Solvation in Supercritical Fluids

宾夕法尼亚州立大学的马克·马龙塞利教授得到了实验物理化学的资助，负责对超临界流体中分子的溶剂化性质进行实验和理论研究。目前，在超快溶液动力学的这一子领域，结果中存在异常，可被解释为溶质局部的密度不均匀(尽管这一点仍有争议)，因此，超临界流体比之前认为的要复杂得多。我们将对一个简单的非反应性溶质/超临界溶剂体系进行定量建模，然后进行模拟，从空间和动态的角度观察分子间的相互作用。将建立分析模型，人们可以利用众所周知的溶质和溶剂性质来预测溶剂化效应。该模型将用于预测在不同温度和压力下超临界流体中溶质扩散、松弛和化学反应速率的实验观测。马龙塞利教授将在进行理论工作的同时进行实验。超临界二氧化碳中的菲是一种正在探索的化学体系。这项工作特别及时，因为人们对超临界溶剂的广泛应用感兴趣，如环境友好的处理和修复以及分离和提取。超临界溶剂化具有极其重要的工业应用，对这一现象的更完整的理论理解将具有重要的影响。

Professor Mark Maroncelli of Pennsylvania State University is supported by a grant from Experimental Physical Chemistry to perform experimental and theoretical studies on the nature of solvation of molecules in supercritical fluids. Currently in this subarea of ultrafast solution dynamics, there are anomalies in the results that may be interpreted as density inhomogeneities local to the solute (although this is still controversial) and, therefore, supercritical fluids are more complex than previously thought. A simple nonreactive solute/supercritical solvent system will be quantitatively modeled and then simulations will be performed to view the molecular interactions from spatial and dynamic points of view. Analytical models will be constructed that one could use to predict the solvation effects using well-known solute and solvent properties. This model will be used to predict experimental observations on solute diffusion, relaxation and chemical reaction rates in supercritical fluids at various temperatures and pressures. Professor Maroncelli will conduct experiments simultaneously with theoretical work. Anthracene in supercritical carbon dioxide is one chemical system being probed. This work is especially timely because of the interest in supercritical solvents for a wide variety of applications such as environmentally benign processing and remediation as well as separations and extraction. Supercritical solvation has extremely important industrial applications, and a more complete theoretical understanding of this phenomenon will have an important impact.