Abstract: Compounds of the formula ##STR1## wherein X denotes a chlorine or bromine atom, n denotes a number from zero to 4 and Y denotes an oxygen atom or a nitrogen atom, and A, if Y represents an oxygen atom, is the phenyl radical, which can be substituted by substituents from the group comprising halogen, C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -alkoxy, carbalkoxy with 1-4 carbon atoms in the alkyl radical, hydroxyl, carboxyl, CF.sub.3, nitro, phenoxy, phenoxy which is substituted by C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -alkoxy and/or halogen, phenylamino, phenylamino which is substituted in the phenyl radical by C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -alkoxy and/or halogen, phenylazo and phenylazo which is substituted by C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -akloxy and/or halogen, or is the pyridyl radical, which can be substituted by halogen and/or C.sub.1 -C.sub.

Abstract: Preparation of 3,4,9,10-perylenetetracarboxylic acid diimide by fusing naphthalene-1,8-dicarboxylic acid imide with potassium hydroxide and sodium acetate to give the alkali metal salt of the leuko compound of 3,4,9,10-perylenetetracarboxylic acid diimide, diluting the melt with water when the reaction has ended and oxidizing the leuko form to give the 3,4,9,10-perylenetetracarboxylic acid diimide, by a procedure which comprises(a) applying a vacuum of less than 100 mm Hg before the naphthalene-1,8-dicarboxylic acid imide is introduced into the potassium hydroxide/sodium acetate melt, heating the potassium hydroxide/sodium acetate mixture to 200.degree.-300.degree. C. and dehydrating it such that the melt is still stirrable at 200.degree.-220.degree. C., and then introducing the naphthalene-1,8-dicarboxylic acid imide or its sodium or potassium salt into the melt at 200.degree.-220.degree. C. under normal pressure and heating the mixture at 250.degree.-300.degree. C.

Abstract: Perylene-3,4,9,10-tetracarboxylic acid monoanhydride mono-sodium or mono-potassium salts are obtained from neutral salts of perylene-3,4,9,10-tetracarboxylic acid, if necessary in the presence of at least one molar equivalent of sodium or potassium ions, at 20.degree. to 100.degree. C. by adding three molar equivalents of a sufficiently strong acid. The products are dye precursors, especially for asymmetric N-substituted perylenetetracarboxylic acid diimide pigments.

Abstract: The invention relates to a process for the preparation of perylene-3,4,9,10-tetracarboxylic acid N,N'-dialkyldiimides by reacting perylene-3,4,9,10-tetracarboxylic acid dianhydride with an alkylamine in aqueous suspension at a low temperature, in the course of which the bis-(alkylammonium) salt of perylene-3,4,9,10-tetracarboxylic acid bis-N-alkylamide is formed. The latter is reacted with a metal salt to give the corresponding sparingly soluble metal salt, which is subjected to the cyclization reaction at an elevated temperature. The pigments prepared by the process according to the invention are distinguished by high purity and are suitable for pigmenting lacquers and plastic compositions.

Abstract: A perylene-3,4,9,10-tetracarboxylic acid dianhydride pigment, useful as a varnish pigment, made by adding an aqueous solution of an alkali metal salt of perylene-3,4,9,10-tetracarboxylic acid and a surfactant to an acid at a pH below 3, at 0.degree. C. to 90.degree. C., and then heating the suspension so obtained at 50.degree. C. to 150.degree. C.

Abstract: The invention provides a process for the preparation of 4,7-dichloro-3-hydroxy-thionaphthene by reaction of 2,5-dichlorophenyl-thioglycolic acid chloride in dichloromethane in the presence of Friedel-Crafts catalysts.

Abstract: Very pure, transparent pigments of high color strength, of the formula ##STR1## in which R is hydrogen or alkyl having 1 to 4 C atoms, X is chlorine and/or bromine and n is a number from 0 to 4 are obtained by converting the corresponding crude pigment to the sulfate, isolating the sulfate, liberating the pure product from the sulfate by hydrolysis, separating off the pure product and dry milling the anhydrous material, with or without additives and with or without subsequent solvent finishing. These pigments are suitable for coloring paints and plastic compositions, especially for pigmenting metallic paints.

Abstract: Thioindigo and its derivatives are obtained in high yield and excellent purity by oxidizing corresponding 3-hydroxy-thionaphthenes with peroxo-disulfate in an aqueous alkaline solution.

Abstract: Coarsely crystalline crude dioxazine pigments are subjected to dry milling while maintaining their crystallinity as far as possible until the desired degree of fineness is reached and then treated with a solvent.

Abstract: Thioindigo and its derivatives are obtained in high yield and excellent purity by oxidizing corresponding 3-hydroxythionaphthenes with peroxo-disulfate in an aqueous alkaline solution.

