ISSN:
0268-2605
Keywords:
Rochow reaction
;
cesium chloride
;
rubidium chloride
;
silicon impurities
;
action of promoters
;
scanning electron microscopy (SEM)
;
energy-dispersive X-ray spectroscopy (EDX)
;
Chemistry
;
Industrial Chemistry and Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Cesium chloride- and rubidium chloride-promoted Rochow contact masses based on both technical-grade and highly pure silicon have been investigated in the Rochow reaction and by REM/EDX surface analysis. The alkali-salt promoters seem to act analogously to the well-known zinc promoter, by localizing the reaction to distinct reactive areas and keeping free the surface area for the reaction, probably for the formation of catalytically active Cu-Si surface species. The alkali salts exhibited their promoting action only in combination with the impurities within the technical-grade silicon. Otherwise, they acted as blocking poisons. The promoter action of alkali chlorides in contact masses based on technical-grade silicon is possibly connected with the formation of salt melts, containing alkali chlorides and impurities. These melts, analogously to zinc chloride, could dissolve oxidic impurities from the silicon surface which otherwise would enhance the blocking of potentially active surface by extensive copper deposition. © 1998 John Wiley & Sons, Ltd.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
