Process for making n-butyl esters from butadiene

Abstract

Process for making a butyl ester from butadiene, comprising (a) reacting butadiene with a saturated aliphatic monocarboxylic acid to form a mixture of n-butenyl and secondary butenyl esters, (b) separating the n-butenyl ester from the secondary butenyl ester, and (c) hydrogenating the n-butenyl ester separated in step (b) in the presence of a catalyst to the corresponding n-butyl ester.

1. A process for making a butyl ester from butadiene, said process comprising
 a) reacting butadiene with a saturated aliphatic monocarboxylic acid in a reaction mixture containing water to form a mixture of n-butenyl and secondary butenyl esters, wherein the level of water in the reaction mixture is in the range from 0.05 to 5% w/w based on the carboxylic acid;  
 b) separating the n-butenyl ester from the secondary butenyl ester; and  
 c) hydrogenating the n-butenyl ester separated in step b) in the presence of a catalyst to the corresponding n-butyl ester.  
 
     
     
       2. A process as claimed in  claim 1 , wherein the butadiene employed in step a) is in the form of a hydrocarbon mixture comprising butadiene. 
     
     
       3. A process as claimed in  claim 1 , the secondary butenyl ester separated in step b) is i) recycled step a), ii) hydrogenated in the presence of a catalyst to produce sec-butyl ester, iii) thermally cracked to produce the starting butadiene and a saturated aliphatic monocarboxylic acid, or iv) further reacted. 
     
     
       4. A process as claimed in  claim 1 , wherein the carboxylic acid is acetic acid. 
     
     
       5. A process as claimed in  claim 1 , wherein step a) is carried out in the presence of a heterogeneous or homogeneous acidic catalyst. 
     
     
       6. A process as claimed in  claim 5 , wherein the catalyst is a heterogeneous catalyst in the form of an ion-exchange resin. 
     
     
       7. A process as claimed in  claim 5 , wherein the catalyst is a homogeneous catalyst in the form of triflic acid or a triflate salt. 
     
     
       8. A process for making butenyl esters from butadiene comprising reacting butadiene with a saturated aliphatic monocarboxylic acid in a reaction mixture containing water to form a mixture of n- butenyl and secondary butenyl esters, wherein the level of water in the reaction mixture is in the range from  0 . 05  to  5   %  w/w based on the carboxylic acid.   
     
     
       9. A process of  claim 8  wherein the n- butenyl ester is separated from the secondary butenyl ester.   
     
     
       10. A process as claimed in  claim 8 , wherein the carboxylic acid is acetic acid. 
     
     
       11. A process as claimed in  claim 8 , wherein the reaction is carried out in the presence of a heterogeneous or homogeneous acidic catalyst. 
     
     
       12. A process as claimed in  claim 11 , wherein the catalyst is a heterogeneous catalyst in the form of an ion- exchange resin.   
     
     
       13. A process as claimed in  claim 11 , wherein the catalyst is a homogeneous catalyst in the form of triflic acid or a triflate salt. 
     
     
       14. A process as claimed in  claim 9 , wherein the carboxylic acid is acetic acid. 
     
     
       15. A process as claimed in  claim 9 , wherein the reaction is carried out in the presence of a heterogeneous or homogeneous acidic catalyst. 
     
     
       16. A process as claimed in  claim 15 , wherein the catalyst is a heterogeneous catalyst in the form of an ion- exchange resin.   
     
     
       17. A process as claimed in  claim 15 , wherein the catalyst is a homogeneous catalyst in the form of triflic acid or a triflate salt. 
     
     
       18. A process of  claim 8  wherein the saturated aliphatic monocarboxylic acid contains  1  to  6  carbon atoms. 
     
     
       19. A process of  claim 9  wherein separated secondary butenyl ester is recycled to the butadiene- carboxylic acid reaction mixture.   
     
     
       20. A process of  claim 19  wherein the saturated aliphatic monocarboxylic acid is acetic acid and the reaction of carboxylic acid and butadiene is carried out in the presence of a heterogeneous acidic catalyst. 
     
     
       21. A process of  claim 8  wherein the butadiene employed is in the form of a hydrocarbon mixture comprising butadiene.