Chrysene temperature

Reported aqueous solubilities of chrysene at various temperatures and reported temperature dependence equations... 

Logarithm of mole fraction solubility (In x) versus reciprocal temperature for chrysene. 

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). 

Under atmospheric conditions, a low rank coal (0.5-1 mm particle size) from Spain was burned in a fluidized bed reactor at seven different temperatures (50 °C increments) beginning at 650 °C. The combustion experiment was also conducted at different amounts of excess oxygen (5 to 40%) and different flow rates (700 to 1,100 L/h). At 20% excess oxygen and a flow rate of 860 L/h, the amount of chrysene emitted ranged from 127.9 ng/kg at 950 °C to 1,186.0 ng/kg at 750 °C. The greatest amount of PAHs emitted were observed at 750 °C (Mastral et ah, 1999). 

Preannihilative electrochemical oxidation of the phenanthrene anion has given a green emission13,64 spectrally nearly identical to the previously reported room-temperature phenanthrene phosphorescence which is a single broad peak.71 Chemical oxidation of the chrysene anion with Wurster s blue perchlorate produced an emission containing three bands at 19,800, 18,600, and 17,400 cm"1 which seem to correspond to the known phosphorescence bands of chrysene (19,500,18,500, and 16,600 cm-1). Chemical oxidation of the radical anion of N-methylcarbazole has possibly led to phosphorescent emission from this triarylamine.7... 

PAHs also generally have well-structured emission spectra (see Figs. 10.6-10.10) and relatively large fluorescence quantum yields. For example, in degassed n-heptane at room temperature, the fluorescence quantum yields are as follows fluoranthene, 0.35 benz[ ]anthracene, 0.23 chrysene, 0.18 BaP, 0.60 BeP, 0.11 and benzo[g/zi]perylene, 0.29 (Heinrich and Giisten,1980). Cyclopenta[crf]pyrene, however, does not fluoresce. 

The solubility of compounds in water changes as the temperature/pressure are increased. The solubility of anthracene, pyrene, chrysene, perylene, and carbazole were determined at temperatures ranging from 298 K to 498 K and pressures from 30 bar to 60 bar in snbcritical (snperheated) water. Increasing temperature up to 498 K increased solnbihties by 5 orders of magnitnde. While large increases in pressnre resnlt in lower solnbihties, over the narrow range of pressnres studied, pressure had a minimal effect (Miller et al., 1998). 

Kinetic data on the oxepin-benzene oxide equilibration have been obtained from the temperature-dependent NMR studies. Low values were observed for the enthalpy of isomerization of oxepin (7.1 kJ mol-1) and 2-methyloxepin (1.7 kJ mol-1) to the corresponding benzene oxides (67AG(E)385). The relatively small increase in entropy associated with oxepin formation (5-11 J K 1 mol-1) is as anticipated for a boat conformation in a rapid state of ring inversion. Thermal racemization studies of chrysene 1,2- and 3,4-oxides have allowed accurate thermodynamic parameters for the oxepin-arene oxide equilibration process in the PAH series to be obtained (81CC838). The results obtained from racemization of the 1,2- (Ea 103.7 kJ mol-1, AS 3.7 JK-1 mol-1 and 3,4- (Ea 105.3 kJmoF1, AS 0.7 J K"1 mol ) arene oxides of chrysene are as anticipated for the intermediacy of the oxepins (31) and (32) respectively. 

Figure 2. Gas chromatogram of A, PAH fraction of diesel particulate extract (Sl-C2) and By its HPLC subfraction C (S1-C2). GC conditions 45- X 0.35-mm id SE54 glass capillary column flame ionization detector temperature, 110°C for 2 min, programmed to 170°C at 10°/min, to 212°C at 3°/min, to 278°C at 8°/min. Peak identities 1, phenanthrene 2, anthracene 3-6, methylanthracene/-phenan-threne 7, 2-phenylnaphthalene 8-10, dimethylanthracene/-phenanthrene 11, fluoranthene 12, aceanthrylene/acephenanthrylene 13, pyrene 14-15, trimethylan-thracene/-phenanthrene 16, benzo [ghi]fluoranthene 17, benzo[a/anthracene 18, triphenylene 19, chrysene 20, benzo[b]fluoranthene 21, benzo[]]fluoranthene ...

