Title of Invention

A PROCESS FOR THE PREPARATION OF OLEFIN SULFONATES

Abstract

The invention is particularly related to the production of such sulfonates from unsaturated hydrocarbons by reacting them with bisulfite in the presence of a free radical initiator and solvent reaction media. More particularly this invention relates to the preparation of alkane sulfonates using the addition of bisulfite ions to olefins present in the distillates from thermal cracking operations such as coker or visbreaking. The invention provides a simplified process which can be carried out at temperatures in the range suitable for atmospheric pressure operation utilizing a minimum amount of initiating catalyst and agitation to maintain a disperse system of the two-phases during the course of the reaction, which generally runs from 2 to 20 hours. Good yields of alpha olefin sulfonates are obtained. The main achievement of this process is the utilization of alpha olefins from cracked hydrocarbons i.e. alpha olefin-paraffin mixture, which is available in large quantities in refineries at a very cheaper rate and so far has not been utilized

Full Text

The present invefion relates to a process for the preparation of olefin sulfonates. The invention is particularly related to the production of such sulfonates from unsaturated hydrocarbons by reacting them with bisulfite in the presence of a free radical initiator and solvent reaction media. More particularly this invention relates to the preparation of alkane sulfonates using the addition of bisulfite ions to olefins present in the distillates from thermal cracking operations such as coker or visbreaking. The alkane sulfonates are effective as detergents. These detergents provide outstanding detergency, high compatibility with water, and good wetting and foaming properties. Alpha olefin sulfonates are free of skin irritants and sensitizers, and a great importance is their high degree of biodegradability. They are used in high quality shampoos, light-duty detergents, bubble baths and heavy-duty liquid and powder detergents. The product obtained by the present invention can be utilized by detergent industry specially used in personal care products. The addition of sodium bisulfite to unsaturated organic compounds has long been known. One of the early patents in which this reaction was used is Patent No. US 2,028,091, which described the addition of sodium bisulfite to esters of maleic acid. The reaction is carried out by heating an aqueous alcoholic solution of sodium bisulfite and the maleic acid ester in a closed vessel. Several patents e.g. U.S. pat. Nos. 4,171,291; 3,356,717; 3,168,535; 3,349,122; 4,070,396 describe the above mentioned reaction with olefin(s) in presence of peroxide initiators to form alkane sulfonates. It has long been further, known that the above mentioned reaction is feasible with alpha olefins, olefins with pendant or internal unsaturation. The pendant or internal olefins react at slower rate than alpha olefin and the rate of reaction is decreased with increase in the molecular weight of olefin. Such observations are reported in open literature (Chemical Reviews, 37, pp-351; Industrial and Engineering Chemistry, Product Research and Development, No.1, March 1964, pp-3). Lot of work has been done to develop a process for the production of organic sulfonates by reaction of hydrocarbons with inorganic bisulfites. Need of such process is especially felt because oHM* high marketability of the product and the relatively low cost of the individual raw materials. Much of the work on the preparation of olefin sulfonates has been done in United States and in Britain, which is covered by numerous patents e.g. 2, 653, 970; 3,084,186 and 3,168,555 and British Patent No. 995, 376. However, to our knowledge, no process for production of organic sulfonates by reaction of the unsaturated hydrocarbons with inorganic bisulfites has been found sufficiently economic to be practiced on a commercial scale. All of the above cited patents need a emphasis precise control of the pH. Various ranges of pH have been found to be beneficial to the reaction forming organic sulfonates. The process disclosed in U.S. patent no. 2,653,970 requires about from 16 to 40 hours for obtaining reasonable yields of sodium a Iky I sulfonate. German patent No. 1,098,936, French Patent No. 1,222,105 and U.S. patent no. 3,084,186 claim the use of peroxide compounds as promoters to reduce the reaction time. Patent No. 3, 479, 397 discloses the use of nitrates as promoters. U. S. Patent. No. 3,541,140 describes the preparation of alkane sulfonates wherein the process is accomplished by pre-reacting the olefin with an oxygen containing gas and then reacting a non-interfering bisulfite with the pre-reacted olefin. The use of nitrates as promoters give rise to alkyl sulfonates containing nitrogen in an amount of about 1 g per alkyl chain and on a prior oxygenation of olefins gives rise to recycle products, which are no longer reactive with respect to bisulfite. French Patent No. 1,453,398 and U.S. Patent No. 3,450,749 claims the use of gamma or UV radiations, which do not give good yields and show some technological