Phase diagrams, experimental determination

Fig. 8. Pseudo-binary (solvent-free)jy-x phase diagrams for determining which component is to be the distillate where (—) is the 45° line, (a) No solvent (b) and (c) sufficient solvent to eliminate the pseudo-a2eotiope where the distillate is component 1 and component 2, respectively (51) and (d) experimental VLE data for cyclohexane—ben2ene where A, B, C, and D represent 0, 30, 50, and 90 mol % aniline, respectively (52).

A phase diagram constructed from experiments on a series of poly(styrene)-poly(isoprene) (PS-PI) diblocks is presented in Fig. 2.2 (Khand-pur et al. 1995) and this will be used as a guide for the various microstructures. In order to determine a phase diagram experimentally, a variety of methods are... 

Solubility of racemic praziquantel was determined in MeOH and 2-PrOH in the temperature range between 0 °C and 40 °C. A ternary phase diagram of praziquantel enantiomers and the MeOH system was also determined (06CH259). The solubility phase and binary melting-point phase diagrams were determined. Experimental and predicted aqueous solubility of praziquantel was reported (07CPB669,08SQE191). Dissolution of praziquantel... 

The experimental procedures described in this paper are mainly concentrated on the preparation of membranes from various polymer-solvent systems by precipitation in a nonsolvent, generally water. The membranes are then characterized in terms of their transport properties and structures. Furthermore, the three-component phase diagrams are determined for various polymer-solvent-precipitant systems. 

Liu] Liu, S., Hamaguchi, Y, Kuwano, H., Experimental Determination of the Phase Boundaries of Intermetallic Compounds in the Ternary Fe-Cr-Mo System (in Japanese), J. Jpn. Inst. Met., 50, 1023-1031 (1986) (Phase Diagram, Phase Relations, Experimental,, , 17) [1988And] Andersson, J.-O., Lange, N., An Experimental Study and a Thermodynamic Evaluation of the Fe-Cr-Mo System , Metall Trans., 19A, 1385-1394 (1988) (Phase Diagram, Experimental, Calculation, Assessment,, , 32)... 

Pou] Poubeau, J.J., Bigot, J., Determination of Carbon Solubihty in Chromium with Measurement of Electrical Resistivity at Low Temperature (in French), Acta Metall., 33(6), 1137-1141 (1985) (Crys. Stmcture, Phase Diagram, Experimental, 20)... 

Although prewetting transitions are inextricably connected with first-order wetting transitions, they have proven very difficult to observe experimentally for solid-vapor interfaces. The few systems for which the phenomenon has been observed include He films on cesium (Rutledge and Taborek, 1992), H2 films on rubidium (Cheng et al., 1993), mercury films on sapphire (Hensel and Yao, 1994 Yao and Hensel, 1996), and mercury films on niobium (Kozhevnikov et al., 1997). In these cases, complete prewetting phase diagrams were determined. 

Alkanes are thermally unstable above approximately 650 K, which makes experimental determination of the critical point of alkanes longer than decane (Cio) extremely difficult. The longer alkanes, however, are present in mixtures of practical importance for the petrochemical industry. In these mixtures, the number of components can be so large that it is not practical to determine all phase diagrams experimentally. One therefore has to rely on predictions made by equations of state. The parameters of these equations of state are directly related to the critical properties of the pure components. Therefore, the critical properties of the long chain alkanes are used in the design of petrochemical processes, even if they are unstable close to the critical point. Unfortunately, experimental data are scarce and contradictory, and one has to rely on semi-empirical methods to estimate the critical properties. ... 

Pal] Palm, M., Inden, G., Experimental Determination of Phase Equilibria in the Fe-Al-C System , Intermetallics, 3, 443-454 (1995) (Phase Relations, Phase Diagram, Experimental,, 33)... 

There are many types of phase diagrams in addition to the two cases presented here these are summarized in detail by Zief and Wilcox (op. cit., p. 21). Solid-liquid phase equilibria must be determined experimentally for most binaiy and multicomponent systems. Predictive methods are based mostly on ideal phase behavior and have limited accuracy near eutectics. A predic tive technique based on extracting liquid-phase activity coefficients from vapor-liquid equilib-... 

Fig. 4. Provisional binary phase diagram for K Cao at 1 atm pressure. Experimentally determined temperatures are indicated, while unknown temperatures of predicted transformations are labeled Ti,..., Ta. [57].

Phase diagrams give valuable information about the compounds that can form in a system of components. These compounds can then be prepared and studied. For the experimental determination of phase diagrams the following methods are used. In differential thermal analysis (DTA) a sample of a given composition is heated or cooled slowly... 

The topological transformations in an incompatible blend can be described by the dynamic phase diagram that is usually determined experimentally at a constant shear rate. For equal viscosities, a bicontinuous morphology is observed within a broad interval of the volume fractions. When the viscosity ratio increases, the bicontinuous region of the phase diagram shrinks. At large viscosity ratios, the droplets of a more viscous component in a continuous matrix of a less viscous component are observed practically for all allowed geometrically volume fractions. 

Chapter 18 - The determination region of solubility of methanol with gasoline of high aromatic content was investigated experimentally at temperature of 288.2 K. A type 1 liquid-liquid phase diagram was obtained for this ternary system. These results were correlated simultaneously by the UNIQUAC model. By application of this model and the experimental data the values of the interaction parameters between each pair of components in the system were determined. This revealed that the root mean square deviation (RMSD) between the observed and calculated mole percents was 3.57% for methylcyclohexane + methanol + ethylbenzene. The mutual solubility of methylcyclohexane and ethylbenzene was also demostrated by the addition of methanol at 288.2 K. 

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