3-hydroxycarboxylic acid production and use in branched polymers

Abstract

This invention relates to a process for the preparation of a 3-hydroxycarboxylic acid from a 3-hydroxynitrile. More specifically, 3-hydroxyvaleronitrile is converted to 3-hydroxyvaleric acid in high yield at up to 100% conversion, using as an enzyme catalyst 1) nitrile hydratase activity and amidase activity or 2) nitrilase activity of a microbial cell. 3-Hydroxyvaleric acid is used as a substitute for ε-caprolactone in the preparation of highly branched copolyester.

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       12 . A process for synthesizing a highly branched copolyester product comprising the steps of: 
 (a) contacting and heating a mixture of 
 1) at least one hyperbranching hydroxycarboxylic acid or its ester of the structure (R 2 O) n —R—[C(O)O R 1 ] m , wherein R is C 1-12  hydrocarbyl radical with n+m free valencies, R 1  is H, C 1-12  or hydroxyl substituted C 1-12  hydrocarbyl radical, R 3 , R 4 , R 5 , R 6 , R 7  is H or C 1-12  hydrocarbyl radical, R 2  is H or (O)C R 3 , n+m is 3 or more, and provided that one of n and m is 1,  
 2) a linear 3-hydroxycarboxylic acid or its ester of the structure R 20 —C R 4 , R 5 C R 6 , R 7 C(O)O R 1 , and  
 3) an esterification catalyst; and  
   (b) collecting the highly branched copolyester product of step (a).    
   
   
       13 . The process of  claim 12  wherein the hyperbranching hydroxycarboxylic acid is dimethylolpropionic acid and/or trimethylolacetic acid, the linear 3-hydroxycarboxylic acid is 3-hydroxyvaleric acid, and the esterification catalyst is tin dicarboxylate or a protonic acid.  
   
   
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