光促进下环己烯与二氧化碳羰基化反应中副产物的气相色谱-质谱分析

应用气相色谱-质谱法（GC-MS）研究了光促进温和条件下环己烯与CO2羰基化反应中与丙酮有关的副产物,这有助于对反应进行深入的研究和优化。在光促进温和条件下环己烯与CO2进行羰基化反应的同时,环己烯也可以与反应体系中的CH3COCH3发生光化学反应,生成副产物。分别用CH3COCH3和CD3COCD3进行实验,对反应产物进行GC-MS分析,通过对不同反应情况下的MS图中同位素效应的比较,可以分析出副产物中是否有来自CH3COCH3中的—CH3。研究表明丙酮与底物环己烯之间生成了环氧丁烷衍生物、cyclo-C6H9-C(CH3)2OH和cyclo-C6H11-C(CH3)2OH等3种副产物。

Analysis of By-Products in Photopromoted Carbonylation of Cyclohexene and Carbon Dioxide by Gas Chromatography-Mass Spectrometry

The analysis of gas chromatography-mass spectrometry (GC-MS) has been applied more and more in organic chemistry because of the availability of the immediate information from reaction mixture. In some simple reaction systems, the structures can be determined by the comparison of the normal MS with the isotopic MS though usually it is difficult to get structures only from MS. Cyclohexene could also react with acetone to produce by-products in photopromoted carbonylation of cyclohexene with carbon dioxide under ambient conditions. CH3COCH3 and CD3COCD3 were used to analyze those by-products in the carbonylation of cyclohexene with carbon dioxide by GC-MS. The comparison of the normal MS with the isotopic MS from CH3COCH3 and CD3COCD3 was made to make sure if acetone takes part in side-reactions. The molecular weight and mass charge ratio of some related fragments could increase by 3 (one -CH3 from CH3COCH3) or 6 (two -CH3 from CH3COCH3) when using CD3COCD3 in place of CH3COCH3, which was an efficient way to determine the structures and the fragments in MS. By using this method it was confirmed that 2% derivative of epoxybutane, 4% cyclo-C6H9-C(CH3)2OH and 2% cyclo-C6H11-C(CH3)2OH were formed from the reaction of cyclohexene and acetone. The explanation of the formation of these three compounds was made according to photochemistry and the experimental results.