Keggin型多元杂多化合物催化氧化苯甲醇制苯甲醛

合成了一系列具有Keggin结构的P-V-Mo-W四元杂多化合物(Cpyr)3+xPVxMoyW12-x-yO40·nH2O其中,Cpyr=(C16H32C5H4N)+,x=0、1、2和3],采用傅里叶变换红外光谱和X射线衍射等方法表征了杂多化合物的结构;以磷钒钼钨杂多化合物为相转移催化剂,用m(H2O2)=30%双氧水氧化苯甲醇制备苯甲醛。考察了催化剂的种类、溶剂的类型和反应条件(催化剂用量、反应温度、反应时间、H2O2用量)对苯甲醇氧化反应的影响。在优化条件下,即苯甲醇0.1mol、催化剂(Cpyr)5PV2Mo5W5O400.04mmol、m(H2O2)=30%H2O20.1mol、在100℃反应8h、溶剂水10mL,苯甲醇的转化率达88.51%、苯甲醛的选择性达96.06%。

Oxidation of benzyl alcohol to benzaldehyde over Keggin type multicomponent heteropoly compounds

Multicomponent heteropoly compounds (Cpyr)_(3+x)PV_xMo_yW_(12-x-y)O_(40)·nH_2O with Keggin structure were synthesized and proved by FTIR and X-ray spectroscopies. With 30% aqueous hydrogen peroxide as oxidant, benzyl alcohol was efficiently oxidized to benzaldehyde over reaction-controlled phase-transfer catalysts (Cpyr)_(3+x)PV_xMO_yW_(12-x-y)O_(40). Effects of the type of catalyst, the amount of catalyst and H_2O_2, the kind of solvent, reaction temperature and time were investigated. Under the optimal conditions, i.e., with 0.1 mol of benzyl alcohol, 0.04 mmol of(Cpyr)_5PV_2Mo_5W_5O_(40) catalyst and 0.1mol of 30% H_2O_2, reaction temperature 100℃, 10 mL water as the solvent, 88.51% conversion of benzyl alcohol and 96.06% selectivity for benzaldehyde were achieved within 8h.