Solvated electron mobility in liquid tert-butanol

1995 ◽  
Vol 73 (3) ◽  
pp. 389-391 ◽  
Author(s):  
Yixing Zhao ◽  
Gordon R. Freeman
Keyword(s):  
Activation Energy ◽  
Ammonium Perchlorate ◽  
Perchloric Acid ◽  
Electron Mobility ◽  
Diffusion Mechanism ◽  
Solvated Electron ◽  
Solvated Electrons ◽  
Tert Butanol ◽  
Diffusion Controlled ◽  
Diffusion Controlled Reaction

The mobility μe of solvated electrons in liquid tert-butanol was estimated from the measured rate constant of the diffusion-controlled reaction [Formula: see text] combined with the measured molar conductivities of perchloric acid and ammonium perchlorate solutions; T = 300–330 K. The values μe = 4.1 × 10−8 m2 V−1 s−1 at 300 K and Eμ = 41 kJ mol−1 indicate that electrons migrate by a hopping mechanism in liquid tert-butanol. This contrasts with the ion-like diffusion mechanism of [Formula: see text] in methanol and ethanol. Keywords: tert-butanol, solvated electron, activation energy, mobility.

Article

1998 ◽  
Vol 76 (4) ◽  
pp. 411-413
Author(s):  
Yixing Zhao ◽  
Gordon R Freeman
Keyword(s):  
Absorption Spectrum ◽  
Optical Absorption ◽  
Temperature Dependence ◽  
Optical Absorption Spectrum ◽  
Infrared Light ◽  
Solvated Electron ◽  
Solvated Electrons ◽  
Tert Butanol ◽  
Solvent Dependence ◽  
Increasing Temperature

The energy and asymmetry of the optical absorption spectrum of solvated electrons, es- , change in a nonlinear fashion on changing the solvent through the series HOH, CH3OH, CH3CH3OH, (CH3)2CHOH, (CH3)3COH. The ultimate, quantum-statistical mechanical, interpretation of solvated electron spectra is needed to describe the solvent dependence. The previously reported optical spectrum of es- in tert-butanol was somewhat inaccurate, due to a small amount of water in the alcohol and to limitations of the infrared light detector. The present note records the remeasured spectrum and its temperature dependence. The value of the energy at the absorption maximum (EAmax) is 155 zJ (0.97 eV) at 299 K and 112 zJ (0.70 eV) at 338 K; the corresponding values of G epsilon max (10-22 m2 aJ-1) are 1.06 and 0.74. These unusually large changes are attributed to the abnormally rapid decrease of dielectric permittivity of tert-butanol with increasing temperature. The band asymmetry at 299 K is Wb/Wr = 1.8.Key words: optical absorption spectrum, solvated electron, solvent effects, tert-butanol, temperature dependence.

Influence of counterion species on the dehydroxylation of Ca2+-, Mg2+-, Na+- and K+-exchanged Wyoming montmorillonite

2000 ◽  
Vol 64 (2) ◽  
pp. 337-346 ◽  
Author(s):  
H. J. Bray ◽  
S. A. T. Redfern
Keyword(s):  
Activation Energy ◽  
X Ray Diffraction ◽  
Interlayer Cation ◽  
Reaction Step ◽  
Octahedral Sheet ◽  
X Ray ◽  
First Order ◽  
Diffusion Controlled ◽  
Diffusion Controlled Reaction

AbstractThe dehydroxylation of Ca-, K-, Mg- and Na-saturated Wyoming montmorillonite has been studied by thermogravimetry (TG), infrared (IR) spectroscopy and X-ray diffraction (XRD). Samples saturated with either Ca2+ or Mg2+ show a predominantly diffusion-controlled reaction step, whereas Wyoming montmorillonite with Na+ and K+ in the interlayer exhibit control closer to first order. The activation energy of dehydroxylation is not significantly correlated to the type of interlayer cation present, in turn demonstrating that the role of vacancy location in the octahedral sheet is more significant a control on dehydroxylation.

