LAUSR

The dihydroxylation of fatty methyl esters is of prime importance for the synthesis of surfactants and lubricants. The conversion of methyl oleate (MO) to 98% yield of methyl-9,10-dihydroxystearate (MDHS) was performed in the presence of H2O2 and H3PW12O40 catalyst in the absence of a phase transfer agent. The study of the effect of hydrogen peroxide concentration revealed that significant catalytic activity was only achieved for an optimal amount of H2O2. A mechanism for this reaction was proposed where hydrogen peroxide reacts with H3PW12O40 to produce peroxo-phosphotungstate anions, which directly dihydroxylate MO. The recyclability of the catalyst was also studied. To this aim, a recyclable form of the heteropolyacid was synthesized using Cs cations (Cs2.3H0.7PW12O40). This catalyst was recycled up to three cycles without significant loss in catalytic performances.