负载磷钨酸铵的溶胶-凝胶法制备及催化苯硝化反应的研究

Nitration of Benzene Catalyzed by Supported Ammonium Phosphotungstate Catalyst

摘要: 以正硅酸乙酯为硅源,利用溶胶-凝胶法制备了负载磷钨酸杂多酸铵盐催化剂,利用XRD和IR对催化剂进行了表征,并以苯硝化为模型反应,初步评价了催化剂对硝化反应的催化性能.结果表明,负载催化剂保持了非负载磷钨酸铵杂多酸盐的Keggin结构;负载催化剂对苯硝化反应具有较高的催化活性,反应时间、催化剂用量以及硝酸与苯体积比对催化苯硝化反应有较大的影响,当反应温度为70℃时,最佳实验条件为:5mL苯、15mL硝酸、0.5g催化剂、反应5h;而且苯硝化反应产物中无多硝基苯生成,硝基苯的选择性高;多次使用后,负载催化剂仍表现出了较强的催化活性.

Abstract: Supported ammonium phosphotungstate catalyst was prepared by sol-gel method and characterized by X-ray diffraction(XRD) and IR spectra,and catalytic activity of catalyst in nitration of benzene was tested. Experiments results indicated that supported catalyst still presented the Keggin structure of ammonium phosphotungstate catalyst and exhibited high nitration reaction catalytic activity and high selectivity to mononitrobenzene. The best yield rate was obtained under reaction conditions as follows:the volu...