Phenanthrene constant

Figure 6.10. Rate constants for quenching of sensitizers by cis- and trans-stilbenes (open and filled circles, respectively). Sensitizers are as follows (1) tri-phenylene, (2) thioxanthone, (3) phenanthrene, (4) 2-acetonaphthone, (3) 1-naphthyl phenyl ketone, (6) crysene, (7) fluorenone, (8) 1,2,5,6-dibenzanthracene, (9) benzil, (10) 1,2,3,4-dibenzanthracene, (11) pyrene, (12) 1,2-benzanthracene, (13) benzanthrone, (14) 3-acetyl pyrene, (15) acridine, (16) 9,10-dimethyl-l,2-benzanthracene, (17) anthracene, (18) 3,4-benzpyrene.<57> Reprinted by permission of the American Chemical Society.

Sediment reduction t,/2(est.) = 1196 h, t,/2(exptl) = 825 h for chemical available phenanthrene and tA = 151 h for bioavailable phenanthrene for amphipod, P. hoyi in Lake Michigan sediments at 4°C. The average uptake clearance from sediment was (0.041 + 0.023)g of dry sediment-g-1 of organism-h-1, and the rate constants to become biologically unavailable was (0.0055 0.003) h-1 resulting a bioavailable t,/2 = 126 h (Landrum 1989) desorption t,/2 = 8.6 d from sediment under conditions mimicking marine disposal (Zhang et al. 2000). 

Reported Henry s law constants and octanol-air partition coefficients of phenanthrene at various temperatures and temperature dependence equations... 

Fig. 10 Composition and spatial distribution of the main patterns of contamination identified in sediment of the Ebro River basin from year 2004 to 2006. Different temporal distribution of the PAHs pattern of contamination over the territory and constant distribution in time of the APs and heavier PAHs as well as the OCs pattern. Big circles representing higher levels of pattern contribution than small circles. Variables identification 1, naphthalene 2, acenaphtylene 3, acenapthene 4, fluorene 5, phenanthrene 6, anthracene 7, fluoranthene 8, pyrene 9, benzo(a) anthracene 10, chrysene 11, benzo(b)fluoranthene 12, benzo(k)fluoranthene 13, benzo(a)pyr-ene 14, indeno(l,2,3-cd)pyrene 15, dibenzo(a,h)anthracene 16, benzo(g,h,i)perylene 17, octyl-phenol 18, nonylphenol 19, tributylphosphate 20, a-HCH 21, HCB 22,2,4-DDE 23,4,4-DDE 24, 2,4-DDD 25, 4,4-DDD 26, 2,4-DDT 27, 4,4-DDT...

A set of n = 209 polycyclic aromatic compounds (PAC) was used in this example. The chemical structures have been drawn manually by a structure editor software approximate 3D-structures including all H-atoms have been made by software Corina (Corina 2004), and software Dragon, version 5.3 (Dragon 2004), has been applied to compute 1630 molecular descriptors. These descriptors cover a great diversity of chemical structures and therefore many descriptors are irrelevant for a selected class of compounds as the PACs in this example. By a simple variable selection, descriptors which are constant or almost constant (all but a maximum of five values constant), and descriptors with a correlation coefficient >0.95 to another descriptor have been eliminated. The resulting m = 467 descriptors have been used as x-variables. The y-variable to be modeled is the Lee retention index (Lee et al. 1979) which is based on the reference values 200, 300, 400, and 500 for the compounds naphthalene, phenanthrene, chrysene, and picene, respectively. 

Region Arene Oxides of Phenanthrene. Comparative Solvolytic Rate Constants of K-Re-gion and Non-K-Region Arene Oxides , J. Am. Chem. Soc. 1976, 98, 2965 - 2973. 

Fig. 27. Semilogarithmic plot of the nonradiative triplet rate constant against (E— o)/> for the normal and deuterated hydrocarbons listed in Ref. t)). The broken line, derived from phosphorescence spectra, is taken from Ref. t). The slopes of the two solid lines differ by a factor 1.35. (O.Ci-jjH, E = 4000 cm l 0 Ci fl Z>u, =5500 cm t). The following totally deuterated hydrocarbons are included benzene, triphenylene, acenaphtene, naphthalene, phenanthrene, chrysene, biphenyl, p-terphenyl, pyrene, 1,2-benzanthracene, anthracene (in the order of increasing /S). (From Siebrand and Williams, Ref. l)...

Phenanthrene (5.0 mg/L) in a methanol-water solution (2 3 v/v) was subjected to a high pressure mercury lamp or sunlight. Based on a rate constant of 6.53 x 10 Vmin, the corresponding half-life is 1.78 h (Wang et al., 1991). 

Hydrogenation experiments were conducted at 400 and 20 MPa for 2 h with a number of mono and bimetallic catalysts, all on an acidic alumina support Rate constants were calculated by assuming first order reaction kinetics for the disappearance of phenanthrene. The values for the rate constants and the results of the GC analysis (phenanthrene and its hydroderivatives) are summarised in Table III. 

Figure 8 Rate constants for electron attachment to solutes in tetramethylsilane at 295 K. For solutes numbered 1-28, see legends to Figs. 6 and 7. Other solutes 29—duroquinone, 30—CFI3I, 31—cycloC4F4, 32—C2HCI3, 33—phenanthrene. Dotted line is calculated diffusion rate. References for rate data [18,19,58,90,93,122,123,125,126] references for electron affinities [112-115].

