DE3125495A1 - Use of dyes for shading optical brightenings - Google Patents

Abstract

Azo dyes of the formula <IMAGE> where R1 is nitro, cyano, -COOR4, -CONR5R6, -SO2R4 or -SO2NR 5R6, R2 is nitro, cyano, -COOR4, -CONR5R6, -SO2R4, -SO2NR5R6 or an unsubstituted or substituted arylazo group, R3 is hydrogen or alkyl, A and B are each hydrogen, halogen or alkyl, R4 is aryl, aralkyl, cycloalkyl or an aliphatic radical, and R5 and R6 are hydrogen, aryl, aralkyl, cycloalkyl or an aliphatic radical or together with the nitrogen atom a heterocyclic ring, can be used for shading optical brightenings, in particular on polyester, cellulose, cellulose acetate or cotton.

Description

Use of dyes to shade optical brightening.

The present invention relates to the use of dyes for the nuance of optical brightening.

In bleaching and optical brightening, it is a method that is often used Use violet or blue dyes to improve the bleaching or lightening effect. If such a dye is applied together with an optical brightener, this can serve various purposes: a) it can increase the degree of whiteness The aim is to compensate for the yellow content of the fiber, with the result of the brightener Earbton produced on the fiber is largely retained; b) it can with said Dye a change in the shade of that produced by the brightener on the fiber The aim is to achieve a color tone, and an attempt is also made here to add another To achieve an increase in whiteness and c) it can be done with a very small amount of dye a much larger amount of brightener can be replaced, in addition to a desired one To get whiteness. You can use it to create the desired shade of white to adjust.

Particularly interesting white effects are so on fiber materials to achieve with a high basic white, in which the achievement of a low increase In terms of brightness (degree of whiteness) a considerable additional effort in the bleaching or lightening process means. In terms of process technology, the nuance during lightening prepares in continuous Process (e.g. in pad-thermometer experience3 in general no difficulties.

On the other hand, when shading, optical brightening results hydrophobic fibers in the exhaust process with the choice of suitable disperse dyes Significant difficulties: Used to increase the whiteness when lightening of textiles (e.g. polyester) Mixtures of optical brighteners with azo dyes, as proposed, for example, in US Pat. No. 3,762,859 or DE-OS 2,236,300 As a rule, no levelness problems are to be expected, but these dyes are insufficient compared to the chemical bleaching agents often used at the same time stable. In order to be able to nuance even in the presence of bleach, various have been made Mixtures of optical brighteners with bleach-resistant vat dyes recommended; however, these have the disadvantage that they do not result in a level nuance.

The present invention is based on the object selected To find shading dyes which do not have the disadvantages mentioned.

It has now surprisingly been found that azo dyes of the formula wherein R1 is nitro, cyano, -COOR4, -CONR5R6, -S02R4 Qder-SO NR, R 1, R2 is nitro, cyano, -COOR4, -CONR5R6, -SOzR4, -SO NR -R or an unsubstituted or substituted arylazo group, R3 is hydrogen or alkyl, A and B hydrogen or unsubstituted or substituted alkyl, C and B hydrogen, halogen or alkyl, R4 aryl, aralkyl, cycloalkyl or an aliphatic radical and R5 and R6 hydrogen, aryl, aralkyl, cycloalkyl or an aliphatic radical or R5 and R6 together with the nitrogen atom denote a heterocyclic ring, are particularly suitable for shading optical brightening.

Arylazo groups R2 include, for example, aromatic-carbocyclic radicals, in particular those of the benzene series, which may be substituted kör jan, e.g. by halogen, -CN, nitro, carbalkoxy, Trifluoromethyl, alkyl, Alkoxy, -SCN, alkylsulfonyl, arylsulfonyl, aralkylsulfonyl, carbamoyl or sulfamoyl.

Alkyl radicals R3 have 1 to 6, preferably 1 to 4, carbon atoms.

Alkyl radicals A and B have 1 to 6, preferably 1 to 4, carbon atoms and can by chlorine, bromine, cyano, phenyl, hydroxy, alkoxy, acyloxy, alkoxycarbonyl, Phenoxycarbonyl, Alkyiaminocarbonyl or Alkqxycarbonyloxy be substituted. as Acyloxy radicals whose acyl parts are both aliphatic and radical aromatic residues of the benzene series are; Alkoxycarbonyl and alkoxycarbonyloxy groups a total of 2 to 7, preferably 2 to 5, carbon atoms.

