Use of a modified acid in dual purpose biomass delignification

Abstract

Method for controlled delignification of lignocellulosic feedstock and conversion of lignin depolymerization products into at least one ester compound, said method comprising the steps of:providing an acidic composition having a pH of less than 1, said acidic composition comprising:an acid selected from the group consisting of:sulfuric acid;an alkylsulfonic acid; andan arylsulfonic acid;a source of peroxide;an alcohol selected from the group consisting of C1-C6 linear alcohol and C3-C6 branched alcohol and mixtures thereof;exposing said lignocellulosic feedstock to said acidic composition for a period of time sufficient for the acidic composition to react with the lignocellulosic feedstock to obtain a liquid phase containing lignin depolymerization products and diester compounds and a solid phase comprising cellulose fibers;optionally, separating the liquid phase from the solid phase recovering a mixture of diesters, lignin monomers and cellulose fibers; andoptionally, separating said lignin depolymerization products from said diester compounds.

1 . A method to perform a controlled delignification of lignocellulosic feedstock and conversion of lignin depolymerization products into at least one ester compound, said method comprising the steps of:
 a) providing an acidic composition having a pH of less than 1, said acidic composition comprising:
 i) an acid selected from sulfuric acid, an alkylsulfonic acid, an arylsulfonic acid, and combinations thereof; 
 ii) a source of peroxide; and 
 iii) an alcohol selected from a C 1 -C 8  linear alcohol, a C 3 -C 8  branched alcohol, and mixtures thereof; 
   b) exposing said lignocellulosic feedstock to said acidic composition for a period of time sufficient for the acidic composition to react with the lignocellulosic feedstock to obtain
 a liquid phase comprising: 
 i) lignin depolymerization products; 
 ii) lignin monomers; and 
 iii) diester compounds; and 
 a solid phase comprising cellulose fibers; 
   c) separating the liquid phase from the solid phase;   d) recovering from said liquid phase a mixture comprising diester compounds, lignin monomers, lignin depolymerization products; and   e) optionally, separating said lignin depolymerization products from said diester compounds and said lignin monomers.   
     
     
         2 . A method for depolymerizing a lignin-containing material into a mixture comprising diesters and lignin monomers, said method comprising the steps of:
 a) providing an acidic composition having a pH of less than 1, said acidic composition comprising:
 i) an acid selected from sulfuric acid, an alkylsulfonic acid, an arylsulfonic acid, and combinations thereof; 
 ii) a source of peroxide; and 
 iii) an alcohol selected from a C 1 -C 8  linear alcohol, a C 3 -C 8  branched alcohol, and mixtures thereof; 
   b) exposing said lignin-containing material to said acidic composition for a period of time sufficient for the acidic composition to yield a mixture comprising lignin depolymerization products, lignin monomers, and diester compounds;   c) optionally, separating said lignin depolymerization products from said diesters and said lignin monomers.   
     
     
         3 . A method for depolymerizing a lignin oligomeric material into a mixture comprising diesters and lignin monomers, where said method comprises the steps of:
 a) providing an acidic composition having a pH of less than 1, said acidic composition comprising:
 i) an acid selected from the group consisting of: sulfuric acid, an alkylsulfonic acid, an arylsulfonic acid, and combinations thereof; and 
 ii) a source of peroxide; 
 iii) an alcohol selected from a C 1 -C 8  linear alcohol, a C 3 -C 8  branched alcohol, and mixtures thereof; 
   b) exposing said lignin oligomeric material to said acidic composition for a period of time sufficient for the acidic composition to yield a mixture comprising: lignin depolymerization products, lignin monomers, and diester compounds;   c) optionally, separating said lignin depolymerization products from said diesters and said lignin monomers.   
     
     
         4 . The method according to  claim 1 , wherein the alcohol is selected from methanol, ethanol, n-propanol, isopropanol, n-butanol, and isobutanol. 
     
     
         5 . The method according to  claim 1 , wherein the alcohol and the sulfuric acid are present in a molar ratio ranging from 1.8:1 (alcohol:sulfuric acid) to 10:1 (alcohol:sulfuric acid). 
     
     
         6 . The method according to  claim 1 , wherein the alcohol and the sulfuric acid are present in a molar ratio ranging from 3:1 (alcohol:sulfuric acid) to 5:1 (alcohol:sulfuric acid). 
     
     
         7 . The method according to  claim 1 , wherein the peroxide and the sulfuric acid are present in a molar ratio ranging from 3:1 (peroxide:sulfuric acid) to 1:10 (peroxide:sulfuric acid). 
     
     
         8 . The method according to  claim 1 , wherein the peroxide and the sulfuric acid are present in a molar ratio ranging from 1:3 (peroxide:sulfuric acid) to 1:7 (peroxide:sulfuric acid). 
     
     
         9 . The method according to  claim 1 , wherein the peroxide and the sulfuric acid are present in a molar ratio of approximately 1:5 (peroxide:sulfuric acid). 
     
     
         10 . The method according to  claim 1 , wherein the peroxide and the alcohol are present in a molar ratio ranging from 1:2.3 (peroxide:alcohol) to 1:20 (peroxide:alcohol). 
     
     
         11 . The method according to  claims 1 , wherein the peroxide and the alcohol are present in a molar ratio ranging from 1:5 (peroxide:alcohol) to 1:15 (peroxide:alcohol). 
     
     
         12 . The method according to  claim 1 , wherein the peroxide and the alcohol are present in a molar ratio ranging from 1:7 (peroxide:alcohol) to 1:10 (peroxide:alcohol). 
     
     
         13 . A one-pot process to delignify and convert lignin into diesters using a lignocellulosic feedstock, said process comprising the steps of:
 a) providing a vessel;   b) providing said lignocellulosic feedstock;   c) providing an acidic composition having a pH of less than 1, said acidic composition comprising:
 i) an acid selected from sulfuric acid, an alkylsulfonic acid, and an arylsulfonic acid; 
 ii) a source of peroxide; 
 iii) an alcohol selected from a C 1 -C 6  linear alcohol, a C 3 -C 6  branched alcohol, and mixtures thereof; 
   d) exposing said lignocellulosic feedstock to said composition in said vessel for a period of time sufficient to depolymerize at least 80% of the lignin present in said lignocellulosic feedstock and esterify at least a portion of said depolymerized lignin into at least one diester, and yielding a liquid phase comprising lignin depolymerization products, lignin monomers, diester compounds, and a solid phase comprising cellulose fibers;   e) separating the liquid phase from the solid phase;   f) recovering from said liquid phase a mixture comprising diesters, lignin monomers, and lignin depolymerization products; and   g) optionally, separating said lignin depolymerization products from said diesters and said lignin monomers.   
     
     
         14 . The process according to  claim 13 , wherein the alkylsulfonic acid is selected from methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, and combinations thereof. 
     
     
         15 . The process according to  claim 13 , wherein the arylsulfonic acid is selected from toluenesulfonic acid, benzenesulfonic acid, and combinations thereof.