有证据表明,甲醇-olefin 过程的启动是通过在酸性泽奥利特催化剂上的反应性表面甲氧基组
Wei Wang1, Andreas Buchholz, Michael Seiler
1Institute of Chemical Technology, University of Stuttgart, D-70550 Stuttgart, Germany.
Journal of the American Chemical Society
|December 5, 2003
概括
甲醇-烯 (MTO) 催化的初始步骤涉及表面甲氧基组形成碳化合物. 这些甲基物种可以直接转化为碳化合物或甲基化其他分子,启动MTO过程.
科学领域:
- 催化剂是一种催化剂.
- 材料科学 材料科学 材料科学
- 有机化学 有机化学
背景情况:
- 在酸性焦石上进行的甲醇到烯酸 (MTO) 工艺对于生产轻烯酸至关重要.
- "碳化合物池"机制主导着MTO转换,但最初的C-C键形成仍然不清楚.
- 了解动力"诱导周期"是优化MTO过程的关键.
研究的目的:
- 为了研究MTO过程中纯表面甲基团的反应性.
- 为了阐明MTO诱导期期间的初始C-C键形成路径.
- 为了证明碳化合物的直接形成来自甲基物种.
主要方法:
- 在低于473K的焦化物催化剂 (H-Y,H-ZSM-5,H-SAPO-34) 上制备纯表面甲氧基[SiO(CH(3)) Al.
- 在受控反应研究中使用了停止流程协议.
- 在现场使用 (13)C MAS 核磁共振光谱来监测甲基物种的反应.
- 用烯和环素等探针分子研究甲基化反应.
主要成果:
- 表面的甲基物种与水反应形成甲醇,表明低温平衡.
- 甲基组甲基化二烯和环二烯分别在433K和493K.
- 在523K以上的流量条件下,观察到纯甲氧基直接转化为碳化合物.
- 这种直接转换提供了在MTO诱导期内碳化合物形成的证据.
结论:
- 表面甲氧基团是MTO反应中的关键中间体,启动碳化合物形成.
- 该研究表明,碳化合物可以直接从甲基物种中形成,从而澄清了诱导期.
- 现有有机分子的甲氧基基甲基化有助于稳态MTO中的反应性碳化合物池.
相关概念视频
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