Abstract An ester condensation product of (1) a perfluoro-tertiary-alkyl alcohol in which the perfluoro-alkyl group has not more than 20 carbon atoms, is directly bonded to the alcoholic hydroxyl radical, and has at least one perfluoro-methyl group bonded to the tertiary carbon atom, and (2) an organic acid of not more than 18 carbon atoms with at most double bond unsaturation and selected from the group consisting of a hydrocarbon carboxylic acid, a hydrocarbon sulphonic acid, a hydrocarbon phosphonic acid, a hydrocarbon silicic acid or cyanuric acid, or a halogen substituted counterpart thereof. Illustrative uses of these esters include inert heat exchange fluids, as polymerizable monomers, textile treatment, surface active agents, and the like.