丝光沸石分子筛催化甲苯与叔丁醇气相合成对叔丁基甲苯

Gas-Phase Synthesis of Para-tert-Butyltoluene from Toluene and tert-Butyl Alcohol over H-Mordenite Catalyst

丝光沸石作为催化剂,采用气相催化甲苯和叔丁醇合成对叔丁基甲苯,考察了反应条件和碱改性丝光沸石对催化活性的影响。采用XRD、NH3-TPD、FT-IR、比表面积测定等方法对催化剂进行了表征。实验结果表明:适宜的反应条件为反应温度180℃,进料体积空速4 mL/(g h),原料甲苯与叔丁醇物质的量比2:1,在此条件下,甲苯转化率达到29%,对叔丁基甲苯选择性达到最大值74%。碱改性后消除了催化剂的强酸中心,而增加了弱酸中心,但孔径变大,比表面积变小。催化活性有所提高,甲苯转化率和对叔丁基甲苯选择性分别提高了4%和7%。

Para-tert-Butyltoluene （PTBT） was synthesized from toluene and/err-butyl alcohol over H-mordenite catalyst by gas-phase catalysis. The effects of reaction conditions and modification of catalyst by alkali on the catalytic performance were investigated. The catalysts were characterized by XRD, NH3-TPD, FT-IR and N2 adsorption techniques. It was shown that the suitable reaction condition was as followings： reaction temperature was 180 ℃, liquid volumetric space velocity was 4 mL/（g-h） and ratio of toluene to tert-butyl alcohol was 2. Under the above reaction condition, the toluene conversion approached 29%, and the selectivity of PTBT reached the maximum of 74%. After modification on the catalyst by alkali, the strong acidic sites disappeared and weak acidic sites increased. The pore size increased and the specific surface area decreased. As a result, the catalytic performance was improved 4% of toluene conversion and 7% of PTBT selectivity, respectively.