RU2068429C1 - Process for preparing cyanogroups containing azo dyes - Google Patents

Abstract

FIELD: dyeing of synthetic fibers. SUBSTANCE: process comprises reacting halogen containing azo dyes with cyanating agent in the presence of copper catalyst and base, and optionally promoters, such as alkali metal halides or quaternary ammonium salts. The cyanating agent is acetone cyanohydride. The claimed process makes it possible to obtain product with yield o 93-97%. Cyanation efficiency for the claimed cyanating agent is 0.9-0.98. EFFECT: improved properties of the cyano groups containing azo dyes.

Description

(I)
где Х=Н, Сl, Br, NO₂, CN;
Y=H, NO₂, Cl, Br, алкил, алкоксикарбонил;
А и А¹=H, алкил, алкоксил, галоген, ациламиногруппа;
R алкил, оксиалкил, алкоксиалкил, цианэтоксиалкил, феноксиалкил, ацилоксиалкил, цианалкил, алкоксикарбонилалкил, аралкил, алкенил.The invention relates to the technology of dispersed monoazo dyes containing a cyano group, in particular to a method for producing dispersed dyes of the formula (I)

(I)
where X = H, Cl, Br, NO ₂ , CN;
Y = H, NO ₂ , Cl, Br, alkyl, alkoxycarbonyl;
A and A ¹ = H, alkyl, alkoxyl, halogen, acylamino group;
R alkyl, hydroxyalkyl, alkoxyalkyl, cyanoethoxyalkyl, phenoxyalkyl, acyloxyalkyl, cyanoalkyl, alkoxycarbonylalkyl, aralkyl, alkenyl.

R ¹ = H or has one of the meanings R.

 Dispersed dyes of the formula (I) are important for dyeing synthetic fibers, especially polyester fibers, in colors from red to blue.

A known method of producing dyes of formula (I) by replacing chlorine or bromine atoms with a cyano group in halogen-containing dyes by reacting with copper cyanide in a medium of dimethylformamide type solvents [1]
However, due to the need to work with highly toxic hydrocyanic acid salts, it is practically impossible to organize and operate such plants; in addition, a significant amount of by-products (up to 15-25%) are formed during the reaction, which subsequently remain as impurities in the target dye, reducing its quality or impurities are removed by conventional methods (crystallization, washing with solvents), but the yield is reduced to 50-60%
To create industrial production of cyanide dyes of the formula (I), the most important task is to increase safety by eliminating highly toxic hydrocyanic acid salts from the synthesis.

 Among the known cyanide-free methods of obtaining the best result is the use of formamide as a cyanidating agent.

где X, Y= H, галоген, алкил, алкоксил, CN, NO₂, SO₂NR², SO₂R, CONR², COOR¹;
W=хлор, бром, йод;
Z=H, алкил, алкоксил, ациламиногруппа;
V=H, алкил, алкоксигруппа;
U=H, галоген, алкил, алкоксил, NO₂, SO₂R;
R¹ углеводородный остаток;
R² H или имеет значение R¹
с формамидом в присутствии медного катализатора, уксусного ангидрида и связывающего кислоту агента (основания) при этом получают азокрасители формулы (III)

где Q CN или имеет значение Y
X, Y, Z, U, V, R¹ и R² имеют указанные выше значения [2]
Недостатком способа является низкий выход красителя и образование большого количества примесей, поскольку формамид является реагентом как в основной (цианирование), так и побочных (восстановительных) реакциях.This method, selected as a prototype, consists in the interaction of a halogen-containing azo dye of the formula (II)

where X, Y = H, halogen, alkyl, alkoxyl, CN, NO ₂ , SO ₂ NR ² , SO ₂ R, CONR ² , COOR ¹ ;
W = chlorine, bromine, iodine;
Z = H, alkyl, alkoxyl, acylamino;
V = H, alkyl, alkoxy;
U = H, halogen, alkyl, alkoxyl, NO ₂ , SO ₂ R;
R ¹ hydrocarbon residue;
R ² H or R ¹
with formamide in the presence of a copper catalyst, acetic anhydride and an acid-binding agent (base), azo dyes of the formula (III) are obtained

where Q CN or Y
X, Y, Z, U, V, R ¹ and R ² have the above meanings [2]
The disadvantage of this method is the low yield of the dye and the formation of a large number of impurities, since formamide is a reagent both in the main (cyanidation) and side (reduction) reactions.

