Lubricant base oil and lubricant composition

Abstract

A lubricating base oil includes at least one of ionic liquids containing a compound represented by a formula (1): Z + A − , in which Z + represents a cation and A − represents an anion, in which Z + is a cyclic quaternary ammonium ion having two different side chains and A − is a conjugated amide ion.

1 . A lubricating base oil comprising an ionic liquid comprising a compound of formula (1):
   Z + A −   (1)
   wherein Z +  is a cyclic quaternary ammonium cation having two different side chains and   A −  is a conjugated amide anion.   
     
     
         2 . The lubricating base oil of  claim 1 , wherein A −  is of formula (2): 
       
         
           
           
               
               
           
         
         n is an integer of from 1 to 4, 
         m is an integer of from 1 to 4, and 
         n and m are allowed to be the same or different. 
       
     
     
         3 . The lubricating base oil of  claim 1 ,
 wherein Z +  is of formula (3):   
       
         
           
           
               
               
           
         
         n is 1 or 2; 
         X is methylene or oxygen; and 
         each R 1  and R 2  is independently an alkyl group having from 1 to 12 carbon atoms, optionally comprising an ether group, an ester group, a nitrile group and a silyl group. 
       
     
     
         4 . The lubricating base oil of  claim 1 , wherein the ionic liquid has a molecular weight of from 410 to 570. 
     
     
         5 . The lubricating base oil of  claim 1 , wherein the ionic liquid has a kinematic viscosity at of from 1 mm 2 /s to 100 mm 2 /s at 40 degrees C. 
     
     
         6 . The lubricating base oil of  claim 1 , wherein the ionic liquid has a pour point of at most zero degrees C. 
     
     
         7 . A lubricating oil composition comprising:
 the lubricating base oil of  claim 1 ; and   at least one selected from the group consisting of an antioxidant, an oiliness agent, an extreme pressure agent, a detergent dispersant, a viscosity index improver, a rust inhibitor, a metal deactivator and an antifoaming agent.   
     
     
         8 . A method of lubricating an object, the method comprising:
 contacting the lubricating oil composition of  claim 7  with an object in need thereof,   wherein the object is at least one selected from the group consisting of an oil-impregnated bearing, a fluid dynamic bearing, vacuum equipment, and semiconductor manufacturing equipment.   
     
     
         9 . The lubricating base oil of  claim 2 ,
 wherein n is an integer of from 1 to 2,   m is an integer of from 1 to 2, and   n and m are allowed to be the same or different.   
     
     
         10 . The lubricating base oil of  claim 3 , wherein the alkyl group further comprises at least one selected from the group consisting of an ether group, an ester group, a nitrile group, and a silyl group. 
     
     
         11 . The lubricating base oil of  claim 3 , wherein the alkyl group has from 1 to 6 carbon atoms. 
     
     
         12 . The lubricating base oil of  claim 3 , wherein the alkyl group has from 1 to 4 carbon atoms. 
     
     
         13 . The lubricating base oil of  claim 4 , wherein the ionic liquid has a molecular weight of from 410 to 470. 
     
     
         14 . The lubricating base oil of  claim 4 , wherein the ionic liquid has a molecular weight of from 420 to 440. 
     
     
         15 . The lubricating base oil of  claim 5 , wherein the ionic liquid has a kinematic viscosity of from 10 mm 2 /s to 70 mm 2 /s at 40 degrees C. 
     
     
         16 . The lubricating base oil of  claim 5 , wherein the ionic liquid has a kinematic viscosity of from 20 mm 2 /s to 40 mm 2 /s at 40 degrees C. 
     
     
         17 . The lubricating base oil of  claim 6 , wherein the ionic liquid has a pour point of at most −10 degrees C. 
     
     
         18 . The lubricating base oil of  claim 6 , wherein the ionic liquid has a pour point of at most −20 degrees C. 
     
     
         19 . The lubricating base oil of  claim 1 , wherein the ionic liquid has an acid value of at most 1 mgKOH/g. 
     
     
         20 . The lubricating base oil of  claim 1 , wherein the ionic liquid has a flash point of at least 200 degrees C.