Abstract: A 1-butyl-3-methylimidazolium dodecatungstophosphate ([bmim]3PW12O40) catalyst with high resistance to water was prepared from 1-butyl-3-methylimidazolium bromide ([bmim]Br) and dodecatungsto-phosphoricacid (H3PW12O40). The catalyst was characterized by means of Fourier transform infrared spectroscopy, thermogravimetry-differential scanning calorimetry, n-BuNH2 potentiometric titration, and elemental analysis. Its catalytic activity for esterification of ethanol and acetic acid to ethyl acetate was measured. The results showed that there were three crystal-water molecules in the [bmim]3PW12O40catalyst, and it preserved the primary Keggin structure and acid strength of H3PW12O40. The acid amount of the [bmim]3PW12O40catalyst was less than that of H3PW12O40. The [bmim]3PW12O40catalyst exhibited higher catalytic activity and reusability in the esterification of ethanol and acetic acid to ethyl acetate.

Key words: 1-butyl-3-methylimidazolium bromide, dodecatungstophosphoric acid, heteropolyacid, 1-butyl-3-methylimidazolium dodecatungstophosphate, ethanol, acetic acid, esterification, ethyl acetate