Abstract: Aminomethanephosphonic acid aryl esters of the formula ##STR1## in which R.sup.1 is an aromatic radical and R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 independently of one another represent hydrogen atoms, ##STR2## groups, an optionally substituted C.sub.1-10 alkyl radical or an optionally substituted aromatic ring, or salts thereof.These aminomethanephosphonic acid aryl esters are useful as flameproofing agents in foams, thermoplastics and thermosets and as a crosslinking component in oligo-and polycondensates based on monomers containing hydroxy groups.

Abstract: A process for the preparation of alkali metal dichromates and/or chromic acid by electrolysis of alkali metal monochromate and/or alkali metal dichromate solution in electrolysis cells, the anode and cathode compartments of which are separated by cation exchange membranes, wherein the cation exchange membranes are single-layer membranes based on perfluorinated polymers having sulfonic acid groups as cation exchange groups, and an aqueous solution having a pH of 4 to 14 is produced in the cathode compartment of the cells.

Abstract: A dimensionally stable anode comprised ofa) an electrically conductive valve metalb) a conductive intermediate layer andc) an electrode coating of an electrocatalytically active substance, wherein the intermediate layer comprises one or more noble metals or their alloys which have been applied to the valve metal by deposition by electroplating from melts containing noble metal salts. This anode can be used in the production alkali metal dichromates and chromic acid by electrolysis of alkali metal monochromate and/or alkali metal dichromate solutions.

Abstract: A process for the production of chromic acid, comprising(a) dissolving ferrochrome in sulphuric acid and mother liquor from the subsequent crystallization of ammonium chrome alum, optionally with the addition of at least one of catholyte and anolyte overflow from the subsequent electrolysis,(b) removing undissolved constituents by filtration,(c) removing dissolved iron by the addition of at least one of ammonia and ammonium sulphate to the filtrate obtained, crystallizing iron ammonium sulphate and filtering,(d) crystallizing and filtering ammonium chrome alum from the remaining solution and returning the filtrate for dissolving ferrochrome in step (a),(e) dissolving the ammonium chrome alum in water,(f) precipitating and separating chromium-(III) hydroxide from the resulting solution by adding a base, optionally under reducing conditions,(g) dissolving the separated chromium hydroxide in chromic acid and optionally sulphuric acid so that either a single solution in chromic acid is obtained or two solutions a

Abstract: A process for the preparation of alkali metal dichromates and chromic acid by the electrolysis of monochromate and/or dichromate solutions in an electrolytic cell in which the anode and cathode chamber are separated by a cation exchanger membrane anolyte fluid containing dichromate and/or chromic acid being formed in the anode chamber and alkaline catholyte fluid containing alkali metal ions being formed in the cathode chamber, the improvement wherein the catholyte fluids are periodically replaced by a solution which is at a pH below 6.

Abstract: The present invention relates to a process for eliminating 1-phosphono-1-carboxycyclopentan-3-one (ketone) from, or reducing its content in, an aqueous solution of 2-phosphonobutane-1,2,4-tricarboxylic acid, characterized in that the solution is adjusted to a pH value of > 6 using an aqueous inorganic base, particularly sodium hydroxide, and aqueous bleaching liquor is subsequently added in a molar ratio of NaOCl to ketone of >5:1.

Abstract: A process for the preparation of chromic acid by the electrolysis of dichromate and/or monochromate solutions in electrolytic cells in which the anode chamber and the cathode chamber are separated by a cation exchanger membrane, the improvement wherein the chromic acid content of the solution in the anode chamber is periodically increased above that of a continuous operating state.

Abstract: A process for the production of chromic acid by the multistage electrolysis of dichromate and/or monochromate solutions in two-compartment electrolysis cells, of which the anode and cathode compartments are separated by cation exchanger membranes, at temperatures in the range from 50.degree. to 90.degree. C., the dichromate and/or monochromate solutions being obtained by the digestion of chrome ores and leaching, the improvement wherein, optionally after the removal of aluminum, vanadium and other impurities, the monochromate solution obtained after leaching is adjusted at 20.degree. to 110.degree. C. to a pH value of from 8 to 12 by the addition and/or in situ formation of carbonate in a quantity of from 0.01 to 0.18 mol/l (for 300 to 500 g/l Na.sub.2 CrO.sub.4, converted with CO.sub.

Abstract: A process for the preparation of alkali metal dichromates and chromic acid by the electrolysis of monochromate and/or dichromate solutions in an electrolytic cell in which the anode and cathode chambers are separated by cation exchange member, the improvement wherein the formation of deposits on the membrane is prevented comprising continuously introducing a solution containing chromate at a pH of about 3 to 10 into the cathode chamber during the electrolysis.

