Influence of structural differences and acidic properties of phosphotungstic acids on their catalytic performance for acylation of pyruvate ester to α-acyloxyacrylate ester

Abstract Various heteropolyacids, including Keggin-type (H 3 PW 12 O 40 ), Dawson-type (H 6 P 2 W 18 O 62 ) and Preyssler-type (H 14 [NaP 5 W 30 O 110 ]) phosphotungstic acids, were examined as catalysts for acylation of ethyl pyruvate with acetic anhydride to synthesize ethyl α-acetoxyacrylate in liquid phase. This compound is one of candidate monomers for bio-based polymers bearing high thermal durability and transparency. Catalytic performances correlated to the acid strength, the proton number and the stability of the phosphotungstic acids. Notably, performance of Preyssler-type phosphotungstic acid per unit mole of catalyst was higher than that of Keggin-type.