苯与1,2,4-三甲苯在改性纳米HZSM-5上的烷基转移反应

TRANSALKYLATION OF BENZENE AND 1,2,4-TRIMETHYLBENZENE OVER MODIFIED NANOSIZED HZSM-5

研究了柠檬酸处理、水蒸气处理以及水蒸气处理加柠檬酸处理复合改性对纳米HZSM.5分子筛催化剂在苯与1,2,4-三甲苯烷基转移反应中催化性能的影响。结果表明,柠檬酸处理改善了催化剂的吸附扩散性能,从而提高了催化剂活性;水蒸气处理脱除了大部分可利用的酸位,催化剂的活性稳定性有所降低;与母体催化剂相比,水蒸气处理加柠檬酸处理的复合改性保留了催化剂的烷基转移活性中心,可提高催化剂的稳定性。

The effect of nanosized HZSM-5 modification methods including citric acid treatment, steam treatment and steam-citric acid treatment, on the catalytic activity and stability of nanosized HZSM-5 during aromatics transalkylation reaction was investigated. The results showed that citric acid treatment could improve the adsorption-diffusion performance of the catalyst and thus increased the activity of nanosized HZSM-5. When nanosized HZSM-5 was steamed at 350℃, most of the useful acid sites were eliminated, which led to the decrease of both activity and stability of the catalyst. The combined modification of steam-citric acid treatment could keep the acid sites for transalkylation reaction and increase catalyst stability simultaneously, which proposed a suitable method to develop catalysts for the transalkylation of benzene and 1,2, 4-trimethylbenzene.