RT Journal Article
T1 Reaction of OH radicals with CH3NH2 in the gas phase: Experimental (11.7-177.5 K) and computed rate coefficients (10-1000 K)
A1 González Fernández, Daniel
A1 Lema Saavedra, Anxo
A1 Espinosa, Sara
A1 Martínez Núñez, Emilio
A1 Fernández Ramos, Antonio
A1 Canosa, André
A1 Ballesteros Ruiz, Bernabé
A1 Jiménez Martínez, Elena
K1 OH radicals
K1 Nitrogen-bearing molecules
K1 Pressure regimes
AB Nitrogen-bearing molecules, like methylamine (CH3NH2), can be the building blocks of amino acids in the interstellar medium (ISM). At the ultralow temperatures of the ISM, it is important to know its gas-phase reactivity towards interstellar radicals and the products formed. In this work, the kinetics of the OH + CH3NH2 reaction was experimentally and theoretically investigated at low- and high-pressure limits (LPL and HPL) between 10 and 1000 K. Moreover, the CH2NH2 and CH3NH yields were computed in the same temperature range for both pressure regimes. A pulsed CRESU (French acronym for Reaction Kinetics in a Uniform Supersonic Flow) apparatus was employed to determine the rate coefficient, k(T), in the 11.7–177.5 K range. A drastic increase of k(T) when the temperature is lowered was observed in agreement with theoretical calculations, evaluated by the competitive canonical unified statistical (CCUS) theory, below 300 K in the LPL regime. The same trend was observed in the HPL regime below 350 K, but the theoretical k(T) values were higher than the experimental ones. Above 200 K, the calculated rate coefficients are improved with respect to previous computational studies and are in excellent agreement with the experimental literature data. In the LPL, the formation of CH3NH becomes largely dominant below ca. 100 K. Conversely, in the HPL regime, CH2NH2 is the only product below 100 K, whereas CH3NH becomes dominant at 298 K with a branching ratio similar to the one found in the LPL regime (≈70%). At T > 300 K, both reaction channels are competitive independently of the pressure regime
PB Royal Society of Chemistry
YR 2022
FD 2022-09-06
LK https://hdl.handle.net/10347/45164
UL https://hdl.handle.net/10347/45164
LA eng
NO González, D., Lema-Saavedra, A, Espinosa, S., Martínez-Núñez, E., Fernández-Ramos, A., Canosa, A., Ballesteros, B.,and Jiménez, E. Phys. Chem. Chem. Phys., 2022,24, 23593-23601
NO This work was supported by the Spanish Ministry of Science and Innovation (MICINN) through the CHEMLIFE project (Ref. PID2020-113936GB-I00), the regional government of Castilla-La Mancha through the CINEMOL project (Ref. SBPLY/19/180501/000052) and by the University of Castilla-La Mancha – UCLM (Ayudas para la financiación de actividades de investigación dirigidas a grupos (Ref: 2021-GRIN-31279). DG and SE also acknowledge UCLM (Plan Propio de Investigación) and CINEMOL project, respectively, for funding their contracts during the performance of this investigation. This work was partially supported by the Consellería de Cultura, Educación e Ordenación Universitaria (Centro singular de investigación de Galicia acreditación 2019-2022, ED431G 2019/03 and Grupo de referencia competitiva ED431C 2021/40) and the European Regional Development Fund (ERDF), and the Ministerio de Ciencia e Innovación through Grant #PID2019-107307RB-I00. ALS thanks Xunta de Galicia for financial support through a postdoctoral grant. AFR, EMN and ALS thank the Centro de Supercomputación de Galicia (CESGA) for the use of their computational facilities
DS Minerva
RD 24 abr 2026