Abstract: This invention relates to a process for the preparation of a very pure copper phthalocyanine pigment of the .alpha.-modification which comprises dissolving crude copper phthalocyanine in a 80 to 86% sulfuric acid isolating the copper phthalocyanine sulfate formed, hydrolizing the sulfate and grinding the copper phthalocyanine thus obtained in an aqueous-organic medium.

Abstract: Unsubstituted linear trans-quinacridone of the gamma-crystal modification is obtained by cyclization of 2,5-dianilino-terephthalic acid with the 2.5 to 4-fold quantity of polyphosphoric acid or of an acidic polyphosphoric acid methyl ester, followed by hydrolysis of the condensation product in water, intensive grinding of the aqueous crude quinacridone in the presence of an alcohol or ketone and heating of the resulting product to 80.degree. to 200.degree. C.

Abstract: N,N'-dimethyl-perylene-3,4,9,10-tetracarboxylic acid diimide is obtained as a valuable pigment of a pure red shade, by reacting perylene-3,4,9,10-tetracarboxylic acid anhydride at low temperatures with a dilute aqueous solution of at least the four-fold molar amount of methylamine. The so-obtained bis-ammonium salt of the bis-N-methyl amide is then heated without isolation to effect ring closure while splitting off two mols of water and two mols of methyl amine. The product can be used without any finish operation or can be after-treated to yield a pigment of an exceptionally high transparency or of a good hiding power.

Abstract: 2,5-Diarylamino terephthalates are obtained in good yields and excellent purity when the aromatic nitro compound used for oxidizing the corresponding dihydro-2,5-diarylamino terephthalate contains the aromatic radical of said diarylamino groups, i.e. when the amine formed during the oxidation is that from which said diarylamino groups device. The products yield very pure quinacridone pigments and allow the synthesis of only one isomer of substituted quinacridones.

Abstract: When reacting a dyestuff having hydroxy, acyloxy, carboxy or carbalkoxy groups with a polyester derived from terephthalic and/or isophthalic acid and, per mol of dicarboxylic acid, about 0.75 to 1.5 mol of a low-molecular alkanetriol with primary alcohol groups (methylol groups) or, instead of said polyester, with the corresponding starting materials or precondensates, a polyester with chemically linked dyestuff units is obtained which is useful for dyeing plastics, especially polyolefins. The dyed plastic materials are heat resistant, even when containing fluorescent dyestuff units, transparent and uniformly dyed.

Abstract: Highly pure .alpha.-copper phthalocyanine is obtained when a product regenerated from .alpha.-copper phthalocyanine sulfate by hydrolysis with water is aftertreated in an aqueous medium containing a polar organic non-aromatic compound which is water-soluble or liquid. The aftertreated product has an especially high tinctorial strength, is very easily dispersible and has a very pure reddish-blue shade.

Abstract: A process for the preparation of highly pure organic pigments which comprises converting organic dyestuffs having various degrees of purity into dyestuff salts capable of being isolated by means of suitable acids which dissolve the impurities contained in the dyestuff, separating them from the acid, recovering the dyestuffs in pure form from the dyestuff salts by the action of water and subjecting the isolated dyestuff in aqueous organic or aqueous-organic medium to a mechanical fine dispersion. By this process the dyestuff formed by the decomposition of the dyestuff sulfate is obtained in highly pure form and can extremely well be brought into a finely dispersed form so that it can be brought into pigment form already by short-time grinding. During the preparation and isolation of the dyestuff sulfate the sulfuric acid is obtained in such a high concentration that it can be regenerated in an economical manner and any ecological charge is avoided.

Abstract: A process for the purification of optionally substituted crude phthalocyanines wherein a phthalocyanine is introduced into a 84 to 88 % sulfuric acid, the phthalocyanine sulfate formed is subjected to a crystal growth at 60 - 100.degree. C in an inert gas atmosphere, the phthalocyanine sulfate is isolated and the phthalocyanine is recovered by hydrolysis with water. By this process a phthalocyanine sulfate is formed in a coarse crystalline form which can easily be filtered and which furtheron can easily be processed to a valuable pigment of the .alpha.-modification.

Abstract: A continuous process for preparing copper phthalocyanines by caking a mixture of phthalodinitrile, and a copper salt which comprises carrying out the reaction in a continuously working, heatable, tubular vibration mill, which contains iron or steel bars in the grinding room.In comparison with the continuous processes hitherto known this process requires a considerably smaller amount of thermal energy from outside, since the amount of heat formed in the strongly exothermic condensation process is, to a considerable extent conducted away from the reaction zone, with the aid of heat-conducting grinding bars, and is used in order to heat up the freshly introduced starting product to room temperature.

Abstract: Polyhalo copper phthalocyanines are obtained by reacting a di- to tetrahalo phthalic acid or a derivative thereof, if necessary urea, a copper salt, a titanium tetrahalide and a compound capable of forming an addition compound with said titanium tetrahalide. The purification of the so-obtained products is much easier since lower amounts of titanium compounds can be used. The products are useful as pigments.