Basell Polyolefine Gmbh

Frank Peter Alt

Ludwig Böhm

Kaspar Evertz

Joachim Berthold

Peter Kölle

Friedhelm Gundert

Paul Schöneborn

The invention relates to a continuous process for preparing polyolefins having a bimodal or multimodal molar mass distribution in suspension in at least two reactors R, R.x, R.y which are connected in series and in which different reaction conditions are set. In this process, the offgases A, A.x, A.y, Aand Aleaving all the reactors connected in series are firstly collected, the collected offgases are then compressed in a compression stage, the compressed offgases are subsequently cooled and the cooled material is separated into a gaseous fraction and a liquid fraction. The separated fractions are then recirculated to the polymerization process at different points. The process of the invention allows the total conversion of the polymerization, based on monomer and comonomer used, to be increased to a surprising extent.

Process for preparing polyolefins in suspension

The invention relates to a modified Ziegler catalyst for preparing a poly-1-olefin in suspension, in solution or in the gas phase, which catalyst comprises the reaction product of a magnesium alkoxide (component a) with a transition metal compound (component b) and an organometallic compound (component c) together with an additional component (d) comprising a compound of the chemical formulaM&#x2212;Rwhere M is an element of main group IV of the Periodic Table, R is halogen or an organic radical such as alkyl having from 1 to 10 carbon atoms, oxyalkyl having from 1 to 10 carbon atoms, cycloalkyl having from 4 to 8 carbon atoms in the ring and, if desired, from 1 to 6 substituents R' on the ring, aryl having from 6 to 10 carbon atoms in the aromatic and, if desired, from 1 to 6 substituents R&#x2032; on the aromatic, where R&#x2032; is a halogen or an alkyl radical having from 1 to 4 carbon atoms or an OH group or an NOgroup or an oxyalkyl radical having from 1 to 4 carbon atoms, and x is an integer from 1 to 4. The invention also relates to a process for preparing the Ziegler catalyst and to the homopolymerization or copolymerization of 1-olefins in its presence.

Modified Ziegler catalyst, process for preparing it and process for preparing poly-1-olefins in its presence

The invention relates to a method for producing a poly-1-olefin by polymerisation of a 1-olefin of the formula RCH&#x2550;CH, in which Ris hydrogen or an alkyl radical having from 1 to 10 carbon atoms, in suspension, in solution or in the gas phase, at a temperature of from 20 to 200&#xb0; C. and a pressure of from 0.5 to 50 bar, in the presence of a catalyst which consists of the product of the reaction of a magnesium alkoxide with a transition-metal compound (component a) and an organometallic compound (component b), whose component a has been produced by reacting a transition-metal compound of titanium, zirconium, vanadium or chromium with a gelatinous dispersion of the magnesium alkoxide in an inert hydrocarbon. In accordance with the invention, the gelatinous dispersion is obtained by stirring using a stirring element, or shearing using a high-performance shearing tool, a suspension of magnesium alkoxide powder having a mean particle size, expressed as the dvalue, of less than 15 &#x3bc;m, obtained by dry-grinding of commercially available magnesium alkoxide powder having a mean particle size, expressed as the dvalue, of greater than or equal to 15 &#x3bc;m, preferably in the range from 100 to 1000 &#x3bc;m, in an inertized mill, in an aliphatic hydrocarbon in which the magnesium alkoxide particles are insoluble. The invention also relates to a catalyst which is suitable for carrying out the method.

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Frankfurt-am-Main, Germany

Frank Peter Alt