Abstract: The present invention relates to a process for separating organic acids from aqueous solutions by the use of electrochemical processes such as electrolysis and electrodialysis. These processes can be used, for example, to purify aqueous solutions produced in aldol condensation processes.

Abstract: A process for the removal of ethers and/or PAH's from water, such as contaminated groundwater, is provided that proceeds by initially separating off solid constituents and then adsorbing ethers and polycyclic aromatic hydrocarbons to an adsorber resin, then, as needed, desorbing the adsorbed compounds with steam and regenerating the adsorber resin with an acid, to provide purification of highly polluted groundwater to such a substantial extent that the groundwater can be added to flowing surface waters without problem, and, if desired, used as cooling water or, after further biological purification, as drinking water.

Abstract: Solid polyurethane hardeners (curing agents) having triazine groups, are prepared by reacting polyaddition compounds with a second compound having a >C═N— group. The polyaddition compounds are prepared by reacting a uretdione-functional polyisocyanate with a hydroxy-functional chain extender.

Abstract: Inversion carbon blacks and a method for their manufacture are disclosed. The inversion carbon blacks have a lower rolling resistance with identical or improved wet skid behavior. The particle size distribution contains a smaller proportion of particles with large diameters. This leads to an improved abrasion behavior of rubber compounds which were prepared using these carbon blacks. The inversion carbon blacks can be manufactured in conventional carbon black reactors by controlling the combustion in the combustion chamber in such a manner that carbon black nuclei form, which are immediately brought into contact with the carbon black raw material. The carbon blacks present a lower proportion of larger particles if the additions of combustion air and carbon black raw material are increased in an appropriate manner.

Abstract: An oligomerized polyorganosiloxane cocondensate which may be obtained, in part, by mixing an water-soluble amino-functional organosilane represented with at least one of the followoing: a fluoro-functional organosilane, an organosilane, and an organosilane. The cocondensate may be used, for example, in a method of treating surfaces.

Abstract: A process for the preparation of guanine, by reacting 2,4-diamino-5-formylamino-6-hydroxypyrimidine (DAFHP) with formic acid, in the absence of formalize. The process may be conducted with the addition of water and at reflux temperature.

Abstract: Alkoxysilanes are prepared by a process, comprising: (i) reacting a chlorosilane with an alcohol in a water-free and solvent free phase with removal of the liberated hydrogen chloride; (ii) transferring the resultant product mixture into a liquid phase to be distilled and adding a metal alcoholate to the product mixture in the liquid at a temperature in the range from 10-60° C., and thoroughly mixing the neutralized product mixture, said alcoholate being employed in an equimolar amount or in a stoichiometric excess based on the amount of acidic chloride, and (iii) purifying the treated product mixture by distillation under reduced pressure, thereby preparing alkoxysilanes which are low in acidic chloride or essentially free of acidic chloride.

Abstract: A process for reducing the nitrogen oxides content of the exhaust gas from an internal combustion engine includes treating the exhaust gas in an electric gas discharge such that at least one of nitrogen dioxide or nitric acid are formed from nitrogen oxides in the exhaust gas; storing the nitrogen dioxides and/or the nitric acid in the form of nitrates on a nitrogen oxides storage material during phases when the engine operates with a greater than a stoichiometric air/fuel ratio (i.e., the storage phase); decomposing the nitrates to give nitrogen oxides during brief phases when the engine operates with a less than the stoichiometric air/fuel ratio (i.e., the desorption phase); and reducing the nitrogen oxides which are released from the storage material to nitrogen. The nitrogen oxides storage material may be located in an electric gas discharge zone, and the exhaust gas may be passed through the discharge and then over the storage material.

Abstract: Sulfanylsilanes of the formula X1X2X3Si—A—S—SiR1R2R3 are prepared by reacting mercaptosilanes of the formula X1X2X3Si—Alkyl—SH with chlorosilanes Cl—SiR1R2R3. They are used as coupling agents in rubber mixtures.

Abstract: A process for preparing guanine, in which 2,4-diamino-5-formylamino-6-hydroxypyrimidine (DAFHP) in formic acid is reacted at superatmospheric pressure, optionally in the absence of formamide and/or in the presence of catalytic amounts of an additive which acts as a reducing agent.

