A new kind of heteropolyacid (HPA) ionic liquid [(CH3)3NCH2CH2OH]H2PW12O40 (ChH2PW) has been synthesized
using choline chloride and H3PW12O40 (HPW) as precursors. The catalyst exhibited a novel switchable
property based on temperature. The separation of the catalyst would be explored by simply decreasing reaction
temperature without appreciable loss. Excellent conversions (97%) for esterification have been obtained under
microwave-accelerated conditions.