METHOD OF OBTAINING HIGH PURITY MONOSILANE AND POLYCRYSTALLINE SILICON Russian patent published in 2008 - IPC C01B33/04 C01B33/29 

FIELD: chemistry.

SUBSTANCE: industrial silicon with industrial methanol react in the presence of a catalyst at high temperature. From the products of the reaction, hydrogen-containing methoxysilane in a mixture with tetramethoxysilane is separated. Monosilane is obtained through catalyst disproportioning of hydrogen-containing methoxysilanes, and cleaned through adsorption on active carbon. Temperature fall between the stages of separating hydrogen-containing methoxysilanes and subsequent catalyst disproportioning does not decrease by less than 60°C. Purifying monosilane from carbon-containing impurities is done through throttle discharge of monosilane from high pressure of 60 kg/cm² to low pressure of 1-3 kg/cm², providing for lowering temperature of gaseous monosilane with impurities to temperature not higher than minus 10°C and formation of a dispersed phase of tetramethoxysilane. Through hydrolysis of tetramethoxysilane, silicon dioxide is obtained, which is reduced to silicon and returned to the stage of direct synthesis of trimethoxysilane.

EFFECT: lower content of carbon-containing impurities in monosilane and low consumption of raw materials and energy.

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