Title of Invention

"A METHOD OF PRODUCING BISPHENOL-A"

Abstract

A method of producing bisphenol-A by the reaction of phenol and acetone with the production of bisphenol-A and water in countercurrent and multistage contact with a solid acid catalyst of the kind such as hereinbefore described in the presence of stripping medium boiling in the range of 50 to 90°C at the condition of pressure of the condensation and which is inert under the reaction conditions, whereby the stripping medium removes water from the reaction and acetone and acetone is dissolved in the phenol.

Full Text

PROCESS FOR THE PRODUCTION OF BISPHENOL-A BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to the production of bisphenol-A byttie of phenol with acetone. More particularly the invention relatesto;a process the reaction products, especially water, are separated concurrently with the;reafi;iti.Qjn in a distillation column reactor. More particularly the invention relates toe.,pr,Qcess wherein the water of reaction is removed by stripping with an inert hydr0earbo;n-ya.p0r produced in the reboiler of a distillation column reactor. Related Information Bisphenol-A is a basic feedstock or intermediate product for.the commercial manufacture of various polymers including the polyaryJates, polyannides, polyetherimides, polysulfuones and polycarbonates^etc., epoxy resinsand-modifse! phenol-formaldehyde resins, etc. Various processes for producing.bisphenol-Aifrjsjn the reaction of phenol with acetone in the presence of an acidic ion-exchange *§sin catalyst have been disclosed in U.S. patents 4,308,404; 4,391,997; 4,404555; 4,471,154 and 5,087,767. The method of carrying out catalytic reactions, wherein the componentaQflhe reaction system are concurrently separable by distillation, are described.v U.S. Patents 4,215,011;4,232,177; 4,242,530; 4,250,052; 4,302,356; a commonly assigned herewith. Briefly, structures which serve as both catalyst site and distillation structure are then disposed in the distillation cplum:n,,reaetor;MvA variety of catalyst structures for this use are disclosed in jcomrnonlyasS patents 4,443,559; 4,536,373; 5,057,468; 5,130,102; 5,133$42y = 5,262,012; 5,266,546; 5,348,710; 5,431,890; and 5,730,843,which,areincorp0mtfd herein. These structures have been particularly well adaptedifor use with acielJGcioiexchange resins. The method is commonly known as catalytic distillation andihas been successfully adapted in various forms for many reactions, including etherification of olefins with alcohols (U.S. patent 4,302,254;), selective hydrogenation (U.S. patent 6,169,21861), hydrodesulfurization. (LbS.. 5,779,883), isomerization (U.S. patent 6,495,732) and aromatic alkylation (U.S. patent (U.S. patent 4,849,569). A catalytic distillation column reaction is a benefit first, because the reaction is occurring concurrently with distillation, the initial reaction..products and.loiher stream components are removed from the reaction zone as quickly as possible reducing the likelihood of side reactions. Second, because all the components^are boiling the temperature of reaction is controlled by the boiling point of the mixtuine^at the system pressure. The heat of reaction simply creates more boil up^but>no increase in temperature at a given pressure. As a result, a great deal of contrGclover the rate of reaction and distribution of products can be achieved by regulati'ngiithe system pressure. U.S. patent 5,679,312 discloses producing bisphenol-A by carrying out the reaction by feeding phenol and acetone concurrently downflow in a distillation column reactor having acidic ion exchange resin catalysts held on trays by screens. An inert stripping gas, e.g., nitrogen or argon, is fed in the bottom of the distilJatipn column reactor to aid in removing the water of reaction. With its concurrentfesol'Of the phenol and acetone the patentee gets only about 96% conversion ofethe acetone. The patentee exhibited a lack of skill and knowledge in regard to .catalytic distillation and its areas of significant commercial use as well as being unable to envision how a catalytic distillation system could be used to carry out the reaction of acetone with phenol to produce bisphenol-A. ; - It is an adva ntage of the present invention that the catalytic distillation.system, with its inherent benefits is employed for the production of bisphenolTA from the condensation reaction of phenol and acetone. It is a further advantage th-at-an inert hydrocarbon serves to remove water of reaction from the reaction system and is easily reused by return to the reaction system. It is a further advantage? that substantially all of the acetone is trapped in the reaction zone and near;100% conversion is obtained. SUMMARY OF THE INVENTION Bisphenol-A is efficiently produced from the condensation of phenoband acetone via countercurrent and multistage contact with a solid acid catalyst in'the presence of stripping medium which is