Abstract: The invention relates to a process for the preparation of 3-hydroxy-N-benzimidazolon-5-yl-2-naphthamide, which comprises reacting 5-aminobenzimidazolone and sodium carbonate in N-methylpyrrolidone with a solution of 3-hydroxy-2-naphthoyl chloride in xylene or toluene, filtering, washing with xylene or toluene, introducing the filter cake into water to which sodium carbonate has been added and steam-distilling, filtering off the residue with suction, washing and drying.

Abstract: The invention relates to a process for purification of 2-hydroxynaphthalene-6-carboxylic acid by recrystallization. In this process, the crude acid is recrystallized from water-miscible linear or cyclic aliphatic ethers, aliphatic polyethers or aliphatic hydroxy ethers or from at least 10% strength by weight aqueous solutions of these ethers. Recrystallization from a 35-90% strength by weight aqueous solutions of 1,4-dioxane is particularly preferred.

Abstract: 2-Hydroxydibenzofuran-3-carboxylic acid and its alkali metal salts are prepared by reacting an alkali metal salt of 2-hydroxydibenzofuran with carbon dioxide, where appropriate under pressure, at a temperature above 120.degree. C. in an aliphatic alcohol of 4 to 8 carbon atoms.

Abstract: Chlorozincate salts of benzothiazonium azo compounds are prepared by reacting benzothiazolium azo compounds with an dialkylsulfate having from 1 to 4 carbon atoms in the alkyl radicals, which process comprises carrying out the reaction in an aqueous medium at a temperature of from 10.degree. to 80.degree. C. in the presence of an acid acceptor and the alkylation with the use of from 1.8 to 2.5 mols of the dialkylsulfate, calculated on the starting azo dyestuff, at a pH not exceeding 7. The prepared benzothiazolium azo compound is precipitated as chlorozincate salt, especially with the use of an alkali metal chloride. According to this process, the chlorozincate salts are obtained in higher purity. A perceptible decomposition of the benzothiazolium azo compound does not occur. Chemicals, for example the alkylation agent and acid-binding agents need be used in a small quantity.

Abstract: 6-Hydroxy-2-naphthoic acid can be selectively acetylated to 6-acetoxy-2-naphthoic acid, in particular in the presence of admixtures of isomeric hydroxy-naphthoic acids, and thus be separated from those isomeric admixtures. The acetylation is affected in aqueous alkaline solution by reaction with acetic anhydride. By hydrolysis of the 6-acetoxy-2-naphthoic acid, a pure 6-hydroxy-2-naphthoic acid is obtained.

Abstract: Zinc chloride complex compounds to which the structure of the general formula (1) ##STR1## can be assigned, in which the individual radicals in the formula have the following meanings: Rhu 1 is a hydrogen atom or an optionally substituted lower alkyl group; R.sup.2 is a hydrogen atom, an optionally substituted lower alkyl group or an optionally substituted phenyl radical; R.sup.3 is a hydrogen atom or an optionally substituted lower alkyl group; R.sup.4 is a hydrogen atom, an optionally substituted lower alkyl group or an optionally substituted phenyl radical; R.sup.5 is a hydrogen atom or a halogen atom or a lower alkyl group or a lower alkoxy group, or R.sup.1 and R.sup.5 together form the o-phenylene radical; R.sup.

Abstract: Chlorozincate salts of thiazolium azo compounds are prepared by reacting thiazolium azo compounds with an dialkylsulfate having from 1 to 4 carbon atoms in the alkyl radicals, which process comprises carrying out the reaction in an aqueous medium at a temperature of from about 10.degree. to 50.degree. C. in the presence of a zinc compound capable of binding acid, and with the use of from 1.8 to 2.5 mols of the dialkylsulfate, calculated on the starting azo dyestuff, at a pH not exceeding 8, preferably at 3-7. The prepared thiazolium azo compound is precipitated as chlorozincate salt, especially by means of an alkali metal chloride. According to this process, the chlorozincate salts are obtained in higher purity. A perceptible decomposition of the thiazolium azo compound does not occur. Chemicals, for example the alkylation agent and acid-binding agents need be used in a small quantity.