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Abstract

Since Andrews' discovery in 1869, that gases could be liquified only if the temperature was below some critical value, the determination of critical constants and understanding of how properties vary near the critical point have received great attention. The situation often arises, however, that properties at the critical point are required for a particular substance where only limited low temperature data are available. Indeed, it is unlikely that static experiments will ever reach the temperatures required to investigate the critical region of most metals ( degrees 3000 K). Transient heating techniques, although capable of producing the very high temperatures required, are complicated to analyse and have relatively large errors associated with temperature measurement. Hence it is of great value to be able to make an estimate of the required property from the known behaviour of other substances. These estimation procedures can be broadly classified into three types based on empirical correlation of experimental data, the Van-der-Waals equation of state, and the principle of corresponding states. Many empirical correlation have been proposed from studies of mainly hydrocarbons and simple non-polar and slightly polar substances. Those which are applicable, however, such as the modified Guldberg rule and the law of rectilinear diameters, have been made use of extensively in the literature and provide some of the best estimates of the critical constants available.

Additional information

Authors: MAGILL J, JRC KARLSRUHE ESTAB. (GERMANY);OHSE R W JRC KARLSRUHE ESTAB. (GERMANY), JRC KARLSRUHE ESTAB. (GERMANY)
Bibliographic Reference: PUBLISHED IN HANDBOOK OF THERMODYNAMIC AND TRANSPORT PROPERTIES OF ALKALI METALS, 1985, CHAPTER 1.5.1, PP. 73 - 103.
Record Number: 1989124085900 / Last updated on: 1987-01-01
Category: PUBLICATION
Available languages: en