Patent ID: 7847121

Claim:
A terephthalic acid production process comprising: (a) treating a concentration acidic feed stream comprising a solvent and terephthalic acid solids in a concentration zone to thereby produce a solvent rich stream and a concentrated isolation acidic feed stream comprising at least a portion of said terephthalic acid solids; and (b) isolating at least a portion of said terephthalic acid solids from at least a portion of said concentrated isolation feed stream in a product isolation zone to thereby produce a mother liquor and an isolated product comprising isolated solids, wherein said isolated solids comprise terephthalic acid particles and oxidation byproducts comprising at least one selected from the group consisting of isophthalic acid (IPA), phthalic acid (PA), trimellitic acid, 2,5,4′-tricarboxybiphenyl, 2,5,4′-tricarboxybenzophenone, 4-CBA, naphthalene dicarboxylic acid, monocarboxyfluorenones, and dicarboxyfluorenones, wherein said oxidation byproducts are formed in said terephthalic acid production process, wherein the kg/hr rate at which said oxidation byproducts exit said product isolation zone with said isolated solids and a portion of said oxidation byproducts are combined with said isolated purified terephthalic acid solids downstream of said product isolation zone is at least 15 percent of said oxidation byproducts generated in said production process; wherein said purified terephthalic acid particles are purified without the use of a hydrogenation step.