Abstract: An apparatus for carrying out polymerizations from the gas phase comprising a sealable reactor with a spiral stirrer which is rotatable in the reactor about a vertical axis to generate circulatory streams of the materials employed, in which the stirrer rotating within the reactor is surmounted by a stirrer rod, which extends upward beyond the uppermost flight circle of the stirrer and is attached to the stirrer at a certain distance from the axis of the stirrer, the distance of the side face of the stirrer rod from the reactor wall is at least 10 mm, and the surface of revolution of the moving rod matches the contour of the reactor in this zone.

Abstract: A process for the manufacture of thermoplastics fibrids, in which a solution of the thermoplastics material is fed to an impulse exchange chamber, where it is cooled so as to cause precipitation of the thermoplastics material, while it is subjected to a field of turbulent shear forces caused by the introduction of a gaseous or liquid medium into the said impulse exchange chamber.

Abstract: Manufacture of polymers of .alpha.-monoolefins by polymerization with a Ziegler catalyst system comprising (1) a catalyst component containing titanium and/or vanadium and (2) a particular compound of the metals aluminum, magnesium or zinc. The characteristic feature of the process according to the invention is that the catalyst component (1) containing titanium and/or vanadium is the solid-phase product (VII) contained by first (1.1) bringing a finely divided porous inorganic oxidic material (I), which has the formula Al.sub.2 O.sub.3 or SiO.sub.2.aAl.sub.2 O.sub.3, where a is a number from 0 to 2, into contact with an aluminum compound (II) dissolved in an organic solvent, to form a solid-phase product (III), then (1.2) bringing the solid-phase product (III) obtained in stage (1.1) into contact with a magnesium compound (IV), dissolved in an organic solvent, to form a solid-phase product (V), and finally (1.3) bringing the solid-phase product (V) obtained in stage (1.

Abstract: A process for the manufacture of olefin polymers by polymerizing .alpha.-monoolefins at relatively low temperatures and relatively low olefin pressures by means of a catalyst obtained from a silicate carrier (component a), an aluminum compound (component b) and a chromium compound (component c). The catalyst is obtained by (1) in a first stage, initially (1.1) charging a particular silicate carrier (component a) with (1.2) a mixture of (1.2.1) an aluminum salt or a mixture of an aluminum salt with up to 80 mole%, based on the salt mixture, of a nickel-II salt (component b) and (1.2.2) a chromium compound (component c), this compound being chromium trioxide or a compound which is converted to chromium trioxide under the conditions of stage (2), by treatment with a solution of the mixture (1.2), and (2), in a second stage then maintaining the product, obtained from stage (1), for a certain time at a high temperature in an anhydrous oxygen-containing gas stream.

Abstract: A process for the manufacture of homopolymers and copolymers of .alpha.-monoolefins of 2 to 6 carbon atoms by polymerizing the monomer or monomers by means of a Ziegler catalyst system comprising (1) a catalyst component containing titanium and (2) a particular compound of aluminum, magnesium or zinc, the atomic ratio of titanium from catalyst component (1) to metal (Me) from catalyst component (2) being from 1 : 0.1 to 1 : 500, wherein the titanium-containing catalyst component (1) employed is the solid-phase product (VI) obtained by (1.1) first bringing into contact (1.1.1) a particular finely divided, porous, inorganic oxidic material (I) and (1.1.2) a particular aluminum compound (II) dissolved in an organic solvent, to form a solid-phase product (III) and (1.2) then bringing into contact (1.2.1) the solid-phase product (III) obtained from stage (1.1) and (1.2.2) a solution (IV) which is obtained on bringing together (IVa) 100 parts by weight of a particular alcohol, (IVb) from 0.

Abstract: A process for the manufacture of olefin polymers by polymerizing .alpha.-monoolefins of 2 to 8 carbon atoms by means of a catalyst which is obtained from a silicate carrier (component a), an organo-metallic compound containing alkoxide groups (component b) and a chromium compound (component c), wherein the catalyst employed is obtained by (1) first charging (1.1) a finely divided porous xerogel (component a) of the formula SiO.sub.2 . m Al.sub.2 O.sub.3, where m is a number from 0 to 2, with (1.2) a particular aluminum compound containing alkoxide groups (component b), (2) then charging (2.1) the product obtained from stage (1) with (2.2) a particular chromium compound (component c) by treatment with a solution of the chromium compound, with intimate mixing and evaporation of the solvent and (3) finally heating the product, obtained from stage (2), in an anhydrous stream of gas containing oxygen.

