CH643284A5 - METHOD FOR THE PRODUCTION OF AZO DYES. - Google Patents

Description

The invention relates to a process for the preparation of low-copper azo dyes which have at least one cyano group in the diazo component ortho-constant to the azo bridge, by reacting corresponding ortho-halogen azo dyes with metal cyanides in the presence of copper-I compounds.

The process is characterized in that a mixture of 25-95 mol% CuCN, preferably 30-80 mol%, based on the halogen to be exchanged, and at least 5-75 mol% Zn (CN) 2, preferably 20-70 mol%, used, the copper-I-cyanide being used as such or bound in a complex form or being prepared in the reaction medium from copper-I or copper-II compounds.

The use of prefabricated CuCN is preferred, a slight excess of Zn (CN) 2 sometimes being advantageous.

The process is particularly suitable for the preparation of azo dyes of the formula I.

n 1 or 2

Ri is hydrogen, halogen, alkyl, cyan, OV or -COOW R2 is hydrogen, alkyl, aralkyl, aryl or cycloalkyl Rj is hydrogen, alkyl, alkenyl or aralkyl s R4 is alkyl V alkyl, alkenyl, aralkyl or aryl W is hydrogen or V,

wherein the above alkyl, aralkyl, alkenyl, cycloalkyl and aryl lo radicals mentioned in any context are optionally substituted by nonionic substituents or -COOH customary in the chemistry of azo dyes.

Bulky residues are in positions where they do not cause steric hindrance, e.g. tert-butyl in the m-15 or p-position of a phenyl radical.

Cycloalkyl is preferably understood to mean cyclohexyl which is optionally substituted once by C1-C4-alkyl, OH, CN, halogen or Ci-C4-alkoxy.

Suitable aryl is in particular 1-3 times phenyl substituted by halogen, 20 Ci-Gt-alkyl, Ci-C »-alkoxy, nitro, cyclohexyl or phenyl, the last three radicals preferably occurring only once.

Halogen is fluorine, chlorine, bromine or iodine, preferably bromine and chlorine.

25 Suitable alkenyl residues have 2-6 C atoms.

Suitable alkyl and alkoxy radicals have 1-6 C atoms, the alkyl radicals in particular having a further substituent, such as halogen, cyano, alkoxy, aryl, aryloxy, acyl or acyloxy or such as those of the type given in the following form 30, can wear.

Dyes of the formula III can preferably be prepared using this novel process

35 z

40

-n = n-

n rl 4

(iii)

,1

(cn)

/ r a-n = n - <(n-n and IV

r

\

r.

50

^ owo> - <?

(iv)

from corresponding halogen azo dyes of the formula II .1

-n rj

(ii)

represent. Here mean

55 Y hydrogen or a group -NO2, -CN, -V, -OV, -CF3, -SO2V, -SO2CF3,

/ Ri / R5

-SOîN ^, -F, -CI, -Br, -COV, -COOW, -CON <^

60 \ r6 R6

wherein

A an aromatic-carbocyclic radical, preferably from the benzene or naphthalene series, a (benz) isothiazole radical or also a pyrazole radical,

X is a halogen substituent, preferably chlorine or bromine, which is located in the radical A in the o-position to the azo group,

or -N = N-R7

where R5 and R6 are hydrogen or identical or different substituents, which together can also be part of a 65 heterocyclic ring, R7 is aryl or hetaryl,

Z is hydrogen or substituents, among them the preferred

643284

Groups -NO2, -CN, -V, -OV, -CFs, ^ R5

-SO2V, -SO2NC

-CI, -Br, -COV and heterocycles of the formulas V, VI and VII

w ~ / R8

H ß \ -

\ o> "w / x s ^ -

r r

(v)

(vi)

(vii)

where Rs is methyl or together with R9 is a fused-on benzene ring and R9 is -CO2CH3 or -CO2C2H5,

Zi is hydrogen or substituents, among these the groups -NO2, -CN, -V, -OV, CF3, -SO2V,

-so2n <

-Rs

-Ra

-CI, -Br, -COV and in which Z and Zi can also together form a fused isothiazole ring, R '1 is hydrogen, halogen, alkyl, alkoxy,

R'2 is hydrogen, optionally by a cyan, chlorine, bromine, -COCH = CH2, phenyl, -S02CH = CH2, -C02-alkyl, -OCO-alkyl, -0C02alkyl, -0C02-phenyl, alkoxy, Phe-noxy -OCONH-alkyl, -OCONH-phenyl, -OPO (OQ>, PO (OQ) 2 substituted alkyl, - (C2H40) mH, - (C2H40) mC0Q where m 1,2,3,4,5 and Q alkyl, Mean alkenyl or phenyl,

R'j is hydrogen, cyclohexyl, phenyl or R'2

R'4 C1-C4-alkyl, optionally substituted by cyano,

Chlorine, bromine, carbamoyl, carboxyl or carbalkoxy.

