Abstract: In a process for preparing at least one partial oxidation and/or ammoxidation product of propylene, the propylene is obtained from crude propane by dehydrogenating and subjected in the presence of unconverted propane as a constituent of a gas mixture 2 which comprises a total C4-hydrocarbon content of ?3% by volume to a heterogeneously catalyzed gas phase partial oxidation and/or partial gas phase ammoxidation.

Abstract: A process for continuous heterogeneously catalyzed partial dehydrogenation of at least one hydrocarbon to be dehydrogenated in a reactor which is manufactured from a composite material which consists, on its side in contact with the reaction chamber, of a steel B with specific elemental composition which, on its side facing away from the reaction chamber, either directly or via an intermediate layer of copper, or of nickel, or of copper and nickel, is plated onto a steel A with specific elemental composition, and also partial oxidations of the dehydrogenated hydrocarbon and the reactor itself.

Abstract: A process for preparing acrolein or acrylic acid or a mixture thereof as the target product from propane, in which propane is partially dehydrogenated under heterogeneous catalysis in a reaction zone A, molecular hydrogen formed is at least partly combusted to water, any water present in the product gas A formed in reaction zone A is removed therefrom and product gas A is otherwise used to charge a reaction zone B in which propylene formed in reaction zone A is partially oxidized in the presence of remaining propane to give the target product. The target product is removed from the product gas B formed in reaction zone B and propane present in the remaining residual gas is absorbed therefrom into a solvent and, after release from the absorbate, recycled into reaction zone A.

Abstract: A porous polymeric membrane formed from a blend of a polymeric membrane forming material, such as polyvinylidene fluoride or polysulfone and a polymeric reactivity modifying agent adapted to modify the surface active properties of the porous polymeric membrane. The reactivity modifying agent is preferably a linear polymeric anhydride, such as poly(alkyl vinyl ether/maleic anhydride). The surface activity modifications include modification of the hydrophilicity/hydrophobicity balance of the membrane, or hydrolysis followed by reaction with a polyamine to form a crosslinked polyamide layer. Such modified membranes have use as reverse osmosis membranes.

Abstract: The invention relates to a servo drive comprising an electromechanical energy converter, which has a rotatably mounted disc rotor for generating a torque and a stepping up mechanism that is connected downstream of the disc rotor, for coupling the disc rotor to an output element and for stepping up the torque that acts on the disc rotor and comprising a locking mechanism that locks a rotational displacement of the output element, when a torque is introduced on the output side. According to the invention, the locking mechanism comprises a coil spring which can be radially expanded and compressed and which extends around the outer periphery of the stepping up mechanism.

Abstract: Porous polymeric membranes including HALAR® (poly(ethylene chlorotrifluoroethylene)) and related compounds and the methods of production thereof which avoid the use of toxic solvents. Preferred solvents, coating agents and pore forming agents are citric acid ethyl ester or glycerol triacetate. The membranes may be in the form of a hollow fibre or flat sheet, and may include other agents to modify the properties of the membranes, such as the hydrophilic/hydrophilic balance. Leachable agents may also be incorporated into the membranes.

Abstract: A method for cleaning a microfiltration or ultrafiltration membrane comprising the step of contacting said membrane with a hydroxyl radical. The method is particularly suited for oxidation resistant membranes, such as Halar, with biological or organic fouling. The hydroxyl radicals for example are generated from an aqueous solution of transition metal ions, such as molybdenum, chromium, cobalt, copper, tungsten or more particularly iron, in conjunction with hydrogen peroxide under acidic conditions. The method is particularly suited to hollow fibre membranes where oxygen bubo es foamed in the course of the reaction create a flow that draws more liquid in through a wall of a vertical hollow fibre membrane and pushes water out of the top of the lumen, and where oxygen bubbles act to self agitate the solution which can break up a filter cake, where present, on the microfiltration or ultrafiltration membrane surface.

Abstract: Porous polymeric membranes including Halar (poly (ethylene chlorotrifluoroethylene)) and related compounds and the methods of production thereof which avoid the use of toxic solvents. Preferred solvents, coating agents and pore forming agents are citric acid ethyl ester or glycerol triacetate. The membranes may be in the form of a hollow fiber or flat sheet, and may include other agents to modify the properties of the membrane, such as the hydrophilic/hydrophobic balance. Leachable agents may also be incorporated into the membranes.

Abstract: A process for the long-term operation of a heterogeneously catalyzed partial gas phase oxidation of an organic starting compound, in which the reaction gas input mixture is partially oxidized over a fixed catalyst bed which is accommodated in two successive temperature zones A, B whose temperature is changed with increasing operating time such that the initially lower temperature increases and the difference between the two temperatures decreases.

