CN115073934B - A kind of benzisothiazole heterocyclic azo dye and preparation method thereof - Google Patents

Abstract

The invention belongs to the technical field of chemical synthesis, and particularly relates to benzisothiazole heterocyclic azo dye and a preparation method thereof. The preparation method comprises the following steps: carrying out condensation reaction on acetic anhydride or benzoyl chloride and amino naphthol disulfonic acid or amino naphthol sulfonic acid to obtain a condensation product; dropwise adding sodium nitrite into concentrated sulfuric acid under the ice salt bath condition, stirring, heating until the sodium nitrite is completely dissolved to prepare nitrosylsulfuric acid, cooling, gradually adding 3-amino-5-nitrobenzoisothiazole, and stirring for reaction to obtain 3-amino-5-nitrobenzoisothiazole diazonium salt; gradually dripping 3-amino-5-nitrobenzoisothiazole diazonium salt into a condensation product for coupling reaction, adding acetate solid in batches for salting out after the reaction is completed, carrying out suction filtration, airing a filter cake to obtain a crude product, regulating the pH value after redissolving the crude product, and carrying out salting out again to obtain the benzisothiazole heterocyclic azo dye. The heterocyclic azo acid dye has the advantages of simple synthesis process, high pH sensitivity, good selectivity and reversible color change.

Description

A kind of benzisothiazole heterocyclic azo dye and preparation method thereof

Technical Field

The invention belongs to the technical field of chemical synthesis, and specifically relates to a benzisothiazole heterocyclic azo dye and a preparation method thereof.

Background technique

Azo dyes are a very important category of dyes due to their readily available raw materials, simple synthesis methods, complete chromatograms and high absorption coefficients. Many monoazo water-soluble dyes often show different color differences in different acid-base environments because the azo bond is prone to tautomerism of azo-quinonehydrazone. Research on the acid-base color change effect of such azo dyes has also become a research hotspot in the field of functional dyes. 3-Amino-5-nitrobenzisothiazole has a good dark color effect due to the presence of highly electronegative sulfur atoms and nitrogen atoms in its heterocyclic structure, the good electron transfer ability of the heterocyclic system and the strong electron-withdrawing effect of the nitro substituent. It is often used as a diazo component for synthesizing non-water-soluble dyes such as high-performance disperse dyes. However, this type of structure has poor water solubility and cannot be used in water-soluble dyes, which greatly limits the application of the excellent performance of the heterocyclic structure of 3-amino-5-nitrobenzisothiazole in the dye field.

Therefore, the present invention utilizes the good dark color effect of the heterocyclic structure of 3-amino-5-nitrobenzisothiazole, takes it as the diazo component of synthesizing water-soluble azo dyes, introduces it into the parent structure of aminonaphthol sulfonic acid water-soluble dyes, and prepares a water-soluble heterocyclic azo type acid-base color-changing dye with high pH sensitivity, good selectivity and reversible color change.

Summary of the invention

In view of the shortcomings of the prior art, the present invention provides a benzisothiazole heterocyclic azo dye and a preparation method thereof, so as to solve the problem that the 3-amino-5-nitrobenzisothiazole heterocyclic structure is difficult to be applied to water-soluble dyes, and broaden the application of the 3-amino-5-nitrobenzisothiazole heterocyclic structure in the field of dyes.

In order to achieve the above object, the present invention adopts the following technical scheme: a benzisothiazole heterocyclic azo dye having a structure of general formula I:

Wherein, n = 1 or 2;

X is selected from _-OCH3 or -OPh.

A further technical solution of the present invention is that in the formula I, the aminonaphthol disulfonic acid residue or aminonaphthol sulfonic acid residue connected to X and the azo bond is selected from one of the following groups:

H acid residue, its structural formula is:

K acid residue, its structural formula is:

Chicago acid residue, its structural formula is:

J acid residue, its structural formula is:

Gamma acid residue, its structural formula is:

A method for preparing a benzisothiazole heterocyclic azo dye, the preparation method comprising:

1) Condensation reaction

Condensation reaction is performed on acetic anhydride or benzoyl chloride and aminonaphthol disulfonic acid or aminonaphthol sulfonic acid to obtain a condensation product;

2) Diazotization reaction

In an ice-water bath, sodium nitrite is added dropwise to concentrated sulfuric acid, stirred and heated until completely dissolved to obtain nitrosyl sulfuric acid, and after cooling, 3-amino-5-nitrobenzisothiazole is gradually added, stirred and reacted to obtain 3-amino-5-nitrobenzisothiazole diazonium salt;

3) Coupling reaction

The 3-amino-5-nitrobenzisothiazole diazonium salt obtained in step 2) is gradually dripped into the condensation product in step 1) to carry out coupling reaction. After the reaction is completed, acetate solid is added in batches for salting out, filtered, and the filter cake is dried to obtain a crude product. The crude product is redissolved and the pH value is adjusted, and salting out is carried out again to obtain a benzisothiazole heterocyclic azo dye.

According to a further technical solution of the present invention, in step 1), the aminonaphthol disulfonic acid is one of H acid, K acid and Chicago acid;

Or, the aminonaphthol sulfonic acid is one of J acid and γ acid;

Or, the molar ratio of the acetic anhydride or benzoyl chloride to aminonaphthol sulfonic acid is 2.5:1;

Alternatively, the reaction temperature is 60-80°C.

According to a further technical solution of the present invention, the diazotization reaction in step 2) uses nitrosyl sulfuric acid as a diazotization reagent;

Or, the molar ratio of sodium nitrite to 3-amino-5-nitrobenzisothiazole is 1.05:1;

Or, the molar ratio of concentrated sulfuric acid to 3-amino-5-nitrobenzisothiazole is 11:1

Or, the reaction time is 2 to 4 hours;

Alternatively, the reaction temperature is 0-5°C.

