改性多金属氧簇应用于环己醇选择性催化氧化制取环己酮

以柠檬酸为络合剂，采用溶胶-凝胶法制备了多金属氧簇K9[Sb1.0W9O33]，再用十六烷基三甲基溴化铵（CTAB）对其改性，得到改性多金属氧簇(CTAB)9[Sb1.0W9O33]；以过氧化氢氧化环己醇制取环己酮为探针反应，考察了催化剂制备过程中n(Sb)∶n(W)以及n(过氧化氢)∶n(环己醇)、n((CTAB)9[Sb1.0W9O33])∶n (环己醇+过氧化氢)、反应温度、反应时间等反应条件对氧化反应的影响。实验结果表明，当n(Sb)∶n(W)=1.0∶9时制得的(CTAB)9[Sb1.0W9O33]催化剂活性最高；氧化反应的适宜条件为：n(过氧化氢)∶n(环己醇)=1.5、n((CTAB)9[Sb1.0W9O33])∶n (环己醇+过氧化氢)=0.001 2、反应温度353 K、反应时间2.0 h；在此条件下，环己醇转化率为97.4%，环己酮选择性为99.7%。催化剂经XRD表征，揭示了(CTAB)9[Sb1.0W9O33]的微观结构和内在规律性，搀杂少量CTAB，[Sb1.0W9O33]9-保持原来的基本结构，[Sb1.0W9O33]9-与CTAB+之间存在协同效应，有效提高了环己酮的选择性。

Selective Catalytic Oxidation of Cyclohexanol to Cyclohexanone Over Modified Polyoxomeatalate Catalysts

K9[Sb1.0W9O33] was prepared by sol-gel method with citric acid as complexing agent,which was modified with cetyltrimethylammonium bromide(CTAB) to obtain(CTAB)9[Sb1.0W9O33].Catalytic oxidation cyclohexanol to cyclohexanone by H2O2 over(CTAB)9[Sb1.0W9O33] was used as a probe reaction to investigate the effects of atomic ratio n(Sb)/n(W) in preparation of catalyst,the reaction conditions of n(H2O2)/n(Cyclohexanol),n((CTAB)9[Sb1.0W9O33])/n(Cyclohexanol+H2O2),reaction temperature(T),reaction time(t).The results showed that the optimum conditions were n(Sb)/n(W)=0.11,n(H2O2)/n(Cyclohexanol)=1.5,n((CTAB)9[Sb1.0W9O33])/n(Cyclohexanol+H2O2)=0.0012,T= 353 K,t=2.0 h,under which the conversion of cyclohexanol reached 97.4%,selectivity to cyclohexanone reached 99.7%.(CTAB)9[Sb1.0W9O33] was detected by means of XRD,and its micro-structure and essence disciplinarian of were disclosed.[Sb1.0W9O33]9-still maintained its original structure,possessing a cooperative effect with CTAB+ during the oxidation of cyclohexanol,resulting in the selectivity to cyclohexanone enhanced effectively.