Preparation of poly alpha-1,3-glucan esters using cyclic organic anhydrides

Abstract

Poly alpha-1,3-glucan ester compounds are disclosed herein with a degree of substitution of about 0.001 to about 3.0. Also disclosed are methods of producing poly alpha-1,3-glucan ester compounds using cyclic organic anhydrides.

What is claimed is: 
     
         1 . A composition comprising a poly alpha-1,3-glucan ester compound represented by the structure: 
       
         
           
           
               
               
           
         
       
       wherein
 (i) n is at least 6; 
 (ii) each R is independently an —H or a first group comprising —CO—C x —COON, wherein the —C x — portion of said first group comprises a chain of 2 to 6 carbon atoms; and 
 (iii) the compound has a degree of substitution with the first group of about 0.001 to about 3.0. 
 
     
     
         2 . The composition of  claim 1 , wherein the —C x — portion of said first group comprises only CH 2  groups. 
     
     
         3 . The composition of  claim 2 , wherein said first group comprises:
 —CO—CH 2 —CH 2 —COON,   —CO—CH 2 —CH 2 —CH 2 —COON,   —CO—CH 2 —CH 2 —CH 2 —CH 2 —COON,   —CO—CH 2 —CH 2 —CH 2 —CH 2 —CH 2 —COON, or   —CO—CH 2 —CH 2 —CH 2 —CH 2 —CH 2 —CH 2 —COON.   
     
     
         4 . The composition of  claim 1 , wherein the —C x — portion of said first group comprises:
 (i) at least one double-bond in said carbon atom chain, and/or 
 (ii) at least one branch comprising an organic group. 
 
     
     
         5 . The composition of  claim 4 , wherein the —C x — portion of said first group comprises at least one double-bond in said carbon atom chain. 
     
     
         6 . The composition of  claim 5 , wherein said first group comprises:
 —CO—CH═CH—COOH.   
     
     
         7 . The composition of  claim 4 , wherein the —C x — portion of said first group comprises at least one branch comprising an organic group. 
     
     
         8 . The composition of  claim 7 , wherein said first group comprises: 
       
         
           
           
               
               
           
         
       
     
     
         9 . A method of producing a poly alpha-1,3-glucan ester compound, the method comprising:
 (a) contacting poly alpha-1,3-glucan in a reaction with a cyclic organic anhydride, thereby producing a poly alpha-1,3-glucan ester compound represented by the structure:   
       
         
           
           
               
               
           
         
         
           wherein 
           (i) n is at least 6; 
           (ii) each R is independently an —H or a first group comprising —CO—C x —COON, wherein the —C x — portion of said first group comprises a chain of 2 to 6 carbon atoms; and 
           (iii) the compound has a degree of substitution with the first group of about 0.001 to about 3.0; 
         
       
       and
 (b) optionally, isolating the poly alpha-1,3-glucan ester compound produced in step (a). 
 
     
     
         10 . The method of  claim 9 , wherein the reaction initially consists of the poly alpha-1,3-glucan and cyclic organic anhydride, wherein the cyclic organic anhydride is melted. 
     
     
         11 . The method of  claim 9 , wherein the reaction does not comprise an organic solvent. 
     
     
         12 . The method of  claim 9 , wherein the reaction comprises aqueous conditions. 
     
     
         13 . The method of  claim 12 , wherein a basic pH is maintained during the reaction. 
     
     
         14 . The method of  claim 9 , wherein the poly alpha-1,3-glucan and poly alpha-1,3-glucan ester are each in a solid form during the reaction. 
     
     
         15 . The method of  claim 9 , wherein the reaction does not comprise a catalyst.