inert under the reaction conditions and boiling in the range of 50 to 90 °C at the pressure in the column, preferably inert hydrocarbons, which includes aliphatic hydrocarbons such as normal,he^a,ng,..; A. preferred contacting system is a distillation column.reactor where the,-catalyst is contained within a distillation mass transfer structure. A preferred water"re.nnffiyal agent is a C6 hydrocarbon, e.g., normal hexane. In the present invention the stripping medium is one that is inert and which has both a liquid and vapor state in the reactor, i.e., boiling, such that thevMapjDrs strip the water from the reaction mixture and are condensed along with the water and separated therefrom. Preferably the stripping medium is not soluble feany substantial degree with water, so the separation can be made by decanting. The preferred mode of operation is that characterized by a distillation condition ^existing within the reaction zone. The present invention is carried ouUn a catalyst- packed column which can be appreciated to contain a vapor phase and,s©maJi.guicl.,p|isse. as in any distillation. The distillation column reactor is operated lata,pressure such that the reaction mixture (or components thereof) is boiling in the.eolumn and/or in the bed of the catalyst (distillation conditions). As in any.distillation.there is a temperature profile along the column. At some point along the-Golumn: oc;©^glyst bed a component of the reaction mixture may be a liquid and a vapor at a higher temperature point in the column, thus creating an internaLreflux; whefe^Sgsejris of: the vaporized material in the column, e.g. water and the stripping medium is removed as a vapor. A preferred embodiment of the invention may be described as a proeessifor the reaction of phenol with acetone to produce bisphenol-A comprising: (a) feeding a stoichiometric excess of phenol to a catalyst .zone.wllicri preferably comprises a bed of solid acidic catalyst, such as ion-exchange resin, in a. distillation column reactor and (b) feeding acetone toward the bottom of said catalyst zone; (c) providing a hydrocarbon, which is inert under the .reaction c.ond|tipRs;and boiling in the range of 50 to 90 °C at the pressure in the distillation sojumn reactor, in a state of distillation comprising both a vapor and liquid thereof distillation column reactor; (d) concurrently in said distillation column reactor (i) contacting said acetone and phenol in the presence of .said«aeidic catalyst under conditions of temperature and pressure to form a reaction ^mixture containing unreacted acetone, unreacted phenol, bisphenol-A, and water, whereby said acetone is dissolved in said phenol such that substantially .all of said-acefone is converted to bisphenol-A; V- (ii) stripping said water from said reaction mixture utilizing said hydrocarbon vapor; (e) removing said bisphenol-A and unreacted phenol from the dtstiation . column reactor as bottoms; . (f) removing said water and hydrocarbon vapor from the distillation column reactor as overheads; and (g) condensing said overheads and separating the condensed«?inrert hydrocarbon from the condensed water. In a preferred process the additional steps are: (h) recycling the condensed hydrocarbon to said distillation column reactor (i) flashing said bottoms to separate said unreacted phenol frorm/said bisphenol-A; and (j) condensing the separated phenol and recycling the condensed separated phenol to near the top of said distillation column reactor. BRIEF DESCRIPTION OFTHE DRAWING The FIGURE is a flow diagram of a preferred reactor system employe$4r*the .instant invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Bisphenol-A is formed via the reaction of two moles of phenol with on&4ftQ\e acetone: 2(C6H5OH) + (CH3)2(CO) « [(C6H4OH)]2C(CH3)2 + H2O . The equilibrium constant for this reaction is small (K=0,8 mole fraction basis). The reaction is generally catalyzed by acidic ion exchange resins and is conventionally carried out in the presence of a large stoichiometric excess of phenol which enhances the conversion of acetone and minimizes the production-sQfobyproducts. However, at practical phenol/acetone charge ratios single stage conversion of phenol is small, For example, at a charge composition of 2Q/1j*loJar. phenol/acetone, phenol conversion is only 12% while acetone conversion is:::92$>. Previously the bisphenol-A was recovered from the reaction mjxtu,re?via crystallization of a bisphenol-A/phenol adduct. Feed to the crystallize/ -usua -lly contains on the order of 20 wt.