LUBRICANT COMPOSITION USED FOR COMPRESSING AMMONIA REFRIGERANT AND METHOD FOR LUBRICATING COMPRESSOR FOR AMMONIA REFRIGERANT

摘要

PROBLEM TO BE SOLVED: To obtain a lubricant compsn. having a specified viscosity and an excellent compatibility with an ammonia refrigerant by using, as the base oil, a cyclic compd. represented by a specific formula having dioxolane or dioxane rings. SOLUTION: Sorbitol is reacted with a carbonyl compd. (e.g. methyl ethyl ketone) in the presence of an acid catalyst (e.g. p-toluenesulfonic acid) to give a cyclic compd. represented by the formula (wherein R<11> to R<16> are each 1-8C alkyl) having dioxolane or dioxane rings and a hydroxyl value of about 2mgKOH/g or lower. The cyclic compd. as the base oil is compound with about 0.1-1.0wt.% amine antioxidant (e.g. p,p'-dioctyldiphenylamine) to give a lubricant compsn. having a viscosity at 40 deg.C of 8-220mm<2> /s. About 0.1-2wt.% this compsn. is dissolved in an ammonia refrigerant to be used desirably.