Abstract: Organic polymer moldings with ion-exchanger properties or with adsorber properties are produced by means of a powder-based rapid-prototyping process in which a pulverulent organic polymer starting material or starting material mixture is applied in a thin layer to a substrate and then, at selected sites of this layer, is subjected to admixture of a binder and of any necessary auxiliaries, or is irradiated or otherwise treated, so that the powder becomes bonded at these sites, as a result of which the powder becomes bonded not only within the layer but also to the adjacent layers, and this procedure is repeated until the desired shape of the molding has been replicated completely in the resultant powder bed, and then the powder not bonded by the binder is removed, so that the bonded powder is retained in the desired shape, where the starting material itself has the ion-exchanger properties or adsorber properties, or appropriate functionalization of the molding takes place after the shaping process.

Abstract: Process for preparation of ethylene homopolymers or copolymers, comprising the steps of a) polymerization of ethylene or of ethylene with one or more other 1-olefins in the presence of a chromium catalyst at temperatures of from 20 to 200° C. and at pressures of from 0.1 to 20 MPa, where the chromium catalyst can be prepared via application of one or more chromium compounds to a silicate support and subsequent thermal activation under oxidative conditions at temperatures of from 620 to 900° C.; b) mixing of the polyethylene in the melt in the presence of from 1000 to 2000 ppm of an antioxidant comprising at least one sterically hindered phenol and comprising at least one phosphite in a mixing ratio of from 1:5 to 5:1, with specific energy input of at least 0.17 kWh/kg.

Abstract: A process for preparing supported, titanized chromium catalysts is disclosed. The process comprises A) bringing a support material into contact with a protic medium comprising a titanium compound and a chromium compound; B) optionally removing the solvent; C) optionally calcining the precatalyst obtained after step B); and D) optionally activating the precatalyst obtained after step B) or C) in an oxygen-containing atmosphere at from 400° C. to 1100° C.

Abstract: A process for preparing alkanols (I) selected from the group consisting of isopropanol and 2-butanol from the corresponding alkanes (II) selected from the group consisting of propane and n-butane, comprising the steps of: A) providing a starting gas stream a comprising the alkane (II); B) feeding the starting gas stream a comprising the alkane (II) into a dehydrogenation zone and subjecting the alkane (II) to a dehydrogenation to the alkene (III) to obtain a product gas stream b comprising the alkene (III) and unconverted alkane (II), with or without high boilers, steam, hydrogen and low boilers; C) at least compressing product gas stream b, optionally separating product gas stream b into an aqueous phase c1, a phase c2 comprising the alkene (III) and the alkane (II), with or without high boilers, and a gas phase c3 comprising hydrogen and low boilers; D) reacting product gas stream b or the phase c2 comprising alkene (III) and alkane (II) with an organic acid (IV) in an esterification zone to obtain a produ

Abstract: Method of determining the composition of polymer mixtures comprising defined polymer components of differing mean molar masses Mn, which comprises the steps (a) recording of at least one 1H-NMR relaxation curve of the polymer mixture and (b) calculating the proportions of the polymer components by matching the measured relaxation curve with the relaxation curves of the individual polymer components. In this way, the composition of polymer mixtures can be determined quickly and simply. Furthermore, process integration for regulating the polymerization is possible.

Abstract: A process is proposed for reprocessing the exhaust gas from a plant for producing hydroxylamine or hydroxylammonium salts by catalytic reduction of nitrogen monoxide with hydrogen for the purpose of utilization of at least a part of the nitrogen monoxide and if appropriate hydrogen present in the exhaust gas for producing hydroxylamine or hydroxylammonium salts, which comprises, in a first separation stage, selectively separating off nitrogen monoxide from the exhaust gas of the plant for producing hydroxylamine or hydroxylammonium salts.

Abstract: A process for preparing alkanols (I) selected from the group consisting of isopropanol and 2-butanol from the corresponding alkanes (II) selected from the group consisting of propane and n-butane, comprising the steps of: A) providing a starting gas stream a comprising the alkane (II); B) feeding the starting gas stream a comprising the alkane (II) into a dehydrogenation zone and subjecting the alkane (II) to a dehydrogenation to the alkene (III) to obtain a product gas stream b comprising the alkene (III) and unconverted alkane (II), with or without high boilers, steam, hydrogen and low boilers; C) at least compressing product gas stream b, optionally separating product gas stream b into an aqueous phase c1, a phase c2 comprising the alkene (III) and the alkane (II), with or without high boilers, and a gas phase c3 comprising hydrogen and low boilers; D) reacting product gas stream b or the phase c2 comprising alkene (III) and alkane (II) with an organic acid (IV) in an esterification zone to obtain a produ

Abstract: The invention relates to a device for partitioning the plastic parisons to give at least one semifinished open-surface product (6), where the device encompasses at least one means of partitioning (3) the plastic parison and one means of drive (2). The means of drive may be composed of one, but preferably of two, driven rolls. It has been found that use of the device of the invention can reduce or prevent the production of creasing and irregularity at the margins, i.e. at the cut edges, of the partitioned parisons, i.e. of the resultant semifinished sheets.

Abstract: In a method of selecting polymerization catalysts, in particular Phillips catalysts for the polymerization of olefins, from a multiplicity of catalysts on the basis of their catalytic properties, a multiplicity of catalyst precursors or catalyst supports are converted in parallel into polymerization catalysts in a pretreatment step in an array of reactors, where the pretreatment comprises at least one thermal treatment step at from 250 to 1200° C. Furthermore, at least one starting material is converted with the aid of the respective polymerization catalysts under prescribed polymerization conditions into at least one polymer product in a polymerization step and, finally, analysis of the polymer product or products is carried out to determine its composition and/or chosen properties. This makes it possible to carry out a thermal pretreatment of polymerization catalysts quickly under defined conditions which can be varied.

