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

Abstract

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.