A heteropolyacid-based ionic liquid as a thermoregulated and environmentally friendly catalyst in esterification reaction under microwave assistance

• Easily synthesis of HPA ionic liquid catalyst [(CH3)3NCH2CH2OH]H2PW12O40.
• Thermoregulated catalyst could be used as a homogeneous catalyst.
• First example of a highly efficiency by the ChCl functionalized HPA catalyst.
• A new eco-friendly catalyst for esterterification and easily handling for reuse.

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.