% bisphenol-A, This concentration is obtalra^d :iby allowing the bisphenol-A to build up in the reaction mixture by using reaction stage with intermediate removal of water via vacuum of inert between the stages. In so doing the unreacted phenol and acetone and distribute between the overhead product streams-andihe bottoms stream,coteita inihg the BPA product. In conventional processing the phenol, acetone and water«are subsequently separated in downstream distillation columns. The present invention, simplifies the overall processing scheme by combining reaction and separation steps. This is accomplished by performing -the. reaction in a multistage distillation column reactor configured with structured pa:ckJRg;COo|a.iri|ng the catalyst and which operates with an inert stripping medium fed to the r the column that preferentially removes the water of reaction from the reaction zcine. The water is removed in the distillate stream from the column .. The countercurrentfeed of the present invention provides anothjgridvrjtage in that by feeding liquid phenol to the column above the reaction zpne,, .aee^prje is removed from the ascending vapor stream and returns to the reaction! zone. Thesnet effect is to "trap" the acetone within the reaction zone where it reacts essentia;%to completionThe stripping medium (preferably inert hydrocarbons;) has the -additional function of controlling the reboiler temperature and the temperature profile; in^he lower portion of the reaction zone which is preferably in the 70-80 ° grange/line . inert hydrocarbon has the additional advantage of being readily separablelrpfisthe water in the distillate stream via decantation. The inert hydrocarbon Iayerlra.rrj4he decanter is preferably returned to the column. Thus a constant feed of tdifiiiert stripping medium is not necessary and makeup can be added as required. CATALYSTS ..-...., The reaction of phenol and acetone to produce bisphevnol-A is :catalyzed.rby acidic catalysts, preferably cation exchange resins. Suitable acid cation exchange resins include those which contain sulfonic acid groups, and which may be obtained by polymerization or copolymerization of aromatic vinyl compounds followed-toy sulfonation. Examples of aromatic vinyl compounds suitable for preparing polymers or copolymers are: styrene, vinyl toluene, vinyl naphthalene, vinyl ethylfoenzene, methyl styrene, vinyl chlorobenzene and vinyl xylene. A large variety of methods may be used for preparing these polymers; for example, polymerization al=onre,-or: in admixture with other monovinyl compounds, or by crosslinking with pQlyyfayl compounds; for example, with divinyl benzene, divinyl toluene, divinyl phenylether and others. The polymers may be prepared in the presence or absence of solvents or dispersing agents, and various polymerization initiators:may be used,. :e.g., inorganic or organic peroxides, persulfates, etc. The sulfonic acid group may be introduced into these vinyl aromatic polymers by various known methods; for example, by sulfating the polymers with concentrated sulfuric and chlorosulfonic acid, or by copolymerizing aromatic compounds^which contain sulfonic acid groups (see e.g., US Pat. No. 2,366/007). Further sulfonic acid groups may be introduced into the polymers which already contain suifonic'acid groups; for example, by treatment with fuming sulfuric acid, i,e., sulfuric acid which contains sulfur trioxide. The treatment with fuming sulfuric acid is preferab ly carried ; out at 0 to 150° C and the sulfuric acid should contain sufficient sulfur trioxide so that ft still contains 10 to 50% free sulfur trioxide after the reaction. The resulting products preferably contain an average of 1.3 to 1,8 sulfonic acid groupsp.er aromatic nucleus. Particularly, suitable polymers which contain sulfonic aoidgfofips are copolymers of aromatic monovinyl compounds with aromatic polyviny! compounds, particularly, divinyl compounds, in which the polyvinyl benzen e content is preferably 1 to 20% by weight of the copolymer (see, for example, German-Patent Specification 908,240). The ion exchange resin is generally used in a granular size of about 0.25 to 1 mm, although particles from 0.15 mm up to about2 mrn may. be employed. The finer catalysts provide high surface area, but also result-inHIgh pressure drops through the reactor. The macroretieularform of these catalysts frave much larger surface area exposed and limited swelling which all of these resins undergo in a non-aqueous hydrocarbon medium compared to the gelular catalysts. The container employed to hold the catalyst particles may have any'conlgwration, such as the pockets disclosed in the patents above or the container may be:a single cylinder, sphere, doughnut, cube, tube or the like. Each container containing a solid catalytic material comprises a catalyst component. Each catalyst component is intimately associated with a -spacing component which is comprised of at least 70 volume % open space,up,to:abQut::95 volume % open space. This component may be rigid or resilient ora combination thereof. The combination of catalyst component and spacing component formse catalytic distillation structure. The total volume of open space for the catalytic distillation structure should be at least 10 volume % and preferably at least JO volume % up to about 65 volume %, Thus, desirably the spacing