氧化物改性MCM-22上甲苯与甲醇的烷基化性能研究

STUDY ON ALKYLATION OF TOLUENE WITH METHANOL OVER OXIDE-MODIFIED MCM-22 ZEOLITE

采用动态水热法合成了MCM-22分子筛,以混合稀土、乙酸镁、硅酯等为改性剂,采用浸渍法对其进行改性。采用NH3-TPD、IR等表征了改性前后催化剂的酸性,考察了改性MCM-22分子筛上甲苯与甲醇烷基化合成对二甲苯的反应性能。结果表明,H型MCM-22分子筛在该反应中具有很高的催化活性,但是对二甲苯和二甲苯的选择性都较低。经过混合稀土、醋酸镁改性后,对二甲苯的选择性达到62.61%,催化剂综合性能明显提高。

MCM-22 zeolite was synthesized under hydrothermal conditions and modified by impregnating treatment with rare earths, magnesium acetate or silicone as modifiers. NH3-TPD, IR were used to characterize the acidity of the catalyst samples before and after modification, and the alkylation of toluene with methanol over modified MCM-22 was studied. The experimental results showed that H-MCM-22 possessed a high activity on alkylation of toluene with methanol, but low paraxylene and xylene selectivity. After modified with rare earths and magnesium acetate, the selectivity of paraxylene reached 62.61% and the compositive properties of the catalyst was improved.