Knowledge of the physical properties of materials is critical for understanding their behavior in the environment as well as in the laboratory. Vapor pressure is an important physical property for a wide variety of chemical defense-related applications, including estimation of persistence, prediction of downwind time-concentration profiles after dissemination, generation of controlled challenge concentrations for detector testing, evaluation of toxicological properties, and assessment of the efficiency of air filtration systems.

Structures and chemical names of title compounds.

The U.S. Army Edgewood Chemical Biological Center (Aberdeen Proving Ground, MD) has a long history of interest in quantification of the physical properties of chemical warfare agents (CWAs) and related materials, including the development of correlations to enable the accurate prediction of values at untested temperatures. Recent efforts have focused on investigation and documentation of vapor pressure and properties that were derived from such data, including temperature correlations, volatility, and temperature-dependent enthalpy of volatilization (vaporization for liquids and sublimation for solids) for CWAs and related compounds.

In addition to agents, recent work has focused on determination of the vapor pressure of agent precursors, degradation products, and simulants using two different ASTM International methods that are based on the differential scanning calorimetry (DSC) “pinhole” technique and vapor saturation (or transpiration). This research documents vapor pressure measurements, correlations, and derived properties for the organophosphorus G- and V-agent-related degradation products and simulants, whose structures, chemical names, Chemical Abstract Services (CAS) Registry Numbers, chemical formulas, and molecular weights are shown in the accompanying figure.

This work was done by Ann Brozena, James H. Buchanan, Patrice L. Abercrombie-Thomas, and Kenneth B. Sumpter, Research and Technology Directorate; Barry R. Williams, Leidos, Inc.; and David E. Tevault, Joint Research and Development, Inc. for the Defense Threat Reduction Agency. DTRA-0007

This Brief includes a Technical Support Package (TSP).
Vapor Pressure Data and Analysis for Selected Organophosphorous Compounds: DIBMP, DCMP, IMMP, IMPA, EMPA, and MPFA

(reference DTRA-0007) is currently available for download from the TSP library.

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