KINETIC-STUDIES OF THE REACTION OF TETRAETHOXYSILANE WITH OXYGEN-ATOMS

The temperature dependent kinetics of the reaction of tetraethoxysilan e (TEOS) with O atom have been determined by fast flow reactor molecul ar beam sampling. The rate of constant has the form k = 3.4 x 10 (-11) exp (-1304 K/T) cm(3) s(-1) over the temperature range 300 to 673 K a nd similar to that of H atom abstraction from carbon-bonded ethoxy gro ups. Gas-phase products of the chemistry have been analyzed which sugg est that following formation of the primary radical, subsequent reacti ons lead to the formation of R3SiO and/or RnSi(OH)(4-n) (n < 4). These species are believed to undergo both four center elimination of ethyl ene and addition reactions to produce Si-O-Si ligands by dehydration.