Isomerization of olefins with carboxylic acid

Abstract

A method of modifying the activity of a solid acid catalyst by contact with a carboxylic acid is presented. The modified catalyst is exposed to a feed mixture including olefins in a reaction zone, and an effluent including an isomerized olefin product is withdrawn from the reaction zone. The isomerized olefin product includes a more random distribution of internal olefins than the olefins of the feed mixture. The feed mixture and the isomerized olefin product include linear olefins. The isomerization results in no more than about 10 weight percent additional branched, compared to the olefins of the feed mixture, among the olefins of the isomerized olefin product. The isomerized olefin product includes no more than about 20 weight percent dimer. The olefin monomers of the feed mixture and the isomerized olefin product include from about 4 to about 30 carbon atoms. The effluent includes no more than about 20 weight percent ester. The solid acid catalyst may be an acidic ion exchange resin. The feed mixture may include olefins, esters, and carboxylic acid.

What we claim as our invention is:  
     
         1 . A method comprising: 
 modifying the activity of a solid acid catalyst by contact with a carboxylic acid;    exposing the modified catalyst within a reaction zone to a feed mixture including olefins; and    withdrawing from said reaction zone an isomerized olefin product.    
     
     
         2 . The method of  claim 1  wherein the locations of the double bonds among the olefins of said isomerized olefin product are more randomly distributed than among the olefins of said feed mixture.  
     
     
         3 . The method of  claim 1  wherein said isomerized olefin product comprises a substantially thermodynamic distribution of internal olefins.  
     
     
         4 . The method of  claim 3  wherein said substantially thermodynamic distribution of internal olefins comprises no more than about 5 weight percent alpha-olefins.  
     
     
         5 . The method of  claim 3  wherein said substantially thermodynamic distribution of internal olefins comprises no more than about 1 weight percent alpha-olefins.  
     
     
         6 . The method of  claim 1  wherein said feed mixture comprises alpha-olefins.  
     
     
         7 . The method of  claim 3  wherein said substantially thermodynamic distribution of internal olefins comprises a weight percent 2-alkene content within about 4 weight percent of the result of the formula: 200/(C#-3); wherein C# is defined as the number of carbon atoms in an olefin.  
     
     
         8 . The method of  claim 3  wherein said substantially thermodynamic distribution of internal olefins comprises from about 66 to about 71 weight percent 2-alkenes among olefins having 6 carbon atoms; from about 40 to about 44 weight percent 2-alkenes among olefins having 8 carbon atoms; from about 28 to about 33 weight percent 2-alkenes among olefins having 10 carbon atoms; from about 22 to about 26 weight percent 2-alkenes among olefins having 12 carbon atoms; from about 18 to about 22 weight percent 2-alkenes among olefins having 14 carbon atoms; from about 15 to about 19 weight percent 2-alkenes among olefins having 16 carbon atoms; from about 13 to about 17 weight percent 2-alkenes among olefins having 18 carbon atoms; from about 11 to about 16 weight percent 2-alkenes among olefins having 20 carbon atoms; from about 10 to about 15 weight percent 2-alkenes among olefins having 22 carbon atoms; from about 9 to about 14 weight percent 2-alkenes among olefins having 24 carbon atoms; from about 9 to about 13 weight percent 2-alkenes among olefins having 26 carbon atoms; from about 8 to about 12 weight percent 2-alkenes among olefins having 28 carbon atoms; and from about 7 to about 11 weight percent 2-alkenes among olefins having 30 carbon atoms.  
     
     
         9 . The method of  claim 1  wherein said feed mixture and said isomerized olefin product comprise linear olefins.  
     
     
         10 . The method of  claim 9  wherein no more than about 10 weight percent of the olefins of said feed mixture comprise branched olefins.  
     
     
         11 . The method of  claim 10  wherein said method results in less than about 10 weight percent additional branched olefins among the olefins of said isomerized olefin product.  
     
     
         12 . The method of  claim 10  wherein said method results in less than about 5 weight percent additional branched olefins among the olefins of said isomerized olefin product.  
     
     
         13 . The method of  claim 10  wherein said method results in less than about 3 weight percent additional branched olefins among the olefins of said isomerized olefin product.  
     