Dyes of the formula VIII can be particularly preferably by this new process

1

° 2 "MO> -n => I

-V

3rd

produce. Here mean

R'2 is hydrogen, optionally by phenyl, -CN, -CO2-alkyl, -OCO-alkyl, (Ci-C4) -0C02-alkyl (C1-C4) -0C02-phenyl, alkoxy (C1-C4), phenoxy, -CONH-alkyl (C1-C4 and -OCONH-phenyl substituted C1-C5-alkyl, R'3 cyclohexyl, phenyl or R'2 R'4 Ci-Gt-alkyl, optionally substituted by cyan, carbamoyl, carboxyl or carbalkoxy.

All solvents previously described for halogen-cyano exchange are suitable as solvents. Here come polar protic solvents such as monoalkyl ethers of ethylene or diethylene glycol and especially polar aprotic solvents such as e.g. which if applicable on

Nitrogen alkylated carboxamides and lactams, dialkyl sulfoxides, trialkyl phosphates, hexa-alkylphosphoric triamides and carboxylic acid nitriles.

Examples include:

5

Glycol monomethyl ether, glycol monoethyl ether, diethy-lenglykolmono-methyl ether, diethylene glycol monoethyl ether, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, tetramethylurea, dimethylsul-10 foxide, tetramethylene sulfonate, tetramethylene sulfonate -thylphosphoric triamide, acetonitrile. Water is also an option. The reaction temperature is generally between 20 to 220 ° C, with temperatures between 20 and 150 ° C being preferred.

After the reaction has ended, the reaction products can - if necessary - be precipitated by polar solvents. For this purpose, particularly volatile organic solvents such as acetone and chloroform are suitable, but especially water and especially polar, protic solvents such as lower alcohols with 1-4 carbon atoms.

A particularly preferred variant of the process according to the invention is characterized in that a mixture of 25-95 mol%, preferably 30-80 mol% of a cyanide-free copper (I) compound and the equivalent amount (ie 100 mol%) zinc cyanide (or a slight excess thereof) is used. The mol% relate to halogen to be exchanged. Suitable copper (I) -30 compounds are e.g. CuBr, CuCl, CuJ, CU2O.

The new process makes it possible to produce low-copper dyes in a reproducible manner.

Otherwise, the solvent or solvent mixture, such as e.g. Dimethylformamide / methanol, which is obtained in the 3s filtrate of the cyanoazo dye, can easily be recovered or separated by distillation.

example 1

40 45 g of zinc cyanide are added to a suspension of 322 g of 3-methyl-4- (2 ', 6'-dibromo-4'-nitrophenyl-azo) -N-butyl-N-acetoxyethylaniline in 600 ml of N-methyl-pyrrolidone and 40 g copper (I) cyanide. The mixture is heated to 80 ° C., held at this temperature for 30 minutes, then the temperature is increased to 105 ° C. and 45 hours are kept at 105 ° C. for an hour. After cooling to room temperature, 700 ml of methanol and 88 g of substituted iron (III) chloride are introduced. The mixture is stirred for 6 hours, 350 ml of water are added and the mixture is stirred for a further 12 hours. The dye is then filtered off, washed with 300 ml of methanol, 800 ml of 10% hydrochloric acid and 21 water. After drying, 220 g of the corresponding dicyan dye with a copper content of <0.3% are obtained.

If CuCN is used exclusively and analogous copper removal results in a significantly higher copper content.

Example 2

With the same approach, 54.4 g of copper (I) cyanide and 35.6 g of zinc-60 cyanide are used instead of the abovementioned amounts of cyanide. Working up analogously gives 225 g of dicyc dye with a copper content of <0.3%.

With an analog or similar procedure, the dyes listed in the table below can be obtained in good yield.

643284

% Cu (l) compound% Zn (CN) 2

related to exchange. Halogen cn

Br- <PS-N ~ N-.

cn ch

-n.

/ c2h5

nc2h4ok

50

50

o2n n

-n = n-a)> - n n / w ch2ch2cn

/ c2h5

c2h5

40

60

cn

-n

/ C2H5 ■ ° 2H5

60

ch2ch2002ch3

40

80

20th

œ2œ2co2ch3

01 Œ3

30th

70

YY

Claims (3)

643 284 1. A process for the preparation of azo dyes which have at least one cyano group in the diazo component ortho to the azo bridge, by reacting corresponding ortho-halo azo dyes with metal cyanides in the presence of a copper (I) compound, characterized in that the reaction is carried out with a Mixture of 25-95 mol .-% CuCN, based on halogen to be exchanged and at least 5-75 mol .-% Zn (CN) 2, wherein the copper-I-cyanide is used as such or in complex form or in the reaction medium made of copper -I- or copper-II connections is made. 2. The method according to claim 1, characterized in that one carries out the reaction in polar aprotic solvents. 2nd PATENT CLAIMS 3. The method according to claim 1, characterized in that one carries out the reaction at temperatures between 20 and 150 ° C.