Mechanism and kinetics for the reaction of fulminic acid, HCNO, with an amino radical, NH2

Abstract

The reaction of fulminic acid, HCNO, with NH 2 radicals was studied using quantum chemical and theoretical kinetic methodologies. B3LYP/6-311++G(3df,2p) calculations combined with CCSD(T) energy calculations at the basis set limit reveal a complex potential energy surface, where only two entrance channels contribute significantly to the product formation. Transition state theory and RRKM master equation calculations find a rate coefficient ranging from 7.2  10-12 cm 3 molecule-1 s-1 at room temperature, to > 1 10-10 cm 3 molecule-1 s-1 at 3000 K. Despite a reduced efficiency in product formation due to fast redissociation of the adducts to the reactants at high temperatures, the title reaction can thus be an efficient sink for HCNO at combustion temperatures in nitrogen-rich environments. At 1 bar and below, H 2 NCO + NO is the dominant product, with H 2 NCN + OH and HCN + NHOH contributing weakly. This work presents rate coefficients and product distributions for the temperature range 300-3000K, and pressure range of 10-3 to 10 3 bar; a brute-force error analysis examines the expected uncertainty interval for these predictions.

Gas-phase molecular formation mechanisms of cyanamide (NH2CN) and its tautomer carbodiimide (HNCNH) under Sgr B2(N) astrophysical conditions

“…In 1986, Cummins et al confirmed its presence in Sgr B2 but this time at the millimeter spectrum bands. Nummelin et al et al, in 1998 and2000, further refined the detection of NH 2 CN in Sgr B2, specifying the emitting regions inside the molecular cloud (M for "Middle" and N for "North"), which was confirmed in 2014 by Belloche et al. In 2003, the presence of NH 2 CN in the central area of the Orion molecular complex (Orion KL) was reported by White et al, expanding the known presence of this molecule in our galaxy.…”

“…However, the only way to form this product is through preceding protonation, which is not a robustly useful result. Fulminic acid and the amino radical reaction (•NH 2 + HCNO → NH 2 CN + •OH) were analyzed by Nguyen, Nguyen, & Vereecken (2018) for a temperature range of 700 to 2000 K at 1 atm. This reaction under the produced temperature and pressure (P&T) profiles is normally applicable in combustion studies.…”