Abstract: The invention concerns refrigerant compositions which comprise a hydrofluorocarbon based refrigerant and, mixed with the refrigerant, a polyol ester based lubricant. According to the invention the polyol ester comprises a diol having a strongly sterically hindered hydrogen attached to the carbon in position 2, said diol being esterified with a mixture of mono- and diabasic carboxylic acids. In particular the diol is 2-ethyl-1,3-hexanediol or 1,4-dimethylol-cyclohexane. The complex esters in refrigerant mixtures have good lubricant properties and good solubility in HFC compounds.

Abstract: The invention concerns a refrigerant composition which comprises a chlorine-free hydrofluorocarbon based refrigerant and, mixed with the refrigerant, a lubricant comprising a polyol ester. According to the invention the polyol ester comprises an ester of 2-butyl-2-ethyl-1,3-propane diol, the carboxylic acid residue of which is derived from a linear or branched C4 . . . C8-carboxylic acid or an anhydride thereof, or it is derived from a mixture of linear or branched C4 . . . C18-carboxylic acids or anhydrides thereof. The present invention also concerns novel complex esters of 2-butyl-2-ethyl-1,3-propanediol, which contain residues of mono- or bivalent carboxylic acids. The novel esters exhibit good solubility in fluorinated hydrocarbons and excellent lubricating properties.

Abstract: The invention concerns refrigerant compositions which comprise a hydrofluorocarbon based refrigerant and, mixed with the refrigerant, a polyol ester based lubricant. According to the invention the polyol ester comprises a diol having a strongly sterically hindered hydrogen attached to the carbon in position 2, said diol esterified with a mixture of mono- and diabasic carboxylic acids. In particular the diol is 2-ethyl-1,3-hexanediol or 1,4-dimethylol-cyclohexane. The complex esters in refrigerant mixtures have good lubricant properties and good solubility in HFC compounds.