Patent ID: 7741516

Claim:
A process to produce an enriched composition suitable for use as a monomer stream in a step-growth polymerization process, said process comprising contacting an enrichment feed with at least one stream comprising terephthalic acid, wherein said at least one stream is obtained after all oxidation steps in a terephthalic acid (TPA) production process to form said enriched composition; wherein said enrichment feed comprises at least one compound selected from the group consisting of isophthalic acid, phthalic acid, benzene-tricarboxylic acid isomers, hydroxybenzoic acid isomers, hydroxymethylbenzoic acid isomers, dicarboxybiphenyl isomers, dicarboxystilbene isomers, tricarboxybiphenyl isomers, tricarboxybenzophenone isomers, dicarboxybenzophenone isomers, dicarboxybenzil isomers, form-acet-hydroxybenzoic acid isomers, acet-hydroxymethylbenzoic acid isomers, and phthaldehyde isomers; wherein said enriched composition is enriched in at least one of said compound relative to said at least one stream.