Laser‐initiated chemical reactions: Cl+H2S→HCl+HS: Rate constant, product energy distribution, and direct detection of a chain mechanism

1978 ◽  
Vol 69 (2) ◽  
pp. 839-845 ◽  
Author(s):  
Martin Braithwaite ◽  
Stephen R. Leone
Keyword(s):  
Energy Distribution ◽  
Chemical Reactions ◽  
Rate Constant ◽  
Direct Detection ◽  
Chain Mechanism ◽  
A Chain

The expected time to attain chemical equilibrium from a thermodynamic probabilistic analysis

2012 ◽  
Vol 90 (3) ◽  
pp. 243-255
Author(s):  
Christopher Pastore ◽  
Moishe Garfinkle
Keyword(s):  
Experimental Data ◽  
Chemical Reactions ◽  
Chain Mechanism ◽  
Reaction Paths ◽  
Probabilistic Algorithm ◽  
Third Order ◽  
Expected Time ◽  
The Subject ◽  
A Chain ◽  
Stochastic Reaction

Employing a stochastic model, both Planck and Fokker proposed almost a century ago that stoichiometric chemical reactions proceed by a chain mechanism involving discrete reaction steps. To determine whether such a chain mechanism was in fact a valid mechanism for chemical reactions was the subject of a recent study (Garfinkle, M. 2002. J. Phys. Chem. 106A: 490). Using a thermodynamic–probabilistic algorithm the stochastic reaction paths were found to be in excellent agreement with the observed reaction paths plotted from experimental data. This study was then extended to test the conclusions of Ehrenfest and Prigogine that a chain mechanism dictates that the number of discrete reaction steps required for a chemical reaction to attain equilibrium must be finite. The stochastic and empirical reaction paths were compared using experimental data for first-, second-, and third-order reactions as well as fractional order reactions. The empirical verification was excellent.

THE KINETICS OF THE OXIDATION OF GASEOUS ACETALDEHYDE

1932 ◽  
Vol 7 (2) ◽  
pp. 149-161 ◽  
Author(s):  
W. H. Hatcher ◽  
E. W. R. Steacie ◽  
Frances Howland
Keyword(s):  
Carbon Dioxide ◽  
Formic Acid ◽  
Induction Period ◽  
Reaction Vessel ◽  
Oxidation Products ◽  
Main Reaction ◽  
Chain Mechanism ◽  
Subsequent Reaction ◽  
A Chain ◽  
Kinetics Of

The kinetics of the oxidation of gaseous acetaldehyde have been investigated from 60° to 120 °C. by observing the rate of pressure decrease in a system at constant volume. A considerable induction period exists, during which the main products of the reaction are carbon dioxide, water, and formic acid. The main reaction in the subsequent stages involves the formation of peroxides and their oxidation products. The heat of activation of the reaction is 8700 calories per gram molecule. The indications are that the reactions occurring during the induction period are heterogeneous. The subsequent reaction occurs by a chain mechanism. The chains are initiated at the walls of the reaction vessel, and are also largely broken at the walls.

Réactions ion–molécule dans les méthylbutènes: radiolyse du méthane

1976 ◽  
Vol 54 (4) ◽  
pp. 555-559
Author(s):  
Guy J. Collin
Keyword(s):  
Tertiary Structure ◽  
Ionic Mechanism ◽  
Chain Mechanism ◽  
A Chain

The radiolysis of gaseous methane has been studied in the presence of one of the three methylbutenes. We have observed an important isomerization of the added olefin. An ionic mechanism initiated by the CH5+ and C2H5+ ions seems to be compatible with the observations reported. Isomerization proceeds through a chain mechanism where the chain carrier may be the tert-C5H11+ ion. In the presence of 3-methyl-1-butene, the initially formed (CH3)2CHCHCH3+ ion isomerizes to the tertiary structure before producing the observed isomerization.

scholarly journals On apparent barrier-free reactions

2020 ◽  
Vol 3 (1) ◽  
pp. 3-8
Author(s):  
Maikel Ballester
Keyword(s):  
Low Temperature ◽  
Chemical Reactions ◽  
Rate Constant ◽  
Kinetic Models ◽  
Rate Coefficient ◽  
Minimum Energy ◽  
Temperature Limit ◽  
Rate Coefficients ◽  
Minimum Energy Path ◽  
Full Dimension

Rate coefficients of bi-molecular chemical reactions are fundamental for kinetic models. The rate coefficient dependence on temperature is commonly extracted from the analyses of the reaction minimum energy path. However, a full dimension study of the same reaction may suggest a different asymptotic low-temperature limit in the rate constant than the obtained from the energetic profile.

