Preparation of Dinitrogen Trioxidefor Organic Synthesis: A Phase Equilibrium Approach

Dinitrogen trioxide (N2O3) is a potent nitrosating agent featured with high reactivity and appealing atom economy. Because of its instability and the entanglement of chemical and phase equilibria, N2O3 has rarely been utilized in organic synthesis as a stock reagent with well-defined composition. In this review,the preparations of pure N2O3 and its concentrated solution (>0.1 M) are discussed from the aspect of phase equilibrium. Understanding the physical and chemical characteristics of N2O3, along with how reaction parameters (temperature, pressure, molar ratio) interact, plays a crucial role in managing the concentration of N2O3 in the liquid phase. This control holds practical significance in achieving quantitative reactions.