以自制的两种Keggin型杂多酸,硅钼钒杂多酸和硅钨钒杂多酸作催化剂,冰醋酸作溶剂,过氧化氢作氧化剂,研究了由苯直接羟基化制苯酚的催化活性,发现对于所研究的体系,即苯为0.02mol,过氧化氢为0.16mol,冰醋酸为0.24mol,当杂多酸的用量为0.10—0.15mmol、反应温度323K、反应时间80min时,硅钼钒和硅钨钒上苯酚的收率分别可达17.2%和4.3%,选择性达90.3%和87.4%.
The catalytic performance of two Keggin-type heteropolyacids for the direct hydroxylation of benzene to phenol was studied. Glacial acetic acid was employed as the solvent, while hydrogen peroxide was used as the oxidant. It was found that in the system composed of 0.02 tool benzene, 0. 16 tool hydrogen peroxide and 0.24 tool glacial acetic, when 0. 10 - 0.15 mmol of heteropolyacids were used and keeping the reaction temperature at 323K for 80 - 100 rain, the yields of phenol over silicon-substituted heteropolymolybdates and heteropolytungstates could reach 17.2% and 4.3%, with the selectivities of 90.3% and 87.2%, respectively.