The present invention provides a working fluid composition for a refrigerating machine containing: a refrigerating machine oil containing, as a base oil, a mixed ester of (A) a complex ester synthesized from a polyhydric alcohol such as neopentyl glycol, a polybasic acid having 6 to 12 carbon atoms, a monohydric alcohol having 4 to 18 carbon atoms and the like, and (B) a polyol ester synthesized from a polyhydric alcohol such as neopentyl glycol and a monocarboxylic fatty acid having 4 to 18 carbon atoms, in a mass ratio of (A) the complex ester/(B) the polyol ester of 5/95 to 95/5; and a refrigerant such as carbon dioxide.

Improved organic anti-wear additive compositions are disclosed containing certain citric acid esters, e.g., mixtures comprising citrate oligomers, and fatty acid alkanolamides. The combination exhibits excellent and synergistic anti-wear activity in lubricants. The compositions of the invention beneficially allow one to reduce amounts of zinc and phosphorus that are often used in lubricants, while boosting anti-wear performance and maintaining, and often enhancing, friction reduction properties.

The present techniques relate to facilitating conversion of biosourced triglycerides into fatty acid esters by combining the biosourced triglycerides with a carbonate ester in presence of an alcohol, under catalytic transesterification conditions. A reaction mixture can be heated to a reaction temperature to operate a transesterification of the biosourced triglyceride with the carbonate ester under catalysis of the alcohol thereby forming a single-phase composition comprising the fatty acid esters. The reaction mixture can have a molar ratio of the biosourced triglyceride over the carbonate ester between 1:0.1 and 1:20. Compositions comprising the produced single-phase composition, and optionally an additive, can be used as diesel, jet fuel or lubricant.