Supercritical CO2 and CHF3 as Alternative Solvents for Pollution Prevention

化学部的这一奖项支持了詹姆斯·M. 弗吉尼亚理工学院化学系的坦科和 州立大学，关于使用超临界流体作为环境 化学反应的良性溶剂。 该奖项是在 1995年NSF/EPA可持续环境技术活动 环境研究伙伴关系。 二氧化碳和氟仿 将检查它们作为自由基反应溶剂的潜力。 预期这两种溶剂对自由基是惰性的，并且已知 在中等温度和压力下变成超临界。 的 该项目的目标是确定激进的范围和限制， 反应服从超临界流体条件，开发新的 用于合成高价值有机材料的合成方法，以及 探索使用超临界流体的意义， 有机反应的基本物理原理。 许多有机反应是通过一种反应机理进行的， 带有未成对电子的物质称为自由基。 例如 反应是涉及将氯或溴加成到 烃或延长烃链。 在这些反应中， 重要的是溶剂不与自由基反应。 经常 溶剂也在自由基物质的形成中起作用。 在许多情况下，苯和四氯化碳是 这些反应，但它们对环境有害。 本研究 将测试两种对环境无害的替代溶剂 以适用于涉及自由基的有机反应。

This award in the Chemistry Division supports research by Dr. James M. Tanko of the Chemistry Department, Virginia Polytechnic Institute and State University, on the use of supercritical fluids as environmentally benign solvents for chemical reactions. The award is made in the Technology for a Sustainable Environment activity of the 1995 NSF/EPA Partnership for Environmental Research. Carbon dioxide and fluoroform will be examined for their potential as solvents for radical reactions. Both solvents are expected to be inert toward free radicals and are known to become supercritical at moderate temperatures and pressures. The goals of the project are to identify the scope and limitations of radical reactions amenable to supercritical fluid conditions, to develop new synthetic methods for the synthesis of high-value organic materials, and to explore the implications of the use of supercritical fluids for fundamental physical principles of organic reactivity. Many organic reactions proceed by a mechanism which involves a reactive species with an unpaired electron called a free radical. Example reactions are those involving addition of chlorine or bromine to hydrocarbons or lengthening of hydrocarbon chains. In these reactions, it is important that the solvent not react with the free radical. Often the solvent also plays a role in the formation of the radical species. In many cases benzene and carbon tetrachloride are effective solvents for such reactions, but they are environmentally harmful. In this research two alternate solvents which are environmentally benign will be tested for suitability in organic reactions involving free radicals.