Oberflächenverbindungen von Übergangsmetallen, XXII [1]. Die Umsetzung von Oberflächen-Chrom(II) auf Silicagel mit Olefinen bei höherer Temperatur. - Zum Mechanismus von Aufbau-, Abbau-, Metathese- und Isomerisierungs-Reaktionen an koordinativ ungesättigten Oberflächen-Metallionen / Surface Compounds of Transition Metal, XXII [1]. The Reaction of Surface Chromium(II) on Silica with Olefins at Higher Temperature. - A Contribution to the Mechanism of Growth, Degradation, Metathesis and Isomerization on Coordinatively Unsaturated Surface Metal Ions
Open Access
- 1 December 1979
- journal article
- Published by Walter de Gruyter GmbH in Zeitschrift für Naturforschung B
- Vol. 34 (12) , 1628-1636
- https://doi.org/10.1515/znb-1979-1202
Abstract
With chromium(II) supported on silica, at T > 150 °C olefins undergo growth/degradation/metathesis reactions by addition/elimination of even and uneven chain fragments including Ci. Simultaneously, catalytic double bond isomerization and C-rearrangements to methyl branched olefins occur. One mechanism is proposed for all these reactions via a pseudo-tetrahedral MC3 intermediate. Polyethylene synthesis at lower temperatures may follow the same way. For growth/degradation/metathesis the formation of a metal carbene unit is postulated as a characteristic, step; in case of ethylene, >Cr=CH2 will be formed as a precursor of the final CH4 (resulting from a secondary reaction with support hydrogen).Keywords
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