A Cu-catalyzed reaction procedure was found for the selective formation of dimethylchlorosilane [(CH3)2HSiCl] from the direct reaction of CH3Cl with solid Si. The new procedure is a two-step process. A Cu/Si sample is prepared by evaporating Cu onto clean polycrystalline Si under ultrahigh vacuum, and the Cu/Si surface is first activated by exposure to 10% HSiCl3/CH3Cl at 598 K. After the HSiCl3/CH3Cl mixture is evacuated from the reactor, the activated Cu/Si surface is reacted in fresh CH3Cl. For low surface concentrations of Cu, the partially hydrogenated silane, (CH3)2HSiCl, is selectively produced. Trichlorosilane was also found to activate polycrystalline Si (in the absence of Cu) for production of highly chlorinated methylchlorosilanes at a much higher rate than on the Cu/Si surface but with poor selectivity to (CH3)2HSiCl. All reactions are carried out at atmospheric pressure in a reactor that is attached to an ultrahigh-vacuum chamber. This allows surface analysis by Auger electron spectroscopy, which detected SiClx on reacted surfaces. These SiClx sites, which appear necessary for methylchlorosilane formation, are apparently formed during activation by HSiCl3.
|Original language||English (US)|
|Number of pages||6|
|Journal||Journal of physical chemistry|
|State||Published - Dec 1 1989|
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry