Abstract: 2,3,4,5-tetrafluorobenzene derivatives can be obtained in a particularly advantageous manner by reacting the corresponding chlorobenzene or (chloro, fluoro)-benzene derivatives with a fluorinating agent in the presence of a solvent and a catalyst at elevated temperature, which comprises carrying out the reaction initially under temperature and pressure conditions such that the respective 2,3,4,5-tetrafluoro-benzene derivative continuously distills off through a column, and subsequently setting temperature and pressure conditions such that residual fractions of the 2,3,4,5-tetrafluorobenzene derivative distill off with the corresponding 2,3,4-trifluoro-5-chloro compound.

Abstract: Liquid polyamine crosslinking agent formulations based on trimerized toluylene 2,4- and/or 2,6-diisocyanate, with formation of an isocyanurate structure and hydrolysis of the isocyanate groups to amine groups, are described. The novel crosslinking agent formulations have a content of 40 to 80% of the total weight of the solids content of the crosslinking agent formulation of 1,3,5-tris-(3-amino-4-methyl-phenyl,2-methyl-3-aminophenyl) isocyanurate (I) which is not further condensed, and a content of not more than 1.0% of the total weight of the crosslinking agent formulations of toluylene-2,4- and/or -2,6-diamine (III). For the preparation, toluylene diisocyanate is trimerized, to form the isocyanurate structure, until 10 to 25% of the NCO groups have been reacted.

Abstract: 4-Fluorothiophenol is obtained in outstanding purifies and yields if 4-fluorobenzenesulphonyl chloride is reacted with sodium hydrogen sulphite solution to give a solution of sodium 4-fluorobenzenesulphinate, this solution is reduced with sulphur dioxide to give 4,4'-difluorodiphenyl disulphide and finally this is reacted with sodium borohydride in a water-miscible inert organic solvent to give 4-fluorothiophenol (sodium salt). Free 4-fluorothiophenol can be isolated from the sodium salt solution by acidification.

Abstract: In the preparation of 3,5-dichloro-.alpha.-methylstyrene by isopropylation of an m/p-dichlorobenzene mixture, isomerization of the resulting alkylation mixture, subsequent side chain bromination of the alkylation mixture and dehydrobromination of the resulting bromination mixture, the improvement which comprises reacting an excess of an m/p-dichlorobenzene mixture which contains at least 50% by weight of m-dichlorobenzene with isopropyl halide, isomerizing the resulting alkylation mixture under pressure in the presence of aluminum chloride until thermodynamic equilibrium has been attained, separating off the isomerized alkylation mixture from the unreacted m/p-dichlorobenzene mixture, and recycling the unreacted mixture for further reaction.

Abstract: Substituted benzaldehydes are prepared by reaction of the substituted benzenes from which they are derived with carbon monoxide and hydrogen chloride in the presence of metal halides, the process being performed in the presence of 0.5 to 10 mols of hydrogen chloride per mol of metal halide at a partial pressure of carbon monoxide from 1 to 100 bars and a temperature from -20.degree. C. to +100.degree. C. and, if desired, in the presence of an inert diluent. The substituted benzaldehyde which contains, as a substituent, alkyl with at least 2 carbon atoms, cycloalkyl or optionally substituted benzyl, is prepared by reacting the appropriately substituted benzene with the additional presence of a benzene which does not contain the substituents mentioned, but which is identical in respect of further substituents which are optionally present with the benzene from which it is derived.

Abstract: The invention relates to a process for the preparation of polyarylene sulphides in alkylated polyureas at a temperature of 250.degree. to 290.degree. C. under a pressure from 4 to 50 bars.

Abstract: High molecular weight p-polyarylensulfides having a high melt viscosity, capable of being processed thermoplastically, and have good mechanical properties are produced by reacting components (a), (b), and (c) in a polar solvent with a molar ratio of (a):(c) in the range of 0.85:1 to 1.15:1 and a molar ratio of (c): solvent in the range of 1:2 to 1:15, for a time of up to 10 hours at a temperature of from 160.degree. C. to 300.degree. C.

Abstract: The subject matter are triazolyl-stilbenes of the formula ##STR1## wherein R.sub.1 represents an optionally substituted styryl, biphenylyl or naphthyl radical, R.sub.2 represents hydrogen, halogen, or an alkyl or phenyl radical and R.sub.3 represents nitrile, carboxyl or carboxylic acid ester, as well as their preparation and their use as optical brighteners.

Abstract: Process for the preparation of bis-triazolylstilbene compounds which, in the form of the free acid, correspond to the formula ##STR1## wherein the phenyl radicals A can be substituted by halogen, C.sub.1 -C.sub.4 -alkyl or C.sub.1 -C.sub.4 -alkoxy, from bis-hydroxyiminohydrazonostilbene compounds of the formula ##STR2## characterized in that the bis-hyroxyiminohydrazonostilbene compounds are reacted with anhydrides of lower carboxylic acids in the presence of urea and polar solvents at temperatures from 10.degree. to 60.degree. C.

Abstract: Compounds of the formula ##SPC1##Wherein R.sub.1 and R.sub.2 denote hydrogen, halogen, nitrile, alkoxy, alkyl, aryl, cycloalkyl, aralkyl, carboxyl or carboxylic acid ester groups are suitable for the optical brightening of synthetic organic high molecular materials.

Abstract: 3-Aryl-7-pyrazolyl-coumarin compounds of the formula ##SPC1##In which R stands for hydrogen, halogen, alkyl or alkoxy radicals, n represents the numbers 1-3, R.sub.1 and R.sub.2 represent, hydrogen or alkyl or phenyl radical, R.sub.1 and R.sub.2 may also form, together with the two carbon atoms of the pyrazole ring, a non-aromatic carbocyclic, 5- or 6-membered ring system, radical as well as their production and use as brightening agents.