Analysis of long-side-chain alkylaromatics in crude oil for evaluation of their fate in the environment.
It has long been believed that the n-hexane fraction of crude oil only contains saturates. However, we found that one-third of its content was aromatics with long alkyl side chains and that these aromatics could be separated from the saturates by preparative thin-layer chromatography. The separated alkylaromatic fraction was characterized by UV-visible, NMR and mass spectrometries. A gas chromatographic-mass spectrometric analysis showed the presence of a homologous series of long-side-chain n-alkylaromatics, namely mono-, di-, and tri-n-alkylbenzenes in the C7-C27 range (the subscript to C indicates the total number of carbon atoms in the alkyl side chain) and di- and tri-n-alkylbenzothiophenes in the C3-C22 range. The biodegradation of these crude oil components by a natural bacterial population in seawater and their photooxidation by artificial sunlight were investigated. The n-alkylbenzenes were found to be quite susceptible to biodegradation but resistant to photooxidation, whereas the n-alkylbenzothiophenes were almost completely photooxidized and substantially biodegraded.
Dutta
T K
TK
Marine Biotechnology Institute, Kamaishi, Iwate, Japan.
Harayama
S
S
D001419:Bacteria / Q000378:metabolism; D001673:Biodegradation, Environmental; D002850:Chromatography, Gel; D004785:Environmental Pollutants / Q000032:analysis* / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D006841:Hydrocarbons, Aromatic / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D010084:Oxidation-Reduction; D010578:Petroleum / Q000032:analysis* / Q000378:metabolism; D010777:Photochemistry; D012623:Seawater / Q000382:microbiology
D004785:Environmental Pollutants; D006841:Hydrocarbons, Aromatic; D010578:Petroleum