Halogen atoms C and D are chlorine or bromine, preferably chlorine, atoms.

Alkyl radicals C and D have from 1 to 6, preferably 1 to 4, carbon atoms.

Aryl, aralkyl and cycloalkyl radicals R4 are e.g. phenyl, benzyl, phenethyl, Phenylpropyl, cyclohexyl and cyclohexyl substituted by alkyl having 1 to 4 carbon atoms.

Suitable aliphatic radicals R4 are alkyl radicals with 1 to 6, preferably 1 to 4 carbon atoms.

Heterocyclic rings that can be formed by R5 and R6 are e.g. the morpholino, piperidino or pyrrolidino radical.

In the context of the azo dyes of the formula (1), those of the formula are of interest wherein A, B, C and D have the meanings given above.

Azo dyes of the formula are important wherein A 'and B' are cyanoalkyl with 1 to 4 carbon atoms in the alkyl part, acyloxyalkyl with a total of 2 to 6 carbon atoms, alkoxycarbonylalkyl with a total of 2 to 6 carbon atoms or alkoxycarbonyloxyalkyl with a total of 2 to 6 carbon atoms and C and D have the meaning given above.

Advantageous azo dyes correspond to the formula as well as the formula in which formulas C and -D have the meaning given above and C 'stands for hydrogen, chlorine or methyl.

The azo dyes of the formula are of practical importance wherein C 'has the meaning given above, and especially the azo dye of the formula The azo dyes which can be used according to the invention for shading optical lightening are sufficiently to completely resistant to bleaching agents such as sodium chlorite and peroxide compounds under the coloring conditions used for lightening and have good leveling properties. They are in combination with the optical. Brighteners can be used for all application methods in question.

The azo dyes of the formula (which can be used according to the invention are mainly for shading lightening on polyester fibers and polyester fiber mixtures used.

Dyes are considered to be sufficiently to completely resistant to bleaching if their depth of color when using 0.01% dye based on the fiber weight regardless of a possible color change in the chlorite bleach bath or peroxide bleach bath does not decrease to more than 50% according to the procedures described. As a measure for the change in color depth applies, for example, a simple color distance formula such as LE = (Ex² + Sy² + bY²) 1/2 between dye F and blind dye B without added dye.

The following mean: E = color difference Ex = xF = = YF - YB #Y = YF -YB where x and y mean the color value proportions and Y the lightness reference value, which is stated on the CIE - 20, D 65 based on color system.

However, other common color difference formulas are also equivalent, which are recommended by the CIE and on one of the CiE recognized Color system based, for example, on the asz b *, L * color system.

The color codes are measured using a standard color measuring instrument.

The calculation of the change in color depth (T) in% is based on the relationship: # E2 # 100 T% = # E1 1 = color difference between coloring and blind coloring, both without Addition of bleach-active substance.

= = Color difference between coloration and blind coloration, both with addition active bleaching substance.

The choice of the dye concentration of 0.01% color-active substance is many times higher than that preferred in combination with optical brighteners dye concentration used.

This is necessary in order to measure the bleaching resistance of the dyeings and to be able to assess visually reproducible.

As colorations with dyestuff, analogously. understood such which with 0.01% F. dye content based on the color-active substance according to the Exhaust process under HT conditions - e.g.

Polyester fabric (Terylene 540) according to the following general rule are applied: liquor ratio 1:20 0.01% dye 1 g / l of the adduct of 35 Mcl of ethylene oxide in 1 mole of stearyl alcohol 2 g / l sodium chlorite 50% and 1 ml / l formic acid 85%.

from 40 to 120 "C / in 30 minutes at 1200 C / 30 minutes from 120 to 40 ° C / 10 minutes, followed by a rinse.

The amount of brightener (pure substance) in the dispersion can, depending depending on the brightener used, between 0.002 and 0.5 X, based on the brightener to be brightened Material, fluctuate.

The amount of shading dye (pure dye) is, depending on Dye and the desired shade, about 0.0025 to 2.5%, preferably 0.025 up to 1.25%, based on the amount of brightener used (pure substance).

The usual polyester brighteners are preferably used as brighteners as well as mixtures thereof are used, which in practice are used together with shading dyes be applied.

These are mostly benzoxazole, coumarin, stilbene, styryl, naphthalimide and pyrene triazine brighteners.

