Jimenez, E; Antinolo, M; Ballesteros, B; Canosa, A; Albaladejo, J

[Jimenez, E.; Antinolo, M.; Ballesteros, B.; Albaladejo, J.] Univ Castilla La Mancha, Fac Ciencias & Tecnol Quim, Dept Quim Fis, Avda Camilo Jose Cela S-N, E-13071 Ciudad Real, Spain; [Jimenez, E.; Antinolo, M.; Ballesteros, B.; Albaladejo, J.] Univ Castilla La Mancha, ICCA, Avda Moledores S-N, E-13071 Ciudad Real, Spain; [Canosa, A.] Univ Rennes 1, UMR CNRS UR1 6251, Inst Phys Rennes, Dept Mol Phys, Campus Beaulieu,263 Ave Gen Leclerc, F-35042 Rennes, France

The gas phase chemistry of neutral-neutral reactions of interest in the interstellar medium (ISM) is poorly understood. The rate coefficients (k(OH)) for the majority of the reactions of hydroxyl (OH) radicals with interstellar oxygenated species are unknown at the temperatures of the ISM. In this study, we present the first determination of k(OH) for HC(O)OCH3 between 22.4 +/- 1.4 and 64.2 +/- 1.7 K. The CRESU (French acronym for Cinetique de Reaction en Ecoulement Supersonique Uniforme or Reaction Kinetics in a Uniform Supersonic Flow) technique was used to create a chemical reactor with a uniform temperature and gas density and the pulsed laser photolysis/laser induced fluorescence technique was used to generate OH radicals and to monitor their temporal profile. It was observed that k(OH)(T) increases by one order of magnitude in only similar to 40 K (k(OH)(T = 22 K) = (1.19 +/- 0.36) x 10(-10) cm(3) s(-1) and k(OH)(T = 64 K) = (1.16 +/- 0.12) x 10(-11) cm(3) s(-1)) and similar to 3 orders of magnitude with respect to k(OH)(T = 298 K). This reaction is a very efficient route for the loss of HC(O)OCH3 in the gas phase and may have a great impact on the interpretation of astrophysical models of HC(O)OCH3 abundance in the cold regions of the ISM.