CQmppnent.pr material should comprise about 30 volume % of the catalytic distillation strgctuje, preferably about 30 volume % to 70 volume %. Resilient materials:arepre,ferre,d. One suitable such material is open mesh knitted stainless wire, known generally as demisterwire or an expanded aluminum. Other resilient components may besimilar open mesh knitted polymeric filaments of nylon, teflon and the like. Qthermaterijls such as highly open structures foamed material, e.g., reticulated polyurethanefoarn (rigid or resilient) may be formed in place or applied around the catalyst cpmpprjegt. In the case of larger catalyst components such as from about 1/4 inch to Y pellets, spheres, pills and the like, each such larger component may be individually, intimately associated with or surrounded by the spacing component as describfd above. It is not essential that the spacing component entirely cover the catalyst component. It is only necessary that the spacing component intimately associated with the catalyst component serve to space the various catalyst components away from one another as described above. Thus, the spacing component provides in effect a matrix of substantially open space in which the catalyst components are randomly but substantially evenly distributed. A preferred distillation structure is described in U.S. patent 5,730,843 noted above, which comprises at least two wire mesh tubes arrayed in a substantially parallel, adjacent and vertically aligned row and at least one offset wire mesh tube disposed adjacent to and spaced from said vertically aligned wire mesh tubes. In a more preferred embodiment the distance between the vertically aligned tubes of the columns is sufficient to allow the offset wire mesh tube to overlap the vertically aligned wire mesh tubes without contacting said vertically aligned wire rnesh tub:es to thereby form a tortuous fluid pathway. Referring now to the FIGURE a flow diagram of a preferred reactor system is shown. The distillation column reactor 10 is seen to contain beds of catalyst 12 and 14 which comprise a reaction zone having 50 equilibrium stages with 4 trays above the reaction zone and 4 trays below the reaction zone. Stage 1 is the condenseriO and stage 60 is the reboiler 40. Phenol is fed via flow line 101 .above stage 3 and acetone is fed via flow line 102 above stage 40. The acetone and phenol react in the reaction zone to produce a reaction mixture containing phenol, acetone, bisphenol-A and water. N-hexane recycle is fed via flow line 103 , combined withnhexane recycle 114 to the reboiler 40 through flow lines 116, 117, and 110 eventually to the bottom of the distillation column reactor 10 at about stage 59. The n-hexane strips the water of reaction out as it is formed and removes it as overheads via flow line 104. The overheads are condensed in condenser 20 and collected in receiver/decanter 30 where the water is separated and removed via flow line 1'06, N-hexane (containing a small amount of acetone) is taken from the receiver/decanter 30 via flow line 107 and returned to the distillation column reactor 10 at about stage 56. The water contains about 2% acetone which corresponds to about 99.5% conversion. The bottoms product containing phenol, bisphenol-A and only trade amounts of water and acetone is removed from the distillation column reactor 10 via flow line 111 from reboiler 40. The bottoms product removed via flow line 111 is flashed to 3 psi in flash drum 50 producing a n-hexane rich vapor stream in flow line 112 and a phenol/bisphenol-A liquid stream in flow line 113. The n-hexane rich vapor stream in flow line 112 is cooled (not shown) and passed to knock out chamber 60 where any liquid is removed via flow line 115 before compressing (not shown) and recycling . via flow line 114. A recycle stream from the recovery section (not shown) is also fed to chamber 60 via line 116. Liquid from the knock out chamber 60 in flow line 115 contains essentially phenol and is recycled to distillation column reactor above stage 3. The phenol/bisphenol-A liquid stream in flow line 113 is combined and sent to the bisphenol-A recovery system where the bisphenol-A is reeovered.by crystallization. In the operation of this process the normal hexane or other stripping-ifvedjuiisis recovered and recycled. The only feed of this component to -thecolumn is atstartiapi and for makeup of that lost during the recovery. The recovery of the bisphenol-A is summarily described as follows: The phenol/bisphenol-A stream is combined with other phenol rich recycle . streams from the crystallization systems and is sent to an evaporator system operating at ~2 psi. The resulting vapor is partially condensed producing a hexanerich recycle and phenol rich liquid recycle. The liquid product from the evaporator containing 29 wt.