Raman spectroscopic study of cyclohexane at pressures below 1000MPa

Erwei Qiao; Haifei Zheng

doi:10.1016/j.saa.2017.05.033

Raman spectroscopic study of cyclohexane at pressures below 1000MPa

Spectrochim Acta A Mol Biomol Spectrosc. 2017 Oct 5:185:52-54. doi: 10.1016/j.saa.2017.05.033. Epub 2017 May 16.

Authors

Erwei Qiao¹, Haifei Zheng²

Affiliations

¹ Key Laboratory of Neotectonic Movement and Geohazard, Ministry of Land and Resources, Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China. Electronic address: qewzq@163.com.
² Laboratory of Orogenic Belts and Crustal Evolution, Ministry of Education, School of Earth and Space Sciences, Peking University, Beijing 100871, China.

PMID: 28535461
DOI: 10.1016/j.saa.2017.05.033

Abstract

At present, the room temperature freezing pressure of cyclohexane is still uncertain, and the phase transition pressure of solid I - solid III is not reliable at ambient temperature. In this work, we have performed a Raman spectroscopic study of cyclohexane in a Moissanite anvil cell at pressures below 1000MPa at 25°C, and analyzed the characteristic of Raman brands ν_s(CH₂), ν_as(CH₂) and ν_b(Ring). Two phase transition pressures 80MPa and 550MPa were determined by a quartz pressure gauge, and they are the room temperature freezing pressure of cyclohexane and the phase transition pressure of solid I to solid III, respectively. Furthermore, from the phase diagram of cyclohexane, it is inferred that pressure plays an important role on the stability of cyclohexane as the main constituent of oil, and it can be beneficial to understanding the formation, migration and preservation of petroleum in subterranean rock strata.

Keywords: Cyclohexane; Moissanite anvil cell; Pressure gauge; Quartz; Raman spectroscopy; Room temperature freezing pressure.