对二甲苯低温氧化工艺的固体残渣成分分析

Composition analysis of solid residues from p-xylene low-temperature oxidation process

采用高效液相色谱、气相色谱、气质联用仪与紫外分光光度计对低温氧化工艺的固体残渣的成分进行了定性和定量分析。结果表明:过滤残渣中约90%为对苯二甲酸,脱色后即可回收利用;萃取残渣中主要是苯甲酸、对甲基苯甲酸、间苯二甲酸。2种残渣中可回收的对苯二甲酸占75%左右。有色杂质的主要成分是芴酮酸、二苯环羧酸和蒽醌酸类,对产品色度影响最大的是蒽醌酸,其次是芴酮酸和二苯环羧酸。按照芴酮-4-羧酸的吸光度计算的过滤残渣中有色杂质总浓度为10^(-3)量级。

The composition of solid residues from p -xylene low-temperature oxidation was anlayzed qualitatively and quantitatively by high-efficiency liquid-phase chromatography, gas-phase chromatography, gas-phase chromatography and gas chromatography-mass spectrography. The results showed that terephthalic acid accounted for about 90% in the.filtration residue, which can be recycled after decoloration ; and the extraction residue dominantly comprised benzoic acid, p -toluic acid and isophthalic acid. About 75% of these two residues was the recoverable terephthafic acid. The coloured residues dominantly included anthraquinone dicarboxylic acid, flurenone dicarboxylic acid and dibenzyl carboxylic acid, among which anthraquinone dicarboxylic acid offered the most remarkable effect on the product color index and flurenone dicarboxylic acid and dibenzyl carboxylie acid took the second place. The concentration of coloured imputrities in the filtration residue reached a magnitude of 10^-3, characterized by flurenone- 4-carboxylic acid spectrophotometry absorbance.