摘要:
Process for preparing haloaromatic amines by catalytic hydrogenation of the corresponding halonitroaromatic compounds, characterized in that iron-containing Raney nickel is used as catalyst, where the haloaromatic amines prepared can be used for the synthesis of photographic couplers which are useful in photographic emulsions or elements.
摘要:
m-Chlorotoluene is removed from chlorotoluene mixtures with a content of up to 10% by weight of m-chlorotoluene, with reference to the total amount of chlorotoluene in the mixture, by chlorinating a substantially toluene-free chlorotoluene mixture in the presence of a Friedel-Crafts catalyst and if appropriate a co-catalyst at from 0.degree. C. up to the boiling point of the mixture, until the content of m-chlorotoluene has decreased to a value of
摘要:
2-Chloro-4-methylphenol is prepared by reacting 4-methylphenol with a chlorinating agent in the presence of a catalyst system of one or more Lewis acids in a total amount of 0.1-10% by weight and one or more diaryl sulphides in a total amount of 0.1-10% by weight, all based on the amount of 4-methylphenol. The reaction temperature is 0.degree.-100.degree. C. The chlorinating agent is used in an amount of 0.5-1.5 mol per mole of 4-methylphenol. The reaction can be carried out until virtually complete consumption of the 4-methylphenol, high isomeric selectivity and high stage selectivity being observed.
摘要:
Benzothiazepinone derivatives can be prepared by alkaline hydrolysis of benzothiazoles to give o-amino-thiophenols, isolation thereof by acidification and further reaction with acrylic acids. In this connection, the acidification is carried out using a mineral acid, after which the o-amino-thiophenol is extracted using a water-insoluble solvent and is reacted in this extract with an acrylic acid.
摘要:
Aromatic hydrocarbons are chlorinated in the nucleus in the presence of Friedel-Crafts catalysts and in the presence of co-catalysts in the liquid phase by using thiazepines as co-catalysts.
摘要:
Alkyl-(3-chlorophenyl)-sulphones are particularly advantageously obtained by chlorination of alkylphenylsulphones if alkylphenylsulphones are chlorinated in molten form with elemental chlorine in the presence of iron(III) chloride and optionally iodine and/or sulphur.
摘要:
In a particularly advantageous process for producing 2-cyanoindan-1-ones from 2-halogenated indan-1-ones by reaction with a cyanide salt, the cyanide salt is dissolved in a dipolar aprotic solvent or in a water-miscible ether and 2-halogenated indan-1-one is metered into this solution.
摘要:
Halogenated aromatic carboxylic acids are decarboxylated by heating them in the presence of water at temperatures of 80.degree. to 180.degree. C. and in the presence of water and other acids at temperatures above 80.degree. C.
摘要:
Hydroxypivalic acid is obtained from aqueous solutions by removal of the water by azeotropic distillation and subsequent crystallization from a solvent mixture which is composed of a polar and a non-polar component. The distillation is carried out under reduced pressure and at a maximum bottom temperature of 90.degree. C., until a residual water content of at least 0.1% of the total weight of the resulting solution is achieved.
摘要:
A process for separating off poorly soluble by-products from reaction mixtures which are produced in the oxidation of p-cresol with oxygen or an oxygen-containing gas in methanol as solvent in the presence of alkali metal hydroxide and in the presence of metal compounds as catalyst, is characterized in that, after the oxidation, excess alkali is neutralized to the extent that a salt precipitate forms and this salt precipitate is separated off together with the poorly soluble by-products.