Antioxidant blends for fatty acid methyl esters (biodiesel)

Abstract

This invention provides stabilized biodiesels comprising (1) biodiesel, such as fatty acid methyl ester (FAME), (2) mono- or bis-hindered phenolic derived from 2,6-di-tert-butylphenol, and (3) N,N′-di-substituted para-phenylene diamine. Also methods of stabilizing biodiesel are provided involving adding (2) and (3) to (1).

1 . A composition derived from biodiesel, mono- or bis-hindered phenolic derived from 2,6-di-tert-butylphenol, and N,N′-di-substituted para-phenylene diamine, wherein the combined amount of the mono- or bis-hindered phenolic and the N,N′-di-substituted para-phenylene diamine is from about 50 ppm to about 5000 ppm based on the biodiesel. 
     
     
         2 . The composition of  claim 1  wherein
 (a) the biodiesel consists essentially of crude biodiesel;   (b) the mono- or bis-hindered phenolic derived from 2,6-di-tert-butylphenol comprises:
 (i) ortho-tert-butylphenol, 
 (ii) 2,6-di-tert-butylphenol, 
 (iii) 2,4,6-tri-tert-butylphenol, 
 (iv) 4,4′-methylenebis(2,6-di-tert-butylphenol), 
 (v) 3,5-di-tert-butyl-4-hydroxyphenylhydrocinnamicacid, methyl ester, 
 (vi) 3,5-di-tert-butyl-4-hydroxyphenylhydrocinnamicacid, C7-C9 branched alkyl esters, 
 (vii) 2,6-di-tert-butyl-alpha-dimethylamino-p-cresol, or 
 (viii) butylated hydroxytoluene; and 
   (c) the N,N′-di-substituted para-phenylene diamine comprises:
 (i) N,N′-di-sec-butyl-p-phenylenediamine, 
 (ii) N,N′-diisopropyl-p-phenylenediamine, or 
 (iii) N,N′-bis-(1,4-dimethylpentyl)-p-phenylenediamine. 
   
     
     
         3 . The composition of  claim 2  wherein the crude biodiesel is derived from soybean oil, canola oil, palm oil, coconut oil, rapeseed oil, corn oil, or used vegetable oil. 
     
     
         4 . The composition of  claim 2  wherein the crude biodiesel is a fatty acid methyl ester. 
     
     
         5 . The composition of  claim 1  wherein
 (a) the biodiesel consists essentially of distilled biodiesel;   (b) the mono- or bis-hindered phenolic derived from 2,6-di-tert-butylphenol comprises:
 (i) ortho-tert-butylphenol, 
 (ii) 2,6-di-tert-butylphenol, 
 (iii) 2,4,6-tri-tert-butylphenol, 
 (iv) 4,4′-methylenebis(2,6-di-tert-butylphenol), 
 (v) 3,5-di-tert-butyl-4-hydroxyphenylhydrocinnamicacid, methyl ester, 
 (vi) 3,5-di-tert-butyl-4-hydroxyphenylhydrocinnamicacid, C7-C9 branched alkyl esters, 
 (vii) 2,6-di-tert-butyl-alpha-dimethylamino-p-cresol, or 
 (viii) butylated hydroxytoluene; and 
   (c) the N,N′-di-substituted para-phenylene diamine comprises:
 (i) N,N′-di-sec-butyl-p-phenylenediamine, 
 (ii) N,N′-diisopropyl-p-phenylenediamine, or 
 (iii) N,N′-bis-(1,4-dimethylpentyl)-p-phenylenediamine. 
   
     
     
         6 . The composition of  claim 5  wherein the distilled biodiesel is derived from soybean oil, canola oil, palm oil, coconut oil, rapeseed oil, corn oil, or used vegetable oil. 
     
     
         7 . The composition of  claim 1  wherein the combined amount of the mono- or bis-hindered phenolic and the N,N′-di-substituted para-phenylene diamine is from about 100 ppm to 2500 ppm based on the biodiesel. 
     