Benzoxazole brighteners include, for example, bis-benzoxazole, styryl or stilbenyl benzoxazole types, especially compounds of the formulas: where the rings A, B, C and D can also contain simple radicals such as lower alkyl or alkoxy groups or chlorine atoms, especially the 2,5-bis-benzoxazol-2-yl-thiophene, the 2,5-bis ( 5-methylbenzoxazol-2-yl) -ethylene and 1,4-bis-benzoxazol-2-yl-naphthalene, or the formula where n = 0 or 1 and the rings A and B can be further substituted, for example with alkyl, alkoxy, phenyl, chlorine, cyano, carboxy and its derivatives, or the ring A is additionally substituted with carbalkoxyalkenyl, pyridazyl, pyrimidyl, oxdiazolyl, cyanoalkenyl can be, for example the compounds: 4-phenyl-4 '- (5-t-butylbenzoxalol-2-yl) stilbene, 4-phenyl-4' - (5,8-dimethylbenzoxazol-2-yl) stilbene, 5,6 -Dimethyl-2- (4-methoxycarbonyl-styryl) benzoxazole, 5,6-dimethyl-2- (4-cyanostyryl) -benzoxazole and 2- (4 1-methoxycarbonyl-stilben-4-yl) -5-methyl-benzoxazole .

The main coumarin brighteners are those of the formula to be mentioned in which Ar is an aryl radical, in particular phenyl or pyrazole radical, R1 and R2 independently of one another are hydrogen, lower alkyl or phenyl optionally substituted with chlorine, alkyl or alkoxy and X is nitrogen or CII, in particular the compounds 3-phenyl-7- ( 3-methylpyrazol-l-yl) coumarin, 3-phenyl-7- (3-methyl-4-phenylv-triazol-2-yl) coumarin, 3- (4-chloropyrazol-1-y1) -7- (3- methyl-4-phenyl-v-triazo 1-2-yl) coumarin and 3-phenyl-7- (naphtho [1,2-d] v-triazol-2-yl) -coumarin.

Of the stilbene brighteners are mentioned: those of the formulas where n is the number 0 or 1 and the rings A, B and C have various substituents such as alkyl, alkoxy, chlorine, cyano, carboxy and their derivatives, and when n is the number 0, the rings C are independently benzoxazolyl, v -Triazolyl, oxdiazolyl, cyanoalkenyl or carbalkoxyalkenyl radicals, in particular the compounds 2-cyano-4- (naphto [1,2-d] v-triazol-2-yl) -4'-chlorostilbene, 4- (naphto [1,2-d] v-triazol-2-yl) -4-methoxycarbonylstilbene, 1,4-bis- (2-cyanostyryl) benzene, 1- (2'-cyanostyryl) -4- (4 "-cyanostyryl) benzene and 4,4'-di- (a-ethoxycarbonylvinyl) stilbene, as well as those of the formula wherein R1 is cyano or C2-C6-alkoxycarbonyl, R2 is hydrogen or C1-C6-alkyl and Q is a radical of the formula where R is hydrogen, methyl, chlorine or C1-C4-alkoxy, R4 is hydrogen, chlorine, C1-C4-alkyl, phenyl, Cl-C4-alkoxy or phenoxy, R5 is unsubstituted or non-chromophore-substituted C1-C4-alkyl, R6 denotes hydrogen, unsubstituted C1-C4-alkyl or unsubstituted C1-C4-alkoxy and R7 denotes hydrogen, unsubstituted C1-C4-alkoxy or unsubstituted C1-C4-alkoxy, as well as those of the formula where R1 and R2 are identical or different radicals from the group consisting of hydrogen and non-chromophoric radicals from the series fluorine or chlorine atoms, phenyl, lower alkyl, lower alkoxy, lower dialkylamino, lower trialkylammonium, acylamino or optionally functionally modified carboxy or sulfo groups, where two adjacent radicals R1 and R2 together can also stand for a lower alkylene group, a fused benzene ring or a 1,3-dioxypropylene group and R3 stands for straight-chain or branched alkyl groups with 1-18 carbon atoms, preferably with 1-6 carbon atoms , which can be substituted by halogen atoms, lower alkoxy, lower alkyl mercapto, aryloxy, aryl mercapto or aryl radicals, or for a group of the formula - (CH2CH20-) R with R = lower alkyl and n = 2 or 3, 22 n or for a group of the formula - (CH2) -CH = CH-R, m = 0 to 5, or for a radical of the formula where R4 and R5 are identical or different radicals from the group consisting of hydrogen and non-chromophoric radicals from the series fluorine or chlorine atoms, phenyl, lower alkyl, lower alkoxy, (Cl-C4) acylamino groups or optionally modified carboxy or sulfo groups, where two adjacent radicals R4 and R5 together can also stand for a lower alkylene group, a fused benzene ring or a 1,3-dioxapropylene group, especially the compound in which R1 and R2 are hydrogen and R3 is methyl.

