of the enhanced supported palladium composition. In some embodiments, the suitable iodine-containing materials include, but are not hinted to, elemental iodine, ammonium iodide, potassium iodide, tetraalkylammonium iodide (e.g., tetramethylammonium iodide and tetraethylammonium iodide), potassium iodate, ammonium iodide, or combinations thereof The resulting selective hydrogenation catalyst can be dried and/or calcite prior to using the selective hydrogenation catalyst in the hydrogenation process. In some embodiments, this draying step can be carried out at a in the range of from about 25 to about 150"C for a period of from about 0.5 hour to about 20 hours. In some embodiments, this calciniag step can be carried out at tenperatures up to about 850°C, e.g., in the range of from about 150'*C to about 700°C, for a period of from about 0.2 to about 20 hours.
In some embodiments, the one or more selectivity enhancers can be distributed throughout the enhanced supported-palladium using methods known to those skilled ia the art. In an embodiment, the supported-palladium composition particles can be placed in an aqueous silver nitrate solution of a quantity greater than that necessary to fill the pore volume of the particles. The resulting enhanced supported-palladium may be dried and/or claimed to decompose the silver-containing before using the enhanced supported-palladium composition as a catalyst in the selective hydrogenation process. In some embodiments, this drying may be performed at a terrperature in the range of from

about 25°C to about 150°C for a period of from about 0.5 to about 20 hours. In some embodiments^ this calcining step may be performed at temperatures up to about 850^*0, e.g., in the range of from about 150°C to about 750°C, for a period of from about 0.2 to about 20 hours.
Optionally, the drying or calcining may be followed by a reduction step to reduce the metals (e.g., catalytic metals) in the enhanced supported-palladium conapositiou This reduction step may be accomplished in a variety of ways, all well known in the art. One embodiment comprises reducing the enhanced supported-palladium using hydrogen gas or a hydrogen gas containing feed, e.g.,, the feed stream of the selective hydrogenation process, to reduce the catalytic metals, thereby providing for optimum operation of the selective hydrogenation process. Such a gaseous hydrogen reduction may be carried out at a temperature vi the range of from, for about 25°C to about 450°C.
In an embodiment, a selective hydrogenation catalyst compositions formed in accordance with the method described above comprises an a-lamina support treated with a chlorine-containing conpound, palladium, and optionally at least one selectivity enhancer, e.g., silver and/or iodine. Further, such a selective hydrogenation catalyst may can’s a support having a surface area of from about 2 to about 100 square meters per gram (mVg); alternatively from about 2 to about 75 mVg, or from about 3 to about 50 m^/g.
In some embodiments, methods of using the previously described selective hydrogenation catalysts, for example in a selective hydrogenation process, currieries contacting an unsaturated hydrocarbon stream primarily containing an unsaturated

hydrocarbon, e.g., ethylene, but also containing a highly unsaturated hydrocarbon, e.g., acetylene, with such catalyst compositions. The contacting may be executed in the presence of hydrogen at conditions effective to selectively hydrogenate the highly unsaturated hydrocarbon to an unsaturated hydrocarbon. In an embodiment, the selective hydrogenation catalysts of this disclosure are used in the hydrogenation of highly unsaturated hydrocarbons such as for example and without limitation acetylene, methyl acetylene, procaine or combinations thereof
Figure 1 illustrates an embodiment of a hydrogenation process that utilizes a selective hydrogenation catalyst made in the manner described above. The hydrogenation process includes feeding an unsaturated hydrocarbon stream 10 and a hydrogen (H2) stream 20 to a hydrogenation reactor 30 within which the selective hydrogenation catalyst is disposed. The unsaturated hydrocarbon stream 10 primarily comprises one or more unsaturated hydrocarbons, but it also contains one or more highly unsaturated hydrocarbons such as for example and without imitation acetylene, methyl acetylene and procaine. Alternatively, unsaturated hydrocarbon stream 10 and hydrogen stream 20 may be combined in a single stream (not shown) that is fed to hydrogenation reactor 30. Accordingly, unsaturated hydrocarbon stream 10 may con:5)rise hydrocarbons, including one or more unsaturated hydrocarbons such as ethylene and one or more highly unsaturated hydrocarbons such as acetylene, methyl acetylene and procaine.
In an embodiment, reactor 30 is a selective hydrogenation reactor that may belong to an acetylene removal unit of an unsaturated hydrocarbon production plant in a backend configuration. As used herein, 'lacked" refers to the location of the

