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采用酒石酸对USY分子筛进行改性处理,通过XRD、NH3-TPD和BET进行了表征,考察了酒石酸加入量对USY结构及催化性能的影响。实验表明,酒石酸改性后催化剂,比表面积略有下降,结晶度提高,催化性能有了大幅提升。随着酒石酸的进一步加入,分子筛比表面积降低,结晶度、酸量、酸强度先提高后下降,明显呈现了两个极值。以改性后的USY分子筛作为催化剂对反应进行了研究,每4 g USY分子筛中加入30 m L浓度为0.1 mmol/L的酒石酸时,催化剂的性能最佳,反应温度120℃,反应空速1 h-1,甲苯与叔丁醇摩尔比为2∶1,平均转化率为34.2%,选择性达到75%。
The USY molecular sieve was modified by tartaric acid and characterized by XRD, NH3-TPD and BET. The effects of tartaric acid addition amount on the structure and catalytic performance of USY were investigated. Experiments show that the tartaric acid modified catalyst, a slight decrease in specific surface area, increased crystallinity, catalytic performance has been significantly improved. With the further addition of tartaric acid, the molecular sieve surface area decreased, the crystallinity, acidity, acid strength first increased and then decreased, showing two extreme values. The modified USY zeolite was used as a catalyst to study the reaction. When 30 mL L-1 tartaric acid was added to 4 g USY zeolite, the catalyst exhibited the best performance with a reaction temperature of 120 ℃ and a reaction space velocity of 1 h-1. The mole ratio of toluene to t-butyl alcohol was 2: 1, the average conversion was 34.2% and the selectivity reached 75%.