Preparation of an Energetic‐Energetic Cocrystal using Resonant Acoustic Mixing

Abstract

Resonant acoustic mixing (RAM) was applied to the preparation of an energetic‐energetic cocrystal comprised of CL‐20 and HMX in a 2 : 1 mol ratio. We have prepared the cocrystal using the RAM technology in a resource‐efficient manner providing near quantitative yield. The cocrystalline product from the RAM preparation is consistent with the product from solution crystallization.

Promising CL‐20‐Based Energetic Material by Cocrystallization

“…Similar challenges are encountered in both the pharmaceutical industry as well as the energetic community including scalability.T he use of energeticc ocrystals in field operations is directly restricted by the challenges associated with their production on large scale.T raditional methods of forming cocrystals largely rely on solution-phase crystallizationo rg rinding-assisted methods [14].S olution phase methodsc an be challenging to develop as they are prone to precipitation of the discrete coformers, solvateso f the coformers, other polymorphso ft he discrete coformers, and potentially disordered solids or undesired adducts.A lternatively,g rinding-based methods are restricted due to the sensitivity of energetic materials to stimuli. The effectivenesso fR AM for the preparation of pharmaceutical and energetic cocrystals has recently been demonstrated [15,16].H omogeneous mixing of multiple components with significantly different properties can be achieved throught he application of al ow-frequency acoustic field [17].T his mixing system is designedt ok eep the sample in resonance at 60 Hz with the ability to adjust the mixing intensity to accelerate the material from low intensity,n ear O-g acceleration, to high intensity mixing near 100-g acceleration.T he intimatec oupling of the payload to the mixing container and the continuous adjustment to keep the payload in resonance facilitates the transfer of the potential energy stored in the mixers mechanical system.T he propagation of the low frequency wave creates au niform shear field throughout the mixing vessel. Thus the methodi se fficient, rapid, and environmentally friendly [15,18].U nlike stirred tank vessels,t he mixing provided by resonant acoustics is directly scaleable to multi kilogram scale making it scale-transparent; i.e.…”

Rapid and High‐Yielding Formation of CL‐20/DNDAP Cocrystals via Self‐Assembly in Slightly Soluble‐Medium with Improved Sensitivity and Thermal Stability

“…However, its development has been hindered by the expensive spray dryer instrument and unclear formation mechanism. To the best of our knowledge, up to now the highest yield of CL-20/EMs cocrystal is from CL-20/HMX cocrystal (80 %~90 %, RAM method) [25] and CL-20/TNT cocrystal (88.3 %, electrospray deposition method) [22], respectively. In this work, we report a rapid and high-yielding preparation of CL-20/DNDAP cocrystal using self-assembly method.…”

Milling of Energetic Crystals with the LabRAM

“…Over the last decade, the Resodyn LabRAM acoustic mixer has been widely used for mixing of powders and for the pharmaceutical industry [18,19], yet its use as a vibratory mill has not been published extensively [20,21]. It has a long history of use for energetic materials processing that includes but is not limited to cocrystal synthesis [22,23], dry pyrotechnic powder mixing [24,25], rocket propellant mixing [26][27][28], and polymer bound explosives [29,30]. It must be noted that this milling technique is not safe for all energetic materials and a safety assessment of the energetic materials sensitivity to impact, friction, and ESD should be considered prior to milling.…”