JPH0356264B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improved method for producing monoazo compounds. General formula [] _{( wherein ,} When used as a disperse dye, it can dye synthetic fibers, etc., particularly polyester fibers, in a fast and clear manner. Usually, when producing this monoazo compound, the general formula [] (In the formula, X represents the same meaning as above.) A diazonium salt of 2-aminobenzthiazoles represented by the general formula [] (In the formula, R ₁ , R ₂ and R ₃ have the same meanings as above.) For example, coupling with the aniline represented by the formula in a mineral acid such as acetic acid or sulfuric acid, or in a mixture thereof This is done by However, the cake produced at this time has a high acid concentration, and although it maintains a dispersed state at low temperatures below 10°C, it is sensitive to temperature rises and changes in acid concentration, and may turn into a tar or resinous state. , which often caused problems in handling the cake. For example, the cake of the compound of the general formula [] does not inherently have good properties during sieving, and furthermore, if part of the cake becomes tar-like due to temperature rise during sieving, it may be difficult to sieve. Not only that, but the cleaning operation becomes troublesome as the cake sticks to the material.
In addition, because an excessively long period of time is required in acidic conditions, the acylamino group of the product often undergoes hydrolysis, resulting in a decrease in fastness such as sublimation fastness when used as a dye. Even if the coupling mass is neutralized with an alkaline agent such as an aqueous solution of caustic soda for the purpose of omitting acid filtration, the cake becomes tar-like or hertz-like during the neutralization process, and there is a problem that it sticks to the inner wall of the equipment. Ta. As a result of intensive studies in view of the above circumstances, the present inventors have found that the compounds of the general formulas [] and [] can be used in mineral acid solvents,
Alternatively, a coupling reaction is carried out in a mixed solvent of a mineral acid and an organic acid, and a hydrophobic organic solvent is added to the resulting reaction mass, followed by neutralization in the presence of the hydrophobic organic solvent, resulting in acid hydrolysis of the product itself. etc., and further heat the neutralized mass as it is to recover the hydrophobic organic solvent and heat-treat the cake at the same time to cause crystal transition of the cake.
It has been found that a cake with good permeability and easy handling can be obtained. Furthermore, conventionally, the steps of acidic filtration, heat treatment, and filtration were performed, but in the method of the present invention, the acidic filtration step is omitted, resulting in a significant improvement in productivity. That is, the gist of the present invention is that the general formula [] (In the formula, X represents a hydrogen atom, a chlorine atom, or a bromine atom.) A diazonium salt of 2-aminobenzthiazoles represented by the general formula [] (In the formula, R ₁ and R ₂ represent a lower alkyl group or a cyanoethyl group, and R ₃ represents a lower alkyl group or a phenyl group.) By causing a coupling reaction with a coupling component represented by the general formula [] (In the formula, X, R ₁ , R ₂ , R ₃ have the same meanings as above.) In producing the monoazo compound represented by
After coupling the diazonium salt of 2-aminobenzthiazole represented by the general formula [] with the coupling component represented by the general formula [] in a conventional manner, the resulting reaction system is combined with the general formula []. Add 0.5 to 10% by weight of a hydrophobic organic solvent to the indicated monoazo compound, neutralize it with an alkali agent in coexistence with the hydrophobic organic solvent, and then perform a heat treatment to recover the solvent and convert the crystals of the coupled product. This is a method for producing a monoazo compound, which is characterized in that it is carried out simultaneously. The present invention will be explained in more detail below. In the present invention, examples of the 2-aminobenzthiazole of the general formula [] include 2-aminobenzthiazole, 2-amino-6-chlorobenzthiazole, and 2-amino-6-brombenzthiazole. On the other hand, in the coupling component of general formula [], R ₁ and R ₂ are ethyl group, n-propyl group, iso-propyl group, n-butyl group, tert-butyl group, n-pentyl group. Examples include the lower alkyl group and the cyanoethyl group,
Examples of R ₃ include lower alkyl groups such as methyl and ethyl groups, and further examples include phenyl. Specific examples of these compounds include, for example, 3-acetylamino-N-(β-cyanoethyl)-N-ethylaniline, 3-acetylamino-N,N-diethylaniline, and 3-acetylamino-N-(β-cyanoethyl)-N-ethylaniline. -cyanoethyl)-N-(n-pentyl)aniline, 3-benzoylamino-N,N-
Diethylaniline, 3-acetylamino-N-
(β-cyanoethyl)-N-(n-propyl)aniline and the like. The reaction of the present invention can be carried out as follows.
The diazonium salt of 2-aminobenzthiazoles and the coupling component are mixed in an aqueous solution containing 5-80% (by weight) mineral acid or a mixture of mineral acid and organic acid, preferably 10-55%. Sulfuric acid and 10~
Coupling is carried out in an aqueous solution containing 30% acetic acid. A hydrophobic organic solvent is added to the resulting reaction mass. In the present invention, a hydrophobic organic solvent means an organic solvent that does not mix freely with water. in particular,
Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, isopropylbenzene, mesitylene, naphthalene, tetralin, triethylbenzene, butylbenzene, diisopyrubenzene, dodecylbenzene, methylnaphthalene, cyclohexylbenzene, cymene, decalin, dodecane, Aliphatic hydrocarbons such as cyclohexane,
Anisole, phenethole, phenyl ether,
Aromatic ethers such as benzyl ether and dimethoxybenzene, ketones such as methyl isobutyl ketone and cyclohexanone, halogens such as chloroform, carbon tetrachloride, dichloroethane, trichloroethane, tetrachloroethane, tetrachlorethylene, trichlorethylene, dichloroethylene, etc. Examples include halogenated aliphatic hydrocarbons, monochlorobenzene, dichlorobenzene, trichlorobenzene, halogenated aromatic hydrocarbons such as α-chloronaphthalene, and nitrobenzenes such as nitrobenzene and nitrotoluene. Particularly preferred are benzenes such as toluene, chlorobenzene, nitrobenzene, and O-dichlorobenzene. The amount of solvent added is 0.5-10% based on the weight of the cake to be produced.
Preferably it is 0.7-3%. A surfactant or the like may be further used in the hydrophobic organic solvent phase for the purpose of improving stirring conditions. By adding a hydrophobic organic solvent, the cake dispersed and precipitated in the coupling reaction mass is dissolved in the hydrophobic organic solvent phase and separated into two phases: a mineral acid aqueous solution phase or a mineral acid and acetic acid mixture aqueous solution phase. To separate. In this state, it can be easily neutralized with an alkaline agent such as an aqueous solution of caustic soda. Since the cake is dissolved in a hydrophobic organic solvent, it will not become tar-like or Hertzian-like, and since it is separated from the aqueous phase, it will not undergo acid or alkaline hydrolysis. The obtained compound of general formula [] is then subjected to heat treatment. This operation causes a dislocation from an amorphous crystal system to a definite stable crystal system. This can be confirmed from the results of X-ray diffraction (see Figures 1 and 2) or melting point measurement. Furthermore, the supercharacteristics of the rearranged crystal cake are significantly improved, and in addition, when used as a disperse dye, the dyeing properties are improved, such as high temperature cohesion, dispersion stability of liquid products, and adhesion to dyeing equipment during the dyeing process. This eliminates contamination and the like, and the quality is considerably improved. The conditions for heat treatment in the present invention are 50 to 100°C, preferably 75 to 100°C. More preferable conditions vary depending on the hydrophobic organic solvent used, but for example, when chlorobenzene is used, the temperature is 90 to 95°C, when nitrobenzene is used, it is 95 to 100°C, and when toluene is used, it is 83 to 95°C. °C is appropriate. After the heat treatment, the compound of general formula [] is isolated or used without isolation by a conventional method. Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. In the examples, parts and % represent parts by weight and % by weight unless otherwise specified. Example 1 3-acetylamino-N-(β
-cyanoethyl)-N-ethylaniline 11.6 parts,
Add 30 parts of acetic acid, cool to -5 to 5°C, and add 2
- under stirring of 150 parts of 75% sulfuric acid containing 14.7 parts of diazotide of amino-6-chlorobenzthiazole,
The mixture was added dropwise for 2 hours, and after the addition was completed, stirring was continued for 30 minutes to carry out the reaction. Furthermore, 21.4 parts of chlorobenzene was added, and the mixture was neutralized with a 28% caustic soda aqueous solution. After confirming that the pH is 6-8, heat and raise the temperature to 90-95℃.
It was kept at the same temperature for 3 hours. Water distilled out at this time -
The chlorobenzene azeotrope was separated, the upper aqueous phase was returned to the heat treatment system, and the lower chlorobenzene phase was recovered. After the heat treatment was completed, the dye cake was filtered, the properties of the cake were observed, the dye cake was washed and dried, and the yield was measured, and the results shown in Table 1 were obtained. Examples 2 to 9 Similar reactions were conducted in the method of Example 1 except that the diazonium salt, aniline component, hydrophobic organic solvent, and surfactant were changed as shown in Table 1. The results are shown in Table 1. Comparative Examples 1 to 5 The same reaction as in Example 1 was carried out by changing the diazonium salt, aniline component, hydrophobic organic solvent, and surfactant as shown in Table 1.
The results are shown in Table 1.

