Kinetic study for the reactions of chlorine atoms with hexamethyldisiloxane, 1,1,3,3-tetramethyldisiloxane, and 1,3-dimethyldisiloxane

Abstract

The absolute rate constants for the reactions of chlorine atoms with (CH 3) 3SiOSi(CH 3) 3, (CH 3) 2HSiOSiH(CH 3) 2, and (CH 3)H 2SiOSiH 2(CH 3) were measured in the gas phase over the temperature range 273–363 K, using the very low pressure reactor (VLPR) in a molecular flow system. The absolute rate constants were temperature independent and take the values (in cm 3 molecule −1 s −1 , 2 σ uncertainties): k 1=(1.00±0.19)×10 −10, k 2=(1.98±0.29)×10 −10 , and k 3=(2.42±0.25)×10 −10. All title reactions proceed via the abstraction of C–H and/or Si–H hydrogen leading to the formation of HCl. The results show that the reactivity of Si–H bond towards Cl atom attack is higher than the reactivity of the C–H bond.