Patent ID: 8889607

Claim:
A lubricating oil base oil, comprising a diester represented by the following formula (1): where: R 1 and R 2 each independently represent a 1-ethylpentyl group, an n-heptyl group, or an n-hexyl group; and when the diester in which both of R 1 and R 2 each represent an n-heptyl group or an n-hexyl group being a linear alkyl group is defined as A, the diester in which one of R 1 and R 2 represents a 1-ethylpentyl group being a branched alkyl group while the other one of R1 and R2 represents an n-heptyl group or an n-hexyl group being a linear alkyl group is defined as B, and the diester in which both of R 1 and R 2 each represent a 1-ethylpentyl group being a branched alkyl group is defined as C, a molar ratio A:B:C of the diesters falls within a range of 25 to 65:30 to 50:3 to 25.