 The objective of the invention is the search for a new cyanide-free cyanide agent that would be low toxic and provide a large yield of target cyanide dyes and improve their purity by suppressing side processes.

 This problem is solved by using acetone cyanohydrin as a cyanating agent in combination with catalysts based on copper compounds, bases and, if necessary, also promoters of pyridine or alkali metal halides or quaternary ammonium salts.

 A significant difference of the proposed method is the use of acetone cyanohydrin as a cyanating agent.

 The latter is an affordable and cheap industrial product, many orders of magnitude less toxic than hydrocyanic salts.

где значения X, Y, A, A¹ R и R¹ приведены выше
получают каталитическим взаимодействием галогенсодержащих моноазокрасителей формулы (IV)

Z=Cl, Br
с ацетонангидрином.In accordance with the proposed method, dispersed monoazo dyes of the formula (I)

where the values of X, Y, A, A ¹ R and R ¹ are given above
obtained by catalytic interaction of halogen-containing monoazo dyes of the formula (IV)

Z = Cl, Br
with acetone anhydrin.

 The reaction conditions are not limited to any narrow scope and the positive effect of the use of a new cyanating agent is achieved in a wide range of variation of parameters.

 As catalysts, it is better to use compounds of monovalent copper, for example, copper monochloride.

 The amount of catalyst from 2-3 mol. to equimolar and even a slight excess.

 As the base used, for example, sodium, potassium or calcium carbonates or hydroxides, sodium or potassium acetates, calcium, magnesium oxides, sodium tetraborate, trisubstituted sodium or potassium phosphates in an amount of at least 1 equivalent per 1 introduced cyano group.

 The reaction temperature is from room temperature to the boiling point of the solvent.

 As a solvent, polar aprotic dimethylformamide, N-methylpyrrolidone or polar protonic ethyl cellosolve, alcohols, water or mixtures thereof are used.

 Reaction conditions: the amount of catalyst, the type of base depend on the structure of the original halogen-containing dye of the formula (IV).

 The reaction temperature also depends on the solvent (in protic solvents the temperature is higher than in aprotic ones) and on the type of exchangeable halogen atom (group Z 'in formula (IV) Cl or Br): the Br atom exchanges under milder conditions.

 To smoothly replace the halogen atom with a cyano group in the compounds of formula (IV) in some cases it is advisable to add promoters that contribute to a more complete suppression of side reactions.

 Many compounds that form complexes with monovalent copper can serve as a promoter, but for practical and economic reasons, pyridine or alkali metal halides or quaternary ammonium salts are most effective.

 The number of promoters can be from catalytic to close to equivalent.

 Specific conditions for the implementation of the proposed method are given in the examples.

 PRI me R 1.

Obtaining 2-cyan-4,6-dinitro-2 ¹ -acetylamino-4 ¹ -dibutylaminoazobenzene (in the conditions of the prototype).

A mixture of 5.35 g (0.01 mol) of 2-bromo-4,6-dinitro-2 ^1- acetylamino-4 ¹ -dibutylaminoazobenzene, 0.2 g (0.001 mol) of copper iodide, 2.5 g (0.03 mol) of anhydrous sodium acetate, 1.8 g (0.04 mol) of formamide, 4.8 g (0.04 mol) of acetic anhydride and 22 ml of butyl acetate are heated for 15 minutes to 110 ^{° C.} and 50 minutes at 110 ^° C. It is cooled to 20 ^{° C.} , the precipitate is separated, washed with a small amount of alcohol, dried, and the desired dye is obtained with a yield of 84% cyanation selectivity (ratio of the yield of the target product to the sum of the outputs of the target and by-products) 0.83.

