The kinetics of the gas-phase reaction between iodine and phenylsilane and the bond dissociation energy D(C6H5SiH2H)

✍ Scribed by M. Barber; A. M. Doncaster; R. Walsh

• Publisher: John Wiley and Sons
• Year: 1982
• Tongue: English
• Weight: 418 KB
• Volume: 14
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550140609

✦ Synopsis

The title reaction has been investigated in the temperature range of 490-573 K. Initial reactant pressures were varied in the range of 0.2-5.2 torr (12) and 2-20 torr (C&,SiH3). The rate of iodine consumption, monitored spectrophotometrically, was found to obey

both by initial rate and integrated equation fitting procedures. The effect of added initial HI conformed to this expression. The data are consistent with a conventional I-atom propagated chain reaction, and for the step I' + C&SiH3 -CEH5SiHz + HI the rate constant is given by log k l (dm3/mol. s) = (11.52 f 0.08) -(76.8 f 0.8 kJ/mol)/RT In 10 From this is derived the bond dissociation energy value D(CsH5SiH2-H) = 374 kJ/mol(88 kcal/mol). A comparison with other Si-H dissociation energy values indicates that the "silabenzyl" stabilization energy is small, =7 kJ/mol.