DE1051784B - Optical brighteners - Google Patents

Description

Optical brightening agents The present invention relates to the use of such bluish fluorescent compounds of the stilbene series as brightening agents which have the general formula correspond, in which R stands for hydrogen, an alkyl, aralkyl or aryl radical and in which X1 and X, independently of one another hydrogen, represent a soluble group - such as e.g. B. a sulfo or carboxyl group, a sulfonamide group, an alkyl or aryl sulfone group, a carbonamide group or a nitrile group, while Y stands for hydrogen or a substituent; Examples of substituents which may be mentioned are halogen, the nitrile group, an acylamine group or a radical which — optionally substituted — contains triazine, triazole or tetrazole rings. Suitable representatives of the proposed new type of brightening agents of the stilbene series are e.g. B. the following connections: The compounds to be used as brighteners can have been produced in a variety of ways. One way to produce them is z. B. in that one of aminostilbene tetrazoles of the general formula in which X1, X2 and R have the meaning given above, and the free amino group of these compounds is then modified by known processes in the manner required in each case for the various brightening agents. Aminostilbene tetrazoles suitable for this purpose can be obtained from stilbene compounds of the general formula obtained, in which X1 and X2 have the meaning given above and in which Z is a radical which can be converted into the primary amino group, e.g. B. an acylamino or a nitro group, by diazotization, coupling to mono- or diacylhydrazines, ring closure in an alkaline medium to the tetrazole derivative and conversion of the radical Z into a primary amino group.

Another way of preparing the lightening agents of the stilbene series to be used according to the invention consists in using amines of the general formula in which X1, X2 and Y have the meaning given above, diazotized, the diazonium compounds on diacylhydrazines or monoacylhydrazines, z. B. diformyl hydrazine, diacetyl hydrazine or benzoyl hydrazine, couples and the coupling products are converted into the tetrazoles in an alkaline medium. According to the invention, the lightening agents can be used for treating a wide variety of materials; for example, textile materials of a natural or synthetic type are mentioned - e.g. B. structures made of wool, natural or regenerated cellulose, cellulose acetate, polyesters, polyamides or polyacrylonitriles - or the unshaped masses used for their production, as well as plastics, resins, lacquers, soaps, leather and paper. The agents are used in the customary manner, generally in the form of solutions in water or organic solvents or in the form of dispersions. The lightening agents of the present invention can also be used together with detergents. If necessary, the quantities required in each case can easily be determined by means of preliminary tests.

The agents of the present invention stand out from the known ones Brightening agents of the stilbene series, the triazole rings instead of tetrazole rings included, with a better whitening effect.

The parts given in the following examples are parts by weight. Percentages are percentages by weight. Example 1 White cotton material is treated for 20 minutes in a liquor ratio of 1:20 in an aqueous bath containing 0.04 g per liter of the lightening agent of the formula contains; the temperature is gradually increased from an initial 23 ° C to 40 ° C. After the usual rinsing and drying, the cotton material is significantly lighter in white. The brightening agent used was prepared in the following manner; 96.9 parts of the sodium salt dex J # minostilbene naphthotriazole trisulfonic acid. the formula were dissolved in 400 parts of water with 10.2 parts of sodium nitrite, poured into a mixture of 40 parts by volume of concentrated hydrochloric acid (d = 1.18) in 300 parts of ice water while cooling with ice and stirred for 20 minutes. After removing the excess nitrous acid with sulfamic acid, the approximately 800 parts by volume of the diazo suspension was poured at -10 ° C with stirring into a solution composed of 12.8 parts of diformylhydrazine and 50 parts of sodium chloride with the addition of 50 parts of about 45% sodium hydroxide solution 200 parts of water was prepared. The mixture obtained in this way was then stirred at about 20 ° C. until a sample with the sodium salt of 1-O.xynaphthalene, 4-sulfonic acid no longer gave a violet dye, and then made alkaline with 100 parts of sodium bicarbonate. The precipitate which separated out was filtered off with suction and purified by repeated dissolving from little boiling water with the addition of dithionite and charcoal.

Example 2 Unbleached cotton material is treated for 1 hour at 20 ° C. in a liquor ratio 1:20 in a bleaching solution containing 2 g of active chlorine and 0.02 g of the lightening agent of the formula per liter contains. After rinsing and drying, the cotton material shows a pure white that appears more radiant than would be the case without the use of the lightening agent.

To prepare the bleaching solution, 500 parts by volume of a chlorine liquor, which contained 4 g of active chlorine per liter. with 300 parts by volume of a buffer solution added, the of 500 parts by volume of 2N soda solution, 100 parts by volume "/,. hydrochloric acid and 400 parts by volume of distilled water was prepared; the mixture was then made with Hydrochloric acid adjusted to p $ 11 and with distilled water to 1000 parts by volume filled up.

The brightening agent used was prepared in the following manner been: A solution of 35 parts of table salt in 7:40 parts of water was 35 parts by volume 45% sodium hydroxide solution and then an ice-salt mixture cooled to - 10 ° C. After 8.8 parts of diformylhydrazine had been dissolved in this mixture were, the orange-yellow diazo paste quickly became at -10 to -15 ° C with stirring entered by dissolving 44.4 parts of the sodium salt of 4-nitro-4'-aminostilbene-2,2'-disulfonic acid in 300 parts of water, adding 7 parts of N sodium nitrite, stirring into a mixture from 27.5 parts. Hydrochloric acid (d --- 1.18) and 50 parts of ice, 1/2 hour. Diazotize was obtained at 0 to 5 ° C and suction of the diazo compound.

