Study On The Synthesis And Properties Of Ester Basis Oil Matching HFC-134a Refrigerant

The usage of Refrigerant Fully Halogenated Chlorofluorocarbons was restricted because it destroyed the ozonosphere. And the using of HFC-134a which was the best substituent was restricted because of the problems, such as not matching Refrigerant. Therefore it was significant to study on the low cost and environmental refrigerant lubricant matching HFC-134a.This subject was consigned by the petrochemical company. The synthesise of the basis oil matching HFC-134a refrigerant was studied by using its existing raw materials of diglycol and adipic acid. In this paper, under contraposing the subject specific requirements and considering other factors, the ester oil was determined as the synthetic objective. Five synthesis methods were analysised, and three of them were selected to be studied. The ester compounds including di-ester,polyol ester and duplicate-ester were researched comprehensivly, and their relative optimization laboratory synthesis process was established. In this process, the effects of the types and its dosage of dehydrate reagent, the kinds and mass of catalyst, the ratio of materials and the time on the esterification yield were determined. The five refining processes to the crude product were contrasted. The product was characterized by chemical methods, IR, GC-MS and LC-MS.The results showed that two kinds of duplicate-ester were up to the mustard of the company, and the di-ester and polyol ester were also up to the mustard of the company except the viscosity. The low -temperature characteristics of the alcohol-duplicate-ester was outstanding, and the viscosity-temperature characteristics of the acid-duplicate-ester was outstanding. The process had two steps and the optimal reaction conditions of the alcohol- duplicate-ester were as follows, the mol ratio of reactants n(diglycol):n(adipic acid): n(isooctanoic acid)=1:0.5:0.95, the mass faction of dehydrate reagent w₁(toluene)=30% and w₁(toluene)=30%,the mass faction of catalyst w₁(tetrabutyl titanate)=2% and w₂(alumina)=8% ,reaction time t₁₊₂=2h+2h, the esterification yield up to 99.2%. The process of synthesis of the acid-duplicate-ester also had two steps, and the optimal reaction conditions were : the mol ratio of reactants n(adipic acid):n(diglyco):n(isooctanol) =1:0.53:0.94, the mass faction of dehydrate reagent w₁(toluene)=20% and w₁(toluene)=15%,the mass faction of catalyst w(aluminum chloride)=1% ,reaction time t₁₊₂=1h+1h, the esterification yield up to 99.4%. The refining process to the crude product was ideal by using alkaline alumina. The thermal stability, Oxidation Stability and the hydrolytic stability of the duplicate-ester were poorer than di-ester and polyol ester.