Experimental and theoretical study of the reaction system of 2NO2↔N2O4 and some fluorinated derivatives of butanols in the gas phase

• Published in: Journal of molecular structure 2013-11, Vol.1052, p.1-7
• Main Authors: Wójcik-Pastuszka, Dorota, Kołodziejczyk, Wojciech, Berkowski, Ryszard
• Format: Article
• Language: English
• Subjects: activation energy; DFT; Dinitrogen tetroxide; energy; Fluorinated butanols; gases; Nitrogen dioxide; temperature; wavelengths
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2013.08.036

•Products spectra of reactions of 2NO2↔N2O4 with some fluorobutanols were registered.•The rate constants of the reactions in the temperature range of 298–358K were obtained.•The activation energies for the reactions were calculated.•The mechanism of the reaction involving N2O4 was proposed.•The DFT calculations of UV–Vis spectra and reactions was studied. The reversible reaction of NO2/N2O4 with CF3CH(F)CF2CH2OH and CF3CF2CF2CH2OH in the temperature range of 298–358K by UV–Vis spectrophotometry in the gas phase has been studied. The final products of the reactions: CF3CH(F)CF2CH2ONO and CF3CF2CF2CH2ONO were identified by their UV spectra in the wavelength range between 340–400nm. The rate constant for the forward k3 as well as for the reverse reaction k4 were derived and the values at 298K are 10−19k3/cm3molecule−1s−1 2.6±0.6; 1.0±0.25 and 10−19k4/cm3molecule−1s−1 20.2±4.0; 3.4±0.7 for the reaction of NO2/N2O4 with CF3CH(F)CF2CH2OH and CF3CF2CF2CH2OH, respectively. From the temperature dependence of the rate constants, the activation energy for the forward E3 and for the reverse E4 reaction were obtained. It was proposed that the dimer N2O4 is the reactive species. The all possible low energy conformers of measured compounds have been calculated using DFT (PBE, B3LYP) with 6-31G(d,p). Population of each conformer has been calculated using Boltzman’s distribution. UV–Vis spectra have been calculated and compared to the experiment.