acetylene removal unit in an unsaturated hydrocarbon production unit that receives tithe lower boiling fixation from a deethanizer fractionation tower that receives the higher boiling fraction from a demethanizer fractionation tower that receives a feed from an unsaturated hydrocarbon production process.
In an embodiment, reactor 30 is a selective hydrogenation reactor that may belong to an acetylene removal unit of an unsaturated hydrocarbon production plant in a frontend deethanizer configuration. As used herein, "front end deethanizer" refers to the location of the acetylene removal unit in an unsaturated hydrocarbon production unit that receives the lower booing fraction from a deethanizer fractionation tower that receives a feed from an unsaturated hydrocarbon production process.
In an embodiment, reactor 30 is a selective hydrogenation reactor that may belong to an acetylene removal unit of an unsaturated hydrocarbon production plant in a frontend depropanizer configuration. As used herein, "frontend depropanizer" refers to the location of the acetylene removal unit in an unsaturated hydrocarbon production unit that receives the lower boiling fraction from a depropanizer fractionation tower that receives a feed from an unsaturated hydrocarbon production process.
In an embodiment, reactor 30 is a selective hydrogenation reactor that may belong to an acetylene removal unit of an unsaturated hydrocarbon production plant in a raw gas configuration. As used herein, *'raw gas" refers to the location of the acetylene removal unit in an unsaturated hydrocarbon production unit that receives a feed from an unsaturated hydrocarbon production process without any starveling hydrocarbon fractionation.

It is understood that hydrogenation reactor 30, and likewise the selective hydrogenation catalysts disclosed herein, is not limited to use in backend acetylene removal units, frontend deethanizer units, frontend depropanizer, or raw gas units and may be used in any process wherein a higlily unsaturated hydrocarbons contained within an unsaturated hydrocarbon stream is selectively hydrogenated to a unsaturated hydrocarbon.
In those embodiments wherein the acetylene removal unit is in a backend configuration, the highly unsaturated hydrocarbon being fed to the hydrogenation reactor 30 conqjrises acetylene. The mole ratio of the hydrogen to the acetylene being fed to hydrogenation reactor 30 may be in the range of from about 0.1 to about 10, alternatively from about 0.2 to about 5, alternatively from about 0.5 to about 3.
In those embodiments wherein the acetylene removal unit is in a front end deethanizer, front-end depropanizer or raw gas configuration, the highly unsaturated hydrocarbon being fed to the hydrogenation reactor 30 con:5)rises acetylene. In such an embodiment, the mole ratio of the hydrogen to the acetylene being fed to the hydrogenation reactor 30 may be in the range of from about 10 to about 3000, alternatively from about 10 to about 2000, alternatively from about 10 to about 1500. •
In those embodiments wherein the acetylene removal unit is in a front-end depropamzer or raw gas configuration, the highly unsaturated hydrocarbon being fed to the hydrogenation reactor 30 methyl acetylene. In such an embodiment, the mole ratio of the hydrogen to the methyl acetylene being fed to the hydrogenation reactor 30 may be in the range of from about 3 to about 3000, alternatively from about 5 to about 2000, alternatively from about 10 to about 1500.

