Presidential Young Investigator Award

超临界流体(SCF)越来越受到人们的青睐，特别是作为萃取剂。通用食品公司已经使用超临界流体二氧化碳从咖啡豆中提取咖啡因，环境保护局正在试验使用超临界流体来清理受污染的GAC、土壤和污泥。然而，对超临界流体的热力学仍然缺乏基本的了解，因此这些重要的过程继续被设计，至少在一定程度上是经验性的。我之前的研究最显著的贡献是开发了一种光谱技术，该技术显示了当在临界点附近操作时，超临界流体溶剂在溶质周围的局部密度大大丰富。这是第一个支持这种观点的证据，即即使在溶剂和溶质都是非极性的情况下，超临界流体中也会发生“聚集”。PI认为，这种聚集和其他特定的化学相互作用是传统状态方程模型中缺失的主要组成部分，不幸的是，这些模型无法准确预测SCF的相行为。

Supercritical fluids (SCF) have become increasingly popular, especially as extraction solvents. Already, General Foods uses SCF carbon dioxide to extract caffeine from coffee beans and the EPA is experimenting with the use of SCF's to clean up contaminated GAC, soils and sludges. Basic understanding of the thermodynamics of SCF's is, however, still lacking so that these important processes continue to be designed at least somewhat empirically. The most striking contribution from my prior research is the development of a spectroscopic technique that showed greatly enriched local densities of SCF solvents around solutes when operating in the region near the critical point. This was the first evidence of its kind to support the idea that "clustering" occurs in SCF's even when both the solvent and the solute are nonpolar. The PI believes that this clustering and other specific chemical interactions are the main components missing in traditional equation of state models that, unfortunately, are not able to accurately predict SCF phase behavior.