Acenaphthylene, absorption

Figure 3 depicts profiles of Total PAH fluxes vs. time (36). The following polycyclic hydrocarbons have been determined by high performance liquid chromatography, variable wavelength absorption detection Naphthalene, acenaphthylene, 7,12-dimethylbenzanthracene, 2-methylnaphtalene, fluorene, acenaphtene, phenanthrene, 2,3-dimethylnaphtalene, anthracene, fluoranthene, 1-methylphenanthrene, pyrene, 2,3-benzofluorene, triphenylene, benz(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, perylene, benzo(e)pyrene, 1,2,3,4-dibenzanthracene, benzo(a)pyrene, and 1,2,5,6-dibenzanthracene. 

Bromine-atom atomic resonance absorption spectrometry (ARAS) has been applied to measure the thermal decomposition rate constants of CF3Br in Kr over the temperature range 1222-1624 K. The results were found to be consistent with recently published theory. The formation of cyclopent[a]indene and acenaphthylene from alkyl esters of biphenyl-mono- and -di-carboxylic acids has been observed in flash vacuum pyrolyses at 1000-1100 °C. The kinetics and mechanisms of free-radical generation in the ternary system containing styrene epoxide, / -TsOH, and i-PrOH have been examined in both the presence and absence of O2. ... 

Two analytical methods for priority pollutants specified by the USEPA (38) use HPLC separation and fluorescence or electrochemical detection. Method 605, 40 CFR Part 136, determines benzidine and 3,3-dichlorobenzidine by amperometric detection at +0.80 V, versus a silver/silver chloride reference electrode, at a glassy carbon electrode. Separation is achieved with a 1 1 (v/v) mixture of acetonitrile and a pH 4.7 acetate buffer (1 M) under isocratic conditions on an ethyl-bonded reversed-phase column. Lower limits of detection are reported to be 0.05 /xg/L for benzidine and 0.1 /xg/L for 3,3-dichlorobenzidine. Method 610, 40 CFR Part 136, determines 16 PAHs by either GC or HPLC. The HPLC method is required when all 16 PAHs need to be individually determined. The GC method, which uses a packed column, cannot adequately individually resolve all 16 PAHs. The method specifies gradient elution of the PAHs from a reversed-phase analytical column and fluorescence detection with an excitation wavelength of 280 nm and an emission wavelength of 389 nm for all but three PAHs naphthalene, acenaphthylene, and acenaphthene. As a result of weak fluorescence, these three PAHs are detected with greater sensitivity by UV-absorption detection at 254 nm. Thus, the method requires that fluores-... 

Figure 3.9. Magnetic circular dichroism (top) and absorption polarized along the z axis (—) and along the y axis (—) of a) acenaphthylene and b) pleiadiene (by permission from Kolc and Michl, 1976, and from Thulstrup and Michl, 1976).

Figure 3.9 shows the MCD spectra of acenaphthylene and pleiadiene. The second and the third absorption bands overlap strongly. They are the N, or L, and N2 or L2 bands, which differ in the sign of the B term and are therefore easy to recognize in the MCD spectra. For comparison the linearly polarized spectra, obtained from measurements on stretched sheets, are also shown. They also make it possible to distinguish the two bands, since they have different polarization directions. 

Only light PAHs (2 or 3 rings) are soluble in water at the mgL-1 level. Figure 41 shows UV spectra of acenaphthylene in water and in acetonitrile. The shape of the two spectra is similar, and no solvent effect is observed on the absorption wavelengths. Consequently, all PAH UV spectra have been acquired in acetonitrile solutions. 

The importance of light absorption to directly populate the triplet state in the presence of heavy atoms [(10.271)] and the effect of heavy atoms on the phosphorescence of acenaphthylene [(10.27m)] are easily ruled out. No new absorption bands or increased band intensities are noted in the presence of heavy atoms. Since no phosphorescence is observed, even at low temperature, there cannot be an important effect on this process. A heavy-atom effect on the partitioning of reactions (10.27g,h) and (10.27k) is eliminated by the data of Hartmann, Hartmann, and Schenck in their study of solvent effects on the photosensitized photolysis of acenaphthylene. The influence of a number of solvents was described with the use of Kirkwood-Onsager solvent parameters (an empirical method for the correlation of reaction rate with the ability of the solvent to stabilize the change in dipole moment in proceeding to the transition state). A linear plot of log(fra/u/cw) vs. the expression [(Z) — 1)/(2Z) -f- where D is the dielectric constant, p is... 

Studied using nanosecond laser flash photolysis. It is reported that two reaction pathways are possible electron transfer or nucleophilic addition when thermodynamically feasible, the electron-transfer pathway dominates. The electronic absorption spectrum of the radical cation (25) has been obtained by y-irradiation of 6b,7,8,8a-tetrahydrocyclobut[a] acenaphthylene in a CFCI3—CF2BrCF2Br matrix at 77 At >640 nm, this is converted into an isomer (26) which is the same as the radical cation obtained by ionization and irradiation of l,4-dihydro-l,4-ethanonaphtho[l,8-de][l,2]diazepine (27) at >540 nm. The electronic absorption spectra of aU the radical... 

Studies of dietary uptake of PAHs in fish generally indicate low uptake efficiency. In their study of dietary absorption in rainbow trout [Oncorhyn-chus mykiss (Salmo gairdneri)] fed trout diet, Niimi and Dookhran (1989) found dietary absorption of PAHs ranging from 2% to 32% for compounds such as phenylnaphthalene, acenaphthylene, methylanthracene, tri-phenylene, and perylene. The lower absorption efficiencies occurred when... 

Samanta, A., Devadoss, C., and Fessenden, R.W., Picosecond time-resolved absorption and emission studies of the singlet excited states of acenaphthylene, /. Phys. Chem., 94,7106, 1990. Dunsbach, R. and Schmidt, R., Photophysical properties of some polycyclic conjugated hydrocarbons containing five-membered rings, /. Photochem. Photobiol. A Chem., 83, 7, 1994. 

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