DE1544559C - Process for the production of azo dyes - Google Patents

Description

In the German patents 636 358, 694 965, 1058 174, 1126 541 and 1126549 are processes described for the production of nouns dyes, which consist in the fact that you add 2 moles of nitrate dye, generally nitromonoazo dyes, linked reductively in a caustic alkaline medium, whereby In the exemplary embodiments, mainly grape sugar is used as a reducing agent. at When two nitro groups are linked, primarily azo and / or azoxy groups are formed. The use of glucose as the main reducing agent for this reaction has its sake The reason is that the majority of the compounds having a reducing effect in the alkaline range do not is useful because these either predominantly reduce the nitro groups to amino groups and therefore cause no linkage of two nitro-containing molecules or the nitroazo dye reductively split and thus destroy.

In the German patents 636 358 and 694 965, in addition to grape sugar, arsenic is also used Acid, formaldehyde and tin chloride have been cited as reducing agents. The range of applications of Tin chloride is only slight, so that it has not been used in practice. The disadvantage of using it of arsenic acid, in view of its toxicity, lies in handling and in the effluent broths On the hand. Formaldehyde proves to be unsuitable because of disruptive side reactions.

It has now surprisingly been found that hydrazine is excellent and generally useful Reducing agent in the alkaline range for linking nitrazo compounds under Formation of azo or azoxy groups is suitable and can completely replace grape sugar. The invention therefore relates to a process for the preparation of azo dyes in which 2 moles of the same or different Nitrazo compounds with hydrazine or its monoacyl or monoaryl derivatives in alkaline Medium are linked to one another with the formation of an azo or azoxy group. The method is particularly suitable for linking metal-containing or metallizable nitromonoazo compounds or nitrodisazo compounds, wherein in the case of using metallizable nitromonoazo compounds or nitrodisazo compounds this optionally then in substance. or be metallized on the fiber. The advantage compared to the use of grape sugar is that one means of reductive linkage Hydrazine can keep the drain broths free of additional contaminants because it is made up of hydrazine forms nitrogen in the course of the reduction process, which escapes as a gas.

In addition to the preferred hydrazine or hydrazine hydrate, with equally good or similar result also its monoacyl or monoaryl derivatives, such as semicarbazide, thiosscmicarbazide, Benzoylhydrazine or the sulfo- or carboxyphenylhydrazines provided with water-solubilizing groups can be used. The advantage of using the hydrazine derivatives over grape sugar lies in the independence from natural products.

To carry out the reduction, go to the

general like that before. that an aqueous solution or Ansclilämmung the Nitrazoverbindiing (s) on ■ increased temperatures, preferably heated between 50 to 100 ° C, adding alkali and the appropriate. Amount of aqueous hydrazine solution z. B. is added dropwise within 10 to 30 minutes. Should be when adding If the alkali does not dissolve the dye before the start of the reduction, the reduction is successful also with the undissolved alkaline dye suspension.

The reduction itself is generally in 10 after the dropwise addition of the hydrazine solution

ίο finished within 30 minutes. Your progression and yours Termination can be determined either by paper chromatography or empirically.

The choice of the optimal reduction conditions. depends on the type of Nitrazo compounds to be used turned off and can be easily determined by preliminary tests. Is the nitroazo dye to be reduced as a copper complex, it is advisable to avoid an excess of reducing agents, to avoid undesirable reductions in divalent copper.

Would be that hydrazine and its derivatives in the absence of catalysts in place of glucose ideal for linking nitrogrup- f penhaltiger azo dyes to form azo or Azoxygruppen use was not foreseeable and is particularly surprising in view of the types of A Fürst et al. in "Hydrazine as a Reducing Agent for Organic Compounds", Chem. Rev. 65 [1965], p. 52, bottom right.

In the following examples, the temperature data are degrees Celsius.

example 1

63 parts by weight of the copper-plated monoazo dye from diazotized 5-nitro-2-amino-1-oxybenzene and 2- (3'-sulfophenylamino) -8-oxynaphthalene-6-sulfonic acid in the form of the disodium salt are in 700 parts by weight of 90 "water with 75 parts by weight Sodium hydroxide solution (38 "Be) added. 200 parts by weight of a 4% hydrazine hydrate solution are now allowed to run in over a period of 30 minutes. After another 15 minutes salted and alkaline medium in the weakly r is isolated. As a free acid, the dye ν obtained corresponds to the formula

O Cu

-N = N

-SO ₁ H

and / or -N = N-

■ I

(O)

it dyes cotton in lightfast gray to blue-gray Tones.

Example 2

58 Ciewiclit parts of the dye from diazotized 5-nitro-2-ainino-1-methoxybenzene and 2- (3'-sulfopheiiylamino) -H -oxynaphlhalin -6-silfonsäure (dinalriumsal /) are in 1600 (parts by weight of water at ¹ JO with 75 ( iewiditteileeii sodium hydroxide solution (38 "Be) added. Nlti 11 läl.li one 55 μ I-SullOpheiiyl-hyclraziii,

X = -N = N-

which was dissolved in 200 parts by weight of water, run in within 20 minutes. After another 15 minutes is salted out and isolated at about 70 °. The in a known manner in the boiling heat in aqueous, ammoniacal solution of coppered dye corresponds to the formula as a free acid

HN

SO ₁ H

X = -N = N- and / or -N = N-

(Q)

he dyes cotton in lightfast gray to blue water at 50 ° with 90 parts by weight of sodium hydroxide solution

gray tones.

