An experimental evaluation of the expanding core model using disproportionation of the potassium benzoate to potassium terephthalate reaction system

Abstract

ESCA, NMR and chemical analysis methods have been employed to study the disproportionation of potassium benzoate to potassium terephthalate, a reaction of industrial potential for the manufacture of polyester fibres. The experimental results have been reported in terms of variations in K/C, O/C and Cd/C ratios across pellets reacted to different extents of conversion. Data have been obtained for pellets with different initial compaction pressures and for different reaction temperatures and pressures. The results in general corroborate the earlier finding of the reaction starting at the centre, and give additional information regarding surface migration of the catalyst species (Cd). The earlier delayed diffusion model has been modified in the light of this observation and seems to predict the experimentally observed trends quite well.