Heat Capacity of Saturated and Compressed Liquid Dimethyl Ether at Temperatures from (132 to 345) K and at Pressures to 35 MPa

Published

April 11, 2018

Author(s)

Joe W. Magee, Jiangtao Wu

Abstract

Molar heat capacities at constant volume (C_v) of dimethyl ether have been measured with an adiabatic calorimeter. Temperatures range from the triple point to 345 K, and pressures up to 35 MPa. Measurements were conducted on liquid in equilibrium with its vapor and on compressed liquid samples. The samples are of high purity, as verified by chemical analysis. Calorimetric quantities are reported for the two-phase (C_v(2)), saturated-liquid (C_σ or C_x'), and single-phase (C_v) molar heat capacities. Low temperature C_v(2) data were employed to estimate vapor pressures for values less than 100 kPa by applying a thermodynamic relationship between the two-phase internal energy U(2) and the temperature derivatives of the vapor pressure. Vapor pressures were calculated at temperatures as low as the triple-point temperature. The principal sources of uncertainty are the temperature rise measurement and the change-of-volume work adjustment. The expanded relative uncertainty (with a coverage factor k=2 and thus a two-standard deviation estimate) is estimated to be 0.7 % for C_v, 0.5 % for C_v(2) and 0.7 % for C_σ. Key Words: compressed liquid; dimethyl ether; heat capacity; density; vapor pressure.

Citation

Journal of Chemical and Engineering Data

Pub Type

Journals

Download Paper

https://doi.org/10.1021/acs.jced.8b00037

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Keywords

compressed liquid, dimethyl ether, heat capacity, density, vapor pressure

Citation

Magee, J. and Wu, J. (2018), Heat Capacity of Saturated and Compressed Liquid Dimethyl Ether at Temperatures from (132 to 345) K and at Pressures to 35 MPa, Journal of Chemical and Engineering Data, [online], https://doi.org/10.1021/acs.jced.8b00037, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=921772 (Accessed September 30, 2025)