     
         14 . The method of  claim 1  wherein an effluent from said reaction zone comprises from about 85 to about 95 weight percent olefin monomers, from about 0 to about 10 weight percent olefin dimers, from about 0 to about 15 weight percent esters, and from about 0 to about 5 weight percent carboxylic acid.  
     
     
         15 . The method of  claim 1  wherein said isomerized olefin product comprises no more than about 20 weight percent dimer.  
     
     
         16 . The method of  claim 1  wherein said isomerized olefin product comprises no more than about 10 weight percent dimer.  
     
     
         17 . The method of  claim 1  wherein said isomerized olefin product comprises no more than about 5 weight percent dimer.  
     
     
         18 . The method of  claim 1  wherein said isomerized olefin product comprises no more than about 1 weight percent dimer.  
     
     
         19 . The method of  claim 1  wherein said olefins and said isomerized olefin product comprise one or more olefins having from about 4 to about 30 carbon atoms.  
     
     
         20 . The method of  claim 1  wherein said olefins and said isomerized olefin product comprise one or more olefins having from about 4 to about 20 carbon atoms.  
     
     
         21 . The method of  claim 1  wherein said olefins and said isomerized olefin product comprise one or more olefins having from about 16 to about 18 carbon atoms.  
     
     
         22 . The method of  claim 1  wherein said olefins comprise a sufficient number of carbon atoms such that said olefins exist in the liquid phase under suitable reaction conditions.  
     
     
         23 . The method of  claim 1  wherein said olefins are convertible to olefins capable of existing in the liquid phase under suitable reaction conditions.  
     
     
         24 . The method of  claim 1  wherein said isomerized olefin product comprises no more than about 20 weight percent alpha olefin.  
     
     
         25 . The method of  claim 1  wherein said isomerized olefin product comprises no more than about 10 weight percent alpha olefin.  
     
     
         26 . The method of  claim 1  wherein said isomerized olefin product comprises no more than about 5 weight percent alpha olefin.  
     
     
         27 . The method of  claim 1  wherein said isomerized olefin product comprises no more than about 1 weight percent alpha olefin.  
     
     
         28 . The method of  claim 1  wherein an effluent from said reaction zone comprises no more than about 20 weight percent ester.  
     
     
         29 . The method of  claim 1  wherein an effluent from said reaction zone comprises no more than about 12 weight percent ester.  
     
     
         30 . The method of  claim 1  wherein an effluent from said reaction zone comprises no more than about 8 weight percent ester.  
     
     
         31 . The method of  claim 1  wherein an effluent from said reaction zone comprises no more than about 3 weight percent ester.  
     
     
         32 . The method of  claim 1  wherein said solid acid catalyst comprises an acidic ion exchange resin.  
     
     
         33 . The method of  claim 1  wherein said solid acid catalyst comprises a sulfonated copolymer of styrene and divinylbenzene.  
     
     
         34 . The method of  claim 32  wherein said solid acid catalyst further comprises a macroreticular pore structure.  
     
     
         35 . The method of  claim 1  wherein said feed mixture comprises carboxylic acid.  
     
     
         36 . The method of  claim 1  wherein said feed mixture comprises esters.  
     
     
         37 . The method of  claim 35  wherein said carboxylic acid comprises no more than about 8 weight percent of said feed mixture.  
     
     
         38 . The method of  claim 35  wherein said carboxylic acid comprises no more than about 5 weight percent of said feed mixture.  
     
     
         39 . The method of  claim 35  wherein said carboxylic acid comprises no more than about 3 weight percent of said feed mixture.  
     
     
         40 . The method of  claim 35  wherein said carboxylic acid comprises no more than about 1 weight percent of said feed mixture.  
     
     
         41 . The method of  claim 1  wherein said carboxylic acid is generated by a compound capable of generating a carboxylic acid under the conditions within the reaction zone.  
     
     
         42 . The method of  claim 41  wherein said carboxylic acid is generated from an acid anhydride.  
     
     
         43 . The method of  claim 41  wherein said carboxylic acid is generated from an ester via reverse esterification.  
     
     
         44 . The method of  claim 1  wherein said carboxylic acid is present in an amount sufficient to saturate substantially all of said solid acid catalyst's active sites.  
     
