Mobilities of solvated electrons in polar solvents from scavenging rate constants

1980 ◽  
Vol 84 (10) ◽  
pp. 1186-1189 ◽  
Author(s):  
J. A. Delaire ◽  
M. O. Delcourt ◽  
J. Belloni
Keyword(s):  
Rate Constants ◽  
Solvated Electrons ◽  
Polar Solvents

Is there any Correlation between the Mobility and the Absorption Spectra of Solvated Electrons in Polar Solvents?

2000 ◽  
Vol 214 (10) ◽  
Author(s):  
P. Krebs
Keyword(s):  
Absorption Spectrum ◽  
Optical Absorption ◽  
Absorption Spectra ◽  
Optical Absorption Spectrum ◽  
Chem Phys ◽  
Solvated Electrons ◽  
Polar Solvents ◽  
Excess Electrons

Some years ago Jay-Gerin and Ferradini attempted to establish a correlation between the optical absorption spectrum and the mobility of excess electrons in various polar solvents (J. Chem. Phys.

Switchover of reactions of solvated electrons with nitrate ions and ammonium ions in propanol–water solvents

1993 ◽  
Vol 71 (9) ◽  
pp. 1297-1302 ◽  
Author(s):  
Tae Bum Kang ◽  
Gordon R. Freeman
Keyword(s):  
Rate Constants ◽  
Pure Water ◽  
Reaction Rates ◽  
Binary Solvents ◽  
Ammonium Ions ◽  
Concentrated Solutions ◽  
Solvated Electrons ◽  
Reaction Rate Constants ◽  
Water Solvent ◽  
Arrhenius Temperature

The reaction rate constants of [Formula: see text] with ammonium nitrate (~ 0.1 mol m−3) in 1-propanol-water and 2-propanol–water binary solvents correspond to [Formula: see text] reaction in the water-rich solvents, and to [Formula: see text] reaction in alcohol-rich solvents. The overall rate constant is smaller in solvents with 40–99 mol% water, with a minimum at 70 mol% water. The Arrhenius temperature coefficient is 26 kJ mol−1 in each pure propanol solvent, increases to 29 kJ mol−1 at 40 mol% water, then decreases to 17 kJ mol−1 in pure water solvent. The high reaction rates in the single component solvents, alcohol or water, are limited mainly by solvent processes related to shear viscosity (diffusion) and dielectric relaxation (dipole reorientation). Rate constants reported for concentrated solutions (50–1000 mol m−3) of ammonium and nitrate salts in methanol (Duplâtre and Jonah. J. Phys. Chem. 95, 897 (1991)) have been quantitatively reinterpreted in terms of the ion atmosphere model.

The reactivity of allyl and propargyl alcohols with solvated electrons: temperature and solvent effects

1979 ◽  
Vol 57 (8) ◽  
pp. 839-845 ◽  
Author(s):  
Alexei M. Afanassiev ◽  
Kiyoshi Okazaki ◽  
Gordon R. Freeman
Keyword(s):  
Activation Energy ◽  
Ethylene Glycol ◽  
Rate Constants ◽  
Allyl Alcohol ◽  
Trap Depth ◽  
Activation Energies ◽  
Butyl Alcohol ◽  
Solvated Electrons ◽  
Tert Butyl ◽  
Tert Butyl Alcohol

The rate constants k1 for the reaction of solvated electrons with allyl alcohol in a number of hydroxylic solvents differ by up to two orders of magnitude and decrease in the order tert-butyl alcohol > 2-propanol > 1-propanol ≈ ethanol > methanol ≈ ethylene glycol > water. In methanol and ethylene glycol the rate constants (7 × 107 M−1 s−1 at 298 K) and activation energies (16 kJ/mol) are equal, in spite of a 32-fold difference in solvent viscosity (0.54 and 17.3 cP, respectively) and 3-fold difference in its activation energy (11 and 32 kJ/mol, respectively). The reaction in tert-butyl alcohol is nearly diffusion controlled and has a high activation energy that is characteristic of transport in that liquid (E1 = 31 kJ/mol, Eη = 39 kJ/mol). The activation energies in the other alcohols are all 16 kJ/mol, and it is 14 kJ/mol in water. They do not correlate with transport properties. The solvent effect is connected primarily with the entropy of activation. The rate constants correlate with the solvated electron trap depth. When the electron affinity of the scavenger is small, a favorable configuration of solvent molecules about the electron/scavenger encounter pair is required for the electron jump to take place. The behavior of the rate parameters for propargyl alcohol is similar to that for allyl alcohol, but k1, A1, and E1 are larger for the former. The ratio k(propargyl)/k(allyl) at 298 K equals 10.5 in water and decreases through the series, reaching 1.3 in tert-butyl alcohol. Rate parameters for several other scavengers are also reported.

