DD150622A1 - METHOD FOR PRODUCING OXAZINE DYES - Google Patents

Abstract

The invention relates to a novel process for the preparation of dyes of the formula I in which R is H, Cl, NO 2, COOH or SO 3 H. They are obtained according erfindaesz by optionally substituted 2-Aminophenolsulfonsaeuren with 1,2-dihalo-3,5-dinitrobenzenes or suitable derivatives of 2,4-dinitro-6-halophenol at temperatures of 60 to 120 degrees C and a pH greater be implemented as 7.

Description

VEB CHEMIEKOMBIQTAT BITIERFELD

Bitterfeld, -12-5-1980 2077

Process for the preparation of oxazine dyes

Field of application of the invention

The invention relates to a process for the preparation of water-soluble dyes of the oxazine series, which in the acid form of the formula

correspond. Herein R = H, Cl, NOp, COOH or SOoH. Dyes of this type have an excellent through-dyeing ability for leather.

- 2 - 221063 2077

Characteristic of the known technical solutions

Dyes of the formula I and a process for their preparation are known from DE-PS 679 984 * Disadvantages of the process described therein are the physicochemical properties of the intermediates trinitroanisole or picric acid required for the synthesis as starting material for 2,4, 6-trinitrochlorobenzene, which are known explosives. Picric acid is also produced by the dye synthesis itself by an unavoidable side reaction. It can not be separated from the dye by its high solubility and separates on evaporation of the reaction mixture in the form of fist-sized nests, which represent an extraordinary source of danger already during drying, but especially in the subsequent mechanical comminution.

In order to avoid the dangers arising after the synthesis, a process for the preparation of a stable liquid preparation of the dye of the formula I where R "= COOH has already been proposed (WP C 09 B / 216 697). However, this method does not eliminate the hazards associated with the use and production of trinitroanisole for dye synthesis.

Object of the invention

The object of the invention is a process for the preparation of dyes of the formula I, which avoids both the use of trinitroanisole or picric acid for the synthesis, as well as the formation of picric acid during the synthesis and thus completely excludes the dangers thereby given.

2 2 10 6ο 2077

^ the essence of the invention

Starting from the object of the invention, while avoiding the use of picric acid or its derivatives, a new synthesis of dyes of the formula I was found. The condition had to be satisfied that the new synthesis requires only those intermediates whose explosive character is low compared to picric acid or trinitroanisole.

In pursuit of the object of the invention, it has been found that oxazine dyes of the formula I can be obtained by reacting optionally substituted 2-aminophenolsulphonic acids with either 1,2-dichloro- or 1-bromo-2-chloro-3, 5-dinitr, above or suitable reactive derivative of 2,4-dinitro-6-chloro- or -6-bromophenol obtained v / earth.

Such reactive derivatives are e.g. lower alkyl ethers, such as methyl or ethyl ether, carboxyalkyl ethers or esters of arylsulfonic acids.

The process of the invention is based on a hitherto unknown reaction in which dinitrooxazines are formed from 1T- (2,4-dinitro-6-halophenyl) -2- ^f- aminophenols with the elimination of hydrogen halide. The new synthesis according to the invention can be carried out favorably in a temperature range from 60 to 120 ^° C., the temperature range between 80 and 100 ^° C. being preferred. For the formation of the dyes of the formula I, a pH of more than 7, preferably even more than 9 proves to be favorable.

The expected prior art formation of halogeno-nitro-oxazines takes place only to a very limited extent.

The following examples serve to illustrate the invention without, however, limiting it thereto.

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Application Examples Example 1

Dissolve 23 »2 parts of 2-hydroxy-3-amino-5-sulfobenzoic acid in 90 parts of water by adding 14.0 parts of sodium carbonate. 24.0 parts of 1,2-dichloro-3 »5-dinitrobenzene are introduced into the solution. The suspension is heated to 90 ° C. with stirring and the pH is kept at 9 by addition of sodium hydroxide solution for 15 hours. Thereafter, the formation of the oxazine dye is completed. The reaction mixture can be evaporated to dryness to recover the solid.

This gives about .60 parts of a brown powder which has an equally good through-dyeing power for leather, such as the dye obtainable from trinitroanisole and 2-hydroxy-3-amino-5-sulfobenzoic acid according to DE-PS 679 984.

Example 2 to 5

If, instead of the 1,2-dichloro-3 »5-dinitrobenzene in Example 1, the following compounds in the amounts indicated

28.1 parts of 1-bromo-2-chloro-3,5-dinitrobenzene 27.7 parts of 1-methoxy-2-bromo-4,6-dinitrobenzene

23.3 parts of 1-methoxy-2-chloro-4,6-dinitrobenzene

29.4 parts of 1-benzenesulfonyloxy-2-chloro

4,6-dinitrobenzene

and proceeds in the other of Example 1, we obtain in all cases the "dyes as brown powder.

In all examples listed, the dyes obtained with the dyes, according to DE-PS 679 984 are virtually identical. In contrast to the dyes according to DE-PS 679 984 but contain the dyes obtained according to Example 1 to 5 barely detectable amounts of nitrite and no picric acid.

Claims (2)

2 2 1063 2077 claim for invention 1 · Process for the preparation of oxazine dyes, which are in the acid form of formula -NO, (D in which R β denotes H, Cl, HO ₂ , COOH or SOJH, characterized in that optionally substituted 2-aminophenolsulphonic acids are reacted with 1,2-dihalogeno-3-dinitrobenzenes or suitable derivatives of 2,4-dinitro-6-one halogenphenols be implemented. - 6 - 2 2 10 6 3 ²⁰⁷⁷ 2 »Verfaliren according to item 1, characterized in that the reaction at temperatures of 60 to 120 ⁰ C, preferably 80 to 100 ⁰ C, and at a pH greater than 7, preferably greater than 9, takes place.