difficulties. Similarly, U. S. Patent No. 3,558,693 discloses the separation of alkane sulfonate product from the reaction mixture by maintaining a critical alcohol to water ratio and a critical temperature range. The U.S. Patent No. 2,504,411 discloses the necessity of maintaining certain molar ratios of bisulfite ions to olefins and of olefins to organic peroxide initiators and the importance of controlling the reaction temperature in rather narrow limits and pairing up the initiators with a specific solvent to obtain good yields of alpha olefin sulfonates. The U.S. Patent No. 3,084,186 describes the addition of bisulfites to olefins in a system to maintain fixed concentration of bisulfiite. This also requires regular analysis of the bisulfite ion during the course of reaction, which makes this process difficult and impractical. The important drawbacks associated with hitherto known processes can be summarized as: (i) Economically viable production of organic sulfonates has not been achieved so far. (ii) Reaction time is generally very high ranging from 16-40 hrs (U.S. Patent No. 2,653,970). (iii) Reasonably high yield of product is not obtained. (iv) The high cost and non-availability of raw materials are other interfering factors for the large-scale production. (v) Sometimes very controlled reaction parameters (e.g. addition of bisulfite) make the process more tedious. (vi) Some of the process utilized nitrates as the initiators. The product thus obtained is associated with nitrogen, which makes the recycle of unreacted product more difficult. (vii) For rapid completion of the reaction controlled and gradual introduction of the bisulfite compound, which is usually a salt like ammonium or sodium bisulfite is necessary. It being stated that without such controlled introduction, long reaction times are required, extending upto 100 hours. These efforts, in turn, involved a careful supervision over the bisulfite concentration. Also, in order to check the rate of addition, aliquot portions of the reaction mixture were periodically withdrawn and tested as a pre requisite to the maintenance of the bisulfite concentration within desired limits. Such periodic tests were done as often as every 10 minutes. From the prior processes it may be seen that they are marked by tedious techniques, which result in increasing the cost of the product and prolong the reaction well beyond desired times. According to the present invention, it is proposed to eliminate completely the need for such careful control, including both the gradual addition of bisulfite and the periodic testing of the reaction mixture. All the reactants, are used in substantially near stoichiometric amounts, and are mixed in a single addition, there being no gradual or stepwise addition of reactants. The main object Cjpie present invention is to provide a process for preparation of olefin sulfonates which obviates the drawbacks as detailed above. Another object of the present invention is to provide a process for prepare olefin sulfonates by the addition of bisulfite ions to an alkene having at least 10 carbon atoms per molecule to form an alpha olefin sulfonates. Still another object of the present invention is to use cracked distillates from thermal cracking processes containing alpha olefins without purification as a cheap and easily available source of olefins, e.g. mixed streams such as alpha olefins, paraffin mixtures obtained from kerosene/gas oil distillate fraction from thermal coking/visbreaking operations in a refinery which goes as a low value fuel component. Typically such mixed alpha olefins contain about 25-30% olefins, 70-75% paraffins and about 0.1- 0.5% aromatics. For reasons of economics, we prefer to use sodium bisulfite in our process, but other water-soluble bisulfites, for example ammonium bisulfite or aliphatic amines or pyridine bisulfite may be used. Sodium bisulfite, while in general less reactive and more difficult to remove from the reaction products, is advantageous in the manner that the sodium alkane sulfonates formed are generally more effective as detergents. Further in the process, according to the present invention the manner in which feed and bisulfite are mixed is not critical or complicated. It is pointed out, however, that employing peroxides for the free radical initiation will result in rapid preferential reaction with the bisulfite. The importance of the free radical initiator is to selectively oxidize bisulfite to sulfite radicalion without formation of sulfate ion. Accordingly the present invention provides a process for the preparation of olefin sulfonates which comprises reacting an alkali metal bisulfite with a hydrocarbon feed selected from one or more alpha olefins and a mixture of olefins and paraffins having 10 to 18 carbon atoms in a molar ratio of feed to bisulfite in the range of 1:1 to 1:5 in a aqueous or non aqueous saturated monohybrid alcohol having one to four carbon atoms in the presence of peroxide having proxy group -O-O- attached to carbon bonded carbon atom of at least one organic radical, as a free radical forming catalyst in the range of 0.01 to 2.0 weight % of the olefin to obtain two phases disperse system at a