Epoxidation of 1-butene to 1,2-butene oxide by transition metal disubstituted P-W-Mo ternary heteropoly quaternary ammonium salts

摘要

A series of transitional metal disubstituted ternary heteropoly quaternary ammonium salts, [TPA](4)H-3[PW7Mo3M2O38(H2O)(2)] (M = Mn, Co, Ni, Cu), were prepared by the reaction of the anion PW6Mo3O34 (9-) and the corresponding salts of the transitional metal in water, characterized by FI-IR, UV-Vis, XRD and TGA spectra, and appied to the epoxidation of 1-butene to 1,2-butene oxide (BO). The influences of temperature, reaction time, H2O2 concentration and catalyst concentration on the epoxidation of 1-butene were studied in the acetonitrile/hydrogen peroxide catalytic system. The variation ranges of these parameters ensuring a high H2O2 conversion and high selectivity of BO were established. It can be observed that the catalytic activity decreases in the order PWMoMn > PWMoCo > PWMoNi > PWMoCu. The best conversion of H2O2 and selectivity toward BO were achieved under optimized conditions: reaction time = 2 h, reaction temperature = 50 A degrees C, H2O2 concentration = 0.5 mol/L and a catalyst concentration of 2.5 g/L. In particular, the catalyst PWMoMn is the most active one for epoxidation of 1-butene to BO (selectivity of BO up to 97.6 %).