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

Abstract

A theoretical investigation of the H 2 O + HCNO reaction, which is carried out by means of CCSD(T)/6-311G(d,p)//B3LYP/6-311G(d,p)+ZPVE computational method to determine a set of reasonable pathways, there are seven product pathways, P i with i = 1, 2, . . . , 7 are involved. It is shown that P 1 (H 2 O + NCOH), P 2 (CO + NH 2 + OH), P 4 (HCN + HO 2 + H), and P 6 (CO + NH 2 OH) are the major product channels; and P 7 (HOC + H 2 + NO) is the minor product channels, whereas the other channels for P 3 (HNO + HCOH) and P 5 (HNO + H 2 CO) are very minor, the minor product channels.

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

“…32 These results are similar to reactions of HCNO with other radicals such as OH, 3 NH, and so on. 3,14,[32][33][34] Of the four entrance transition structures, the addition of CH 3 to the HCNO carbon atom is expected to be the dominant channel, owing to its low entrance barrier as compared with those of the other channels. H-abstraction begins to contribute only at high temperatures only.…”

“…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.…”

Theoretical computation of low‐lying electronic states of HCNS: A CASPT2 study

“…They are generated in situ for the synthesis of various types of heterocycles and many biologically active compounds 2, 4. Although some molecules with similar structure as HCNS, such as PhCNS, CH 3 CNS, and fulminic acid (HC≡N + O − ), have been observed,3, 7–10 the chemistry of HCNS (HC≡N + S − ) still remains to be elucidated. Because of the instability of HCNS, it has been only indirectly observed by means of neutralization deionization mass spectrometry 11, 12.…”