硒钼杂多配合物及其稀土盐的合成及催化苯酚羟化反应的研究

Preparation of Heteropoly Molybdoselenite Complex, Its Lanthanide Salts and Their Catalysis for Hydroxylation of Phenol

合成了杂多配合物(NH4)6[Se2Mo8O31]·5H2O,在此基础上合成了其稀土盐Ln2[Se2Mo8O31]·xH2O(Ln=La3+,Ce3+,Nd3+,Sm3+),探讨了这些杂多配合物在苯酚羟化反应中的催化作用,发现稀土盐的催化效果低于配合物(NH4)6[Se2Mo8O31]·5H2O的催化效果;在溶剂丙酮中苯酚的转化率大于在乙腈中的转化率。通过正交法研究了反应温度、原料比、反应时间和催化剂用量对苯酚转化率、产品分布和过氧化有效转化率的影响,找到了最佳反应条件,即在苯酚/H2O2(摩尔比)为1,催化剂用量10g·mol-1,反应温度70℃,反应时间4h时,得到苯酚转化率29.65%,产品选择率77.2%。

A heteropoly molybdoselenite complex （NH4）6[Se2Mo8O31]·5H2O and its lanthanide salts Ln2[Se2Mo8O31]·xH2O （Ln=La^3＋,Ce^3＋,Nd^3＋,Sm^3＋） were synthesized and characterized with elemental analysis, IR, UV, XRD and TG-DTA. Their reactivity for hydroxylation of phenol was investigated. The results show that catalytic activity of （NH4）6[Se2Mo8O31]·5H2O is higher than that of its lanthanide salts. The reaction temperatures, the reaction time, the catalyst amount, the ratio of phenol and H2O2 influence on the phenol conversation, H2O2 selectivity and product distribution. The optimum reaction condition was obtained with orthogonal method. At optimum reaction condition which the ratio of phenol and H2O2 = 1 ： 1, reaction time is 4 h, reaction temperatures is 70℃ and catalyst is 10 g· mol^-1, the conversation of phenol reaches as high as 29.65%, the product selectivity can reach 77.2% for catalyst （NH4）6[Se2Mo8O31]·5H2O.