催化学报

催化学报 ›› 2010, Vol. 31 ›› Issue (7): 729-738.

• 研究论文 • 上一篇    下一篇

预吸附吡啶增强二甲醚在丝光沸石上羰基化反应的稳定性

刘俊龙 1, 薛会福 1, 黄秀敏 1, 吴培豪 2, 黄信炅 3, 刘尚斌 2, 申文杰 1   

  1. 1 中国科学院大连化学物理研究所催化基础国家重点实验室, 辽宁大连 116023 2“中央”研究院原子与分子科学研究所, 台湾台北 10617 3 台湾大学化学系, 台湾台北 10617
  • 收稿日期:2010-07-25 出版日期:2010-07-25 发布日期:2010-07-25

Stability Enhancement of H-Mordenite in Dimethyl Ether Carbonylation to Methyl Acetate by Pre-adsorption of Pyridine

LIU Junlong1, XUE Huifu1, HUANG Xiumin1, WU Pei-Hao2, HUANG Shing-Jong3, LIU Shang-Bin2,*, SHEN Wenjie1,#   

  1. 1State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China 2Institute of Atomic and Molecular Sciences, “Academia Sinica”, Taipei 10617, Taiwan, China 3Department of Chemistry, Taiwan University, Taipei 10617, Taiwan, China
  • Received:2010-07-25 Online:2010-07-25 Published:2010-07-25

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摘要： 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 473 K 反应 48 h 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.

关键词: 二甲醚, 羰基化, 乙酸甲酯, 丝光沸石, 吡啶, 稳定性

Abstract: 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 obtained after 48 h on stream at 473 K. In situ infrared spectroscopy and ammonia temperature-programmed desorption revealed that pyridine prefer-entially 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.

Key words: dimethyl ether, carbonylation, methyl acetate, H-mordenite, pyridine, stability