Fuels derived from animal or vegetable oil sources

Abstract

There is provided a method of providing an improved biofuel, by the presence of an additive which is the reaction product of (i) a compound containing the segment —NR1R2 where R1 represents a group containing from 4 to 44 carbon atoms and R2 represents a hydrogen atom or a group R1 (for example di-hydrogenated tallow amine) and (ii) a carboxylic acid having from 1 to 4 carboxylic acid groups or an acid anhydride or acid chloride thereof (for example phthalic acid or phthalic anhydride). The additives described combat problems arising from precipitation at temperatures above the cloud point.

1 . A method of providing an improved Bx fuel, by the presence of an additive which is the reaction product of (i) a compound containing the segment —NR 1 R 2  where R 1  represents a group containing from 4 to 44 carbon atoms and R 2  represents a hydrogen atom or a group 10, and (ii) a carboxylic acid, wherein the carboxylic acid is a benzene dicarboxylic acid selected from isophthalic acid, terephthalic acid and phthalic acid or an acid anhydride or acid halide thereof. 
     
     
         2 . The method as claimed in  claim 1 , wherein the group R 1  is a predominantly straight chain, substantially saturated group comprising from 10 to 24 carbon atoms. 
     
     
         3 . The method as claimed in  claim 1 , in which the group R 2  is a group containing from 4 to 44 carbon atoms or is a predominantly straight chain, substantially saturated group comprising from 10 to 24 carbon atoms. 
     
     
         4 . The method as claimed in  claim 3 , in which the compound (i) is a secondary amine of formula HNR 1 R 2  where R 1  and R 2  are as defined in  claim 3 ; or is an ammonium salt having the cation +NR 1 R 2 R 3 R 4  where R 1  and R 2  are as defined in  claim 3  and R 3  and R 4  independently represent a C(1-4) alkyl group. 
     
     
         5 .- 6 . (canceled) 
     
     
         7 . The method as claimed in  claim 1 , in which the molar ratio of compound (i) to acid anhydride or acid halide (ii) is such that at least 50% of the acid groups are reacted in the reaction between the compounds (i) and (ii). 
     
     
         8 . The method as claimed in  claim 1 , in which compound (i) is a secondary amine and/or quaternary ammonium salt and compound (ii) is a dicarboxylic acid, or an acid anhydride or acid halide thereof, wherein the molar ratio of compound(s) (i) to acid, acid anhydride or acid halide (ii) is at least 1:1. 
     
     
         9 . The method as claimed in  claim 1 , wherein the said additive is present in the Bx fuel in an amount of from 5 mg/kg fuel to 500 mg/kg fuel. 
     
     
         10 . The method as claimed in  claim 1 , in which the Bx fuel is a blended fuel comprising a fuel component derived from an animal or a vegetable oil source and a fuel component derived from a mineral source. 
     
     
         11 . The method as claimed in  claim 10 , wherein the Bx fuel comprises one or more compounds which improve the flow properties of the fuel derived from the mineral source at a temperature below the cloud point of the Bx fuel. 
     
     
         12 .- 14 . (canceled) 
     
     
         15 . A Bx fuel having improved flow properties above the cloud point of the Bx fuel, the fuel comprising an additive which is the reaction product of (i) a compound containing the segment —NR 1 R 2  where R 1  represents a group containing from 4 to 44 carbon atoms and R 2  represents a hydrogen atom or a group R 1 , and (ii) a carboxylic acid, wherein the carboxylic acid is a benzene dicarboxylic acid selected from isophthalic acid, terephthalic acid and phthalic acid or an acid anhydride or acid halide thereof. 
     
     
         16 . An additive composition comprising an additive which is the reaction product of (i) a compound containing the segment —NR 1 R 2  where R 1  represents a group containing from 4 to 44 carbon atoms and R 2  represents a hydrogen atom or a group R 1 , and (ii) a carboxylic acid, wherein the carboxylic acid is a benzene dicarboxylic acid selected from isophthalic acid, terephthalic acid and phthalic acid or an acid anhydride or acid halide thereof in a solvent. 
     
     
         17 . The method as claimed in  claim 1 , in which the benzene dicarboxylic acid is phthalic acid or an acid anhydride or acid halide thereof. 
     
     
         18 . The Bx fuel as claimed in  claim 15 , in which the benzene dicarboxylic acid is phthalic acid or an acid anhydride or acid halide thereof. 
     
     
         19 . The additive composition as claimed in  claim 16 , in which the benzene dicarboxylic acid is phthalic acid or an acid anhydride or acid halide thereof. 
     
     
         20 . The method as claimed in  claim 1 , wherein at least 75% of the acid groups are reacted in the reaction between the compounds (i) and (ii). 
     
     
         21 . The method as claimed in  claim 1 , wherein at least 90% of the acid groups are reacted in the reaction between the compounds (i) and (ii). 
     
     
         22 . The method as claimed in  claim 1 , wherein the molar ratio of compound(s) (i) to acid, acid anhydride or acid halide (ii) is at least 1.5:1. 
     
     
         23 . The method as claimed in  claim 1 , wherein the said additive is present in the Bx fuel in an amount of from 10 mg/kg fuel to 80 mg/kg fuel. 
     
     
         24 . The method as claimed in  claim 1 , wherein the said additive is present in the Bx fuel in an amount of from 20 mg/kg fuel to 60 mg/kg fuel. 
     
     
         25 . The method as claimed in  claim 1 , wherein the said additive is present in the Bx fuel in an amount of from 30 mg/kg fuel to 45 mg/kg fuel. 
     
     
         26 . The method as claimed in  claim 1 , in which the Bx fuel is a blended fuel comprising a fuel component derived from a vegetable oil source and a fuel component derived from a mineral source.