Abstract: Disclosed is a method for purifying aromatic dicarboxylic acid such as isophthalic acid or terephthalic acid. The process treats a crude carboxylic acid (CCA) composition by: A. feeding a CCA composition comprising a liquid and a solid, said liquid comprising an organic solvent and said solids comprising dicarboxylic acid (DCA), to a filter cake formation zone to form: (i) a CCA wet cake composition comprising said DCA solids and a portion of said organic solvent, said CCA wet cake composition having a first liquid level; and (ii) a first mother liquor stream; B. dewatering said CCA wet cake composition to form: (i) a dewatered CCA wet cake composition having a second liquid level that is lower than the first liquid level or having no liquid level; and (ii) a second mother liquor stream; and C. washing the dewatered CCA wet cake composition with a wash stream in a wash zone to form: (i) a washed CCA wet cake composition; and (ii) a wash liquor stream; wherein step B is performed before step C.

Abstract: The invention relates to a process for purifying and decolorizing a phenyl ester salt. The process combines a phenyl ester salt with a solvent to form a mixture and then stirs the mixture to form a slurry. The phenyl ester salt is substantially insoluble in this solvent. The process then collects the phenyl ester salt from the slurry. The collected phenyl ester salt may then be optionally dried or recrystallized. The collected phenyl ester salt is dissolved in a solvent to form a solution. The solution is decolorized and then spray dried to form a powder of the phenyl ester salt. As a result of the process the phenyl ester salt powder has a higher purity and an improved color as compared to the starting phenyl ester salt.

Abstract: The invention relates to a process for purifying and decolorizing a phenyl ester salt. The process combines a phenyl ester salt with a solvent to form a mixture and then stirs the mixture to form a slurry. The phenyl ester salt is substantially insoluble in this solvent. The process then collects the phenyl ester salt from the slurry. The collected phenyl ester salt may then be optionally dried or recrystallized. The collected phenyl ester salt is dissolved in a solvent to form a solution. The solution is decolorized and then spray dried to form a powder of the phenyl ester salt. As a result of the process the phenyl ester salt powder has a higher purity and an improved color as compared to the starting phenyl ester salt.