In those embodiments wherein the acetylene removal unit is in a front-end depropanizer or raw gas configuration, the highly unsaturated hydrocarbon being fed to the hydrogenation reactor 30 comprises procaine. In such an embodiment, the mole ratio of the hydrogen to tile procaine being fed to the hydrogenation reactor 30 may be in the range of from about 3 to about 3000, alternatively from about 5 to about 2000, alternatively from about 10 to about 1500.
In another embodiment, reactor 30 may represent a plurality of reactors. The plurality of reactors may optionally be separated by a means to remove heat produced by the reaction. The plurality of reactors may optionally be by a means to control inlet and effluent flows from reactors or heat removal means allowing for individual or alternatively groups of reactors within the plurality of reactors to be regenerated The selective hydrogenation catalyst may be arranged in any suitable configuration within hydrogenation reactor 30, such as a fixed catalyst bed
Carbon monoxide may also be fed to reactor 30 via a separate stream (not shown), or it nay be combined with hydrogen stream 20. In an enibodiment, the amount of carbon monoxide being fed to reactor 30 during the hydrogenation process is less than about 0.15 mol% based on the total moles of fluid being fed to reactor 30.
Hydrogenation reactor 30 may be ulcerated at conditions effective to selectively hydrogenate highly unsaturated hydrocarbons to one or more unsaturated hydrocarbons upon contacting the selective hydrogenation catalyst in the presence of the hydrogen. The conditions are desirably effective to maximize hydrogenation of highly unsaturated hydrocarbons to unsaturated hydrocarbons and to minimize hydrogenation of highly unsaturated hydrocarbons to saturated hydrocarbons. In

some embodiments, acetylene may be selectively hydrogenated to ethylene. Alternatively methyl acetylene may be selectively hydrogenated to ethylene; alternatively procaine may be selectively hydrogenated to propylene. In some embodiments, the temperature within the hydrogenation zone may be in the range of from about 5°C to about 300'C, alternatively from about to about 250°C, or from about 15°C to about 200°C. In some embodiments, the pressure within the hydrogenation zone may be in the range of from about 15 (204 kPa) to about 2,000 (13,890 kPa) pounds per square inch gauge (psig), alternatively from about 50 psig (446 kPa) to about 1,500 psig (10,443 kPa), or from about 100 psig (790 IcPa) to about 1,000 psig (6,996 kPa).
Referring back to Figure 1, an effluent stream 40 comprising unsaturated hydrocarbons, including the one or more mongolisms produced in hydrogenation reactor 30, and any unconverted reactants exit hydrogenation reactor 30. In an enibodiment, effluent stream 40 primarily comprises ethylene and contains less than about 5 ppm, desirably less than about 1 puma highly unsaturated hydrocarbons.
The selective hydrogenation catalyst contained in hydrogenation reactor 30 may be regenerated as needed. In some embodiments, regeneration of the selective hydrogenation catalyst may be by optionally stream stripping the selective hydrogenation catalyst then calcining the catalyst in the presence of a gas oxygen at a not in excess of about 500'*C to bum off any organic matter, polymer, or char.

EXAMPLES
The invention having been generally described, the following example exemplifies embodiments of the invention and demonstrates the practice and advantages thereof It is understood that these externals are given by way of illustration and are not intended to limit the specification or the following claims in any manner. All numerical values are approximate. When numerical ranges are given, it should be understood that embodiments outside tile stated ranges may suit fall within the scope of the invention. Specific details described in each example should not be construed as necessary features of ties invention.
In the following examples, the amount of green oil produced by each selective hydrogenation catalyst was calculated as follows:
weight % green oil = final catalyst weight - initial catalyst weight)/initial catalyst weighty days on stream)* 100 Further, the selectivity (seL) to ethylene was also calculated using the following set of equations, where "C4" represents butane, butanes and butadiene and where 'leaves" refer to hydrocarbons having more carbon atoms than C4:
selectivity to ethane = (weight of ethane made/weight of acetylene consumed)* 100 selectivity to C4's = (weight of C4's made/weight of acetylene consumed)*100 selectivity to heavies = (weight of heavies made/weight of acetylene consumed)*100 selectivity to ethylene = 100 -• seL to ethane - seL to C4's - seL to heavies The fouling rate was determined by plotting reaction temperature, while maintaining the acetylene conversion at 90%, as a function of time for each sample and then taking the slope of that line. A selectivity comparison was also made by plotting

