Excess molar volumes and densities of (methanol+water) at temperatures between 323 K and 573 K and pressures of 7.0 MPa and 13.5 MPa
β Scribed by Caibin Xiao; Hugo Bianchi; Peter R. Tremaine
- Publisher
- Elsevier Science
- Year
- 1997
- Tongue
- English
- Weight
- 483 KB
- Volume
- 29
- Category
- Article
- ISSN
- 0021-9614
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β¦ Synopsis
Densities of {xCH3OH + (1x)H2O} relative to water were measured in a vibrating-tube densimeter at the temperatures (323, 373, 423, 473, 523, and 573) K and at pressures of 7.0 MPa and 13.5 MPa. Excess molar volumes V E m for {xCH3OH + (1x)H2O} were calculated from the experimental densities for the mixtures, using accurate equations of state for water and methanol. The data were treated with a modified corresponding-states model based on the properties of pure water. An empirical function was used to fit small differences between the compression factors of {xCH3OH + (1x)H2O} and the compression factor of H2O at the same reduced temperature and the same reduced pressure. The corresponding-states treatment reproduces the measured densities to within the experimental uncertainty of 0.4 kgβ’m -3 at all of the temperatures and pressures studied, except at T = 573 K and p = 13.5 MPa. The densities, excess molar volumes, partial molar volumes, isothermal compressions, and cubic expansion coefficients from the model are consistent with the limited literature data available. The behaviour of V E m at T = 573.6 K and p = 13.7 MPa indicates either a very narrow region of (vapour + liquid) phase separation, or near-critical behaviour at x 1 0.44 with the critical pressure pc E 13.5 MPa.
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