ChemInform Abstract: MNDO-PM3 Calculations of Activation Energies for the Addition of Chlorinated C1 and C2 Radicals to Chlorinated Ethylenes and Acetylenes.

ChemInform ◽  
2010 ◽  
Vol 22 (37) ◽  
pp. no-no
Author(s):  
Y. SHI ◽  
S. M. SENKAN
Keyword(s):  
Activation Energies ◽  
Chlorinated Ethylenes ◽  
Pm3 Calculations

Deep level study in epitaxial 4H-SiC grown on substrates inclined toward

2002 ◽  
Vol 719 ◽  
Author(s):  
Masashi Kato ◽  
Masaya Ichimura ◽  
Eisuke Arai ◽  
Shigehiro Nishino
Keyword(s):  
Deep Level Transient Spectroscopy ◽  
Deep Level ◽  
Activation Energies ◽  
Thickness Dependence ◽  
Epitaxial Layers ◽  
Transient Spectroscopy

AbstractEpitaxial layers of 4H-SiC are grown on (0001) substrates inclined toward <1120> and <1100> directions. Defects in these films are characterized by deep level transient spectroscopy (DLTS) in order to clarify the dependence of concentrations and activation energies on substrate inclination. DLTS results show no such dependence on substrate inclination but show thickness dependence of the concentration.

Activation energies of technological termodonors in neutron doped silicon

2015 ◽  
Vol 19 (1/2) ◽  
Author(s):  
L. I. Panasjuk ◽  
V. V. Kolomoets ◽  
V. N. Ermakov ◽  
S. A. Fedosov ◽  
L. V. Yashchynskiy
Keyword(s):  
Activation Energies ◽  
Doped Silicon

Reductive transformation of tetrachloroethylene to ethylene and ethane by an anaerobic filter

1997 ◽  
Vol 36 (6-7) ◽  
pp. 125-132 ◽  
Author(s):  
Toshiya Komatsu ◽  
Jun Shinmyo ◽  
Kiyoshi Momonoi
Keyword(s):  
Electron Donor ◽  
Laboratory Scale ◽  
Groundwater Contaminants ◽  
Reductive Transformation ◽  
Filter System ◽  
Anaerobic Filter ◽  
Anaerobic Microorganisms ◽  
Chlorinated Ethylenes ◽  
Start Up ◽  
Low Concentrations

Tetrachloroethylene (PCE) is one of the most common groundwater contaminants in Japan. PCE can be completely dechlorinated to ethylene (ETY) and ethane (ETA) by anaerobic microorganisms in the presence of a suitable electron donor. This study was conducted to examine the feasibility of using an anaerobic filter for the degradation of PCE in a bioremediation process. Laboratory-scale anaerobic filters were operated at 25°C using ethanol as the electron donor. Rapid start-up of the reactors was achieved by using anaerobic completely PCE-dechlorinating enrichment cultures as the inoculum. During the continuous operating periods, low concentrations (2.8 mg/L) of PCE were almost completely dechlorinated to ETY and ETA at hydraulic retention times of 49-15 hours with 100 mgCOD/L of ethanol. PCE concentrations as high as 80 mg/L was dechlorinated to ETY with a relatively low supply (200 mgCOD/L) of ethanol. Results of this study suggest that the anaerobic filter system is a feasible bioremediation process for the cleanup of groundwater which is contaminated by chlorinated ethylenes.

Sterically Crowded Heterocycles. VII. Reduction of Some (Z)-1,3-Diphenyl-3-(2-phenylimidazo[1,2-a]pyridin-3-yl)prop-2-en-1-ones as Their Axial Chirality Probe

1996 ◽  
Vol 61 (7) ◽  
pp. 1018-1026 ◽  
Author(s):  
Richard Kubík ◽  
Stanislav Böhm ◽  
Josef Kuthan
Keyword(s):  
Hydroxy Derivative ◽  
Borohydride Reduction ◽  
Axial Chirality ◽  
Pm3 Calculations

Borohydride reduction of titled ketones 1a-1g gave diastereoisomeric mixtures of (Z)-1,3-diphenyl-3-(2-phenylimidazo[1,2-a]pyridin-3-yl)prop-2-en-1-ols 2a-2g and 3a-3g in which the former ones prevailed. Only individual racemic products were obtained after borohydride reduction of (E)-1,3-diphenyl-3-(2-phenylimidazo[1,2-a]pyridin-3-yl)-prop-2-en-1-one 4 to corresponding 1-hydroxy derivative 5 and by conversion of (Z)-1-oxo derivative 1a to 1,3-diphenyl-3-(2-phenylimidazo[1,2-a]pyridin-3-yl)propan-1-one (6) with sodium hydrogenselenide. Diastereoselectivity of the borohydride reduction is discussed using the PM3 calculations of the molecules 1a, 2a, 2b, 3a, 3b, 4, 5, and 6.

Kinetics of esterification of monoisopropylphenols with phosphoryl trichloride

1989 ◽  
Vol 54 (5) ◽  
pp. 1311-1317
Author(s):  
Miroslav Magura ◽  
Ján Vojtko ◽  
Ján Ilavský
Keyword(s):  
Liquid Phase ◽  
Rate Constants ◽  
Reaction Rates ◽  
Activation Energies ◽  
The Individual ◽  
Kinetics Of

The kinetics of liquid-phase isothermal esterification of POCl3 with 2-isopropylphenol and 4-isopropylphenol have been studied within the temperature intervals of 110 to 130 and 90 to 110 °C, respectively. The rate constants and activation energies of the individual steps of this three-step reaction have been calculated from the values measured. The reaction rates of the two isomers markedly differ: at 110 °C 4-isopropylphenol reacts faster by the factors of about 7 and 20 for k1 and k3, respectively. This finding can be utilized in preparation of mixed triaryl phosphates, since the alkylation mixture after reaction of phenol with propene contains an excess of 2-isopropylphenol over 4-isopropylphenol.

scholarly journals Machine learning meets mechanistic modelling for accurate prediction of experimental activation energies

2021 ◽  
Author(s):  
Kjell Jorner ◽  
Tore Brinck ◽  
Per-Ola Norrby ◽  
David Buttar
Keyword(s):  
Machine Learning ◽  
Activation Energies ◽  
Accurate Prediction ◽  
Nucleophilic Aromatic Substitution ◽  
Aromatic Substitution ◽  
Mechanistic Modelling

Hybrid reactivity models, combining mechanistic calculations and machine learning with descriptors, are used to predict barriers for nucleophilic aromatic substitution.

scholarly journals Migration of mineral oil in elastomers

2021 ◽  
Author(s):  
Tobias Förster ◽  
Artur Blivernitz
Keyword(s):  
Diffusion Coefficients ◽  
Mineral Oil ◽  
Activation Energies ◽  
Concentration Profiles ◽  
Small Reservoir ◽  
Experimental Procedure ◽  
Mineral Oils ◽  
The Absolute ◽  
Suitable Measure

AbstractThis work describes a newly introduced experimental procedure to quantify the diffusion progress of mineral oils locally resolved in NBR. Diffusion of reference oils IRM 901, IRM 902 and IRM 903 in NBR with various acrylonitrile contents was investigated. Classical sorption experiments were performed as a basic characterization and compared to the newly introduced method. Here, elastomer specimens are only being dipped with the bottom in a relatively small reservoir of mineral oil. This provides a determination of locally resolved concentration profiles of mineral oils, and the calculation of diffusion coefficients. These diffusion coefficients follow the same trends like those determined via sorption experiments. Despite differences in the absolute numbers, activation energies of diffusion can be applied as a suitable measure for the compatibility of elastomers and fluids.

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