Hoechst Aktiengesellschaft

Benckiser-knapsack Gmbh

Theodor Auel

Gero Heymer

Franz-Josef Dany

Horst Staendeke

Joachim Kandler

Hans-Werner Stephan

Dieter Bergner

Horst-Dieter Wasel-Nielen

Jurgen Russow

Werner Klose

Hannsjorg Ulrich

Theodor Riehm

Wilhelm Spatz

Nikolaj Medic

Werner Kloss

The invention relates to a process for making 1-aminoalkane-1,1-diphosphonic acids of the general formula (I): ##STR1## in which R stands for an aliphatic hydrocarbon radical having from 1 to 12 carbon atoms. To this end, the invention provides:

Process for the manufacture of 1-aminoalkane-1,1-diphosphonic acids

A process for producing polyalcohols such as xylite from deciduous wood wherein the wood is hydrolyzed with dilute mineral acid to produce a sugar solution which is deionized and decolorized in an ion exchanger and hydrogenated to produce a polyalcohol solution which is also decolorized and deionized by ion exchange and from which pure polyalcohol is thereafter separated by crystallization, further comprising dispensing with neutralization of the acid in the sugar solution after hydrolysis, deionizing and decolorizing both the sugar solution and the polyalcohol solution in the same ion exchanger, eluting acetic acid taken up by the ion exchanger from the polyalcohol solution and displacing polyalcohol solution from the exchanger with the acid containing sugar solution, washing the ion exchanger with water only after ion exchange of the sugar solution, removing the bulk of the acetic acid from the sugar solution by evaporating the sugar solution to a higher concentration than the concentration customarily utilized for hydrogenation, and rediluting the sugar solution prior to hydrogenation with the exchanger wash water.

Xylose and xylitol separately purified in same ion exchanger

For the electrolysis of an aqueous alkali metal chloride solution in a membrane cell with a perfluorinated cation exchange membrane it is important that there is only a minimum amount of cations of polyvalent metals, such as calcium. Otherwise, deposits within the membrane will occur, among other effects. It has been found that the disturbances caused by the above-mentioned cations can be considerably reduced, if an aliphatic polybasic phosphonic acid or the alkali metal salt thereof is added to the alkali metal chloride solution.

Process for alkali metal chloride electrolysis

The invention provides stabilized pulverulent red phosphorus. It comprises a homogeneous blend of red phosphorus particles with a size of at most about 2 mm and a metal compound of the second or third group of the Periodic System as an oxidation stabilizer, wherein the metal compound is the aluminum, magnesium, calcium or zinc salt of an alkyl-, cycloalkyl-, aryl- or aralkylphosphonic acid having 1 to 20 carbon atoms, the metal compound being present in the homogeneous blend in a proportion of about 0.5 to 5 weight %.

Stabilized red phosphorus and process for making it

Corrosion and deposition of boiler scale in water-conveying systems are inhibited. To this end the water is admixed with at least one carboxy-alkane compound of phosphorus of the general formula: ##STR1## in which each of the substituents R.sup.1, R.sup.2, R.sup.3, and R.sup.4 stands for hydrogen or an alkyl group having from 1 to 4 carbon atoms, R.sup.5 stands for hydrogen, an OH-group or an alkyl group having from 1 to 3 carbon atoms, and n stands for 0 or 1, or with at least one water-soluble salt thereof.

Process for inhibiting the corrosions and deposition of boiler scale in

Production of 2-phenyl-ethylene phosphonic acid by reacting styrene with phosphorus pentachloride in a molar ratio of about 1 : 2 in liquid phase and hydrolyzing the resulting complex 2-phenyl-ethylene phosphonic acid tetrachloride with water. The reaction is more particularly started with the use as the liquid phase of the equimolar mixture of 2-phenyl-ethylene phosphonic acid dichloride and phosphorus oxychloride obtained as an intermediary product; styrene and phosphorus pentachloride are introduced thereinto with continuous agitation; resulting complex 2-phenyl-ethylene phosphonic acid tetrachloride is partially hydrolyzed by adding a predetermined quantity of water to an equimolar mixture of 2-phenyl-ethylene phosphonic acid dichloride and phosphorus oxychloride; a portion of the resulting clear solution is continuously used as the liquid phase and phosphorus oxychloride is continuously distilled off under reduced pressure from the balance portion of the solution; remaining 2-phenyl-ethylene phosphonic acid dichloride is hydrolyzed by continuous addition of overstoichiometric proportions of water to an aqueous solution of 2-phenyl-ethylene phosphonic acid; the aqueous solution is cooled and crystalline phosphonic acid is precipitated therefrom.

Growing community of inventors

Ilvesheim, Germany

Theodor Auel