Kinetics and mechanisms of the pyrolysis of diethyl ether I. The uninhibited reaction

The uninhibited thermal decomposition of diethyl ether was studied from 560 to 620 °C and at pressures ranging from 15 to 320 mmHg . The order of the overall reaction was between 1 and 3/2, the order being greater the higher the pressure. Analytical and kinetic data provide strong evidence that there is a molecular split of diethyl ether into ethanol and ethylene. The reaction leading to acetaldehyde and ethane, on the other hand, is concluded to be almost entirely a free-radical chain process. A detailed chain mechanism is postulated, involving first-order initiation and the reaction between C 2 H 5 and CH 2 CH 2 OC 2 H 5 as the chain-ending step. This mechanism is shown to give a steady-state rate equation which leads to first-order kinetics at lower ether pressures and three-halves-order kinetics at higher ones. The kinetic results lead to activation energies which are in satisfactory agreement with values calculated on the basis of the elementary reactions.

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The thermal decompositions of 2-methyl-2-phenoxypropane

Australian Journal of Chemistry ◽

10.1071/ch9810343 ◽

1981 ◽

Vol 34 (2) ◽

pp. 343 ◽

Cited By ~ 4

Author(s):

NJ Daly ◽

SA Robertson ◽

LP Steele

Keyword(s):

Gas Phase ◽

Reaction Mechanisms ◽

Arrhenius Equation ◽

Chain Process ◽

Quadrupole Mass ◽

Radical Chain ◽

Thermal Reactions ◽

First Order ◽

Radical Chain Process ◽

Good Agreement

The thermal reactions of 2-methyl-2-phenoxypropane have been studied in gas phase over the range 600-670 K by quadrupole mass spectrometry and pressure studies. The reaction is shown to be a homogeneous first-order elimination of phenol and 2-methylpropene which is described by the Arrhenius equation k = 1014.10�0.12exp[(-210.46�1.36)/RT] s-1 Possible reaction mechanisms are considered and the reaction is found to be a unimolecular elimination rather than a radical chain process initiated by homolysis to phenoxy and 1,1-dimethylethyl radicals. Evidence for the rearrangement to 4-t-butylphenol previously proposed has been carefully sought and it is concluded that the process does not occur in the gas phase. The A-factor observed for the reaction is in good agreement with that calculated for the four-centred transition state proposed for elimination of 2-methylpropene from alkoxypropanes.

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Metal ion initiated halogenation reactions of N-haloamines

Canadian Journal of Chemistry ◽

10.1139/v69-117 ◽

1969 ◽

Vol 47 (5) ◽

pp. 715-721 ◽

Cited By ~ 4

Author(s):

Dennis D. Tanner ◽

Melvyn W. Mosher

Keyword(s):

Metal Ion ◽

Cuprous Chloride ◽

Chain Process ◽

Chain Mechanism ◽

Molecular Chlorine ◽

Ferrous Chloride ◽

Radical Chain ◽

Acid Media ◽

Hydrocarbon Substrates ◽

Radical Chain Process

The metal ion catalyzed chlorination of hydrocarbon substrates by N-chloroamines and imides in acid media proceeds by a free radical chain mechanism. Reactions of four different N-chloro halogenating reagents with cuprous chloride, ferrous sulfate, and ferrous chloride initiators have been investigated. Contrary to the previously reported observations no experimental differences were observed in the halogenation reactions of individual N-halo compounds or with the different initiators. The chain carrying species in all cases was shown to be the chlorine atom and the radical chain process showed identical reactivity to that of photo-chlorination by molecular chlorine.

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