To provide a composition for a heat cycle system, which comprises a working fluid for heat cycle which has a low global warming potential and high stability, and which can replace R410A, and a heat cycle system employing the composition. A composition for a heat cycle system, which comprises a working fluid for heat cycle containing trifluoroethylene, and a stabilizer for preventing deterioration of the working fluid for heat cycle, such as an oxidation resistance-improving agent, a heat resistance-improving agent or a metal deactivator, and a heat cycle system employing the composition for a heat cycle system.

To provide a composition for a heat cycle system, which comprises a working fluid for heat cycle which has a low global warming potential and high stability, and which can replace R410A, and a heat cycle system employing the composition. A composition for a heat cycle system, which comprises a working fluid for heat cycle containing trifluoroethylene, and a stabilizer for preventing deterioration of the working fluid for heat cycle, such as an oxidation resistance-improving agent, a heat resistance-improving agent or a metal deactivator, and a heat cycle system employing the composition for a heat cycle system.

A composition that includes one or more compounds represented by the formula

##STR00001##

wherein R1 and R2 are same or different and are the residue of an alkyl group having more than 10 carbon atoms wherein the composition has a viscosity (Kv.sub.100) from 2 to 300 at 100 C. as determined by ASTM D-445, and a viscosity index (VI) from 100 to 300 as determined by ASTM D-2270. The disclosure also relates to a process for producing the composition, a lubricating oil base stock and lubricating oil containing the composition, and a method for improving oxidative stability of a lubricating oil by using as the lubricating oil a formulated oil containing the composition.

(1) A cylinder lubricating oil composition for a crosshead diesel engine, the composition having a sulfated ash content of 2.0 to 5.5 mass %; a base number of 15 to 45 mgKOH/g; and an autoignition temperature of no less than 262? C. (2) A cylinder lubricating oil composition for a crosshead diesel engine, comprising: a lubricant base oil; (B) a Ca sulfonate detergent having a base number of no less than 10 mgKOH/g and less than 60 mgKOH/g; (C) a Ca phenate detergent having a base number of 55 to 200 mgKOH/g; (D) an amine antioxidant; and (E) a zinc dithiophosphate, wherein the composition has a base number of no less than 15 mgKOH/g and less than 120 mgKOH/g.

There are provided a composition for a heat cycle system containing a working medium for heat cycle that has a low global warming potential and high stability, which can be used as a substitute for HFC-134a and HFC-245fa, and a heat cycle system using this composition. The composition for a heat cycle system contains: a working medium for heat cycle containing 1-chloro-2,3,3,3-tetrafluoropropene; and a stabilizer suppressing deterioration of the working medium for heat cycle such as an oxidation resistance improver, a heat resistance improver, or a metal deactivator, and the heat cycle system uses this composition for a heat cycle system.

Disclosed is a lubricating oil composition comprising an oil of lubricating viscosity and an oil soluble synergistic mixture of antioxidants, said mixture comprising: a) a hindered amine antioxidant according to formula (I) ##STR00001## wherein each R.sup.1 is independently selected from a substituted or unsubstituted, branched or linear, C.sub.1-C.sub.20 hydrocarbyl group; R.sup.2 is selected from the group consisting of a hydrogen atom or a, substituted or unsubstituted, branched or linear, C.sub.1-C.sub.20 hydrocarbyl group; each R.sup.3 is independently selected from the group consisting of a hydrogen atom or a, substituted or unsubstituted, branched or linear, C.sub.1-C.sub.20 hydrocarbyl group; each R.sup.4 is independently selected from the group consisting of a hydrogen atom or a, substituted or unsubstituted, branched or linear, C.sub.1-C.sub.20 hydrocarbyl group; n is an integer from 1 to 4; and m is an integer from 1 to 5; and b) a molybdenum succinimide complex.

A fluid contains a base oil consisting of an alcohol-initiated polyalkylene glycol where polyalkylene glycol component is selected from a homopolymer of 1,2-butylene oxide and copolymer of 1,2-butylene oxide and propylene oxide; a glycerol-initiated unsaturated ester that is free of tertiary carbon atoms and quaternary carbon atoms; and an antioxidant.

A fluid contains a base oil and an antioxidant, the base oil consisting of sulfur-containing polyalkylene glycol where greater than 80 weight-percent of the fluid is a sulfur-containing polyalkylene glycol and less than one weight-percent of the fluid is water, with weight percent based on total fluid weight an wherein the sulfur-containing polyalkylene glycol is free of oxygen bound directly to sulfur.

Disclosed herein is a mixed composition for a refrigerator, the mixed composition containing: a refrigerant containing at least one unsaturated fluorinated hydrocarbon compound selected from compounds represented by the following molecular formula (1): C.sub.pF.sub.rH.sub.s (1), provided that the compound has one or more carbon-carbon unsaturated bond in a molecule: and a refrigerator lubricating oil containing, as a major component, a polyoxyalkylene glycol compound represented by the following general formula (2), and containing a phenothiazine compound in an amount of 1.0% by mass or more based on the total amount of the refrigerator lubricating oil: R.sup.1[(OR.sup.2).sub.mOR.sup.3].sub.n (2). A mixed composition for a refrigerator is provided having a lower possibility of autoignition in a high temperature environment even during unexpected leakage in a refrigerator using a refrigerant containing a slightly flammable refrigerant. A refrigerator lubricating oil is provided that is capable of being applied to the mixed composition.

There are provided a composition for a heat cycle system containing a working medium for heat cycle that has a low global warming potential and high stability, which can be used as a substitute for HFC-134a and HFC-245fa, and a heat cycle system using this composition. The composition for a heat cycle system contains: a working medium for heat cycle containing 1-chloro-2,3,3,3-tetrafluoropropene; and a stabilizer suppressing deterioration of the working medium for heat cycle such as an oxidation resistance improver, a heat resistance improver, or a metal deactivator, and the heat cycle system uses this composition for a heat cycle system.