GB907579A - A process for the polymerisation or copolymerisation of an olefinically unsaturated hydrocarbon(s) - Google Patents

Abstract

Olefins are polymerized to polymers having a low degree of crystallinity, in the gas phase and in the absence of a liquid phase, with the aid of a catalyst consisting of (a) one or more trihalides of titanium and/or vanadium and (b) an aluminium compound containing in the molecule aluminium alkyl and aluminium alkoxy linkages or a mixture of such compounds, or a mixture of aluminium trialkyl compounds with such compounds or with aluminium trialkoxy compounds. Specified monomers are ethylene, propylene, butylene-1 and butadiene, and mixtures of ethylene and propylene, and propylene and butylene-1. The catalyst may be present in a finely-divided state in admixture with solid inert diluents, e.g. silica gel, kieselguhr, alumina, calcium oxide, magnesium oxide, sodium chloride, calcium carbonate or polymers of the type being prepared, and may be maintained in a fluidized state during polymerization. At least a part of the aluminium compound may be added during polymerization, or it may be absorbed on an inert diluent before contacting with the trihalide. The trihalide may also be supported, e.g. by reducing vaporized tetrachlorides in the presence of a diluent. Specified aluminium compounds are ethyloxy diethyl aluminium; octyloxy diethyl aluminium; mixtures of triethyl aluminium with octyloxy diethyl aluminium, octyloxy diethyl aluminium with dioctyloxy ethyl aluminium, triethyl aluminium with dioctyloxy ethyl aluminium, and triethyl aluminium with trioctyloxy aluminium. An example describes the copolymerization of ethylene and propylene in the presence of a catalyst comprising titanium trichloride, ethoxy diethyl aluminium, silica gel and sodium chloride.