A lubricant base oil of the present invention includes an ester compound including: a structural moiety (A) that is derived from an alcohol compound (A); and a structural moiety (B) that is derived from a carboxylic acid, the structural moiety B including: a structural moiety (B1) that is derived from a monocarboxylic acid (B1); and a structural moiety (B2) that is derived from an aliphatic monocarboxylic acid (B2) having 4 or more and 18 or less carbon atoms. According to the present invention, it is possible to provide a lubricant base oil having excellent low-temperature stability and high heat resistance while maintaining torque-lowering properties.

A fluorine-containing ether compound represented by Formula (1) is provided.
R.sup.1OR.sup.2CH.sub.2R.sup.3CH.sub.2R.sup.4R.sup.5(1)
(in the formula, R.sup.3 is a perfluoropolyether chain; R.sup.1 is an alkenyl group having 2 to 8 carbon atoms or an alkynyl group having 3 to 8 carbon atoms; R.sup.2 and R.sup.4 are each independently a divalent linking group having one or more hydroxyl groups; and R.sup.5 is a group represented by Formula (2) shown below.)
O(CH.sub.2).sub.gNR.sup.6R.sup.7(2)
(in the formula, g is an integer of 2 or 3; R.sup.6 and R.sup.7 are the same or different saturated aliphatic groups; and R.sup.6 and R.sup.7 may form a ring structure together with a nitrogen atom.)

A lubricant provides enhanced performance at high temperatures, along with a higher evaporation temperature, where the main-chain includes a moiety with a rotational energy barrier that is higher than CF.sub.2. The lubricant has the general Formula (I): ##STR00001##
wherein Rc is a multivalent central group, Rb is a main chain group having a constituent with a higher rotational energy threshold than CF.sub.2, Re is an end group having at least one anchoring functional group, m is from 2 to 50, and n is from 2 to 8. The constituent with a higher rotational energy threshold than CF.sub.2, may be a substituted or non-substituted aromatic group.

One aspect of the present invention relates to a dinaphthyl ether compound represented by formula (1): ##STR00001##
in the formula (1), R.sup.1 and R.sup.2 are the same or different and each represent a linear or branched hydrocarbon group having 6 to 32 carbon atoms; m and n are each a real number of 0 or more and satisfy 1.0m+n3.0.