2348-49-4Relevant academic research and scientific papers
High resolution electronic absorption spectra of aniline, anilino and silicon dioxide.
Bayrakceken, Fuat,Karaaslan, Ipek S
, p. 2785 - 2789 (2003)
High resolution electronic absorption spectra of aniline and anilino free radical have been recorded in the vapor phase at room temperature by flash photolysis technique, and subsequent reactions have been investigated by kinetic spectroscopy. It was poss
Dual Spin Polarization of CIDEP in Benzil/Quencher Systems
Okutsu, Tetsuo,Yano, Kouki,Kawai, Akio,Obi, Kinichi
, p. 5401 - 5405 (1991)
Dual spin polarization of triplet benzil was investigated by the time-resolved ESR technique.Spin polarization of triplet benzil showed only absorption in rigid matrices at 77 K.However, the phase of CIDEP signals caused by the triplet mechanism showed absorption or emission depending on the concentration of quenchers at room temperature.Both polarizations were generated through a one-photon absorption process.Absorptive polarized radicals were produced from free benzil, whereas emissive polarized radicals were produced from benzil/quencher complex.
The Photochemically Induced Oxidation of Aniline by Hydroperoxides: An Electron Paramagnetic Resonance Study. Part II.
Grossi, Loris
, p. 9511 - 9516 (2007/10/02)
The oxidation reaction of aniline by tertiary hydroperoxides, induced photochemically, was studied.The peculiar radical intermediates, nitroxides and peroxy radicals, involved in the reaction mechanism were detected and identified by EPR spectroscopy.The presence of these intermediates confirm that PhNO is the first product of the oxidation of aniline and the PhNH radical as its precursor.
Reactivities of Chlorine Atoms and Peroxyl Radicals Formed in the Radiolysis of Dichloromethane
Alfassi, Z. B.,Mosseri, S.,Neta, P.
, p. 1380 - 1385 (2007/10/02)
Radiolysis of dichloromethane (DCM) leads to formation of primary oxidizing radicals and carbon-centered radicals.The latter react with oxygen to yield peroxyl radicals.The yields and chemical behavior of these intermediates were studied by pulse radiolysis of DCM solutions containing various solutes: phenols, anilines, dimethoxybenzene, hexamethylbenzene,cyclohexene, dimethyl sulfoxide, and zinc tetratolylporphyrin.At low concentrations, some of these solutes were found to be oxidized by two peroxyl radicals, CH2ClO2* and CHCl2O2*, with different rate constants.At higher concentrations, the solutes react also with the primary radicals: Cl atoms and the radical cations CH2Cl2(+*), with diffusion-controlled rate constants.The rates of these reactions were determined by competition kinetics because of the very short lifetimes of the species.Cl atoms were found to have a half-life of about 5 ns in DCM, reacting predominantly with the solvent by hydrogen abstraction.The radical cations decay within a fraction of a nanosecond.The total yield of these primary radicals was determined to be G = 3.6 and appears to be divided about equally between Cl and the radical cations.The total yield of oxidation, by the primary and the peroxyl radicals, was found to be G = 7.5.Cl atoms were found to be very reactive in electron transfer as well as addition and hydrogen abstraction reactions.
Rate Constants and Mechanism for the Reaction of Hydrogen Atoms with Aniline
He, Y. Z.,Cui, J. P.,Mallard, W. G.,Tsang, W.
, p. 1510 - 1513 (2007/10/02)
The hydrogen atom induced decomposition of aniline was studied by using a heated single-pulse shock tube.Hydrogen atoms were generated from hexamethylethane decomposition at sufficiently high aniline to hexamethylethane concentration so that the main reactions were abstraction of the amine hydrogen and displacement of the amino group.The rate expressions are ka(H+C6H5NH2 -> C6H5NH+H2)=1.8 E11 exp(-5846/T) L/(mol s) and kd(H+C6H5NH2 -> C6H6+NH2)=2.2 E10 exp(-3735/T) L/(mol s) over the temperature range of 1000-1140 K and pressures near 3.3 atm of argon.These rate expressions are compared to earlier results on toluene and phenol.
Kinetic Applications of Electron Paramagnetic Resonance Spectroscopy. 42. Some Reactions of the Bis(trifluoromethyl)aminoxyl Radical
Doba, T.,Ingold, K. U.
