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

The reaction of fulminic acid, HCNO, with NH2 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 cm3 molecule−1 s−1 at room temperature, to > 1 × 10−10 cm3 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, H2NCO + NO is the dominant product, with H2NCN + OH and HCN + NHOH contributing weakly. This work presents rate coefficients and product distributions for the temperature range 300-3000 K, and pressure range of 10−3-103 bar; a brute-force error analysis examines the expected uncertainty interval for these predictions.