Abstract:

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.

Key words: acetone, by-products , carbon dioxide, carbonylation, cyclohexene, deuterated acetone, gas chromatography-mass spectrometry