Abstract: The present invention relates to a process for preparing oligomers consisting mainly of repeating units derived from 1- or 2-butene from a hydrocarbon stream consisting substantially of branched and linear hydrocarbon compounds having 4 carbon atoms, and comprising olefinic branched and linear hydrocarbon compounds having 4 carbon atoms (C4 starting stream) by a. in step a), separating the C4 starting stream into a fraction consisting mainly of linear hydrocarbon compounds having 4 carbon atoms (l-C4 fraction) and a fraction consisting mainly of branched hydrocarbon compounds having 4 carbon atoms (b-C4 fraction), by contacting the C4 starting stream with a membrane which is easier to pass for linear hydrocarbon compounds having 4 carbon atoms than for branched hydrocarbon compounds having 4 carbon atoms, b. in step b), optionally after removing butanes, oligomerizing the olefinic hydrocarbon compounds having 4 carbon atoms present in the l-C4 fraction, c.

Abstract: The invention relates to a fuel cell having a moderate operating temperature which comprises a cathode, an anode and an electrolyte, where at least the cathode comprises a material having the composition (Sr1-xCax)1-yAyMn1-zBzO3-? and A is at least one element from the group consisting of Ba, Pb, Na, K, Y and the lanthanide group, B is at least one element from the group consisting of Mg, Al, Ga, In, Sn and sub-group elements from the 4th, 5th or 6th period, and x adopts values of from 0.2 to 0.8, y adopts values of from 0 to 0.4, z adopts values of from 0 to <1, and ? adopts values which arise taking into account the electroneutrality principle.

Abstract: The present invention relates to a process and an apparatus for the deionization of a cooling medium of a fuel cell circulating in a cooling circuit. According to the invention, a liquid deionizing agent is allowed to act at least intermittently on the cooling medium so that the deionizing agent can take up ions from the cooling medium. For this purpose, the fuel cell apparatus (10) of the present invention, which comprises at least one fuel cell (11) and at least one cooling circuit (20) for the fuel cell, has at least one deionization apparatus (23) in which a liquid deionizing agent can act on the cooling medium in the cooling circuit (20). The deionization apparatus can comprise static mixers (28, 34) downstream of which membrane separators (29, 35) are installed.

Abstract: Reactor membranes for used in oxidation reactions of hydrocarbons involving oxygen comprising a selective oxidation catalyst on a mixed conducting, oxide ion selective ceramic membrane of the composition (Sr1-xCax)1-yAyMn1-zBzO3-&dgr;, where A is Ba, Pb, Na, K, Y, an element of the lanthanide group or a combination thereof, B is Mg, Al, Ga, In, Sn, an element of the 3d or 4d period or a combination thereof, x is from 0.2 to 0.8, y is from 0 to 0.4, z is from 0 to 0.6, and &dgr; is a number, dependent on x, y and z, that renders the composition charge neutral.

Abstract: The invention relates to an improved method for the production of D-pantothenic acid and/or salts thereof and use thereof as adjunct for animal feedstuffs.

Abstract: The invention relates to a fuel cell having a moderate operating temperature which comprises a cathode, an anode and an electrolyte, where at least the cathode comprises a material having the composition (Sr1-xCax)1-yAyMn1-zBzO3-&dgr; and

Abstract: Reactor membranes advantageously useful in oxidation reactions of hydrocarbons involving oxygen comprise a selective oxidation catalyst on a mixed conducting, oxide ion selective ceramic membrane of the composition (Sr1-xCax)1-yAyMn1-zBzO3-&dgr;, where

Abstract: The present invention relates to a method for the isolation of olefins from a gas mixture comprising one or more olefins, inert gas and catalyst poison, where the gas mixture is fed to a separation unit (18) and separated into olefin and inert gas. The method according to the invention has the special feature that an apparatus (17) is installed upstream or downstream of the separation unit (18) and that i) in the case of an upstream apparatus (17), the catalyst poison is at least partially removed from the gas mixture, and ii) in the case of a downstream apparatus (17), the catalyst poison is at least partially removed from the separated-off olefin. The olefins here are preferably isolated from a gas mixture formed as offgas in catalytic gas-phase polymerization for the preparation of polyolefins. The recovery of the olefins from the offgas is of economic importance.

Abstract: A process for isolating trioxane from an aqueous mixture which includes trioxane, water and formaldehyde, including removing trioxane from the mixture by pervaporation, and subjecting the mixture enriched in trioxane (permeate) to rectification to give trioxane and an azeotropic mixture of trioxane, water and formaldehyde.