Ion–molecule reactions in formic-d acid and methyl formate

Abstract

The following ion-molecules reactions have been found to occur in DCOOH for ions produced by bombardment with electrons of 10-15 eV energy (all rate constants in cm3 molecule-l units).[a] DC02H+ + DC0,H + DCO,HD+ + C0,H k = 1.0 x lo-,In methyl formate the following reactions have been identified and rate constants measured for ions formed by bombardment with electrons of 10-15 eV energy.[ f ] HC02CH3+ + HC02CH3 -. HC02CH3HC + ? k = 1.57 X lo-'Experiments using DCOzCH3 show that reaction [ f ] involves transfer of the methyl hydrogen at a rate 1.5 times that of the formyl hydrogen while reaction [ g ] involves transfer from only the methyl position of CH30H+. The rate constants for all reactions are considerably higher than predicted on the basis of ion -induced dipole interactions only but are in good agreement with values calculated by including ion-dipole interactions.

Collision‐induced dissociation processes of protonated benzoic acid and related compounds: competitive generation of protonated carbon dioxide or protonated benzene

“…Although the protonation of CO 2 can occur at two different sites, an attachment of the proton to one of the oxygen atoms generates the more favorable that the hydroxycarbonyl cation (H ‐ O + ═ C ≡ O) . In fact, calculations have shown that the isomeric formyloxy cation (H–CO 2 + ) is about 90 kcal/mol less stable than the hydroxycarbonyl form . Our search by DFT calculations for energy‐minimized structures confirmed that the species which best represents the protonated CO 2 is that with the proton attached to one of the oxygen atoms of CO 2 (Fig.…”

“…We envisaged that the m/z 45 peak represents protonated carbon dioxide. Although the protonation of CO 2 can occur at two different sites, an attachment of the proton to one of the oxygen atoms generates the more favorable that the hydroxycarbonyl cation (H ‐ O + ═ C ≡ O) . In fact, calculations have shown that the isomeric formyloxy cation (H–CO 2 + ) is about 90 kcal/mol less stable than the hydroxycarbonyl form .…”

“…This interesting ion is thought to play an important role in the formation of interstellar molecules . Although the existence of it has been noted in very early studies on electron–ionization (EI), collisional activation (CA), fast‐atom‐bombardment (FAB) and chemical ionization mass spectrometry, its significance as a diagnostic marker for structural investigations has not been duly recognized. Moreover, the intricate details of its formation have not been mechanistically rationalized .…”

Dissociative Electron-Ion Recombination of the Interstellar Species Protonated Glycolaldehyde, Acetic Acid, and Methyl Formate

“…Fortunately, protonated methyl formate can be produced through other reactions as outlined in the literature. This procedure involves a charge transfer to methyl formate from Ar + and Kr + , followed by a proton transfer with neutral methyl formate, i.e., HCO 2 CH 3 + + HCO 2 CH 3 → HCO 2 CH 3 normalH + + CO 2 CH 3 goodbreak0em1em⁣ italick = 1.57 × 10 − 9 .25em cm 3 .25em molecule − 1 …”

“…Fortunately, protonated methyl formate can be produced through other reactions as outlined in the literature. This procedure involves a charge transfer to methyl formate from Ar + and Kr + , followed by a proton transfer with neutral methyl formate, 33 i.e.,…”