Kinetic Study of Oxidative Scission in Natural Rubber by Wallace Plasticity Measurements

1992 ◽  
Vol 65 (1) ◽  
pp. 1-6 ◽  
Author(s):  
L. H. Gan ◽  
S. C. Ng ◽  
K. K. Chee
Keyword(s):  
Activation Energy ◽  
Kinetic Parameter ◽  
Natural Rubber ◽  
Kinetic Data ◽  
Oxidative Degradation ◽  
Chain Scission ◽  
Thermal Oxidative Degradation ◽  
Diffusion Controlled ◽  
Kinetics Of ◽  
Diffusion Controlled Reaction

Abstract The kinetics of thermal oxidative degradation of natural rubber (NR) have been studied by Wallace plasticity measurements. On the basis of the Kotliar's model of random chain scission, an expression was derived to interpret the kinetic data collected over a range of temperatures from 80 to 160°C. It has been shown that the kinetic parameter resulting from the present analysis, indeed refers to a diffusion-controlled reaction with an overall activation energy estimated to be 135 ± 6 kJ · mol−1. In addition, the implications of plasticity retention index, which measures the oxidizability of NR, are discussed.

scholarly journals The Energy-Efficient Processing of Fine Materials by the Micropyretic Synthesis Route

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
H. P. Li
Keyword(s):  
Energy Efficient ◽  
Processing Time ◽  
Combustion Temperature ◽  
Processing Parameters ◽  
The Novel ◽  
Diffusion Controlled ◽  
Efficient Processing ◽  
The One ◽  
Processing Techniques ◽  
Diffusion Controlled Reaction

Energy-efficient processing of TiB compound with nanowhiskers by micropyretic synthesis is investigated in this paper. Micropyretic synthesis not only offers shorter processing time but also excludes the requirement for high-temperature sintering and it is considered as the one of the novel energy-saving processing techniques. Experimental study and numerical simulation are both carried out to investigate the correlation of the processing parameters on the microstructures of the micropyretically synthesized products. The diffusion-controlled reaction mechanism is proposed in this study. It is noted that nanosize TiB whiskers only occurred when the combustion temperature is lower than the melting point of TiB but higher than the extinguished temperature. The results generated in the numerical calculation can be used as a helpful reference to select the proper route of processing nanosize materials. The Arrhenius-type plot of size and temperature is used to calculate the activation energy of TiB reaction. In addition to verifying the accuracy of the experimental measures, the reaction temperature for producing the micropyretically synthesized products with nanofeatures can be predicted.

The Decomposition of Perchloric Acid on Metal Oxide Catalysts

1971 ◽  
Vol 49 (17) ◽  
pp. 2827-2831 ◽  
Author(s):  
R. Gilbert ◽  
P. W. M. Jacobs
Keyword(s):  
Thermal Decomposition ◽  
Metal Oxide ◽  
Proton Transfer ◽  
Ammonium Perchlorate ◽  
Perchloric Acid ◽  
Catalyst Surface ◽  
Copper Chromite ◽  
Oxide Catalysts ◽  
The Other ◽  
Metal Oxide Catalysts

The thermal decomposition of perchloric acid has been investigated on five Harshaw catalysts: copper chromite, alumina, iron(III) oxide, copper(II) oxide, and manganese(IV) oxide (the last three being supported on alumina). Manganese(IV) oxide gave complex kinetics which were not fully analyzed but on the other four catalysts the reaction was.first order. Activation energies were: copper chromite, 54 kcal/mol; alumina, 28.8 kcal/mol; iron(III) oxide, 28.6 kcal/mol; copper(II) oxide, 39.0 kcal/mol. A mechanism is proposed for the decomposition which involves proton transfer to an accepter (typically an O2− ion) in the catalyst surface followed by decomposition of the ClO4− anion formed in this process. Some observations on the catalyzed thermal decomposition of ammonium perchlorate are presented.

Distance-Dependent Diffusion-Controlled Reaction of•NO and O2•−at Chemical Equilibrium with ONOO−

2010 ◽  
Vol 114 (49) ◽  
pp. 16584-16593 ◽  
Author(s):  
Horacio Botti ◽  
Matías N. Möller ◽  
Daniel Steinmann ◽  
Thomas Nauser ◽  
Willem H. Koppenol ◽  
...  
Keyword(s):  
Chemical Equilibrium ◽  
Diffusion Controlled ◽  
Diffusion Controlled Reaction
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