烷基苯生产中循环烷烃的液固吸附色谱预分离和气相色谱/质谱分析

 利用 10 0目～ 2 0 0目的硅胶 ,选择正戊烷和二氯甲烷作为洗脱剂 ,采用吸附色谱法将烷基苯生产中的循环烷烃分离为饱和烃 (烷烃 +环烷烃 )及芳烃两部分。然后将饱和烃及芳烃分别进行色谱 /质谱 (GC/MS)联用分析 ,得到了有关循环烷烃构成的定性定量结果。定性结果如实地反映出烷基苯生产中的副反应产物 ,可直接用于指导生产。从定量结果可以看出 ,经过硅胶吸附分离后 ,试样中含量要求很低的芳烃被浓缩 ,提高了分析的准确度和灵敏度 ,可以检测出循环烷烃中含量很低的物质 ,为全面分析样品组成提供了有力的证据。

Liquid-Solid Adsorption Separation and Gas Chromatography/ Mass Spectrometry Analysis of Recycle Alkanes in the Production of Alkyl Benzenes

A method for qualitative and quantitative analysis of recycle alkanes in the production of alkyl benzenes is proposed in this paper The mixture was separated into saturated hydrocarbons (alkanes and cyclanes) and aromatics by means of adsorption chromatography with silica gel of 100 mesh 200 mesh as stationary phase and n pentane and dichloromethane as eluents Results were obtained by analysing these two fractions separately A total of 21 different kinds of n , iso , cyclo and a few light aromatic hydrocarbons were identified in the saturated hydrocarbons which were 97 3% of the mixture, while the rest 2 4% aromatic hydrocarbons included 15 different kinds of indanes, naphthanes and diphenylanes, the majority of which were products of dehydrogenation and alkylation, and the minor part was from original alkanes By products can be truely revealed by the qualitative analysis, which can be used to improve the process conditions Analysis showed that after adsorption separation by silica gel, the low content aromatic hydrocarbons was concentrated, and thus the analysis accuracy and sensitivity were improved. Preseparation avoided the problems which would appear if the samples were directly analysed by gas chromatography or gas chromatography/mass spectrometry.