Bayer Aktiengesellschaft

Walter Horstmann

Knut Hammerstrom

Gerhard Wolfrum

Edgar Muschelknautz

Heiko Herold

Richard Sommer

Alfons Dorlars

Otto Horak

Laszlo Imre

Heinrich Gold

Rolf Schimpf

Hans-Ulrich Alles

Ruthard Potthast

Kunz Brunner

Hans-Gerhard Leopold

Hans Trautwein

The present invention relates to an improved preparation process for 2-aminobenzene-1,4-disulphonic acids and the new compound 6-chloro-2-aminobenzene-1,4-disulphonic acid.

Process for the preparation of 2-aminobenzene-1,4-disulphonic acids and

New diaminoalkyldiphenyl ethers of the formula ##STR1## wherein R.sup.1 and R.sup.2 are identical or different and denote hydrogen or methyl, but R.sup.1 and R.sup.2 do not simultaneously represent methyl, are prepared by a process wherein alkyldiphenyl ethers of the formula ##STR2## wherein R.sup.1 and R.sup.2 have the above-mentioned meaning are acetylated, the diacetyl compounds obtained, in aqueous-alcoholic solution or suspension, are converted to the corresponding dioximes with hydroxylamine, the dried dioximes are subjected to a Beckmann rearrangement and thereafter the diacetylaminoalkyldiphenyl ethers formed are hydrolyzed by means of aqueous mineral acids or alkali metal hydroxide solutions to give the diamines. The new diaminoalkyldiphenyl ethers are used in the preparation of dyestuffs and polyurethanes and serve as monomers for the preparation of polymers.

Diaminoalkyldiphenyl ethers, a process for their preparation and their

2-Amino-6-nitrobenzothiazole is obtained with a high selectivity if, instead of unprotected 2-aminobenzothiazole, acylation products thereof are nitrated and the acyl groups are then split off. 2-Amino-6-nitrobenzothiazole is an important intermediate product for the preparation of valuable azo dyestuffs.

Process for the preparation of 2-amino-6-nitrobenzothiazole

A di- or tri-sulphonic acid hydrazide of an alkylated diphenyl ether, said hydrazide being of the formula ##STR1## wherein R.sub.1 and R.sub.2 are identical or different and represent halogen or a lower alkyl radical and R.sub.1 and R.sub.2 can denote hydrogen,

Alkyldiphenyl ether-sulphonic acid hydrazides, their preparation and

A process for the preparation of 1,4-diazobicyclo-(2,2,2)-octane by contacting piperazine with a catalyst at an elevated temperature, the catalyst containing silicon dioxide.

Process for the preparation of 1,4-diazabicyclo-(2,2,2)-octane

Solids obtained from drying gases in an atomizing or spray drier are separated in an apparatus the lower part of which comprises an axial guide mechanism, which is connected by a rotationally symmetrical cowl to an angled gas outflow pipe which initially leads upwards in the center, then at the level of the guide mechanism runs outward radially.

Apparatus for the mechanical separation of solids from drying gas in

In the degradation of organic compounds in an effluent by oxidizing the effluent at an elevated temperature with oxygen, the improvement which comprises effecting the oxidation at a redox potential of from about 300 to 600 millivolts, as measured with a platinum electrode against a silver-silver chloride electrode, at a temperature of from about 80.degree. to 250.degree. C and under a pressure of from about 30 to 200 bars. The redox potential may be maintained by an Fe.sup.2+ and/or Fe.sup.3+ ion system and the pH is advantageously below about 7.

Degradation of organic compounds in effluents by wet oxidation

The stilbene compound of the formula ##SPC1## Exists in three crystal modifications. Two of them are valuable as brighteners for preparing colorless detergents. The stilbene compound is prepared from the corresponding sulphonic acids, their mono- or di-sodium salts.

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Bergisch Gladbach, Germany

Walter Horstmann