Immediately after adding the diazo paste, the resulting 40 parts of sodium bicarbonate were added to the deep brown solution and quickly adjusted to 15 ° C heated. After the coupling had ended, the reaction mixture was stirred for a further 5 minutes. then with ice cooling again with 35 parts by volume about 45% Caustic soda added, stirred for 6 hours at room temperature, with 40 parts of sodium bicarbonate added and then stirred for another 1/2 hour.

The precipitate formed was filtered off with suction while it was still moist in a boiling mixture of 60 parts of iron powder, 20 parts of glacial acetic acid and 200 Parts of water entered and reduced at 95 ° C for 1/2 hour. Then the reaction mixture became made alkaline with soda and filtered hot. The residue was three times with Boiled water. The filtrate thus obtained, amounting to about 800 to 900 parts by volume 15% sodium chloride was added while it was still warm and the mixture was stirred until it had cooled down. By suction and drying, the 4-amino-4'- [1-tetrazo-lyl- (1,2,3,4)] stilbene-2,2'-disulfonic acid became Obtain sodium in the form of yellow crystals.

. 46.7 parts of 4-amino-4 '- [tetrazolyl- (1,2,3,4)] - stilbene-2,2'-disulfonic acid sodium were partially dissolved in a solution of 7 parts of sodium nitrite in 600 parts of water and at 0 ° C stirred in a mixture of 27.5 parts of concentrated hydrochloric acid and 100 parts of ice. It was dianotized for 1/2 hour while cooling with ice, and the diazo suspension was then stirred into the slurry of 15 parts of β-naphthylamine in 13 parts by volume of concentrated hydrochloric acid and 400 parts of ice and water. The mixture was made acetic acid with 20 parts of soda and 22 parts of sodium acetate, stirred until the coupling was complete, then 10% sodium chloride was added while hot and then cooled. The dye formed was then filtered off, dissolved in 600 parts of boiling water and crystallized at 90 to 95 ° C. with a solution of 62 parts. Copper sulfate in 140 parts by volume of concentrated ammonia and 140 parts by volume of water are added. The initially red mixture was stirred at this temperature until a drop of the solution on filter paper gave a light brownish spot instead of a red one. The triazole crystallized out of the warm reaction mixture was filtered off, dissolved in dilute soda solution, decoppered with sodium sulfide and then salted out of the filtered solution with saturated sodium chloride solution. After suctioning off and drying, the lightening agent was then obtained in the form of a light yellow, crystalline powder. Example 3 White or light yellow fibrous material from the polycondensate of a-caprolactam is a liquor ratio of 1: 30 treated with a bath containing 0.01 g per liter of the whitening agent of the formula and has been adjusted to pH 4 with acetic acid. The temperature of the bath is initially around 15 ° C and is slowly increased to 90 to 95 ° C. After the fiber material has been treated at 90 to 95 ° C. for about 10 to 20 minutes, it is rinsed and dried; it then shows a strong, neutral white brightening.

The whitening agent was made in the following way: 46.7 Parts of 4-amino-4'- [1-tetrazolyl- (1,2,3,4)] -stilbene-2,2'-disulfonic acid sodium were, as described in the example, dianotized, and the diazo suspension was in a solution of 25 parts mixed with 14 parts of soda and 14 parts of sodium acetate Sodium 2-aminonaphthalene-5-sulfonic acid is stirred into 300 parts of water and ice-cooling. After the coupling had ended, the reaction mixture was heated to 90 to 95 ° C, mixed with 20% common salt and stirred until cooled. The dye formed was filtered off with suction, dissolved in 1000 parts of hot water with an alkaline soda solution at 90 to 95 ° C with a solution of 62 parts of crystallized copper sulfate in 140 parts by volume concentrated ammonia and 140 parts by volume of water and stirred until one Drop the solution onto filter paper instead of a red a light brownish spot erab. Then the ammonia was boiled off and the solution was filtered hot; the The filtrate was treated with sodium sulfide and charcoal on the heat, again hot filtered, and the now copper-free filtrate was finally treated with a little sodium dithionite clarified. After the addition of 120 parts of common salt at 80 to 90 ° C, the precipitated Product suctioned off while hot. By repeatedly dissolving in hot water, adding Table salt and vacuuming in the heat was used in the above-mentioned whitening agent Obtained in the form of a crystalline, greenish yellow powder.

Claims (1)

PATENT CLAIM: Use of such bluish fluorescent compounds of the stilbene series, those of the general formula correspond, in which R stands for hydrogen, an alkyl, aralkyl or aryl radical and in which X1 and X2 are independently hydrogen, a solubilizing group, a sulfonamide group, an alkyl or aryl sulfone group, a carbonamide group or a nitrile group, while Y stands for Is hydrogen or a substituent as an optical brightening agent. Documents considered: German Patent No. 911368.