己内酰胺成品中挥发性碱杂质的研究

通过GC-MS定性分析己内酰胺成品重结晶后的杂质浓缩液，比较不同质量等级己内酰胺的杂质差异，特别是影响挥发性碱含量的杂质。结果表明，己内酰胺成品中主要含有C3 C7直链酰胺、肟、苯胺和己二酰亚胺等杂质，其中C3 C7直链酰胺和己二酰亚胺对挥发性碱含量影响最大，其含量增加0.1 mmol/kg，挥发性碱含量约上升0.1 mmol/kg；苯胺对挥发性碱含量影响较小，肟及环状内酰胺基本无影响。与优级品相比，己内酰胺合格品中主要含有较多C3 C7直链酰胺及己二酰亚胺、一级品含有微量的正戊酰胺和正己酰胺而使挥发性碱含量超标。

(NO.S208013).AN ANALYSIS OF IMPURITIES AFFECTING THE VOLATILE BASE CONTENT IN CAPROLACTAM

The compositions of impurities in the concentrated mother liquids after the recrystallizations of three various quality grades caprolactam products were analyzed by GC-MS to compare the impurities that affect the volatile base contents in these products. Results showed that the impurities were mainly composed of C3-C7 amides with straight chain, C6 imides, oximes and aniline, in which C3-C7 amides with straight chain and C6 imides had significant effect on the volatile base content: with the increase of 0.1 mmol/kg these impurities, the volatile base content could increase 0.1 mmol/kg. Aniline had less effect on the volatile base content; oximes and lactams had little effect. As compared with the superior caprolactam product, in the qualified product impurities were mainly composed of C3-C7 amides with straight chain and C6 imides, in the first-class product minor impurities were n-valeramide and n-caproamide, however, the existence of these impurities in products leads to a higher volatile base content, which degrades the product class.