Provided is a lubricant base stock, a lubricating oil including the lubricant base stock and a method for improving viscosity temperature performance or viscosity index of an engine or other mechanical component lubricated with the lubricating oil. The lubricant base stock includes one or more liquid crystals represented by the formula:

R1-(A).sub.m-Y(B).sub.nR2

wherein R1 and R2 are the same or different and are a substituted or unsubstituted, alkyl or alkoxy group having from 0 to 24 carbon atoms; A and B are the same or different and are a cycloaliphatic group or aromatic group, provided at least one of A and B is an aromatic group; Y is a covalent bond, CH2-CH2-, CHCH, CC, OCOO, COO, CO, CSO, CSS, CS, O, S, SO, SO2-, CH2O, OCH2O, NO, ONO2, COOH, OH, or CN; and m and n are independently 0, 1, 2 or 3. The lubricant base stock has a kinematic viscosity of 2 cSt to 28 cSt at 40 C., and 1 cSt to 12 cSt at 100 C.

A lubricating oil composition that hardly generates precipitation attributable to a molybdenum compound under the low temperature environment and is excellent in a friction-reducing effect under the low temperature environment is provided. The lubricating oil composition is one including (A) a lubricating base oil, (B) a molybdenum-based compound, (C) a metal-based detergent, and (D) an ester compound having one or more hydroxyl groups in a molecule thereof, wherein the metal-based detergent (C) includes (C1) a calcium detergent and (C2) a magnesium detergent, and a content of the ester compound (D) having one or more hydroxyl groups in a molecule thereof is 0.03 to 1.20 mass % on a basis of the total amount of the lubricating oil composition.

A lubricating oil composition that hardly generates precipitation attributable to a molybdenum compound under the low temperature environment and is excellent in a friction-reducing effect under the low temperature environment is provided. The lubricating oil composition is one including (A) a lubricating base oil, (B) a molybdenum-based compound, (C) a metal-based detergent, and (D) an ester compound having one or more hydroxyl groups in a molecule thereof, wherein the metal-based detergent (C) includes (C1) a calcium detergent and (C2) a magnesium detergent, and a content of the ester compound (D) having one or more hydroxyl groups in a molecule thereof is 0.03 to 1.20 mass % on a basis of the total amount of the lubricating oil composition.

The invention provides a grease composition containing a base oil, a thickener, and an anti-flaking additive such as a compound represented by, for example, formula (1-1), which grease composition can prevent the white layer flaking of the rolling bearings. (In the formula, R1 and R4 are each independently a straight-chain or branched alkyl or alkenyl group having 1 to 20 carbon atoms.) ##STR00001##

Compounds having the formula (F-I) below are provided herein:

##STR00001##

wherein: R.sup.1 is a C.sub.1-C.sub.5000 alkyl group; R.sup.2 is (i) a C.sub.4-C.sub.30 linear alkyl group or (ii) a C.sub.4-C.sub.5000 branched alkyl having the formula (F-II) below:

##STR00002##

wherein R.sup.5 and R.sup.6 at each occurrence are each independently a hydrogen or a C.sub.1-C.sub.30 linear alkyl group and n is a positive integer, provided however, among all of R.sup.5 and R.sup.6, at least one is a C.sub.1-C.sub.30 linear alkyl group; and R.sup.7 is a hydrogen or a C.sub.1-C.sub.30 linear alkyl group; R.sup.3 is hydrogen or a C.sub.1-C.sub.5000 alkyl group; and R.sup.4 is a C.sub.1-C.sub.50 alkyl group or an aromatic group. Processes for preparing compounds of formula (F-I) as well as base stock and lubricant compositions containing compounds of formula (F-I) are also provided.

Provided are a lubricating oil composition for internal combustion engine capable of preventing a deterioration of the combustion state of a spark-ignition internal combustion engine, specifically, a lubricating oil composition to be used for a spark-ignition internal combustion engine in which a total tension per piston of tensions applied to the piston ring is 100 N or less, the lubricating oil composition being a lubricating oil composition including a base oil, (A) a calcium-based detergent, at least one selected from (B1) a sodium-based additive and (B2) a magnesium-based additive, and (C) an ash-free sulfur-based additive in predetermined contents; a method for producing the lubricating oil composition; a spark-ignition internal combustion engine using the lubricating oil composition; and a method for lubricating the internal combustion engine.

The refrigerator lubricating oil of the present invention contains: a base oil containing, as a major component, a polyol ester (A) of a fatty acid (a1) that is a fatty acid having a number of carbon atoms of from 3 to 18 and a polyol (a2) that is selected from neopentyl glycol, trimethylolethane, trimethylolpropane, trimethylolbutane, pentaerythritol, and dipentaerythritol; and a disulfide and/or trisulfide compound (B), and the disulfide and/or trisulfide compound (B) is blended in an amount of from 30 to 10,000 ppm by mass in terms of sulfur equivalent based on the total amount of the refrigerator lubricating oil.

A synergistic mixture comprising from 1 to 99.9% by weight of compounds having structural elements (I) ##STR00001##
in which the free valencies on the oxygen atom and on the nitrogen atom may be combined to form a five-, six- or seven-membered ring and the benzene ring may also bear substituents at one or more of the free positions, and from 0.1 to 99% by weight of sulfur-containing organic compounds with antioxidant action. This synergistic mixture is suitable as a stabilizer for stabilizing inanimate organic material, especially mineral oil products and fuels, against the action of light, oxygen and heat.

A synergistic mixture comprising from 1 to 99.9% by weight of compounds having structural elements (I) ##STR00001##
in which the free valencies on the oxygen atom and on the nitrogen atom may be combined to form a five-, six- or seven-membered ring and the benzene ring may also bear substituents at one or more of the free positions, and from 0.1 to 99% by weight of sulfur-containing organic compounds with antioxidant action. This synergistic mixture is suitable as a stabilizer for stabilizing inanimate organic material, especially mineral oil products and fuels, against the action of light, oxygen and heat.

A constant velocity joint having a boot constructed from a thermoplastic polyether ester as the boot material. The boot includes a lubricating grease composition for lubricating the constant velocity joint, the lubricating grease composition comprising calcium lignin sulfonate.