The esterification of oleic acid was applied in order to screen the suitability a series phosphotungstic-based Wells-Dawson types compounds as potential catalysts heterogeneous transesterification sunflower waste cooking oil. This test reaction indicated that phosphotungstic heteropolyacid H6P2W18O62·xH2O, dispersed on titania oxide loading 15 mg per m2 support (named 42% HPA/TiO2) and possessi...

Six quaternary phosphonium salts (QPSs) in combination with phosphotungstic heteropolyacid, H3PW12O40, were tested the epoxidation of rapeseed oil fatty acid methyl esters a hydrogen peroxide aqueous solution. The QPSs consisted trihexyl(tetradecyl)phosphonium [P6], tributyl-tetradecylphosphonium [P4] or tetraoctylphosphonium [P8] cation and different anions—chloride (Cl−), bromide (Br−), tetra...