NEW MATERIAL:A higher carboxylic acid triester of adamantanetriol expressed by formula I (Z is H or OH; R1-R3 are 4-30C alkyl or cycloalkyl).

EXAMPLE: Caprylic acid triester of adamantane-1,3,5-triol.

USE: Used for high-performance synthetic lubricating oil. Useful as engine oil, gear oil, hydraulic oil, grease, vacuum pump oil, bearing impregnating oil or gas turbine oil, etc., as having excellent heat stability and respectively excellent low-temperature properties and high-temperature properties such as high kinematic viscosity at high-temperature in spite of low pour point.

PREPARATION: 1mol of adamantane-1,3,5-triol expressed by formula II and 3-6mol of higher carboxylic acid expressed by the formula R-COOH or reactive derivative of said acid are subjected to esterification reaction at 50-150°C to obtain the compound expressed by formula I for the case of Z is H.