Gas chromatographic determination of aromatic carboxylic acids - in major and trace amts. esp. in terephthalic acid or fibre mfr.

摘要

Aromatic mono- and di- carboxylic acids are determined, after esterification, by a gas -chromatographic method on a selective column material contg. 0.5-15% polyethylene glycol, 5-15% of a polar silicone oil and 0.1-5% of an organic alkali salt, operated isothermally at 150-200 degrees C. The method is partic. suitable for qualitative and quantitative examination of pure terephthalic acid used for fibre mfr., and of the intermediate prod. dimethyl terephthalate. Other acids determined include benzoic, phenylacetic, o- and p-toluyl, phthalic, isophthalic, di-, tetra- and hexa-hydrotenrephthalic acids, and 2- and 4-carboxybenzaldehydes, eiter as major components or at impurity (50 p.p.m.) levels.