Comparative high pressure Raman studies on perfluorohexane and perfluoroheptane
C Kavitha1, Chandrabhas Narayana2
1Department of Chemistry - R&D Center, BMSIT, Affiliated by VTU, Avalahalli, Yelahanka, Bangalore, Karnataka, India.
Summary
High pressure studies reveal distinct phase transitions in perfluorohexane and perfluoroheptane. Perfluoroheptane exhibits more complex transitions, suggesting conformational changes under pressure.
Area of Science:
- Materials Science
- Physical Chemistry
- Spectroscopy
Background:
- Perfluorocarbons are widely used in various industrial applications.
- Understanding their behavior under extreme conditions is crucial for material design.
- Previous studies on perfluorocarbons under pressure are limited.
Purpose of the Study:
- To investigate the pressure-induced phase transitions of perfluorohexane and perfluoroheptane.
- To analyze conformational changes in these molecules at high pressures.
- To elucidate the structural properties of perfluorocarbons under compression.
Main Methods:
- High-pressure Raman spectroscopy was employed.
- Experiments were conducted up to 12 GPa.
- Spectra were analyzed to identify phase transitions and conformational changes.
Main Results:
- Perfluorohexane showed two transitions: liquid-solid at 1.6 GPa and solid-solid at 8.2 GPa.
- Perfluoroheptane exhibited three transitions: liquid-solid at 1.3 GPa, solid I at 3 GPa, and solid II at 7 GPa.
- Analysis of Raman spectra suggested conformational changes, including gauche to trans conversion in perfluoroheptane, and close packing with distorted all-trans conformers at high pressures.
Conclusions:
- Perfluorohexane and perfluoroheptane display unique pressure-induced phase behaviors.
- Perfluoroheptane's transitions indicate complex conformational rearrangements under pressure.
- High-pressure phases favor close packing with distorted all-trans conformers for both compounds.
Keywords:
Gauche defectHigh pressurePerfluorocarbonsPhase transitionsRaman scatteringTrans-conformationMore Related Videos
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