Study on esterification of highly efficient ionic liquid catalyst

Four water-stable ionic liquids were synthesized and showed good catalytic activity in esterification of oleic acid to ethyl oleate.Under esterification conditions:n(ethanol) ∶n(oleic acid)=6 ∶1,temperature 77 ℃ and time 6 h,mass percentage of catalyst relative to oleic acid 8%,the ionic liquid 1-ethyl-pyridinium hydrosulfate showed the best catalytic activity and the yield of ethyl oleate could reach 95.9%.During the esterification of fatty acid to fatty acid methyl ester,the four ionic liquids showed good activities,and the yields of fatty acid methyl ester were all above 94%.The ionic liquids were stable and could be reused.