Experimental Gas-Phase Removal of OH Radicals in the Presence of NHC(O)H over the 11.7-353 K Range: Implications in the Chemistry of the Interstellar Medium and the Earth's Atmosphere.

Formamide (NHC(O)H) has been observed both in the interstellar medium (ISM), being identified as a potential precursor of prebiotic molecules in space, and in the Earth's atmosphere. In these environments where temperature is very distinct, hydroxyl (OH) radicals may play an important role in the degradation of NHC(O)H. Thus, in this work, we report for the first time the experimental study of the temperature dependence of the gas-phase removal of OH in the presence of NHC(O)H over the 11.

Atmospheric chemistry of CFCHFCFOCH (HFE-356mec3) and CHFCHFOCF (HFE-236ea1) initiated by OH and Cl and their contribution to global warming.

The kinetic study of the gas-phase reactions of hydroxyl (OH) radicals and chlorine (Cl) atoms with CFCHFCFOCH (HFE-356mec3) and CHFCHFOCF (HFE-236ea1) was performed by the pulsed laser photolysis/laser-induced fluorescence technique and a relative method by using Fourier Transform infrared (FTIR) spectroscopy as detection technique. The temperature dependences of the OH-rate coefficients (k(T) in cms) between 263 and 353 K are well described by the following expressions: 9.93 × 10exp{-(988 ± 35)/T}for HFE-356mec3 and 4.

Kinetic and Products Study of the Atmospheric Degradation of -2-Hexenal with Cl Atoms.

The gas-phase reaction between -2-hexenal (T2H) and chlorine atoms (Cl) was studied using three complementary experimental setups at atmospheric pressure and room temperature. In this work, we studied the rate constant for the titled oxidation reaction as well as the formation of the gas-phase products and secondary organic aerosols (SOAs). The rate constant of the T2H + Cl reaction was determined using the relative method in a simulation chamber using proton-transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS) to monitor the loss of T2H and the reference compound.

Kinetics of CFCHOCH (HFE-263fb2), CHFCFCHOCH (HFE-374pcf), and CFCFCHOCH (HFE-365mcf3) with OH radicals, IR absorption cross sections, and global warming potentials.

Hydrofluoroethers (HFEs), such as CFCHOCH (HFE-263fb2), CHFCFCHOCH (HFE-374pcf), and CFCFCHOCH (HFE-365mcf3), have been proposed in the last few decades as the third-generation replacements for perfluorocarbons (PFCs) and hydrofluorocarbons (HFCs) because of their zero stratospheric ozone depletion potentials and relatively low global warming potentials (GWPs). These GWPs depend on the radiative efficiency (RE) and the atmospheric lifetime () of HFEs due to the reaction with hydroxyl (OH) radicals. The temperature and pressure dependencies of the OH-rate coefficient (()) for HFE-263fb2, HFE-374pcf, and HFE-365mcf3 are not known.

The impact of water vapor on the OH reactivity toward CHCHO at ultra-low temperatures (21.7-135.0 K): Experiments and theory.

The role of water vapor (HO) and its hydrogen-bonded complexes in the gas-phase reactivity of organic compounds with hydroxyl (OH) radicals has been the subject of many recent studies. Contradictory effects have been reported at temperatures between 200 and 400 K. For the OH + acetaldehyde reaction, a slight catalytic effect of HO was previously reported at temperatures between 60 and 118 K.