An experimental investigation of n-hexane at high temperature and pressure

Erwei Qiao; Haifei Zheng

doi:10.1016/j.saa.2018.05.093

An experimental investigation of n-hexane at high temperature and pressure

Spectrochim Acta A Mol Biomol Spectrosc. 2018 Oct 5:203:210-213. doi: 10.1016/j.saa.2018.05.093. Epub 2018 May 28.

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: 29870904
DOI: 10.1016/j.saa.2018.05.093

Abstract

At present, no high temperature experiments on phase change are reported. In this study, we have measured the Raman bands ν_s(CH₃), ν_s(CH₂), ν_as(CH₃), and ν_as(CH₂) of n-hexane in a hydrothermal diamond cell up to 588 K. We determined that the liquid-solid phase transition pressure of n-hexane is 1.17 GPa, and we also gave a number of high temperatures and pressures data on phase change which are not reported previously. In addition, we defined the solidus of n-hexane which can be represented by the equation P = 8.581T-1550.16, and the relation dP/dT = 8.581 which can be used to calculate the thermodynamic parameters for n-hexane in the liquid-solid phase transition. For all we know, the above two equations are presented here for the first time. Furthermore, it is the first report here in a graphic way on high-temperature phase change in n-hexane, and it is also the first to be shown in the 3-D figure.

Keywords: High temperature; Hydrothermal diamond anvil cell; Phase diagram; Raman spectroscopy; Thermodynamic parameter; n-Hexane.