过氧化磷钨杂多酸季铵盐催化氧化苯乙烯的研究

Study on Oxidation of Styrene by Quaternary Ammonium Peroxotungsto Phosphate Catalysts

分别采用不同的季铵盐四丁基氯化铵(Bu4NCl)、三辛基甲基氯化铵(C8H17)3CH3NCl和溴化十六烷基吡啶(π-C5H5NC16H33Br)与钨酸或钨酸钠、磷钨酸反应制得过氧化磷钨杂多酸季铵盐Q3+{PO4[W(O)O4]3[W(O)O4]}3-(Q+:季铵盐正离子R4N+),以其为催化剂、二氯乙烷为溶剂、H2O2为氧化剂氧化苯乙烯,结果发现过氧化磷钨三辛基甲基铵有很好的催化活性,在反应温度55℃、pH=3.0、n(催化剂)∶n(苯乙烯)∶n(H2O2)=1∶100∶120时,苯乙烯的转化率为40.2%,环氧苯乙烷的选择性为39.2%。

By reactions of three kinds of quaternary ammonium salts such as Bu4NCl, （C8 H17 ）3CH3NCl and n-C5 HsNC16 H33Br with H2 WO4 or Na2WO4, a series of quaternary ammonium peroxotungsto phosphate catalysts Q3^＋ {PO4 [W（O）04 ]3 [W（O）04 ]}^3- （Q＋. quaternary ammonium cationR4 N^＋） were prepared and their catalytic activities for expoxidant of styrene were studied with 1,2-dichloroethane as solvent and H2O2 as oxidation. The results showed that [（C8 Ha7 ）3CH3 N^＋ ]3 {PO4 [W（O）O413 [W（O）O4 ] }^3- had high catalytic activity, and the optimum conditions for it were as follows.the reaction temperature was 55℃ ,the pH value was 3.0 and n（catalyst） ： n（styrene） ： n（H2O2）=1 ： 100 ： 120. Under above conditions,the conversion of styrene reached up to 40.2% and the selectivity of epoxy ethylbenzene was 39.2%.