Kinetics of nitrogen tetroxide absorption in water

Abstract

AbstractThe rate of absorption of nitrogen peroxide into water at 25° and 40°C. has been found to be a linear function of the concentration of nitrogen tetroxide in the gas phase and directly proportional to the interfacial partial pressure of the same species.The rate of absorption is independent of gas velocity over a range of ReG from 170 to 350. The results plotted as absorption rate divided by interfacial partial pressure of nitrogen tetroxide show no effect of liquid rate or contact time between gas and liquid over a tenfold range of contact time from 0.03 to 0.3 sec. This indicates that the rate‐controlling step during nitrogen dioxide absorption into water is the rate of hydrolysis of nitrogen tetroxide.The absorption rate decreases with increasing temperature from 25° to 40°C., owing to the shift of the equilibrium in the gas phase away from the reacting species nitrogen tetroxide toward nitrogen dioxide and owing to the the decreased solubility of nitrogen tetroxide in water. The effect of these factors on absorption more than offsets the effect of the increase in reaction rate and higher diffusivity on absorption at 40°C.The reaction rate constant for the hydrolysis of nitrogen tetroxide has been determined and the solubility of dissolved but unreacted nitrogen tetroxide in equilibrium with gaseous nitrogen tetroxide has been found.