Theoretical Mechanistic Study on the Radical−Molecule Reaction of CH₂OH with NO₂

Abstract

The complex singlet potential energy surface for the reaction of CH2OH with NO2, including 14 minimum isomers and 28 transition states, is explored theoretically at the B3LYP/6-311G(d,p) and Gaussian-3 (single-point) levels. The initial association between CH2OH and NO2 is found to be the carbon-to-nitrogen approach forming an adduct HOCH2NO2 (1) with no barrier, followed by C-N bond rupture along with a concerted H-shift leading to product P1 (CH2O + trans-HONO), which is the most abundant. Much less competitively, 1 can undergo the C-O bond formation along with C-N bond rupture to isomer HOCH2ONO (2), which will take subsequent cis-trans conversion and dissociation to P2 (HOCHO + HNO), P3 (CH2O + HNO2), and P4 (CH2O + cis-HONO) with comparable yields. The obtained species CH2O in primary product P1 is in good agreement with kinetic detection in experiment. Because the intermediate and transition state involved in the most favorable pathway all lie blow the reactants, the CH2OH + NO2 reaction is expected to be rapid, as is confirmed by experiment. These calculations indicate that the title reaction proceeds mostly through singlet pathways; less go through triplet pathways. In addition, a mechanistic comparison is made with the reactions CH3 + NO2 and CH3O + NO2. The present results can lead us to deeply understand the mechanism of the title reaction and may be helpful for understanding NO2-combustion chemistry.

Global exploration of isomers and isomerization channels on the quantum chemical potential energy surface of H3CNO3

“…Computational studies on the isomers and isomerization channels of H 3 CNO 3 were found to be limited. For the reaction of CH 2 OH with NO 2 , theoretical exploration of the singlet PES was made at B3LYP/6‐311G(d,p) and G3 single point levels, and 14 EQ and 28 TS were reported . This is an outstanding study of H 3 CNO 3 , but it includes only limited parts of isomerization channels around nitromethanol 12 (HOCH 2 NO 2 ) and local species of 7 , 8 , 10 , 15 , and 18 .…”

“…This article describes a study on the exploration of isomers, isomerization reactions, as well as their reaction routes for H 3 CNO 3 using SHS‐ADDF. Studies on H 3 CNO 3 were reported recently in relation to combustion and atmospheric chemistry . The reaction channels for some isomers of H 3 CNO 3 including nitromethanol (HOCH 2 NO 2 ) and nitrosooxymethnol (HOCH 2 ONO) were elucidated using hybrid density‐functional‐theory (DFT) B3LYP method in connection with radical‐molecule reaction of CH 2 OH with NO 2 .…”

“…Studies on H 3 CNO 3 were reported recently in relation to combustion and atmospheric chemistry . The reaction channels for some isomers of H 3 CNO 3 including nitromethanol (HOCH 2 NO 2 ) and nitrosooxymethnol (HOCH 2 ONO) were elucidated using hybrid density‐functional‐theory (DFT) B3LYP method in connection with radical‐molecule reaction of CH 2 OH with NO 2 . The reaction channels involving methyl nitrate (H 3 CONO 2 ) and methyl peroxynitrite (H 3 COONO) related to atmospheric systems were studied in different levels of calculations .…”

Theoretical Study on the Dynamics and Kinetics of the Reaction of CH2OH with OH

“…Hydroxyalkyl radicals can advance various reactions with HO x . In fact, hydroxyalkyl radicals are a subclass of oxygenated carbon-centered free radicals that are produced as intermediates in various reaction sequences . The carbon-centered oxy radicals are thermodynamically more stable than the isomeric oxygen-centered alkoxy radicals .…”

Product Channels in the Reaction of the Hydroxymethyl Radical with Nitric Oxide

“…The hydroxymethyl (CH 2 OH) radical is of interest to combustion chemists due to its importance in the combustion and atmospheric chemistry, as well as its capability to react with NO X species. Reactions of the CH 2 OH radical with NO 2 , , O 2 , hydrogen halides, − H 2 O, H 2 O 2 , several saturated and unsaturated hydrocarbons, − OH, and HO 2 , , have been studied by experiment or ab initio calculation. In the one previous experimental study of the kinetics of the title reaction, Pagsberg et al suggested two possible product channels: …”