Additives for fuels and lubricants

Abstract

An additive compound comprising a derivative of particular fatty acids and polyamines has been found to be friction reducing, and particularly readily miscible in fuels and lubricants. The fatty acid has more than 12 carbon atoms and at least one carboxylic group. The polyamine residue has more than two nitrogen atoms. The mole ratio of the carboxylic groups to nitrogen atoms used to form the compound is greater than 0.8 carboxylic groups per 1 nitrogen atom.

1 . A method of reducing friction in an engine, by adding an additive compound to a fuel and/or lubricant which is employed by the engine, the additive compound comprising:
 (1) a fatty acid residue having more than 12 carbon atoms and at least one carboxylic group; and   (2) a polyamine residue having more than two nitrogen atoms;   wherein the mole ratio of the carboxylic groups to nitrogen atoms used to form the compound is greater than 0.8 carboxylic groups per 1 nitrogen atom.   
     
     
         2 . The method as claimed in  claim 1 , wherein the additive compound is a fatty acid amide or a salt of a fatty acid and a polyamine, or a mixture thereof. 
     
     
         3 . The method as claimed in  claim 1 , wherein the fatty acid is represented by the formula:
   R(COOH) n      wherein n is 1, 2, 3 or 4, and R represents a hydrocarbyl group having at least (13 minus n) carbon atoms.   
     
     
         4 . The method as claimed in  claim 3  wherein the fatty acid is a monocarboxylic acid having from 8 to 30 carbon atoms. 
     
     
         5 . The method as claimed in  claim 4  wherein the fatty acid is selected from tall oil fatty acid, oleic acid and isostearic acid. 
     
     
         6 . The method as claimed in  claim 1 , wherein the polyamine is an aliphatic polyamine having a hydrocarbyl group of 4 to 50 carbon atoms. 
     
     
         7 . The method as claimed in  claim 1 , wherein the additive compound is selected from the group consisting of:
 the reaction product of a monocarboxylic acid having more than 12 carbon atoms and at least one carboxylic group, and diethylene triamine, in a molar ratio (expressed as the reactant compounds) of at least 2.5 to 1;   the reaction product of a monocarboxylic acid having more than 12 carbon atoms and at least one carboxylic group, and triethylene tetramine, in a molar ratio (expressed as the reactant compounds) of at least 3.5 to 1; and   the reaction product of a monocarboxylic acid having more than 12 carbon atoms and at least one carboxylic group, and tetraethylene pentamine, in a molar ratio (expressed as the reactant compounds) of at least 4.5 to 1.   
     
     
         8 - 11 . (canceled) 
     
     
         12 . A compound which comprises:
 (1) a fatty acid residue having more than 12 carbon atoms and at least one carboxylic group; and   (2) a polyamine residue having more than two nitrogen atoms;   wherein the mole ratio of the carboxylic groups to nitrogen atoms used to form the compound is greater than 0.8 carboxylic groups per 1 nitrogen atom.   
     
     
         13 . A method of preparing a compound as claimed in  claim 12 , comprising reacting:
 (1) a fatty acid having more than 12 carbon atoms and at least one carboxylic group, and   (2) a polyamine having more than two nitrogen atoms;   at a mole ratio of greater than 0.8 carboxylic groups per 1 nitrogen atom.   
     
     
         14 . A fuel composition comprising a fuel and a compound as claimed in  claim 12 . 
     
     
         15 . An additive composition containing a solvent and a compound as claimed in  claim 12 , the additive composition being adapted for addition into a fuel, with dilution therein of said compound. 
     
     
         16 . A method of increasing the efficiency of an engine utilising a fuel and/or lubricant, by adding an additive compound to the fuel and/or lubricant which is employed by the engine, the additive compound comprising:
 (1) a fatty acid residue having more than 12 carbon atoms and at least one carboxylic group; and   (2) a polyamine residue having more than two nitrogen atoms;   wherein the mole ratio of the carboxylic groups to nitrogen atoms used to form the compound is greater than 0.8 carboxylic groups per 1 nitrogen atom.   
     
     
         17 . A method of improving the friction performance of an engine lubricant, by adding an additive compound to the lubricant which is employed by the engine, the additive compound comprising:
 (1) a fatty acid residue having more than 12 carbon atoms and at least one carboxylic group; and   (2) a polyamine residue having more than two nitrogen atoms;   wherein the mole ratio of the carboxylic groups to nitrogen atoms used to form the compound is greater than 0.8 carboxylic groups per 1 nitrogen atom.   
     
     
         18 . The method as claimed in  claim 6 , wherein the aliphatic polyamine has a hydrocarbyl group of 4 to 20 carbon atoms. 
     
     
         19 . The method as claimed in  claim 7 , wherein the monocarboxylic acid is TOFA.