Abstract: A process for the manufacture of homopolymers and copolymers of .alpha.-monoolefins of 2 to 6 carbon atoms by polymerizing the monomer or monomers by means of a Ziegler catalyst system comprising (1) a catalyst component containing titanium and (2) a particular compound of the metals aluminum, magnesium or zinc, the atomic ratio of titanium from catalyst component (1) to metal from catalyst component (2) being from 1:0.1 to 1:500, wherein the titanium-containing catalyst component (1) employed is the solid-phase product (IV) obtained by bringing into contact (1.1) a finely divided, porous, inorganic oxidic material (I) which has the formula SiO.sub.2 . aAl.sub.2 O.sub.3 --, where a is a number from 0 to 2, and (1.2) a solution (II) formed on bringing together (IIa) 100 parts by weight of an alcohol of the general formula Z--OH, where Z is a saturated hydrocarbon radical of 1 to 8 carbon atoms, (IIb) from 0.01 to 6 parts by weight (calculated as titanium) of a titanium trihalide and (IIc) from 0.

Abstract: A process for the manufacture of olefin polymers by polymerizing .alpha.-monoolefins of 2 to 8 carbon atoms by means of a catalyst which is obtained from a silicon-containing material (component a), an organo-metallic compound containing alkyl groups (component b) and a chromium compound (component c), wherein the catalyst employed is obtained by (1) first bringing into contact (1.1) an alkogel (component a) of the empirical formula SiO.sub.2 .multidot. m Al.sub.2 O.sub.3 .multidot. n ROH, where m is a number from 0 to 2, n is a number such that the content of ROH in the alkogel is from 1 to 85 per cent by weight and R is alkyl of 3 to 8 carbon atoms, and (1.2) an aluminum compound containing certain alkyl groups (component b), with intimate mixing, to form a solid-phase reaction product, (2) then bringing into contact (2.1) the solid-phase reaction product obtained from stage (1) and (2.

Abstract: A process for the manufacture of olefin polymers by polymerization of monoolefins using a silicic xerogel/chromium trioxide catalyst obtained by (1) synthesizing a particulate silicic xerogel, (2) doping said xerogel with chromium trioxide or a chromium compound capable of converting to chromium trioxide under the conditions of stage (3) and (3) heating the resulting product in a gas stream containing oxygen. The silicic xerogel/chromium trioxide catalyst used is one which has been obtained by (1) synthesizing the silicic xerogel in the first stage by (1.1) starting with a silicic hydrogel having a relatively high solids content, (1.2) extracting water from said hydrogel by means of an alkanol and/or alkanone until the organic liquid absorbs no further water, (1.3) extracting the organic liquid used in stage (1.

Abstract: This invention relates to a process for the manufacture of olefin polymers by polymerization of monoolefins with the aid of a silicic xerogel/chromium trioxide catalyst obtained by (1) synthesizing a particulate silicic xerogel, (2) doping this xerogel with chromium trioxide or a chromium compound which converts to chromium trioxide under conditions of stage (3) and (3) maintaining the resulting product at an elevated temperature in a water-free oxygen-containing stream of gas. The characteristic feature of the process of the invention is that the silicic xerogel/chromium trioxide catalyst used is one obtained by (1) synthesizing the silicic xerogel in the first stage as follows: (1.1) taking an aqueous solution of a sodium silicate, (1.2) substituting substantially all of the sodium ions contained in said solution by hydrogen ions by means of an ion exchanger, (1.3) introducing a water-soluble aluminum salt into the resulting aqueous silicic acid solution, (1.

Abstract: A process for the manufacture of olefin polymers by polymerization of .alpha.-monoolefins by means of a silicic acid xerogel/chromium trioxide catalyst, which is obtained by a method wherein (1) a finely divided silicic acid xerogel is first manufactured by (1.1) employing a silicic acid hydrogel of relatively high solids content, (1.2) extracting at least 60% of the water contained in the hydrogel from the latter by means of a particular organic liquid, (1.3) drying the gel thus obtained until there is no further loss in weight (xerogel formation) and (1.4) reducing the xerogel thus obtained to particles of diameter from 20 to 2,000 .mu.m,2. this xerogel is then charged with the desired amount of chromium from a solution of chromium trioxide or a solution of a chromium compound which under the conditions of stage (3) is converted to chromium trioxide, with evaporation of the solvent, and3. finally the product thus obtained is heated in an anhydrous stream of gas containing oxygen.

Abstract: Particulate olefin polymers are prepared by catalytic polymerization of monoolefins in an auxiliary liquid containing the monomers to be polymerized in dissolved form and the particulate polymer product in suspended form. The reaction mixture is recycled in a loop to which the starting materials are fed and from which the particulate polymer formed is removed. The essential features are (a) that a side stream is branched off from the loop, (b) that the side stream is caused to pass through a separating zone in which particulate olefin polymer is separated by centrifugal acceleration at temperatures and pressures in the same range as present in the loop and (c) that the separated particulate olefin polymer is discharged through flashing means.