 The dye (hereinafter after being converted into a dispersed form) dyes the polyester fiber with a high-temperature method in blue.

 Examples 2-15 are carried out in the conditions of the proposed method.

PRI me R 2
Preparation of 2-cyano-4,6-dinitro-2 ¹ -acetylamino-4 ¹ -dibutylaminoazobenzene.

To a solution of 5.35 g of 2-bromo-4,6-dinitro-2 ^1- acetylamino-4 ¹ -dibutylaminoazobenzene (0.01 mol) in 40 ml of dimethylformamide, 0.8 g of sodium carbonate (0.00755 mol) is added at room temperature ) and 1 g of copper monochloride (0.01 mol), then 1.05 ml (0.0115 mol) of acetone cyanohydrin is poured in 1 dose, stirred for 3 hours at 20 ^° C, 2 hours at 40-45 ^° C and 30 minutes at 70 ^o C, monitoring the progress of the reaction by TLC (silofol, benzene). Cool, pour 100 ml of water, 1 ml of a saturated aqueous solution of ferric chloride and 10.5 ml of 5% hydrochloric acid, mix for several hours at 20 ^o C, the precipitate is separated, washed with water, dilute ammonia solution, 80% isopropyl alcohol and again with water, dried and get the target product with a yield of 92.6% selectivity cyanidation (the ratio of the yield of the target product to the total yield of the target and by-products) of 0.94. The dye dyes the polyester fiber in a bright blue color, the dyes are significantly brighter in color than those obtained in a similar way using the dye in example 1.

PRI me R 3
Preparation of 2,6-dicyan-4-nitro-2 ¹ -propionylamino-4 ^1- diethylaminoazobenzene.

To a mixture of 5.27 g of 2,6-dibromo-4-nitro-2 ¹ -propionylamino-4 ^1- diethylaminoazobenzene (0.01 mol), 0.4 g of copper monochloride (0.04 mol), 0.77 g of oxide calcium (0.0138 mol) and 200 ml of ethyl cellosolve at 100-105 ^° C over 3 hours are added dropwise to a solution of 2.1 ml of acetone cyanohydrin (0.023 mol) in 10 ml of ethyl cellosolve, heated for another 3 hours at 100 105 ^o C, cool and pour 500 ml of water; after isolation, analogously to example 2, the target dye is obtained, yield 96.7%, cyanination selectivity 0.91. The dye dyes the polyester fiber with a high-temperature method in a bright blue color with a green tint.

PRI me R 4
Preparation of 2,6-dicyan-4-methyl-2 ^1- methylsulfonylamino-4 ^1- diethylaminoazobenzene.

To the mixture, 0.099 g (0.001 mol) of copper monochloride, 2.6 g of 2,6-dibromo-4-methyl-2 ^1- methylsulfonylamino-4 ^1- diethylaminoazobenzene (0.005 mol), 0.27 g of magnesium oxide (0.0038 mol ), 1.33 g of anhydrous sodium acetate (0.00162 mol), 1.1 ml of pyridine (0.0136 mol) and 100 ml of ethyl cellosolve at 95-105 ^{° C.} over a period of 3 hours, a solution of 1.3 ml of acetone cyanohydrin is added dropwise in 10 ml of ethyl cellosolve, heated for 2.5 h at 100-110 ^o С, cooled to 60 ^o С, volatile products were distilled off in vacuo, the residue was triturated with hot water, stirred at 40 ^o С, after treatment as in Example 2, the desired dye was obtained with out house 95% selectivity cyanidation 0.958. The dye dyes the polyester fiber with a high-temperature method in a bright pink color with a blue tint.

PRI me R s 5-15
Obtaining cyanide dyes of the formula (I) by substitution of halogen atoms in the dyes of the formula (II).

