Solubility determination of TNT and wax and their fractionation from an explosive material using a supercritical fluid

The solubilities of 2,4,6-trinitrotoluene (TNT) and wax have been measured in supercritical carbon dioxide (CO2) at three pressures and temperatures under static conditions. The concentrations of each component were determined off-line via ultraviolet (TNT) and evaporative light scattering (wax) detection. The solubility of TNT was an order of magnitude higher than that of wax. Gas chromatographic assay of the wax extract revealed that only the lower molecular weight components dissolved. Fractionation of the TNT and wax from an explosive material referred to as Composition B was attempted by making incremental increases in CO2 density. Composition B contains 59.5% cyclotrimethylene triamine (RDX), 39.5% TNT, and 1% wax. While TNT and wax could be easily isolated from nitramine RDX, attempts to separate TNT from wax were not totally successful. More specifically, the initial fractions contained the lower molecular weight wax components in addition to major amounts of TNT. Since the percentage of TNT was approximately 50 dimes the amount of wax, later fractions were 100% TNT although most of the TNT was removed at the lower densities.