Spectrokinetic Study of the Reaction System of 2NO2<->N2O4 with Butanols Between 320-358 K in the Gas Phase

摘要

Spectrokinetic studies of the gas-phase equilibrium between nitrogen tetroxide and butanols in the reaction system 2NO2<->N2O4 (1,2), N2O4+ROH<->RONO+HNO3 (3,4) have been undertaken in the temperature range 298-358 K. The products - RONO (n-butyl-ONO, sec-butyl-ONO, iso-butyl-ONO and tert-butyl-ONO) - were identified by their UV spectra and the values of the maxima UV absorption cross sections were determined in the range 320-420 nm at 298 K. The temperature dependences of both the forward and reverse rate constants, k3 and k4, were obtained. The extrapolated values of the forward rate constants are 10~(-18) k_3~(av)/cm~3 molec~(-1) s~(-1) 3.9±1.0; 1.7±0.3; 4.2±0.8; 5.7±1.1 and the reverse rate constants are 10~(-20) k_4~(av)/cm~3 molec~(-1) s~(-1) 0.3±0.1; 2.3±0.6; 0.4±0.1; 2.3±0.6 at 298 K for the reaction of NO2/N2O4 with n-butanol, sec-butanol, iso-butanol and tert-butanol, respectively. The activation energy for the forward E3 and for the reverse E4 reaction were derived.