Equilibrium Phase Diagrams fromAb Initio Thermodynamics

2009 ◽  
pp. 163-177
Keyword(s):  
Phase Diagrams ◽  
Equilibrium Phase

scholarly journals Effect of Cation Structure in Quinolinium-Based Ionic Liquids on the Solubility in Aromatic Sulfur Compounds or Heptane: Thermodynamic Study on Phase Diagrams

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5687
Author(s):  
Marta Królikowska ◽  
Marek Królikowski ◽  
Urszula Domańska
Keyword(s):  
Ionic Liquids ◽  
Phase Diagrams ◽  
Binary Systems ◽  
Ambient Pressure ◽  
Equilibrium Phase ◽  
Sulfur Compounds ◽  
Solution Temperature ◽  
Organic Sulfur Compounds ◽  
Nrtl Equation ◽  
Solid Liquid

Experimental and theoretical studies on thermodynamic properties of quinolinium-based ionic liquids (ILs) based on bis(trifluoromethylsulfonyl)imide anion (namely N-butyl-quinoloinium bis(trifluoromethylsulfonyl)imide, [BQuin][NTf2], N-hexylquinoloinium bis(trifluoromethyl-sulfonyl)imide, [HQuin][NTf2], and N-octylquinoloinium bis(trifluoromethyl-sulfonyl)imide, [OQuin][NTf2]) with aromatic sulfur compounds and heptane, as a model compound of fuel were examined in order to assess the applicability of the studied ionic liquids for desulfurization of fuels. With this aim, the temperature-composition phase diagrams of 13 binary mixtures composed of organic sulfur compounds (thiophene, benzothiophene, or 2-methylthiophene) or heptane and ionic liquid (IL) were investigated at ambient pressure. A dynamic method was used to determine the (solid–liquid) equilibrium phase diagrams in binary systems over a wide composition range and temperature range from T = 255.15 to 365.15 K up to the fusion temperature of ILs. The immiscibility gap with an upper critical solution temperature (UCST) was observed for each binary system under study. The influence of the alkane chain length of the substituent on the IL cation and of the sulfur compounds (the aromaticity of the solvent) was described. The experimental (solid + liquid) phase equilibrium dataset were successfully correlated using the well-known NRTL equation.

Slag Investigations from Bronze Age Copper Smelting Sites

2017 ◽  
Vol 891 ◽  
pp. 608-612 ◽  
Author(s):  
Roland Haubner ◽  
Susanne Strobl
Keyword(s):  
Phase Diagram ◽  
Chemical Composition ◽  
Phase Diagrams ◽  
Bronze Age ◽  
Equilibrium Phase ◽  
Eastern Alps ◽  
Copper Production ◽  
Copper Smelting ◽  
Smelting Process ◽  
Melting Properties

During the Bronze Age intensive mining and smelting activities for copper production took place in the Eastern Alps. To get information about the copper smelting process, the elemental compositions of slags are marked in equilibrium phase diagrams (e.g. FeO-CaO-SiO2) and so the melting properties can be estimated. Doing so you have to keep in mind that slags have complex compositions and phase diagrams are available for three compounds only. For the analytical measurements it has to be ensured that only molten parts of the slag are measured and not contamination of other ambient material. Spot and area measurements by SEM-EDX are useful to get realistic data. In this case a complete correlation between the image of the analyzed area, the microstructure and the chemical composition of the sample is necessary. For marking spots in the phase diagram the calculation method has to be described exactly. For our results we calculated the ratio FeO-SiO2-CaO(+MgO+Al2O3). From the morphology of the observed phases, their chemical composition and the data from the phase diagram a solidification sequence can be suggested. We recommend this method because measurements by e.g. XRF provide rather general composition values. If the slag samples are inhomogeneous, unrealistic melting points are read from the phase diagram. Inhomogeneities can be caused by soil contaminations, which are not part of the molten slag, or by corrosion, when some phases were attacked and changed during storage in soil.

scholarly journals Computational Strategies for Mapping Equilibrium Phase Diagrams

ChemInform ◽  
2003 ◽  
Vol 34 (45) ◽  
Author(s):  
Alastair D. Bruce ◽  
Nigel B. Wilding
Keyword(s):  
Phase Diagrams ◽  
Equilibrium Phase

Accurate Calculation of the Non-Variant Points of Equilibrium Phase Diagrams by Using the ESTPHAD Method

2012 ◽  
Vol 729 ◽  
pp. 448-454 ◽  
Author(s):  
Tamás Mende ◽  
András Roósz
Keyword(s):  
Phase Transitions ◽  
Phase Diagrams ◽  
Equilibrium Phase ◽  
High Accuracy ◽  
Exact Calculation ◽  
Accurate Calculation

Certain phase transitions take place at a given temperature in the equilibrium phase diagrams, the values of their temperatures can exactly be measured so it is an essential task to calculate these values by a high accuracy. New parameters were introduced into the ESTPHAD equation for calculating the so-called non-variant points. By using the ESTPHAD method, the accuracy of calculations are compared to the data used for the calculations so the exact calculation of the temperatures of non-variant points are defined as compared to the data used for the calculations.

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