temperature of 20-25°C, agitating the above said reaction mixture and slowly raising its temperature^lffb reflux temperature over a period of 1 to 2 hours and further maintaining the said elevated temperature for a period of 2 to 16 hours till the reaction mixture turns clear and water white to obtained the desired product. In an embodiment of the present invention the mixture of olefins and parffins used is obtained from the thermally cracked hydrocarbon distillate In another embodiment of the present invention the bisulfite used is of the general formula MHSOa wherein M is an alkali metal or alkaline earth metal or an ammonium ion. In yet another embodiment of the present invention bisulfite used is selected from the group consisting of sodium bisulfite, ammonium bisulfite and sodium meta bisulfite. In still another embodiment of the present invention the ratio of olefins to paraffins used is in the mixture of olefins and paraffins is in the range of 1:9 to 1:1. In still another embodiment of the present invention the thermally cracked distillate used is consisting of olefins, saturated hydrocarbons and aromatics. In still another embodiment of the present invention the catalyst used preferably is benzoyl peroxide. In still another embodiment of the present invention the catalyst used preferably in the range of 0.1-5% of olefin. In still another embodiment of the present invention the temperature used preferably in the range of 70°C to 150°C. In still another embodiment of the present invention the reaction is carried out preferably fora period 8-12 hrs. In still another embodiment of the present invention said monohydrate alcohol is selected from the group consisting of methanol, ethanol, isopropanol and tertiary butanol. While the reaction can be carried out at normal temperatures, it is accelerated at increased temperatures. The temperatures preferred are those approaching the boiling point of the olefin solvent employed, which in the case of the above mentioned alcohols is in the range of about 70-82°C. A reflux condenser can be associated with the reaction vessel if it is anticipated that the temperature will possibly exceed the boiling point the solvent. After the reaction is complete, the reaction mixture can be subjected to separate saturated hydrocarbons followed by an evaporation step wherein water and organic solvent are separated from the product alpha olefin sulfonate. AOS yields of 40-90 percent are obtained by the inventive process. The "yield" as the term is here in employed is the weight percent of olefin feed charged to the reaction zone converted to the alpha olefin sulfonate. The reaction is carried out by agitating an aqueous solution of the bisulfite with an alcoholic solution of the olefin at a temperature in the range from 25-100°C preferably somewhat less than the boiling point of the solvent and for a time sufficient to complete the bisulfite addition in the presence of free radical-forming initiating catalyst. The temperature, order of addition of the reactants and their ratio are not critical and as little as 0.01% of the catalyst based on the weight of olefin can be used. The amount of catalyst to be used is 0.5 to 5%, preferably less than 2% wt based on olefin. The alcoholic solution of feed was treated with aqueous solution of bisulfite wherein the bisulfite is of the general formula MHSO3 in which M is an alkali metal, alkaline earth metal or an ammonium preferably sodium bisulfite or ammonium bisulfite or sodium meta bisulfite. The mole ratio of bisulfite used varies from 0.5 - 5 mol % on the basis of olefin present in the feed. All the reactants can be introduced into the reactor gradually or at one time and by maintaining a concentration of the alcohol having Ci - C4 carbon atom and water varying from in the range 0-100% such that an excess of alcohol is not used or an insufficient amount of water is used for dissolving the bisulfite, a two-layer or two- phase rather than a three-phase system is provided. By agitating the two-phase system in which the catalyst acts at the interface, a turbid appearing dispersion of the phases is maintained and shortly before the reaction is completed, two clear phase results, and separate these layers The upper layer contain paraffin, unreacted olefins and others. The products of the instant invention encompass this clear solution, or a solid material resulting from the^paporation or distillation of the alcohol from the clear solution or a solid material resulting from the removal of both the alcohol and the water. In order to more fully illustrate the process of this invention and manner of practicising the same, the following examples are presented. The examples are provided for illustrative purposes and not to limit the invention as defined by the claims. The examples also demonstrate that the alpha olefins mixture containing Cio-Cia carbon atoms can also be used to prepare alpha olefin sulfonates using the present invention. The examples further demonstrate that the process of the present invention can also be used to prepare alpha olefin sulfonates by reaction alpha olefins-paraffin mixture obtained from thermally cracked petroleum streams obtained from