Abstract:

A catalyst, namely quaternary ammonium peroxy phosphotungstate, was prepared using sodium tungstate, phosphoric acid, hydrogen peroxide and cetyltrimethylammonium chloride. The structure and thermal stability of the catalyst were characterized by infrared spectroscopy （FT-IR） and thermogravimetric analysis （TG）. The synthesized catalyst was used in the epoxidation of α-cedrene using H₂O₂ as oxidant and without any solvent. The effects of reaction conditions on the epoxidation were studied. The optimized reaction conditions were obtained as follows: the reaction temperature was 60 ℃; the reaction time was 3.5 h; the molar ratio of raw materials was n（H₂O₂）∶n（α-cedrene）=1∶2; the catalyst and cocatalyst （Na₂HPO₄） were added in the amounts corresponding to 3.0% and 1.6% of H₂O₂, respectively. Meanwhile, the yield of epoxycedrane, the conversion of α-cedrene and the epoxy-product selectivity were 65.7%, 90.1% and 72.9%, respectively.

Key words: epoxycedrane, phosphotungstate, α-cedrene;