Thermodynamic and Spectroscopic Studies of Levitated Microdroplets of Highly Supersaturated Solutions

高度过饱和溶液悬浮微滴的热力学和光谱研究

• 批准号: 9625178
• 负责人: Allan Myerson
• 金额: --
• 依托单位: Polytechnic University of New York
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-12-01 至 2000-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9625178&HistoricalAwards=false
• 关键词: Thermodynamic; Spectroscopic; Studies; Levitated; Microdroplets

ABSTRACT CTS-9625178 Allan Myerson The project examines the behavior of supersaturated solutions which must be formed prior to crystallization. Crystallization from solution is an important separation process which is used in a wide variety of industries. In this project, the solvent activity of supersaturated aqueous solutions of electrolytes (such as potassium chloride, potassium aluminum sulfate and ammonium sulfate) and aqueous and non aqueous solutions of non-electrolytes (such as glycine, adipic acid and succine acid) will be measured employing electrodynamically levitated solution microdroplets. The use of this technique removes the container walls and most dust and dirt from the solution so that very high supersaturation can be achieved. This will allow determination of the thermodynamic properties of supersaturated solutions over a wide range approaching the spinodal. In addition, Raman spectroscopy will be used to examine the formation and time evolution of subcritical molecular clusters. Appropriate theoretical treatments of the thermodynamic and spectroscopic date will be developed and used to calculate the nucleation induction time, size distribution of clusters and metastable limit boundaries. The study of the thermodynamics properties and cluster evolution in supersaturated solutions is quite difficult because these solutions are hard to prepare and keep stable. The technique of levitated microdroplets provides a unique method to prepare highly supersaturated solutions which can be examined employing Raman spectroscopy. Raman spectra of highly supersaturated solutions should yield important information on the time evolution of molecular clusters in supersaturated solutions prior to nucleation. In addition, these will be the first studies of thermodynamic and spectroscopic properties of supersaturated solutions of non-aqueous solutions. This project will supply additional data on the thermodynamic properties of supersaturated solutions of industrially important systems thus allowing modeling of the nucleation and crystal growth of these systems making use of the thermodynamic supersaturation (supersaturation based on activity instead of concentration). For cases in which the supersaturation is above 10%, it has been shown that the error in using supersaturated based on concentration is significant and increases rapidly with increasing supersaturation. In addition the work will supply fundamental data on the formation of subcritical clusters prior to nucleation through spectroscopic measurements. Using appropriate theory, this data will allow calculation of properties which are important to the industrial practice of crystallization and will aid in the design and development of crystallization processes. ***

摘要CTS-9625178 Allan Myerson该项目研究了必须在结晶之前形成的过饱和解决方案的行为。解决方案的结晶是一个重要的分离过程，用于多种行业。在这个项目中，电解质过饱和水溶液的溶剂活性（例如氯化钾，硫酸钾和硫酸铵）以及非电解质的水溶液和非水溶液的水溶液（例如甘氨酸，脂肪酸，脂肪酸和辅助溶液）的溶液将使用溶解度。这种技术的使用清除了溶液中的容器墙以及大多数灰尘和污垢，从而可以实现非常高的过饱和度。这将允许在接近旋转的范围内确定过饱和溶液的热力学特性。另外，拉曼光谱法将用于检查亚临界分子簇的形成和时间演化。将开发热力学和光谱日期的适当理论处理，并用于计算成核诱导时间，簇的尺寸分布以及可稳态的极限边界。过饱和溶液中热力学特性和簇演化的研究非常困难，因为这些溶液很难准备和保持稳定。悬浮的微螺旋体的技术提供了一种独特的方法来制备高度过饱和溶液，可以使用拉曼光谱检查进行检查。高度过饱和溶液的拉曼光谱应产生有关成核之前过饱和溶液中分子簇的时间演变的重要信息。另外，这些将是非水溶液过饱和溶液的热力学和光谱特性的首次研究。该项目将提供有关工业重要系统过饱和溶液的热力学特性的其他数据，从而允许对这些系统的成核和晶体生长进行建模，从而利用热力学过饱和（基于活性而不是浓度的过饱和）。对于过饱和超过10％的情况，已经表明，基于浓度过饱和的过饱和的错误是显着的，并且随着过饱和度的增加而迅速增加。此外，这项工作将通过光谱测量来提供有关在成核之前形成亚临界簇的基本数据。使用适当的理论，该数据将允许计算对结晶工业实践重要的属性，并有助于结晶过程的设计和开发。 ***