ABSTRACT
Shock-tube experiments were conducted to determine rate-coefficient data of the H-atom abstraction reactions H + HMDSO (hexamethyldisiloxane) → H2 + HMDSO−H and H + TMDSO (tetramethyldisiloxane) → H2 + TMDSO−H. The experiments comprised a temperature range of 1109–1240 K and pressures between 1.2 and 1.5 bar. In all experiments, C2H5I was used as a precursor for H atoms. H-atom concentrations were measured with atomic resonance absorption spectrometry (ARAS) and rate-coefficient data were obtained from pseudo-first-order analysis of temporal H-atom concentration profiles. Experimental total rate-coefficients were well represented by the following Arrhenius equations: ktotal,HMDSO(T) = 10−9.49±0.36 exp(−32.4 ± 8.1 kJmol−1/RT) cm3molecule−1s−1 for H + HMDSO and ktotal,TMDSO(T) = 10−8.00±0.36 exp(−53.3 ± 7.9 kJ mol−1/RT) cm3molecule−1s−1 for H + TMDSO. Multiple reaction channels were explored by computations at G4//B3lyp-D3BJ level of theory.
GRAPHICAL ABSTRACT
Acknowledgements
The authors thank Prof. Jürgen Wolfrum (PCI, University of Heidelberg) for stimulating discussions.
Disclosure statement
No potential conflict of interest was reported by the author(s).