Theoretical determination of the properties of methanesulfinic and methanesulfonic acids

Abstract

The structural, spectroscopic and thermochemical properties of two sulfur species of atmospheric interest, methanesulfinic (CH3S(O)OH, MSIA) and methanesulfonic (CH3S(O)2OH, MSA) acids, were determined at the CCSD(T)/CBS (coupled-cluster with single and double and perturbative triple excitations/complete basis set) level of theory. Two stable conformers were found to the methanesulfinic acid, and the determined average value for the enthalpy of formation (AHf) was-337.2 kJ mol -1. For methanesulfonic acid, the determined enthalpy of formation was 566.2 kJ mol-1. By carefully choosing of the chemical reactions and considering the existence of two MSIA conformers, this investigation reports the most accurate AHf values available to date for these species. © 2011 Sociedade Brasileira de Química.