Asphaltene Dispersant Containing Lubricating Compositions

Abstract

The present invention relates to a lubricating composition, particularly marine diesel engine lubricating compositions, comprising: (a) an oil of lubricating viscosity; (b) an asphaltene dispersant comprising a cyclic headgroup that contains a nitrogen atom and at least one other heteroatom; and (c) a detergent derived from an alkyl phenol. The invention further provides methods of using such compositions in the operation of engine, particularly marine diesel engines.

1 . A lubricating composition comprising:
 (a) an oil of lubricating viscosity;   (b) an asphaltene dispersant comprising a cyclic headgroup that contains a nitrogen atom and at least one other heteroatom; and   (c) a detergent derived from an alkyl phenol.   
     
     
         2 . The composition of  claim 1  wherein the cyclic headgroup of the asphaltene dispersant contains at least one amidine group, urea group, guanidine group, or combinations thereof. 
     
     
         3 . The composition of  claim 1  wherein the headgroup of the asphaltene dispersant comprises a five-member ring, a six-member ring, or combinations thereof. 
     
     
         4 . The composition of any of the  claims 1  to  2  wherein the asphaltene dispersant comprises:
 (i) a compound represented by formula (I); 
 
       
         
           
           
               
               
           
         
         (ii) a compound represented by formula (II); 
       
       
         
           
           
               
               
           
         
         wherein, for each of the formulas above, each R 0  is independently a hydrogen or a hydrocarbyl group containing 1 to 250 carbon atoms; each R 1  is independently a hydrocarbyl group comprising 1 to 10 carbon atoms; each R 2  is independently hydrogen, a hydroxy group, or a hydrocarbyl group comprising 1 to 50 carbon atoms; Y is a carbon atom or a nitrogen atom; n is 1 or 2; and m is 0 or 1. 
       
     
     
         5 . The composition of  claim 1  wherein the asphaltene dispersant comprises:
 (i) a compound represented by formula (III); 
 
       
         
           
           
               
               
           
         
         (ii) a compound represented by formula (IV); 
       
       
         
           
           
               
               
           
         
         (iii) a compound represented by formula (V); 
       
       
         
           
           
               
               
           
         
         (iv) a compound represented by formula (VI); or 
       
       
         
           
           
               
               
           
         
         (v) combinations thereof; 
         wherein, for all the formulas above, each R 1  is independently a hydrocarbyl group comprising 1 to 10 carbon atoms; each R 2  is independently hydrogen or a hydrocarbyl group comprising 1 to 50 carbon atoms; each R 3  is independently a hydrocarbyl group comprising 1 to 50 carbon atoms; R 4  is a hydrocarbyl group containing 1 to 200 carbon atoms; and X is a hydrocarbylene group derived from an amine or a polyamine comprising 1 to 20 carbon atoms and 1 to 5 nitrogen atoms. 
       
     
     
         6 . The composition of  claim 4  wherein: R 2  is monounsaturated; or R 4  is derived from polyisobutylene; or X is derived from a polyalkylene polyamine; or combinations thereof. 
     
     
         7 . The composition of  claim 1  wherein the alkyl phenol detergent is present at 1 percent by weight or more in the overall composition. 
     
     
         8 . The composition of  claim 1  wherein the alkyl phenol detergent comprises a calcium phenate sulfide. 
     
     
         9 . The composition of  claim 1  wherein the total base number of the composition is at least 25 wherein at least 50 percent of the base number of the overall composition is delivered by the phenate detergent 
     
     
         10 . The composition of  claim 1  further comprising (d) a salicylate detergent wherein not more than 50 percent the TBN of the overall composition is delivered from the salicylate detergent. 
     
     
         11 . The composition of  claim 1  wherein the composition is a marine diesel engine lubricant or a power station combustion engine lubricant. 
     
     
         12 . A method of lubricating an internal combustion engine comprising supplying the lubricating composition of  claim 10  to an engine. 
     
     
         13 . The method of  claim 12  wherein the internal combustion engine is a marine diesel engine or a power station combustion engine. 
     
     
         14 . The method of  claim 13  wherein the marine diesel engine is a 4-stroke trunk piston engine; or wherein the marine diesel engine is a 2-stroke cross-head engine and the lubricating composition is a system oil. 
     
     
         15 . A process of preparing an asphaltene dispersant comprising the steps of reacting a substantially linear compound that contains at least one oxygen atom and at least two nitrogen atoms where the nitrogen atoms are separated by two or three carbon atoms with itself, such that the compound forms a ring structure containing the two nitrogen atoms. 
     
     
         16 . The process of  claim 15  wherein the substantially linear compound is derived from the reaction of a compound containing at least one —COOR group and a compound containing at least two nitrogen atoms where the nitrogen atoms are separated by two or three carbon atoms; wherein R can be a hydrogen or a hydrocarbyl group.