GB2032943A

GB2032943A - Diazo Pigments

Info

Publication number: GB2032943A
Application number: GB7932858A
Authority: GB
Original assignee: BASF Farben und Fasern AG
Current assignee: BASF Farben und Fasern AG
Priority date: 1978-09-23
Filing date: 1979-09-21
Publication date: 1980-05-14
Also published as: DE2841532C2; DE2841532A1; CH644884A5; GB2032943B

Abstract

A diazo pigment dye having the formula <IMAGE> wherein D is the residue of an aromatic diazo component without water-solubilizing groups. The dyes possess good tinctorial and advantageous environmental properties. Methods for preparing the dyes are disclosed.

Description

SPECIFICATION Disazo Pigments Background of the Invention 1. Field of the Invention This invention relates to diazo pigments and particularly to diazo pigments derived from novel coupling agents.

2. Description of the Prior Art Diazo coloring agents, as a class, are well known and desirable because of their brilliant shades and good tinctorial properties. The diazo moieties of these pigments are usually prepared with coupling agents. However, one of the problems observed with such pigments is that they often require the presence of solubilizing agents which represent environmental pollutants.

Summary of the Invention We have discovered new diazo pigments which provide both excellent properties as pigments and also avoid the environmental problems resulting from the use of certain stabilizers.

More particularly, the diazo pigment dyes of the present invention have the formula

in which D represents the residue of an aromatic diazo component without water-solubilizing groups.

Pigment dyes of formula I are obtained by coupling diazotized amines which contain the D residue, with 6,8-diacetoacelainino-2,4-dioxotetrahydrnquinazoline (formula II).

The new diazo pigment dyes do not only represent an interesting enrichment to the range of pigment dyes available, but they also are distinguished by an environment-compatible method of manufacture because, as a result of the relatively good alkali solubility of the coupling components, the use of effluent contaminating solubilizers is omitted. On the basis of these advantageous properties, these diazo pigment dyes may be used in all areas of application of the pigment industry. They are, for example, well suited for the coloring of plastics, especially of PVC, as well as for the preparation of paints and printing inks.

Coupling component II is prepared by reacting 6,8-diamino-2,4-dioxotetrahydroquinazoline (Beilstein 25 1 699) with diketene.

Description of the Preferred Embodiment The coupling normally is carried out in such a manner that an acidic solution of the diazonium salt is added dropwise to an acetic acid suspension of the coupling component with a pH of ca. 5, with a final pH of ca. 4 being obtained. This step may optionally be carried out in the presence of a wetting agent.

The suspension of the coupling component is obtained by adding the coupling component, dissolved in alkali, dropwise into aqueous acetic acid at OOC. If a wetting agent is added, it is preferably added to the alkaline solution of 6,8-diacetoacetylamino-2,4-dioxotetrahydroquinazoline.

In another feasible coupling reaction, the coupling component dissolved in alkali, is added dropwise to a solution of diazonium salt, which has been buffered to a pH of 3 to 4. A final pH of 6 to 7 is obtained.

As wetting agents, cationic substances, such as, for example, fatty amines and their salts, nonionic products, such as, for example, sorbitan esters of fatty acids, or anionic wetting agents, such as, for example, aryl-alkyl sulfonates, may be used. Polyoxyethylated fatty amines may also be employed with success.

As diazo components, aromatic amines without water-solubilizing groups, which are conventionally used for the manufacture of pigments are employed. Examples of such amines are the anilines, substituted with chloro, nitro, alkyl or alkoxy groups or by carbonamido groups.

The pigments of formula (I) do not always exist in the physical form which is optimum for their intended application. They may, however, be converted into the desired form by known methods, such as, for example, salt grinding or heating in a solvent.

Obviously, for the preparation of the diazo pigment dye of formula (I), it is also possible to use an acetoacetate pigment which is obtained by coupling an acetoacetate with a diazotized amine, which contains the D residue, and condensing with 6,8-diamino-2,4-dioxotetrahydroquinazoline in a solvent.

The following examples illustrate the present invention: Example 1 Preparation of the Coupling Component: 6,8-diamino-2,4-dioxotetrahydroquinazoline (115.32 g), dissolved with heating in Nmethylpyrrolidone, is mixed with 151.34 g of diketene. In order to complete the reaction, stirring is continued at a higher temperature. The clarified and cooled reaction solution is added to 6,000 g of water with stirring in order to precipitate the product. The suspension is filtered with suction, washed and dried.

