Abstract: Gas-phase fluidized-bed reactor for polymerizing ethylenically unsaturated monomers, comprising a reactor chamber (1) in the form of a vertical tube, if desired a calming zone (2) following the upper section of the reactor chamber, a circulation gas line (3), a circulation gas compressor (4) and a cooling device (5), where, in the region of transition of the reaction gas from the circulation gas line into the reactor chamber and in the lower section of the reactor chamber itself, there is either no gas distributor plate at all or only a gas distributor plate the total surface area of whose gas orifices is more than 20% of the total surface area of said gas distributor plate.

Abstract: Gas-phase fluidized-bed reactor for polymerizing ethylenically unsaturated monomers, comprising a reactor chamber (1) in the form of a vertical tube, if desired a calming zone (2) following the upper section of the reactor chamber, a circulation gas line (3), a circulation gas compressor (4) and a cooling device (5), where, in the region of transition of the reaction gas from the circulation gas line into the reactor chamber and in the lower section of the reactor chamber itself, there is either no gas distributor plate at all or only a gas distributor plate the total surface area of whose gas orifices is more than 20% of the total surface area of said gas distributor plate.

Abstract: Gas-phase fluidized-bed reactor for polymerizing ethylenically unsaturated monomers, comprising a reactor chamber (1) in the form of a vertical tube, if desired a calming zone (2) following the upper section of the reactor chamber, a circulation gas line (3), a circulation gas compressor (4) and a cooling device (5), where, in the region of transition of the reaction gas from the circulation gas line into the reactor chamber and in the lower section of the reactor chamber itself, there is either no gas distributor plate at all or only a gas distributor plate the total surface area of whose gas orifices is more than 20% of the total surface area of said gas distributor plate.

Abstract: A continuous vapor-phase fluidized-bed process for the preparation of ethylene homopolymers and copolymers having a density of from 0.87 to 0.97 g/cm3 in which ethylene or mixtures of ethylene and C3-C8 a-monoolefins are (co)polymerized in the presence of a supported chromium catalyst in the polymerization zone of a vapor-phase fluidized-bed reactor under pressures ranging from 1 to 100 bar and at temperatures ranging from 30° to 125° C. in the vapor phase in an agitated bed of bulk material comprising particulate polymer, the resultant heat of polymerization is removed by cooling the recirculated reactor gas and the resulting (co)polymer is removed from the vapor-phase fluidized-bed reactor, wherein, for the preparation of a (co)polymer of a specific density d, the (co)polymerization is carried out at a temperature which is in a range restricted by an upper envelope defined by equation I T H = 171 + 6 ? ? ? d ? 0.

Abstract: A continuous vapor-phase fluidized-bed process for the preparation of ethylene homopolymers and copolymers having a density of from 0.87 to 0.97 g/cm3 in which ethylene or mixtures of ethylene and C3-C8 a-monoolefins are (co)polymerized in the presence of a supported chromium catalyst in the polymerization zone of a vapor-phase fluidized-bed reactor under pressures ranging from 1 to 100 bar and at temperatures ranging from 30° to 125° C. in the vapor phase in an agitated bed of bulk material comprising particulate polymer, the resultant heat of polymerization is removed by cooling the recirculated reactor gas and the resulting (co)polymer is removed from the vapor-phase fluidized-bed reactor, wherein, for the preparation of a (co)polymer of a specific density d, the (co)polymerization is carried out at a temperature which is in a range restricted by an upper envelope defined by equation I 1 T H = 171 + 6 ⁢   ⁢ d ′ 0.

Abstract: A continuous vapor-phase fluidized-bed process for the preparation of ethylene homopolymers and copolymers having a density of from 0.87 to 0.97 g/cm3 in which ethylene or mixtures of ethylene and C3-C8 a-monoolefins are (co)polymerized in the presence of a supported chromium catalyst in the polymerization zone of a vapor-phase fluidized-bed reactor under pressures ranging from 1 to 100 bar and at temperatures ranging from 30° to 125° C.

Abstract: A process for preparing 1,2-diimine compounds of the formula I where R1 and R2 are, independently of one another, alkyl, aryl or metallocenyl radicals, and R3, R4 are, independently of one another, H, alkyl or aryl radicals or R3 and R4 are joined so as to form, with inclusion of the two imine carbon atoms, a 5- to 8-membered ring which may be saturated or unsaturated and may be unsubstituted or substituted by any hydrocarbon radicals. The process involves reacting 1,2-dicarbonyl compounds with primary amines, which have been activated with trialkylaluminum compounds prior to the reaction with the 1,2-dicarbonyl compounds. 1,2-Diimine compounds of the formula I in which R1 and R2 are, independently of one another, metallocenyl radicals can be used to prepare metal complexes which can be used as catalysts in a process for the polymerization of unsaturated compounds.

Abstract: A method for the treatment of catalyst or catalyst support material in an apparatus in which the treatment is carried out continuously in such a way that the physical and/or chemical conditions change during entry of the catalyst or catalyst support material into the apparatus and/or during exit thereof from the apparatus and/or the catalyst or catalyst support material is transported in the apparatus through zones (5, 6, 7) having different physical and/or chemical conditions.

Abstract: Polymers of propene consist of from 50 to 99.9% by weight of an isotactic propene copolymer (A′) and from 0.1 to 50% by weight of a propene homopolymer or a propene copolymer (B′), where a) the propene copolymer (A′) consists of from 80 to 99.9 mol % of propene and from 0.1 to 20 mol % of ethene and/or a C4-C12-1-olefin, at least 80% of all propene diads are isotactic meso diads, the propene copolymer (A′) has a proportion (XS) of material soluble in xylene at 20° C. which satisfies the inequality (1) (XS)<542 400 exp (−0.1TM)+0.5  (1),  the tensile modulus of elasticity (E) of the propene copolymer (A′) in MPa, determined in accordance with ISO 527, obeys the inequality (2) (E)>1.9×10−11(TM)6.34+180 MPa  (2),  where in both inequalities (1) and (2) TM is the melting point in ° C.

Abstract: In a continuous gas-phase polymerization process for preparing ethylene and propene homopolymers and copolymers, in which ethylene, propene or a mixture of ethylene or propene and C3-C8-&agr;-monoolefins is polymerized in the polymerization zone of a gas-phase polymerization reactor at from 30 to 125° C. and a pressure of from 1 to 100 bar in the gas phase in a bed of finely divided polymer in the presence of a catalyst, where the reactor gas is circulated to remove the heat of polymerization, polymer deposits in the circulating gas line are prevented by metering a catalyst poison having a boiling point above the maximum temperature within the circulating gas line into this circulating gas line in at most such an amount that it does not significantly impair the productivity of the catalyst in the reactor.

Abstract: Homopolymers of ethylene or copolymers of ethylene with other olefins or mixtures thereof are prepared by suspension polymerization in the presence of catalyst systems by a process in which the catalyst systems used are those which contain, as active components,A) a finely divided carrier treated with trialkylaluminum,B) a metallocene complex,C) an open-chain or cyclic alumoxane compound andD) an alkali metal alkyl or alkaline earth metal alkyl or a mixture thereof.