| Project/Area Number |
16350006
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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 Chiba University, Graduate School of Science and Technology, Assistant, 大学院・自然科学研究科, 助手 (80332633)
齋藤 健一 千葉大学, 理学部, 助手 (80302579)
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| Project Period (FY) |
2004 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥15,400,000 (Direct Cost: ¥15,400,000)
Fiscal Year 2005: ¥5,800,000 (Direct Cost: ¥5,800,000)
Fiscal Year 2004: ¥9,600,000 (Direct Cost: ¥9,600,000)
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| Keywords | Supercritical fluids / Supercritical aqueous solution / Hydrogen bonding / Density fluctuation / Concentration fluctuation / Small-angle X-ray Scattering / Near infra-red spectrum / Raman scattering / 水和構造 |
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| Research Abstract |
Experimental data by small-angle X-ray scattering (SAXS) give us the most information on the structural fluctuation of sub-critical and supercritical aqueous solutions. Extended X-ray absorption fine structure (EXAFS) experiments are suitable to obtain the information of structure in microscopic scale. We developed a sample holder applicable to both SAXS and EXAFS experiments.
We have started the experiments to elucidate the concentration fluctuations of supercritical solutions, which give us information on mixing scheme of the solutions. In this project, we studied the following three systems.
1) Sub-critical CH_3OH-H_2O
Comparing the results with those of ambient conditions, it has been shown that the density fluctuation increases significantly with the rise in temperature and pressure, whereas concentration fluctuation remains unchanged. Namely, it is concluded that the hydrogen bonding networks are similar in ambient and sub-critical state of the mixture.
2) Supercritical Xe-Kr
3) Supercritical CO_2-CHF_3
In studies 2) and 3), we developed the methodology to obtain partial molar volumes and isothermal compressibility of supercritical solutions. Using these data in addition to the SAXS data, we can obtain the concentration fluctuation of the solutions.
We have also developed a spectrometer for near infra-red absorption, which is suitable to elucidate the forms of hydrogen bonding. We have applied this apparatuse to some ambient aqueous solutions and sub-critical water.
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