A great variety of complex organic molecules (COMs) have been detected by astronomical observations in the interstellar medium (ISM) in the last 50 years. Formaldehyde (H2CO) and ethanol (CH3CH2OH) are two of these COMs of importance in prebiotic chemistry in space. In order to model their observed abundances, chemical models need the rate coefficients (k) of the processes in which the COM is involved at the temperatures of ISM (∼10-100 K). For many gas-phase reactions with OH radicals, ubiquitous in the ISM, k is unknown at these ultra-low temperatures, mainly because of the experimental difficulty of reproducing those extreme temperature conditions without condensation of the species. The pulsed and continuous CRESU technique is a powerful tool that allows measuring rate coefficients of IS reactions [1,2]. In our group, some OH-molecule reactions have been recently investigated for methyl formate [3] and methanol [4] between 22 and 61 K using this technique coupled to pulsed laser photolysis and laser induced fluorescence. Currently, this temperature range has been extended up to 107 K and the OH+H2CO reaction has been investigated for the first time between 22 and 107 K (submitted to PNAS) as well as the OH + CH3CH2OH for which, up to now, there is only a previous study at ISM temperatures between 54 and 148 K [5]. In both cases, we found a significant increase of the rate coefficient below 200 K making these processes potentially interesting for the chemistry in the ISM.

References
[1] A. Potapov, A. Canosa, E. Jiménez, and B.R. Rowe. Angew. Chem. Int. Ed., 56[30], 8618-

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[2] E. Jiménez, B. Ballesteros, A. Canosa, A. et al., J. Rev. Sci. Instr. 86 (2015) 045108/1-17.

[3] E. Jiménez, M. Antiñolo, B. Ballesteros, A. Canosa, and J. Albaladejo. Phys. Chem. Chem. Phys., 18[3], 2183-2191 (2016).
[4] M. Antiñolo, M. Agúndez, E. Jiménez, B. Ballesteros, A. Canosa, G. El Dib, J. Albaladejo, and J. Cernicharo. Astrophys. J., 823[1], 25 (2016).

[5] R. L. Caravan, R. J. Shannon, T. Lewis, M. A. Blitz, and D. E. Heard, J. Phys. Chem. A. 119 (2015)7130–7137.