Diesel fuel compositions

Abstract

A diesel fuel composition comprising a first additive (i) comprising a quaternary ammonium salt and a second additive (ii) comprising a Mannich reaction product; wherein the quaternary ammonium salt additive (i) is formed by the reaction a quaternising agent which is not an ester and a compound formed by the reaction of a hydrocarbyl-substituted acylating agent and an amine of formula (B1) or (B2): wherein R 2 and R 3 are the same or different alkyl, alkenyl or aryl groups having from 1 to 22 carbon atoms; X is a bond or alkylene group having from 1 to 20 carbon atoms; n is from 0 to 20; m is from 1 to 5; and R 4 is hydrogen or a C 1 to C 22 alkyl group; and wherein the Mannich reaction product additive (ii) is the product of a Mannich reaction between: (d) an aldehyde; (e) an amine; and (f) a substituted phenol; wherein the phenol is substituted with at least one branched hydrocarbyl group having a molecular weight of between 200 and 3000.

1 . A diesel fuel composition comprising a first additive (i) comprising a quaternary ammonium salt and a second additive (ii) comprising a Mannich reaction product; wherein the quaternary ammonium salt additive (i) is formed by the reaction a quaternising agent which is not an ester and a compound formed by the reaction of a hydrocarbyl-substituted acylating agent and an amine of formula (B1) or (B2): 
       
         
           
           
               
               
           
         
       
       wherein R 2  and R 3  are the same or different alkyl, alkenyl or aryl groups having from 1 to 22 carbon atoms; X is a bond or alkylene group having from 1 to 20 carbon atoms; n is from 0 to 20; 
       m is from 1 to 5; and R 4  is hydrogen or a C to C 2-2  alkyl group; and wherein the Mannich reaction product additive (ii) is the product of a Mannich reaction between:
 (a) an aldehyde; 
 (b) an amine; and 
 (c) a substituted phenol; 
 
       wherein the phenol is substituted with at least one branched hydrocarbyl group having a molecular weight of between 200 and 3000. 
     
     
         2 . The diesel fuel composition according to  claim 1  wherein the quaternising agent is selected from selected from dialkyl sulfates, benzyl halides, hydrocarbyl substituted carbonates, hydrocarbyl substituted epoxides in combination with an acid, alkyl halides, alkyl sulfonates, sultones, hydrocarbyl substituted phosphates, hydrocarbyl, substituted borates, alkyl nitrites, alkyl nitrates, N-oxides or mixtures thereof. 
     
     
         3 . The diesel fuel composition according to  claim 2  wherein the quaternising agent is selected from selected from dialkyl sulfates, benzyl halides, hydrocarbyl substituted carbonates and hydrocarbyl substituted epoxides in combination with an acid. 
     
     
         4 . The diesel fuel composition according to  claim 1  wherein the hydrocarbyl substituted acylating agent is reacted with a diamine compound of formula (B1). 
     
     
         5 . The diesel fuel composition according to  claim 1  wherein additive (i) is a salt of tertiary amine prepared from dimethylaminopropylamine and a polyisobutylene-substituted succinic anhydride. 
     
     
         6 . The diesel fuel composition according to  claim 1  wherein component (a) used to prepare additive (ii) is formaldehyde. 
     
     
         7 . The diesel fuel composition according to  claim 1  wherein component (b) used to prepare additive (ii) is a (poly)ethylene polyamine. 
     
     
         8 . The diesel fuel composition according to  claim 1  wherein component (c) used to prepare additive (ii) is a polyisobutylene-substituted phenol. 
     
     
         9 . The diesel fuel composition according to  claim 1  wherein in the Mannich reaction used to form additive (ii) the molar ratio of component (a) to component (b) is 2.2-1.01:1; the molar ratio of component (a) to component (c) is 1.99-1.01:1 and the molar ratio of component (h) to component (c) is 1:1.01-1.99. 
     
     
         10 . The diesel fuel composition according to  claim 9  wherein in the reaction used to make the Mannich additive the molar ratio of component (a) to component (b) is 2-1.4:1, the molar ratio of component (a) to component (c) is 1.7-1.1:1 and the molar ratio of component (b) to component (c) is 1:1.1-1.7. 
     
     
         11 . The diesel fuel composition according to  claim 1  wherein the diesel fuel comprises a non-renewable Fischer Tropsch fuel and/or biodiesel. 
     
     
         12 . The diesel fuel composition according to  claim 1  which further comprises a fuel-borne catalyst which includes a metal selected from iron, cerium, group I and group II metals, platinum, manganese and mixtures thereof. 
     
     
         13 . An additive package which, upon addition to a diesel fuel, provides a composition as claimed in  claim 1 . 
     
     
         14 . A method of operating a diesel engine, the method comprising combusting in the engine a composition as claimed in  claim 1 . 
     
     
         15 - 19 . (canceled)