Patent ID: 7074954

Claim:
A process to produce a purified carboxylic acid slurry 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 190Â° C. to about 280Â° 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; and (d) removing in a subsequent solid liquid displacement zone impurities from said crystallized composition to from said purified carboxylic acid slurry composition; wherein said impurities comprise 4-carboxybenzaldehyde, trimellitic acid, or 2,6-dicarboxyfluorenone; and wherein said subsequent solid liquid displacement zone comprises at least one solid liquid separator that is operated at a temperature between 110Â° C. to 200Â° C.