Synthesis of Palm Acide Polyol Esters Catalyzed by Acidic Ionic Liquid

Five acidic ionic liquids were investigated to synthesize palm acide polyol esters,the results indicated triethylammonium sulfate offers best catalytic activity.Based on temperature-controlled characteristics of triethylammonium sulfate,we designed a novel method for preparation of palm acide polyol esters,in which the reaction under relatively high temperature combined with the separation of the ionic liquid under relatively low temperature.The optimal conditions to produce palm acide pentaerythritol esters were obtained,these include a 6∶1 of palm acide/pentaerythritol,5% of the ionic liquid,210 ℃ of the reaction temperature and 3.5 h of reaction time.Under corresponding optimal conditions,five palm acide pentaerythritol esters,which includes palm acide pentaerythritol ester,palm acide trimethylolpropane ester,palm acide dihydroxymethylneopentane ester,palm acide sorbitol ester and palm acide 1,3-butanediol ester,were synthesized in the laboratory,their conversions were 94.6%,94.5%,97.0%,98.5% and 99.2%,respectively.After the completion of reaction,the triethylammonium sulfate precipitates and separates from the system with decreasing the temperature.The ionic liquid obtained can be used to subsequent new synthesis of palm acide polyol ester.The physicochemical properties of five palm acide polyol esters were investigated,the results exhibited these are of excellent fluid and low temperature characteristics,their viscosity index and pour point were in the range of 184~388 and-23~-40 ℃ respectively,the data confirm palm acide polyol ester can be used as base oil of biodegradable lubricant.