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Abstract  

Tri-iso-amyl phosphate is an alternate solvent, proposed in literature as an alternate to the PUREX/UREX solvent tri-n-butyl phosphate for better physical properties. Its PVT properties and accurate expression for estimation of its vapour pressure are not available in the literature. Recently PVT properties of TiAP were estimated by authors and its vapour pressure was measured in a ASTM certified vapor pressure measurement system at temperatures ranging from 273.15 to 373.15 K. In this paper, results of these studies are presented.

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Thermogravimetry and vapor pressure moisture

Applications to determination of residual moisture in BCG vaccine

Journal of Thermal Analysis and Calorimetry
Authors: J May, A Del Grosso, N Etz, R Wheeler, and L Rey

Abstract  

Thermogravimetry (TG), thermogravimetry/mass spectrometry (TG/MS), and loss-on-drying methodology are used to provide residual moisture results for freeze-dried biological products regulated by the US Food and Drug Administration. Residual moisture specifications must be met in order to ensure freeze-dried biological product potency and stability throughout the licensed product's shelf life. TG, TG/MS, loss-on-drying and vapor pressure moisture measurements are compared for a BCG Vaccine. Comparisons are made between residual moisture data for the freeze-dried cake and vapor pressure moisture determinations in the space above the freeze-dried cake in the final container. Vapor pressure moisture precision data is presented for α-interferon and BCG vaccine. Impact of residual moisture and vapor pressure moisture upon product stability is presented.

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well as measurement of the vapor pressure of substances [ 16 – 24 ]. Evaporation can be stated as the transition from the liquid phase to the vapor phase, without a change in chemical composition. Several factors such as vapor pressure of the

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Abstract  

The vapour pressures of six para-substituted benzoic acids were measured using the Knudsen effusion method within the pressure range (0.1–1 Pa) in the following temperature intervals: 4-hydroxybenzoic acid (365.09–387.28) K; 4-cyanobenzoic acid (355.14–373.28) K; 4-(methylamino)benzoic acid (359.12–381.29) K; 4-(dimethylamino)benzoic acid (369.29–391.01) K; 4-(acetylamino)benzoic acid (423.10–443.12) K; 4-acetoxybenzoic acid (351.28–373.27) K. From the temperature dependence of the vapour pressure, the standard molar enthalpy, entropy and Gibbs energy of sublimation, at the temperature 298.15 K, were derived for each of the studied compounds using estimated values of the heat capacity differences between the gaseous and the crystalline phases. Equations for estimating the vapour pressure of para substituted benzoic acids at the temperature of 298.15 K are proposed.

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dependence of the saturated vapor pressure was measured by the flow method and the standard thermodynamic parameters Δ H T and Δ S T o were determined for the vaporization process of the compounds. The molecule packing in the crystals was considered using

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Abstract  

For a large number of DSC calibration substances the vapour pressure at room temperature or at transition temperature (whichever is the highest) is given. It is important to know the vapour pressure of substances, because a DSC measurement on a substance with a high vapour pressure requires encapsulation of the substance in a hermetically sealed crucible to prevent evaporation. Because the calibration procedure must be performed using the same type of sample pan as will be used during the actual measurements, the presented information allows one to decide which calibration substances and/or what type of sample pan should be used for calibration.

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Abstract  

A new pressure DSC module (Mettler DSC27HP) and its abilities for vapor pressure determination in the range of subambient pressure to 7 MPa are presented. To compare the new to an established method, vapor pressures of caffeine, naphthalene and o-phenacetin have been determined both by pressure DSC and the Knudsen effusion cell method. These results, including the derived heats of evaporation and heats of sublimation, are compared to literature values.

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Abstract  

The Modified Entrainment Method developed by Faktor et al. [1] is an attractive yet not very popular method to determine vapour pressures in the range of 0.002 to 0.1 bar at 10–1000°C. The method consists of evaporating a solid or liquid from a small bulb through a capillary into a flowing inert gas, e.g. argon. The vapour pressure of the sample is related to the rate of evaporation and some easily controlled experimental parameters. In the present paper a new convenient experimental set-up is described and its use to study the decomposition of metal complexes is illustrated.

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Abstract  

Phenyl trifluoromethyl sulfone (FS-13) is a polar diluent, proposed in literature as an alternate to nitrobenzene, in UNEX/HCCD-PEG processes for better physical properties. Its PVT properties and accurate expression for estimation of its vapour pressure are not available in the literature. Recently PVT properties of FS-13 were estimated by authors and its vapour pressure was experimentally measured at temperatures ranging from 263.15 to 363.15 K. In this paper, results of these studies are presented.

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Abstract  

The temperature dependency of the saturated vapor pressure of Ir(acac)3 has been measured by the method of calibrated volume (MCV), the Knudsen method, the flow transpiration method, and the membrane method. The thermodynamic parameters of phase transition of a crystal to gas were calculated using each of these methods, and the following values of ΔH T 0 (kJ mol−1) and ΔS T 0 (J mol−1K−1), respectively, were obtained: MCV: 101.59, 156.70; Knudsen: 130.54, 224.40; Flow transpiration: 129.34, 212.23; Membrane: 95.45, 149.44 Coprocessing of obtaining data (MCV, flow transportation method and Knudsen method) at temperature ranges 110−200C as also conducted:ΔH T 0 =127.92.1 (kJ mol−1 ); ΔS T 0 =215.25.0 (J mol−1 K−1 ).

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