摘要:
In catalyst systems of the Ziegler-Natta type modified during their preparation and comprising as active constituentsa) a titanium-containing solid component which is obtained by reacting a compound of titanium with a compound of magnesium, a halogen, an inorganic oxide as support, a C.sub.1 -C.sub.8 -alkanol and a carboxylic ester as electron donor compound,and also as cocatalystb) an aluminum compound andc) if desired, a further electron donor compound,the titanium-containing solid component a) is prepared by first, in a first stage, admixing an inorganic oxide as support with a solution of a chlorine-free compound of magnesium in an inert solvent, stirring this mixture for from 0.5 to 5 hours at from 10 to 120.degree. C. and subsequently reacting it while stirring continually in an inert solvent with a C.sub.1 -C.sub.8 -alkanol in an at least 1.3-fold excess, based on the compound of magnesium, to give a chlorine-free intermediate, then, without purification or extraction of the intermediate, adding a compound of trivalent or tetravalent titanium and a carboxylic ester as electron donor compound to this intermediate, stirring the resulting mixture for at least 30 minutes at from 20 to 130.degree. C., subsequently filtering off and washing the solid thus obtained and subsequently, in a second stage, extracting the solid obtained from the first stage in an inert solvent comprising at least 5% by weight of titanium tetrachloride and washing it with a liquid alkane.
摘要:
In catalyst systems of the Ziegler-Natta type comprising as active constituentsa) a titanium-containing solid component which is obtained by reacting a compound of titanium with a compound of magnesium, a halogen, an inorganic oxide as support, a C.sub.1 -C.sub.8 -alkanol and a carboxylic ester as electron donor compound,and also as cocatalyst,b) an aluminum compound andc) if desired, a further electron donor compound,the reaction of the individual components for preparing the titanium-containing solid component a) is carried out in the presence of an aromatic hydrocarbon as solvent.
摘要:
A process for the preparation of Ziegler-Natta type catalyst systems, containing, as active constituentsa) a titanium-containing solid component, which contains in addition to a compound of titanium at least one electron donor compound, and is present in an inert solvent in the form of a suspension, and, as co-catalyst,b) an aluminum compound andc) optionally further electron donor compoundsin which, following the preparation of the titanium-containing solid component a), the inert solvent present in the suspension is removed by first filtering the suspension in a first step, and then removing further solvent from the filtered material in a second step by applying a pressure difference at temperatures of not more than 100.degree. C.
摘要:
Catalyst systems of the type comprising the Ziegler-Natta catalysts contain, as active components,a) a titanium-containing solid component which contains titanium, magnesium, halogen and a carboxylic ester as an electron donor, and, as a cocatalyst,b) an aluminum compound andc) if required, a further electron donor, a compound of the following formula IR.sub.m.sbsb.1 Al--(OCOR.sup.1).sub.m.sbsb.2 (I)whereR and R.sup.1 are identical or different and are each hydrogen or C.sub.1 -C.sub.8 -alkyl andm.sub.1 and m.sub.2 are each 1 or 2 and sum to give 3, being used as aluminum compound b) in the preactivation of the titanium-containing soild compound a) with the cocatalyst.
摘要:
Process for polymerizing at least one olefinic monomer in a loop reactor at from 20 to 150° C., but below the melting point of the polymer to be formed, and a pressure of from 5 to 100 bar, where the polymer formed is present in a suspension in a liquid or supercritical suspension medium and this suspension is circulated by means of an axial pump, wherein the loop reactor comprises a cyclic reactor tube whose diameter varies by at least 10%, based on the predominant reactor tube diameter, and in which there is at least one widening and narrowing in a region other than that of the axial pump.
摘要:
Process for polymerizing at least one olefinic monomer selected from ethylene, propylene and 1-butene in a loop reactor in the presence of a polymerization catalyst at from 20 to 150° C., but below the melting point of a polymer to be formed, and a pressure of from 43 to 80 bar, where the polymer formed is present in a suspension in a liquid or supercritical suspension medium and wherein the suspension is circulated by means of an axial pump, wherein the polymerization is carried out at an average solids concentration in the reactor of more than 53% by weight, in the case of continuous product discharge, and at an average solids concentration in the reactor of more than 45% by weight, in the case of discontinuous product discharge, and wherein the polymerization is carried out at an ethylene concentration of at least 10 mol %, based on the suspension medium.
摘要:
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 R1, R2.x, R3.y which are connected in series and in which different reaction conditions are set. In this process, the offgases A1, A2.x, A3.y, A4 and A5 leaving all the reactors connected in series are firstly collected, the collected offgases are then compressed in a compression stage 10, 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.
摘要:
Catalyst for the polymerization and/or copolymerization of olefins which is obtainable by application to a finely divided inorganic support and concluding calcination at temperatures of from 350 to 1050° C. and has a chromium content of from 0.1 to 5% by weight and a zirconium content of from 0.5 to 10% by weight, in each case based on the element in the finished catalyst, with the molar ratio of zirconium to chromium being from 0.6 to 5.
摘要:
Process for preparing a supported catalyst for the polymerization and/or copolymerization of olefins which has a chromium content of from 0.01 to 5% by weight, based on the element, which comprises (a) preparing a homogeneous solution comprising an organic or inorganic chromium compound and at least one further organic or inorganic compound of elements selected from among Mg, Ca, Sr, B, Al, Si, P, Bi, Sc, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Ru, Rh, Pd, Hf, Ta, W in a protic or aprotic polar solvent, (b) bringing the solution from a) into contact with a finely divided inorganic support to form a catalyst precursor, (c) if appropriate, removing the solvent from the catalyst precursor and (d) calcining the catalyst precursor at temperatures of from 350 to 950° C., preferably 400 to 900° C., under oxidative conditions.
摘要:
A method for production of catalytic systems of the Ziegler-Natta type is characterised in comprising the following steps: A) bringing an inorganic metal oxide and a magnesium compound of formula MgRnX2-n into contact, where X=independently, fluorine, chlorine, bromine, iodine, hydrogen, NR2, OR, SR, SO3R or OC(O)R and R=independently, C1-C20 linear, branched, or cyclic alkyl, a C2-C10 alkenyl, an alkylaryl with 1-10 C atoms in the alkyl group and 6-20 C atoms in the aryl group, or a C6-C18 aryl and n=1 or 2, then, B) bringing the intermediate product obtained in step A) into contact with a halogenating reagent, C) bringing the intermediate product obtained in step B) into contact with a) a tetravalent titanium compound, b) a metallo-organic compound of group 3 of the periodic system and c) optionally, an electron-donor compound and D) washing the product obtained in step C) with an aprotic solvent. The invention further relates to a catalytic system obtained as above and a method for the polymerisation of olefins.