Infrared spectroscopic and thermographic evidence for the interaction of ethylene and 1,3-butadiene with N2O4 at cryogenic temperatures

Abstract

The possibility of the reaction of ethylene at cryogenic temperatures with dinitrogen tetroxide (N2O4), at least at –40 °C, has been demonstrated. An infrared (IR) spectroscopic analysis of the condensed reaction products was carried out, which showed the presence of substances containing organic nitro compounds and organic nitrates. The latter particularly means the possibility of the formation of explosive substances, as in the known explosive cryogenic reaction of N2O4 with butadiene. The fundamental possibility of such a reaction is of importance for the organization of cryogenic production of gases from raw materials containing ethylene and nitrogen oxide impurities. The sensitivity of the experimental setup was demonstrated by using the example of the known reaction of N2O4 with butadiene. The temperature and time characteristics of the latter reaction have been found. To determine the temperature range of possible reactions of ethylene with N2O4, thermograms of the process of heating the reactive mixture at a constant rate were analyzed. To ensure the sensitivity of the qualitative analysis of thermograms of the reaction of ethylene with N2O4 in the linear heating mode, a quasi-differential method was proposed that uses the temperature of the cryo-thermostat coolant, which varies linearly with time, as the reference temperature. Some recently published theoretical results concerning the mechanisms of N2O4 isomerization are discussed which may be useful for further studies in establishing the mechanisms and predicting the ratios of the products and their yields for the reaction of N2O4 with olefins under particular experimental conditions.