Polar radicals. XI. Kinetic studies on the mechanism of the liquid phase bromination of 1-chlorobutane

1977 ◽  
Vol 55 (20) ◽  
pp. 3536-3543 ◽  
Author(s):  
Dennis D. Tanner ◽  
Tameichi Ochiai ◽  
Jeff Rowe ◽  
Tony Paċe ◽  
Hideki Takiguchi ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Hydrogen Bromide ◽  
Kinetic Studies ◽  
Solution Phase ◽  
Transfer Reactions ◽  
Substituted Alkanes ◽  
Kinetics Of ◽  
Reversible Transfer ◽  
General Method

A general method for the evaluation of the kinetics of the solution phase bromination of alkanes and substituted alkanes is presented. The model used considers reversible transfer reactions of the radicals formed with both hydrogen bromide and hydrogen tribromide. Cage reversal of the geminate radical – hydrogen bromide pair and reversal with hydrogen tribromide are used to rationalize the differences observed between the vapor and solution phase kinetics.The method is applied to the bromination of 1-chlorobutane.

Polar Radicals. VIII. Kinetic Studies on the Mechanism of the Vapor Phase Bromination of 1-Chlorobutane. The Role of Reversible Hydrogen Abstraction

1975 ◽  
Vol 53 (14) ◽  
pp. 2202-2209 ◽  
Author(s):  
Dennis D. Tanner ◽  
Tony Pace ◽  
Tameichi Ochiai
Keyword(s):  
Vapor Phase ◽  
Hydrogen Bromide ◽  
Hydrogen Abstraction ◽  
Kinetic Studies ◽  
Abstraction Reaction ◽  
Substituted Alkanes ◽  
Kinetics Of ◽  
Hydrogen Abstraction Reaction ◽  
General Method

A general method for the evaluation of the kinetics of the vapor phase brominations of alkanes and substituted alkanes is presented. The method is applied to the bromination of 1-chlrobutane.The hydrogen abstraction reaction and its reversal are both found to be deactivated by the polar influence of the substituent; the effect, as predicted, falls off as the distance of the substituent from the C—H bond involved increases. In the vapor phase bromination of 1-chlorobutane, because of this deactivated reversal, transfer with hydrogen bromide cannot compete (< 10%) with transfer with molecular bromine.There was no evidence for anchimeric assistance by the neighboring chlorine atom during hydrogen abstraction.

Thermodynamics and Kinetic Considerations behind the Growth of AlN Whiskers Synthesized by Carbothermal Reduction

2007 ◽  
Vol 280-283 ◽  
pp. 1403-1408 ◽  
Author(s):  
Ren Li Fu ◽  
He Ping Zhou ◽  
Ke Xin Chen ◽  
José Maria F. Ferreira
Keyword(s):  
Melting Point ◽  
Liquid Phase ◽  
Carbothermal Reduction ◽  
Solid Phase ◽  
Dominant Role ◽  
Kinetic Studies ◽  
Synthesis Temperature ◽  
Screw Dislocations ◽  
Melting Point Eutectic ◽  
Kinetics Of

AlN whiskers have been successfully synthesized by carbothermal reduction. The thermodynamics and growth kinetics of AlN whiskers were studied at 1600°C using CaCO3 as a catalyst. The research indicated that AlN whiskers are more easily nucleated from the liquid phase than at the surface of solid phase. AlN whiskers are nucleated by VLS mechanism and the liquid, which plays a dominant role in the VLS mechanism, is formed by Al-Ca interphases, such as CaO×2Al2O3 and CaO×6Al2O3. Kinetic studies suggest that the catalyst reacts with Al2O3 to form a low melting point eutectic (1390°C). The liquid phase formed at this low melting point eutectic provides good conditions for nucleation of AlN whiskers. At the synthesis temperature, the liquid phase vaporizes, thus creating suitable conditions for the subsequent growing of whiskers by the VLS mechanism. This growing mechanism conforms to thermodynamics and a lot of proof indicates that screw dislocations play an important role in the process of the whiskers' formation.

Effect of ionizing radiation on the kinetics of hydrogenation on the Ni-MgO mixed catalyst

1982 ◽  
Vol 47 (7) ◽  
pp. 1780-1786 ◽  
Author(s):  
Rostislav Kudláček ◽  
Jan Lokoč
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Liquid Phase ◽  
Ionizing Radiation ◽  
Oxide Catalyst ◽  
Absorbed Dose ◽  
Hydrogenation Rate ◽  
Solution Composition ◽  
Mixed Catalyst ◽  
Kinetics Of

The effect of gamma pre-irradiation of the mixed nickel-magnesium oxide catalyst on the kinetics of hydrogenation of maleic acid in the liquid phase has been studied. The changes of the hydrogenation rate are compared with the changes of the adsorbed amount of the acid and with the changes of the solution composition, activation energy, and absorbed dose of the ionizing radiation. From this comparison and from the interpretation of the experimental data it can be deduced that two types of centers can be distinguished on the surface of the catalyst under study, namely the sorption centres for the acid and hydrogen and the reaction centres.

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.

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