Abstract: A method for producing a welded joint is provided, including: providing an x-ray tube arranged within an x-ray housing for generating x-ray radiation and a detector arranged within a detector housing for receiving the x-ray radiation; flowing a cooling medium through the housing; heating components to be welded to the pre-heating temperature required for producing the welded joint; welding the welded joint; creating an exposure of the welded joint via the x-ray tubes and the detector at a temperature of the components which is essentially the pre-heating temperature or higher, wherein the cooling medium flows through the housing such that the x-ray tubes and the detector operate at the respective operating temperatures thereof.

Abstract: A method is disclosed for designing a local coil to be used in a combined PET magnetic resonance device for magnetic resonance imaging in relation to the arrangement of radiation-attenuating electronic elements in an irradiation area for PET photons. In an embodiment of the method, taking into consideration at least one boundary condition specifying the degree of freedom of the positioning of the electronic elements, optimization of the positions of the electronic elements is undertaken in an optimization method in respect of a uniform distribution of attenuation centers which is as substantial as possible.

Abstract: A C4-olefin mixture having a 1,3-butadiene content of from 100 to 500 ppm and a content of 1,2-dienes of less than 10 ppm is described. The present invention further provides a process for preparing this C4-olefin mixture and provides for its use in a metathesis reaction for preparing 2-pentene and/or 3-hexene.

Abstract: A C4-olefin mixture having a 1,3-butadiene content of from 100 to 500 ppm and a content of 1,2-dienes of less than 10 ppm is described. The present invention further provides a process for preparing this C4-olefin mixture and provides for its use in a metathesis reaction for preparing 2-pentene and/or 3-hexene.

Abstract: A C4-olefin mixture having a 1,3-butadiene content of from 100 to 500 ppm and a content of 1,2-dienes of less than 10 ppm is described. The present invention further provides a process for preparing this C4-olefin mixture and provides for its use in a metathesis reaction for preparing 2-pentene and/or 3-hexene.

Abstract: Processes for preparing a C5 aldehyde and propene are disclosed, the processes comprising: (a) providing a feedstream, the feedstream comprising butane, 1-butene, 2-butene and 1,3-butadiene, the 1,3-butadiene present in the feedstream in an amount up to 1000 ppm; (b) contacting the feedstream with hydrogen and carbon monoxide in the presence of a hydroformylation catalyst to form a 2-butene-rich butane stream and a C5 aldehyde; (c) separating the 2-butene-rich butane stream and the C5 aldehyde; and (d) contacting the 2-butene-rich butane stream with ethene in the presence of a metathesis catalyst to form a propene-containing hydrocarbon stream.

Abstract: Preparation of polyisobutylene having a content of terminal double bonds of more than 50% by polymerizing isobutene using a polymerization catalyst customary therefor from a technical 1-butene-, 2-butene- and isobutene-containing C4 hydrocarbon stream which may comprise up to 3000 ppm by weight, of 1,3-butadiene, by reducing the content of oxygenates in the C4 hydrocarbon stream before the polymerization of the isobutene by contacting it with an inorganic adsorbent at a pressure of from 1 to 20 bar and a temperature of from 20 to 220° C.

Abstract: The present invention provides a process for preparing a supported catalyst (catalyst C) having a support (support S) selected from among oxides, phosphates, silicates, carbides, borides and nitrides of main group elements and elements of transition groups VI and II and mixtures of the abovementioned compounds and an active component (activator A) comprising one or more compounds containing one or more elements of transition groups V, VI and VII customary for the catalysis of metathesis reactions.

Abstract: Process for preparing a stream consisting essentially of ethene (stream C2=), a stream consisting essentially of propene (stream C3=), a stream consisting essentially of isobutene and possibly other olefins having 4 carbon atoms (stream C4=) and a stream consisting essentially of 2-methyl-2-butene and possibly 2-butene (stream C5=), and, if appropriate, a stream which comprises other hydrocarbons (stream Cx) and may consist of a plurality of separate substreams, which comprises a metathesis step in which a C4-hydrocarbon stream comprising at least 15% by weight of 2-butenes, at least 5% by weight of isobutene and not more than 5% by weight of 1-butene (feed stream) is brought into contact with ethene in the presence of a customary metathesis catalyst and the resulting hydrocarbon stream is fractionated to give the streams C2=, C3=, C4= and, if appropriate, Cx and all or part of the stream C5= is recirculated to the metathesis step.

Abstract: Processes comprising: (a) providing a feed stream comprising a C4 compound having at least a nonaromatic C—C double bond or C—C triple bond; (b) contacting the feed stream with an adsorbent which has been activated at a temperature of 450 to 1000° C. comprising at least 3% by weight of aluminum oxide to remove one or more impurities from the feed stream; and (c) contacting the feed stream from which one or more impurities have been removed with a metathesis catalyst under metathesis reaction conditions to form a compound or a mixture of compounds having a nonaromatic C—C double bond or C—C triple bond.

Abstract: A C4-olefin mixture having a 1,3-butadiene content of from 100 to 500 ppm and a content of 1,2-dienes of less than 10 ppm is described. The present invention further provides a process for preparing this C4-olefin mixture and provides for its use in a metathesis reaction for preparing 2-pentene and/or 3-hexene.

