过氧磷钨酸季铵盐催化合成环氧柏木烷

Synthesis of epoxycedrane catalyzed by quaternary ammonium peroxy phosphotungstate

以钨酸钠、磷酸、过氧化氢(H_2O_2)和十六烷基三甲基氯化铵为原料制备了过氧磷钨酸季铵盐催化剂。通过FT-IR、TG对催化剂进行了结构和热稳定性的表征。在H_2O_2为氧化剂,无溶剂条件下,采用过氧磷钨酸季铵盐催化α-柏木烯环氧化合成环氧柏木烷。考察了各反应条件对环氧化反应的影响。结果表明,在反应温度60 ℃,反应时间3.5 h,H_2O_2与α-柏木烯摩尔比为1∶2,催化剂过氧磷钨酸季铵盐用量3.0% (以H_2O_2质量计,下同),助剂Na_2HPO_4用量1.6%条件下,环氧柏木烷的收率为65.7%,α-柏木烯的转化率为90.1%,环氧产物选择性可达72.9%。

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.