Measurement Of The Vapor Pressures Of TNT, 2,4-DNT, 2,6-DNT, And EGDN
A method to measure the vapor pressure of 2,4,6-trinitrotoluene (118967) (TNT), 2,4-dinitrotoluene (121142) (2,4-DNT), 2,6-dinitrotoluene (606202) (2,6-DNT), and ethylene-glycol-dinitrate (628966) (EGDN) was assessed. An equilibrium vapor concentration was generated by passing dry nitrogen through a spiral glass tube containing the explosive compound dispersed in an inert support. The flow rate of nitrogen was sufficiently slow to allow saturation with the explosive vapor. To measure the mole fraction of vapor a known volume was collected on glass wool. The absorbed explosive was then eluted with a solvent. The mole fraction of the explosive was measured by comparing the chromatographic peak area with that obtained from a standard solution. The solvents used were benzene, acetone, and spectrograde quality cyclohexane. Measured vapor pressures at various temperatures were calculated and corresponding temperature pressures, obtained by least squares equations, were monitored. Results indicated that the vapor pressure of 2,4-DNT was about 10 times greater than the expected value. TNT, 2,6-DNT and EGDN were in agreement with previous values. The enthalpies of sublimination of EGDN, TNT, and 2,4-DNT were in good agreement with previously reported values. The author concludes that vapor pressures are generally in agreement with previous pressure measurements using this method, with the exception of 2,4-DNT.