Di-secondary alkyl hindered phenol antioxidants

Abstract

A lubricating composition containing the reaction product (a) of an aldehyde, amine and a di-secondary alkyl hindered phenol and at least one additive selected from the group consisting of hydrocarbyl diphenylamines, sterically hindered phenols other than component (a), metal hydrocarbyl dithiophosphates, sulphurised olefins and mixtures thereof. The composition has antioxidant properties for internal combustion engines without the bioaccumulation of tris-tert-butyl phenol.

What is claimed is:  
     
         1 . A lubricating oil composition comprising: 
 a. a Mannich product formed from the reaction of an aldehyde, ammonia or an amine and a di-secondary alkyl hindered phenol;    b. at least one additive selected from the group consisting of hydrocarbyl diphenylamines, sterically hindered phenols other than component (a), metal hydrocarbyl dithiophosphates, molybdenum dithiocarbamates, sulphurised olefins and mixtures thereof; and    c. an oil of lubricating viscosity.    
     
     
         2 . The composition of  claim 1 , wherein the aldehyde is represented by the formula R 5 —C(O)H, wherein R 5  contains hydrogen or hydrocarbyl with 1 to about 7 carbon atoms.  
     
     
         3 . The composition of  claim 1 , wherein the amine is represented by the formula R 1 R 2 N—H, wherein R 1  and R 2  are independently hydrogen, hydrocarbyl groups or mixtures thereof.  
     
     
         4 . The composition of  claim 1 , wherein the di-secondary alkyl hindered phenol is represented by the formula:  
       
         
           
           
               
               
           
         
       
       wherein R 6 , R 7 , R 8  and R 9  are independently alkyl groups with 1 to about 6 carbon atoms; or adjacent group R 6 -R 7  and/or R 8 -R 9  together form cycloalkyl groups with about 3 to about 11 carbon atoms; or mixtures thereof.  
     
     
         5 . The composition of  claim 1 , wherein the Mannich product is represented by the formulae:  
       
         
           
           
               
               
           
         
       
       wherein R 1  and R 2  are independently hydrogen or hydrocarbyl groups; each R 5  is independently contains hydrogen or a hydrocarbyl group with 1 to about 7 carbon atoms; and R 6  R 7 , R 8  and R 9  are independently alkyl groups with 1 to about 6 carbon atoms; or adjacent group R 6 -R 7  and/or R 8 -R 9  together form cycloalkyl groups with about 3 to about 11 carbon atoms or mixtures thereof.  
     
     
         6 . The composition of  claim 1  wherein the oil of lubricating viscosity comprises an API Group I, II, III, IV, or V oil or mixtures thereof.  
     
     
         7 . The composition of  claim 1 , wherein the hydrocarbyl diphenylamine is represented by the formula:  
       
         
           
           
               
               
           
         
       
       wherein R 10  and R 11  are hydrocarbyl groups containing 1 to about 24 carbon atoms, and each z is independently 0, 1, 2, or 3, provided that at least one aromatic ring contains a hydrocarbyl group.  
     
     
         8 . The composition of  claim 1 , wherein the sterically hindered phenol is represented by the formula:  
       
         
           
           
               
               
           
         
       
       wherein R 12  and R 13  are independently branched or linear alkyl groups containing 1 to about 24 carbon atoms; and Q is hydrogen, hydrocarbyl, a bridging group linking to a second aromatic group or mixtures thereof.  
     
     
         9 . The composition of  claim 1 , wherein the metal hydrocarbyl dithiophosphate is a metal salt of compounds represented by the formula:  
       
         
           
           
               
               
           
         
       
       R 25  and R 26  are independently hydrogen, hydrocarbyl groups or mixtures thereof, provided that at least one of R 25  and R 26  is a hydrocarbyl group; M is a metal, and n is an integer equal to the available valence of M.  
     
     
         10 . The composition of  claim 1 , wherein the molybdenum dithiocarbamate is represented by the formula:  
       
         
           
           
               
               
           
         
       
       wherein R 27  and R 28  are independently hydrogen or hydrocarbyl groups, aminoalkyl groups, acylated aminoalkyl groups or mixtures thereof containing 3 to 20 carbon atoms; and m and n are positive integers whose combined total is 4.  
     
     
         11 . The composition of  claim 1 , wherein the sulphurised olefin is the reaction product of an aliphatic olefin having about 4 to about 36 carbon atoms with a  
       
         
           
           
               
               
           
         
       
       wherein R 29 , R 30 , R 31  and R 32  are independently hydrogen or hydrocarbyl.  
     
     
         12 . The composition of  claim 1  further comprising at least one additive selected from the group consisting of metal deactivators, detergents, dispersants, antiwear agents, corrosion inhibitors, antiscuffing agents, extreme pressure agents, foam inhibitors, demulsifiers, friction modifiers, viscosity modifiers, pour point depressants and mixtures thereof.  
     
     
         13 . A process to prepare a composition comprising: 
 a) reacting a di-secondary alkyl phenol with an aldehyde and amine to form a Mannich product; and    b) mixing the Mannich product with base oil, compounds with antioxidant properties, optionally optional additives or mixtures thereof.    
     
     
         14 . The process of  claim 13  when using solvent, further comprising the step of separating the Mannich product from the organic solvent.  
     
     
         15 . The process of  claim 13  further comprising adding of at least one additive selected from the group consisting of metal deactivators, detergents, dispersants, antiwear agents, corrosion inhibitors, antiscuffing agents, extreme pressure agents, foam inhibitors, demulsifiers, friction modifiers, viscosity modifiers, pour point depressants and mixtures thereof.  
     
     
         16 . The process of  claim 1 , wherein the base oil is present in a sufficient amount to form a concentrate.  
     
     
         17 . The process of  claim 12 , wherein the organic solvent is selected from aliphatic hydrocarbons, alicyclic hydrocarbons or aromatic hydrocarbons or mixtures thereof, provided the boiling point of the solvent is above 100° C.  
     
     
         18 . A method for lubricating an internal combustion engine, comprising supplying thereto a lubricant comprising the composition of  claim 1 .  
     
     
         19 . The method of  claim 18 , wherein the internal combustion engine is a diesel fuelled engine, a gasoline fuelled engine, natural gas fuelled engine or a mixed gasoline/alcohol fuelled engine.