Abstract: A catalytic process for preparing chlorine from hydrogen chloride, which includes recycle of process streams with reduced accumulation of inert gases in the system is provided. The process includes a step wherein a compressed liquid stream comprising chlorine, carbon dioxide and oxygen is recycled into a column countercurrent to the ascending gas phase and feeding part of the chlorine-rich liquid phase leaving the bottom of the column back into the top of the column. Carbon dioxide present in the ascending gas stream is dissolved out of the gas stream and can later be separated from chlorine without problems by distillation.

Abstract: A process for preparing tolylenediamine by hydrogenating dinitrotoluene with hydrogen in the presence of a suspended catalyst in a vertically upright reactor (1), at the upper end of which is arranged a motive jet nozzle (2) through which the reaction mixture drawn off from the reactor bottom, via an external loop, is sprayed into the upper region of the reactor (1) and then flows into a central inserted tube (4) which is arranged in the longitudinal direction of the reactor, flows through the latter from the top downward and flows upward again outside the inserted tube (4) in an internal loop motion, with a heat exchanger (6) in the interior of the reactor (1), through which cooling water flows, and absorbs some of the heat of reaction as it does so, with a feed for the dinitrotoluene at the upper end of the reactor (1) and a feed for the hydrogen at the lower end of the reactor (1), and wherein, in addition to the heat exchanger (6) arranged in the interior of the reactor (1), a further heat exchanger (W

Abstract: A process for preparing polyether polyols by reaction of the following starting materials: a) one or more alkylene oxides and, if appropriate, carbon dioxide and also b) one or more H-functional starter substances, in the presence of a catalyst, in a reaction unit having a plurality of parallel layers A, B which are microstructured so that each layer has a multiplicity of channels which are arranged parallel to one another and form a continuous flow path from one side of the plate to the opposite side of this, wherein a distribution device for introduction of the starting materials and the catalyst is provided at one end of the channels of the layers A and a collection device for the reaction mixture is provided at the other end of these is proposed.

Abstract: The present invention relates to template-free clathraslls whose framework comprises essentially SO2, wherein the crystals of the ciathrasils have the platelet-like morphology of a sheet silicate. The present invention further relates to a process for preparing these template-free clathrasils and also to their use as absorbent, as seed crystals for the synthesis of ciathrasil membranes of the same zeolite type and in the form of dense layers which function as gas separation membranes having a molecular sieving action.

Abstract: The invention relates to a process for the preparation of sodium dithionite, comprising the steps (a) provision of a synthesis batch comprising sodium formate, sulfur dioxide and an alkaline sodium compound in aqueous methanolic solution with formation of a sodium dithionite mother liquor, (b) isolation of sodium dithionite from the sodium dithionite mother liquor, a residual mother liquor being obtained, (c) separation of methanol from the residual mother liquor, (d) separation of the residual mother liquor into a thiosulfate-rich first part-stream and a thiosulfate-poor, formate-containing second part-stream by means of nanofiltration, (e) concentration of sodium formate in the second part-stream and (f) recycling of the concentrated second part-stream to process step (a).

Abstract: A process for the preparation of aqueous solutions of glucans having a ?-1,3-glycosidically-linked main chain and side groups having a ?-1,6-glycosidic bond by fermentation of fungal strains. The fungal strains secrete the glucans into the fermentation broth, in an aqueous culture medium, and the separation of the glucans from the fermentation broth is effected using asymmetrical filter membranes.

Abstract: The present invention relates to a process for the preparation of nanoparticulate zinc oxide in the form of aqueous suspensions or in the form of pulverulent solid. Furthermore, the invention relates to the use of zinc oxide particles and suspensions prepared in this way in cosmetic sunscreen preparations, as stabilizer in plastics, in paints, in coatings and as antimicrobial active ingredient.

Abstract: The present invention relates to a process for preparing an aqueous polymer dispersion by free-radical emulsion polymerization of a monomer mixture which comprises N,N-diethylaminoethyl methacrylate, to the polymer dispersion obtainable by this process, and to the use thereof.

Abstract: The present invention relates to a process for the continuous preparation of a 1,3-dioxolan-2-one wherein a discharge from the reaction zone is subjected to a fractionation by means of a semipermeable membrane in order to separate off polymeric by-products.

Abstract: A process for producing a liquid formulation of salts of sulfonated azo dyes by coupling an at least equimolar amount of diazotized aminoarylsulfonic acids I H2N—Ar—SO3H??(I), where Ar is phenylene (which may be monosubstituted by sulfo) or naphthylene (which may be mono- or disubstituted by sulfo and/or monosubstituted by hydroxyl) onto the coupling product of an unsubstituted or methyl-substituted phenylenediamine with itself comprises dissolving the azo dye in a basic medium and then subjecting the solution to a nanofiltration.

