Al_2O_3-HZSM-5催化甲醇脱水制二甲醚的反应动力学  

Reaction Kinetics of Methanol Dehydration over Combined AI203-HZSM-5 Solid Acids

作　　者：张立伟[1] 吴佩[1] 金顶峰[1] 侯昭胤[1] 费金华[1] 

机构地区：[1]浙江大学理学院化学系催化研究所,浙江杭州310028

出　　处：《化学反应工程与工艺》2008年第4期358-362,380,共6页Chemical Reaction Engineering and Technology

基　　金：科技部973项目(2007CB210207);863项目(2007AA05Z415);浙江省自然科学基金资助(Z406142)

摘　　要：采用机械混合法制备了不同组成的 Al_2O_3-HZSM-5复合固体酸催化剂,采用 N_2吸附和 X 射线衍射(XRD)等对催化剂结构进行表征,考察了催化剂在甲醇脱水制二甲醚反应中的活性并研究其反应动力学。结果表明,添加质量分数为20%的 Al_2O_3(20%)-HZSM-5复合固体酸催化剂具有较好的反应活性,在该催化剂上进行甲醇脱水制二甲醚的反应符合 Rideal-Eley 分子吸附机理,根据实验数据计算得到甲醇脱水反应的活化能为38.42 kJ/mol,指前因子为1 171.3 min^(-1)。A series of combined Al2O3-HZSM-5 solid acids were prepared by mechanically mixing Al2O3 and HZSM-5, and characterized by X-ray diffraction （XRD） and N2 adsorption. The catalytic performance of the combined Al2O3-HZSM-5 solid acids catalysts for synthesis of dimethyl ether （DME） and the reaction kinetics of methanol dehydration over combined Al2O3-HZSM-5 solid acid with different mass fraction of Al2O3 were investigated in a fixed bed reactor. It was found that suitable amount of Al2O3 could improve the catalytic activity of Al2O3-HZSM-5 catalyst and when mass fraction of Al2O3 was 20%, the Al2O3-HZSM-5 exhibited higher activity than that of pure Al2O3 and pure HZSM-5. Mechanism study indicated that methanol dehydration over Al2O3-HZSM-5 catalysts （Al2O3 mass fraction 20%） agreed with the Rideal-Eley molecule adsorption model well, and the activation energy was 38.42kJ/mol, and the pre-exponential factor was 1 171.3min^-1.

关 键 词：氧化铝 分子筛 固体酸 甲醇脱水 二甲醚 反应动力学 

分 类 号：TQ223.24[化学工程—有机化工] O643.36[理学—物理化学]