Abstract: The present invention relates to a process for preparing polyol alkyl ethers by reacting compounds comprising at least three hydroxyl functionalities with olefins in the presence of acidic catalysts at temperatures of from 20 to 250° C. and pressures of from 0.5 to 10 bar, wherein the olefins correspond to the general formula (I) in which R1 is hydrogen and R2 is a linear or branched carbon radical having from 7 to 28 carbon atoms, or R1 and R2 are each linear or branched carbon radicals having from 1 to 27 carbon atoms, the sum of the carbon number of R1 and R2 being at most 28, to polyol alkyl ethers derived from compounds having at least three hydroxyl functionalities, not more than all but one hydroxyl functionality being replaced by a moiety of the general formula (VIII) to the use of these polyol alkyl ethers as surfactants and to laundry detergents and cleaning compositions comprising these polyol alkyl ethers.

Abstract: Process for producing a supported catalyst which comprises at least 75% by weight of Al2O3, whose proportion of Al2O3 in the delta or theta modification is, based on the proportion of Al2O3, at least 1% and which comprises a rhenium compound and, if appropriate, a promoter as active component (A), which comprises a) converting a customary support (S) which comprises at least 75% by weight of Al2O3 and to which a promoter may, if appropriate, have been applied is converted into a modified support (S) whose proportion of Al2O3 in the delta or theta modification is, based on the proportion of Al2O3, at least 1% by calcining the customary support (S) at a temperature of from 750 to 1100°C., b) producing a supported catalyst precursor from the modified support (S) by applying the active component (A) comprising the rhenium compound to the modified support (S) and c) calcining the supported catalyst precursor at a temperature of from 500 to 750° C.

Abstract: Processes for preparing a C5 aldehyde and propene are disclosed, the processes comprising: (a) providing a feedstream, the feedstream comprising butane, 1-butene, 2-butene and 1,3-butadiene, the 1,3-butadiene present in the feedstream in an amount up to 1000 ppm; (b) contacting the feedstream with hydrogen and carbon monoxide in the presence of a hydroformylation catalsyt to form a 2-butene-rich butane stream and a C5 aldehyde; (c) separating the 2-butene-rich butane stream and the C5 aldehyde; and (d) contacting the 2-butene-rich butane stream with ethene in the presence of a metathesis catalyst to form a propene-containing hydrocarbon stream.

Abstract: Supported catalyst comprising a support (S) in which Al2O3 is present in a proportion of at least 75% by weight and rhenium compounds as active component (A), wherein the maximum of the distribution function of the pore diameters in the mesopore range is at from 0.008 to 0.050 ?m.

Abstract: The preparation of alkylaryl compounds takes place by a) reaction of a C4/C5-olefin mixture over a metathesis catalyst to prepare a C4-8-olefin mixture comprising 2-pentene, and optional removal of the C4-8-olefin mixture, b) removal of from 5 to 100% of the 2-pentene present in stage a) and subsequent reaction over an isomerization catalyst to give a mixture of 2-pentene and 1-pentene which is returned to stage a), c) dimerization of the C4-8-olefin mixture obtained in stage b) following removal in the presence of a dimerization catalyst to give a mixture containing C8-16-olefins, removal of these C8-16-olefins and optional removal of a partial stream thereof, d) reaction of the c8-16-olefin mixtures obtained in stage c) or of the partial stream with an aromatic hydrocarbon in the presence of an alkylation catalyst to form alkyl aromatic compounds where, prior to the reaction, 0 to 60% by weight, based on the c8-16-olefin mixtures obtained in stage c), of linear olefins may additionally be added, e) opt

Abstract: The invention relates to a method for the production of 1,7 octadiene by reacting metathesis of cyclohexene with ethylene. The invention also relates to the production of 1,10-decandiol by hydroformulating 1,7 octadiene produced according to said method. The invention further relates to a method for the production of muscone or olefinically unsaturated analogs thereof using 1,10 decandiol which is obtainable in said manner.

Abstract: In a process for preparing alkylaryl compounds by reacting a C10-14-monoolefin mixture with an aromatic hydrocarbon in the presence of an alkylation catalyst to form alkyl aromatic compounds and if appropriate subsequently sulfonating and neutralizing the resulting alkylaryl compounds, in the C10-14-monoolefins, on average, more than 0% and up to 100% of methyl branches are present in the longest carbon chain and fewer than 50% of the methyl branches are in the 2-, 3- and 4-position, calculated starting from the chain ends of the longest carbon chain.

Abstract: The invention relates to a method for producing dialdehydes and/or ethylenically unsaturated monoaldehydes by reacting at least one compound with at least two ethylenically unsaturated double bonds with carbon monoxide and hydrogen in the presence of a hydroformylating catalyst with at least one complex of a metal of subgroup VIII. The subgroup comprises at least pnicogen chelate ligands.

Abstract: Method of regenerating an Re2O7-doped supported catalyst which has been deactivated by use in the metathesis of a hydrocarbon mixture comprising C2-C6-olefins (C2-6= feed) (deactivated catalyst), which comprises treating the deactivated catalyst with an inert gas (regeneration gas K1) at from 400 to 800° C. and subsequently treating the deactivated catalyst which has been pretreated with regeneration gas K1 with an oxygen-containing gas (regeneration gas K2).