Basf Aktiengesellschaft

Hans Christoph Horn

Johannes Grimmer

Eckhard Hetzel

Roland Spahl

Bernhard Rieger

Manfred Stroezel

Peter Tonne

Michael Jolyon Sprague

Hans-Joachim Muller

Otto Kumberger

Klaus Hess

Christopher William Rieker

Gerhard Kilpper

Ludwig Vogel

Adnan S Abu-Surrah

Norbert Neth

Ingo H Dorn

Hans-Ingo Joschek

Wolfgang J&uuml;rgen P&ouml;pel

Gerhard W Rotermund

Marco Millies

Gunter Dinkhauser

Production of solids by precipitation

Thermoplastic elastomeric carbon monoxide/olefin copolymers

A process for decomposing organohalogen compounds which are present in dust-laden gases which have a carbon content of less than 0.6% by weight, by oxidative breakdown with the aid of solid catalysts suitable for this purpose, wherein

Decomposition of organohalogen compounds in dust-laden-waste gases

Very pure riboflavin (I) is obtained by a process in which the riboflavin is dissolved in dilute aqueous alkali metal hydroxide solution, if necessary the alkaline solution is purified by treatment with active carbon or with a solvent which is insoluble or only slightly soluble in water, the resulting alkaline solution of I is introduced into water which is at 90.degree.-100.degree. C. and to which an acid has been added in an amount such that the reaction mixture is brought to a pH of from 6.5 to 0.8, the temperature being maintained at from 40.degree. to 100.degree. C., the reaction mixture is kept at from 90.degree. to 100.degree. C. for from 10 to 80 minutes and cooled, and I is then isolated.

Purification of riboflavin

Riboflavin of the formula I ##STR1## is prepared by condensation of a 4,5-dimethyl-N-(D)-ribityl-2-phenylazoaniline of the formula II ##STR2## where X is H, --Cl, --NO.sub.2 or --CH.sub.3 in the o- or p-position, with barbituric acid of the formula III ##STR3## in the presence of an acidic condensing agent in an inert organic solvent by an improved process in which the reaction is carried out in an aliphatic diol or triol derivative of the general formula IV ##STR4## where R.sup.1 is H or CH.sub.3, R.sup.2 is H or CH.sub.3 -- or, when n is 0, is CH.sub.3 --CO--O--CH.sub.2 --, R.sup.3 is CH.sub.3 --, C.sub.2 H.sub.5 -- or CH.sub.3 --, R.sup.4 is CH.sub.3 --CO--, or is H when R.sup.3 is CH.sub.3 -- or C.sub.2 H.sub.5 --, and n is 0 or 2, preferably 0, having a boiling point of 80.degree.-180.degree. C., or in a mixture of these as a solvent. In this process, the riboflavin is obtained in particularly pure form and in very good yields.

Preparation of riboflavin

An improved process for the purification of crude riboflavin which has been prepared by condensation of an N-(D)-ribityl-2-arylazo-4,5-dimethylaniline and barbituric acid or another N-(D)-ribityl-4,5-dimethyl-aniline derivative with a barbituric acid derivative, by dissolving the crude riboflavin in sulfuric acid or phosphoric acid which has been diluted with water and oxidizing the impurities by treating the solution with hydrogen peroxide, or by dissolving the riboflavin in dilute nitric acid at elevated temperature and then isolating the pure riboflavin by precipitation with water, wherein the mineral acid solution of the riboflavin and the oxidizing agent or the solution of the riboflavin in 20 to 70% strength by weight nitric acid is heated extremely rapidly to a temperature at which the solution clearly changes color from greenish to yellow-orange, the solution is kept at this temperature for from 1 to 50, seconds and the oxidation reaction is then interrupted by addition of water. The best results are achieved in this process if from 20 to 65% strength by weight nitric acid is used simultaneously as the acid and oxidative agent and if, after the change in color, the mineral acid solution, in particular the nitric acid solution, is passed, immediately or after prior interruption of the oxidation reaction by addition of cold water, into hot water at from 90.degree. to 100.degree. C. and the suspension thereby formed is kept at this temperature for about a further 10-30 minutes.

A process for the continuous preparation of isatoic anhydrides by two-stage reaction of an alkali metal phthalamate and/or alkali metal phthalimidate with an alkali metal hypohalite, the first stage being carried out substantially adiabatically and both stages being carried out at high flow rates, wherein phthalimide and/or phthalamic acid is first dissolved in a certain amount of an alkali metal hydroxide solution, the resulting solution is mixed with a hypohalite and reacted at a particular temperature, acid is then added and the reaction is completed at a particular temperature. The compounds obtainable by the process of the invention are valuable starting materials for the preparation of dyes, crop protection agents and scents.

Continuous preparation of isatoic anhydride

Continuous manufacture of phthalimide by reaction of phthalic anhydride with ammonia and washing the offgas with a melt containing phthalimide. The product is a starting material for the manufacture of dyes, pesticides and pigments, especially copper phthalocyanines.

Continuous manufacture of phthalimide

Growing community of inventors

Lambsheim, Germany

Hans Christoph Horn