Kinetics of methylchlorosilane formation on Zn-promoted Cu3Si

✍ Scribed by J. P. Agarwala; John L. Falconer

• Book ID: 102928856
• Publisher: John Wiley and Sons
• Year: 1987
• Tongue: English
• Weight: 687 KB
• Volume: 19
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550190605

✦ Synopsis

The kinetics of the direct synthesis reaction (Si + 2CH,CI --f (CH&3iCla) were measured on a Cu,Si alloy containing 1.2 atom % Zn. Reaction was carried out in a differential reactor (520-595 K, 1 atm) attached to an ultrahigh vacuum (UHV) system.

Auger spectroscopy was used to characterize the surface before and after reaction. Zinc does not significantly change the overall rate of reaction, but it changes selectivity to dimethyldichlorosilane (the desired product), surface composition, activation energies, and induction times. The rate of silicon diffusion to the surface is not limiting in the presence of zinc. Zinc is found to be a promoter for improved selectivity only in low concentrations, and only a fraction of the surface appears to be active for reaction. The kinetics appear relatively insensitive to the surface composition or the form of surface carbon. A CusSi surface with Zn is shown to be a good model catalyst for the direct synthesis reaction.