Epoxidation of aromatic hydrocarbons is an important method for the preparation of arene oxides. m-Chloroperbenzoic acid (MCPBA) is used in a two-phase system that involves treating the hydrocarbon with a large excess ( 10-fold) of MCPBA in methylene chloride-aqueous sodium bicarbonate at room temperature. The yields are moderate (10-60%). Because the arene oxides are sensitive to acids, the presence of sodium bicarbonate buffer is necessary. A number of K-region (see Section VII for a definition) epoxides like phenanthrene 9,10-oxide (1, 59%), 9,10-dimethylphenanthrene 9,10-oxide (2,40%), 9-phenylphenanthrene 9,10-epoxide (3,50%), pyrene 4,5-oxide (4, 14%), and chrysene 4,5-oxide (5,9%) have been prepared by this method.9... 

The use of elevated temperature at the beginning of this reaction leads to the formation of chrysenes, as described in Section IlI,F,2,b. 

Probably, the experimental conditions (temperature and solvent) determine the conversions of 2-benzopyrylium salts 266 into the chrysene derivatives 270 via a-1 dimerization or [4 + 2] cycloaddition (Scheme 14) (89TH2). 

Thus, dimer 276 is obtained from salt 30 at room temperature in a diphase system of 10% aqueous solution of sodium hydroxide and ether. On heating with alkali in isopropyl alcohol, these dimers are converted quantitatively into benz[a]anthracenes 278 (88KGS1185), and likewise the formation of dihydro-derivatives of chrysenes 271 (85KGS910) and 277... 

At the 95% confidence interval, no significance in terms of the three operating parameters was found when considering the total polycyclic aromatic hydrocarbon recovery. However, recoveries of some individual polycyclic aromatic hydrocarbons were found to be dependent on operating variables. In particular, low operating temperatures of 40 °C were very significant for naphthalene, chrysene and benzo(b)fluoranthene. 

Figure 11 contains the experimental data for chrysene (5) replotted as Ink versus temperature with the solid line being the theoretical prediction of the slope from eq. 22. The data in Figures 10 and 11 are both with n-pentane as the fluid mobile phase the difference between the two sets of data is the experimental pressure. The model predicts the trend in retention for both cases quite well. In Figure 11 one can see the decrease in importance of the volume expansivity and heat capacity of the fluid on retention as the experimental conditions are further removed from the critical temperature and pressure of the fluid. 

The hydrogenation of chrysene over a 10% Pd-C catalyst at room temperature and 0.31 MPa H2 afforded 5,6-dihydrochrysene, while over platinum oxide 1,2,3,4-tetra-hydrochrysene was formed as the major product along with several minor products. 1,2,3,4,5,6-Hexahydrochrysene was obtained in 42% yield in the hydrogenation over a mixed Pd-C/platinum oxide under similar conditions (Scheme 11.25).270... 

Irradiation of anthracene and chrysene in natural water by UV and sunlight has been reported to be first-order at low concentrations [20]. Photolysis rate and reaction efficiencies for anthracene and chrysene were highly dependent on oxygen concentration and increased as the temperature was raised [20]. 

Another transformation of one aromatic compound to another is the Stone-Wales rearrangement of pyracyclene (113), which is a bond-switching reaction. The rearrangement of bifluorenylidene (114) to dibenzo[g,p] chrysene (115) occurs at temperatures as low as 400° C and is accelerated in the presence of decomposing iodomethane, a convenient source of methyl radicals. This result suggested a... 

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