(544i) Nanoparticulation Of CL20: A Feasibility Study To Produce Nanoparticles Of CL20 With Supercritical Fluids

The Army is interested in developing green processes to support its industrial operations. Developing processes without the use of toxic solvents and chemicals is a major focus of the effort in developing the green processes. This presentation summarizes a recent study to develop nanoparticles of CL20 (2,4,6,8,10,12-Hexanitro-2,4,5,8,10,12-hexaazaisowurtzitane) using supercritical processes. In order to generate the desired nanocrystalline particles, the crude CL20 is dissolved into an environmentally benign solvent such as supercritical carbon dioxide and then condensed to ultrafine particles by reducing the pressure and temperature of the mixture. It is desired to have at least have estimates of supercritical solubility of CL20 in carbon dioxide, prior to the nanoparticulation experiments. Estimation of solubility of CL20 in supercritical carbon dioxide was carried out using the Peng-Robinson cubic equation of state. Solubility was predicted over the temperature range of 305.15 to 368.15 K and over the pressure range of 74 to 150 atm. In general, as the temperature increases, the solubility decreases, while as the pressure increases, the solubility increases. For CL20, the estimated vapor pressures are extremely small, on the order of 10-18 at ambient temperature, increasing to 10-13 at 368.15 K. Thus, the predicted solubilities are also small (range of 10-13 to 10-6), with the highest solubility predicted for 308.15 K (35?aC) and 150 atm. Nanoparticulation experiments were conducted using a supercritical extraction apparatus supplied by Thar Technologies, Inc. Results of CL20 solubility predictions and SEM and XRD characterization of the nanoparticles will be presented.