К смеси 0,01 моль бромсодержащего красителя формулы (II), 0,008 моль углекислого калия (в примерах NN 7 и 14, где вводится 2 циангруппы удвоенное количество), промотора (0,015 моль при использовании пиридина, 0,05 моль - других промоторов; в примерах 7 и 14 удвоенное количество), 0,0015 моль однохлористой меди и 200 мл этилцеллозольва при 100-110^oС за 3 ч по каплям добавляют раствор 0,0115 моль ацетонциангидрина (в примерах 7 и 14 по 0,023 моль); в 10 мл этилцеллозольва, нагревают при 100-110^oС до практически полной конверсии, аналогично примеру 2 получают красители формулы (I); данные о селективности цианирования приведены в таблице.

To a mixture of 0.01 mol of a bromine-containing dye of the formula (II), 0.008 mol of potassium carbonate (in examples NN 7 and 14, where 2 cyano groups are doubled), a promoter (0.015 mol using pyridine, 0.05 mol of other promoters; examples 7 and 14 doubled), 0.0015 mol of copper monochloride and 200 ml of ethyl cellosolve at 100-110 ^{° C.} over 3 hours, a solution of 0.0115 mol of acetone cyanohydrin is added dropwise (in examples 7 and 14, 0.023 mol); in 10 ml of ethyl cellosolve, heated at 100-110 ^o With until almost complete conversion, analogously to example 2, dyes of the formula (I) are obtained; cyanation selectivity data are given in the table.

PRI me R 16
Preparation of 2-cyano-4,6-dinitro-2 ¹ -acetylamino-4 ¹ -dibutylaminoazobenzene.

A mixture of 5.35 (0.01 mol) 2-bromo-4,6-dinitro-2 ¹ -acetylamino-4 ¹ -dibutylaminoazobenzene (as a freshly prepared aqueous paste containing 73.3% water) was suspended in 11 ml of dimethylformamide and 100 ml of water, add 0.7 g of a dispersant of a product of condensation of naphthalene sulfonic acid with formaldehyde and 0.81 g of triethylbenzylammonium chloride, 0.69 g of anhydrous sodium carbonate (0.0085 mol) and 0.3 g of copper monochloride are added to the resulting thin suspension, heated to boiling and boiling dropwise in 2 hours add a solution of 1.2 ml of acetone cyanohydrin in 25 ml of water, at the same time water and the volatile products resulting from the reaction are slowly distilled off, boiled for another 5 hours. After treatment with a mixture of 5 ml of a saturated solution of ferric chloride in 10 ml of 2% hydrochloric acid (5 hours, 35-40 ^° C), the precipitate is separated, washed with 0, 5% hydrochloric acid, water, isopropanol, diluted ammonia, hot water, dried and get the target product, yield 93% selectivity cyanidation of 0.82.

 Similarly, the same dye in a medium of 50% aqueous pyridine was obtained with a yield of 89% cyanidation selectivity of 0.91.

 Both dyes dye the polyester fiber in a bright blue color by a high-temperature method.

 As can be seen from the above examples and the table, the efficiency (selectivity) of cyanidation for the inventive cyanidating agent is 0.9-0.98, while by the known method 0.61-0.88.

 The ratio of the amount of the target cyanide-containing dye formed to the sum of the quantities of the target and by-products (determined spectrophotometrically) is taken as a measure of selectivity.

In addition, increases the yield of the target product by the present method 93-97% of the prototype 77-84%
From these data it follows that a positive effect is achieved precisely through the use of a new cyanating agent, acetone cyanohydrin.

Claims (2)

 1. A method of producing azo dyes containing cyano groups by reacting a halogen-containing azo dye with a cyanating agent in the presence of a copper catalyst and a base, characterized in that acetone cyanohydrin is used as the cyanizing agent.  2. The method according to p. 1, characterized in that the pyridine promoter, or an alkali metal halide, or a quaternary ammonium salt is additionally introduced into the reaction mass.

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