the selectivity to ethylene at 90% acetylene conversion as a fiction of time for each sanple and then integrating the curve from 0 to 200 hours. Table 1, below, shows these fouling rate and selectivity area values flier 200 hours on stream. The area values represent the results of integrating the selectivity curves from 0 to 200 hours.
In the following examples, the amount of chlorine on the chlorinated inorganic support, the selective hydrogenation catalyst or any intennediate product was determined by x-ray spectroscopic methods. In this method samples were pulverized in a ball mill and pressed into a 31 mm disk. X-Ray Florescence data (XRF) was collected The concentrating of chorine was determined using a standard less analysis software package. All concentrations are semi quantitative.
EXAMPLE 1
The following example illustrates the preparation of various palladium-containing selective hydrogenation catalyst san:5)les, and the use of the samples in a selective hydrogenation process.
Catalyst A (control) was prepared on a-Al203 pellets supplied by Sid Chemie of Louisville, Kentucky, USA in the form of 4mm x 4mm tablets as described in U. S. Pat No. 4,484,015. The a-Altos pellets had a surface area of about 5 to about 7 mVg (determined by the BET method N2). Catalyst A contained 0.02 weight percent palladium and 0.12 weight percent silver and 99 weight percent AI2O3.
Catalyst B was prepared as foods: an aqueous solution of about 1.13g NH4CI in about 16g distilled water was added to about 50g of a-Haps pellets (4mm x 4mm, surface area of about 5 to about 7 mVg, provided by Slid Chemie of Louisville,

Kentucky, USA) followed by drying at about 125°C for about 1 ho\ir. The support was then claimed at about 538°C for about tire hours in air. Next about 0.02 weight percent palladium and about 0.12 weight percent silver were added as described in U.S. Pat No. 4,484,015.
Catalyst C was prepared as follows; an aqueous solution of about 7.49g Kill in about 92 g distilled water was added to about 325g of a- AI2O3 pellets (4mm x 4mm, surface area of about 5 to about 7 mVg, provided by Sid Chemie of Louisville, Kentucky, USA) followed by drying at about 125°C for about 1 hour. The support was then calcite at about 850°C for about 2 hours in air. The support was lien washed repeatedly with boiling distilled water until the wash solution gave a negative chlorine test with an about IM Agony sedition. The subsequent was dried at about 125°C for about 1 hour and claimed at about 538^C for about 3 hours. Next about 0.02 weight percent palladium (Pd) and about 0.12 weight percent silver (Ag) were added as described in U.S. Pat No. 4,484,015.
Reactor runs with each of the above catalysts, A through C, were made under laboratory test conditions. Laboratory test conditions are performed in the following manner: about 20 mL of catalyst was mixed with about 40 mL of 14 grit landmine and placed in a stainless steel jacketed reactor tube having an inner diameter of about 0.62 inch (15.7 nun) and a length of about 18 inches (457 mm). The reactor had a 3/16" thermo well running the length of the catalyst bed in the center of the reactor. The catalyst bed resided trio the middle of the reactor and both ends of the reactor were packed with about 40 mL of launder. The reaction teirperature was controlled by circulating ethylene glycol through the jacket of the reactor tube. The catalyst was then

activated with hydrogen at a flow rate of about 200 mL/min at atmospheric pressurize at 170T (77°C) for two hours.
Next, the catalyst was contacted with a feed gas comprising approximately 13 weight percent multilane, 85.8 weight percent ethylene, 1.2 weight percent acetylene, at a flow rate of about 913 mL/min at about 200 psig (1480 kPa). Hydrogen was added to give an about 1.3 molar ratio of hydrogen to acetylene. The reaction tenperature was adjusted to yield an acetylene conversion of about 90%. Conversion is referred to as the disappearance of acetylene. Gas analyses woe-e performed by gas chromatography using an AI2O3 plot column. Selectivity’s were calculated on a weight basis.
Table I, below, contains pertinent data regarding the predominance of the catalysts, A through C, described above.