FIGURE 9.63 Plots of om-phase-normalized gas-particle partitioning constant log Kp iun vs logarithm of the subcooled liquid vapor pressure, log pL, for a series of semivolatile PAHs partitioning on ( ) dioctyl phthalate (DOP) or (a) secondary organic aerosol (SOA) from photooxidized gasoline vapor. PAHs are as follows naphthalene, A acenaphthalene, B fluorene, C and C phenanthrene, D and D anthracene, E and E fluoranthene, F and F pyrene, G and G chrysene, H (adapted from Liang el al., 1997). 

The LFP method has been used to determine absolute rate constants for intermol-ecular carbene insertion reactions. Given the more convenient diazirine precursor (14) available for CgHsCCl, as opposed to the phenanthrene precursor (15) of CCI2, as well as the directly observable character of CeHsCCl, LFP studies have focused on... 

Evidence for photoassociation in the triplet manifold is at present inconclusive. Although Hoytink et al.20 have reported excimer phosphorescence from cooled ethanolic solutions of phenanthrene and naphthalene, concentration and temperature-dependent studies of the emission characteristics must be extended in order to distinguish photoassociation of the triplet state from intersystem crossing of the singlet excimer and possible triple-triplet annihilation. Certainly the decay constant of the molecular triplet state in fluid media is relatively insensitive to solute concentration21 although this... 

Figure 21.2 The interplay of transport and reaction, exemplified by the hypothetical vertical concentration profile of phenanthrene in a lake, (a) The rate of photolysis decreases with depth due to the diminishing light intensity with water depth, (b) Two possible vertical profiles of phenanthrene concentration if vertical mixing in the water column is strong, the profile is constant (profile 1). If vertical mixing is slow, a distinct vertical concentration gradient develops with small values at the water surface where photolysis is strongest (profile 2).

First, recall that the nondimensional Damkohler number, Da (Eq. 22-11 b), allows us to decide whether advection is relevant relative to the influence of diffusion and reaction. As summarized in Fig. 22.3, if Da 1, advection can be neglected (in vertical models this is often the case). Second, if advection is not relevant, we can decide whether mixing by diffusion is fast enough to eliminate all spatial concentration differences that may result from various reaction processes in the system (see the case of photolysis of phenanthrene in a lake sketched in Fig. 21.2). To this end, the relevant expression is L (kr / Ez)1 2, where L is the vertical extension of the system, Ez the vertical turbulent diffusivity, and A, the first-order reaction rate constant (Eq. 22-13). If this number is much smaller than 1, that is, if... 

Unfortunately, diaromatic hydrocarbons are not the only potential hydrocarbon inhibitors present in gas oils and diesel fuels. Triaromatic hydrocarbons are also present in significant amounts (see Fig. 2) (12). It is known that triaromatics, such as phenanthrene, are even stronger inhibitors than diaromatics for the HDS of thiophene compounds. Equilibrium adsorption constants for phenanthrene and naphthalene have been reported to be 65 and 11 atm-1, respectively (131). In Iranian gas oil, triaromatics have been reported to be present at about one-tenth the concentration of diaromatics (109). Thus, the contribution to inhibition of HDS reactions by triaromatics (XTri[Tri]) could be about the same as that from diaromatics, even though triaromatics are present in smaller amounts. 

Dimercury(I) n complexes are formed between aromatic compounds and Hg2(AsF6)2 in liquid S02 as solvent.113,121 Insoluble complexes with the ratio arene Hg2+ = 1 1 (arene = benzene, naphthalene, 2-methylnaphthalene, 2,6-dimethylnaphthalene, acenaphthene, fluor-anthrene, phenanthrene, anthracene, 9,10-dimethylanthracene or 1,3-dinitrobenzene) or 1 2 (arene = 9,10-benzophenanthrene) have been characterized by elemental analysis and, in some cases, by Raman spectrometry.113,120 The 13CNMR data allow the estimation of formation constants for the hexamethylbenzene, p-xylene and 1,4-dichlorobenzene complexes together with the chemical shifts for the bound substrates in these cases.121 Probably the coordination compounds of dimercury(I) salts with carbazole, dibenzofuran and diben-zothiophene are also n complexes.122... 

For block copolymers with a polyacid or polybase block, the structure and properties of micellar solutions depend on the pH. For example, Morishima et al. (1982b) found that for a poly(9-vinylphenanthrene)-poly(methacrylic acid) (PVPT-PMA) diblock in water, the rate constant for the fluorescence quenching of phenanthrene groups by oxidative non-ionic quencher is pH dependent. These authors suggested that at low pH the polyacid units are not fully ionized and may participate in the formation of hydrophobic domains, cooperatively with PVPT. An alternative explanation is that the PM A chains are less solvated when... 

For benzene, it has not been possible to measure directly the rate constant kv for deprotonation of the benzenonium ion in order to complete the determination of Ka (— kp/kg). However, this has been possible for 1-protonated naphthalene,106 9-protonated phenanthrene,25 9-protonated anthracene, and 2-protonated benzofuran.75 In the case of the naphthalene, Thibblin and Pirinccioglu showed that the naphthalene hydrate is sufficiently reactive to form the naphthalenonium ion in aqueous azide buffers (pH 4-5).106 Formation of this ion leads to competition between loss of a proton and trapping by azide ion to form the 2-azido-l,2-dihydronaphthalene. From the trapping ratio kp is determined as 1.6xlOlos 1 by the usual clock method. 

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