AB-INITIO STUDY OF PROTONATED NITROSAMIDE - A POSSIBLE INTERMEDIATE IN THE DENO-X-PROCESS

Ab initio calculations on protonated nitrosamide, a possible intermedi ate in the deNOx process, have been performed. A mechanism involving t he formation of an intermediate NH3NO+ was proposed by Egsgaard, Carls en and Madsen and tested by performing flame experiments with mass spe ctrometry. In the present work, the absence of NH3NO+ in the flame has been supported on the basis of its structure. This cation is observed to be a loosely bound adduct of NH3 and NO+ at and beyond the HF leve l of theory. On the other hand, NH2NOH+ is found to be a covalently bo nded compound at all theoretical levels. Topographical analysis of ele ctron density and electrostatic potential has been utilized to gain in sight into bonding properties and to predict the possible sites of pro tonation. The vibrational spectra of both protonated nitrosamide catio ns are reported. The feasibility of proton transfer reactions of NH3NO + with ammonia and water are investigated using heats of reactions. Th ese values indicate that such a reaction is possible with NH3 but unfa vorable with H2O.