负载型磷钨酸催化剂的制备及催化合成ＥＴＢＥ的性能研究

采用水热法合成纯硅介孔分子筛Si-MCM-41, 并用浸渍法将磷钨酸(PWA)负载到介孔分子筛Si-MCM-41上, 制得了磷钨酸负载量不同的催化剂x%PWA/MCM-41. 利用XRD, FT-IR, Py-IR, BET, TEM对载体和催化剂进行分析. 结果表明, 负载后的PWA颗粒粒径明显减小, 粒径约为10个纳米, PWA在载体表面实现了均匀分布, 通过叔丁醇和乙醇在高压反应釜内生成乙基叔丁基醚的反应测试催化剂的催化性能. 结果表明, 负载型催化剂和纯PWA相比, 前者使叔丁醇(TBA)的转化率、ETBE的选择性有很大提高, 当磷钨酸负载量为30%时TBA的转化率最大. 最优的催化剂制备及反应条件是: 载体550 ℃煅烧脱模, PWA负载量为30%, 催化剂煅烧温度为300 ℃, 醚化反应温度为120 ℃, 乙醇与叔丁醇的摩尔比为2∶ 1, 催化剂的用量为1.4 g.

Preparation 12-Tungstophosphoric acid Supported on MCM-41 for Etherization of Ethanol with tert-Butyl Alcohol

The mesoporous Si-MCM-41 was synthesized by hydrothermal method and various wt. % (10-50 wt. % ) of PWA were loaded on Si-MCM-41 by wet impregnation method. The synthesized Si-MCM-41 and PWA-loaded catalysts were characterized by XRD, FT-IR, Py-IR ,BET surface area, TEM techniques. The results showed that the particle of the supported catalyst obviously became smaller and the diameter was about 10 nanometers, PWA was evenly distributed at the surface of Si-MCM-41. Through the reaction of tert-butyl alcohol and ethanol at high pressure reactor to generate ethyl tert-butyl ether to test the catalytic capability of catalysts . The result was that the conversion and selectivity were enhanced after being loaded. When PWA loading for 30% , The conversion of TBA was the highest. The optimal catalyst preparation and reaction conditions are:MCM-41 was calcined at 550℃ ,the loading of PWA was 30% , the preparation temperature of catalyst was 300 ℃ , the reaction of etherification was 120℃ ,the molar ratio of ethanol and tert-butyl alcohol was 2:1, the amount of catalyst was 1.4 g.