Abstract: A process is provided for the preparation of aqueous silica sols having a particle size of 27 to 72 nm. by adding fresh acidic silica sol into the reactors of a multi stage cascade reactor wherein the reactors contain aqueous solution of colloidal silica sol of a pH of 8 or above. Each successive stage of the cascade reactor is supplied with overflow from the preceding stage. Alkaline compounds, such as alkaline sodium silicate solution, alkaline potassium silicate solution, sodium hydroxide solution or potassium hydroxide solution, are introduced into the first reactor or first reactors so that a pH value in the range of 8 to 12.5 is established in the reactors.

Abstract: Use of diethyl dodecylphosphonate (DEDP) for the extraction of acids and metal salts from aqueous solutions.

Abstract: A method for the decomposition of chromium ore in a directly heated revolving tube is described, in which oxygen-containing gases are introduced into the revolving tube by means of below-bed nozzles.

Abstract: This invention relates to an improved process for the production of 2-phosphono-butane-1,2,4-tricarboxylic acid (PBTC) and the alkali metal salts thereof, in which process dialkyl phosphite, preferably dimethyl or diethyl phosphite, and ethene-1,2-dicarboxylic acid dialkyl ester, in particular the dimethyl or diethyl ester of maleic acid and/or fumaric acid, are initially reacted in the presence of a basic catalyst to yield a phosphonosuccinic acid tetraalkyl ester, the resultant ester is thereupon reacted without further working up with acrylic acid alkyl ester, preferably methyl or ethyl acrylate, in the presence of an alkaline catalyst and the reaction product obtained in this manner is saponified without further working up to yield PBTC or the alkali metal salts thereof. The product when mixed with bleaching lye exhibits reduced chlorine depletion.

Abstract: In the production of an organochlorosilane by reaction of silicon with at least one of an alkyl or aryl chloride in the presence of a copper catalyst, the improvement which comprises employing as the silicon fine-particle silicon containing surface-bound chlorine produced by contacting fine-particle silicon in reactive form with gaseous or liquid chlorine.

Abstract: A process for the recovery by distillation of tributyl phosphate (TBPO) from spent hydraulic oils, which are employed particularly in aircraft used for civilian air traffic.

Abstract: The present invention relates to novel polyether-substituted compounds of imides and their use as surface-active agents.

Abstract: Novel mixtures containing at least one polysiloxane and at least one reactive filler, at least one pigment and/or unreactive filler and optionally other additives, their preparation and use in coating. Preferably they are largely free of organic polymers.

Abstract: In the preparation of dimethylamine-borane by reacting an alkali metal or alkaline earth metal borohydride with a dimethylammonium salt, the improvement which comprises effecting the reaction in a liquid mixture comprising dimethylamine as a solvent and an additional organic solvent.

Abstract: A chemically linkable mixture comprising(a) about 98 to 80% by weight of a fluoroelastomer bearing lateral olefinic double bonds,(b) about 2 to 20% by weight of at least one of a silicone oligomer, silicone elastomer and a fluorosilicone elastomer containing Si--H groups, and(c) a catalyst containing at least one of a noble metal and an organic peroxide.Fluororubbers made therefrom are distinguished by excellent physical properties.

Abstract: A process for improving the storage life of a one-component silicone paste containing an alkali metal phosphate and which cures with elimination of acetic acid on exposure to atmospheric moisture, which comprises adding to such paste an acidic additive bearing the functional group --SO.sub.3 H or hydrogen chloride in a concentration sufficient to convene the alkali metal phosphate into the alkali metal salt of the acidic additive.

Abstract: A method for manufacturing alkali chromates by the reacting of chromium ore with alkali compounds and oxidation in an atmosphere containing at least 50% oxygen is described, in which the mixture consisting of chromium ore, alkali compound and optionally leaning materials is heated in a first stage in an atmosphere containing not more than 5 vol. % oxygen to a temperature between 1000.degree. and 1 400.degree. C., and in a second stage is oxidized at a lower temperature of 900.degree. to 1 070.degree. C. with supply of an atmosphere containing at least 50% oxygen.

Abstract: Fluoroalkyl- and fluoroaryl-group-containing imides and their salts of general formula (I) ##STR1## wherein R.sub.F is a fluoroalkyl group with 1 to 18 carbon atoms, a fluoroaryl group with 6 to 12 carbon atoms or a mixed fluoroalkylaryl group with 7 to 18 carbon atoms, wherein the carbon chain can also be interrupted by oxygen atoms,R.sub.H is an alkyl group with 1 to 30 carbon atoms, an aryl group with 6 to 12 carbon atoms or a mixed alkylaryl group with 7 to 30 carbon atoms, wherein the carbon chain of the group can also be interrupted by oxygen, nitrogen or sulphur atoms,Y.sub.1 and Y.sub.2 independently of each other represent a ##STR2## X is a hydrogen cation or a uni- or multivalent cation, m is a whole number from 0 to 6, andz is a whole number from 1 to 7 corresponding to the charge of the cation X.

Abstract: A process for the removal of organic impurities and dissolved salts from hydrazine hydrate and aqueous solutions thereof by distillation of the hydrazine hydrate under reduced pressure, passing the hydrazine hydrate vapor through an adsorbent, and condensing the vapor.

Abstract: Process for the production and concentration of alkaline silica sols containing nonaggregated, spherical SiO.sub.2 particles with a diameter of .gtoreq.1 nm starting with SiO.sub.2 concentrations of 4-8% by weight, using microporous membrane filters.

Abstract: The present invention relates to fluorinated carboxylic acid esters of phosphono- and phosphinocarboxylic acids containing hydroxyl and/or mercapto groups, their use as waterproofing and/or oil-repellency agents, and a method for their preparation.

Abstract: The present invention relates to novel polyether-substituted compounds of imides and their use as surface-active agents.

Abstract: The present invention relates to fluorinated carboxylic acid esters of phosphonocarboxylic acids containing acrylate and/or methacrylate groups, their use as waterproofing or oil-repellency agents, and a method for their preparation.

Abstract: The invention relates to a process for purifying industrial anhydrous hydrogen fluoride by means of oxygen difluoride.

Abstract: The invention relates to an improved process for the production of liquid amine adducts of fluorine-containing amides, in which the compounds are synthesized in the absence of solvents in two process steps without the synthesis of intermediate products.