High-pressure hydrogenation of polybutadiene at conditions found from phase transitions of the non-reactive system polybutadiene + n-pentane + dimethyl ether + hydrogen

MATIAS MENOSSI; JUAN M. MILANESIO; ANDRES CIOLINO; LIDIA MARÍA QUINZANI; MARCELO S. ZABALOY

Rio de Janeiro

Congreso; X Congresso Brasileiro de Termodinâmica Aplicada; 2019

Universidad Federal de Rio de Janeiro

Linear low-density polyethylene (LLDPE) with a polydispersity index (PD) close to unity can be obtained by hydrogenating polybutadienes (PBs) with narrow molecular weight distributions.  The goals of this work are the following: (a) to obtain new PVT data, at set T, global composition and global density, in a visual constant volume equilibrium cell, for the quaternary system PB + n-pentane (C5) + dimethyl ether (DME) + H2, in the absence of catalysts. (b) to carry out PB hydrogenation experiments in the presence of a catalyst and of a single fluid phase at conditions based on the PVT information gathered in (a). The cell makes possible to observe the number of phases of the system. In a non-reactive experiment, the constant volume cell, whose internal volume is known, is loaded with a known amount of a known composition mixture. Next, the pressure is measured at a set temperature. A temperature range of interest is covered. The measured pressure versus temperature curve is both, isoplethic and isochoric. A slope discontinuity in the curve implies a phase transition. Phase equilibrium results are presented for the non-reactive system, and hydrogenation results are reported for the reactive system.