Table of Contents
Journal of Thermodynamics
Volume 2011, Article ID 282354, 5 pages
Research Article

Phase Behaviour of the System Propene/Polypropene at High Pressure

1Lummus Novolen Technology GmbH, Gottlieb-Daimler-Strasse 8, 68165 Mannheim, Germany
2Institute of Chemical Engineering and Macromolecular Science, Darmstadt University of Technology, Petersenstraße 20, 64287 Darmstadt, Germany
3ExxonMobil Chemical, 5200 Bayway Drive, Baytown, TX 77520-2101, USA
4ExxonMobil Chemical Europe Inc., Hermeslaan 2,1831 Machelen, Belgium

Received 15 April 2011; Accepted 1 June 2011

Academic Editor: Tiziana Fornari

Copyright © 2011 Oliver Ruhl et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The phase behaviour of mixtures of supercritical propene and a number of polypropenes, which have a similar density but significantly different molecular weights and tacticities, was investigated in a broad range of polymer weight fractions and temperatures at high pressures. The cloud-point pressures were measured optically, using a view cell which was equipped with two windows made of synthetic sapphire and a metal bellows to accurately adjust the pressure. The cloud-point pressures were found in the range from 29 to 37 MPa decreasing with increasing polymer weight fraction and increasing with increasing temperature and polymer molecular weight. The critical weight fraction was found below 2 to 6 wt.-%. Whereas the cloud-point pressures of atactic and syndiotactic samples were high and very similar, the isotactic species exhibit distinctly lower values. The results, extrapolated to lower temperatures, show good agreement with the literature data.