Process for producing mixed esters of fatty acids as biofuels

Abstract

A process for producing mixed esters of fatty acids as biofuel or additive to a petroleum fuel for use in a compression ignition (CI) engine. The process preferably provides a partial transesterification of a mixture of fatty acid methyl esters with at least one alkyl alcohol containing 2 to 8 carbon atoms in the presence of a heterogeneous solid acid catalyst to produce a mixture of the fatty acid methyl esters and alkyl alcohol esters of the fatty acids.

1 - 24 . (canceled) 
     
     
         25 . A composition useful in a compression ignition (CI) engine, the composition comprising:
 a mixture comprising (a) fatty acid methyl esters and (b) fatty acid alkyl esters of at least one alkyl alcohol containing 2 to 8 carbon atoms,   wherein:
 (i) the mixture has a cloud point that is lower in temperature than that of a mixture comprising the fatty acid methyl esters alone, and 
 (ii) the composition has a cloud point ranging from −4° C. to −12° C. 
   
     
     
         26 . The composition of  claim 25  wherein the fatty acid methyl esters and the fatty acid alkyl esters comprise esters of palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid from soybean oil. 
     
     
         27 . The composition of  claim 25  further comprising an ester of a fermentation or non-fermentation derived organic acid with at least one alkyl alcohol containing 1 to 6 carbon atoms. 
     
     
         28 . The composition of  claim 27  wherein the ester comprises dimethyl succinate. 
     
     
         29 . The composition of  claim 27  wherein the ester is derived from an acid selected from the group consisting of lactic acid, succinic acid, and mixtures thereof. 
     
     
         30 . The composition of  claim 27  wherein the ester is derived from an acid selected from the group consisting of propionic acid, butyric acid, isobutyric acid, and mixtures thereof. 
     
     
         31 . The composition of  claim 27  further comprising an ether selected from the group consisting of dibutyl ether (DBE); methyl tert-butyl ether (MTBE); tertiary amyl methyl ether (TAME); tertiary hexyl methyl ether (THEME); ethyl tertiary butyl ether (ETBE); tertiary amyl ethyl ether (TAEE); propyl ether (DIPE); dipropyl ether; dihexyl ether; dioctyl ether, and iso-amyl-ether. 
     
     
         32 . The composition of  claim 27  further comprising an ether containing at least 6 carbon atoms. 
     
     
         33 . The composition of  claim 25  wherein the fatty acid alkyl esters of at least one alkyl alcohol containing 2 to 8 carbon atoms comprise fatty acid ethyl esters. 
     
     
         34 . The composition of  claim 25  wherein the fatty acid alkyl esters of at least one alkyl alcohol containing 2 to 8 carbon atoms comprise fatty acid butyl esters. 
     
     
         35 . The composition of  claim 25  wherein the fatty acid alkyl esters of at least one alkyl alcohol containing 2 to 8 carbon atoms comprise fatty acid ethyl esters and fatty acid butyl esters. 
     
     
         36 . The composition of  claim 25  wherein the mixture has a cloud point that is 5° C. to 10° C. lower than that of a mixture comprising the fatty acid methyl esters alone. 
     
     
         37 . The composition of  claim 25  wherein the mixture has a cloud point that is 5° C. to 14° C. lower than that of a mixture comprising the fatty acid methyl esters alone. 
     
     
         38 . The composition of  claim 25  wherein a volume ratio between the fatty acid methyl esters and the fatty acid alkyl esters of at least one alkyl alcohol containing 2 to 8 carbon atoms ranges from 6:94 to 34:66 in the composition. 
     
     
         39 . The composition of  claim 25  wherein the fatty acid methyl esters are present in an amount ranging from 3% to 34% of the composition. 
     
     
         40 . The composition of  claim 25  wherein the fatty acid methyl esters are present in an amount ranging from 3% to 6% of the composition. 
     
     
         41 . The composition of  claim 25  wherein the fatty acid alkyl esters of at least one alkyl alcohol containing 2 to 8 carbon atoms are present in an amount ranging from 47% to 94% of the composition. 
     
     
         42 . The composition of  claim 25  further comprising a petroleum diesel fuel present in an amount ranging from 50% to 95% of the composition. 
     
     
         43 . The composition of  claim 25  further comprising glycerol. 
     
     
         44 . A composition useful in a compression ignition (CI) engine, the composition comprising:
 a mixture comprising (a) fatty acid methyl esters and (b) fatty acid alkyl esters of at least one alkyl alcohol containing 2 to 8 carbon atoms,   wherein the mixture has a cloud point that is 5° C. to 14° C. lower than that of a mixture comprising the fatty acid methyl esters alone.