Ciba-geigy Corporation

Ciba-geigy Ag

Tibor Somlo

Franz Marti

Johann Regli

Walter Fischer

Jacques Gosteli

Gottfried Seifert

Eric Plattner

Jean Riethmann

Anton Hungerbuhler

Mauro Stagi

Alexander Davatz

Frantisek Gaspar

A process for the preparation of 1-nitroanthraquinone by oxidising 1-nitro-5,8,11,12-tetrahydroanthraquinone with oxygen, inorganic peroxo compounds or metal oxides.

Process for the preparation of 1-nitroanthraquinone

There is disclosed a process for the preparation of 1-aminoanthraquinones from 5-nitro-1,4,4a,9a-tetrahydroanthraquinones with a basic reducing agent, which process is carried out under pressure in the temperature range above 100.degree. C. and in an aqueous-organic medium. The process affords very pure 1-aminoanthraquinone, which is, inter alia, an important intermediate.

Process for the preparation of 1-aminoanthraquinones

Process for preparing 2-(2'-hydroxyphenyl)-benzotriazoles of the formula ##STR1## from 2-nitro-2'-hydroxyazobenzenes of the formula ##STR2## which comprises reducing a 2-nitro-2'-hydroxyazobenzene compound in a strongly basic medium in the presence of an aromatic dihydroxy or dioxo compound as catalyst and of an alcohol having more than one carbon atom. The 2-(2'-hydroxyphenyl)-benzotriazole compounds are known stabilizers for organic materials.

Novel process for preparation of benzotriazoles using aryldiols and

A process for the preparation of pure bromoanthraquinones by denitrobrominating corresponding nitroanthraquinones is described. The process comprises treating nitroanthraquinones of the formula I ##STR1## wherein X is hydroxy, mercapto, carboxy or halogen and m is 1, 2, 3 or 4 and n is 1 or 2, in the temperature range from 200.degree. to 350.degree. C. Bromoanthraquinones of more than 95% purity are valuable starting materials for dye synthesis and can be used directly without further purification.

Process for the preparation of bromoanthraquinones

A process for purifying crude monochloro- or monobromoanthraquinone is described. In this process, monochloro- or monobromoanthraquinone which contains by-products as impurities is mixed with a hot non-polar aliphatic solvent in such a ratio that more than half of the crude product goes into solution and the remainder which contains the impurities forms a second lower phase, said eutectic melt is separated, and the saturated solution is allowed to cool, and the monochloro- or monobromoanthraquinone, which precipitates in pure form, is isolated.

Process for purifying crude monochloro- and monobromoanthraquinone

A process for the production of 2-halo-4-bromophenols of the formula ##STR1## in which X represents chlorine or bromine, is disclosed, which process comprises reacting a brominating agent with a 2-halophenol in the presence of a mixed catalyst consisting of a halide of zinc, iron, aluminium or cobalt, and a diphenyl sulfide of the formula ##STR2## in which R represents methyl or halogen, and n represents 0 to 3. The new process substantially avoids the formation of undesired 2,6-isomers and the 2-halo-4-bromophenols of the above formula are obtained in excellent yield and purity.

Process for producing 2-halo-4-bromophenols

The invention describes a process for the production of benzal or benzyl bromides which contain electrophilic substituents in the ortho- and/or para-position, or mixtures thereof, by the side-chain bromination of correspondingly substituted toluene, which comprises introducing elementary chlorine, under irradiation with visible light, into a two-phase system consisting of an aqueous phase and an organic phase and containing a correspondingly substituted toluene, at least one metal bromide, and a base, and also the compounds obtained by this process.

Process for the production of substituted benzal and benzyl bromides

A process for the production of benzal bromides which contain an electrophilic substituent in the ortho- and/or para-position of the formula (Ia), or of mixtures thereof with the corresponding benzyl bromides of the formula (Ib), ##STR1## IN WHICH R represents an electrophilic substituent in the ortho- and/or para position, by treating correspondingly substituted toluenes with elementary bromine under irradiation with visible light in a two-phase system which consists of an aqueous and an organic phase, which process comprises carrying out the reaction in the presence of a base.

Process for the production of substituted toluene compounds

Process for the manufacture of aromatic, heteroaromatic or aliphatic compounds which contain at least one radical of the formula ##STR1## wherein R denotes a hydrogen atom or an alkyl, cycloalkyl or aralkyl radical, characterized in that an aromatic or heteroaromatic compound, which carries one or more electron-donating substituent with negative Brown substitution constants .delta..sub.p .sup.+ and without mobile hydrogen atoms, a .pi.-excess-hetero-aromatic compound or a CH-acid compound is reacted with a 2,2-dicyanoethylene of the formula ##STR2## wherein X is a halogen atom, preferably chlorine or bromine, and R has the abovementioned meaning, without the presence of Lewis acids, in an anhydrous, preferably organic, medium, with an acid-binding agent optionally being added as a further component.

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Birsfelden, Switzerland

Tibor Somlo