CAJ | 학술논문

对比研究了二甲醚在氢型丝光沸石和吡啶修饰的氢型丝光沸石上的二甲醚羰基化反应.结果表明,吡啶预吸附大大提高了二甲醚羰基化反应的稳定性,并且在473K反应48h能够保持约30%的乙酸甲酯收率.原位红外光谱和NH3程序升温脱附研究发现,吡啶吸附在12元环内,而8元环内的酸性位基本不受干扰. 129Xe核磁共振研究表明,未经修饰的丝光沸石反应后孔道严重堵塞,而吡啶修饰的分子筛反应后孔道基本不变.因此,12元环内酸性位是积炭失活位,吡啶吸附抑制了12元环内积炭的生成,二甲醚羰基化反应能够在8元环内活性位上顺利进行.
대비연구료이갑미재경형사광비석화필정수식적경형사광비석상적이갑미탄기화반응.결과표명,필정예흡부대대제고료이갑미탄기화반응적은정성,병차재473K반응48h능구보지약30%적을산갑지수솔.원위홍외광보화NH3정서승온탈부연구발현,필정흡부재12원배내,이8원배내적산성위기본불수간우. 129Xe핵자공진연구표명,미경수식적사광비석반응후공도엄중도새,이필정수식적분자사반응후공도기본불변.인차,12원배내산성위시적탄실활위,필정흡부억제료12원배내적탄적생성,이갑미탄기화반응능구재8원배내활성위상순리진행.
The carbonylation of dimethyl ether to methyl acetate over H-mordenite (HMOR) and pyridine-modified HMOR was compared. The catalytic stability of HMOR was improved significantly by pyridine pre-adsorption, and a yield of methyl acetate ～30% was still ob-tained after 48 h on stream at 473 K. In situ infrared spectroscopy and ammonia temperature-programmed desorption revealed that pyridine preferentially occupied the acidic sites in 12-membered ring pores but not the acidic sites in 8-membered ring pores, 129Xe NMR studies suggested that the channels of HMOR were blocked by coke in the reaction but those in the pyridine-modified HMOR were not. The acidic sites in the 12-membered ring pores were responsible for the deactivation of HMOR, and the reaction can be directed to occur mainly on the acidic sties in the 8-membered ring pores by the selective adsorption of pyridine in the 12-membered ring pores.