Among the naphthalimide brighteners are those of the formula where R1 and. R2 denotes hydrogen or alkoxy, to be mentioned, in particular those in which R1 denotes hydrogen and R2 denotes methoxy or in which R1 and R2 each denote ethoxy.

Of the pyrene-triazine brighteners, consider that of the formula mentioned.

The dyes to be used according to the invention are known (cf. DE-OS 22 01 1.12, 23 04 202, 23 04 203, 23 24 512, 23 33 447, 24 38 496 and. 26th 12 792).

The liquor used contains in addition to those according to the invention usable dyes and the optical brighteners advantageously additionally one or more dispersants and optionally also bleaching, wetting, stabilizing and / or other customary dyeing auxiliaries.

Suitable dispersants include: alkali metal salts, especially sodium salts, of alkyl or alkylarylsulfonic acids and carboxylic acids, alkali metal salts, especially sodium salts, of condensation products of arylsulfonic acids with formaldehyde, macromolecular substances that are suitable for liquefying and dispersing, carboxylates of the type of polymerized maleic acid or polymerized acrylic acid and copolymers from maleic acid with allyl acetate. Examples of such dispersants are: Lauryl sulfate Na salt, oleyl sulfate Na salt, oleyl sulfate diethanolamine salt, Benzylnaphthalinsulfosaures Na, di- (2-suffo-1-naphthyl) methane di-Na salt, m-xylenesulfonic acid Na, dodecylbenzenesulfonic acid Na salt, Diethanolamine dodecylbenzenesulphonic acid, Na diisopropylnaphthalenesulphonic acid, di-n-butylnaphthalenesulphonic acid Na, n-propyl-n-hexylnaphthalenesulfonic acid Na, N-oleylmethyltaurine Na salt, Na salt of the condensation product of naphthalene sulfonic acid and formaldehyde, sulfanilic acid sodium salt, Benzenesulfonic acid Na salt, cumene sulfonic acid Na salt, toluenesulfonic acid Na salt, oxethylated Resin bodies, N-polyvinylpyrrolidone, sulphite cellulose waste liquor (CaO-free), starch ether and polysaccharides. However, particularly preferred dispersants are non-ionic, water-soluble ethoxylated or propoxylated fatty alcohols and alkylphenols as well Fatty alcohol polyglycol ethers, e.g. alkanols, alkenols (C8-C22) in various amounts to ethyleneoxy or propyleneoxy groups, Alkyl or aryl polyglycol ethers with up to 50 ethyleneoxy or propyleneoxy groups, such as octyl, nonyl or dodecylpheno lpo lyglyko ether.

The individual components can be separated in the treatment bath be introduced, which is then adjusted to the desired pH will.

However, a concentrated, storage-stable stock dispersion is preferred the optical brightener (s) and the shading dye (s). Such Dispersions contain brightener and dye in the desired ratio. you will be by adding brightener and dye, preferably together with a dispersant, made in a small amount of water. It is advantageous to use this dispersion subjected to a grinding (e.g. in a ball mill) to achieve particle sizes of smaller than 10 µm, preferably smaller than 2 nm.

A part of this stock dispersion (calculated on the basis of the desired amount of brightener in the bath) are introduced into the treatment bath, the optionally also contains a dispersant and / or other auxiliaries. To Adjustment of the desired pH value can be made of polyester fibers in the form of yarn, fabric etc., in the appropriate dyeing equipment with the one thus obtained Dispersion treated.

Since bleach-resistant shading dyes are used, im Whitening bath can be bleached directly. This is preferably added to the liquor Sodium chlorite, acidifies the bath and then heats it to about boiling temperature.

