Azeotropes prediction by “sectionwise fitting”

✍ Scribed by A. Tamir

• Publisher: Elsevier Science
• Year: 1981
• Tongue: English
• Weight: 744 KB
• Volume: 36
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(81)80046-2

✦ Synopsis

Prediction of azeotropic behaviour of multicomponent mixtures by means of very simple equations becomes possible by applying the method of "sectionwise fitting". In this method the data set is divided into a number of sections and each section is correlated separately. Consequently, new ternary and quaternary azeotropes were detected.

INTRODUClTON

in the correlation of thermodynamic or other kinds of data, one usually strives to achieve simultaneously the following objectives: high accuracy and a minimal number of parameters in the series expansion. The latter point is particularly important, because by increasing the order of the fit, inflection points begin to appear in unexpected locations due to mathematical rather than physical significant reasons.

This phenomenon is demonstrated in Fig. 1, where the boiling points at atmospheric pressure of mixtures of tetrahydrofuranwater (111, p. 490) are plotted vs composition. As can be seen from the solid line, the mixture exhibits azeotropic ',/f \ \ \ I' /I' \ ..__d' 2'.