Sedimentary environment indicators: Benzothiazole and its derivatives

Abstract

Benzothiazoles distributional characteristics of crude oils and non-hydrocarbon fractions of source rocks in Mangya depression of the Qaidam Basin, Lunnan oil field in the Tarim Basin, Kelamayi oil field in the Junggar Basin and the Tulufan Basin oil field were analyzed. It was found that the distributions of benzothiazole are remarkable diversity in different sedimentary environmental oils. The swamp crude oils contain high quantity of benzothiazole and relatively high quantity of alkylthio-benzothiazole and 2(3H)-benzothiazolone. But the quantity of the 2,2 '-dithiobisbenzothiazole is relatively low. The abundance of benzothiazole and 2,2 '-dithiobis-benzothiazole are relatively high in semi-brackish water lacustrine crude oils, but the quantity of alkylthio-benzothiazole and 2(3H)-benzothiazolone are relatively low. The benzothiazoles belong to weak acid and mild base compound, and their stabilization conditions relate to their environmental medium. The nitrogenous bases are in favor of alkalescence environment, while weak acid nitrogenous compounds are the main stable products under the weak acid environment. Benzothiazoles have great significance in identifying the oil-and gas-formed environment and the geochemistry study of non-hydrocarbon fraction in the future.

Transformation of Benzothiazole in Estuarine Sediments

“…A range of heteroarene compounds containing nitrogen, sulfur, and oxygen are found in natural sediments and water, and at elevated levels near industrial activities, urban centers, and waste sites (Warshawsky, 1992; Bieko et al, 1987; Catallo et al, 1990; Turov et al, 1987; Furlong and Carpenter, 1982; Krone et al, 1986; Thompkins and Ho, 1982; Malins et al, 1985; Chou and Bohonos, 1979; Smith et al, 1977, 1978; Catallo, 1996). Benzothiazole (BT, I, CAS #95‐16‐9) is found in a broad range of natural and synthetic mixtures (Bieko et al, 1987; Catallo, 1996; Reddy and Quinn, 1997; Li et al, 2001; Seo et al, 2002; Reemtsma et al, 2002; Bellavia et al, 2000; Lopez et al, 1999; Tale, 2002; Kashiyama et al, 1999; Jaycox and Olsen, 2000; Chien et al, 2003; Kumata et al, 2000).…”

“…Benzothiazole (Fig. 1) and several of its derivatives occur in crude oils and other geochemical mixtures (Catallo, 1996; Li et al, 2001). Other BT derivatives are biologically active and of interest in pharmacology and cancer biology (Kashiyama et al, 1999).…”

“…The purpose of this work was to study BT in estuarine sediments under realistic electrochemical and hydrologic conditions and to resolve and identify to some degree the product mixtures resulting from biogeochemical transformation of BT. Both goals are germane to the use of BT and its homologs as anthropogenic (Kumata et al, 2000) or natural (Li et al, 2001) geochemical markers, remediation of BT in wastewater and slurries, and the significance of exotic products from chemical and biotransformation of BT.…”