| abstract |
The present invention has low viscosity, excellent low-temperature fluidity, and high viscosity index, so that it has good lubricity over a wide temperature range, has low volatility, has thermal oxidation stability, and has low fuel consumption. To provide a lubricating base oil for internal combustion engines which is excellent in lubrication and a lubricating oil composition for internal combustion engines containing the base oil. A neopentyldiol ethylene oxide adduct obtained by adding ethylene oxide to a diol having a neopentyl structure in a proportion of 1 to 4 mol, and a saturated aliphatic monocarboxylic acid having 4 to 12 carbon atoms are obtained. A lubricating base oil for internal combustion engines comprising the ester obtained, wherein the saturated aliphatic monocarboxylic acid contains a linear carboxylic acid in a proportion of 50 mol% or more, and the kinematic viscosity at 100 ° C. of the ester is A lubricating base oil for an internal combustion engine having a viscosity of 1 to 5 mm 2 / s, a viscosity index of 140 or more, and a total acid value of 0.5 mgKOH / g or less. [Selection diagram] None |