Ce改性HZSM-5分子筛催化甲醇与丁烯耦合转化制丙烯性能研究

摘要/Abstract

摘要： 为了进一步提高HZSM-5分子筛在甲醇与丁烯耦合转化制丙烯反应中的催化性能，采用浸渍法对HZSM-5分子筛进行Ce改性，得到了一系列具有不同Ce负载量的xCe/HZSM-5催化剂。考察了Ce负载量和反应条件（甲醇与丁烯物质的量之比、反应温度和空时）对催化性能的影响，并结合催化剂表征结果，分析了Ce改性对催化性能和物化性质的影响，探讨了xCe/HZSM-5催化剂的构效关系。结果表明，在温度550 ℃、压力0.1 MPa、甲醇与丁烯物质的量之比0.8、空时2.3 (g_cat.h)/mol_CH2的最佳反应条件下，Ce负载量（w）为2.5%的2.5Ce/HZSM-5催化剂具有最高的丙烯收率，为41.9%。Ce与HZSM-5分子筛上羟基官能团（OH）发生相互作用，降低了B酸酸量，同时生成新的L酸中心Ce(OH)²⁺，调变了催化剂表面酸中心密度和酸类型分布，提高了丙烯选择性和收率。

关键词: 甲醇, 丁烯, 丙烯, Ce改性, HZSM-5分子筛

Abstract: In order to further improve the catalytic performance of HZSM-5 zeolite in the coupling conversion of methanol and butylene to propylene, a series of Ce-modified HZSM-5 (xCe/HZSM-5) catalysts with different Ce-loading were prepared by impregnation method. The effects of Ce-loading and reaction conditions (methanol/butylene molar ratio, reaction temperature and space time) on the catalytic performance of catalysts were systematically investigated. Combined with the catalyst characterization results, the effects of Ce modification on the performance and physicochemical properties of catalysts were analyzed, and the structure-activity relationship of xCe/HZSM-5 catalyst was discussed. The results showed that under the optimum reaction conditions including atemperature of 550 ℃, a pressure of 0.1 MPa ,a molar ratio of methanol/butylene of 0.8 and a space time of 2.3(g_cat.h)/mol_CH2, 2.5Ce/HZSM-5 catalyst with 2.5% Ce loading (w) showed the highest propylene yield of 41.9%. The interaction between Ce and hydroxyl groups (OH) on the HZSM-5 zeolite decreased the Bronsted (B) acid amount and formed a new Lewis (L) acid site Ce(OH)²⁺, which caused the reduction of the ratio of B/L acid sites, thus, the selectivity and yield of propylene were improved.

Key words: methanol, butylene, propylene, cerium-modified, HZSM-5 zeolite

白婷朱航王进曹彬. Ce改性HZSM-5分子筛催化甲醇与丁烯耦合转化制丙烯性能研究[J]. 石油炼制与化工, 2024, 55(6): 74-82.

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