As indicated by the data in Table 1, contacting an inorganic catalyst support with a chlorine-containing conpound increases the selectivity to ethylene among selective hydrogenation catalysts comprisal palladium Catalysts B and C, each modified by contacting with either NH4CI or KCl, both demonstrate significantly higher selectivity’s to ethylene ordered to control catalyst A In addition, the foul rate for catalysts B and C is lower than that of the control catalyst. In addition, green oil production is reduced.

EXAMPLE 2 Figure 2 illustrates relative foul curves in degrees Fahrenheit per hour (°F/hour) for one control selective hydrogenation catalyst A, and two catalysts prepared in accordance with the methods described herein for use in an otherwise typical hydrogenation process (selective hydrogenation catalysts B and C). Line 200 tracks reactor temperature over time for a reactor run made with the control Catalyst A. Catalyst A is a selective hydrogenation catalyst corn rising palladium/silver supported on an AI2O3 support. Line 210 tracks reactor temperature over time for a reactor run made using Catalyst B, which is a selective hydrogenation catalyst corcprisiug palladium/silver supported on a chlorided catalyst support produced using ammonium chloride as the chlorine-containing conpound Line 220 tracks reactor temperature over time for a reactor run made using Catalyst C, which is a selective hydrogenation catalyst comprising palladium/silver supported on a chlorided catalyst support produced using potassium chloride as the chlorine-containing conpound The fouling rate related to line 200 is about 0.17 degrees Fahrenheit per hour. The fouling rate indicated by line 210 is about 0.07 degrees Fahrenheit per hour, and the fouling rate indicated by line 220 is about 0.14 degrees Fahrenheit per hour. Thus, the fouling rate demonstrated by the selective hydrogenation catalysts comprising inorganic catalyst supports modified by chlorine-containing compounds (hue 210 and 220) are reduced relative to the control catalyst. The lower fouling rates related by line 210 and 220 are also associated with a reduction in green oil generation when compared to the control catalyst (200). The fouling rate for a selective hydrogenation catalyst as described herein may be, for example, at least about 25 percent less, at least about 50 percent less, or at least about

80 percent less than a fouling rate of the same catalyst when not contacted witli a* chlorine-containing compound and run under control conditions.
EXAMPLE 3
For the selective hydrogenation catalysts and reactor runs described in Example 2, Fig. 3 illustrates relative data for selectivity to ethylene. Line 300 tracks selectivity to ethylene over time of the control catalyst A. Lines 310 and 320 track the selectivity to ethylene over time of the catalysts comprising palladium and a support modified by a chlorine-containing coinpound (Catalysts B and C). The selectivity for ethylene indicated by line 310 and 320 are greater relative to the selectivity indicated by the control catalyst (line 300). Furthermore, the selectivity represented by line 310 and 320 is more stable over time than line 300, The percent selectivity improvement may be based on the integrated area under the selectivity versus time curve in Fig. 3 as shown in Table 1.
As a result of improvements in fouling rate, green oil production, and selectivity to unsaturated hydrocarbons, the life of the selective hydrogenation catalyst is extended such that the catalyst requires regeneration less often, resulting in lower operating costs of the hydrogenation process.
EXAMPLE 4
The following example illustrates the application of the catalyst in a front-end depropanizer reactor process. Hydrogenation runs were made with 20 cc of the previously described catalysts. The catalysts were placed in a stainless steel reactor tube having a 0.62 inch inner diameter and a length of about 18 inches. The catalyst resided in the middle of the reactor, and both ends of the reactor were packed with 10

