Experimental Cloud-Points for Polybutadiene + Light Solvent and Polyethylene + Light Solvent Sys-tems at High pressure

JUAN M. MILANESIO; GUILLERMO MABE; ANDRES CIOLINO; LIDIA MARÍA QUINZANI; MARCELO S. ZABALOY

JOURNAL OF SUPERCRITICAL FLUIDS

ELSEVIER SCIENCE BV

Año: 2010 vol. 55 p. 363 - 372

0896-8446

The hydrogenation of unsaturated heavy compounds is conventionally carried out in the presence of two fluid phases, because the immiscibility in the binary subsystem ´hydrogen + heavy substrate´ cannot be overcome by adding a standard solvent. Using a supercritical or quasicritical solvent, we can have the hydrogen and the unsaturated heavy substrate dissolved in a single phase. This implies higher mass transfer rates and consequently less time required for complete hydrogenation of the double bonds. To select the operating conditions of a supercritical reactor, it is convenient to determine the phase boundaries of the subsystems ´solvent + hydrogen´ and ´solvent + heavy compound´. In this work, we obtain experimental cloud points, i.e. liquid-liquid boundaries at constant composition, for binary systems made of polybutadiene (PB) or polyethylene (PE) and a light solvent (propane, dimethyl ether or diethyl ether). The results of this work are a part of a phase equilibrium engineering study in which we determine the single-phase boundary for ´polymer + solvent´ systems. The final aim is to establish the technical feasibility of hydrogenating PB using supercritical or quasicritical fluids as reaction media. This includes the need for determining whether the hydrogenation product, i.e. the partially (or fully) hydrogenated PB, will remain solubilized in the reaction media.