Vapor Pressure of Solid 1,4-Dithiane

Abstract

The vapor pressures of low-volatility chemical warfare (CW) agents, their byproducts and degradants, and simulants are important physical data that are needed for accurate vapor generation, for filter modeling and testing, and for assessing the environmental fate of the materials. This report documents the measurement of the vapor pressure of 1,4-dithiane (DTH), a byproduct associated with vesicant chemical warfare agent bis-2-chloroethyl sulfide (HD), in the range of (296.65 to 376.95) K. By combining our measurements with a study of the thermodynamic properties of the compound in the subambient range, we were able to calculate Antoine parameters that can be used to extend estimates of the vapor pressure from T ) (256.95 to 376.95) K. We have calculated a value of 10.6 Pa for the vapor pressure of the compound at 298.15 K. This contrasts with the accepted value of 107 Pa.

Ambient Temperature Vapor Pressure and Adsorption Capacity for (Perfluorooctyl) Ethylene, 3-(Perfluorobutyl)propanol, Perfluorohexanoic Acid, Ethyl Perfluorooctanoate, and Perfluoro-3,6-dioxaheptanoic Acid

“…The relative expanded uncertainty, based on eq is U normalp = false( U normalT + U normalm + U v normalc + U normalP false) 1 / 2 estimated to be 0.52 %. The uncertainty of the measurements is similar to previous work. , …”

“…In these experiments, there are four different areas where the uncertainty can enter: (1) the temperature of the water bath T bath , (2) the weighing of the saturator cell which is related to the moles of chemical, n chem , (3) the uncertainty in the mass flow rate n carrier , and (4) the ambient pressure P ambient . The thermometer used has a stated accuracy of ± 0.1 K. As discussed by Williams et al 42 the uncertainty is difficult to directly determine because of the logarithmic function of temperature. However, we will estimate in the same way by calculating the differences in the vapor pressure computed from Antoine coefficients by a change of 0.1 K at a central temperature.…”

Vapor Pressure of Triethyl and Tri-n-Propyl Phosphates and Diethyl Malonate

“…The standard uncertainty u for temperature, u ( T ), and the combined expanded uncertainty U c for pressure, U c ( P ) (0.95 level of confidence), are listed at each experimental temperature in Tables , , and . Analysis of these uncertainties for data measured using vapor saturation by mass loss, vapor saturation by trap-and-purge, and thermal analysis methods has been addressed in detail in previous reports from our laboratory. ,, The error in the determination of vapor pressure for data generated by the Knudsen effusion method has been estimated by Swan and Mack to “seldom be much larger than 1 or 2 %”. Our method is similar to that of Swan and Mack and on the basis of the accuracy observed for naphthalene data, we believe a combined expanded uncertainty for pressure U c ( P ) of 0.02 is a good estimate for the current Knudsen effusion data.…”

Vapor Pressure of 2-Dialkyl Aminoethanethiols

“…The procedures used to generate the saturated vapor stream are the same as those used previously. − ,− A sample of saturator effluent was analyzed by GC to determine the purity of analyte in the sample. Saturator effluent vapor analyses revealed no observable impurities.…”

“…In this case, gas chromatographic (GC) analysis was used only to verify the purity of the compound in the vapor. This approach, which we have used to determine the vapor pressure of dimethyl methylphosphonate, solid 1,4-dithiane, 2-chlorovinyl dichloroarsine, and O,S-diethyl methylphosphonothioate, is useful for high purity compounds and when the expected change in mass during an individual run exceeds approximately 50 mg. The second method used in the present work employs the differential scanning calorimetry (DSC) pinhole technique…”