Kinetics of nitrogen tetroxide absorption in water

Abstract

The 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 Recl 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 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.Despite the large quantities of nitric acid made by the absorption of nitrogen oxides into water, the kinetics of the reactions involved are not yet fully explained. These reactions are commonly written asThe reaction shown in Equation (3) is the least-understood step of the three.Future efforts to improve the already high efficiency of absorption towers where reaction (3) is carried out will be based on a better understanding of the kinetics of this reaction. To add to the knowledge of this reaction, a study has been made of the kinetics of the absorption and reaction of nitrogen peroxide* with water. Others (4, 6 , LO) who have studied this same problem have shown that nitrogen tetroxide is the reacting species in Equation (3) and that the *Nitrogen peroxide refers to the equilibrium M. M. Wendel is with E.

The kinetics of the absorption of phosgene into water and aqueous solutions

“…This may be estimated from the solubility of phosgene in aqueous sodium nitrate solutions by a method similar to that used by Markham and Kobe (12) which has been described in detail by Wendel (26). Briefly it used the fact that the salting out of gases by strong electrolytes in water has been found to depend additively on the effects of the ions present.…”

Predicting vertical film flow characteristics in the entrance region

“…The laminar flow boundary-layer model was chosen, since the Nusselt equations are considered valid over the Eeynolds number range of interest, 0 to 1,500 (8). Also, observations (10,11) that flow in the entrance region is smooth and undisturbed, as compared with terminal flow at the same Reynolds numbers, supports the laminar flow model assumption. Figure 1 illustrates the assumed entrance region flow scheme for the steady, isothermal, laminar flow of an incompressible Newtonian fluid over the leading edge of a vertical plate.…”

Gaseous Nitrogen Oxide Absorption in a Sieve-Plate Column

“…Reaction of Nz04 and water proceeds by means of a fast pseudo-first-order liquid-phase reaction (Andrews and Hanson, 1961;Carberry, 1959;Caudle and Denbigh, 1953;Chilton and Knell, 1972;Corriveau, 1971;Dekker et al, 1959;Denbigh and Prince, 1947;Detournay and Jadot, 1973;Gerstacker, 1961;Hoftyzer and Kwanten, 1972;Koval and Peters, 1960;Kramers et al, 1961;Kameoka and Pigford, 1977;Moll, 1966;Peters and Holman, 1955;Peters et al, 1955;Sherwood et al, 1975;Wendel and Pigford, 1958). For NO2* partial pressures >0.01 atm, this is the predominant absorption reaction (Andrews and Hanson, 1961).…”