Abstract: The invention relates to a process for preparing aromatic amines by catalytic hydrogenation of the corresponding nitro compounds, in particular for preparing toluenediamine by hydrogenation of dinitrotoluene, wherein hydrogenation catalysts in which a mixture of nickel, palladium and an additional element selected from the group consisting of cobalt, iron, vanadium, manganese, chromium, platinum, iridium, gold, bismuth, molybdenum, selenium, tellurium, tin and antimony is present as active component on a support are used.

Abstract: The present invention relates to methods of producing surface-modified nanoparticulate particles at least of one metal oxide, metal hydroxide and/or metal oxide hydroxide, and aqueous suspensions of these particles. Furthermore, the invention relates to the surface-modified nanoparticulate particles, obtainable by these methods, at least of one metal oxide, metal hydroxide and/or metal oxide hydroxide and aqueous suspensions of these particles, and to their use for cosmetic sunscreen preparations, as stabilizer in plastics and as antimicrobial active ingredient.

Abstract: A process is described for continuously hydrogenating unsaturated compounds, in which particles of a first hydrogenation catalyst are suspended in a liquid phase in which an unsaturated compound is dissolved, the liquid phase, in the presence of a hydrogenous gas at a first partial hydrogen pressure and at a first temperature, is conducted through a packed bubble column reactor in cocurrent counter to the direction of gravity, the effluent from the bubble column reactor is sent to a gas-liquid separation, the liquid phase is sent to a crossfiltration to obtain a retentate and a filtrate, the retentate is recycled into the bubble column reactor and the filtrate, in the presence of a hydrogenous gas at a second partial hydrogen pressure and at a second temperature, is passed over a bed of a second hydrogenation catalyst, wherein the second partial hydrogen pressure is at least 10 bar higher than the first partial hydrogen pressure.

Abstract: The invention relates to a process for preparing aromatic amines by hydrogenation of nitroaromatics in the presence of catalysts, in which a fluid reaction mixture which comprises amines and from which the catalysts are separated off is formed in a reactor. After the catalysts have been separated off, a measurement of the absorption of UV/VIS radiation by the reaction mixture is carried out to determine the concentration of nitro and nitroso compounds in the reaction mixture.

Abstract: The present invention relates to methods of producing surface-modified nanoparticulate particles at least of one metal oxide, metal hydroxide and/or metal oxide hydroxide, and aqueous suspensions of these particles. The invention further relates to the surface-modified nanoparticulate particles, obtainable by these methods, at least of one metal oxide, metal hydroxide and/or metal oxide hydroxide and aqueous suspensions of these particles, and to their use for cosmetic sunscreen preparations, as stabilizer in plastics and as antimicrobial active ingredient.

Abstract: The invention relates to a process for preparing aromatic amines by hydrogenation of nitroaromatics in the presence of catalysts, in which a fluid reaction mixture which comprises amines and from which the catalysts are separated off is formed in a reactor. After the catalysts have been separated off, a measurement of the absorption of UV/VIS radiation by the reaction mixture is carried out to determine the concentration of nitro and nitroso compounds in the reaction mixture.

Abstract: A process for preparing polyether polyols by reaction of the following starting materials: a) one or more alkylene oxides and, if appropriate, carbon dioxide and also b) one or more H-functional starter substances, in the presence of a catalyst, in a reaction unit having a plurality of parallel layers A, B which are microstructured so that each layer has a multiplicity of channels which are arranged parallel to one another and form a continuous flow path from one side of the plate to the opposite side of this, wherein a distribution device for introduction of the starting materials and the catalyst is provided at one end of the channels of the layers A and a collection device for the reaction mixture is provided at the other end of these is proposed.

Abstract: A process for aminating hydrocarbons comprises physically removing hydrogen from the reaction mixture.

Abstract: A process for the production of a composite membrane, one or more microporous separation layers comprising a zeolite of the MFI type being produced by hydrothermal synthesis on a porous substrate, wherein one or more additives from the group consisting of linear (C1-C4)-alcohols, ammonia, primary, secondary and tertiary amines having in each case (C1-C4)-alkyl radicals, (C1-C4)-aminoalcohols and (C3-C4)-ketones are added to the synthesis solution for the hydrothermal synthesis.

Abstract: The invention provides a process for preparing isocyanates by reacting the corresponding amines with phosgene in the presence of solvents, wherein compounds which form salt melts with hydrogen chloride are used as solvents.