Abstract: 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 in the finished catalyst, is supported on a finely divided inorganic support and is obtainable by concluding calcination at temperatures of from 350 to 1050° C. and has a zinc content of from 0.01 to 10% by weight, based on the element in the finished catalyst.

Abstract: Method of determining the composition of polymer mixtures comprising defined polymer components of differing mean molar masses Mn, which comprises the steps (a) recording of at least one 1H-NMR relaxation curve of the polymer mixture and (b) calculating the proportions of the polymer components by matching the measured relaxation curve with the relaxation curves of the individual polymer components. In this way, the composition of polymer mixtures can be determined quickly and simply. Furthermore, process integration for regulating the polymerization is possible.

Abstract: When rolling sheets or strips in roll stands using working rolls, which are supported on back-up rolls or on intermediate rolls having back-up rolls, whereby the setting of the roll gap is effected by axially displacing roll pairs provided with curved contours, differences from the required profile occur in the instance of larger widths of a product range due to excessive extensions in the edge areas or in the quarter areas that are manifested in the form of so-called quarter waves in the flatness of the product.

Abstract: The invention relates to a process for preparing a supported catalyst, in particular for the polymerization and/or copolymerization of olefins, which comprises: a) preparing a hydrogel; b) milling the hydrogel to give a finely particulate hydrogel; c) producing a slurry based on the finely particulate hydrogel; d) drying the slurry comprising the finely particulate hydrogel to give the support for catalysts; e) producing the supported catalyst by applying at least one transition metal and/or at least one transition metal compound to the support for catalysts and, if appropriate, activating the applied metal and/or compound, wherein a finely particulate hydrogel in which at least 5% by volume of the particles, based on the total volume of the particles, have a particle size in the range from >0 ?m to ?3 ?m; and/or at least 40% by volume of the particles, based on the total volume of the particles, have a particle size in the range from >0 ?m to ?12 ?m, and/or at least 75% by volume of the particles, base

Abstract: The present invention relates to a multistage process for producing hollow plastic articles, encompassing the following steps: a) producing a tubular plastic parison by means of extrusion or coextrusion; b) cutting open the plastic parison to produce two planar-surface parts; c) molding the planar-surface parts in two mold halves to give half shells, where a removable intermediate frame separates the mold halves from one another at least along the peripheral edges, so that the semifinished products/half shells are not in contact with one another; d) opening the mold halves and removing the intermediate frame; e) closing the mold halves, with the result that the half shells come into contact with one another along a peripheral rim; and f) bonding the half shells to give a hollow article.

Abstract: The invention relates to a roll stand comprising a crown-variable-control (CVC) roll pair, preferably a CVC working roll pair and a back-up roll pair, which comprise a contact area (B cont) in which a horizontally active torque (M) acts that leads to a twisting of the rolls and thus to axial forces in the roll bearings. In order to keep the axial forces in the roll bearings as small as possible, the torque (M) is minimized by an appropriate CVC grinding.

Abstract: In a method of selecting polymerization catalysts, in particular Phillips catalysts for the polymerization of olefins, from a multiplicity of catalysts on the basis of their catalytic properties, a multiplicity of catalyst precursors or catalyst supports are converted in parallel into polymerization catalysts in a pretreatment step in an array of reactors, where the pretreatment comprises at least one thermal treatment step at from 250 to 1200° C. Furthermore, at least one starting material is converted with the aid of the respective polymerization catalysts under prescribed polymerization conditions into at least one polymer product in a polymerization step and, finally, analysis of the polymer product or products is carried out to determine its composition and/or chosen properties. This makes it possible to carry out a thermal pretreatment of polymerization catalysts quickly under defined conditions which can be varied.

Abstract: The invention relates to a device for partitioning the plastic parisons to give at least one semifinished open-surface product (6), where the device encompasses at least one means of partitioning (3) the plastic parison and one means of drive (2). The means of drive may be composed of one, but preferably of two, driven rolls. It has been found that use of the device of the invention can reduce or prevent the production of creasing and irregularity at the margins, i.e. at the cut edges, of the partitioned parisons, i.e. of the resultant semifinished sheets.

Abstract: Process for preparing supported, titanized chromium catalysts, which comprises the following steps: A) bringing a support material into contact with a protic medium comprising a titanium compound and a chromium compound, B) optionally removing the solvent, C) optionally calcining the precatalyst obtained after step B) and D) optionally activating the precatalyst obtained after step B) or C) in an oxygen-containing atmosphere at from 400° C. to 1100° C.

Abstract: A hollow plastic article is described, with at least one opening and with a structure which has one or more layers, the hollow plastic article comprising at least one layer made from a polyolefin which was prepared using a fluorine-modified chromium catalyst. The use of hollow plastic articles of the invention as plastic fuel containers, gasoline canisters, plastic tanks, or plastic bottles or the like is also described.

Abstract: The invention relates to a process for preparing a catalyst for the polymerization of olefins, which comprises: a) preparation of a finely divided silica xerogel, b) loading of the xerogel with chromium from a solution of chromium trioxide or a chromium compound which is converted into chromium trioxide under the conditions of step c), and c) activation of the resulting product at from 400 to 1100° C. in a water-free gas stream comprising oxygen in a concentration of above 10% by volume, wherein a fluoride doping with a fluorinating agent is carried out in step b) or in step c). Furthermore, the invention relates to a catalyst for the polymerization of olefins which is obtainable by the process of the invention and to a process for the polymerization of olefins in which an olefin or an olefin mixture is polymerized in the presence of a catalyst according to the invention.