Possible atmospheric source of NH2SO3H: the hydrolysis of HNSO2 in the presence of neutral, basic, and acidic catalysts.

ABSTRACT

NH2SO3H can directly participate in H2SO4-(CH3)2NH-based cluster formation, and thereby substantially enhance the cluster formation rate. Herein, the reaction mechanisms and kinetics for the formation of NH2SO3H from the hydrolysis of HNSO2 without and with neutral (H2O, (H2O)2, and (H2O)3), basic (NH3 and CH3NH2), and acidic (HCOOH, H2SO4, H2SO4⋯H2O, and (H2SO4)2) catalysts were studied theoretically at the CCSD(T)-F12/cc-pVDZ-F12//M06-2X/6-311+G(2df,2pd) level. The calculated results showed that neutral, basic, and acidic catalysts decrease the energy barrier by over 18.1 kcal mol-1; meanwhile, the product formation of NH2SO3H was more strongly bonded to neutral, basic, and acidic catalysts than to the reactants HNSO2 and H2O. This reveals that the reported neutral, basic, and acidic catalysts promote the formation of NH2SO3H from the hydrolysis of HNSO2 both kinetically and thermodynamically. Kinetic calculations using the master equation showed that (H2O)2 (100% RH) dominate over the other catalysts within the range of 0-10 km altitudes and 230-320 K with its rate ratio larger by at least 2.98 times, whereas HCOOH (3.2 × 109 molecules cm-3) is the most favorable catalysts at 15 km altitude in the troposphere. Overall, the present results will provide a definitive example that neutral, basic, and acidic catalysts have important influences on atmospheric reactions.