ZSM-11分子筛改性及其在苯、甲醇烷基化反应中的应用

采用NaOH溶液碱处理、HCl溶液酸处理、负载Mg等方法对ZSM-11分子筛进行改性。采用XRD,FE-SEM,NH3-TPD,N2吸附-脱附等方法对改性前后的分子筛及催化剂进行表征,结果表明:改性后的分子筛中引入了大量的介孔,但最大限度地保留了分子筛ZSM-11的晶型和微孔,负载Mg后,容易产生积炭副反应的强酸中心被覆盖。将改性后的分子筛催化剂用于苯、甲醇的烷基化反应中,在反应温度为460℃、反应压力为0.2 MPa、质量空速为3h-1、n(苯)∶n(甲醇)=1的条件下,苯转化率达到52.60%,甲苯、二甲苯总选择性达到89.91%,二甲苯选择性达到34.08%。苯、甲醇烷基化反应的稳定性实验结果表明,改性后分子筛催化剂在200h内保持了反应活性的相对稳定。

APPLICATION OF MODIFIED ZSM-11 IN BENZENE ALKYLATION WITH METHANOL

A series of ZSM-11 was modified by NaOH, HCl acid and Mg loading. The samples were characterized by XRD、FE-SEM、NH3-TPD and BET techniques, respectively. The results show that the modified samples generate a number of mesopores, while aximum crystallinity and micropores are retained. The strong acid centers of the zeolite that facilitate carbon deposition reaction are covered by Mg. Alkylation of benzene with methanol (n（benzene）：n（methanol）=1) was performed over the modified ZSM-11 catalysts under the conditions of 460 ℃, 0.2 MPa and the weight hourly space velocity of 3 h-1. The benzene conversion is 52.60%. The total selectivity of toluene and xylene is 89.91%. The xylene selectivity is 34.08%. The reactivity of modified ZSM-11 is stable in 200 hours alkylation reaction.