磷钨杂多酸季铵盐催化环己烯氧化合成1，2-环氧环己烷

以环己烯为原料,H_2O_2为氧化剂,K_2HPO_4为添加剂,考察了磷钨杂多酸季铵盐相转移催化剂催化环己烯环氧化的反应性能。结果表明,当体系中无K_2HPO_4时,1,2-环氧环己烷的水解情况严重,加入适量的K_2HPO_4可有效抑制1,2-环氧环己烷的水解。较佳的环氧化反应条件为:n(催化剂):n(K_2HPO_4):n (H_2O_2):n(环己烯)=0.003:0.01:0.7:1,三氯甲烷为溶剂,反应温度50～60℃,反应时间90 min,1,2-环氧环己烷选择性98%、收率66.5%。

EPOXIDATION OF CYCLOHEXENE BY QUATERNARY AMMONIUM HETEROPOLYPHOSPHATOTUNGSTATE PHASE-TRANSFER CATALYST

The catalytic performance of a phase-transfer catalyst,quarternary ammonium hetero- polyphosphatotungstate,for cyclohexene epoxidatin was investigated using cyclohexene as raw mate- rial,aqueous hydrogen peroxide as oxidant and HPO_4~(2-) as additive.The product epoxycyclohexane was hydrolyzed easily in the absence of an additive.However,when a proper amount of K_2HPO_4 was added into the reaction mixture,the epoxycyclohexane hydrolysis could be inhibited efficiently.With chloroform as solvent,the optimum conditions for this reaction were:n(cyclohexene):n(H_2O_2): n(K_2HPO_4):n(catalyst)=1:0.7:0.01:0.003 in molar ratios,reaction temperature 50-60℃, reaction time 90 min.Under the optimum conditions,the selectivity and the yield of cyclohexene oxide was 98% and 66.50%,respectively.