Orbital ATK
1
MICROFLUIDIC SYNTHESIS OF ENERGETIC COMPOUNDS
Dr. Joe Scavuzzo and Dr. Melissa Mileham
Abstract #20271
Orbital ATK
Corinne, Utah
ABSTRACT
Microfluidic synthesis is the use of microliter scale flow reactors to manipulate reactive
liquids or solutions to produce chemical transformations. Microfluidic synthesis
processes have some advantages over traditional batch processes, particularly when
producing energetic molecules. For example, microfluidic reactors contain only
microliters of reactive solution, which greatly reduce risks associated with large volumes
of energetic material. Further, because of the high surface area-to-bulk ratio in
microfluidic reactors, heat is efficiently transferred away from the system. This is of
particular importance for the synthesis of energetic molecules where exothermic
nitrations and oxidations are common. The simplicity of microfluidic reactors also allows
for easy scale-up and automation for remotely controlled processes. The present work
deals with the design and fabrication of a microfluidic reactor used to produce energetic
molecules. A nitrated precursor for an energetic polymer was chosen as the target
molecule. The synthetic process contains two steps where organic molecule X1 is first
nitrated to produce NO2-X1. In the second step, NO2-X1 undergoes an exothermic
rearrangement to give the final product, NO2-X2. Each step was performed and
optimized individually on the microfluidic reactor. The optimized conditions were then
used to perform the two steps in series on a single reactor.
INTRODUCTION
MICROFLUIDIC REACTOR BACKGROUND
Microfluidic reactors manipulate reactive liquids or solutions to produce chemical
transformations under geometrically constrained environments with internal dimensions
on the scale of micrometers.
[1]
Microfluidic reactors contain microliter volumes of reaction
solution, therefore only micrograms of energetic material are in process at any given
time. This is particularly advantageous during the development stage of a new chemical
process. Developmental operations involving new energetic materials and/or processes
are inherently higher risk because of unknown behaviors and the potential for explosion.
Accepting these risks can be reasonable if the consequence of an unexpected behavior
is low. Because the process volumes of microfluidic reactors are restricted to
microliters/gram scale, the consequences of unexpected behavior are more acceptable.
Microfluidic reactors provide some unique advantages over traditional synthesis
methods. The reactor’s high surface area-to-volume ratio allows for very efficient heat
transfer from the reactor to the reactor’s external environment. Highly exothermic
reactions are commonplace in energetic material synthesis and efficient heat transfer
translates to safer operations by mitigating the risk of self-heating runaway reactions.