mL of launder The catalyst was reduced at about 100°F for about 1 hour under hydrogen gas flowing at 200 nil/min and at 200 pounds per square inch gauge (psig). A feed stream typical of a feed from the top of a de-procaine fractionation tower in an ethylene plant was prepared, except that the ethane and propane were replaced with methane to aid in the selectivity calculations. The feed stream contained approximately (all by weight unless otherwise noted): hydrogen 2.5%; methane 40%; ethylene 41%; propylene 15%; acetylene 3500 ppm procaine 1800 ppm; methyl acetylene 1600 ppn and carbon monoxide 23 0 ppm (by volume). The feed stream was introduced into the reactor at a flow rate of 900 mL per minute at 200 psig translating to a gas hourly space velocity of about 2700 hour-1. The reactor tenperature was increased until the hydrogenation reaction ran away, ie., the uncontrollable hydrogenation of ethylene was allowed to occur. The reactor was then allowed to cool to room temperature before data collection was started
Feed at 900mL/min and 200 psig was passed over the catalyst while holding the temperature constant before the exit stream by gas chromatography. The catalyst was determined by inserting a thermocouple into the thermo well and varying its position until the highest was observed The fumace was then raised a few degrees, and the testing cycle was repeated until 3 weight % of ethane was produced
A of catalyst B was tested using the above protocol as wet as a control sample (catalyst A), the results are presented in Table 2. The results indicate that catalyst B has a higher MAPD conversion and a higher ethylene selectivity than the

control catalyst at the same reaction tenperatoe. Furthermore catalyst B has a similar to higher acetylene conversion at the same temperatures.

While embodiments of the invention have been shown and described, modifications thief can be made by one skilled in the art without departing from the spirit and teachings of the invention. The embodiments described herein are exemplary only, and are not intended to be smiting. Many variations and modifications of the invention disclosed herein are possible and are within the scope of the invention. Where numerical ranges or limitations are expressly stated, such actress ranges or limitations should be understood to include iterative ranges or Imitations of like magnitude falling within the expressly stated ranges or limitations (e.g., from about 1 to about 10 includes, 2, 3, 4, etc.* greater than 0.10 includes 0.11, 0.12, 0.13, etc.). Use of the term "optionally" with respect to any element of a claim is intended to mean that the subject element is required, or alternatively, is not required Both alternatives are inside to be within the scope of the claim. Use of broader terms such as corpuses, includes, having, etc. should be understood to provide support for narrower terms such as consisting o consisting essentially of, substantially of, etc.
Accordingly, the scope of protection is not Muted by the description set out above but is only limited by the claims which follow, that scope including all

equivalents of the subject matter of the claims. Each and every claim is incorporated into the specification as an embodiment of tie present invention. Thus, the claims are a feather description and are an addition to the embodiments of the present invention. The disclosures of all patents, patent applications, and publications cited herein are hereby incorporated by reference, to the extent that they provide , procedural or other details supplementary to those set forth herein.

CLAIMS:
1. A method of producing a selective hydrogenation catalyst corn rising:
(a) contacting an inorganic catalyst support with a chlorine-containing compound to form a chlorided catalyst support; and
(b) adding palladium to the chlorided catalyst support to form a supported-palladium composition,

2. The method of claim 1, wherein the chlorine-containing composite comprises hydrochloric acid, an alkaline metal chloride, an alkaline earth chloride, chlorohydrocarbons, or combinations thereof
3. The method of claim 1, wherein the chlorine-containing conjoined con:5)rises a confound described by the formula N(HvRwR'xR"yR'" Cal; where R, R', R", and R'" is methyl, ethyl, propyl, butyl, or any combination thereof; and each of v, w, x, y, 2 can be 0 to 4 provided that v+w+x+y+z == 4.
4. The method of claim 1, wherein the chlorine-containing compound conprises a confound described by the formula CClxHy, wherein x + y = 4.
5. The method of claim 1, wherein the chlorine-containing a compound described by the formula C2ClxHy, wherein x + y = 6.
6. The method of claim 1, wherein the chlorine containing compound conprises potassium chloride, sodium chloride, thrum chloride, calcium chloride, barium chloride, ammonium chloride, methyl ammonium chloride, tetramethylammonium chloride, tetraethyl ammonium chloride, carbon tetrachloride, tricolors ethane, or combinations thereof

