| Abstract
| - It has long been believed that the n-hexane fraction ofcrude oil only contains saturates. However, we found that one-third of its content was aromatics with long alkyl sidechains and that these aromatics could be separated fromthe saturates by preparative thin-layer chromatography.The separated alkylaromatic fraction was characterized byUV−visible, NMR and mass spectrometries. A gaschromatographic-mass spectrometric analysis showed thepresence of a homologous series of long-side-chainn-alkylaromatics, namely mono-, di-, and tri-n-alkylbenzenesin the C7−C27 range (the subscript to C indicates thetotal number of carbon atoms in the alkyl side chain) anddi- and tri-n-alkylbenzothiophenes in the C3−C22 range.The biodegradation of these crude oil components by anatural bacterial population in seawater and theirphotooxidation by artificial sunlight were investigated. Then-alkylbenzenes were found to be quite susceptible tobiodegradation but resistant to photooxidation, whereasthe n-alkylbenzothiophenes were almost completelyphotooxidized and substantially biodegraded.
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