【table】

【table】 [Brief explanation of drawings]

FIG. 1 is an X-ray diffraction diagram of the dye after crystal transition obtained in Example 1 of the present invention, and FIG. 2 is an X-ray diffraction diagram of the dye obtained according to Comparative Example 1 without undergoing crystal transition. It is a diffraction diagram.

Claims (1)

[Claims] 1. General formula [] (In the formula, X represents a hydrogen atom, a chlorine atom, or a bromine atom.) A diazonium salt of 2-aminobenzthiazoles represented by the general formula [] (In the formula, R ₁ and R ₂ represent a lower alkyl group or a cyanoethyl group, and R ₃ represents a lower alkyl group or a phenyl group.) By reacting with a coupling component represented by the general formula [] (In the formula, X, R ₁ , R ₂ , R ₃ have the same meanings as above.) In producing the monoazo compound represented by
A diazonium salt of 2-aminobenzthiazole represented by the general formula [] and a coupling component represented by the general formula [] are coupled in a conventional manner, and then the resulting reaction system is combined with the general formula [] Add 0.5 to 10% by weight of a hydrophobic organic solvent to the monoazo compound represented by the formula, neutralize it with an alkali agent in a coexistence system with the hydrophobic organic solvent, and then recover the solvent and convert the coupling product by heat treatment. A method for producing a monoazo compound, characterized by carrying out the following simultaneously.