Example 2 Coupling of diazotized 2,4-dichloroaniline with 6,8-diacetoacetyla mino-2,4- dioxotetrahydroquinazoline: 2,4-dichloroaniline (32.4 g, 0.2 moles) is converted into a paste with 500 g of water and 82.95 g of concentrated hydrochloric acid, heated, cooled to OOC and diazotized with 14.0 g of dissolved sodium nitrite, stirred for an additional time and filtered with suction. 6,8-diacetoacetylamino-2,4- dioxotetrahydroquinazoline (36.8 g, 0.102 moles) are dissolved in 750 g of water with 31.2 g of sodium hydroxide solution. The coupling component is reprecipitated by being added dropwise to a mixture of 250 g of water/ice and 101.21 g of 60% acetic acid. To this suspension, the diazo solution is added dropwise.Stirring is continued for some time in order to complete the coupling reaction. The pigment suspension is filtered with suction and washed until it is neutral. The filter cake is dried and the crude product obtained is subjected to a solvent finishing in dimethyl sulfoxide.

Example 3 The procedure is identical with that in Example 2 with the exception, however, that, instead of 2,4-dichloroaniline, the following diazo components are used in equimojar amounts: Diazo Component: Shade: 0.20 moles, 32. 4 g of 2,5-dichloro- yellow with greenish tint aniline 0.20 moles, 39.2 g of 2,4,5-tri- yellow chloroaniline 0.20 moles, 28.3 g of 2-amino-4- yellow with greenish tint chlorotoluene 0.20 moles, 28.3 g of 2-amino-5- yellow with reddish tint chlorotoluene 0.20 moles, 28.3 g of 2-amino-6- yellow with greenish tint chlorotoluene 0.20 moles, 30.42 g of 2-amino-4- yellow with greenish tint nitroluene 0.20 moles, 30.8 g of 2-amino-5- yellow with reddish tint nitrotoluene 0.20 moles, 30.44 g of 3-nitro-4- yellow with reddish tint aminotoluene 0.20 moles, 33.64 g of 2-methoxy-4- reddish yellow nitroaniline Diazo Component: Shade: 0.20 moles, 48.46 g of 3-amino4- yellow with greenish tint methoxy benzanalide 0.20 moles, 31.52 g of 4-chloro-2- yellow aminoanisole 0.20 moles, 31.7 g of 2-chloro-4- yellow with reddish tint aminoanisole 0.20 moles, 30.64 g of 2,4-dimethoxy- yellow with reddish tint aniline 0.20 moles, 30.64 g of 2,5-dimethoxy- yellow with reddish tint aniline 0.20 moles, 30.24 g of methyl yellow with greenish tint anthranilate 0.20 moles, 41.84 g of dimethyl ester yellow with greenish tint.

of 2-aminoterephthalic acid Example 4 Process for the Preparation of a Pigment in Accordance with the Present Invention by Condensation in a Solvent: 2A-dichloroaniline (32.4 g) is stirred for 3 hours in 89.83 g of 30.59G hydrochloric acid, diluted with ice water and diazotized by the addition of 14.1 g of sodium nitrite, dissolved in water.

Ethyl acetoacetate (26.67 g) is dissolved in 181.54 g of 80% acetic acid and mixed with a solution of 27.2 g of sodium hydroxide in water, the temperature increasing to 300C. The diazo solution is rapidly added dropwise to the solution of the coupling component. After continuing to stir for a further 2 hours, the pigment suspension is filtered off with suction, washed until neutral and dried.

The pale yellow ester pigment obtained (6.67 g) is suspended together with 1.92 g of 6,8 diamino-2,4-dioxotetrahydroquinazoline in nitrobenzene and heated under reflux. The ethyl alcohol, formed by the condensation, is distilled off. After 3 hours, the reaction product is filtered off, washed with benzene and petroleum ether and dried.

Claims

1. A diazo pigment dye having the formula

wherein D is the residue of an aromatic diazo component without a water-solubilizing group.

2. The dye of claim 1 wherein the diazo component is an aromatic amine selected from the group consisting of anilines substituted with chloro, nitro, alkyl, alkoxv or carbonamido.

3. The dye of claim 1 wherein the diazo component is selected from the group consisting of: 2,5-dichloroaniline, 2,4,5-trichloroaniline, 2-amino4-chlorotoluene, 2-amino-5-chlorotoluene, 2-amino-6-chlorotoluene, 2-amino-4-nitrotoluene, 2-amino-5-nitrotoluene, 3-nitro-4-aminotoluene, 2-methoxy-4-nitroaniline, 3-amino-4-methoxy benzanalide, 4-chloro-2-aminoanisole, 2-chloro-4-aminoanisole, 2,4-dimethoxyaniline, 2,5-dimethoxyaniline, methyl anthranilate, and dimethylester of 2-aminoterephthalic acid.

4. A method for preparing the dye of claim 1 comprising coupling a diazotized amine containing residue D with 6,8-diacetoacetyla m ino-2,4-dioxotetrahydroquinazoline.

5. A method for preparing the dye of claim 1 comprising coupling an acetoacetate with a diazotized amine containing residue D, and condensing this product with 6,8-diamino-2,4dioxotetrahydroquinazoline in a solvent.

6. In a method for coloring materials selected from the group consisting of plastics, paints and printing inks, wherein the material is contacted with a diazo pigment, the improvement which comprises said diazo pigment being the pigment of claim 1.