Abstract: The invention relates to an electrochemical cell comprising an anode and a cathode compartment separated by a membrane, housing corresponding electrodes. The anode and the cathode compartments having external walls with frame-type flanged areas in the contact area of both compartments. The flanged areas having mounting bores marking an inner area and an outer area of the electrochemical cell a, gas-diffusion electrode resting on a support system, a porous material resting on the gas-diffusion electrode, and devices for the inlet and outlet of gas and electrolyte. At least one circumferential gasket frame is in the contact area of both compartments, between the frame-type flanged areas of the external walls of both compartments, said gasket resting on the membrane, with the porous material and the gas-diffusion electrode resting on the frame-type cathodic flanged area and the circumferential gasket frame overlapping in this area with the porous material and the gas-diffusion electrode.

Abstract: Electrolyser comprising at least one single electrolyser element which comprises at least one anode compartment with an anode, one cathode compartment with a cathode and one ion exchange membrane arranged between the anode and the cathode compartments, with the anode and/or cathode being a gas diffusion electrode. A gap is provided between the gas diffusion electrode and the ion exchange membrane, with an electrolyte inlet arranged at the upper end of the gap and an electrolyte outlet at the lower end of the gap and a gas inlet and a gas outlet. The electrolyte outlet extending into a discharge header, and the electrolyte inlet connected to an electrolyte feed tank and having an overflow, the overflow connected to the discharge header, with a coiled hose connecting the electrolyte feed tank with the electrolyte inlet and with a coiled hose connecting the overflow with the discharge header.

Abstract: An oscillator with adjustable oscillation frequency includes an active device showing a negative input resistance at a terminal, an oscillator circuit coupled to the terminal of the active device showing the negative input resistance, and an element with adjustable ohmic resistance by which the oscillation frequency of the oscillator is adjustable.

Abstract: Processes for electrolysis of alkali metal chlorides with oxygen-consuming electrodes having startup and shutdown conditions which prevent damage to the constituents of the electrolysis cell.

Abstract: The invention relates to a process for production of diaryl carbonate combined with the electrolysis of the resultant alkali metal chloride-containing process wastewater. The process according to the invention makes possible, inter alia, improved utilization in electrolysis of the alkali metal chloride-containing solution obtained in the production of diaryl carbonate.

Abstract: A damping element implemented for damping a vibration transmitted between an injection valve and a cylinder head of an internal combustion engine may include a base body substantially shaped as a ring washer and at least one first contact segment fixedly coupled to the base body and protruding past the base body in a first axial direction and a second contact segment fixedly coupled to the base body and protruding past the base body in a second axial direction opposite the first axial direction. The first at least one contact segment has a radial offset from the longitudinal axis that is unequal to a radial offset of the second contact segment from the longitudinal axis.

Abstract: A method for controlling a valve including a spring, an actuator having an actuator force opposing the spring, and a pin actuatable by the actuator. To open the valve, in a first operating mode a current having a predefined curve is applied to the actuator, starting from a starting value of the current at which the pin is positioned to allow the valve to close, measured values of the current are determined chronologically sequentially, a reference value of the current takes on the current measured value of the current when the measured current deviates from the applied current by a predefined degree. In a second operating mode, a current having a predefined curve is applied to the actuator, starting with the starting value of the current to a final value of the current at which the pin is in a position that prevents the valve from closing.

Abstract: The present invention relates to an electrode that includes an electrically conducting substrate based on a valve metal having a main proportion of titanium, tantalum or niobium, and an electrocatalytically active coating comprising up to 50 mol % of a noble metal oxide or noble metal oxide mixture and at least 50 mol % of titanium oxide. The coating includes a minimum proportion of oxides of anatase structure determined by a ratio of the signal height of the most intensive anatase reflection in an x-ray diffractogram (CuK? radiation) after subtraction of a linear background to the signal height of the most intensive rutile reflection in the same diffractogram, wherein the ratio is at least 0.6.

Abstract: An oxygen-consuming electrode is described, more particularly for use in chloralkali electrolysis, comprising a novel catalyst coating based on silver and a finely divided silver oxide, as is an electrolysis apparatus. Also described is a production process for the oxygen-consuming electrode and the use thereof in chloralkali electrolysis or fuel cell technology.

Abstract: The invention relates to a method for improving the performance of nickel electrodes in alkali chloride electrolysis by adding water-soluble platinum compounds to the catolyte.

