利用拉曼光谱技术研究亚临界水中4-氯甲苯及2,4-二氯氟苯的溶解度

发布时间：2018-07-14 21:34

【摘要】：有机物的溶解度数据是超临界流体中物质分离与纯化、配方筛选、工业应用与过程设计等的关键性参数,随着超临界流体得到日益关注和应用,物质在超临界流体中的相平衡研究和溶解度数据也得到了人们的广泛重视。然而,由于超临界流体高温高压苛刻的实验条件,获取准确的溶解度数据十分困难。传统用于测定溶解度数据的静态法取样过程中易破坏达到的相平衡,而动态法则难于保证体系已达到相平衡且溶质易于流失,基于以上原因超/亚临界水中含氯有机物溶解度数据十分缺乏。利用课题组自主设计搭建的一套测定亚临界水中疏水性有机物溶解度数据的装置对亚临界水中4-氯甲苯及2,4-二氯氟苯的溶解度进行了研究。实验过程中对冷热台温度进行了连续的校准和检验,并对亚临界水中4-氯甲苯及2,4-二氯氟苯的稳定性进行了研究。除采用拉曼光谱技术对石英毛细管反应器内溶液体系的扩散均匀度进行原位在线分析外,还对体系温度升高溶质扩散过程中溶质,溶剂(水)及纯水进行了原位拉曼光谱分析。实验结果表明:亚临界水中4-氯甲苯和2,4-二氯氟苯基本没有发生氧化水解等反应;石英毛细管内溶质-水体系经过较长时间的恒温后各处的溶质扩散均匀,不存在明显的浓度梯度;实验基于对亚临界水中4-氯甲苯和2,4-二氯氟苯相态变化实时观测的基础上分别获得了4-氯甲苯在262.3-293.8℃、2,4-二氯氟苯257.6-286.7℃温度范围内亚临界水中的溶解度数据,对数据进行拟合后得到的溶解度方程分别为S=2.13109T-528.52、S=1.34338T-302.10。研究结果表明,随温度的升高亚临界水中4-氯甲苯、2,4-二氯氟苯的溶解度数据呈线性增加。
[Abstract]:The solubility data of organic compounds are the key parameters for the separation and purification of substances in supercritical fluids, formula screening, industrial applications and process design, etc. With the increasing attention and application of supercritical fluids, The study of phase equilibrium and solubility data of substance in supercritical fluid has been paid more and more attention. However, due to the harsh experimental conditions of supercritical fluid at high temperature and high pressure, it is very difficult to obtain accurate solubility data. The traditional static sampling method used to measure solubility data is easy to destroy the phase equilibrium, while the dynamic rule is difficult to ensure that the system has reached phase equilibrium and solute is easy to lose. Based on the above reasons, the solubility data of chlorinated organic compounds in supercritical / subcritical water are very scarce. The solubility of 4-chlorotoluene and 2-trichloro-4-dichlorobenzene in subcritical water was studied by a set of apparatus designed by our research group to determine the solubility of hydrophobic organic compounds in subcritical water. During the experiment, the temperature of the cooling and hot table was continuously calibrated and tested, and the stability of 4-chlorotoluene and 2O4-dichlorofluorobenzene in subcritical water was studied. In addition to the in-situ on-line analysis of the dispersion uniformity of the solution system in a quartz capillary reactor by Raman spectroscopy, the solute, solvent (water) and pure water during solute diffusion at elevated temperature were also analyzed by in-situ Raman spectroscopy. The experimental results show that there is basically no oxidative hydrolysis reaction between 4-chlorotoluene and 2o _ 4-dichlorofluorobenzene in subcritical water, and solute diffusion in the solute water system in quartz capillary is uniform after a long time of constant temperature. There is no obvious concentration gradient. The solubility data of 4-chlorotoluene in subcritical water at 262.3-293.8 鈩，

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