己内酰胺联产工艺中影响成品290nm处吸光度杂质的定性定量分析

Qualitative and Quantitative Analysis of Impurities in the Products of Combined Caprolactam Process,Affecting Absorbency at 290 nm

利用气相色谱-质谱联用技术对环己烷羧酸-环己酮肟联产己内酰胺工艺中影响成品在290 nm处的吸光度的杂质进行了定性分析。分析结果表明,联产工艺生产的己内酰胺中含有八氢吩嗪。利用紫外分光光度法证实了八氢吩嗪的含量与290 nm处的吸光度存在近似线性的相关性,因而推断八氢吩嗪为影响产品在290 nm处吸光度的主要杂质。反应机理的研究结果表明,八氢吩嗪是由环己酮肟Beckmann重排过程局部硫酸量不足,环己酮肟硫酸酯发生Neber重排形成的连氮化合物衍生而成。建立了八氢吩嗪的高效液相色谱分析方法,较优的分析条件为:C18色谱柱(4.6 mm×250 mm×5μm),流动相为体积比为30:70的乙腈-水溶液,流量1.0 mL/min,紫外检测器检测波长290 nm。该方法具有准确、快速和简单的优点。

An impurity, which affected the absorbency at 290 nm in the ultraviolet spectro- photometry, in the caprolactam products synthesized from cyclohexanecarboxylic acid and cyclohexanone oxime was analyzed by means of was octahydrophenazine. The linear correlativity was GC-MS. The results showed that it found between the concentration of octahydrophenazine and the absorbency at 290 nm. It was indicated that the octahydrophenazine derived from Neber rearrangement products which existed in the Beckmann rearrangement of cyclohexanone oxime when the system lacked sulfuric acid. The octahydrophenazine was analyzed quantificationally by means of HPLC and the optimal conditions were obtained as follows： C18 chromatographic column（4.6 mm× 250 mm×5μm）, acetonitrile and water（volume ratio 30 ： 70） as mobile phase with a flow rate of 1.0 mL/min and detection wavelength of the ultraviolet spectrophotometry 290 nm. This method was proved to have the advantages of precise, rapidity and simplicity.