Abstract: A process for producing, on a metallic substrate, a geometric metal structure having a precise contour, including the steps of: solder coating a solder paste onto the substrate by screen printing to create the geometric metal structure, the solder paste comprising an organic binder system, and 80 to 95 weight % of a mixture of a nickel-based solder and a pulverulent alloy of nickel with at least one member selected from the group consisting of chromium, molybdenum, tungsten, manganese and iron, provided as a higher-melting metallic filler, wherein a weight ratio of solder to filler is 2-6:1, an average grain size of the solder is between 10 and 50 &mgr;m, and a grain size ratio of solder to filler, relative to the average grain size is from 0.5-2.5:1; drying the structure; decomposing the organic binder system present in the solder paste, without leaving a reside, by a heat treatment; and raising the temperature until the resulting solder material liquifies.

Abstract: A toner or a mixture of toners, comprises a pyrogenically synthesized alumina-silica mixed oxide as a component in combination with other components necessary to complete a toner formulation. The surface of the mixed alumina-silica oxide material.

Abstract: A process for the preparation of mixtures of organosilicon disulfanes with a high disulfane content includes first reacting finely divided sodium and sulfur in an organic solvent, and then reacting the resulting Na2Sx, product further with a halogenoalkylalkoxysilane to give the desired product.

Abstract: A ferroceneylphosphine ligand and complexes prepared therefrom for homogeneous catalytic enantioselective hydrogenation, the ligand having the formula (I): Another aspect of the invention is directed to a ferroceneylphosphine ligand of formula (II),

Abstract: A partially hydrophobic precipitated silica having a methanol wettability of 10 to 49%, in particular with a DBP uptake on a dry basis of greater than 250 g/100 g and a mean particle size of 1 to 12 &mgr;m and/or a carbon content of 0.3 to 1.85% and/or a loss on drying of 2.6 to 10.0% and/or a pH value of 5.5 to 10.0, is prepared by mixing the amount of water-repellent agent with the precipitated silica suspension at very short residence time and low pH value, filtering off the solid substance, washing free of salt, drying, post-treating thermally and milling. The partially hydrophobic precipitated silica can be used in active substance formulations and active substance formulations of hydrolysis-sensitive substance and in defoaming agents.

Abstract: A process for preparing alkali metal alkoxides of alcohols comprising reacting an alkali metal amalgam with an alcohol having at least 3 carbon atoms in the presence of a powder catalyst comprising a transition metal carbide, nitride or carbonitride, to form a reaction mixture, wherein the reaction mixture is subjected to ultrasound during reaction.

Abstract: A method for the production of D-pantothenic acid by the fermentation of microorganisms of the family Enterobacteriacae producing D-pantothenic acid which is characterized in that strains are used which a) Contain the plasmid pFV31 and/or pFV202 and that b) A panD gene and optionally other nucleotide sequences coding for aspartate-1-decarboxylase are enhanced, especially overexpressed in these microorganisms, c) The pantothenic acid is enriched in the medium or in the cells of the microorganisms and d) The pantothenic acid formed is isolated.

Abstract: The present invention relates to a process for neutralizing and reducing the residual halogen content in alkoxysilanes and alkoxysilane-based compositions, which includes treating an alkoxysilane having a residual content of acidic halide, or a corresponding alkoxysilane-based composition, with metallic magnesium in the presence of an alcohol and separating off the resulting solids.

Abstract: A process for preparing an alkoxysilane with an acidic chloride content of less than 10 ppm by weight, comprising:reacting a chlorosilane with an alcohol in a water-free and solvent-free phase to form a product mixture containing alkoxysilane and residual acidic chloride, with removal of resultant hydrogen chloride from the product mixture,then adding liquid or gaseous ammonia, in an amount corresponding to a stoichiometric excess, based on the content of acidic chloride, to form an ammonia-containing product mixture,treating the ammonia-containing product mixture at a temperature between 10 and 50.degree. C., wherein the ammonia and acidic chloride undergo neutralization, to form a crude product, and optionally, then separating off a salt formed in the course of neutralization, from the crude product, andrecovering the alkoxysilane by distilling the crude product.

Abstract: Mixtures of catenate and cyclic siloxane oligomers of formula I and II ##STR1## wherein the substituents R consist of 3-methacryloxypropyl or 3-acryloxypropyl groups and methoxy, ethoxy and/or propoxy groups alone or together with C.sub.1 -C.sub.18 alkyl, fluoroalkyl, isoalkyl or cycloalkyl groups and/or C.sub.6 -C.sub.12 aryl groups and where not more than one 3-methacryloxypropyl or 3-acryloxypropyl group is attached to one silicon atom and the degree of oligomerization of compounds of the formula I is within the range 2<m<25 and of compounds of the formula II is within the range 2<n<8 and the quotient of the molar proportion of Si/alkoxy groups is .gtoreq.0.5.