Patent ID: 7161027
Filing Date: 2007-01-09
Classification: C07C

Abstract:
1. A process to produce a purified carboxylic acid composition said process comprising: (a) removing impurities from a crude carboxylic acid slurry composition in a solid liquid displacement zone to form a slurry composition; (b) oxidizing said slurry composition at a temperature of about 190° C. to about 280° C. in a staged oxidation zone to form a staged oxidation composition; (c) crystallizing said staged oxidation composition in a crystallization zone to form a crystallized composition; (d) removing in a subsequent solid liquid displacement zone impurities from said crystallized composition to form a purified carboxylic acid slurry composition; wherein said impurities comprise 4-carboxybenzaldehyde, trimellitic acid, or 2,6-dicarboxyfluorenone; wherein said subsequent solid liquid displacement zone comprises a solid liquid separator that is operated at a temperature between 110° C. and 200° C.; (e) cooling said purified carboxylic acid slurry composition in a cooling zone to form a cooled purified carboxylic acid slurry composition; and (f) filtering and drying said cooled purified carboxylic slurry composition in a filtration and drying zone to remove a portion of the solvent from said cooled purified carboxylic acid slurry composition to produce said purified carboxylic acid composition.