Abstract: Porous polymeric membranes formed from a hydrophobic polymer, such as halar having membrane pores of a size sufficient to permit gas and/or vapor permeation 0.05 ?m to 5 ?m without permitting the flow of a hydrophilic fluid across the membrane. Pore distribution is uniform and porosity is high, in some cases up to 80%. Membranes may be in the form of a flay sheet or hollow fibre for example and can be used in a variety of applications such as stripping HF gas, degassing of caustic solution, chlorine gas/alkaline filtration, degassing tap water to remove dissolved chlorine. Processes used to make such membranes can be carried out using relatively non toxic solvents such as citric acid ethyl ester or glycerol triacetate.

Abstract: A process for heterogeneously catalyzed gas phase partial oxidation of an organic starting compound over a fixed catalyst bed freshly installed into a reaction chamber, in which the reduction in the quality of the fixed catalyst bed is restored with increasing operating time by replacing a portion of the fixed catalyst bed by a replacement fixed catalyst bed part whose volume-specific activity is lower than the volume-specific activity of the replaced fixed catalyst bed part in its freshly installed state.

Abstract: Process for preparing at least one partial oxidation and/or ammoxidation product of propylene, in which the propylene is produced from crude propane by dehydrogenation and is subjected to a heterogeneously catalyzed gas-phase partial oxidation and/or partial gas-phase ammoxidation in the presence of unreacted propane as constituent of a gas mixture 2 containing <1% by volume of 1-butene.

Abstract: A process for heterogeneously catalyzed partial gas phase oxidation of propylene to acrylic acid in the absence of propane as an inert diluent gas, in which, in the starting reaction gas mixture, cyclopropane is substantially avoided as an impurity and crude propylene is used additionally as a propylene source.

Abstract: The invention relates to a terpolymer of tetrafluoroethylene (TFE) monomer, polyvinylidene fluoride (PVDF) monomer and hexafluoropropylene (HFP) monomer for forming an ultrafiltration or microfiltration membrane, method of forming said membranes, and to the ultrafiltration or microfiltration membranes themselves. The invention also relates to a method of forming a polymeric ultrafiltration or microfiltration membrane including preparing a leachant resistant membrane dope which incorporates a leachable pore forming agent, casting a membrane from the dope and leaching the pore forming agent from the membrane. The invention also relates to a method of preparing a polymeric ultrafiltration or microfiltration membrane of improved structure including the step of adding a nucleating agent to the membrane dope before casting.

Abstract: Process for operating a continuous heterogeneously catalyzed gas phase partial oxidation of at least one organic compound using compressed air as the oxygen source which is filtered before its compression.

Abstract: In a friction pairing for clutch systems of two materials and processes for producing the pairing, one of the materials is a fiber-reinforced ceramic or metallic material A reinforced by carbon or ceramic fibers or whiskers. Material B acting against the material A in the friction pairing is selected from the group consisting of ceramic materials B11 and metallic materials B12, sintered metals B2, sintered oxidic ceramics B3, sintered nitridic ceramics B4, sintered carbidic ceramics B5 and organic sintered materials B6.

Abstract: In order to provide an insulating component (1) for the purpose of holding or guiding through an electrical conductor in switchgear assemblies in medium-voltage technology, the insulating component (1) having a nonconductive, rigid insulating body (3) having rigid outer ribs (6) for the purpose of extending the leakage path, which is also suitable for an application outdoors and is likewise cost-effective, it is proposed to apply an outer layer (7) made of oliophobic and/or hydrophobic material.

Abstract: A process for the heterogeneously catalyzed gas-phase partial oxidation of an organic compound over a fixed catalyst bed present in a fixed-bed reactor having a plurality of catalyst tubes, in which the reduction of the quality of the catalyst load with increasing duration of operation is restored by a partial catalyst change, is described.

Abstract: In a process for the purification of a crude acrylic acid melt, the crude acrylic acid melt is converted, under the action of low temperatures, into a crude acrylic acid suspension consisting of acrylic acid crystals and residual melt, and the acrylic acid crystals of the crude acrylic acid suspension are freed from remaining residual melt in a wash column, the production of the acrylic acid crystals of the crude acrylic acid suspension being carried out in the presence of water, the wash column being a wash column with forced transport of the acrylic acid crystals and the wash liquid used being the melt of acrylic acid crystals purified in the wash column.

Abstract: In a process for the heterogeneously catalyzed dehydrogenation in one or more reaction zones of one or more dehydrogenatable C2-C30-hydrocarbons in a reaction gas mixture comprising them, with at least part of the heat of dehydrogenation required being generated directly in the reaction gas mixture in at least one reaction zone by combustion of hydrogen, the hydrocarbon or hydrocarbons and/or carbon in the presence of an oxygen-containing gas, the reaction gas mixture comprising the dehydrogenatable hydrocarbon or hydrocarbons is brought into contact with a Lewis-acid dehydrogenation catalyst which has essentially no Brönsted acidity.