Abstract: The invention relates to thermoplastic polycarbonate molding compounds containing polycarbonates, copolymers, phosphorus compounds, tetrafluoroethylene polymers and, optionally, graft polymers and also further additives and other thermoplastics and also stabilizers, pigments, flow aids, mold release agents, antistatic agents and/or other flameproffing agents, characterized in that they contain as phosphorus compounds those corresponding to formula (I) ##STR1## and to a process for the production of the polycarbonate molding compounds.

Abstract: A process for the production of alkali dichromates and chromic acid by electrolysis of alkali monochromate or alkali dichromate solutions wherein the anodes used in the electrolysis are dimensionally stable anodes of valve metals activated by electrodeposition of noble metals and/or noble compounds from melts containing noble metal salts.

Abstract: This invention relates to an improved process for the continuous production of 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC) and alkali metal salts thereof, in which dialkylphosphite, and ethene-1,2-dicarboxylic acid dialkyl ester, are reacted in the presence of a basic catalyst to form phosphonosuccinic acid tetraalkyl ester, the ester thus obtained is directly reacted with alkyl-acrylate, in the presence of an alkaline catalyst and the reaction product thus obtained is directly hydrolyzed to PBTC or alkali metal salts thereof.

Abstract: An improved process for the preparation of dimethylmaleate by the esterification of maleic acid anhydride, maleic acid monomethylester, maleic acid or mixtures thereof with methanol in the presence of catalytic quantities of sulphuric acid, which comprises carrying out the esterification reaction within 20 to 120 minutes in a multistage bubble cap column reactor at temperatures of from 90.degree. to 140.degree. C. and with methanol excesses of from 0.4 to 2.0 mole per mole of the dimethylmaleate to be produced.

Abstract: A holding device using a vacuum clamp arrangement has a suction box closed by a suction plate having a holding surface provided with a plurality of suction bores extending from the holding surface into the suction box. Each of the suction bores has an enlarged expanded bore portion inwardly spaced from the holding surface to form a valve chamber which valve chamber is closed by an inner section of the suction bore between the chamber and the suction box and each of the valve chambers loosely receives the shaped valve reed which will close the inner section of the suction bore for each of the suction bore arrangements which is not covered by the sheet placed on the holding surface. This simple structure keeps vacuum losses low and, therefore, enables utilizing a relatively small vacuum pump for the device.

Abstract: This invention relates to a process for the production of branched polyphosphates.

Abstract: This invention relates to new polyphosphates, and to the production and use thereof.

Abstract: Thermoplastic, branched aromatic polyphosphonates with average molecular weights (number average M.sub.n) of from 11,000 to more than 200,000, obtainable by transesterifying (a) from 97 to 100 moles of at least one diaryl phosphonate, and (b) from 0 to 3 moles of at least one triaryl phosphate--the sum of the moles of (a) and (b) being 100--with (c) from 90 to 99 moles of at least one aromatic dihydroxy compound, and (d) from 0 to 3 moles of at least one aromatic trihydroxy or tetradhydroxy compound--with the proviso that at least one of the components (b) and (d) is present in a quantity of at least 0.001 mole and that, where (b) and (d) are used, the maximum limit on the moles is 3.0.

Abstract: The present invention relates to a new process for the production of aryl phosphonyl compounds by the catalytic rearrangement of aryloxy phosphines in the presence of aromatic bromine compounds and zero-valent nickel.

Abstract: A process for the preparation of an alkane phosphonic acid diaryl ester or an alkane phosphinic acid aryl ester of the formula ##STR1## wherein R.sup.1 is C.sub.1 -C.sub.20 alkyl or alkenyl group,R.sup.2 is a C.sub.1 -C.sub.20 alkyl or alkenyl group or a C.sub.6 -C.sub.10 aryl or aryloxy group,R.sup.3 is C.sub.6 -C.sub.10 aryl group,k is 0 or 1,p is 1 or 2,k+p=2,plus an alkane phosphonic acid diaryl ester, alkane phosphinic acid aryl ester or phosphine oxide of the formula ##STR2## R.sup.4 and R.sup.5 each independently is C.sub.1 -C.sub.20 alkyl group, a C.sub.6 -C.sub.10 aryl group or a C.sub.6 -C.sub.10 aryloxy group,R.sup.6 is C.sub.1 -C.sub.

Abstract: The instant invention relates to a process for producing stable equilibrium mixtures of carbodiimides, uretone imines and organic isocyanates and storage-stable solutions of carbodiimides and uretone imines in polyisocyanates which are free from carbodiimide groups. Either the carbodiimide, or the uretone imine, or both, may contain isocyanate groups. The invention relates to the process for the preparation of these products by so-called heterogeneous catalysis and the use of these products for the production of polyurethane resins.