2019 AIChE Annual Mtg: Designing a Continuous Flow System to Safely Nitrate Alkylamines to Nena’s

On Wednesday, November 13, Jerry S. Salan, Trevor M. Rosensohn, Andrew G. Pearsall, Matthew L. Jorgensen, and David J. am Ende presented 'Designing a Continuous Flow System to Safely Nitrate Alkylamines to Nena’s' at the 2019 AIChE Annual Meeting in Orlando, FL.

Abstract

Nitroethylnitramines (NENA-compounds) are useful in propellants and explosives as energetic plasticizers. The NENA compounds of interest include methyl, ethyl, propyl, butyl NENA’s. These Alkyl-NENA’s contain a nitrate ester (-ONO2) as well as a nitramino (-NH-NO2) functional groups and are known to effectively plasticize cellulosic polymers such as nitrocellulose. Manufacture of NENA compounds presents significant process safety challenges due to the potential energy of the materials, thermal stability, and the highly exothermic reactions. Previous investigators have provided stern warnings of fire and “spark spheres” forming in the reactors at laboratory scale. Highly exothermic reactions pose significant scaleup challenges that are compounded with unstable, high energy products. These challenges can be addressed with chemical engineering solutions that scale such as continuous processing. The various phases of the two-step nitration have been studied for years with a focus on safety. Heat flow calorimetry, flow NMR, off-line analytics (e.g. HPLC, GC), and in situ spectroscopy contributed to establishing reaction kinetics and overall process understanding to safely produce this family of compounds. In addition, critical safety data were generated using thermal analysis (e.g. DSC, TSu, ARC) of the various processing streams. The combined results and design of a safe continuous manufacturing process for NENA’s will be discussed.