负载型KX/KZSM-5双沸石催化甲苯甲醇侧链烷基化反应的研究

Study on side chain alkylation of toluene with methanol over KX/KZSM-5 binary zeolite catalysts

通过离子交换法制备了KX和KZSM-5催化剂,浸渍法制备了1%K2O-KX和3%K2O-KZSM-5催化剂,机械混磨法制备了KX/3%K2O-KZSM-5催化剂,并考察了其甲苯甲醇烷基化反应的催化性能。甲苯甲醇在碱性较强的KX上发生侧链烷基化反应生成苯乙烯和乙苯,同时伴随着甲醇大量分解生成副产物CO和H2,在碱性较弱的KZSM-5上发生苯环烷基化反应生成二甲苯。KX负载1%质量分数的K2O后甲苯甲醇侧链烷基化反应的活性明显提高,但甲醇分解也更加严重。KX与负载3%质量分数的K2O的KZSM-5均匀机械混合制得催化剂,表现出较高的甲苯甲醇侧链烷基化反应的活性,且通过对反应物的选择性吸附在保持与1%K2O-KX活性相同的同时使甲醇的分解得到一定程度的抑制。

KX and KZSM-5 catalysts were prepared by ion exchange method, I%K20-KX catalyst was prepared by impregnation method, and KX/3% K20-KZSM-5 catalyst was prepared by mechanically blending and grinding. Their catalytic perfm＇mances for alkylation of toluene with methanol were investigated. For the stlonger basic KX, the main products were styrene and ethylbenzene with substantial byproduct CO and H2 from methanol decomposition. For the weaker basic KZSM-5, the main product was xylene. The catalytic activity of I%K20-KX were higher than that of KX, but more ammmt of methanol decomposed to CO and H2. The catalytic activity of KX/3%K20-KZSM-5 was similar to that of IK_,O-KX, however, it could inhibit the decomposition of nlethanol due to its selective adsorption to the reactants.