Anhydrous n-hexane (50 L) was cooled to 20 1C, and
MeNH2 (5.82 kg, 187.55 mol) was condensed with the solvent.
A mixture of SiHCl3 (2.54 kg, 18.75 mol) and BCl3 (1.47 kg,
12.50 mol) in 12.5 L n-hexane was added dropwise to the
MeNH2/n-hexane solution at 15 1C for 2 h. The resulting
mixture was stirred at room temperature overnight. The
byproduct was filtered and the filtrate was collected and
condensed to give 1.7 kg of oligomer of polyborosilizane,
which was heated at 200 1C until an appropriate melt viscosity
was obtained.