Temperature dependent rate constant for the reaction of H‐atoms with carbonyl sulfide

Abstract

The kinetics of the reaction of H‐atom with carbonyl sulfide (OCS) has been investigated at nearly 2 Torr total pressure of helium over a wide temperature range, T = 255–960 K, using a low‐pressure discharge flow reactor combined with an electron impact ionization quadrupole mass spectrometer. The rate constant of the reaction H + OCS → SH + CO (1) was determined under pseudo‐first order conditions, monitoring the kinetics of H‐atom consumption in excess of OCS, k1 = 6.6 × 10−13 × (T/298)3 × exp(−1150/T) cm3 molecule−1 s−1 (with estimated total uncertainty on k1 of 15% at all temperatures). Current measurements of k1 at intermediate temperatures (520–960 K) appear to reconcile previous high and low temperature data and allow the above expression for k1 to be recommended for use in the extended temperature range between 255 and 1830 K with a conservative uncertainty of 20%.

Experimental Study of the Reaction of OH Radicals with Carbonyl Sulfide between 365 and 960 K: Kinetics and Products

“…Experiments were carried out in a standard-design discharge flow reactor combined with a mass spectrometric analysis (quadrupole mass spectrometer Balzers, QMG 420 with electron impact ionization) of the chemical composition of the reactive system [13,14]. The reactor consisted of a quartz tube (45 cm in length, 2.5 cm i.d.…”

“…k 12 = 6.6 × 10 −13 (T/298) 3 exp(−1150/T) cm 3 molecule −1 s −1 (T = 255-1830 K) [13]. However, it should be noted that in the measurements of k 1 at high temperatures, we have not observed any evidence for this OH regeneration: The OH decays were exponential, and the rate of OH consumption did not slow down with the reaction time; at sufficiently high concentrations of OCS, the total consumption of OH was observed.…”