Example 3

44 parts by weight of the azo dye from 1-oxy-2-diazo-6-nitronaphthalene-4-sulfonic acid and / i-naphthol (sodium salt) are in 2000 parts by weight (38 ° Be) offset. 220 parts by weight of a 4% strength are then left in the course of about 30 minutes Run in hydrazine hydrate solution, salt out after a further 45 minutes and isolate when it is weakly alkaline Reaction. The dyestuff obtained corresponds to the formula as a free acid

OH

HO

and or

-N = N

' Ϊ (O)

it dyes cotton in full blue tones, the fastness of which on aftertreatment with copper salts be improved.

Example 4

54 parts by weight of the azo dye from diazotized 5-nitro-2-amino-l-methoxybenzene and 2- (4'-carboxyphciijlamino) - 8 - oxynaphthalene - 6 - sulfonic acid (disodium salt) are dissolved in 1700 parts by weight of water 75 parts by weight of sodium hydroxide solution (38 ° Be) are added at 90 °. Then leave within about 30 minutes to run 200 parts by weight of a 4% hydrazine hydrate solution, salts after a further 10 minutes and isolated at about 80 °. In a known manner in aqueous, ammoniacal solution at the boiling point In the form of the free acid, copper-plated dye corresponds to the formula

HOOC - <f> -NH

X = -N = N-

- X

and / or —N = N -

he dyes cotton in lightfast blue-gray tones.

. ic

U c ι s ρ ι u I Λ _{() S}

• 57 (iewichlsleile of the disazo dye, which by acidic coupling of 2-carboxy-l-clisa / o-ben / ol 2-Λιηϊηο - 5-oxynaphthalene - 7-sulfonic acid and then alkaline coupling of 5-nitro-2-dia / o-l-niethoxybenzene on this monoazo dye (sodium salt) are obtained in 4000 parts by weight 75 parts by weight of sodium hydroxide solution (38 Bc) are added to water at 50. Then one lets 220 parts of your choice within 30 minutes

Run in 4% hydrazine hydrate solution, add salt a further J 5 minutes and isolated in a weakly alkaline medium. The dye obtained corresponds to as a free acid of the formula

OH

CH, O

NH

it dyes cotton in blue tones and, after copying the fiber, gives washable dyeings.

B e i s ρ i e 1 6

58 parts by weight of the azo dye from diazotized 5-nitro-2-amino-1-methoxybenzene and 2- (3'-sulfophenylamino) - 8 - oxynaphthalene - 6 - sulfonic acid (disodium salts) are dissolved in 1600 parts by weight of water 75 parts by weight of sodium hydroxide solution (38 ° Be) are added at 90 °. A solution of 22 parts by weight is then left Semicarbazide dissolved in 100 parts by weight of water within 20 minutes add dropwise, salt out after a further 10 minutes and isolate at about 70 °. The known in the Dye, which is copper-plated in an aqueous ammoniacal solution at boiling heat, dyes cotton in lightfast blue-gray tones.

Example 7

35

'74 parts by weight of that from diazotized 2-amino-6-nitronaphthalene-4,8-disulfonic acid and 2-oxynaphthalene-3,6-disulfonic acid prepared and subsequently with copper sulfate and hydrogen peroxide in a weakly acidic medium of coppered dye (Tetrasodium salt) are in 1000 parts by weight of water at 60 ° with 90 parts by weight of sodium hydroxide solution (38 ° Be) offset. 220 parts by weight of a 4% hydrazine hydrate solution are then left in about 30 minutes run in, salt out and isolate after a further 15 minutes. The dye obtained corresponds to as a free acid of the formula

"HO ₃ SO

and or

X = -N = N-

-N = N- I
(O)

55

60 it dyes cotton in greenish blue, lightfast shades.

Example 8

23 parts by weight of the azo dye from diazotized 5-nitro-2-amino-1-methoxybenzene and 2-acetylamino-8-oxynaphthalene-6-sulfonic acid (Na salt) and parts by weight of the azo dye from diazotized 5-nitro-2-amino-1-methoxybenzene and 2-amino - Oxynaphthalene - 3,6 - disulfonic acid (disodium salt) are mixed together in 1600 parts by weight of water mixed and at 90 ° with 75 parts by weight of sodium hydroxide solution (38 ° Be) offset. Thereafter, 200 parts by weight of a 4% strength are allowed within about 30 minutes Run in hydrazine hydrate solution, salt out after a further minutes and isolate when it is weakly alkaline Reaction. The coppered in a known manner in aqueous, ammoniacal solution at the boiling point Dye dyes cotton in lightfast blue-gray tones.

Claims (3)

Patent claims: 1. Process for the preparation of azo dyes, characterized in that 2 mol identical or different nitroazo compounds with hydrazine or its monoacyl or monoaryl derivatives in an alkaline medium with the formation of an azo or azoxy group with one another connected. 2. The method according to claim 1, characterized in that there are 2 moles of the same or different Nitromonoazo or nitrodisazo compounds in an alkaline aqueous medium at temperatures from 50 to 100 ° C with hydrazine under training reductively linked to an azo or azoxy group. 3. Process according to Claims 1 and 2, characterized in that metal-containing Nitromonoazo or nitrodisazo compounds or metallizable nitromonoazo or nitrodisazo compounds uses and in the case of using metallizable nitromonoazo- or Nitrodisazo compounds, if appropriate, these subsequently metallized in bulk or on the fiber.