coker operations and having Cio-Cia carbon atoms. In such a case only alpha olefins present in the cracked stream reacts to form sulfonates. The following examples are given by way of illustration and therefore should not be construed to limit the scope of the present invention. Example-1 Into a 500 ml three-necked flask equipped with a reflux condenser, a Teflon - bladed glass agitator and a thermometer, 31.2 g of sodium bisulfite, previously dissolved in 85 ml of water, was charged. There was then added 34.3g of 1-tetradecene in 170 ml isopropyl alcohol and 0.4 g of benzoyl peroxide. The agitation was started and the temperature was gradually raised fro 25°C to 78°C over a period of 2 hrs. Heating and agitation continued for 2 hrs. On evaporation of the alcohol and a water- white, soap-like, water-soluble powder resulted. The conversion, basis consumed olefin, is found to be 80%. Example-2 The same procedure and ratio of ingredients were carried out as in Example-1 except that reaction was carried out for 10 hrs with high stirring. The product obtained was similar to that obtained in Example-1. The conversion, basis consumed olefin, is found to be 90+%. Example-3 Using the same apparatus as in Example -1; the charge to the flask was 34.3 g of olefin - paraffin mixture (30%: 70%, d4 product), 75 ml of isopropyl alcohol, 0.2 g benzoyl peroxide and 14 g sodium bisulfite, previously dissolved in 38 ml of water. The temperature was gradually raised from 25°C to 78°C with high stirring over a period of 2 hrs. Heating was continued for a period of 10 hrs. Two separate layers were obtained. The alcohol was distilled from the reaction mixture and these two layers were separated by separating funnel. The lower layer is a clear water white liquid. On evaporation of the water a water-white, soap like, water- soluble powder resulted. The conversion, basis consumed olefin, is found to be 40%. Example-4 The procedure of Example-1 was carried out with about 2.5 moles of bisulfite and 12 hrs. The product obtained was similar to that obtained in Example-3. The conversion, basis consumed olefin, is found to be 80%. Example-5 Using the same apparatus as in Example-1, the charge to the flask was 70 g of Ci4-C16 mixture from cracked hydrocarbons, 105 ml of isopropyl alcohol, 0.6 g of benzoyl peroxide and 26 g of sodium bisulfite, previously dissolved in 52 ml of water (olefin: bisulfite ratio is 1: 2.5 mol). The product obtained was similar to that obtained in Example - 3. The conversion, basis consumed olefin, is found to be 35%. Example-6 Using the same apparatus as in Example-3, the charge to the flask was 68 g of Ci4-Ci5 mixture from cracked hydrocarbons, 101 ml of isopropyl alcohol, 0.59 g of benzoyl peroxide and 26 g of sodium bisulfite, previously dissolved in 52 ml of water (olefin: bisulfite ratio is 1:2.5 mol). The product obtained was similar to that obtained in Example - 3. The conversion, basis consumed olefin, is found to be 58%. Example-7 The procedure of Example-3 was carried out using 1-dodecene and dodecane mixture (30%: 70%) with 1.7 moles of bisulfite for 12 hrs. The product obtained was similar to that obtained in Example - 3. The conversion, basis consumed olefin, is found to be 50%. Example-8 The procedure of Example-3 was carried out using 1-dodecene and dodecane mixture (30%:70%) with 2.5 moles of bisulfite for 12 hrs. The product obtained was similar to that obtained in Example - 3. The conversion, basis consumed olefin, is found to be 87%. Example-9 The procedure of Example-3 was carried out using 1-decene and decane mixture (30%: 70%) with 1.7 moles of bisulfite for 12 hrs. The product obtained was similar to that obtained in Example-3. The conversion, basis consumed olefin, is found to be 78%. Example-10 The procedure of Example-3 was carried out using 1-decene and decane mixture (30%:70%) with 2.5 moles of bisulfite for 12 hrs. The product obtained was similar to that obtained in Example -3. The conversion, basis consumed olefin, is found to be 95%. Olefins can be made to react with bisulfite in the presence of other hydrocarbons. No prior separation of olefins from a mixture of saturated and unsaturated hydrocarbons is necessary. In the process of the invention an olefin having a carbon chain length of from 10 to 18, preferably an alpha-olefin, is reacted with bisulfite ions in a liquid medium, in the presence of a substance known to initiate said reaction, comprising the steps of: (i) Forming a mixture of olefin and a co-solvent consisting of water and a short chain alcohol containing from 1 to 4 carbon atoms wherein the alcohol present is about 10 58% to ao'Ht 70% by weight of the co-solvent and the alcohol is present in an amount of from about 50% to about 100% by weight of the olefin, (ii) Adding an aqueous solution of bisulfite ions, containing 1-3 mols of bisulfite ion per mol of olefin and the alcohol is present in an amount from about 16% to about 19% by weight in the final reaction mixture, and (iii) Maintaining the reaction zone, is preferably at a temperature of from 70°C to 100°C. The preferred alcohol is isopropyl alcohol and the amount of initiator is preferably not more than 0.1% to 2% relative to the