2002 Fiscal Year Final Research Report Summary
Studies on Characteristic Properties of Supercritical Fluids from the View Point of Fluctuation
| Project/Area Number |
13440173
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Physical chemistry
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| Research Institution | Chiba University |
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Principal Investigator |
NISHIKAWA Keiko Chiba University, Graduate School of Science and technology, Professor, 大学院・自然科学研究科, 教授 (60080470)
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| Co-Investigator(Kenkyū-buntansha) |
MORITA Takeshi Faculty of Engineering, Tokyo University, Agriculture and Technology, Research Associate, 工学部, 助手 (80332633)
SAITOW Ken-ichi Chiba University, Graduate School of Science and technology, Research Associate, 大学院・自然科学研究科, 助手 (80302579)
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| Project Period (FY) |
2001 – 2002
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| Keywords | supercritical fluids / supercritical solutions / fluctuation / small-angle X-ray scattering / Raman scattering / dynamic light scattering / active region / swelling |
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| Research Abstract |
Supercritical fluids are characterized by large inhomogeneity of molecular distribution. The density fluctuation is a suitable parameter for quantitative and direct description of the inhomogeneity. We have comprehensively investigated the density fluctuation of several kinds of supercritical fluids by means of small-angle X-ray scattering (SAXS) experiments and have found the following facts. .
(i)The density fluctuation forms a ridge when the contour map of their values is drawn in a phase diagram. (ii)The ridge corresponds to extrema of the various physical quantities of supercritical fluids, which are related to the second derivatives of the Gibbs free energy. (iii)The rate of increase in solubility becomes maximum on the ridge. Namely, the ridge separates the supercritical region into two, regions, in which the solubility is extremely different, (iv) The rate constants or equilibrium constants of various chemical reactions in supercritical fluids show singular behaviors on the ridge. It is concluded that the density fluctuation is one of the most fundamental factors which determine properties of supercritical fluids and its ridge is the boundary which separates, the supercritical region into two.
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