Addition of metbyl radicals to ethylene and acetylene has been studwd by nb mitio molecular-orbital calculauons In agreemen! with expcrimenlal dam, we find that, although addition IO ethylene is charactenred by a lower activation energy. addition LO acetylene is faster due to the opposile and larger
Addition of atomic hydrogen to acetylene. Chain reactions of the vinyl radical
โ Scribed by Anthony B. Callear; Geoffrey Benedict Smith
- Publisher
- Elsevier Science
- Year
- 1984
- Tongue
- English
- Weight
- 382 KB
- Volume
- 105
- Category
- Article
- ISSN
- 0009-2614
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โฆ Synopsis
The mun reaction products resulting from the addition of ~tomrc hydrogen to acetylene are shown to be ethylene, l&butadiene, and benzene_ The mechankm mvolves chain reactions of the vinyl and butadienyl radrals, which regenemte atomic hydrogen_ Some of the rate psrameters are estimated
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The reactions have been studied by a mass-balance method involving the photolysis of small amounts of biacetyl in the presence of a large excess of isobutane containing a small proportion of the unsaturated substrate. The following Arrhenius parameters have been derived: Temperature Reaction E log A
The reaction of (2S,Ss)-0t-(I-hydroxyethyl)vinyl sulfoxide with alkyl radicals and tributyltin hydride gave the addition-hydrogenation products with high diastereoselectivity, whereas (2R,Ss)-~-( Ihydroxyethyl)vinyl sulfoxide gave no products under similar conditions. An important role of intramolec