A process for N-butyl-N-(2-nitroxyethyl)nitramine (BuNENA) was investigated: Step 1. involves N-butyl-ethanolamine addition to 98% HNO3 to form a salt mixture, Step 2 is addition of acetic anhydride/acetyl chloride catalyst to the salt mixture. A number of potential intermediates, by-products, and decomposition products from this process were identified/synthesized for use as analytical standards. BuNENA process reaction pathways/mechanisms were elucidated, including the nature of the amine salt solution formed in Step 1. In addition, potential pathways that could account for by-product formation were elaborated. A study of the consumption of acetyl nitrate in Step 2 was undertaken to prevent its build-up.