The addition of methyl radicals to ethylene, propylene, the butenes and higher 1-olefines

1957 ◽  
Vol 240 (1222) ◽  
pp. 396-407 ◽  
Keyword(s):  
Double Bond ◽  
Carbon Atom ◽  
Rate Constants ◽  
Relative Rate ◽  
Methyl Radicals ◽  
Active Hydrogen ◽  
Hydrogen Atoms ◽  
Methyl Group ◽  
Ethylene Propylene ◽  
Relative Rate Constants

The addition of methyl radicals to ethylene and its homologues in iso -octane solution was studied over the temperature range 55 to 85°C. The relative rate constants of addition to ethylene, propylene and iso -butene determined at 65°C are 34, 22 and 36 respectively. Taking into account the statistical factor of 2 for ethylene, we conclude that the increasing ease of addition for this series of olefines reflects the increasing stability of the produced radicals. The rates of addition to trans - and cis -butene-2 are significantly lower (6.9 and 3.4 respectively), indicating a steric hindrance resulting from the presence of a methyl group on the carbon atom on which the reaction takes place. Identical rates of addition were found for propylene, butene-1,pentene-1, 3 methyl butene-1, heptene-1, decene-1 and hexadecene-1, indicating that the rates of addition are not affected by the length and the shape of the hydro­carbon ‘tail’. The rates of abstraction of hydrogen atoms by methyl radicals were determined. It was found that the rate constants for active hydrogen ( α to C=C double bond) fall into three distinctive classes characterizing the primary, the secondary, and the tertiary hydrogen atoms.

Photooxidation of methyl ethyl ketone vapor

1967 ◽  
Vol 45 (22) ◽  
pp. 2741-2748 ◽  
Author(s):  
D. E. Hoare ◽  
D. A. Whytock
Keyword(s):  
Methyl Ethyl Ketone ◽  
Relative Rate ◽  
Quantum Yields ◽  
Methyl Ethyl ◽  
Hydrogen Atoms ◽  
Methyl Group ◽  
Ethyl Group ◽  
Relative Rate Constants ◽  
The Individual ◽  
Time Extrapolation

The photochemical reaction between methyl ethyl ketone and oxygen has been studied at 150 °C with light of 3 130 Å. Measurement of the quantum yields of the major products of the reaction indicates the chain nature of the reaction, the length of the chain decreasing with increase in time. Extrapolation of quantum yields of products to zero time allows the evaluation of several relative rate constants and at least an indication of the individual radical sources of the observed products. It is shown that abstraction of hydrogen atoms from the methyl group takes place at least at a quarter the rate of abstraction of a secondary hydrogen from the ethyl group at 150 °C. In the initial products the ethyl group gives mainly acetaldehyde or perpropionic acid, the methyl group gives formaldehyde and methanol, and the carbonyl group gives carbon dioxide and perpropionic acid with a little carbon monoxide.

The relative rate constants of oxygen, O(3P), atoms with different gaseous unsaturated compounds at room temperature

1986 ◽  
Vol 64 (9) ◽  
pp. 1925-1929 ◽  
Author(s):  
H. Deslauriers ◽  
G. J. Collin
Keyword(s):  
Double Bond ◽  
Rate Constants ◽  
Room Temperature ◽  
Relative Rate ◽  
Unsaturated Hydrocarbon ◽  
Ionization Potentials ◽  
Total Rate ◽  
Simple Method ◽  
Unsaturated Compounds ◽  
Relative Rate Constants

A simple method is proposed in order to measure the relative rate constants of the interactions between oxygen O(3P) atoms and unsaturated hydrocarbon. A 147 nm photolysis of air is used to produce the O(3P) atoms. In the presence of 1,2-butadiene, these oxygen atoms have a very clean reaction that gives rise to propylene formation. By including a suitable additive, and by looking at the formation of propene versus the [additive]/[1,2-butadiene] ratio, the absolute values of the various O(3P) + unsaturated hydrocarbon interactions can be evaluated. These rate constants increase with the number of substituents attached to the double bond. Moreover, a correlation between the total rate constants and ionization potentials is also observed.

