在水中的基的基添加反应的绝对速率常数
L Zhang1, W R Dolbier, B Sheeller
1Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200, USA.
Journal of the American Chemical Society
|May 30, 2002
概括
测量了对水溶性烯添加化基的速率常数. 在水中增强的速率表明极性溶剂稳定了这个重要的化学反应的过渡状态.
科学领域:
- 物理化学 物理化学
- 有机化学 有机化学
- 化学动力学 化学动力学
背景情况:
- 在有机合成和聚合物化学中,了解极端加法反应至关重要.
- 溶剂极性对反应机制的影响,特别是过渡状态稳定,是研究的一个关键领域.
- 基及其反应性在化学转化中提出了独特的挑战和机会.
研究的目的:
- 量化电友基 (*R(f) SO(3) ((-)) 添加到水溶性基的绝对速率常数.
- 研究离子和碳酸盐替代剂对烯溶解性和反应性的影响.
- 为了比较极性溶剂 (水) 与非极性有机溶剂的反应性.
主要方法:
- 激光闪光光分解被用来产生激素并启动加法反应.
- 使用光谱技术监测反应动力学并确定速率常数.
- 一系列含有不同离子替代物的水溶性基因被合成并使用.
主要成果:
- 在水中成功测量了对*R(f) SO(3)(-) 基的绝对速率常数,对所研究的基基进行了添加.
- 与非极性有机溶剂中类似反应相比,观察到的速率常数明显高 (3-9倍).
- 基上有离子,碳酸盐替代物的存在影响了它们在水中的可溶性和反应性.
结论:
- 在水中反应速度的提高是由于极性溶剂稳定了极性过渡状态.
- 水的溶解和稳定带电或极性中间体的能力在加速这些激素加法反应中起着重要作用.
- 这些发现为水性介质中基反应的机制提供了宝贵的见解,这与环境和生物应用有关.
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