Separation and determination of impurities in terephthalic acid

Abstract

An anion exchange chromatographic procedure has been presented for the determination of small concentrations of trimesic acid(TMA), p-toluic acid(PTA), and p-carboxyl benzyl alcohol (PCBA) in terephthalic acid(TPA).
In the separation of TMA and TPA, the sample is placed on an Amberlite IR-45 (R-Cl, 100200 mesh) column of 175 mm in length and 8 mm in diameter, and the elution is carried out with a methanolic solution of NaCl containing5030% water.
PTA, PCBA, and TPA are separated from each other by the stepwise elution with a methanolic solution of NaCl containing 3070% water. The acids in each effluent are determined by u. v. spectrophotometry.
From 0.8 to 2% of TMA or PTA in TPA can be determined by this method within a deviation of 0.1%.