% bisphenol-A is fed to a crystallization system which generates a slurry of bisphenol-A/phenol adduct in phenol. The slurry is centrifugally separated into a mother liquor stream which is cycled to the evaporation system and a solid adduct stream which is wet with phenol for further processing to recover phenol for recycle. The solid adduct stream is combined with net feed liquid phenol stream and heated to resolution temperature. The resulting solution stream is sent to a second crystallization system producing a slurry stream which is separated into further purified adduct stream and mother liquor stream. The latter is cycled to the evaporator feed tank. The phenol wet solid is melted and fed to a second vacuum evaporation system to dephenolate the adduct and product bisphenol-A melt product stream which contains a small amount of phenol. The phenol vapor stream is condensed and sent to the phenol recycle tank. The combined phenol recycle stream is fed to the catalytic distillation column via stream 101. Final purification of the bisphenol-A is via hexane stripping to remove residual phenol and steam stripping to remove residual hexane. The recovered hexane streams are recycled to the CD column. The purified bisphenol-A melt is pelletized or flaked and finally bagged. EXAMPLE The following example demonstrates use of the invention for reacting ;plieiiol with acetone to produce bisphenol-A. Equipment and stream names are -as-given in the figure. Compositions and stream flows, and conditions are in the Table. Main reaction in reactor 10 is the following reaction catalyzed .by a supported acidic cation exchange resin supported in a ma&s exchange .distillation structure: 2 Phenol + Acetone • Bisphenol-A + Water(Table Removed) WE CLAIM: 1 A method of producing bisphenol-A by the reaction of phenol and acetone with the production of bisphenol-A and water in countercurrent and multistage contact with a solid acid catalyst of the kind such as hereinbefore described in the presence of stripping medium boiling in the range of 50 to 90°C at the condition of pressure of the condensation and which is inert under the reaction conditions, whereby the stripping medium removes water from the reaction and acetone and acetone is dissolved in the phenol. 2. The method as claimed in claim 1 wherein said stripping medium comprises inert hydrocarbons. 3. The method as claimed in claim 1 wherein said stripping medium comprises aliphatic hydrocarbons. 4. The method as claimed in claim 1 wherein said stripping medium comprises normal hexane. 5. The method as claimed in claim 1 wherein said catalyst is contained within a distillation mass transfer structure. 6. The method for the production of bisphenol-A as claimed in claim 1, wherein the countercurrent and multistage contact is performed in a distillation column reactor, and wherein; (a) the phenol is fed to near the top of a distillation column reactor and acetone to near the bottom of said distillation column reactor, said distillation column reactor containing a bed of acidic ion-exchange resin of the kind such as hereinbefore described; (b) the stripping medium is fed to the bottom of said distillation column reactor; (c) concurrently in said distillation column rector (i) said acetone and phenol are contacted in the presence of said acidic ion-exchange resin to form a reaction mixture containing unreacted acetone, unreacted phenol, bisphenol-A, and water, and (ii) said acetone is trapped within said distillation column reactor by said phenol whereby substantially all of said acetone is converted to bisphenol-A; (iii) said water is stripped from said reaction mixture utilizing said inert stripping stream; (d) said unreacted phenol and bisphenol-A are removed from said distillation column reactor as bottoms; and (e) said water and inert stripping stream are removed from distillation column reactor as overhead. 7. The method as claimed in claim 6 wherein said inert stripping stream is present as a liquid which boils at the reaction temperature of phenol and acetone. 8. The method as claimed in claim 6 wherein said bottoms is flashed to separate said unreacted phenol as a vapor from said bisphenol-A and said separated phenol is condensed and recycled to near the top of said distillation colunm reactor. 9. The method as claimed in claim 8 wherein any unreacted acetone contained within said bottoms is separated from said bisphenol-A as a vapor along with said unreacted phenol and said condensed phenol is flashed again to remove the unreacted acetone as a vapor, said unreacted acetone being recycled to said distillation column reactor. 