     
         8 . The composition according to  claim 1  wherein the weight ratio of the 2,4,6-tri-tert-butylphenol to the N,N′-di-substituted para-phenylene diamine is: a) greater than about 1; b) greater than about 1.25; or c) greater than about 1.5. 
     
     
         9 . A composition derived from biodiesel, 2,4,6-tri-tert-butylphenol, and N,N′-di-substituted para-phenylene diamine, wherein the weight ratio of the 2,4,6-tri-tert-butylphenol to the N,N′-di-substituted para-phenylene diamine is a) greater than about 1. 
     
     
         10 . The composition according to  claim 9  wherein the ratio of the 2,4,6-tri-tert-butylphenol to the N,N′-di-substituted para-phenylene diamine is from about 10:1 to about 1:10 by on weight. 
     
     
         11 . A composition prepared by combining biodiesel, mono- or bis-hindered phenolic derived from 2,6-di-tert-butylphenol, and N,N′-di-substituted para-phenylene diamine, wherein the combined amount of the mono- or bis-hindered phenolic and the N,N′-di-substituted para-phenylene diamine is from about 50 ppm to about 5000 ppm based on the biodiesel. 
     
     
         12 . The composition of  claim 11  wherein
 (a) the biodiesel consists essentially of crude biodiesel;   (b) the mono- or bis-hindered phenolic derived from 2,6-di-tert-butylphenol comprises:
 (i) ortho-tert-butylphenol, 
 (ii) 2,6-di-tert-butylphenol, 
 (iii) 2,4,6-tri-tert-butylphenol, 
 (iv) 4,4′-methylenebis(2,6-di-tert-butylphenol), 
 (v) 3,5-di-tert-butyl-4-hydroxyphenylhydrocinnamicacid, methyl ester, 
 (vi) 3,5-di-tert-butyl-4-hydroxyphenylhydrocinnamicacid, C7-C9 branched alkyl esters, 
 (vii) 2,6-di-tert-butyl-alpha-dimethylamino-p-cresol, or 
 (viii) butylated hydroxytoluene; and 
   (c) the N,N′-di-substituted para-phenylene diamine comprises:
 (i) N,N′-di-sec-butyl-p-phenylenediamine, 
 (ii) N,N′-diisopropyl-p-phenylenediamine, or 
 (iii) N,N′-bis-(1,4-dimethylpentyl)-p-phenylenediamine. 
   
     
     
         13 . The composition of  claim 11  wherein
 (a) the biodiesel consists essentially of distilled biodiesel;   (b) the mono- or bis-hindered phenolic derived from 2,6-di-tert-butylphenol comprises:
 (i) ortho-tert-butylphenol, 
 (ii) 2,6-di-tert-butylphenol, 
 (iii) 2,4,6-tri-tert-butylphenol, 
 (iv) 4,4′-methylenebis(2,6-di-tert-butylphenol), 
 (v) 3,5-di-tert-butyl-4-hydroxyphenylhydrocinnamicacid, methyl ester, 
 (vi) 3,5-di-tert-butyl-4-hydroxyphenylhydrocinnamicacid, C7-C9 branched alkyl esters, 
 (vii) 2,6-di-tert-butyl-alpha-dimethylamino-p-cresol, or 
 (viii) butylated hydroxytoluene; and 
   (c) the N,N′-di-substituted para-phenylene diamine comprises:
 (i) N,N′-di-sec-butyl-p-phenylenediamine, 
 (ii) N,N′-diisopropyl-p-phenylenediamine, or 
 (iii) N,N′-bis-(1,4-dimethylpentyl)-p-phenylenediamine. 
   
     
     
         14 . A composition comprising biodiesel, 2,4,6-tri-tert-butylphenol, and N,N′-di-substituted para-phenylene diamine, wherein the weight ratio of the 2,4,6-tri-tert-butylphenol to the N,N′-di-substituted para-phenylene diamine is a) greater than about 1. 
     
     
         15 . The composition according to  claim 14  wherein the ratio of the 2,4,6-tri-tert-butylphenol to the N,N′-di-substituted para-phenylene diamine is from about 10:1 to about 1:10 by on weight. 
     
