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Liquid-Phase Speed of Sound and Vapor-Phase Density of Difluoromethane



Aaron Rowane, Elizabeth Rasmussen, Mark O. McLinden


Difluoromethane (HFC-32, DFM), with a global warming potential (GWP) of 677, is of interest as a pure refrigerant and as a component in low-GWP refrigerant mixtures. Additionally, difluoromethane has recently been identified as a safe, liquefied-gas electrolyte material in batteries. Using state-of-the-art instruments for measurements, this paper presents new liquid-phase speed of sound and vapor-phase density data for difluoromethane. Two hundred and nine liquid-phase speed of sound values were measured using a dual-path pulse-echo instrument at temperatures from 230 to 345 K and pressures from 2.1 to 70 MPa. Accounting for all sources of uncertainty, the relative expanded combined uncertainty (k = 2) in the speed of sound ranged from 0.035 to 0.17%. One hundred and thirty-eight vaporphase density values were measured using a two-sinker densimeter at temperatures from 240 to 340 K and pressures from 0.1 to 1.61 MPa with an uncertainty of 0.011 to 0.12%. These experimental data will be valuable in the ongoing development of a new fundamental thermodynamic equation of state for difluoromethane.
Journal of Chemical and Engineering Data


Rowane, A. , Rasmussen, E. and McLinden, M. (2022), Liquid-Phase Speed of Sound and Vapor-Phase Density of Difluoromethane, Journal of Chemical and Engineering Data, [online],, (Accessed April 21, 2024)
Created September 23, 2022, Updated November 29, 2022