磷钨酸、磷钼酸季铵盐催化环己烯环氧化

合成了具有 Q_3PX_4O_(16)Q=(CH_3)_2(C_nH_(2n+1))(CH_2Ph)N,n=12,14,16,18;X=W,MO]结构的磷钨酸、磷钼酸季铵盐催化剂,并用傅里叶变换红外光谱、元素分析、电感耦合等离子体发射光谱技术进行了表征。将上述催化剂用于催化环己烯合成环氧环己烷反应。实验结果表明,催化剂的结构相同时,磷钨酸季铵盐催化剂的活性高于磷钼酸季铵盐催化剂;加入碱金属无机盐助催化剂,能显著提高目的产物的收率;并探讨了环氧环己烷收率与催化剂中有效碳数的关系。采用均匀实验设计优化出环己烯环氧化反应的条件,即磷钨酸季铵盐催化剂用量0.52 mmol,助催化剂用量1.20 mmol,溶剂二氯甲烷用量35 mL,环己烯与 H_2O_2的摩尔比3.75,反应温度40℃,反应时间105 min。在该反应条件下,环氧环己烷的收率为90.72%～97.74%。

Heteropolyphosphatotungstate or Heteropolyphosphatomolybdate Catalysts in Epoxidation of Cyclohexene

A series of heteropolyphosphatotungstate or heteropolyphosphatomolybdate catalysts with Q_3PX_4O_(16)Q=(CH_3)_2(C_8H_(2n+1))(CH_2Ph)N,n=12,14,16,18;X=W,Mo]structures were prepared and characterized by means of FFIR,elemental analysis and ICP.The catalytic behavior of Q_3PX_4O_(16) catalysts in epoxidation of cyclohexene to cyclohexene oxide was studied.The activities of W series are higher than that of Mo series with same structures.Yield of cyclohexene oxide is improved by using inorganic alkali salts as cocatalyst,due to the inhibition of hydrolysis.Relationships between yield of cyclohexene oxide and number of effective C atoms in different catalysts were studied.SPSS methods were used to optimize the results of uniform experiment of W series.Under optimal reaction conditions:catalyst dosage 0.52 mmol,mass of cocatalyst 1.20 mmol,volume of solvent CH_2Cl_2 35 mE,n(cyclohexene):n(H_2O_2)3.75,reaction temperature 40℃ and reaction time 105 min,yield to cyclohexene oxide is 90.72%-97.74%.