三氯化铝固载化的新方法

Al Cl3是化工、石油炼制和制药工业中广泛应用的重要催化剂之一 .但由于它具有腐蚀性 ,与产物分离麻烦以及产生大量污水等缺点 ,其使用日益受到限制 .为解决上述问题 ,人们对其固载化进行了长达 50多年的研究 ,研究的重点是通过化学反应把 Al Cl3嫁接到 γ-Al2 O3和 Si O2 等常用载体上 .主要方法有两种 :一种是气 -固反应法 1～ 4 ] :先将 Al Cl3升华 ,再与固体载体反应 ;另一种是溶剂反应法5～ 6] :将 Al Cl3溶解于 CCl4 ,CHCl3等溶剂中 ,通过浸泡、回馏等方法使 Al Cl3与固体载体反应 .一般认为 ,Al Cl3固载化机理是 Al Cl3…

New Approaches to Immobilization of Aluminium Chloride on γ-Al2O3

The method of preparation of AlCl₃ catalyst immobilized on γ-Al₂O₃ was investigated. AlCl₃ generated by reacting CCl₄ with pure γ-Al₂O₃ at 500℃ and γ-Al₂O₃ with bimodal meso-and macro-pore structure were used as immobilizing agent and support, respectively, to prepare the catalyst. The effect of various factors of immobilization conditions on catalytic property in isobutene polymerization was examined. The catalyst, in which the mass fraction of AlCl_x is about 7.5 and x=2.2, showed a high activity, selectivity and stability, and no considerable differences in the catalytic behavior were founDIn the following ranges: reaction temperature, 300-400 ℃; reaction time, 0.5-4.0 h; flow of CCl₄ of adding, 1.15-2.01 mL/h for 15 mL γ-Al₂O₃. Additionally, it was shown that the catalytic property in isobutene polymerization is not only dependent on the nature of support, but also on its geometric structure. Compared with the catalysts having micro-porous and meso-porous structure which showed a poor stability, the catalyst with meso-and macro-pore bimodal structure exhibited a very high stability, and was supposed to be most suitable one, anDIt was ascribed to that in the case of the latter, harmfuLInfluence of intraparticle diffusion caused by "pore clogging" of large product molecules in the pore channel effectively reduced.