| abstract |
This lubricant contains a protic ionic liquid having a conjugate acid (B + ) and a conjugate base (X - ), the ionic liquid is represented by general formula (1), and the conjugate base is one of the conjugate base of sulfonic acid, the conjugate base of sulfonimide, or the conjugate base of trisulfonylmethide. Here, in general formula (1), R 1 and R 2 are hydrogen atoms, or R 1 and R 2 form a benzene ring together with the carbon atoms to which each is bonded, R 3 represents a straight-chain hydrocarbon group having at least 10 carbon atoms, and R 4 represents a hydrogen atom or a hydrocarbon group. |