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Raman studies of solvent- and solute-molecule states in supercritical fluids

超临界流体中溶剂和溶质分子状态的拉曼研究

基本信息

批准号：
12640502
负责人：
ISHII Kikujiro
金额：
$ 2.24万
依托单位：
Gakushuin University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12640502/
关键词：
supercritical fluids solvation Raman scattering ラマン散乱

项目摘要

This work aimed at studying simultaneously the molecular states of both the solvent and solute in supercritical fluids by Raman spectroscopy for the better understanding of solvation in multi-components supercritical fluids. In the first year, we constructed the high-pressure system and improved the optical system. In the second year, we checked the performance of these systems in detail and carried out Raman studies on CO_2/benzene and CO_2/chlorobenzene binary samples.As to the operation condition of the high-pressure system, we concluded that the following manner is the best for realizing desired sample conditions. Namely, we first introduce into the Raman cell, at a constant temperature and a constant pressure, the solvent and solute fluids with a given flow rates. When the concentration of the solute was established after a certain period, we close the inlet and outlet of the cell during the Raman measurement. After this we repeat the measurement by reducing the cell pressure every time by releasing the content in the cell through the outlet.By the analysis of the preliminary measurements, we have obtained the following results, (a) We can obtain Raman spectra with sufficient quality even for the sample with 0.01 mole fraction of the solute, (b) With a CO_2/benzene sample of the 1:0.1 flow-rate ratio, we found additional Raman bands which appear in the gas-like region of the supercritical state. These bands are considered to be attributed the complex molecule between CO_2 and benzene, are worth being studied further in detail, c With a CO_2/chlorobenzene sample of the 2:0.01 flow-rate ratio, we found a remarkable shift and bandwidth change of the chlorobenzene bands, which is considered to indicate the specific interaction between solute molecules with dipole moment and CO_2.

为了更好地理解多组分超临界流体中的溶剂化作用，本文利用拉曼光谱技术同时研究了超临界流体中溶剂和溶质的分子状态。在第一年，我们建造了高压系统并改进了光学系统。第二年，我们对这些系统的性能进行了详细的测试，并对CO_2/苯和CO_2/氯苯二元样品进行了拉曼光谱研究，对于高压系统的操作条件，我们得出如下结论：即，我们首先在恒定温度和恒定压力下将具有给定流速的溶剂和溶质流体引入到拉曼池中。当在一定时间后确定溶质浓度时，我们在拉曼测量期间关闭池的入口和出口。通过对初步测量结果的分析，我们得到了以下结果，（a）即使对于溶质摩尔分数为0.01的样品，我们也可以获得足够质量的拉曼光谱，（B）对于溶质摩尔分数为1：0.1的流量比，我们发现额外的拉曼带出现在气体的超临界状态的区域。这些谱带被认为是CO_2与苯之间的络合物分子，值得进一步研究。在流速比为2：0.01的CO_2/氯苯样品中，我们发现氯苯谱带发生了显著的位移和带宽变化，这被认为是具有偶极矩的溶质分子与CO_2之间的特异性相互作用。