Aramids side reactions

Aramides are prepared by polycondensation using the Schotten-Baumann reaction. This reaction, which uses the selected isomers of phthaloyl chloride and phenylenediamine (or its chlorohydrate), is carried out at low temperature (from 0°C to -40°C) in order to avoid side reactions it is carried out in an amide solution (dimethylacetamide, A-methylpyrrolidone, tetramethylurea, etc.) to which mineral salts are added. 

The reactive aramid compound III, bisesteramide, was synthesized by reacting p-phenylenediamine with terephthaloyl chloride, and then with alcohols, e.g., methanol (Scheme 6) [66,67] in the absence of catalysts and acid scavengers. Since side reactions were involved, generating oligomeric products, the removal... 

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