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Spectroscopic Study of Water-Hydrocarbon Mixtures at High Temperatures and Pressures.

高温高压下水-烃混合物的光谱研究。

基本信息

批准号：
13440169
负责人：
IKAWA Shun-ichi
金额：
$ 8.13万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

项目摘要

We have elucidated the following properties of mixed fluids at high temperatures and pressures.(1) Water concentration in a hydrocarbon-rich phase initially increases dramatically as temperature rises at constant pressure, and reach maximum at a temperature close to one-phase critical curve, and then steeply decreases at higher temperatures.(2) Water molecules in benzene and alkylbenzene at temperatures below 523K exist as monomers or dimers, and the relative ratio of the dimers increases with increasing temperature.(3) π-hydrogen bonding interaction between water and a benzene ring exists even at high temperatures under pressure.(4) An anomalously large volume expansion occurs on mixing of water and hydrocarbons in a certain temperature-pressure range. This finding could be observed for the first time by the in situ infrared measurements of the fluid mixtures. For water-benzene mixtures, the volume expansion is particularly large in the region enclosed by (a) the gas-liquid equilibrium curve of water, (b) an extended line of the three-phase equilibrium curve, and (c) the one-phase critical curve of the mixtures.(5) Solubility of benzene in water is an order of magnitude smaller than that of water in benzene, and the solubility of benzene in water increases with increasing pressure at constant temperature, while that of water in benzene decreases. This asymmetry of the mutual solubilities can be understood by differences in molecular size and in isothermal compressibility between water and benzene.(6) For high-temperature-pressure water, it is found that (i) in the compressed gas or gas-like condition a monomer-dimer equilibrium exists and the dimerization enthalpy is estimated to be (-15±3)kJ/mol, (ii) an appreciable proportion of water molecules rotate quite freely even at 673K at 400 bar, and (iii) ratio of hydrogen bond formation is dependent on molar density irrespective of temperature.

我们阐明了混合流体在高温高压下的以下性质。(1)在恒压条件下，富烃相中的水浓度最初随着温度的升高而急剧增加，在接近一相临界曲线的温度处达到最大值，然后在较高温度下急剧下降。(2)温度低于523K时，苯和烷基苯中的水分子以单体形式存在 (3)水与苯环之间即使在高温、高压下也存在π-氢键相互作用。(4)水与烃类在一定温度-压力范围内混合时会发生异常大的体积膨胀。这一发现可以通过流体混合物的原位红外测量首次观察到。对于水-苯混合物，在(a)水的气液平衡曲线、(b)三相平衡曲线的延长线和(c)混合物的单相临界曲线围成的区域中体积膨胀特别大。 (5)苯在水中的溶解度比水在苯中的溶解度小一个数量级，苯在水中的溶解度在恒温条件下，随着压力的增加而增加，而苯中的水则减少。这种相互溶解度的不对称性可以通过水和苯之间的分子大小和等温压缩性的差异来理解。(6)对于高温高压水，发现(i)在压缩气体或类气体条件下存在单体-二聚体平衡，并且二聚热函估计为(-15±3)kJ/mol，(ii)相当大的比例即使在 673K、400 bar 的温度下，水分子的旋转也相当自由，并且 (iii) 氢键形成的比率取决于摩尔密度，与温度无关。