olefin. Although this invention has been primarily described in conjunction with examples and by reference to embodiments thereof, it is evident that many alternatives, modifications, and variants will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intented to embrace within the invention all such alternatives, modifications, and variations that fall within the spirit and scope of the appended claims. The main advantages of the present invention are: 1. It has been found that the present process can be carried out efficiently and high yields can be obtained by charging all of the ingredients into the reaction vessel at the same time without undue regard for solvent selection, solvent concentration, time or temperature. Contrary to U. S. Patent No. 3, 084, 186 in which the rate of addition of the bisuphite to the olefin is strictly controlled and to U.S. Pat. No. 2,504,411 in which may factors are controlled, among them the temperature within narrow limits and the ratios of initiators solvents, and olefins. 2. The present invention provides a process wherein the terminal olefins can be made to react almost quantitatively with bisulfite under the experimental conditions to produce alpha olefin sulfonates by using water-soluble bisulfites and olefins (obtained from coker distillates) containing from 10 to 18 carbon atoms. 3. Thus, the invention provides a simplified process which can be carried out at temperatures in the range suitable for atmospheric pressure operation utilizing a minimum amount of initiating catalyst and agitation to maintain a disperse system of the two-pKases during the course of the reaction, which generally runs from 2 to 20 hours. Good yields of alpha olefin sulfonates are obtained. 4. The main achievement of this process is the utilization of alpha olefins from cracked hydrocarbons i.e. alpha olefin-paraffin mixture, which is available in large quantities in refineries at a very cheaper rate and so far has not been utilized. 5. The other usefulness of this process lies in the conversion of alpha olefins present in the alpha olefin-paraffin mixture into high marketability product i.e. alpha olefin sulfonates, a potential detergent type. No prior separation of alpha olefins from coker distillate is required. We claim: 1. A process for the preparation of olefin sulfonates which comprises reacting an alkali metal bisulfite with a hydrocarbon feed selected from one or more alpha olefins and a mixture of olefins and paraffins having 10 to 18 carbon atoms in a molar ratio of feed to bisulfite in the range of 1:1 to 1:5 in a aqueous or non aqueous saturated monohybrid alcohol having one to four carbon atoms in the presence of peroxide having proxy group -O-O- attached to carbon bonded carbon atom of at least one organic radical, as a free radical forming catalyst in the range of 0.01 to 2.0 weight % of the olefin to obtain two phases disperse system at a temperature of 20-25°C, agitating the above said reaction mixture and slowly raising its temperature to reflux temperature over a period of 1 to 2 hours and further maintaining the said elevated temperature for a period of 2 to 16 hours till the reaction mixture turns clear and water white to obtained the desired product. 2. A process as claimed in claim 1 wherein the mixture of olefins and parffins used is obtained from the thermally cracked hydrocarbon distillate 3. A process as claimed in claim 1-2 , wherein the bisulfite used is of the general formula MHSOs wherein M is an alkali metal or alkaline earth metal or an ammonium ion. 4. A process as claimed in claim 1-3 wherein bisulfite used is selected from the group consisting of sodium bisulfite, ammonium bisulfite and sodium meta bisulfite. 5. A process as claimed in claims 1 to 4, wherein the ratio of olefins to paraffins used in the mixture of olefins and paraffins is in the range of 1:9 to 1:1. 6. A process as claimed in claims 1 to 5, wherein the thermally cracked distillate used is consisting of olefins, saturated hydrocarbons and aromatics. 7. A process as claimed in claims 1 to 6 wherein the catalyst used preferably is benzoyl peroxide. 8. A process as ciaimed in claims 1 to 7, wherein the catalyst used is preferably in the range of 0.1-5% of olefin. 9. A process as claimed in claims 1 to 8, wherein the temperature used is preferably in the range of 70°C to 150°C. 10. A process as claimed in claims 1 to 9, wherein the reaction is carried out preferably for a period 8-12 hrs. 11.A process as claimed in claims 1 to 10, wherein said monohydrate alcohol is selected from the group consisting of methanol, ethanol, isopropanol and tertiary butanol. 12. A process for the preparation of olefin sulfonates substantially as herein described with reference to the examples accompanying this specification.

Documents:

389-DEL-2002-Abstract-(19-02-2009).pdf

389-del-2002-abstract.pdf

389-del-2002-claims.pdf

389-DEL-2002-Correspondence-Others-(19-02-2009).pdf

389-del-2002-correspondence-others.pdf

389-del-2002-correspondence-po.pdf

389-del-2002-description (complete).pdf

389-del-2002-form-1.pdf

389-del-2002-form-18.pdf

389-del-2002-form-2.pdf

389-DEL-2002-Form-3-(19-02-2009).pdf

389-del-2002-form-3.pdf