Terpane

Terne plate bundles Terne steel Terpal Terpane... 

By oxidation with potassium permanganate, terpinenol yields trioxy-terpane, Cj,, -(OH)3, melting at 114° to 116°, and by boiling with dilute sulphuric acid carvenone results. This body yields a semi-carbazone, melting at 202°. 

Boeda et al. (1996) identified bitumen on a flint scraper and a Levallois flake, discovered in Mousterian levels (about 40 000 BP) at the site of Umm el Tlel in Syria. The occurrence of polyaromatic hydrocarbons such as fluoranthene, pyrene, phenanthrenes and chrysenes suggested that the raw bitumen had been subjected to high temperature. The distribution of the sterane and terpane biomarkers in the bitumen did not correspond to the well-known bitumen occurrences in these areas. In other studies of bitumen associated with a wide variety of artefacts of later date, especially from the 6th Millennium BC onwards, molecular and isotopic methods have proved successful in recognizing different sources of bitumen enabling trade routes to be determined through time (Connan et al., 1992 Connan and Deschesne, 1996 Connan, 1999 Harrell and Lewan, 2002). 

Seifirt, W. K. and Moldowan, J. M., 1979, Applications of Steranes, Terpanes and Monoaromatics to the Maturation, Migration and Source of Crude Oils Geochemica et Cosmo-chimica Acta, Vol. 42, No. 1, pp. 77-95. 

Tricyclic terpanes (Structure IV, Fig. 1), usually ranging from C19H34 to C30H56, and in some cases to C45H86 [68,124-126]... 

Tetracyclic terpanes C24-Tetracyclic (17,21 -seco-hopane) C24H42 330... 

Novel biomarkers, i.e. tracer derivatives from unknown natural products, are sometimes encountered in geological or environmental samples, typically as hydrocarbons. The detection and determination of these compounds are usually based on the interpretation of mass spectra in GC-MS analyses. The proofs of chemical structures are based on the proposed interpretation of the MS data, separation and purification of the unknown compounds, exact structure determination by NMR methods or X-ray crystallography (if the compound is a solid that can be crystallized), and finally, comparison with a synthetic standard. The next question concerns the biological source of the biomarker precursor compound. Many biomarkers still have no proven natural product precursors nor known biological sources (e.g. perylene, tricyclic terpanes). " ... 

Aquino Neto FR, Restle A, Connan J, Albrecht P, Ourisson G, Novel tricyclic terpanes (Cig, C20) in sediments and petroleums. Tetrahedron Letters 23 2027-2030, 1982. 

Simoneit BRT, Leif RN, Radler de Aquino Neto F, Almeida Azevedo D, Pinto AC, Albrecht P, On the presence of tricyclic terpane hydrocarbons in Permian tasmanite algae, Naturwissenschaften 77 380-383, 1990. 

Figure 5 Partial ion chromatogram of the terpanes (mfz 191) from the modem, Chersh Meghir, bitumen seep sample. Key to peak identification is shown in...

Reduction of the bicyclic sulfides with Raney nickel yielded a homologous series of monocyclic terpanes as illustrated by the example of the C13 member Q, ) ... 

Figure 14 shows the C27 and the C29-C32 terpane m/e 191 mass chromatographic profiles for the five coals. Their mass spectra match those of the hopane series found abundant in Messel shale (6). The C27 and C29-C30 hopanes were confirmed by coinjection with the authentic hopanes. Note the decrease in relative concentration with the maturity of the 17- H C27, C29, and C30 hopanes (7). This is further confirmation of the thought that the 17-y3H hopanes are thermodynamically less stable than the 17- H, 21- H series. The ratios of the 17-/3H series to the 17-aH series may be reliable indicators of the maturity of a deposit. This may be complicated by the chance that the relative intensities within a series may carry some information about environmental conditions at the time of formation of a deposit. 

There are two observations to be made here. The relative concentration of the sesquiterpanes to the pentacyclic diterpanes decreases with the maturity of the coal. The relative concentration of total terpane to aromatics also decreases with the maturity of the coals. 

The Yl-fiH, 21-ySH hopane concentrations relative to the 17-aH isomer appear to be very sensitive indicators of the rate of maturation of sediments. The total terpane concentration changes from 1.1% in Noonan lignite to about 0.4% in the Loveridge coal. 

Terpanes and steranes, as well as their partially aromatized counterparts, cadalene, and copaene released from nonvolatile insolubles in coal and kerogen from shales by pyrolysis are contamination-free biomarkers that carry information concerning their geochemical history. 

Figure 6 GCMS is a widely used technique in petroleum exploration and production studies. The use of multiple ion detection to obtain the fingerprints for the various classes of biomarkers is an extremely important ancillary GCMS technique. In this diagram the miz 191 and 217 chromatograms show the distributions of the terpanes and...

Compounds such as steranes and terpanes in cmde oils are referred to as biomarkers. The biomarker concept was developed by Eglinton and Calvin (1967), who recognized the presence... 

Figure 7 The concentrations of individual biomarkers in a crude oil are relatively low but the complex nature of their structures means their information content is high. This diagram provides an indication of the approximate concentrations of individual steranes and terpanes in a t)fpical cmde oil.

Seifert W. K. (1978) Steranes and terpanes in kerogen pyrolysis for correlation of oils and source rocks. Geochim. Cosmo-chim. Acta 42, 473 -484. 

Seifert W. K. and Moldowan J. M. (1978) Applications of steranes, terpanes and monoaromatics to the maturation, migration and source of crude oils. Geochim. Cosmochim. Acta 42, 77 -95. 

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