Oxidation-stabilized biodiesel

Abstract

The present invention relates to oxidation-stabilized biodiesel and methods for the production thereof.

1 . A method for the production of oxidation-stabilized biodiesel, the method comprising mixing biodiesel with 0.005 to 0.5% by weight of a composition comprising:
 A) 40-60% by weight of a mixture of at least one C 1 -C 4 -alkylated mono-phenol and at least one C 1 -C 4 -alkylated bisphenol,   B) 1-5% by weight of a chelating agent for copper and zinc ions, and   C) 35-59% by weight of solvent selected from the group of aprotic amides with a chain length of C 2 -C 4  and/or cyclic ketals and/or dibasic esters with a chain length of C 4 -C 5 ,   
       where a sum of the constituents A), B) and C) is 100% by weight. 
     
     
         2 . The method as claimed in  claim 1 , wherein the mixture of at least one C 1 -C 4 -alkylated mono-phenol and at least one C 1 -C 4 -alkylated bisphenol is a mixture comprising 2,6-di-tert-butyl-4-methylphenol (BHT) and 2,2′-methylenebis(6-tert-butyl-4-methylphenol). 
     
     
         3 . The method as claimed in  claim 2 , wherein the chelating agent comprises aromatic triazoles which have a pH>6 in aqueous solution. 
     
     
         4 . The method as claimed in  claim 3 , wherein the aromatic, triazoles are benzotriazole and/or tolyltriazole. 
     
     
         5 . The method as claimed in  claim 1 , wherein the solvent is at least one aprotic amide. 
     
     
         6 . The method as claimed in  claim 5 , wherein the aprotic amide is N,N-dimethylacetamides, N,N-dimethylpropionylamide and/or N-methylpyrrolidone. 
     
     
         7 . The method as claimed in  claim 1 , wherein the cyclic ketals are the reaction products of glycerol with at least one C 1 - to C 6 -aldehyde and/or the reaction products of glycerol with at least one C 3 - to C 6 -ketone. 
     
     
         8 . The method as claimed in  claim 7 , wherein the cyclic ketals are 2,2-dimethyl-1,3-dioxolane-4-methanol, or a mixture of 2,2-dimethyl-1,3-dioxolane-4-methanol and 2-isobutyl-2-methyl-1,3-dioxolane-4-methanol. 
     
     
         9 . The method as claimed in  claim 2 , wherein a ratio of 2,6-di-tert-butyl-4-methylphenol (BHT) to 2,2′-methylenebis(6-tert-butyl-4-methylphenol is 1:10 to 2:1. 
     
     
         10 . The method as claimed in  claim 1 , wherein the component (A) further comprises 1-9% by weight of tert-butylhydroquinone. 
     
     
         11 . The method as claimed in  claim 1 , wherein the stabilized biodiesel is fuel. 
     
     
         12 . Oxygen-stabilized biodiesel comprising 0.005 to 0.5% by weight of stabilizer comprising:
 A) 40-60% by weight of a mixture of at least one C 1 -C 4 -alkylated mono-phenol and at least one C 1 -C 4 -alkylated bisphenol,   B) 0-5% by weight of chelating agent selected from the group of the aromatic triazoles, and   C) 35-59% by weight of solvent selected from the group of aprotic amides with a chain length of C 2 -C 4  and/or cyclic ketals and/or dibasic esters,   
       where a sum of the constituents A), B) and C) is 100% by weight. 
     
     
         13 . A fuel-stabilizer comprising:
 A) 40-60% by weight of a mixture of at least one C 1 -C 4 -alkylated mono-phenol and at least one C 1 -C 4 -alkylated bisphenol,   B) 0-5% by weight of chelating agent for copper and zinc ions, and   C) 35-59% by weight of solvent selected from the group of aprotic amides with a chain length of C 4 -C 6  and/or cyclic ketals and/or dibasic esters.   
     
     
         14 . The method as claimed in  claim 1 , wherein the composition comprises:
 45-55 wt % of the mixture of at least one C 1 -C 4 -alkylated mono-phenol and at least one C 1 -C 4 -alkylated bisphenol;   1.2-2.6% by weight, of the chelating agent, and   35-59% by weight of the solvent   
     
     
         15 . The method as claimed in  claim 14 , wherein:
 the mixture of at least one C 1 -C 4 -alkylated mono-phenol and at least one C 1 -C 4 -alkylated bisphenol is a mixture comprising 2,6-di-tert-butyl-4-methylphenol (BHT) and 2,2′-methylenebis(6-tert-butyl-4-methylphenol) at a ratio of 1:10 to 2:1;   the aromatic triazoles are benzotriazole and/or tolyltriazole; and   the solvent is N,N-dimethylacetamides, N,N-dimethylpropionylamide and/or N-methylpyrrolidone.   
     
     
         16 . The oxygen-stabilized biodiesel as claimed in  claim 12 , wherein the stabilizer comprises:
 45-55 wt % of the mixture of at least one C 1 -C 4 -alkylated mono-phenol and at least one C 1 -C 4 -alkylated bisphenol;   1.2-2.6% by weight, of the chelating agent, and 35-59% by weight of the solvent.   
     
     
         17 . The oxygen-stabilized biodiesel as claimed in  claim 16 , wherein:
 the mixture of at least on C 1 -C 4 -alkylated mono-phenol and at least one C 1 -C 4 -alkylated bisphenol is a mixture comprising 2,6-di-tert-butyl-4-methylphenol (BHT) and 2,2′-methylenebis(6-tert-butyl-4-methylphenol) at a ratio of 1:10 to 2:1;   the aromatic triazoles are benzotriazole and/or tolyltriazole; and   the solvent is N,N-dimethylacetamides, N,N-dimethylpropionylamide and/or N-methylpyrrolidone.