Decomposition of Methyl Nitrite in Solutions and Soils

Abstract

AbstractThe role of hydrolysis as a process affecting the concentration of CH3ONO in the soil atmosphere was investigated by measuring the sorption of CH3ONO and the formation of NO‐2 and NO‐3 in two soils (−33‐kPa soil water potential) and three solutions in the dark at 20°C for 10 h. Soil pH and the pH of distilled H2O decreased on absorption of CH3ONO. In acidic solutions (distilled H2O and 0.1 M H2SO4), > 90% of CH3ONO was recovered as NO‐3, whereas to an alkaline soil and 0.2 M NaOH, > 80% was recovered as NO‐2. Only 0 to 7% of CH3ONO remained in the atmosphere. In an acid soil only 50% of CH3ONO was recovered as [CH3ONO + NO‐2 + NO‐3]‐N. Recoveries of N in γ‐irradiated and nonirradiated soils did not differ significantly. The data indicate that CH3ONO was rapidly hydrolysed in solutions and in soils [CH3ONO + H2O ⇌ CH3OH + HNO2], and that NO‐3 formed via the self‐decomposition of HNO2. The low recovery of N in the acid soil may have been due to the participation of HNO2 in chemodenitrification reactions. The rapid hydrolysis of CH3ONO is likely to inhibit the emission of CH3ONO formed in soils, and to cause the sorption of CH3ONO evolved from soils in closed systems.