A lubricant ester having enhanced hydrolytic stability is disclosed. The ester is a mono or diester of 2-ethyl-2-butyl-1,3-propanediol or an alkoxylate thereof and at least one carboxylic acid having 5-10 carbon atoms. The invention in a further aspect refers to a refrigeration working fluid comprising said ester and at least one halocarbon refrigerant.
