Biodiesel containing non-phenolic additives and thereby possessing enhanced oxidative stability and low acid number

Abstract

Biodiesel compositions are provided, containing non-phenolic additives that improve the oxidative stability and lower the acid number. The invention further provides non-phenolic additive concentrate compositions and diesel fuel compositions containing the above biodiesel compositions.

1 ) A biodiesel composition of improved oxidation stability and low acid number, comprising:
 a. A major amount of biodiesel fuel suitable for use in a compression ignition engine and consisting of a mixture of methyl or ethyl esters of fatty acids derived from fats and oils of vegetable or animal origin, and   b. A minor amount of a substance or mixture of substances which is the product of the chemical reaction between Component 1 and Component 2, wherein:   Component 1 is a carboxylic acid, a carboxylic ester or a mixture of carboxylic acids and/or esters having the chemical formula:   
       
         
           
           
               
               
           
         
         Where: 
         R 1  is a straight or branched alkyl or hydroxyalkyl group having the formula C m H 2m−x−k+1 (OH) k  (m being an integer from 1 to 30, x being 0, 2, 4, or 6 but always fulfilling the relation x<m, and k being 0 or 1), a cyclohexyl group, a phenyl group, or a substituted phenyl group bearing a C 1  to C 12  alkyl substituent, and R 2  is hydrogen, methyl, or ethyl. 
         Component 2 is a non-aromatic diamine or polyamine having at least one primary nitrogen atom separated by two or three carbon atoms from another nitrogen atom which is primary or secondary, or a mixture of such diamines and/or polyamines having the chemical formula: 
       
       
         
           
           
               
               
           
         
         Where: 
         n is 0 or 1, R 3  and R 4  are hydrogen, methyl, or taken together are part of a cyclohexane ring, R 5  is hydrogen, or methyl, and R 6  is hydrogen, a straight or branched alkyl group having the formula C m H 2m−x+1  (m being an integer from 1 to 22 and x being 0, 2, 4, or 6 but always fulfilling the relation x<m), or an amine moiety having the formula —CH 2 CH 2 (CH 2 ) p NH[CH 2 CH 2 (CH 2 ) p NH] q H with p being 0 or 1 and q being 0, 1, 2, 3, or 4. 
       
     
     
         2 ) A biodiesel composition according to  claim 1 , where Component 2 is N-(2-aminoethyl-1,2-ethanediamine), also known as Diethylene Triamine or DETA. 
     
     
         3 ) A biodiesel composition according to  claim 1 , where Component 2 is the mixed polyamine Triethylene Tetramine or TETA. 
     
     
         4 ) A biodiesel composition according to  claim 1 , where Component 2 is the mixed polyamine Tetraethylene Pentamine or TEPA. 
     
     
         5 ) A biodiesel composition according to  claim 1 , where Component 1 is a mixture of fatty acids obtained by the saponification of a vegetable or animal oil or fat or a mixture of such oils or fats. 
     
     
         6 . A biodiesel composition according to  claim 1 , where the substance or mixture of substances described in paragraph (b) is present at a concentration between 0.01 percent by weight and 1 percent by weight. 
     
     
         7 ) A biodiesel composition according to  claim 1 , which also contains an appropriate amount of additives for improving some of its properties such as ignition quality, cold flow characteristics, resistance to microbial degradation, tribological characteristics, and the like. 
     
     
         8 ) An additive concentrate composition comprising
 a. at least 5 percent by weight of a substance or mixture of substances which is the product of the chemical reaction between Component 1 and Component 2 according to  claim 1 , and   b. up to 95 percent by weight of a diluent consisting of a liquid mixture of hydrocarbons having a flash point of at least 100° C. and a final boiling point of less than 340° C., a biodiesel fuel suitable for use in a compression ignition engine and consisting of a mixture of methyl or ethyl esters of fatty acids derived from fats and oils of vegetable or animal origin, or a blend of liquid hydrocarbons and biodiesel fuel as defined hereinabove.   
     
     
         9 ) A diesel fuel composition comprising:
 Conventional diesel fuel derived from petroleum or other mineral fuels and suitable for use in a compression ignition engine, to the extent of 99 percent or less by volume, and   A biodiesel composition according to  claim 1 , to the extent of one percent or more by volume.   
     
     
         10 ) A diesel fuel composition according to  claim 9 , which also contains an appropriate amount of additives for improving some of its properties such as ignition quality, cold flow characteristics, resistance to microbial degradation, tribological characteristics, and the like. 
     
     
         11 ) A method for the preparation of the substance or mixture of substances according to paragraph (b) of  claim 1 , consisting of the addition to the reaction mixture of a strong organic base, such as tetramethylguanidine, to the extent of 0.1% to 5% by weight in relation to the weight of Component 2 described in  claim 1 .