摘要:
A process is disclosed for the selective catalytic hydrogenation of carbonyl groups in aromatic aldehydes of the formula: ##STR1## in which X is carboxyl, methyl or a halogen, to give the corresponding alcohols and methyl compounds. The catalytic hydrogenation is performed with the addition of a solvent optionally in the presence of organic acids on a shaped support catalyst containing a platinum group metal on a support made from titanium oxide in the presence of hydrogen at hydrogen partial pressures of 5 to 50 bar and temperatures of 100.degree. to 300.degree. C.
摘要:
A ternary platinum alloy catalyst on a conductive carbon carrier for use in fuel cells is disclosed. For the production of the catalyst, nitrate salts are used as precursors of the alloy components and all alloy components are deposited concurrently on the carbon carrier. This method of procedure yields ageing-stable catalysts with high oxygen mass activity.
摘要:
A process for the production of 1,3-propanediol by heterogeneously catalyzed hydrogenation of 3-hydroxypropionaldehyde in an aqueous solution at 30 to 180° C., at a hydrogenation pressure of 5 to 300 bar and a pH value of 2.5 to 7.0, wherein ruthenium on an oxide support is used as the catalyst.
摘要:
The use of modified silicon dioxide as a catalyst support in catalytic reactions under hydrothermal conditions is described. The pore structure of the supports may be stabilized against hydrothermal reaction conditions by impregnating the catalyst supports with elements of Group IVB of the Periodic Tube of Elements.
摘要:
In the heating device, PTC heating elements arranged between current rails lying opposite each other are used, which are fed with supply current from a control electronics unit via the current rails. Metallic heating rib structures are respectively coupled to one of the current rails via an electrically insulating but thermally conducting coupling layer. The air to be heated flows through the heating rib structures which have an undulating shape. The metallic heating rib structures are electrically connected to vehicle ground and thus form a shield that eliminates emissions of electromagnetic interfering radiation without impeding the flow of air.
摘要:
A collimator module is disclosed for the modular assembly of a collimator for a radiation detector with a multiplicity of absorber elements, which are arranged one behind the other in a collimation direction and held by a carrier. In at least one embodiment, the carrier has at least one alignment device for aligning the collimator module in the collimation direction, which alignment device(s) interact with positioning device(s) in a detector mechanism of the radiation detector when they are integrated into the radiation detector. This provides the preconditions for integrating the collimator module in a fashion that is decoupled from a radiation convertor, and so this allows easy assembly of a collimator and adjustment to a position assumed between a radiation convertor and the collimator. Moreover, a radiation detector with such a collimator module is disclosed.
摘要:
A collimator is disclosed. The ends of collimator plates are potted with the aid of a top plate and a bottom plate with the formation of interspaces, defined by spacings, between the collimator plates. When producing such a collimator, the top and bottom plates are produced using a casting method, and the collimator plates are simultaneously cast in, in order to fix them in the bottom and top plates. For this production method, a reusable holding apparatus that holds the collimator plates, and a casting mold are provided for aligning and positioning purposes.
摘要:
A radiation detector has a photodiode arrangement, a number of scintillators, and a reflector part having a number of compartments corresponding to the number of scintillators, which receive the scintillators in such a way that the scintillators are surrounded by walls of the compartments with the exception of their side respectively facing the photodiode arrangement.
摘要:
Raney copper which is doped with at least one metal from the group comprising iron and/or noble metals is used as a catalyst in the dehydrogenation of alcohols.
摘要:
Disclosed are shell catalysts which contain, on powdered or shaped supports, one or more metals from groups VIII and IB of the Periodic Table of Elements. The catalysts are obtained by coating the support with the catalytically active metals in aqueous solutions of mono- or bimetallic colloids of these metals, wherein the colloids are stabilized by highly hydrophilic surfactants.