Kinetics of the CN + CS₂ and CN + SO₂ Reactions

Abstract

Diode infrared laser absorption spectroscopy was used to measure the rate constant (k(1)) of the CN + CS(2) reaction for the first time. k(1) was determined to be substantially pressure dependent with a value k(1) = (7.1 ± 0.2 to 41.9 ± 2.9) × 10(-12) cm(3) molecule(-1) s(-1) over 2-40 Torr at 298 K. The potential energy surface (PES) of the reaction was calculated using an ab initio method at B3LYP/6-311++G(d, p)//CCSD(T)/6-311++G(d, p) level of theory. Both experimental and computational results suggest that collision stabilization of the adduct NCSCS may dominate the reaction. The rate constant of the CN + SO(2) reaction was measured to be very slow with an upper limit of k(2) ≤ 3.1 × 10(-14) cm(3) molecule(-1) s(-1), in disagreement with an earlier reported measurement. The PES of this reaction reveals an entrance barrier against formation of the low energy adduct NCOSO, in agreement with the experimental result.

Combined Spectroscopic and Theoretical Approach to Sulfur-Poisoning on Cu-Supported Ti–Zr Mixed Oxide Catalyst in the Selective Catalytic Reduction of NOx

“…Due to the low activation energy of 3.0 kcal/mol, this reaction could take place easily, even in a low temperature region, which well explains the absence of −CN species and the enhancement of the −NCO species generation in the whole temperature range of 150–350 °C, as presented in Figure b. The calculation results about the reaction of −CN + SO 2 → −NCO + SO was similar to that reported by Hershberger et al…”

Kinetics of the O + ICN Reaction

“…This would lead to an observed decay rate for [CN] vs time that is slower than would be expected from the CN + O 2 reaction alone, resulting in an erroneously small value of the CN + O 2 rate constant. A similar issue was raised in our recent study of CN + SO 2 kinetics, in which we found essentially no reaction with k ≤ 3.1 × 10 −14 cm 3 molecule −1 s −1 , 25 in contrast to an earlier literature value of 4.4 × 10 −12 cm 3 molecule −1 s −1 . 26 Is it possible that O atom formation (possibly via SO 2 multiphoton dissociation or reaction of CN with trace O 2 ) followed by the O + ICN reaction resulted in regeneration of CN radicals, and therefore led to an erroneously small value for the CN + SO 2 rate constant?…”

Reaction kinetics of the CN radical with primary alcohols

“…CN reactions with a variety of molecules have been previously studied, including both saturated and unsaturated hydrocarbons [1][2][3][4][5][6][7], O 2 [1,[8][9][10][11][12][13][14][15][16], NO [15,17], and NO 2 [16,17]. Past work in our laboratory has included study of CN reactions with O 2 [18,19], NO 2 [20], OCS [21], CS 2 [22], SO 2 [22], and HCNO [23,24]. To date, however, there is no literature on the kinetics of CN reactions with alcohols.…”