Rate Constants of the Reactions of CHCl (X̃¹A′) with Ethylene, Propylene, and Acetylene

Abstract

The rate constants of the reactions of CHCl (X̃1A′) with C2H2 (k4), C2H4 (k5) and C3H6 (k6) were measured as a function of temperature. Experiments were carried out under quasistationary conditions at around 18.5 mbar total pressure. It is shown that excimer laser photolysis of CF2 = CHCl at λPH = 193 nm is a suitable source for CHCl (X̃1A′) generation. The following rate constants were obtained from logarithm plots: k4 = (4.2±0.1)·1012 (T/295K)−(0.79±0.06) cm3 mol−1 s−1 k5 = (3.2±0.2)·1012 (T/295 K)−(1.52±0.12) cm3 mol−1 s−1 k6 = (8.3±1.4)·1012 (T/295 K)−(1.39±0.05) cm3 mol−1 s−1 The reactivity of CHCl (X̃1A′) is compared to those of other carbenes.

Fluorescence excitation spectroscopy of the system of jet-cooled HCCl in the region 5150–6050Å

“…Several studies have examined the kinetics of HCCl reactions using laser induced fluorescence [22][23][24]; however, to our knowledge no systematic measurement of the fluorescence lifetimes has ever been performed. The lifetimes of the bands measured in this work, averaged over rotational level, are given in Table 3, and plotted in Fig.…”

Halocarbenes May Deplete Atmospheric Ozone

“…CHF and CH 2 , both very electrophilic carbenes, have negative activation energies in reactions with O 3 and CHF can form an intermediate complex with O 3 [92]. Reactions of CHCl with NO and O 2 [93] and ethylene, propylene and acetylene [94] have been studied, but apparently not with O 3 .…”

Kinetics of HCCl + NOx reactions

“…Although this species has been characterized spectroscopically [3,4], relatively little experimental data on HCCl kinetics are available. In general, HCCl is known to be moderately reactive with unsaturated hydrocarbons and NO, but unreactive with O 2 [5,6]. One previous study of the HCCl + NO reaction has been reported, in which a room temperature rate constant of (1.5 ± 0.5) × 10 −11 cm 3 molecule −1 s −1 was reported [5].…”

“…HCCl is produced by the 193-nm excimer laser photolysis of CHClBr 2 . This precursor is known to produce HCCl from previous kinetic and spectroscopic studies [4][5][6], and cannot produce CH or CCl radicals from a single 193-nm photon. HCCl is probed by laser-induced fluorescence near 603 nm to measure total rate constants [3].…”