     
         16 . A method of improving oxidation stability of a composition comprising biodiesel by combining the composition and mono- or bis-hindered phenolic derived from 2,6-di-tert-butylphenol, and N,N′-di-substituted para-phenylene diamine such that the combined amount of the mono- or bis-hindered phenolic and the N,N′-di-substituted para-phenylene diamine is from about 50 ppm to 5000 ppm based on the biodiesel. 
     
     
         17 . The method of  claim 16  wherein
 (a) the biodiesel consists essentially of crude biodiesel;   (b) the mono- or bis-hindered phenolic derived from 2,6-di-tert-butylphenol comprises:
 (i) ortho-tert-butylphenol, 
 (ii) 2,6-di-tert-butylphenol, 
 (iii) 2,4,6-tri-tert-butylphenol, 
 (iv) 4,4′-methylenebis(2,6-di-tert-butylphenol), 
 (v) 3,5-di-tert-butyl-4-hydroxyphenylhydrocinnamicacid, methyl ester, 
 (vi) 3,5-di-tert-butyl-4-hydroxyphenylhydrocinnamicacid, C7-C9 branched alkyl esters, 
 (vii) 2,6-di-tert-butyl-alpha-dimethylamino-p-cresol, or 
 (viii) butylated hydroxytoluene; and 
   (c) the N,N′-di-substituted para-phenylene diamine comprises:
 (i) N,N′-di-sec-butyl-p-phenylenediamine, 
 (ii) N,N′-diisopropyl-p-phenylenediamine, or 
 (iii) N,N′-bis-(1,4-dimethylpentyl)-p-phenylenediamine. 
   
     
     
         18 . The method of  claim 17  wherein the crude biodiesel is derived from soybean oil, canola oil, palm oil, coconut oil, rapeseed oil, corn oil, or used vegetable oil. 
     
     
         19 . The method of  claim 17  wherein the crude biodiesel is a fatty acid methyl ester. 
     
     
         20 . The method of  claim 16  wherein
 (a) the biodiesel consists essentially of distilled biodiesel;   (b) the mono- or bis-hindered phenolic derived from 2,6-di-tert-butylphenol comprises:
 (i) ortho-tert-butylphenol, 
 (ii) 2,6-di-tert-butylphenol, 
 (iii) 2,4,6-tri-tert-butylphenol, 
 (iv) 4,4′-methylenebis(2,6-di-tert-butylphenol), 
 (v) 3,5-di-tert-butyl-4-hydroxyphenylhydrocinnamicacid, methyl ester, 
 (vi) 3,5-di-tert-butyl-4-hydroxyphenylhydrocinnamicacid, C7-C9 branched alkyl esters, 
 (vii) 2,6-di-tert-butyl-alpha-dimethylamino-p-cresol, or 
 (viii) butylated hydroxytoluene; and 
   (c) the N,N′-di-substituted para-phenylene diamine comprises:
 (i) N,N′-di-sec-butyl-p-phenylenediamine, 
 (ii) N,N′-diisopropyl-p-phenylenediamine, or 
 (iii) N,N′-bis-(1,4-dimethylpentyl)-p-phenylenediamine. 
   
     
     
         21 . The method of claim  120  wherein the distilled biodiesel is derived from soybean oil, canola oil, palm oil, coconut oil, rapeseed oil, corn oil, or used vegetable oil. 
     
     
         22 . The method of  claim 16  wherein the combined amount of the mono- or bis-hindered phenolic and the N,N′-di-substituted para-phenylene diamine is from about 100 ppm to 2500 ppm based on the biodiesel. 
     
     
         23 . The method according to  claim 16  wherein the weight ratio of the 2,4,6-tri-tert-butylphenol to the N,N′-di-substituted para-phenylene diamine is a) greater than about 1. 
     
     
         24 . The method according to  claim 16  wherein the ratio of the 2,4,6-tri-tert-butylphenol to the N,N′-di-substituted para-phenylene diamine is from about 10:1 to about 1:10 by on weight.