Rate Constant of Solid-Phase Chemical Reactions. Theory

2021 ◽  
pp. 68-131
Author(s):  
V.I. Gol’danskii ◽  
L.I. Trakhtenberg ◽  
V.N. Fleurov
Keyword(s):  
Chemical Reactions ◽  
Rate Constant ◽  
Solid Phase ◽  
Phase Chemical

γ-Radiosensitized isomerization of gaseous butenes and methylbutenes

1980 ◽  
Vol 58 (18) ◽  
pp. 1973-1978 ◽  
Author(s):  
Guy J. Collin ◽  
Jan A. Herman
Keyword(s):  
Noble Gas ◽  
Chain Mechanism ◽  
Reverse Effect ◽  
A Chain

We have studied the isomerization of butenes and methylbutenes by noble gas-sensitized radiolysis. The isomerization of isobutene to but-2-ene is more efficient in the presence of xenon than in the presence of krypton or argon. The isomerization of but-1-ene into isobutene has a low radiolytic yield and occurs only in the presence of small quantities of dimethylamine. These observations are in agreement with the isomerization of the excited parent ion.In the methylbutene systems, whatever the sensitizing agent, isomerization occurs with a high radiolytic yield. Thus, a chain mechanism is needed to explain the results. The addition of dimethylamine has a reverse effect relative to that observed in but-1-ene. It is concluded that the mechanism invoked for the butene systems is not adequate for explaining the isomerization observed in the methylbutene systems.

The gaseous oxidation of aliphatic alcohols. III. n - and iso -propyl alcohols

1960 ◽  
Vol 257 (1290) ◽  
pp. 402-412 ◽  
Keyword(s):  
Hydrogen Peroxide ◽  
Carbon Monoxide ◽  
Free Radicals ◽  
Induction Period ◽  
Isopropyl Alcohol ◽  
Side Reactions ◽  
Chain Mechanism ◽  
Complete Elimination ◽  
Chain Branching ◽  
A Chain

A study of the gaseous oxidation of n -propyl alcohol (1-propanol) at 264°C shows that, after an induction period during which higher aldehydes and hydrogen peroxide are apparently the only products formed, the pressure starts to rise autocatalytically and methanol, formaldehyde and carbon monoxide become detectable. Additions of higher aldehydes reduce the induction period but the amounts required for its complete elimination are considerably greater than those normally present at the end of the induction period. A chain mechanism is proposed which involves initially abstraction of hydrogen from 1-propanol by HO 2 radicals followed by interaction of the resulting hydroxypropyl radicals with oxygen to yield propionaldehyde. Further reactions of this aldehyde are believed to be responsible for chain-branching and for the formation of the various C 1 products. Isopropyl alcohol (2-propanol) is much less readily oxidized than 1-propanol. At 330°C the main oxidation product is acetone which is formed together with hydrogen peroxide in somewhat smaller quantities. Minor products include methanol, acetaldehyde and formaldehyde. The course of the oxidation of 2-propanol is little affected by additions of acetone or formaldehyde but the induction period is markedly reduced by added acetaldehyde. The chain cycle suggested for the initial stages of oxidation involves attack by HO 2 radicals at the tertiary C─H bond of the alcohol followed by reaction of the resulting free radicals with oxygen to give acetone. The intermediate responsible for chain-branching is believed to be acetaldehyde which is produced by side reactions. C 1 compounds are formed partly by oxidation of this aldehyde and partly by further reactions of acetone.

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