Ionic Liquid, Lubricant, and Magnetic Recording Medium

Abstract

A lubricant, which includes an ionic liquid including a conjugate base and a conjugate acid, wherein the conjugate acid has a group including a straight-chain hydrocarbon group having 6 or more carbon atoms, a pKa of an acid that is a source of the conjugate base in acetonitrile is 10 or less, and solubility of the ionic liquid to CF 3 (CHF) 2 CF 2 CF 3 is 0.1 parts by mass relative to 100 parts by mass of CF 3 (CHF) 2 CF 2 CF 3 .

1 . A lubricant comprising:
 an ionic liquid including a conjugate base and a conjugate acid,   wherein the conjugate acid has a group including a straight-chain hydrocarbon group having 6 or more carbon atoms,   a pKa of an acid that is a source of the conjugate base in acetonitrile is 10 or less, and   solubility of the ionic liquid to CF 3 (CHF) 2 CF 2 CF 3  is 0.1 parts by mass or greater relative to 100 parts by mass of CF 3 (CHF) 2 CF 2 CF 3 .   
     
     
         2 . The lubricant according to  claim 1 ,
 wherein the conjugate acid is represented by General Formula (A) below, General Formula (B) below, General Formula (C) below, General Formula (D) below, General Formula (E) below, or General Formula (F) below,   
       
         
           
           
               
               
           
         
         where, in General Formula (A), R 1  is a group including a straight-chain hydrocarbon group having 6 or more carbon atoms, and R 2  is a hydrogen atom or a hydrocarbon group, 
         in General Formula (B), R 1  is a group including a straight-chain hydrocarbon group having 6 or more carbon atoms, 
         in General Formula (C), R 1  is a group including a straight-chain hydrocarbon group having 6 or more carbon atoms, 
         in General Formula (D), R 1  is a group including a straight-chain hydrocarbon group having 6 or more carbon atoms, and R 2  is a hydrogen atom or a hydrocarbon group, 
         in General Formula (E), R 3  is a hydrocarbon group, R 4  is a hydrogen atom or a hydrocarbon group, and R 5  is a group including a C8 or higher fluorinated hydrocarbon group including fluorinated hydrocarbon having 4 or more carbon atoms, and 
         in General Formula (F), R 1  is a group including a straight-chain hydrocarbon group having 6 or more carbon atoms, and n is an integer of 1 or greater but 3 or less. 
       
     
     
         3 . The lubricant according to  claim 1 ,
 wherein the conjugate base is represented by General Formula (X) below, General Formula (Y) below, or General Formula (Z) below,   
       
         
           
           
               
               
           
         
         where, in General Formula (X), l is an integer of 1 or greater but 12 or less, 
         in General Formula (Y), n is an integer of 1 or greater but 12 or less, and 
         in General Formula (Z), n is an integer of 0 or greater but 6 or less. 
       
     
     
         4 . A magnetic recording medium comprising:
 a non-magnetic support;   a magnetic layer disposed on the non-magnetic support; and   the lubricant according to  claim 1 , disposed on the magnetic layer.   
     
     
         5 . An ionic liquid comprising:
 a conjugate base; and   a conjugate acid,   wherein the conjugate acid has a group including a straight-chain hydrocarbon group having 6 or more carbon atoms,   a pKa of an acid that is a source of the conjugate base in acetonitrile is 10 or less, and   solubility of the ionic liquid to CF 3 (CHF) 2 CF 2 CF 3  is 0.1 parts by mass or greater relative to 100 parts by mass of CF 3 (CHF) 2 CF 2 CF 3 .   
     
     
         6 . The ionic liquid according to  claim 5 ,
 wherein the conjugate acid is represented by General Formula (A) below, General Formula (B) below, General Formula (C) below, General Formula (D) below, General Formula (E) below, or General Formula (F) below,   
       
         
           
           
               
               
           
         
         where, in General Formula (A), R 1  is a group including a straight-chain hydrocarbon group having 6 or more carbon atoms, and R 2  is a hydrogen atom or a hydrocarbon group, 
         in General Formula (B), R 1  is a group including a straight-chain hydrocarbon group having 6 or more carbon atoms, 
         in General Formula (C), R 1  is a group including a straight-chain hydrocarbon group having 6 or more carbon atoms, 
         in General Formula (D), R 1  is a group including a straight-chain hydrocarbon group having 6 or more carbon atoms, and R 2  is a hydrogen atom or a hydrocarbon group, 
         in General Formula (E), R 3  is a hydrocarbon group, R 4  is a hydrogen atom or a hydrocarbon group, R 5  is a group including C8 or higher fluorinated hydrocarbon group including fluorinated hydrocarbon having 4 or more carbon atoms, and 
         in General Formula (F), R 1  is a group including a straight-chain hydrocarbon group having 6 or more carbon atoms, and n is an integer of 1 or greater but 3 or less. 
       
     
     
         7 . The ionic liquid according to  claim 5 ,
 wherein the conjugate base is represented by General Formula (X) below, General Formula (Y) below, or General Formula (Z) below,   
       
         
           
           
               
               
           
         
         where, in General Formula (X), l is an integer of 1 or greater but 12 or less, 
         in General Formula (Y), n is an integer of 1 or greater but 12 or less, and 
         in General Formula (Z), n is an integer of 0 or greater but 6 or less.