In the present application, “polyester fibers” are understood to be a matter of course also polyester fibers in blended fabrics, e.g. in blended fabrics Po.lyester / cotton too to understand. The nuanced brightening of such blended fabrics the method according to the invention can also be used advantageously with the lightening of the cotton content, with bleaching (e.g. with peroxide) andZ or the various usual finishing and finishing processes (e.g. anti-crease, wash and wear, soft handle and others Equipment) can be combined.

The brighteners of the formula (15) are new and can be prepared in a manner known per se, for example by adding a compound of the formula in an organic solvent and in the presence of basic condensing agents with a compound of the formula condensed, in which Q, R1 and R2 have the meaning given under formula (15) and one of Z1 and Z2 is the OHC group and the other is a group of the formula denote in which D1 denotes an unsubstituted or substituted alkyl, aryl, cycloalkyl or aralkyl radical.

The following examples illustrate the invention without it however, to limit it.

Example 1: 100 g of a 20% whitening agent dispersion of the formula: are with 30 mg of the violet disperse dye of the formula: offset.

The shading dye is advantageously used for this purpose in 5 g of the Brightener dispersion pre-dissolved and heated gently to 60 "C while stirring further diluted with a further 5 g of brightener dispersion.

This mixture is done with the remaining 90 g whitener dispersion Stir homogeneously mixed.

40 g polyester pile fabric Terylene 540 (washed and 20 seconds heat-set at 1800C) are evenly formed as a fabric tape of approx. 250 x 12 cm wound on bobbin tubes and in an HT dyeing machine in a liquor ratio of 1: 9 treated with a liquor containing 0.8% whitening agent dispersion of formula 1 300 ppm of the shading dye of the formula 2 1 g / l of the adduct of 35 ethylene oxide contains 1 mole of stearyl alcohol.

The application takes place at a pH value of 6.5-7.5 according to the following Temperature program: 50 - 1300C in 20 minutes at 1300C for 30 minutes.

The liquor is then drained off and at 250 ° C. for 5 minutes rinsed in running deionized water.

The fabric is then dried at 70 ° C. for 20 minutes.

The fabric treated in this way shows a high degree of flawless quality Equality on.

Example 2: A polyester fabric (Terylene 540) is made on an HT dyeing machine at a liquor ratio of 1:25 with an aqueous bath of the following composition treated: 0.8% brightener dispersion of the formula 1, containing 300 ppm of the shading dye of formula 2 1 g / l of the adduct of 35 moles of alkylene oxide with 1 mole of stearyl alcohol.

The application takes place at a pH value of 6.5-7.5 according to the following Temperature program: 40 - 1200C in 30 minutes 1200C 30 minutes 120 - 40 ° C in 10 minutes.

The textile material is then placed in flowing, deionized water for 20 seconds Rinsed with water and dried at 700C.

The fabric treated in this way has a high degree of whiteness with flawless Equality on.

Example 3: Proceed as described in Example 2, but set 2 g / l sodium chlorite and 1 mUl formic acid (85%) are added to the bath.

The application takes place at a pH value of 3-4 according to the following Temperature program: 40 - 1200C in 30 minutes 1200C 30 minutes 120 - 40 ° C in 10 minutes.

The textile material is then placed in flowing, deionized water for 20 seconds Rinsed with water and dried at 700C.

The fabric treated in this way has a high degree of whiteness with flawless Equality on.

The procedure is as described in Examples 1 to 3, but a dye of the formula is used in which A, B and C have the meanings given in the table, fabrics with a likewise high degree of whiteness and perfect levelness are obtained: Table Connection ABC No. (301) -CH2CH2CN -CH2CH2CN C1 (302) -CH2CH2CN -CH2CH2CN CH3 (303) -CH2CH2CN -CH2CH2OCOCH3 R (304) -CH2Cll2CN -CH2CH2COOCH3 H. (305) -CH2CH2CN -CH2CH20COOC2H5 H. (306) -CH2CH20COCH3 -CH2CH20C0CH3 H. Example 4: Preparation of compounds of the formula (15) 27.5 g of 2- (4-diethoxy-phosphorylmethylphenyl) -4,6-dimethoxypyrimidine and 14.3 g of methyl 4-formylcinnamate are dissolved in 150 ml of dimethylformamide and in the course of 30 minutes - Small portions with 4.9 g of sodium methylate added. The reaction mixture is then stirred for 30 minutes at room temperature and then for a further 2 1/2 hours at 40-45 ° C. After cooling to room temperature, it is acidified with formic acid and stirred into 800 ml of water and ice. The precipitated product is filtered off with Washed water and methanol and dried at 80 ° C. in a vacuum. 28 g of the compound of the formula are obtained The product crystallizes from toluene with the addition of bleaching agents in yellow crystals with a melting point of 169-1700C.

