磷钨酸季铵盐催化环己烯合成己二酸

Synthesis of Adipic Acid from Cyclohexene with Quaternary Ammonium Phosphotungstate as Catalyst

合成了两种不同阳离子结构的磷钨酸季铵盐催化剂磷钨酸十八烷基二甲基苄铵和磷钨酸十六烷基吡啶铵,并用红外光谱及元素分析法对其结构进行了表征。以w(H2O2)=30%水溶液为氧源催化环己烯合成了己二酸,讨论了磷钨酸季铵盐用量、H2O2与环己烯摩尔比、反应时间、反应温度等因素对反应的影响。实验结果表明,磷钨酸十六烷基吡啶铵的催化活性优于磷钨酸十八烷基二甲基苄铵;以磷钨酸十六烷基吡啶铵为催化剂,在反应温度95℃、反应时间5.5h、n(H2O2)∶n(环己烯)=5.0(以0.045m ol环己烯计)、催化剂用量0.4mm ol的条件下,己二酸的平均收率达67.72%,催化剂的平均回收率达54.12%。

Two kinds of quatemary ammonium phosphotungstates, hexadecylpyridyl ammonium phosphotungstate and octadecyldimethylbenzl ammonium phosphotungstate, were synthesized. The phosphotungstates were characterized by means of IR and elemental analysis. Synthesis of adipic acid from cyclohexene was investigated with 30% （mass fraction）hydrogen peroxide as oxidant and synthesized quaternary ammonium phosphotungstates as catalysts. After reaction, catalysts can be separated from reaction system and be mostly recovered. Effects of catalyst dosage ,mole ratio of hydrogen peroxide to cyclohexene, reaction time and temperature on reaction were studied. Catalytic activity of hexadecylpyridyl ammonium phosphotungstate is higher than that of octadecyldimethylbenzl ammonium phosphotungstate. When n （ H2O2 ） ： n （cyclohexene） 5.0 （ based on 0.045 mol cyclohexene ）, catalyst dosage 0.4 mmol, reaction temperature 95 ℃ and time 5.5 h, hexadecylpyridyl ammonium phosphotungstate as catalyst, average yield of adipic acid can reach 67.72% and average recovery of catalyst was 54.12%.