10. The method for the reaction of phenol with acetone to produce bisphenol-A as claimed in claim 1, wherein the countercurrent and multistage contact is performed in a distillation column reactor, and wherein: (a) a stoichiometric excess of the phenol is fed to a catalyst zone which comprises a bed of solid acidic catalyst, in the[[a]] distillation column reactor and (b) acetone is fed toward the bottom of said catalyst zone; (c) the stripping medium is fed to in the distillation column reactor; (d) concurrently in said distillation column reactor: (i) said acetone and phenol are contacted in the presence of said acidic catalyst under conditions of temperature and pressure to form a reaction mixture containing unreacted acetone; unreacted phenol, bisphenol-A, and water, whereby said acetone is dissolved in said phenol whereby substantially all of said acetone is converted to bisphenol-A; (ii) said water is stripped from said reaction mixture utilizing said hydrocarbon vapor; (e) said bisphenol-A and unreacted phenol are removed from the distillation column reactor as bottoms; and (f) said water and hydrocarbon vapor are removed from the distillation column reactor as overheads. 11. The method as claimed in claim 10, wherein: (g) said overheads are condensed and the condensed inert hydrocarbon are separated from the condensed water; (h) the condensed hydrocarbon is recycled to said distillation column reactor; (i) said bottoms are flashed to separate said unreacted phenol from said bisphenol-A; and (j) the separated phenol is condensed and recycled to near the top of said distillation column reactor. 12. The method for the production of bisphenol-A as claimed in claim 1, wherein the countercurrent and multistage contact is performed in a distillation column reactor, and wherein: (a) acetone and phenol are fed to the[[a]] distillation column reactor, which contains a bed of acidic ion-exchange resin and includes a reboiler; (b) the stripping medium is a C6 hydrocarbon, which is fed to said reboiler to vaporize a portion of said C6 stream; (c) concurrently in said distillation column reactor (i) said acetone and phenol are contacted in the presence of said acidic ion-exchange resin to form a reaction mixture containing unreacted acetone, unreacted phenol, bisphenol-A, and water, and (ii) said water is stripped from said reaction mixture utilizing said vaporized C6 hydrocarbon; (d) said unreacted phenol and bisphenol-A are removed from said distillation column reactor as bottoms; and (e) said water and vaporized C6 hydrocarbon are removed from said distillation column reactor as overheads. 13. The method as claimed in claim 12 wherein said phenol is fed above said bed of acidic ion-exchange resin and said acetone is fed below said bed of acidic ion-exchange resin such that said acetone is trapped within said distillation column reactor and substantially all of said acetone is converted to bisphenol-A. 14. The method as claimed in claim 12 wherein said overheads are condensed and said C6 hydrocarbon is separated from said water and the separated C6 hydrocarbon is recycled to near the bottom of said distillation column reactor. 15. The method as claimed in claim 12 wherein said bottoms is flashed to separate said unreacted phenol as a vapor from said bisphenol-A and said separated phenol is condensed and recycled to near the top of said distillation column reactor. 16. The method as claimed in claim 15 where any unreacted acetone contained within said bottoms is separated from said bisphenol-A as a vapor along with said unreacted phenol and said condensed phenol is flashed again to remove the unreacted acetone as a vapor, said unreacted acetone being recycled to said distillation column reactor. 17. The method for the production of bisphenol-A as claimed in claim 1, wherein the countercurrent and multistage contact is performed in a distillation column reactor and wherein: (a) phenol is fed to near the top of a distillation column reactor and acetone to near the bottom of said distillation column reactor, said distillation column reactor containing a bed of acidic ion-exchange resin and comprising a reboiler; (b) the stripping medium is a C6 hydrocarbon, which is fed to said reboiler to vaporize a portion of said C6 stream; (c) concurrently in said distillation column reactor (i) said acetone and phenol are contacted in the presence of said acidic ion exchange resin to form a reaction mixture containing unreacted acetone, unreacted phenol, bisphenol-A, and water, and (ii) said acetone is trapped within said distillation column reactor by said phenol such that substantially all of said acetone is converted to bisphenol- A; (iii) said water is stripped said reaction mixture utilizing said vaporized C6 hydrocarbon; (d) said unreacted phenol and bisphenol-A are removed from said distillation column reactor as bottoms; (e) said water and vaporized C6 hydrocarbon are removed from said distillation column reactor as overheads; (f) said overheads are condensed and the condensed C6 hydrocarbon are separated from the condensed water; (g) the condensed C6 hydrocarbon is recycled to near the bottom of said distillation column reactor; (h) said bottoms are flashed to separate said unreacted phenol from said bisphenol-A; and (i) the separated phenol is condensed and recycled to near the top of said distillation column reactor.