Dynamic behavior of solvated electrons produced by photoionization of indole and tryptophan in several polar solvents

1989 ◽  
Vol 93 (11) ◽  
pp. 4527-4530 ◽  
Author(s):  
Yoshinori Hirata ◽  
Noriko Murata ◽  
Yuichiro Tanioka ◽  
Noboru Mataga
Keyword(s):  
Dynamic Behavior ◽  
Solvated Electrons ◽  
Polar Solvents

Kinetics and isotope effects of the β-elimination reactions of some 2,2-di(4-nitrophenyl)chloroethanes promoted by tetramethylguanidine in aprotic solvents

1985 ◽  
Vol 63 (6) ◽  
pp. 1194-1197 ◽  
Author(s):  
Arnold Jarczewski ◽  
Malgorzata Waligorska ◽  
Kenneth T. Leffek
Keyword(s):  
Rate Constants ◽  
Isotope Effects ◽  
Activation Parameters ◽  
Aprotic Solvents ◽  
Polar Solvents ◽  
Deuterium Isotope Effects ◽  
Elimination Reactions

Rate constants for the β-elimination of HCl from 2,2-di(4-nitrophenyl)-1,1-dichloroethane (I) and 2,2-di(4-nitrophenyl)-1,1,1-trichloroéthane (II) promoted by tetramethylguanidine in the aprotic solvents acetonitrile, tetrahydrofuran, and n-hexane have been measured. The activation parameters are characterized by small enthalpies of activation (4.1 to 7.3 kcal mol−1) and large negative entropies of activation (−35 to −50 cal mol−1 deg−1). The primary deuterium isotope effects at 20° C range from kH/kD = 4.8 to 10.3. The results are interpreted to indicate an (EcB)1 mechanism for both substrates I and II in acetonitrile solvent and an E2H or mixed (ElcB)1–E2H mechanism in the less polar solvents, tetrahydrofuran and n-hexane.

OXIDATION OF N, N-DIMETHYLANILINE: II. THE REACTION WITH OXYGEN CATALYZED BY BENZOYL PEROXIDE

1963 ◽  
Vol 41 (12) ◽  
pp. 2945-2955 ◽  
Author(s):  
Donald M. Graham ◽  
Robert B. Mesrobian
Keyword(s):  
Hydrogen Peroxide ◽  
Benzoyl Peroxide ◽  
Rate Constants ◽  
Quantitative Yield ◽  
Chain Reaction ◽  
Polar Solvents ◽  
Oxidation Rates ◽  
Presence And Absence ◽  
A Chain

When benzoyl peroxide was used to initiate the reaction of oxygen with N,N-dimethylaniline, a chain reaction was shown to occur, resulting in an almost quantitative yield of hydrogen peroxide. The reaction was inhibited by mercaptan and benzoquinone, but not by hydroquinone, and was shown to be autoinhibited as well. The rate of oxidation was observed to be much greater in polar solvents, such as acetonitrile or methanol, than in non-polar solvents such as toluene and benzene. Diethyl- and dipropyl-aniline exhibited no chain characteristics under similar conditions, whereas dimethylbenzylamine and dimethyldodecylamine did not react at all.A mechanism has been postulated involving both semiquinone and peroxide chain carriers which is consistent with all of these observations. From an analysis of the oxidation rates in the presence and absence of mercaptan inhibition, the appropriate rate constants have been determined.

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