Relative rate constants for abstraction of hydrogen by methyl radicals from ethane and from ethylene

1988 ◽  
Vol 66 (4) ◽  
pp. 578-583 ◽  
Author(s):  
S. I. Ahonkhai ◽  
M. H. Back
Keyword(s):  
Rate Constants ◽  
Relative Rate ◽  
Previous Measurement ◽  
Methyl Radicals ◽  
Lower Range ◽  
Thermal Reactions ◽  
Temperature Range ◽  
A Value ◽  
Relative Rate Constants

A method is described for the measurement of relative rate constants for abstraction of hydrogen by methyl radicals from ethane and from ethylene based on the effect of the addition of small quantities of ethane on the rates of formation of products in the thermal reactions of ethylene. The ratio of rate constants for reactions[Formula: see text]over the temperature range 673–733 K was given by the following expression:[Formula: see text](R = 1.987 cal mol−1 deg−1). Using a value of k4, from the literature the following expression was obtained for k3, over the same range of temperature:[Formula: see text]It was concluded that a previous measurement of k3 in a lower range of temperature was too close to the value of k4.

Kinetics of the successive chlorination of 1,2-dichloroethane in the liquid phase

1969 ◽  
Vol 22 (6) ◽  
pp. 1177 ◽  
Author(s):  
DS Caines ◽  
RB Paton ◽  
DA Williams ◽  
PR Wilkinson
Keyword(s):  
Liquid Phase ◽  
Rate Constants ◽  
Relative Rate ◽  
Stirred Tank ◽  
Continuous Stirred Tank Reactor ◽  
Alternative Pathways ◽  
Tank Reactor ◽  
Relative Rate Constants ◽  
Continuous Stirred Tank ◽  
Kinetics Of

Liquid 1,2-dichloroethane has been chlorinated by dissolved chlorine to a succession of chloroethanes up to the ultimate hexachloroethane. The results of both batch and continuous stirred tank reactor systems have been analysed by computer techniques to give a set of relative rate constants from which one can predict the product composition for a given chlorine uptake, the aim in this work being to optimize the production of tetrachloroethanes. An unusual feature of the kinetics is that 1,1,1,2- and 1,1,2,2-tetrachloroethanes provide alternative pathways between 1,1,2-trichloroethane and pentachloroethane.

RECOMBINATION OF OPPOSITELY CHARGED AQUEOUS CLUSTER IONS USING ELECTROSTATICALLY MERGED ION BEAMS

1996 ◽  
Vol 03 (01) ◽  
pp. 655-660 ◽  
Author(s):  
B. PLASTRIDGE ◽  
K.A. COWEN ◽  
D.A. WOOD ◽  
M.H. COHEN ◽  
J.V. COE
Keyword(s):  
Rate Constants ◽  
Cluster Size ◽  
Collision Energy ◽  
Relative Rate ◽  
Center Of Mass ◽  
Cluster Ions ◽  
Charged Cluster ◽  
Relative Rate Constants ◽  
Oppositely Charged ◽  
Electrostatic Quadrupole

A new method for studying cluster-cluster interactions is introduced which involves merging mass-selected beams of oppositely charged cluster ions with an electrostatic quadrupole deflector. Recombination is monitored by measuring the rate of fast neutral production. Relative rate constants have been measured for the reaction of H 3O+( H 2 O )n+ OH −( H 2 O )m as a function of cluster size (m=n=0–3), which display a pronounced enhancement with clustering. Relative rate constants have also been measured as a function of center-of-mass collision energy for a heavily clustered reaction (n=3, m=3) and a lightly clustered reaction (n=1, m=0) revealing that clustering produces a dramatic change in the reaction mechanism.

REACTION OF OXYGEN ATOMS WITH BUTADIENE

1960 ◽  
Vol 38 (11) ◽  
pp. 2187-2195 ◽  
Author(s):  
R. J. Cvetanović ◽  
L. C. Doyle
Keyword(s):  
Pressure Dependence ◽  
Rate Constants ◽  
Room Temperature ◽  
Relative Rate ◽  
Excess Energy ◽  
General Mechanism ◽  
Arrhenius Parameters ◽  
Heats Of Reaction ◽  
Relative Rate Constants ◽  
Oxygen Atoms

Reaction of oxygen atoms with 1,3-butadiene has been investigated at room temperature. It is found that it conforms to the general mechanism established previously for the analogous reactions of monoolefins. Only 1,2-addition occurs, and the addition products, butadiene monoxide and 3-butenal, possess excess energy when formed as a result of high heats of reaction. The pressure dependence of the formation of the addition products yields the values of the "lifetimes" of the initially produced "hot" molecules. The relative rate constants have been determined at 25 and 127 °C and from these the relative values of the Arrhenius parameters have been calculated.

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