甲苯法己内酰胺中290nm吸光值的杂质分析

Determination of impurities in caprolactam from toluene at 290 nm adsorption value

利用VP-ODS 250 mm×4.6 mm液相色谱柱,流动相为乙腈/水(体积比12/88),1.25 mmol/L磷酸调节酸度,流速1 mL/m in,建立了甲苯法生产的己内酰胺(CPL)中影响290 nm吸光值的杂质的高效液相色谱分析方法。采用大孔径离子树脂和活性炭吸附富集这些微量的杂质,通过液相色谱-质谱联用(LC-MS)和气相色谱-质谱联用(GC-MS)对杂质进行了定性分析。结果表明:该方法稳定可靠,可用于CPL杂质含量控制。LC-MS和GC-MS分析表明,CPL中影响290 nm的吸光值的主要杂质为苯甲腈、2-甲基-8-羟基喹啉、2,6-二氨基吡啶、邻-乙基环己酮肟和相对分子质量为220的物质。

The high-performance liquid-phase chromatography was established for determining the impurities affecting the absorption value at 290 mn during caprolactam production from toluene. The method was conducted using the VP-ODS liquid-phase chromatographic column 250 mm × 4.6 mm, acetonitrile/water （ volumn ratio 12/88 ） as mobile phase, 1.25 mmol/1 phosphoric acid for regulating the acidity and flow rate 1 mL/min. The trace impurities were adsorpted and accumulated with maeropore ion resin and activated carbon and were analyzed qualitatively by liquid chromatography-mass spectrometry （LC-MS） and gas chro- matography-mass spectrometry （GC-MS）. The results showed that the method was stable and reliable and can be used to control the impurities content of CPL. The LC-MS and GC-MS results showed that the dominating impurities affecting the absorption value of CPL at 290 nm included benzonitrile ,2-methyl-8-hydroxyquinoline, 2,6-diaminopyridine, o-ethyloxime cyclohexanone and the chemicals with the relative molecular weight mass of 220.