Hydrochloric Acid → Silicon tetrachloride

Participants

Reaction Steps

70 ml/h of high-boiling residue from the silane synthesis having a boiling point of greater than 150° C. and 25 I/h of gaseous hydrogen chloride were fed concurrently at room temperature and ambient pressure into an electrically heated laboratory fluidized-bed reactor having a length of 500 mm and an internal diameter of 40 mm, filled with 266 g of silicon, d(0.5): 70-80 μm. The temperature was set to 600° C. The high-boiling residue comprised 75 % of disilanes, a mixture of tetrachlorodimethyldisilane, trichlorotrimethyldisilane, dichlorotetramethyldisilane and other silanes. A more precise assignment was difficult because of the large number of by-products. After 20 hours of operation, the experiment was stopped without deposits having been formed. About 100 g/h of silane mixture comprising, as main constituents, about 20 % of trichlorosilane and about 40% of silicon tetrachloride was formed. After separation of the trichlorosilane and silicon tetrachloride, a silane cleavage product having the composition set forth in Table 1 was obtained during the experiment.

Provenance & Evidence