7. The method of claim 1, further comprising cleaning the chlorided catalyst support to produce a clean chlorided catalyst support having from about 5 to about 2000 ppm by weight chlorine.
8. The method of claim 1, wherein the selective hydrogenation catalyst con:55rises from about 0,01 to about 1.0 weight percent palladiums based on a total weight of the catalyst.
9. The method of claim 1, fritter comprising drying the supported-palladium , calcining the supported-palladium composition, or both.
10. The method of claim 1, further comprising adding at least one selectivity enhancer to the supported-palladium composition to form an enhanced supported-palladium composition, wherein the selectivity enhancer comprises a compound selected from the group consisting of Group IB metals, Group IB metal compounds, phosphorus, sulfur, phosphorus-containing compounds, sulfur-containing confounds, alkaline metals, alkaline metal-containing compounds, silver, silver-containing coconuts, iodine, iodide-containing compounds, and combinations thereof
11. The method of claim 10, wherein the enhanced supported-palladium from about 0.001 to about 10 weight percent selectivity enhancer based on a total weight of the catalyst.

12. The method of claim 10, further comprising drying the enhanced supported-palladium composition, calcining the enhanced supported-palladium composition, or both.
13. The method of claim 1, further comprising reducing the supported-palladium composition.

14. A method of selectively hydrogenating a highly unsaturated hydrocarbon to aii unsaturated hydrocarbon comprising: contacting under hydrogenation conditions the highly unsaturated hydrocarbon with a selective hydrogenation catalyst composition produced by the method of claim 1.
15. the method of claim 14, wherein a fouling rate of the selective hydrogenation catalyst is at least about 25 percent less than a fouling rate of an otherwise same catalyst having anon-chlorided catalyst support under like hydrogenation conditions.
16. The method of claim 14, wherein the highly unsaturated hydrocarbon surprises acetylene, methyl acetylene, procaine, or combinations thereof
17. A selective hydrogenation catalyst
(a) a chlorided inorganic catalyst support containing from about 5 to about 2000 ppm by weight of chlorine;
(b) about 0.01 to about 1.0 weight percent palladium based on a total weight of the catalyst; and
(c) about 0.01 to about 10 weight percent silver based on a total weight of the catalyst.
18. The catalyst of claim 17, wherein the chlorided inorganic catalyst support
compass from about 10 to about 1200 ppm by weight of chlorine based on a total
weight of the catalyst, wherein the catalyst conprises from about 0.01 to about 0.8
weight percent palladium based on a total weight of the catalyst, and wherein the
catalyst from about 0.01 to about 5 weight percent silver based on a total
weight of the catalyst.

19. The catalyst of claim 17, further comprising one or more selectivity enhancers
selected from the group consisting of iodine, iodide-containing compounds,
phosphorus, phosphorus-containing compounds, sulfur, sulfite-containing compounds,
alkaline metals, alkaline metal-containing coir pounds, and combinations thereof
20. The catalyst of claim 19, wherein the selective hydrogenation catalyst
comprises from about 0.001 to about 10 weight percent selectivity enhancer based on
a total weight of the catalyst.

Documents:

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Patent Number

269096

Indian Patent Application Number

423/CHENP/2008

PG Journal Number

40/2015

Publication Date

02-Oct-2015

Grant Date

30-Sep-2015

Date of Filing

25-Jan-2008

Name of Patentee

CHEVRON PHILLIPS CHEMICAL COMPANY LP

Applicant Address

10001 SIX PINES DRIVE THE WOODLANDS TEXAS 77380

Inventors:

#	Inventor's Name	Inventor's Address
1	BERGMEISTER, JOSEPH, III	3618 PURPLE MEADOW LANE KINGWOOD, TX 77345
2	HONG, ZONGXUAN	4043 ELM CREST TRAIL HOUSTON, TX 77059
3	CHEUNG, TIN-TACK, PETER	5111 MAPLE HILL TRAIL KINGWOOD, TX 77354

PCT International Classification Number

B01J 23/44

PCT International Application Number

PCT/US06/27298

PCT International Filing date

2006-07-14

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	60/702,745	2005-07-27	U.S.A.