Chemical Reactivity of [(NO)_n(ROH)_m]⁺ Cluster Ions

Abstract

Mixed clusters of nitric oxide and various alcohols (ethanol, n-propanol, 2-propanol, n-butanol, 2-butanol, and tert-butyl alcohol) were generated via a continuous molecular beam expansion and analyzed using an electron impact tandem triple quadrupole mass spectrometer. The unique chemistry of the [(NO) n (ROH) m ]+ cluster ions was investigated employing collision induced dissociation (CID). Formation of product cluster ions containing alkyl nitrites [(NO) n (RONO)]+ and the subsequent loss of neutral HNO (when n = 1) are the most prominent features of this chemistry.

Nitrosamide, (H2NNO), formation within [(NO)m(NH3)n]+ clusters: Theory and experiment

“…However, it appears to be unlikely that such protonated cluster ions are formed within clusters because we saw no evidence supporting the formation of the protonated form in our previous study of NO/NH 3 [37] and NO/ROH [32][33][34]41] systems, even though protonated cluster ions such as (NH 3 ) n H + and (CH 3 OH) n H + are mainly observed when NH 3 and CH 3 OH, respectively, are expanded.…”

“…observed, even though the major mixed cluster series in all mass spectra is found to be [(NO)(NH 3 ) n ] + . We observe the generation of H 2 NNO only in mixed cluster ions possessing two or more NO molecules, which is similar to NO/ROH system [32][33][34]41].…”

“…These results imply fundamental differences between the NO/ROH and NO/NH 3 systems. This effort can lend some insight into the chemical reactivity of NO cluster ions with NH 3 to generate the H 2 NNO species within clusters (similar to the generation of RONO in the NO/ROH system [32][33][34]41]). We had observed in our previous studies of NO/ROH clusters [32][33][34]41], that the formation of the RONO species seems to require at least two or more NO molecules within the initial heterocluster ion (i.e., [(NO) m>1 (CH 3 OH) n ] + ).…”

“…Previous experiments have reported observation [32][33][34] of chemical reactivity of NO cluster ions toward molecules containing a hydroxyl group (i.e., CH 3 OH, C 2 H 5 OH, C 3 H 7 OH and C 4 H 9 OH). This suggests that alcohols might also be employed as an additive to improve the efficiency of the DeNO x processes [7,35].…”

“…This competitive switching pattern in the position of the hydrogen atom loss against the ethanol concentration is thought to be controlled by the degree of the hydrogen-bonding network within cluster ions. In cases where mixed clusters of NO/ROH (ROH = C 2 H 5 OH, C 3 H 7 OH and C 4 H 9 OH) are used [34], the formation of the product cluster ions having RONO species is predominantly observed as a major series. Based on this past work, it is interesting to speculate on whether the chemical reaction within NO/NH 3 clusters occurs in a manner similar to that within NO/ROH clusters.…”