| Popis: |
The vapour pressure and vapour compositions have been determined for the molten AlCl3-POCl3 system in the composition range 50–64 mol% AlCl3 and for temperatures in the range 170–270°C using a boiling point method and analyzing the boiled-off vapour after direct condensation. Knudsen effusion cell measurements of the solid AlCl3 · POCl3 compound have also been carried out. The melts are considered as molecular liquids consisting of Al2Cl6, Al2Cl6 · POCl3, AlCl3 · POCl3 and POCl3 molecules, respectively. The vapour species are Al2Cl6, AlCl3 · POCl3 and POCl3, A semiempirical thermodynamically based melt model has been developed explaining the vapour pressure minimum of acidic AlCl3-POCl3 melts and the published azeotrope at 51.5 mol% AlCl3. Thermodynamic data have been calculated. |
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