Abstract
The organic impurities are formed in the p-xylene oxidation process to terephthalic acid(TPA) and they are present in the filtrate(mother liquor) solution or the TPA particles. The organic impurities present in the p-xylene oxidation are formed through side reactions or incomplete reaction. In this study, the main organic impurities, such as benzoic acid, p-toluic acid, p-tolualdehyde, 4-carboxybenzaldehyde, phthalic acid, isophthalic acid, trimellitic acid, and 4-hydroxymethyl benzoic acid were identified simultaneously by gas chromatograghy. The above impurities were reacted with bis(trimethylsilyl)trifluoroacetamide in the mixture of internal standard solution and pyridine solution by trimethylsilylation, where the internal standard solution was made by 99% bis (trimethylsilyl)trifluoroacetamide and 1% trimethylchlorosilane. The main organic impurities above mentioned can be analyzed quantitatively within 50 min.
파라자일렌(p-xylene)을 산화반응시켜 테레프탈산(terephthatic acid)을 제조하는 과정 중에 발생하는 주요 유기불순물을 효과적으로 분석하는 방법을 수립하였다. 이 제조공정 중에 발생하는 유기불순물은 매우 다양하나, 여기에서는 주로 benzoic acid, p-toluic acid, p-tolualdehyde, 4-carboxybenzaldehyde, phthalic acid, isophthalic acid, trimellitic acid와 4-hydroxymethyl benzoic acid 등의 유기불순물을 분석하는데 촛점을 맞추었다. 이 유기물들은 공정 중의 모액이나 고체상태의 테레프탈산 입자에 존재하는데, 이들을 동시에 분석하기 위해 99% bis(trimethylsilyl)trifluoroacetamide와 1% trimethylchlorosilane의 내부표준용액과 pyridine의 혼합용액내에서 trimethylsilylation으로 시료를 전처리하고 gas chromatography를 이용하여 분석한 결과 상기한 유기물이 모두 성공적으로 분리되어 50분 이내에 정량분석할 수 있었다.