Ester-interchange between esters and glycols

The more precisely kinetic aspects of transesterification are divided into two sections in the following pages ester-interchange between esters and glycols, and the polycondensation reaction. The latter is subdivided into sections on uncatalysed and catalysed polycondensation. 

Fontana also reinterpreted some earlier data [63], and suggested the existence of a reversible dissociation reaction 

This interpretation was recently shown to be erroneous [66]. No evidence exists for the reversible dissociation, though there is little doubt that at elevated temperatures ester linkages can cleave to form carboxylic acid end-groups and vinyl esters (Section 5.2). 

Neglecting catalyst concentration, then, the transesterification reaction between esters and glycols appears to be of the second order, with the rate proportional to ester and glycol concentrations. 

In the case of polycarbonates, Turska and Wrobel [67] showed that the transesterification reaction between bisphenol A and diphenyl carbonate was third order, including a term for catalyst, when the reaction was carried out above 230°C. Below 230°C there were anomalous results. 

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