Abstract:

A catalyst, namely quaternary ammonium phosphotungstate, was prepared by using phosphotungstic acid, H₂O₂ and cetyltrimethylammonium chloride as raw materials. Then, activated carbon was used to support the catalyst to form an activated carbon-supported phosphotungstic acid quaternary ammonium salt catalyst. The structure of the catalyst was characterized by FT-IR, XRD and SEM. It was used as a catalyst for the synthesis of thujopsanone. The effects of reaction conditions on the oxidation were studied. The optimized reaction was obtained under the conditions as follows: quaternary ammonium phosphotungstate loading was 30%; the reaction temperature was 70 ℃; the molar ratio of raw materals was n（H₂O₂）∶n（thujopsene） of 1.8∶1; the reaction time was 6 h; the catalyst was added in the amount corresponding to 8% of thujopsene. Meanwhile, the yield of thujopsanone, the conversion of thujopsene and the selectivity to thujopsanone were 65.7%, 90.9% and 72.3%, respectively, and the catalyst could be recycled for three times.

Key words: thujopsanone, activated carbon supported quaternary ammonium phosphotungstate, thujopsene, essence