Vapour pressures of isobutane at T = (310 to 407) K

• Published in: The Journal of chemical thermodynamics 2004-10, Vol.36 (10), p.919-923
• Main Authors: Miyamoto, H., Takemura, J., Uematsu, M.
• Format: Article
• Language: English
• Subjects: Chemical thermodynamics; Chemistry; Elements, mineral and organic compounds; Exact sciences and technology; General and physical chemistry; Isobutane; Measurements; Thermodynamic properties; Vapour pressure
• ISSN: 0021-9614; 1096-3626
• DOI: 10.1016/j.jct.2004.06.012

Twenty-eight measurements of the vapour pressure for isobutane have been obtained by means of a metal-bellows variable volumometer at temperatures from 310 K to 407 K. The volume-fraction purity of isobutane used through the measurement was 0.9999. The expanded uncertainties ( k = 2) in temperature and pressure measurements have been estimated to be less than ±4 mK and ±1.1 kPa, respectively. The agreement of the present measurements on various volumes of the bellows at the same temperature is almost within the absolute average deviations of ±0.2 kPa. The discrepancies between two series of the present measurement, in which the sample fillings and adopted platinum resistance thermometers are different, have also been confirmed as enough lower than the experimental uncertainty. Throughout the present study, the direct comparisons of the vapour-pressure measurements on the same temperatures with several points data from the literatures were made in order to assess the reliability of the present ones quantitatively. In addition, based on the present measurements as input data, the Wagner-type vapour-pressure correlation was provided, which was also used for the systematic comparisons between the present measurement and the literature data.