Dynamic properties of n-alkyl and s-alkyl intermediates in reactions of simple alkenes with hydrogen on MoS2 catalyst
- 1 January 1979
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases
- Vol. 75, 7-21
- https://doi.org/10.1039/f19797500007
Abstract
The hydrogen exchange between (Z)-[1-2H1]propene, [graphic omitted], and [2H6]propene taking place on MoS2 in the presence of hydrogen yielded a variety of deuteropropene isomers in the relative proportions 7.5%[1,1-2H2], 4.5%(Z)-[1,2-2H2], 34.0%(E)-[1,2-2H2], 51.0%(E)-[1-2H1], 0%[2-2H1] and 3%[2H0]propene in the initial stage of the exchange reaction at room temperature. This distribution was in good agreement with calculations based on a relative contribution of 70% n-propyl and 30% isopropyl intermediates determined by a separate experiment, and the relative contributions of the n-alkyl and s-alkyl intermediates were found to be the same for the hydrogen exchange reaction of but-1-ene. The hydrogen addition and elimination processes in the isomerization reaction as well as in the hydrogen exchange of olefins are strictly controlled by a cis-stereo specificity of the site which has one coordination vacancy, [graphic omitted]. The s-alkyl species formed on this site are restricted from free rotation around the coordination bond by steric interaction with the surrounding sulphur ions. Such dynamic properties of the s-alkyl intermediates give unexpectedly low values for [3-2H1]propene: [1-2H1]propene of 2 requires two vacancies.Keywords
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