Polyaromatic hydrocarbons chrysene

Fig. 34.3. UV-visible spectra of two polyaromatic hydrocarbons (PAHs), fluoranthene and chrysene.

Figure 5.12 Polyaromatic hydrocarbon species (1) phenanthrene, (2) anthracene, (3) pyrene, (4) benz[o]anthracene, (5) chrysene, (6) naphthacene, (7) benzo[c]phenanthrene, (8) benzo[ghi] fluoranthene, (9) dibenzo[c,g]phenanthrene, (10) benzo[g/ ]perylene, (11) triphenylene, (12) o-terphenyl, (13) m-terphenyl, (14) p-terphenyl, (15) benzo[o]pyrene, (16) tetrabenzonaphthalene, (17) phenanthro[3,4-c]phenanthrene, (18) coronene...

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). 

Hankin et al. [46] have used spacially residued time of flight mass spectrometry for quantification studies on polyaromatic hydrocarbons. Deuterated polyaromatic hydrocarbons were used as internal standards, chrysene-d being adopted in the final method. Theoretical values were obtained bj this procedure on standard reference soils. 

Many polycyclic aromatic amines and aldehydes are commercially available, but their supply is very limited. Preparation of these starting materials is necessary for studying the (3-lactam formation reaction [93]. Nitro compounds are the precursors for the amines. An important task was to prepare polycyclic aromatic nitro compounds, particularly those of chrysene, phenanthrene, pyrene, and dibenzofluorene in good yield. Nitration of these hydrocarbons with concentrated nitric acid in sulfuric acid is a widely used reaction for this purpose. Our research culminated in facile synthesis of polyaromatic nitro derivative 9 starting from polyaromatic hydrocarbons (PAHs) 8 through the use of bismuth nitrate impregnated with clay (Scheme 1) ([94, 95] for some examples of bismuth nitrate-catalyzed reactions... 

Fig. 4.4.10. Separation of a polyaromatic hydrocarbon mixture on 5 different brands of chemically bonded ODS-silica, the carbon content of the individual materials are given in brackets, a, HC-ODS (8.5%) b, LiChrosorb RP-18 (19.8%) c, Partisil-10 ODS-2 (16%) d, Zorbax ODS (10%) e, pBondapak C,g (10%). Peaks 4, benz[a]anthracene 5, chrysene 6, benzo[e]pyrene 7, benzo b]fluoroanthrene 8, benzo k]fIuoroanthrene 11, benzo[ghi]perylene 12, indeno[l,2,3-c,d]pyrene. Reprinted from Ref. 14 with permission.

Two intramolecular substitutional arylation reactions are catalyzed by Pd(0) and lead to the spherical polyaromatic hydrocarbon 3.616. X-ray diffraction study of 3.616 showed significant distortions in the structure. Such bowl-shaped polycyclic aromatic hydrocarbons are the building blocks for preparing fullerene structures [162, 291]. The first syntheses of the fullerene precursors were carried out by vacuum pyrolysis. Corannulene 3.617, diindeno[l,2,3,4-d /g l, 2, 3, 4 -mnop]chrysene 3.618, and semibuckminsterfullerene 3.619 were obtained, which creates a basis for the development of the synthesis of Cgo molecules (Figure 3.5) [300, 162]. 

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