Exchange reactions of CD2CH—CH3, in the absence of gaseous deuterium, over magnesia and rutile investigated by microwave spectroscopy

Abstract

Mass spectrometry and microwave spectroscopy have been used to study the reactions of CD₂CH—CH₃ over magnesia at 195 K and over rutile at 453 K. The rates of production of [²H₁]propene and [²H₃]propene have been measured. In addition, double bond shift and deuterium scrambling of the reactant and products have been investigated. The relative rates of these processes on these oxides have been analysed to provide further evidence for the mechanism of propene exchange with gaseous deuterium and the surface intermediates involved. Double bond shift of propene is found to be fast on both catalysts under the experimental conditions but, whereas it is deduced to proceed almost exclusively by an intermolecular mechanism on magnesia, an intramolecular mechanism seems important on rutile.