No abstract

Selected thermophysical properties are reported for VX (O-ethyl-S-[2(diisopropylamino)ethyl] methylphosphonothiolate) and its isomer, RVX (O-isobutyl-S-[2(diethylamino)ethyl] methylphosphonothiolate). Several properties have been reported previously for both compounds; the focus of the current work has been the measurement of additional properties and expansion of the experimental ranges for the existing data. This report consolidates and compares physical property data measured in our laboratory for both compounds. It is important to know the physical properties of these supertoxic materials accurately to understand quantitatively the threat posed by them during military conflict, perform testing of defensive equipment, and determine the necessity to perform decontamination procedures. Knowledge of the properties of these toxic materials facilitates the selection of lower-toxicity candidates to simulate their behavior during testing where the use of the toxic agent is inappropriate. The current work has employed standard American Society for Testing and Materials (ASTM) international methods, intact and modified, to measure physical properties of VX and RVX. Properties investigated in the present work include liquid density, viscosity, surface tension, flash point, vapor pressure, heats of vaporization, and volatility. We also report correlations determined from previously available and new data, where appropriate.

The vapor pressures of three 2-dialkyl aminoethanethiol compounds, 2-dimethyl aminoethanethiol (DMA), 2-diethyl aminoethanethiol (DEA), and 2diisopropyl aminoethanethiol (DIA), have been determined using complementary methods that enable data collection in the ambient and high temperature ranges using vapor saturation and differential scanning calorimetry, respectively. Previously published vapor pressure data for these materials are sparse, conflicting, and limited in the pressure ranges covered. This work greatly expands the experimental range and, owing to the good agreement obtained using complementary methods, significantly enhances confidence in the accuracy of the measured data. In addition to the observed data, this report includes derived properties, that is, temperaturedependent volatility and heats of vaporization.

No abstract

Triethyl phosphate (TEPO,, tri-npropyl phosphate (TPPO,, and diethyl malonate (DEM, are of considerable interest to the chemical defense community as nontoxic simulants for toxic chemical warfare agents. Vapor pressure data have been measured for TEPO at T = (271.25 to 480.15) K, for TPPO at T = (263.15 to 527.61) K, and for DEM at T = (265.15 to 471.25) K using a variety of standard methods that have been modified as necessary. The new data extend the range of vapor pressure data previously reported in the literature for each of the title compounds to subambient temperatures and to lower pressures by approximately 3 orders of magnitude for TEPO, 5 orders of magnitude for TPPO, and 1 order of magnitude for DEM. Vapor pressure data and derived properties, including volatility and temperature-dependent heats of vaporization are reported for TEPO, TPPO, and DEM along with comparisons to chemical warfare agent materials.