If the procedure is analogous, the compounds of the formula listed in Table I are obtained from the corresponding starting materials Table I. Compound R1 R2 R3 m.p. ° C 402 -OC2H5 -0C2H5 -CH = CH-COOCH3 191-192 403 -OC3H7 -OC3H7 -CH-CH-COOCH3 190-192 404 CH3 -CH3 -CH-CH-COOCH3 193-194 405 -OCH3 -0CH3 -CH = CH-COOCH (CH3) 2 126-127 406 -OCH3 -OCH3 -CH = CH-CN 218-219 407 -OC3H7 -OC3H7 -CH = CH-CN 188-189 408 -CH3 -OCH3 -CH = CH-COOCH3 175-176 409 -CH3 -OCH3 -CH = CH-CN 196-197 410 H -CH3 -CH = CH-COOCH3 207-208 411 H -CH3 -CH-CH-CN 246-248 The 4,6-substituted 2- (4-bromomethylphenyl) pyrimidines required as starting materials for the synthesis of the phosphonates are prepared in the following manner.

102.3 g of p-tolylamidine hydrochloride and 99.3 g of diethyl malonate are suspended in 520 ml of anhydrous ethanol. 323.7 g of a 30% strength sodium methylate solution are then allowed to flow in with thorough stirring and cooling. It is then heated to reflux and stirred under reflux for 4 to 5 hours. After the solvent has been distilled off, the residue is taken up in 1000 ml of water, heated to 80 ° C. and the somewhat cloudy solution is filtered through silica. After cooling, it is acidified with 15% hydrochloric acid. The thick mineral paste is filtered off, washed with water and dried at 1000C. 100-110 g of the compound of the formula are obtained The product has a melting point of 3140C (decomposition).

72.6 g of the dihydroxy compound are heated to boiling with 72.6 g of N, N-dimethylaniline and 363 g of phosphorus oxychloride and stirred under reflux for one hour. After the excess phosphorus oxychloride has been distilled off, the remaining product is treated with ice water to remove the still adhering phosphorus oxychloride, then finely ground with ice water, filtered off, washed with ice water and dried in vacuo at 40-500C. The yield of the compound of the formula is 85.9 g. The product has a melting point of 86-870C.

156.1 g of a 30.5% sodium methylate solution are added to 700 ml stirred anhydrous methanol. The solution will now be within 10 minutes registered with slight cooling 95.64 g of the compound (413). After that, on Heated to reflux and kept boiling for 4 hours.

After the solvent has been distilled off, the product which remains is introduced into 1000 ml of water. To remove the sodium chloride formed, it is finely ground with water. Then filtered off, washed with water and air dried. 90.4 g of the compound of the formula are obtained in this way with a melting point of 61-620C. -115.2 g of 4,6-dimethoxy-2- (4-methylphenyl) pyrimidine are heated with 500 ml of carbon tetrachloride to 70 "C. A mixture of 0.5 g of dibenzoyl peroxide is then added to the solution at 70-75" C. , 1 g of azoisobutyronitrile and 90.8 g of N-bromosuccinimide entered with simultaneous irradiation with a 500 watt lamp within 30 minutes.

To complete the reaction, the mixture is refluxed for a further 2/2 hours. The succinimide is then filtered off at 650 ° C. and the filtrate is evaporated to dryness. 144 g of crude product of the formula are obtained The product can be purified by recrystallization from AethanoVAethylene glycol monomethyl ether (1: 1) (melting point 132-1349C).

In an analogous manner are those for the production of the compounds of the formula (402) to (411) required bromomethyl compounds prepared.

Example 5: 5.2 g of the phosphonate of the formula and 3.0 g of methyl 4-formylcinnamate are added dropwise in 30 ml of dimethylformamide with the addition of 3.2 ml of a methanolic sodium methylate solution (content: 30.7%), the temperature being kept below 450 ° C. by cooling with ice water. The mixture is then stirred for 2 1/2 hours at 40-45 "C, the resulting suspension is cooled to 100 ° C, 67 ml of methanol, then 94 ml of water are added dropwise, neutralized with 0.5 ml of 50% acetic acid, and after cooling to 5" C, the one that crystallizes out Product filtered off with suction, washed with about 200 ml of methanol / water and dried under vacuum at 70-800C. After two recrystallization from 300 ml of chlorobenzene each time, 3.0 g of the compound of the formula are obtained as a light yellow, greenish crystal powder.