Abstract: The invention relates to a process for preparing methylenediphenyl diisocyanates which comprises at least the steps: A) reaction of aniline with formaldehyde in the presence of hydrochloric acid as catalyst to give a mixture of diamines and polyamines of the diphenylmethane series (MDA) and subsequent at least partial neutralization of the hydrochloric acid by means of alkali metal hydroxide, B) reaction of the mixture of diamines and polyamines of the diphenylmethane series obtained in step A) with phosgene to give a mixture of diisocyanates and polyisocyanates of the diphenylmethane series (MDI) and hydrogen chloride, wherein C) the hydrochloric acid which has been neutralized in step A) is separated off in the form of a solution containing alkali metal chloride and is subsequently at least partly fed to an electrochemical oxidation to form chlorine, alkali metal hydroxide and optionally hydrogen and D) at least part of the chlorine produced in step C) is used for preparing the phosgene used in step B).

Abstract: A process is described for the production of graphite electrodes coated predominantly with noble metal for electrolytic processes, especially for the electrolysis of hydrochloric acid, wherein the surface of a graphite electrode is coated with an aqueous solution of a noble metal compound and then tempered at 150 to 650° C. in the presence of reducing and/or extensively oxygen-free gases.

Abstract: A method for the installation of oxygen-consuming electrodes in electrochemical cells includes sealing one or more oxygen-consuming electrodes in an electrochemical half cell having damaged regions and/or overlap regions and applying a sealing paste. The sealing paste includes silver oxide, a hydrophobic polymer component, and a perfluorinated or partially fluorinated solvent. The method may be used, in particular, for chloralkali electrolysis. An electrochemical cell, having one or more adjoining oxygen-consuming electrodes with damaged and/or overlap regions sealed with a sealing paste having silver oxide, a hydrophobic polymer component, and a fluorinated solvent, is also disclosed.

Abstract: Methods for the reductive post-treatment of NaCl-containing solutions, wherein such methods comprise: providing a NaCl-containing solution obtained from an anode side of an NaCl electrolysis cell, the solution comprising reducible components; and subjecting the solution to cathodic electrochemical reduction.

Abstract: A combined process for the preparation of polycarbonate from bisphenols and diaryl carbonates, the monophenol liberated being reacted again for the preparation of the diaryl carbonate and the alkali metal halide forming in the preparation of the diaryl carbonate being converted by electrochemical oxidation, optionally over a gas diffusion electrode, into chlorine and alkali hydroxide solution, the chlorine being recycled into the preparation of the phosgene and the alkali hydroxide solution being recycled into the preparation of the diaryl carbonate.

Abstract: The present invention relates to an electrode comprising an electrically conductive substrate and a catalytically active layer, wherein the catalytically active layer is based on two catalytically active components and comprises iridium, ruthenium or titanium as metal oxide or mixed oxide or mixtures of the oxides, wherein the total content of ruthenium and/or iridium based on the sum of the elements iridium, ruthenium and titanium is at least 10 mol %, and wherein the electrode comprises at least one oxidic base layer which is applied to the electrically conductive substrate and is impermeable to aqueous electrolytes comprising NaCl and/or NaOH and/or HCl.

Abstract: An isocyanate is produced by: (a) reacting chlorine with carbon monoxide to form phosgene, (b) reacting the phosgene with an organic amine to form an isocyanate and hydrogen chloride, (c) separating the isocyanate and hydrogen chloride, (d) optionally, purifying the hydrogen chloride, (e) preparing an aqueous solution of the hydrogen chloride, (f) optionally, purifying the aqueous solution of hydrogen chloride, (g) subjecting the aqueous hydrogen chloride solution to electrochemical oxidation to form chlorine, and (h) returning at least a portion of the chlorine produced in (g) to (a).

Abstract: The present invention relates to A process for producing a transport- and storage-stable sheet-like oxygen-consuming electrode comprising providing an electrically conductive support, a gas diffusion layer, and a layer comprising a silver-based catalyst; coating the support with a silver oxide-containing intermediate; and at least partly electrochemically reducing the silver oxide-containing intermediate in an aqueous electrolyte at a pH of less than 8.

Abstract: An oscillator with adjustable oscillation frequency includes an active device showing a negative input resistance at a terminal, an oscillator circuit coupled to the terminal of the active device showing the negative input resistance, and an element with adjustable ohmic resistance by which the oscillation frequency of the oscillator is adjustable.

Abstract: A process is described for producing polycarbonate and utilizing at least some of the process waste water by concentrating the sodium chloride-containing waste water phases for the electrolysis using osmotic membrane distillation, if appropriate with simultaneous dilution of the sodium hydroxide solution obtained from the electrolysis for the polycarbonate production process.