Vapor-liquid coexistence curves in the critical region and the critical temperatures and densities of difluoromethane and pentafluoroethane

Shigeo Kuwabara, Hirokazu Aoyama, Haruki Sato, Koichi Watanabe

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Abstract

The vapor-liquid coexistence curves in the critical region of difluoromethane (HFC-32) and pentafluoroethane (HFC-125) were measured by a visual observation of the meniscus in an optical cell. Seventeen saturated-liquid and 13 saturated-vapor densities have been measured in a temperature range from 330 K to the critical temperature, corresponding to a density range from 218 to 790 kg·m-3 for HFC-32. Sixteen saturated-liquid and 13 saturated-vapor densities have been measured in a temperature range from 331 K to the critical temperature, corresponding to a density range from 342 to 895 kg·m-3 for HFC-125. The experimental uncertainties of temperature and density measurements are estimated to be within ±10 mK and between ±0.10% and ±0.42%, respectively. Not only the level of the meniscus disappeared but also the intensity of the critical opalescence was considered in the determination of the critical temperature and density of HFC-32, being 351.255±0.010K and 424±1 kg·m-3, and those of HFC-125, being 339.165±0.010 K and 568±1 kg·m-3.

Original languageEnglish
Pages (from-to)112-116
Number of pages5
JournalJournal of Chemical and Engineering Data
Volume40
Issue number1
Publication statusPublished - 1995 Jan

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Vapors
Liquids
Density of gases
Temperature
Temperature measurement
pentafluoroethane
difluoromethane
3-hydroxymethylfuran-N-ethylcarbamate

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Chemistry(all)

Cite this

Vapor-liquid coexistence curves in the critical region and the critical temperatures and densities of difluoromethane and pentafluoroethane. / Kuwabara, Shigeo; Aoyama, Hirokazu; Sato, Haruki; Watanabe, Koichi.

In: Journal of Chemical and Engineering Data, Vol. 40, No. 1, 01.1995, p. 112-116.

Research output: Contribution to journalArticle

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