在超临界二氧化碳中对1,n-终端二醇进行选择性单一保护:这是溶剂调节性脱对称化的明显例子
Peter Licence1, William K Gray, Maia Sokolova
1School of Chemistry, The University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom.
Journal of the American Chemical Society
|January 6, 2005
概括
使用二醇和醇的超临界CO2反应可以调整为支持单乙烯或双乙烯产品. 根据反应混合物中压力诱导的变化而发生的选择性转移.
科学领域:
- 化学工程是化学工程的重要组成部分.
- 有机化学 有机化学
- 绿色化学 绿色化学
背景情况:
- 超临界流体提供独特的反应环境.
- 选择性以太合成对于各种化学应用至关重要.
- 控制产品在反应中的分布是一个关键的挑战.
研究的目的:
- 研究从二醇和酒精中合成单乙烯和双乙烯的合成.
- 探索超临界CO2条件对反应选择性的影响.
- 了解阶段行为在决定产品分配中的作用.
主要方法:
- 使用1,n端二醇 (n=3,6) 和简单醇 (MeOH,EtOH,n-PrOH) 进行了反应.
- 使用超临界二氧化碳 (scCO2) 作为反应介质,使用Amberlyst 15作为酸催化剂.
- 系统地改变反应温度 (150°C) 和压力 (50-200 bar),以研究选择性变化.
主要成果:
- 通过改变反应压力,成功切换了单乙和双乙产品之间的选择性.
- 在150°C和50巴的温度下,反应有利于二乙烯乙烯的形成 (1:20比).
- 在150°C和200巴的温度下,反应有利于非对称的单乙烯形成 (9:1比).
- 观察到的选择性切换与反应混合物的相位相关 (单相与双相).
结论:
- 在超临界CO2中反应相态度是控制以太合成选择性的关键因素.
- 单相条件有利于单相以太的形成,而双相条件有利于双相以太的形成.
- 这项研究提供了一种方法,用于调整使用scCO2的乙化反应的选择性.
相关概念视频
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