Documents:

1348-DELNP-2007-Abstract-(10-06-2011).pdf

1348-delnp-2007-abstract.pdf

1348-DELNP-2007-Assignment-(03-03-2011).pdf

1348-DELNP-2007-Claims-(10-06-2011).pdf

1348-delnp-2007-claims.pdf

1348-DELNP-2007-Correspondence Others-(10-06-2011).pdf

1348-DELNP-2007-Correspondence-Others-(03-03-2011).pdf

1348-delnp-2007-correspondence-others-1.pdf

1348-DELNP-2007-Correspondence-Others.pdf

1348-delnp-2007-description (complete).pdf

1348-DELNP-2007-Drawings-(10-06-2011).pdf

1348-delnp-2007-drawings.pdf

1348-DELNP-2007-Form-1-(10-06-2011).pdf

1348-delnp-2007-form-1.pdf

1348-delnp-2007-form-18.pdf

1348-DELNP-2007-Form-2-(10-06-2011).pdf

1348-delnp-2007-form-2.pdf

1348-DELNP-2007-Form-3-(10-06-2011).pdf

1348-delnp-2007-form-3.pdf

1348-delnp-2007-form-5.pdf

1348-DELNP-2007-GPA-(10-06-2011).pdf

1348-delnp-2007-gpa.pdf

1348-delnp-2007-pct-210.pdf

1348-delnp-2007-pct-220.pdf

1348-delnp-2007-pct-237.pdf

1348-delnp-2007-pct-301.pdf

1348-delnp-2007-pct-notification.pdf

1348-DELNP-2007-Petition 137-(03-03-2011).pdf

1348-DELNP-2007-Petition-137-(10-06-2011).pdf