Carboxylic acid derivatives as friction modifiers in fuels

Abstract

The present invention provides an additive composition and a fuel composition for use in internal combustion engines, where the compositions comprise a friction modifier which is the condensation product of (i) certain carboxylic acids and (ii) a mixture comprising a branched alcohol or branched amine having 1 to about 150 carbon atoms, or combinations thereof wherein the fuel composition improves the fuel economy of the engine in which it is used and where the fuel additive composition has improved low temperature storage stability compared to compositions containing other fatty acid-derived friction modifiers.

1 . A fuel additive composition comprising:
 (a) an ashless friction modifier represented by Formula I;   (b) an optional solvent; and   (c) one or more optional additional performance additives;   
       
         
           
           
               
               
           
         
       
       wherein:
 Y and Y′ are independently —O—, >NH, >NR 3 , or an imide group formed by taking together both Y and Y′ groups and forming a R 1 —N< group between two >C═O groups; 
 X is independently —Z—O—Z′—, >CH 2 , >CHR 4 , >CR 4 R 5 , >C(OH)(CO 2 R 2 ), >C(CO 2 R 2 ) 2 , >CHOR 6 , or >CHCO 2 R 2 , 
 Z and Z′ are independently >CH 2 , >CHR 4 , >CR 4 R 5 , >C(OH)(CO 2 R 2 ), or >CHOR 6 ; 
 n is 0 to 10, or 1 to 8, or 1 to 6, or 2 to 6, or 2 to 4, with the provisos that when n is 1, X is not >CH 2 , and when n is 2, both X′s are not simultaneously >CH 2 ; 
 m is 0 or 1; 
 R 1  is independently hydrogen or a hydrocarbyl group, typically containing 1 to 150, 4 to 30, or 6 to 20, or 10 to 20, or 11 to 18, or 8 to 10 carbon atoms, with the proviso that when R 1  is hydrogen, m is 0, and n is more than or equal to 1; 
 R 2  is a hydrocarbyl group, typically containing 1 to 150, 4 to 30, or 6 to 20, or 10 to 20, or 11 to 18, or 8 to 10 carbon atoms; 
 R 3 , R 4  and R 5  are independently hydrocarbyl groups, hydroxyl-containing hydrocarbyl groups, or carboxyl-containing hydrocarbyl groups; and 
 R 6  is hydrogen or a hydrocarbyl group, typically containing 1 to 150, or 4 to 30 carbon atoms. 
 
     
     
         2 . The additive composition of  claim 1 , wherein the friction modifier of Formula I is derived from at least one of a hydroxy-polycarboxylic acid di-ester, a hydroxy-polycarboxylic acid di-amide, a hydroxy-polycarboxylic acid di-imide, a hydroxy-polycarboxylic acid ester-amide, a hydroxy-polycarboxylic acid ester-imide, and a hydroxy-polycarboxylic acid imide-amide. 
     
     
         3 . The additive composition of  claim 1 , wherein Formula I defines m as 0 or 1, n as 1 to 2, X is >CHOR 6 , and R 1 , R 2  and R 6  are independently hydrogen or hydrocarbyl groups containing 4 to 30 carbon atoms. 
     
     
         4 . The additive composition of  claim 1  wherein component (a) is the condensation product of (i) a material represented by Formula II and (ii) a mixture comprising a branched alcohol or branched amine having 1 to about 150 carbon atoms, or combinations thereof; 
       
         
           
           
               
               
           
         
       
       wherein
 each X is independently —Z—O—Z—, >CH 2 , >CR 1 R 2 , >C(OH)(CO 2 R 2 ), or >CHOR 2 ; and wherein each Z is independently >CH 2 , >CR 1 R 2 , >C(OH)(CO 2 R 2 ), or >CHOR 2 ; 
 m is 0 or 1; n is 1 to 10, with the proviso that when n=1, X is not >CH 2 , and when n=2, both X′s are not >CH 2 ; and 
 each R 1  and R 2  are independently hydrogen or a hydrocarbyl groups. 
 
     
     
         5 . The additive composition of  claim 4  wherein X in Formula II is >CHOR 2 , m is 1, and n is 2 or wherein (X) n  in Formula II is —CH 2 —C(OH)(CO 2 R 2 )—CH 2 — and m is 1. 
     
     
         6 . The additive composition of  claim 4  wherein component (a)(i) is represented by Formula III, Formula IV, or a combination thereof: 
       
         
           
           
               
               
           
         
       
       wherein each R 3  is independently H, or a hydrocarbyl group, or wherein the R 3  groups together form a ring; 
       
         
           
           
               
               
           
         
       
       wherein each R 3  is independently H, or a hydrocarbyl group. 
     
