34526-71-1Relevant articles and documents
Photocatalytic reduction of nitroorganics over illuminated titanium dioxide: Electron transfer between excited-state TiO2 and nitroaromatics
Ferry, John L.,Glaze, William H.
, p. 2239 - 2244 (2007/10/03)
The present study investigates the steady-state photocatalytic reduction of methyl viologen and a suite of monosubstituted nitrobenzenes. Reduction was carried out in deoxygenated, illuminated aqueous slurries of titanium dioxide (Degussa P25) in the presence of a sacrificial electron donor, 2-propanol. Langmuir-Hinshelwood plots were obtained for the reduction of each compound and found to be linear, with an average correlation of 0.98 and with a standard deviation on the correlations of 0.02. The concentration independent rates for nitroaromatic reduction obtained from these plots were normalized against the rate of methyl viologen reduction and the ratio was used to solve for the rate constant of nitroaromatic reduction, assuming a bimolecular model. The assumptions behind this procedure were tested by the use of the Marcus expression. Using the reorganization energy for the reaction as the fitting variable, it was possible to fit the measured rates to the predicted rates with a reorganization energy of 138 kJ/mol.
Entropy Changes and Electron Affinities from Gas-Phase Electron-Transfer Equilibria: A(-) + B = A + B(-)
Chowdhury, Swapan,Heinis, Thomas,Grimsrud, Eric P.,Kebarle, Paul
, p. 2747 - 2752 (2007/10/02)
By measuring the electron-transfer equilibria 1, A(-) + B = A + B(-), at 150 deg C with a pulsed electron high-pressure mass spectrometer we determined the ΔGo1 values involving 12 new compounds.Measurements of the temperature dependence of K1 for 21 reactions involving some of the new compounds and many compounds whose ΔGo1 had been determined previously led, via van't Hoff plots, to ΔHo1 and ΔSo1 values.These were interconnecting such that ΔHo and ΔSo continuous scales (ladders) were obtained.These were anchored to SO2 whose electron affinity is accurately known.Available geometries and vibrational frequencies for SO2 and SO2(-) permit the evaluation of So(SO2(-)) - So(SO2).Through the ΔSo scale the So(B(-)) - So(B) for the other compounds B could be obtained also.Certain regularities in the So(B(-)) - So(B) data permitted entropy estimates to be made also for compounds for which no van't Hoff plots were made.In this manner a table of ΔHo, ΔSo, and ΔGo data for the electron capture e + B = B(-) was obtained, which contains some 50 compounds B.Most of the compounds are substituted benzenes, quinones, conjugated acid anhydrides, and perfluorinated organics.
Electron affinity of SF6 and perfluoromethylcyclohexane. The unusual kinetics of electron transfer reactions A- + B = A + B-, where A = SF6 or perfluorinated cyclo-alkanes
Grimsrud, E. P.,Chowdhury, S.,Kebarle, P.
, p. 1059 - 1068 (2007/10/02)
Measurements of the equilibria ( 1 ): A- + B = A + B- with a pulsed electron high pressure mass spectrometer lead to ΔG, ΔH, and ΔS.Equilibria involving SF6 as A and perfluoromethylcyclohexane C7F14 provide electron affinities E.A.(SF6) =1.05 +/- 0.1 eV and E.A.(C7F14) =1.06 +/- 0.15 eV.The kinetics of reactions (1) involving the above two compounds were studied.The rate constants kj for SF6- + B = SF6 + B- were found to increase with exothermicity of the reaction.The temperature dependence for k f was determined.B compounds leading to high exothermicities were associated with kj at the collision limit and essentially no temperature dependence.B of progressively lower electron affinity led to kf below the collision limit and negative temperature dependence, while B with the lowest E.A. but still leading to exothermic reaction produced lowest kf with positive temperature dependence.A model is provided explaining the above behavior.The known large change of geometry between SF6- and SF6 introduces an internal barrier in the reaction coordinate for the reactions ( 1 ) involving SF6.
