Role of reversible hydrogen abstraction in the mechanism of the bromination of cyclohexane. Comparison of the differences between the liquid and vapor phase reactions

1975 ◽  
Vol 97 (15) ◽  
pp. 4303-4307 ◽  
Author(s):  
Dennis D. Tanner ◽  
Tony Pace ◽  
Tameichi Ochiai
Keyword(s):  
Vapor Phase ◽  
Hydrogen Abstraction

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.

Role of Vapor Phase in Oxidation/Combustion Kinetics of High-Pressure Air Injection (HPAI)

2010 ◽  
Author(s):  
Yalda Barzin ◽  
Robert Gordon Moore ◽  
Sudarshan A. Mehta ◽  
Don G. Mallory ◽  
Matthew G. Ursenbach ◽  
...  
Keyword(s):  
High Pressure ◽  
Vapor Phase ◽  
Air Injection ◽  
Combustion Kinetics ◽  
Kinetics Of

Detailed kinetics of hydrogen abstraction from trans-decalin by OH radicals: the role of hindered internal rotation treatment

2020 ◽  
Vol 22 (44) ◽  
pp. 25740-25746
Author(s):  
Tam V.-T. Mai ◽  
Lam K. Huynh
Keyword(s):  
Master Equation ◽  
Hydrogen Abstraction ◽  
Kinetic Mechanism ◽  
Oh Radicals ◽  
Rate Model ◽  
Wide Range ◽  
Detailed Kinetics ◽  
Kinetics Of ◽  
Detailed Kinetic Mechanism

The detailed kinetic mechanism of the trans-decalin + OH reaction is firstly investigated for a wide range of conditions (T = 200–2000 K & P = 0.76–76000 Torr) using the M06-2X/aug-cc-pVTZ level and stochastic RRKM-based Master equation rate model.

scholarly journals Isotopic diffusion in polycrystalline ice

2003 ◽  
Vol 49 (166) ◽  
pp. 397-406 ◽  
Author(s):  
Alan W. Rempel ◽  
J. S. Wettlaufer
Keyword(s):  
Stable Isotopes ◽  
Stable Isotope ◽  
Vapor Phase ◽  
High Frequency ◽  
Ice Core ◽  
Accurate Analysis ◽  
Depositional Processes ◽  
Polycrystalline Ice ◽  
End Members

AbstractQuantitative ice-core paleoclimatology must account for post-depositional processes, such as vapor-phase diffusion in the firn. After pore close-off, diffusion continues to smooth the stable-isotope records δ18O and δD that are eventually recovered from the ice, leading to the loss of high-frequency information. Johnsen and others (1997) found much higher rates of diffusive smoothing in the Greenland Icecore Project (GRIP) Holocene ice than would be predicted by diffusion through solid ice alone, and Nye (1998) argued that transport through liquid veins might explain this apparent excess diffusion. However, the analysis of Johnsen and others (2000) indicates that the required vein dimensions may be unrealistically large. Here, we model the diffusion of stable isotopes in polycrystalline ice and show that the predictions of Nye (1998) and those of Johnsen and others (2000) actually represent two end-members in a range of potential behavior. Our model determines which of these asymptotic regimes more closely resembles the prevailing conditions and quantifies the role of pre-melted liquid in the smoothing of isotopic signals. The procedure thereby ties together the two approaches and provides a rostrum for accurate analysis of isotope records and paleotemperature reconstructions.

Impact of water on the BrO + HO2 gas-phase reaction: mechanism, kinetics and products

2019 ◽  
Vol 21 (36) ◽  
pp. 20296-20307 ◽  
Author(s):  
Narcisse T. Tsona ◽  
Shanshan Tang ◽  
Lin Du
Keyword(s):  
Reaction Mechanism ◽  
Gas Phase ◽  
Hydrogen Abstraction ◽  
Phase Reaction ◽  
Gas Phase Reaction

The role of water in preventing the barrierless hydrogen abstraction in the BrO + HO2 reaction is highlighted.

Vapor-Phase Catalyst Delivery Method for Growing SiC Nanowires

2013 ◽  
Vol 740-742 ◽  
pp. 209-212 ◽  
Author(s):  
Rooban Venkatesh K.G. Thirumalai ◽  
Bharat Krishnan ◽  
Albert Davydov ◽  
Joseph Neil Merrett ◽  
Yaroslav Koshka
Keyword(s):  
Vapor Phase ◽  
Gas Flow ◽  
Substrate Surface ◽  
Metal Catalyst ◽  
Catalyst Nanoparticles ◽  
Sic Nanowires ◽  
Cvd Growth ◽  
Hot Zone

A method was developed for growing SiC nanowires without depositing a metal catalyst on the targeted surfaces prior to the CVD growth. The proposed method utilizes in-situ vapor-phase catalyst delivery via sublimation of the catalyst from a metal source placed in the hot zone of the CVD reactor, followed by condensation of the catalyst-rich vapor on the bare substrate surface to form the catalyst nanoparticles. The vapor-phase catalyst delivery and the resulting nanowire density was found to be influenced by both the gas flow rate and the catalyst diffusion through the boundary layer above the catalyst source. The origin of undesirable bushes of nanowires and the role of the C/Si ratio were established.

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