Synthesis of BuNENA in a continuous flow microreactor

In order to improve process safety, product purity, and production efficiency in the synthesis of N-n-butyl-N-(2-nitroxy-ethyl)nitramine (BuNENA), a two-stage continuous flow microreactor system was constructed by sequentially connecting the self-designed heart-shaped channel microreactor and the caterpillar microreactor. n-Butylethanolamine was used as the raw material, nitric acid and acetic anhydride were used as the nitrating agents. The results showed that when the flow rate of n-butylethanolamine was 1.00 mL.min^− 1, the temperature of the heart-shaped channel microreactor was 10 ℃, the temperature of the caterpillar microreactor was 35 ℃, the molar ratio of ZnCl₂ to n-butylethanolamine was 2%, the molar ratio of nitric acid to n-butylethanolamine was 2.4, and the molar ratio of ZnCl₂ to n-butylethanolamine was 2.4, the result was best. Under the conditions, the reaction time was shortened to 300 s, the purity of BuNENA was up to 98.1%, and the yield was 87.1%.