Theoretical Study on the Mechanism of the NCO + HCNO Reaction

Abstract

The complex doublet potential surface of the NCO + HCNO reaction has been investigated at the QCISD(T)/6-311g(d,p)//UB3LYP/6-31G(d,p) level. We have found 29 isomers on the potential surface, which are connected by 38 transition states. The single-point energy calculations are performed at the high-level QCISD(T)/6-311G(d,p) for more accurate energy values. In various possible initial association ways, the end-N attack leading to HC2N2O2 a1 and a2 is the most favorable association way through a barrierless process. Through the thermodynamic and kinetic analyses, the product NO + CO + HCN should be the major product in both the low- and high-temperature conditions for its low-energy determination transition state. Our calculation is consistent with the available data in low-temperature condition and expected to be confirmed in the high-temperature condition.

Theoretical studies and topological analysis of the electron density of clusters of O3 with HNCO and HCNO

“…Several experimental and computational studies on the kinetics of HCNO have been reported [16][17][18][19][20][21][22][23]. Despite the potential importance of O 3 , HNCO and HCNO we could not find neither experimental nor theoretical report on O 3 -HNCO or O 3 -HCNO interactions.…”

Prediction of the product channels in the reaction of the methyl radical with fulminic acid

“…The structure and properties of HCNO such as vibrational frequencies, ionization energy, heat of formation, and so on have long been reported based on both experimental and theoretical methods. [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] The geometry of the HCNO has been determined by Beck et al [11][12][13] from the IR spectrum when they isolated HCNO for the first time in the pure state. Their results show that this acid has three bonds including H─C, C─N, and N─O in the molecule supporting the formyl nitrile oxide structure, HCNO, rather than the oxime structure, CNOH, 28 as proposed before.…”

“…A number of reactions of HCNO with small radicals such as OH, NH (singlet and triplet), CN, and OCN were investigated either experimentally or theoretically. 3,[14][15][16][17][29][30][31][32][33][34] In general, theoretical results showed that the initial association to the C-atom in HCNO is a major entrance channel leading to the dominant products, and that this process can occur via either a barrierless process or a well-defined transition structure. For example, HCNO reacts with O( 3 P), CN, NCO in barrierless processes to form HC(X)NO, in which X is the reactant species.…”

“…For example, HCNO reacts with O( 3 P), CN, NCO in barrierless processes to form HC(X)NO, in which X is the reactant species. 16,17,32,34 Conversely, for the reaction of HCNO with 3 NH, Li et al 15 showed that although the most feasible pathway is still nitrogen attack on the carbon center leading to HC(NH)NO, the reactants have to surmount a well-defined transition state lying at ∼3 kcal/mol above the reactants.…”

A density functional investigation of the reaction mechanism of H2O + HCNO

“…HCNO is formed in combustion primarily by the CH 2 + NO [2][3][4][5] and HCCO + NO [6][7][8][9][10][11] reactions, and can be synthesized by vacuum pyrolysis of 3-phenyl-4-oximinoisoxazol-5(4H)-one [12][13][14]. Several experimental [15][16][17][18] and computational studies [19][20][21] on the kinetics of HCNO have been reported. There are many researchers have studied in this area, for example, Miller et al reported a theoretical study on the kinetics of the O+HCNO reaction [19]; Hershberger and coworkers reported an experimental study of the kinetics of O+ HCNO reaction, using diode laser infrared adsorption spectroscopy to detect the product species.…”