Comments on the calculation methods of kinetics of polyesterification reactions

✍ Scribed by E. Szabó-Réthy

• Publisher: Elsevier Science
• Year: 1971
• Tongue: English
• Weight: 667 KB
• Volume: 7
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(71)90041-3

✦ Synopsis

A calculation method is presented for kinetic investigations of bifunctional polycondensation reactions which, in contrast to those described in the literature and based on Flory's theory, takes account of the water released during the polycondensation. Kinetic relations corrected for the water are given; they illustrate the role of the water in various calculation methods and its effects on the kinetic parameters. Errors of the approximate calculations are also presented. The following principal conclusions are drawn:

The rate constant calculated by Flory's equations is actually constant only for second order reactions; at higher orders, it depends on the degree of polycondensation. The error due to neglect of the condensation water is 15-20 per cent for second order reactions; in third order reactions, it rises from an initial value of 15-20 per cent up to 25-35 per cent as the degree of polycondensation increases.

In contrast to Flory's method, the rate constants calculated from kinetic equations using approximate degrees of polycondensation are equal to their corrected values but the degrees of polycondensation differ from the actual values. These differences are also dependent on the degree of polycondensation; the resulting error reaches about 25 per cent.