4971-41-9Relevant academic research and scientific papers
Unique Pressure Effects on the Absolute Kinetics of Triplet Benzophenone Photoreduction in Supercritical CO2
Roberts, Christopher B.,Chateauneuf, John E.,Brennecke, Joan F.
, p. 8455 - 8463 (1992)
Laser flash photolysis studies of the hydrogen atom abstraction reaction of triplet benzophenone from 2-propanol and 1,4-cyclohexadiene in supercritical CO2 reveal unusual pressure effects on absolute rate constants.Monitoring reactivity close to the critical temperature (Tc) revealed that bimolecular rate constants increase sharply with a decrease in pressure, approaching the critical point.Kinetic investigations along an isotherm further removed from Tc and predictive calculations on the pressure effect expected in supercritical CO2 indicate that enhanced reactivity is due to local substrate clustering.
Laser Flash Photolysis Study of the Hydrogen Atom Transfer Reaction from Triplet 1-Naphthol to Ground Benzophenone
Shizuka, Haruo,Hagiwara, Hiroyuki,Fukushima, Masaru
, p. 7816 - 7823 (1985)
Laser flash photolyses at 337 nm have been carried out methanol solutions of the 1-naphthol and benzophenone system.It is found that hydrogen atom transfer reaction from the triplet 1-naphthol 3ROH* (produced by triplet sensitization
Benzophenone Triplet Properties in Acetonitrile and Water
Bensasson, Rene V.,Gramain, Jean-Claude
, p. 1801 - 1810 (1980)
The technique of time resolved laser flash spectoscopy has been used to study the photophysical and photochemical properties of the lowest triplet of benzophenone in water and acetonitrile.New estimates have been obtained for the triplet extinction coeffi
Hydrogen Abstraction in the Neutral Molecular Cluster of Benzophenone and Hydrogen Domors Formed in a Supersonic Free Jet Expansion
Matsushita, Yoshihisa,Kajii, Yoshizumi,Obi, Kinichi
, p. 6566 - 6570 (1992)
Photochemical reactions of benzophenone with hydrogen donors in neutral molecular clusters formed in a supersonic free jet expansion were studied.It was found that benzophenone undergoes photoreduction to form benzophenone ketyl radical in the benzophenon
Laser Flash Photolysis Studies on Proton-Enhanced Hydrogen Atom Transfer Reaction from Triplet Naphthol to Benzophenone via a Triplet Exciplex
Kaneko, Shouichi,Yamaji, Minoru,Hoshino, Mikio,Shizuka, Haruo
, p. 8028 - 8033 (1992)
The laser flash photolysis study at 355 nm in the 1-naphthol (ROH) and benzophenone (BP) system with and without H2SO4 has been carried out in acetonitrile-water (4:1 v/v) or methanol at 290 K.For the ROH (3.0 * 10-3 M)-BP (6.7 * 10-3/sup
Magnetic Field Effects on the Hydrogen Abstraction Reactions of Triplet Benzophenone with Thiophenol in Nonviscous Homogenous Solutions
Wakasa, Masanobu,Hayashi, Hisaharu
, p. 15640 - 15643 (1996)
The hydrogen abstraction reaction of triplet benzophenone with thiophenol at room temperature was investigated in several nonviscous homogeneous solutions (η = 0.29-3.33 cP) by means of a nanosecond laser flash photolysis technique under magnetic fields o
Photochemical Reaction of Excited Benzophenone in the Gas Phase
Matsushita, Yoshihisa,Kajii, Yoshizumi,Obi, Kinichi
, p. 4455 - 4458 (1992)
Photochemical reactions of benzophenone with hydrogen-donating compounds have been studied in the gas phase.It has been found that the photoreduction of excited benzophenone proceeds to form benzophenone ketyl radical without contributions from surroundin
Time-Resolved Fluorescence Monitoring of Aromatic Radicals in Photoinitiated Processes
Shield, Stephanie R.,Harris, Joel M.
, p. 2576 - 2583 (1998)
Photolytic initiation of free radical reactions is important to many areas of technology; time-resolved monitoring of submicromolar concentrations of radicals produced during the course of these reactions is needed to provide information about the rate of initiation and its competition with radical recombination. In this work, time-resolved laser-induced fluorescence is evaluated for monitoring of diphenylketyl radicals produced by photoreduction of the triplet state of benzophenone. Fluorescence from the doublet-doublet transition of the radical is excited with a continuous wave laser and provides a sensitive method to detect these intermediates at nanomolar concentrations and to study their kinetics in solution on time scales from a few microseconds to hundreds of milliseconds. The ketyl radical fluorescence measurements of radical initiation reactions allowed the H atom abstraction rate constant by triplet benzophenone from both 2-propanol and benzhydrol to be determined, where kH = (2.1 ± 0.1) × 106 M-1 s-1 for 2-propanol and kH = (4.4 ± 0.1) × 106 M-1 s-1 for benzhydrol. The diphenylketyl radical recombination rate constant was also determined by time-resolved fluorescence monitoring of the decay of the radical population and found to be kr = (1.9 ± 0.2) × 108 M-1 s-1. Formation kinetics could be measured on a microsecond time scale from radical populations as low as 45 nM; decay kinetics could be followed on a millisecond time scale from 20 nM radical concentrations.
Nanosecond Flash Studies of Reduction of Benzophenone by Aliphatic Amines. Quantum Yields and Kinetic Isotope Effects
Inbar, Shai,Linschitz, Henry,Cohen, Saul G.
, p. 1048 - 1054 (1981)
Nanosecond flash photolysis, steady irradiation, and deuterium substitution studies have been carried out on solutions of benzophenone with added redutants.Quantum yields (φketyl) for reduction in benzene of benzophenone triplet to ketyl radica
Picosecond and Nanosecond Studies of the Photoreduction of Benzophenone by N,N-Diethylaniline and Triethylamine
Devadoss, C.,Fessenden, Richard W.
, p. 7253 - 7260 (1991)
The photoreduction of benzophenone by N,N-diethylaniline and trimethylamine has been examined in a number of solvents by both nano- and picosecond laser photolysis.With diethylaniline, electron transfer is the primary step and the spectrum of the ion pair has been detected even in nonpolar solvents such as benzene and cyclohexane.Rapid proton transfer then takes place to form a high yield of the ketyl radical.The lifetime of the ion pair in benzene is about 900 ps.In acetonitrile the ion pair dissociates into individual ions which then decay by back electron transfer and proton transfer.A spectral shift to the red occurs over 100 ps as the contact ion pair dissociates.In acidic alcohols such as methanol and trifluoroethanol proton transfer from the alcohol occurs to produce the ketyl radical.In the case of triethylamine, no distinct absorption band for benzophenone anion was seen in picosecond experiments but difference spectra, which removed much of the spectrum of benzophenone triplet, clearly showed some contribution from the anion.For this compound, it is likely that electron transfer occurs first followed by very fast proton transfer.