     
         7 . The additive composition of  claim 4  wherein component (a)(ii) comprises a mixture of one or more branched alcohols or branched amines, or combinations thereof wherein the branched alcohols or branched amines contain from 6 to 16 carbon atoms. 
     
     
         8 . The additive composition of  claim 4  wherein at least 25 percent by weight of component (a)(ii) are branched alcohols, branched amines or combinations thereof. 
     
     
         9 . The additive composition of  claim 4  wherein the component (a)(ii) comprises alcohols selected from the group consisting of: 2-methyl-1-pentanol, 2-ethylhexanol, 2-octanol, isooctyl alcohol, isotridecyl alcohol, or combinations thereof. 
     
     
         10 . The additive composition of  claim 1 , wherein component (a) is present in an amount of about 1 ppm to about 10000 ppm. 
     
     
         11 . A fuel composition suitable for use in an internal combustion engine, comprising:
 (a) an friction modifier represented by Formula I; and   (b) a fuel:   
       
         
           
           
               
               
           
         
       
       wherein:
 Y and Y′ are independently —O—, >NH, >NR 3 , or an imide group formed by taking together both Y and Y′ groups and forming a R 1 —N< group between two >C═O groups; 
 X is independently —Z—O—Z′—, >CH 2 , >CHR 4 , >CR 4 R 5 , >C(OH)(CO 2 R 2 ), >C(CO 2 R 2 ) 2 , >CHOR 6 , or >CHCO 2 R 2 . 
 Z and Z′ are independently >CH 2 , >CHR 4 , >CR 4 R 5 , >C(OH)(CO 2 R 2 ), or >CHOR 6 ; 
 n is 0 to 10, or 1 to 8, or 1 to 6, or 2 to 6, or 2 to 4, with the provisos that when n is 1, X is not >CH 2 , and when n is 2, both X′s are not simultaneously >CH 2 ; 
 m is 0 or 1; 
 R 1  is independently hydrogen or a hydrocarbyl group, typically containing 1 to 150, 4 to 30, or 6 to 20, or 10 to 20, or 11 to 18, or 8 to 10 carbon atoms, with the proviso that when R 1  is hydrogen, m is 0, and n is more than or equal to 1; 
 R 2  is a hydrocarbyl group, typically containing 1 to 150, 4 to 30, or 6 to 20, or 10 to 20, or 11 to 18, or 8 to 10 carbon atoms; 
 R 3 , R 4  and R 5  are independently hydrocarbyl groups, hydroxyl-containing hydrocarbyl groups, or carboxyl-containing hydrocarbyl groups; and 
 R 6  is hydrogen or a hydrocarbyl group, typically containing 1 to 150, or 4 to 30 carbon atoms. 
 
     
     
         12 . A method of operating an internal combustion engine, comprising supplying to said engine a fuel composition comprising:
 (a) a friction modifier represented by Formula I; and   (b) a fuel;   
       
         
           
           
               
               
           
         
       
       wherein:
 Y and Y′ are independently —O—, >NH, >NR 3 , or an imide group formed by taking together both Y and Y′ groups and forming a R 1 —N< group between two >C═O groups; 
 X is independently —Z—O—Z′—, >CH 2 , >CHR 4 , >CR 4 R 5 , >C(OH)(CO 2 R 2 ), >C(CO 2 R 2 ) 2 , >CHOR 6 , or >CHCO 2 R 2 . 
 Z and Z′ are independently >CH 2 , >CHR 4 , >CR 4 R 5 , >C(OH)(CO 2 R 2 ), or >CHOR 6 ; 
 n is 0 to 10, or 1 to 8, or 1 to 6, or 2 to 6, or 2 to 4, with the provisos that when n is 1, X is not >CH 2 , and when n is 2, both X′s are not simultaneously >CH 2 ; 
 m is 0 or 1; 
 R 1  is independently hydrogen or a hydrocarbyl group, typically containing 1 to 150, 4 to 30, or 6 to 20, or 10 to 20, or 11 to 18, or 8 to 10 carbon atoms, with the proviso that when R 1  is hydrogen, m is 0, and n is more than or equal to 1; 
 R 2  is a hydrocarbyl group, typically containing 1 to 150, 4 to 30, or 6 to 20, or 10 to 20, or 11 to 18, or 8 to 10 carbon atoms; 
 R 3 , R 4  and R 5  are independently hydrocarbyl groups, hydroxyl-containing hydrocarbyl groups, or carboxyl-containing hydrocarbyl groups; and 
 R 6  is hydrogen or a hydrocarbyl group, typically containing 1 to 150, or 4 to 30 carbon atoms.