A Brønsted–Lewis-surfactant-combined heteropolyacid as an environmental benign catalyst for esterification reaction

Abstract A Bronsted–Lewis-surfactant-combined heteropolyacid (HPA) catalyst (C 16 TA)H 4 TiPW 11 O 40 (C 16 TA = cetyltrimethyl ammonium) had been designed and used as a water-tolerantly heterogeneous catalyst in esterification of free fatty acid with a higher conversion (94.7%) and excellent efficiency (91.8% yield) due to its acidic properties and structures. This micellar polyoxometalate catalyst was stable during the reaction and can be recycled by a simple separation process.