Overbased alkylated arylalkyl sulfonates

Abstract

An overbased alkylated arylalkyl sulfonate is easy to prepare and is useful as a detergent in various lubricant applications.

What is claimed is: 
     
         1 . A lubricant composition comprising:
 an oil of lubricating viscosity; and   an overbased salt in an amount from about 0.3 to about 8% by weight comprising:   an anionic portion represented by   
       
         
           
           
               
               
           
         
       
       wherein each R 1  is independently H or an alkyl group of 1 to 4 carbon atoms; R 2 , R 3 , and R 4  are independently H or hydrocarbyl groups, R 5  is a group represented by —CR 1 R 7 (CR 1   2 ) o CHR 1   2 , R 6  is H or —(CR 1   2 ) m CHR 1   2 , and R 7  is H or —(CR 1   2 ) p CHR 1   2 ; m, n, o, and p are numbers such that m+n is 4 to 28 and o+p is 3 to 27, provided that when R 6  is H, m is defined as 0 and n is 5 to 29 and when R 7  is H, p is defined as 0 and o is 4 to 28; and wherein the total number of carbon atoms in said anionic portion is at least 26; and
 a metal or amine or ammonium cation; 
 wherein the overbased salt has a cation content in excess of that which would be present for neutralization according to the stoichiometry of the cation and of said anionic portion; 
 and wherein the metal ratio of the overbased salt is from about 1.1 to about 10. 
 
     
     
         2 . The lubricating composition of  claim 1 , wherein the anionic portion of the overbased salt is represented by 
       
         
           
           
               
               
           
         
       
       wherein R 5  is represented by —CHR 7 (CH 2 ) o CH 3  wherein R 7  is H or —(CH 2 ) p CH 3  and o+p is 3 to 27. 
     
     
         3 . The lubricating composition of  claim 1 , wherein the overbased salt a TBN of about 10 to about 1100 on an oil-free basis. 
     
     
         4 . The lubricating composition of  claim 1  wherein the overbased salt is a carbonated metal salt. 
     
     
         5 . The lubricating composition of  claim 1  wherein the cation of the overbased salt comprises a calcium, magnesium, or sodium cation. 
     
     
         6 . The lubricating composition of  claim 1  wherein the R 1  groups in the SO 3   −  containing substituent of the overbased salt are H and n+m is about 8 to about 18 
     
     
         7 . The lubricating composition of  claim 1 , wherein the R 1  groups in R 5  of the overbased salt are H and o+p is about 7 to about 17. 
     
     
         8 . The lubricant composition of  claim 1  wherein one or two of R 2 , R 3 , and R 4  of the overbased salt are methyl groups. 
     
     
         9 . The lubricant composition of  claim 1  wherein the anion portion of the overbased salt comprises a species represented by 
       
         
           
           
               
               
           
         
       
       and isomers thereof, wherein q is 5 or 6 and R 5  is a linear alkyl group containing 14 to 16 carbon atoms. 
     
     
         10 . The lubricant composition of  claim 1  wherein the overbased salt comprises about 90 percent or more by weight of the total detergents in the lubricant composition. 
     
     
         11 . The lubricant composition of  claim 1  further comprising at least one dispersant, friction modifier, antiwear agent, antioxidant, viscosity modifier, or additional overbased salt. 
     
     
         12 . A method for lubricating a mechanical device, comprising supplying thereto the lubricant composition of  claim 1 . 
     
     
         13 . The method of  claim 12  wherein the mechanical device comprises an internal combustion engine, a transmission, a gear, or a hydraulic system. 
     
     
         14 . A method of preparing a lubricating composition comprising:
 combining an oil of lubricating viscosity; and   an overbased salt in an amount of from about 0.3 to about 8 wt %, comprising a sulfonic acid represented by   
       
         
           
           
               
               
           
         
       
       where n, m, o, p, R 1 , R 2 , R 3 , R 4 , R 5 , and R 6  are as defined in  claim 1 , or a reactive equivalent thereof, with a stoichiometric excess of a basic metal compound or amine compound or ammonia, the overbased salt having a metal ratio of from about 1.1 to about 10. 
     
     
         15 . The method of  claim 14  wherein the sulfonic acid or reactive equivalent thereof is reacted with an excess of calcium hydroxide, calcium oxide, magnesium hydroxide, magnesium oxide, sodium hydroxide, or sodium oxide.