Abstract: Process for retanning mineral-tanned leathers, characterised in that the retanning agents used are sulphonic acids and/or salts thereof of the general formula ##STR1## wherein R represents hydrogen, --CH.sub.3 or the radicals ##STR2## X represents hydrogen, an alkali metal ion, especially sodium, potassium or lithium ion, or an ammonium ion andn represents 1, 2, 3 or 4.

Abstract: In the production of chrome leather, a pretreatment of delimed and bated pelts with condensation products not having a tanning action leads to substrates which, without any problems, can be mechanically dewatered and shaved or split and shaved.The properties of the leathers produced therefrom by chrome tanning do not differ from those of leathers which have been conventionally chrome-tanned and shaved.

Abstract: Crome tanning of pickled animal hides with a tanning agent comprising a reaction product of a basic chromium (III) sulfate and aliphatic C.sub.4 -C.sub.6 dicarboxylic acids or their salts is improved by preparing the reaction product in an aqueous solution from basic chromium (III) sulfate and 0.2 to 0.8 mol of the aliphatic dicarboxylic acids per mol chromium oxide of the basic chromium sulfate with subsequent adjustment of the theoretical basicity to 0 to 50% with alkali metal hydroxide or carbonate, the reaction product being added to a hide pickling liquor in the form of an aqueous solution having a chromium oxide content of at least 5% or in powder form in a quantity of 0.9 to 1.5% chromium oxide, based on hide weight, with a liquor volume less than 100%, based on hide weight, the final pH value being above 4.0 and the final temperature above 40.degree. C.

Abstract: The present invention relates to a process for the retanning (afterchroming) of chrome leathers. It has been found very high chromium exhaustion of the liquor can be achieved if the leather is retanned with mixtures of,(a) chromium (III) salts,(b) from 1.0 to 2.5 mol (per mole of Cr.sub.2 O.sub.3 of the used chromium(III) salt) of aliphatic dicarboxylic acids having from 4 to 6 carbon atoms or aromatic dicarboxylic acids having from 8 to 12 carbon atoms and/or the salts thereof,(c) such a quantity of basifying agents, that a theoretical basicity of the used chromium(III) salt of from 80 to about 120% is established, and(d) from 150-250 g (per mol of Cr.sub.2 O.sub.3 of the used chromium(III) salt) of one or more synthetic tanning agents (syntans).

Abstract: Process for mass-dyeing of thermoplastics, characterized in that the dyestuffs used are of the formula ##STR1## in which X designates a radical ##STR2## R designates hydrogen or alkyl, R.sub.1 and R.sub.2 designate alkyl,R.sub.3 designates hydrogen, cyano, aroyl, alkoxycarbonyl, alkylcarbonyl or carbamoyl,R.sub.4 designates aryl,R.sub.5 designates alkyl, alkylcarbonyl, alkoxycarbonyl or aryl,R.sub.6 designates alkyl, aryl, aralkyl or aralkenyl, andY designates O or NR.sub.7, with R.sub.7 having the meaning hydrogen, alkyl, aralkyl or aryl, it being possible for the radicals which have been mentioned for R.sub.7 and R.sub.1 -R.sub.

Abstract: 1,4-Bis-(4-chloro-2-methoxystyryl)-benzene is highly suitable for whitening polymeric substances, in which use it is distinguished, for example, by a good yield and a pleasant shade.

Abstract: Compounds of the formula ##STR1## in which R.sup.1, R.sup.2 and R.sup.3 denote hydrogen, alkyl, alkoxy or halogen,A denotes aryl or a radical of the formula ##STR2## wherein R.sup.8 denotes aryl, alkyl, aralkyl, styryl or alkoxy,R.sup.9 denotes hydrogen, CN, COOR, CONRR' or R.sup.8 and X denotes N or C(R.sup.10),R.sup.4 and R.sup.10 denote hydrogen, alkyl or aryl,R.sup.5, R.sup.6 and R.sup.7 denote hydrogen, halogen or alkyl, inter alia,R denotes alkyl andR' denotes R or H,are valuable optical brighteners for polyesters, polyamides, cellulose esters and polyacrylonitrile.

Abstract: Compounds of the formula ##STR1## in which R.sub.1 denotes aryl, alkyl, aralkyl, styryl or alkoxy,R.sub.2 denotes hydrogen, cyano, carboxyl or alkoxycarbonyl, inter alia,R.sub.3, R.sub.4, R.sub.6 and R.sub.7 denote hydrogen, alkyl, alkoxy or halogen,R.sub.5 denotes hydrogen, alkyl or aryl,R.sub.8 and R.sub.9 denote hydrogen, cycloalkyl, alkenyl, alkyl or aralkyl,A.sup..crclbar. denotes an anion,w denotes the valency of the anion A andn denotes 0 or 1,are outstandingly suitable for optically brightening synthetic fibre materials, in particular acrylic fibres.The new brighteners are prepared and used in accordance with methods which are in themselves known.

Abstract: Optical brighteners of the formula ##STR1## wherein the radicals R.sub.1 to R.sub.9 are substituents customary in brightener chemistry,A.sup..crclbar. denotes a colorless anion,w denotes the valency of the anion A andn denotes 0 or 1,are obtained in a simple manner when a compound of the formula ##STR2## is heated to 110.degree.-200.degree. C. in an inert solvent, without the addition of a catalyst.

Abstract: Compounds of the formula ##STR1## wherein R.sup.1, R.sub.2 and R.sub.3 denote hydrogen, chlorine or methyl,R.sup.4 denotes C.sub.1 -C.sub.4 -alkyl which is optionally substituted by phenyl, hydroxyl or C.sub.1 -C.sub.4 -alkoxy andX.sup..crclbar. denotes a colorless anion.A process for their preparation and processes for brightening polyacrylonitrile and wool using compounds of the formula (I).