CS264930B1 - 2-aminophenol-4- (N, 4'-carboxyphenyl) sulfonamide; - Google Patents

Abstract

The solution falls into the field of organic dye chemistry. The aim of the solution is the compound 2-aminophenol-4-(N,4'-carboxyphenyl)sulfonamide and a method for its preparation. The method for preparing 2-aminophenol-4-(N,4'-carboxyphenyl)sulfonamide of formula I consists in reducing 2-nitrophenol-4-(N,4'-carboxyphenyl)sulfonamide in an aqueous medium with a mixture of iron and hydrochloric acid or a mixture of iron and ferrous salts of hydrochloric or sulfuric acid at a temperature of 90 to 100 °C.

Description

(57) The solution falls within the field of organic dye chemistry. The object of the invention is 2-aminophenol-4- (N, 4'-carboxyphenyl) sulfonamide and a process for its preparation. A process for preparing 2-aminophenol-4- (N, 4'-carboxyphenyl) sulfonamide of formula I

characterized in that the 2-nitrophenol-4- (N, 4'-carboxyphenyl) sulfonamide is reduced in an aqueous medium by a mixture of iron and hydrochloric acid or a mixture of iron and ferrous salts of hydrochloric or sulfuric acid at a temperature of 90 to 100 ° C.

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The invention relates to 2-aminophenol-4- (N, 4 ' -carboxyphenyl) sulfonamide and to a process for its preparation.

Metal-complex azo dyes are used for dyeing wool and polyamide, where 2-aminophenol-4-sulfonamide or 2-aminophenol-4'-N-methylsulfonamide is used as the active component.

The compound 2-aminophenol-4- (N, 4'-carboxyphenyl) sulfonylamide has now been prepared for similar use.

A process for preparing 2-aminophenol-4- (N, 4'-carboxyphenyl) sulfonamide of formula I

The process of claim 2, wherein the aqueous 2-nitrophenol-4- (N, 4'-carboxyphenyl) sulfone amide is reduced by a mixture of iron and hydrochloric acid or a mixture of iron and ferrous salts of hydrochloric or sulfuric acid at a temperature of 90 to 100 ° C.

The resulting amino compound suspension is separated from the reduction products (reducing sludge) by converting the amino compound into alkaline solution with sodium hydroxide and subsequent filtration.

The compound of formula I is precipitated from the solution by acidification with a suitable acid, e.g. hydrochloric acid.

The conversion process is not accompanied by chemical side reactions. After isolation, a practically pure compound of formula I is obtained with a melting point of 299 DEG -302 DEG C. in a yield of 85% of theory. Diazotization and subsequent coupling titration of this compound confirmed the presence of an aromatically bound amine and determined the relative molar mass of 308.

An embodiment of the invention is illustrated by the following example.

Example

40 g of iron filings are added to 60 ml of water while stirring, heated to 80 ° C and 4 ml of hydrochloric acid having a concentration of c (HCl) = 9 mol / l are slowly added. The reaction mixture is heated to 95 ° C and allowed to stir at this temperature for 30 minutes.

The temperature is then adjusted to 100 ° C and 33.8 g of 100% 2-nitro phenol-4- (N, 4'-carboxyphenyl) sulfonamide (0.1 mol) are slowly added over 4 hours. After dosing, the mixture was allowed to react for 3 hours at 100 ° C.

After the reduction is complete, the suspension is taken up in solution with sodium hydroxide c (NaOH) = 10 mol / l and possible dilution with water. After alkalization, the solution has a final pH of 11 to 12.5.

The solution is heated to 100 ° C, stirred briefly and the reducing sludges are separated by filtration. The filtrate is cooled to 10-20 ° C, acidified slowly with hydrochloric acid and the product isolated by filtration. The filter cake was washed with water until the acidic reaction of the filtrates was lost.

26.2 g of the product of formula I of m.p. Mp 299-302 ° C.

Claims (2)

SUBJECT OF THE INVENTION A 2-aminophenol-4- (N, 4'-carboxyphenyl) sulfonamide of Formula I COOH (I) 2. A process for the preparation of 2-aminophenol-4- (N, 4 ' -carboxyphenyl) sulfonamide of the formula I as claimed in claim 1, characterized in that 2-nitrophenol-4- (N, 4 ' -carboxyphenyl) sulfonamide is iron and hydrochloric acid or mixtures of iron and ferrous salts of hydrochloric or sulfuric acid at a temperature of 90 to 100 ° C.