Silicol process

Phosphine, which is produced in small quantities in the Silicol process for making hydrogen, has under certain conditions a deteriorating effect on cotton fabrics, not as an immediate action but as a secondary reaction. The examination of a balloon envelope which burst at Milan in 1906 showed that at some spots the material could be easily torn, while over the greater portion it... 

Remembering that the temperature of the caustic soda solution used in the silicol process is above 100" C., frequently rising to 120° C., it was thought that a higher temperature might perhaps produce the suspected reaction ferro-silicon was accordingly heated in an atmosphere of steam in an electric resistance furnace to a temperature of 300° C., but still no hydrogen was produced. Consequently it was concluded that the explanation of the smaller consumption of caustic soda than would be anticipated from theoretical considerations must be explained on some basis other than the reaction of silicon with water. 

The Silicon Content of the Perro SiIicon.— The grade of ferro-silicon used in this process is very important, as low-grade material does not yield anything like the theoretical quantity of hydrogen which should be obtained from the silicol present. This arises to a slight extent from the protective action of the impurities, which enclose particles of silicon and therefore prevent the caustic soda from attacking it. 

Since the caustic soda in the solution would be regenerated after it had reacted with the silicol, it would be available for reacting with yet more silicol, and would consequently reduce the quantity of caustic soda used in the process. 

Such organosiloxanes commonly are formed from the corresponding organosilanediols by a process of intermolecular condensation, as has been described in the discussion of the silicols ... 

Structure of silica colloids. Present ideas on the state of silica in aqueous solutions are examined in detail in the review by Sretenskaya (1970), where it is mentioned that one of the most typical features is the tendency to polymerize, i.e. to convert from a molecularly dispersed to a colloidally dispersed state. Polymerization is based on the process of condensation of silicol groups Si(OH)4 with liberation of water and as a result formation of the siloxane bonds Si-O-Si. 

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