     
         45 . The method of  claim 1  wherein said carboxylic acid is selected from the group consisting of formic acid, acetic acid, propionic acid, butyric acid, pentanoic acid, hexanoic acid, octanoic acid, nonanoic acid, decanoic acid, carboxylic acids heavier than decanoic acid, and combinations thereof.  
     
     
         46 . The method of  claim 1  wherein said carboxylic acid is acetic acid.  
     
     
         47 . The method of  claim 1  wherein said carboxylic acid is propionic acid.  
     
     
         48 . The method of  claim 1  wherein said solid acid catalyst is substantially free of water.  
     
     
         49 . The method of  claim 41  wherein said feed mixture comprises no more than about 1000 parts per million by weight of water.  
     
     
         50 . The method of  claim 41  wherein said feed mixture comprises no more than about 500 parts per million by weight of water.  
     
     
         51 . The method of  claim 41  wherein said feed mixture comprises no more than about 100 parts per million by weight of water.  
     
     
         52 . The method of  claim 1  wherein said carboxylic acid reactivates said solid acid catalyst by displacement of water.  
     
     
         53 . A catalyst system for isomerization of olefins comprising: 
 a solid acid catalyst; and    a carboxylic acid.    
     
     
         54 . The catalyst system of  claim 53  wherein said olefins comprise alpha-olefins.  
     
     
         55 . The system of  claim 53  wherein said solid acid catalyst comprises an acidic ion exchange resin.  
     
     
         56 . The system of  claim 53  wherein said solid acid catalyst comprises a sulfonated copolymer of styrene and divinylbenzene.  
     
     
         57 . The catalyst system of  claim 53  wherein said carboxylic acid is selected from the group consisting of formic acid, acetic acid, propionic acid, butyric acid, pentanoic acid, hexanoic acid, octanoic acid, nonanoic acid, decanoic acid, carboxylic acids heavier than decanoic acid, and combinations thereof.  
     
     
         58 . The catalyst system of  claim 53  wherein said carboxylic acid is acetic acid.  
     
     
         59 . The catalyst system of  claim 53  wherein said carboxylic acid is propionic acid.  
     
     
         60 . An isomerization system comprising: 
 a reaction zone;    a solid acid catalyst;    a carboxylic acid; and    a feed having olefins;    wherein, upon the presence of said solid acid catalyst, said carboxylic acid, and said feed in said reaction zone, the system produces an effluent including an isomerized olefin product having a distribution of internal olefins that is more random than the distribution of internal olefins in said feed.    
     
     
         61 . The system of  claim 60  wherein said feed and said effluent comprise linear olefins.  
     
     
         62 . The system of  claim 60  wherein said feed comprises alpha olefins.  
     
     
         63 . The system of  claim 60  wherein said effluent further comprises isomers of esters.  
     
     
         64 . The system of  claim 60  wherein said effluent further comprises a carboxylic acid.  
     
     
         65 . The system of  claim 60  wherein said effluent further comprises olefin dimers.  
     
     
         66 . The system of  claim 60  further comprising a separation apparatus for receipt of said effluent and separation of the components of said effluent.  
     
     
         67 . The system of  claim 66  further comprising at least one recycle stream from said separation apparatus to said feed mixture.  
     
     
         68 . The system of  claim 67  wherein said recycle steam comprises a carboxylic acid.  
     
     
         69 . The system of  claim 67  wherein said recycle stream comprises isomers of esters.  
     
     
         70 . The system of  claim 60  wherein said feed comprises carboxylic acid.  
     
     
         71 . The system of  claim 60  wherein said feed comprises a compound capable of generating a carboxylic acid under the conditions in said reaction zone.  
     
     
         72 . A method of modifying the activity of a solid acid catalyst for isomerization of olefins comprising contacting the solid acid catalyst with carboxylic acid.  
     
     
         73 . A method of isomerizing olefins that increases the randomness of the distribution of internal olefins comprising: 
 modifying a solid acid catalyst by contact with a carboxylic acid; and    exposing the modified catalyst to olefins within a reaction zone.    
     
     
         74 . A method of concurrently removing water from a solid acid catalyst and saturating substantially all of said catalyst's active sites comprising contacting said catalyst with a carboxylic acid.