Oxidation of cyanogen. II. The mechanism of the oxidation

Abstract

A detailed investigation of the mechanism of cyanogen oxidation is presented. Recent induction time measurements of ignition in cyanogen-xygen-argon mixtures behind reflected shocks are computer modeled to obtain an agreement between the experimental and calculated values. A 15-step reaction scheme is suggested to reproduce the parameters E and pi in the experimental parametric relation: T = lO"exp(E/RT)IIC?. An explanation is offered to the very strong dependence of the induction time on the cyanogen concentration and the very weak dependence on the oxygen concentration. The sensitivity spectrum shows that the induction time is highly dependent on the 0 + C2N2 -NCO + CN and NCO + M -N + CO + M reactions (shortened) and the 0 + NCO -CO + NO and N + NCO -N2 + CO reactions (increased).

Characterization of Chemical Sources of N2(A3 sigma Summation of sub + u)

“…The modeling studies (see pg. 18), using the kinetic scheme shown in Table 1, confirmed that the major loss of NCO would be by reaction with 0 under a variety of conditions (although this depends on an estimated rate coefficient of 1.7 x 10-11 cm 3 molecule-' s " 1 for Reaction (20)]. It can be seen that Reaction (20) produces NO, so that, if Reactions (24) and (20) have similar rate coefficients, the observed single-exponential decay may be explained.…”

“…18), using the kinetic scheme shown in Table 1, confirmed that the major loss of NCO would be by reaction with 0 under a variety of conditions (although this depends on an estimated rate coefficient of 1.7 x 10-11 cm 3 molecule-' s " 1 for Reaction (20)]. It can be seen that Reaction (20) produces NO, so that, if Reactions (24) and (20) have similar rate coefficients, the observed single-exponential decay may be explained. It was clear, however, that this study could not give a good value of the rate coefficient for Reaction (20) or assess the role of other NCO removal processes (like Reaction (15)], so further attempts to characterize NCO chemistry by LIF measurements in this system were abandoned.…”

“…It can be seen that Reaction (20) produces NO, so that, if Reactions (24) and (20) have similar rate coefficients, the observed single-exponential decay may be explained. It was clear, however, that this study could not give a good value of the rate coefficient for Reaction (20) or assess the role of other NCO removal processes (like Reaction (15)], so further attempts to characterize NCO chemistry by LIF measurements in this system were abandoned. Figure 2 shows the emission spectrum produced by 158-nm radiation of a Of the three reactions sufficiently exothermic to produce N 2 (A) [Reactions (15a), (21), and (22)), Reaction (22) can be dismissed in the cyanogenoxygen system because it is slow and because the NO 7-band yield is enhanced by 02 addition to a cyanogen-NO mixture rather than suppressed, as it would be if Reaction (21) were the N 2 (A) source.…”

Properties of plasma flames sustained by microwaves and burning hydrocarbon fuels

“…44 The where NCO dissociates to nitrogen and carbon monoxide in 1700 K, 45 according to NCO → N + CO ͑k = 1.72 ϫ 10 12 cm 3 /mol s͒. 44 The where NCO dissociates to nitrogen and carbon monoxide in 1700 K, 45 according to NCO → N + CO ͑k = 1.72 ϫ 10 12 cm 3 /mol s͒.…”

A New Data-Driven Sparse-Learning Approach to Study Chemical Reaction Networks

“…Of particular interest is the influence of kinetics parameters on combustion characteristics, such as ignition delay or heat release trends. The brute force approach to such sensitivity analysis is to evaluate the impact of each reaction on the combustion feature of interest by perturbing the rates one by one [15][16][17]. This brute force scheme is straightforward to implement but becomes overly computationally expensive for large mechanisms as a full simulation run is required for every change in the kinetic parameters.…”