Polyesterification kinetic parameters

In view of the enormous number of articles and patents concerned with esterifications and polyesterifications, very few kinetic studies on these processes have been reported. In Table 3 (see page 99 to 142) are listed the main kinetic parameters published so far for linear polyesterifications and model esterifications. 

Table 3. Kinetic parameters of esterification and polyesterification reactions. - The listed values relate to the following cases Reactions where at least one of the two reactants is difunctional and reactions between two monofunctional reactants having more than 4 carbon atoms in their molecule. Table is in two parts Part 1 (page 99 to 122) for experimental conditions. Part 2 (page 122 to 142) for results and references. 

Table 5.2 Kinetic Parameters for Uncatalyzed Polyesterification of Adipic Acid with Several Glycols ...

Table 5.3 Kinetic Parameters for Some Acid Catalyzed Polyesterifications and Polamidations ...

Table 3. Kinetic parameters of epoxy-carboxy esterification and polyesterification reactions — Table is in two parts Part I (page 182 to 198 for experimental conditions. Part 2 (page 199 to 208 for results and references, r = initial molar ratio of epoxide (or diepoxide) to acid (or diacid) when r is given (third column), no solvent is present. [Al, and are acid and epoxide initial concentrations, reflectively... 

The kinetic parameters of the polyesterification were determined from literature (Beig-zadeh and Sajjadi, 1995, Chen and Hsiao, 1981, Chen and Wu, 1982, Kuo and Chen, 1989) and process data. 

Several parameters have to be taken into account in order to explain the differences in reactivity observed when using various polyamide and polyether blocks. Considering the nature of the polyether block, the nature of the functional end-group is one of the major factors influencing the polyesterification kinetics. 

Lehtonen et al. (1998) considered polyesterification of maleic acid with propylene glycol in an experimental batch reactive distillation system. There were two side reactions in addition to the main esterification reaction. The equipment consists of a 4000 ml batch reactor with a one theoretical plate distillation column and a condenser. The reactions took place in the liquid phase of the reactor. By removing the water by distillation, the reaction equilibrium was shifted to the production of more esters. The reaction temperatures were 150-190° C and the catalyst concentrations were varied between 0.01 and 0.1 mol%. The kinetic and mass transfer parameters were estimated via the experiments. These were then used to develop a full-scale dynamic process model for the system. 

The rate constants obtained by the above method for uncatalyzed polyesterification of adipic acid with different glycols are shown in Table 5.2. The Arrhenius parameters A and E of the equation k — Aexp —E/RT) are also presented in Table 5.2 for those reactions that have been studied kinetically at more than one temperature. Note that the concentration units of the rate constants are in terms of moles per kilogram, which is a more convenient measure of concentration than the usual moles per liter because the volume of the system decreases significantly due to reaction. 

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