, p. 3958 - 3963 (2007/10/02)
Absolute rate constants have been determined in Freon solvents over a temperature range from ca. 190 to 300 K for H atom abstraction by (CF3)2NO. from 11 substrates and for the addition of this radical to CH2=CCl2.Some values found for log A (M
Gas-Phase Nucleophilic Reactivities of Phenylnitrene (PhN-*) and Sulfur Anion Radicals (S-/.) at sp3 and Carbonyl Carbon
McDonald, Richard N.,Chowdhury, A. Kesem
, p. 198 - 207 (2007/10/02)
The reactions of PhN-/. with a series of carbonyl-containing molecules (aldehydes, ketones, and esters) were shown to proceed via an addition/fragmentation mechanism, PhN-* + R2C=O -> -)R2> -> PhN=C(O-)R + *R, producing various acyl anilide anion products.In several cases, the tetrahedral intermediate anion radicals were observed as minor ions.The intrinsic reactivity of the carbonyl-containing molecules was aldehydes > ketones > esters, where similar R groups were involved.The overall exothermicities of these reactions did not appear to play the major role in determining the relative rates (krelC=O) for these reactions.From the reaction of PhN-* with cyclobutanone, a new type of anion radical, PhN=C(O-)CH2* (m/z 133) (+ C2H4) was produced; the loss of C2H4 was considered due to the ring strain in the ketone.With cyclopentanone, cyclohexanone, and cycloheptanone, the anion radicals PhN=C(O-)(CH2)n* (n = 4-6) were the exclusive product ions.PhN-* was shown to be a poor nucleophile in SN2 displacement reactions with CH3X molecules (X = Cl, Br, O2CCF3).S-* was shown to exhibit modest SN2 nucleophilicity with CH3Cl and CH3Br.The reactions of S-* with CF3CO2R proceed via both SN2 displacement and carbonyl addition/fragmentation mechanisms: with R = CH3, the anion products were 65percent CF3CO2- and 35percent CF3COS-; from R = C2H5, the product ions were 4percent CF3CO2- and 96percent CF3COS-.These data yield the ratio kCH3/kC2H5 = 16 for SN2 displacement by S-* at these alkyl groups.The reactions of PhN-* with CO2, COS, CS2, and O2 are also reported.The reaction of PhN-* with CS2 to produce S-* as a major channel was used as the source of this atomic anion radical.In several reactions occuring at nearly the collison limit, selectivity was observed for (a) which of two reaction centers were attacked to give products and (b) which of two mechanisms would be dominant in the overall reaction.
Carbon-Hydrogen Bond Dissociation Energies in Alkylbenzenes. Proton Affinities of the Radicals and the Absolute Proton Affinity Scale
Meot-Ner (Mautner), Michael
, p. 5 - 10 (2007/10/02)
Rate constants (k) were measured for proton-transfer reactions from alkylbenzene ions RH+ to a series of reference bases B, i.e., RH+ + B -> BH+ + R*.For exothermic reactions (ΔH -1.For example, the reaction C6H5CH3+ + B -> BH+ + C6H5CH2* is fast (reaction efficiency = k/kcol >/= 0.5) when B = MeO-t-Bu or stronger bases, but k/kcol is significantly smaller when B is n-Pr2O or weaker bases.From the falloff curve of reaction efficiency vs.PA(B), we find PA(n-Pr2O) = PA(C6H5CH2*) + 0.8 kcal mol-1 = 200.0 kcal mol-1.Since PA(C6H5CH2*) is obtained from known thermochemical data, this relation defines the absolute PA of n-Pr2O.Through a ladder of known PA, we then obtain PA(i-C4H8) = 186.8 kcal mol-1; we also obtain the absolute PAs of other oxygen bases.Falloff curves of reaction efficiencies of 3-FC6H4CH3+, C6H5C2H5+, C6H5-n-C3H7+, and C6H5-i-C3H7+ with these reference bases give then the following PAs of R* and R-H bond dissociation energies (Do) (all in kcal mol-1) as R*, PA(R*), Do(R-H): 3-FC6H4CH2*, 197.2, 89.4; , 197.9, 86.2; , 199.1, 86.1; , 199.6, 86.1.In similar manner, rate constants for H+ transfer from C6H5NH2+ to reference pyridines and amines yield PA(C6H5NH*) = 221.5 and Do(C6H5NH-H) = 85.1 kcal mol-1 (1 kcal mol-1 = 4.18 kJ mol-1).
