Flash Vacuum Pyrolysis (FVP) of 2,7-Dimethyl-2,3:7,8-diepoxy-5-silaspiro(4.4)nonane (I) with Cyclotrisiloxanes-Synthesis of Spirocyclosiloxanes. Characterization of Silica Formed by FVP of I

摘要

Flash vacuum pyrolysis of 2,7-dimethyl 12,3:7,8-diepoxy-5-silaspiro nonane (I) with cyclortrisiloxanes yields 2,4,6,8,10,12,14-heptasila-1m3,5m7m9m11m13-15-octaozaspiro pentadecanes (III) and 2,4,6,8,10,12,14,17-octasila-1,3,5,7,9,11,13,15,16,18-decaoxadispiro 5.3.5.3 octadecenes (IV). These spirocyclosilozanes may result from the insection of oxygen silicon oxygen double bonds of an equivalent synthon into the silicon-oxygen single bond of the trapping regnets. the structures of these have been determined by 1hydrogen, 13carbon, in particular, 29silicon MNR. The structure of IVa has been confirmed by X-ray crystallography. In the absence of trapping agents silicon dioxide of high surface areas is deposited. This material has been characterized by scanning and transmission electron microscopy. Keywords: Flash vacuum pyrolysis; Spiro siloxanes, Silica.