Melting point: 244-2450C.

Analogously as described in the preceding example, one receives the compounds of the formula Table II Connection AB No. (503) - </ 0 \ il (504) --CH-CH-COOCH3 3 (\ H3 / </ \ (505) ~ -CH = CH-COOC2H5 (506) Ii I -CH = CHCO0C2H 1 (507) \. # - -CH = CH-COOCH3 .. (508) ./ </ \ -CH = CH-COOCH 3 H3 Table II continued Connection AB B. No. I. (509) il! v - -CH = CH-CN . ~~~ ... (slo) \ 0 (511) CH3- - -CH = CH-COOC2H5 L5 (512) / to -CH = CH-COOC2H5 CH3 . ~ ~ il I -CB = CH-CN (513) t; \. -CI = CR-CN,

Claims (9)

-Patent claims 1. Use of azo dyes of the formula whereinR1 nitro, cyano, -COOR4, -CONR5R6, -S02R4 or -S02NR, R ,, R2 nitro, cyano, -COOR4, -CONR5R6, -S02R4, -S02NR5-R6 or an unsubstituted or substituted arylazo group, R3 hydrogen or alkyl, A and B are hydrogen or unsubstituted or substituted alkyl, C and D are hydrogen, halogen or alkyl, R4 is aryl, aralkyl, cycloalkyl or an aliphatic radical and R5 and R6 are hydrogen, aryl, aralkyl, cycloalkyl or an aliphatic radical, or R5 and R6 together with denote the nitrogen atom a heterocyclic ring, for shading optical brightening. 2. Use according to claim 1 of azo dyes of the formula wherein A, B, C and D have the meaning given in claim 1. 3. Use according to claim 2 of azo dyes of the formula wherein A 'and B' are cyanoalkyl with 1-4 carbon atoms in the alkyl part, acyloxyalkyl with a total of 2 to 6 carbon atoms, alkoxycarbonylalkyl with a total of 2 to 6 carbon atoms or alkoxycarbonyloxyalkyl with a total of 2 to 6 carbon atoms and C and D is hydrogen, halogen or alkyl. 4. Use according to claim 3 of azo dyes of the formula wherein C and D are hydrogen, halogen or alkyl. 5. Use according to claim 4 of azo dyes of the formula where D is hydrogen, halogen or alkyl and C 'is hydrogen, chlorine or methyl. 6. Use according to claim 5 of azo dyes of the formula wherein C 'is hydrogen, chlorine or methyl. 7. Use according to claim 6 of the azo dye of the formula 8. Mixture consisting of an optical brightener and an azo dye of the formula wherein R1 is nitro, cyano, -COOR4, -CONR5R6, -SO2R4 or -SO2NR5R6, R2 is nitro, cyano, -COOR4, -CONR5R6, -SO2R4, -SO2NR5-R6 or an unsubstituted or substituted arylazo group, R3 is hydrogen or alkyl, A and B. hydrogen or unsubstituted or substituted alkyl, C and D hydrogen, halogen or alkyl, R4 aryl, aralkyl, cycloalkyl. or an aliphatic radical and R5 and R6 are hydrogen, aryl, aralkyl, Cycloalkyl or an aliphatic radical or R5 and R6 together with the nitrogen atom mean a heterocyclic ring 9. The one with a mixture consisting of an optical brightener and an azo dye of the formula wherein R1 is nitro, cyano, -COOR4, -CONR5R6, -SO2R4 or -SO2NR5R6, R2 is nitro, cyano, -COOR4, -CONR5R6, -SO2R4, -SO2NR5-R6 or an unsubstituted or substituted arylazo group, R3 is hydrogen or alkyl, A and B hydrogen or unsubstituted or substituted alkyl, C and D hydrogen, halogen or alkyl, R4 aryl, aralkyl, cycloalkyl or an aliphatic radical and R5 and R6 hydrogen, aryl, aralkyl, cycloalkyl or an aliphatic radical or R5 and R6 together with the nitrogen atom mean a heterocyclic ring, lightened material made of polyester, cellulose, cellulose acetate or space wool.