A further technical solution of the present invention is that in step 3),

The molar ratio of the 3-amino-5-nitrobenzisothiazole diazonium salt to the condensation product of acetic anhydride or benzoyl chloride and aminonaphthol disulfonic acid or aminonaphthol sulfonic acid is 1:1;

Or, the reaction pH is 1 to 2;

Alternatively, the reaction temperature is 0-5°C.

According to a further technical solution of the present invention, the condensation reaction of acetic anhydride or benzoyl chloride with aminonaphthol disulfonic acid or aminonaphthol sulfonic acid in step 1) is carried out according to the following method: acetic anhydride or benzoyl chloride is added dropwise to an aqueous solution of aminonaphthol disulfonic acid or aminonaphthol sulfonic acid, wherein the molar ratio of acetic anhydride or benzoyl chloride to aminonaphthol sulfonic acid is 2.5:1; the temperature is raised to 60-80° C. and stirred for reaction, and the reaction end point is determined by detecting with an Ehrlich reagent to obtain a condensation product of acetic anhydride or benzoyl chloride and aminonaphthol disulfonic acid or aminonaphthol sulfonic acid.

A further technical solution of the present invention, the diazotization reaction in the step 2) is specifically as follows: under an ice-water bath condition of 0 to 5°C, solid sodium nitrite is gradually added to concentrated sulfuric acid, stirred, heated until completely dissolved, cooled to 0 to 5°C, and 3-amino-5-nitrobenzisothiazole is gradually added, wherein the molar ratio of sodium nitrite to 3-amino-5-nitrobenzisothiazole is 1.05:1, and the molar ratio of concentrated sulfuric acid to 3-amino-5-nitrobenzisothiazole is 11:1, and the reaction is stirred for 2 to 4 hours. After the reaction is completed, a small amount of aminosulfonic acid is added to remove excess nitrous acid to obtain 3-amino-5-nitrobenzisothiazole diazonium salt.

According to a further technical solution of the present invention, the coupling reaction in step 3) is specifically as follows: gradually dripping 3-amino-5-nitrobenzisothiazole diazonium salt into the condensation product of acetic anhydride or benzoyl chloride and aminonaphthol disulfonic acid or aminonaphthol sulfonic acid, wherein the molar ratio of 3-amino-5-nitrobenzisothiazole diazonium salt to the condensation product of acetic anhydride or benzoyl chloride and aminonaphthol disulfonic acid or aminonaphthol sulfonic acid is 1:1, controlling the pH value to be 1-2, reacting at 0-5°C, after the reaction is completed, adding a pH buffer according to a buffer mass to solution volume ratio of 1%, then adding potassium acetate solid in batches, and detecting the salting out of the dye by the infiltration circle method, stirring and then standing, suction filtering, and air-drying the filter cake to obtain a crude product, and adjusting the pH of the crude product to 6.8-7.0 after redissolving, and re-salting out to obtain a benzisothiazole heterocyclic azo dye.

The benefits of a benzisothiazole heterocyclic azo dye and a preparation method thereof: The heterocyclic azo water-soluble acid dye prepared by the present invention has a simple synthesis process, high pH sensitivity, good selectivity, and reversible color change. It not only has the dark color effect brought by the 3-amino-5-nitrobenzisothiazole heterocyclic structure, but also has water solubility and excellent acid-base color change performance, thereby broadening the application of the 3-amino-5-nitrobenzisothiazole heterocyclic structure in the field of dyes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is an infrared spectrum of a benzisothiazole heterocyclic azo dye according to Example 1 of the present invention;

FIG. 2 is a UV-visible absorption spectrum of the benzisothiazole heterocyclic azo dye of Example 1 of the present invention under different pH conditions.

Detailed ways

The specific implementation manner will be further described below in conjunction with the accompanying drawings.

The reagents and instruments in the following examples are all conventional experimental reagents and instruments.

Embodiment 1:

The specific structure of the benzisothiazole heterocyclic azo dye is as follows:

Preparation method of benzisothiazole heterocyclic azo dye:

Diazotization reaction: 11.0g concentrated sulfuric acid (0.11mol, 98%) was placed in a three-necked flask, cooled in an ice-water bath at 0-5°C, and then 0.73g sodium nitrite solid (0.0105mol) was gradually added. After stirring for a period of time, the mixture was heated until all the mixture was dissolved and the solution became clear and transparent. The heating was stopped, the mixture was cooled, and then 2.01g 3-amino-5-nitrobenzisothiazole (0.01mol, 97%) was gradually added. The mixture was stirred and reacted at 0-5°C. The reaction end point was detected by thin layer chromatography. After the reaction was completed, a small amount of aminosulfonic acid was added to remove excess nitrous acid.

Condensation reaction: take an aqueous solution containing 4.0g of H acid monosodium salt (0.01mol, 85.6%), gradually add 0.25mol of acetic anhydride according to the molar ratio of acetic anhydride to H acid of 2.5:1, heat to 60-80°C and stir to react, use Ehrlich reagent to detect and determine the reaction end point, and obtain the condensation product of acetic anhydride and H acid;

Coupling reaction: gradually drip the above 3-amino-5-nitrobenzisothiazole diazonium salt into the condensation product, control the pH value between 1 and 2, react at 0 to 5°C, and detect the reaction by the seepage circle method. After the reaction is completed, add 1% (w/v) pH buffer, add potassium acetate solid in batches, and detect the salting out of the dye by the seepage circle method. After stirring, let it stand, filter it with suction, and wash it with an appropriate amount of ethanol for 3 times. Dry the filter cake to obtain a crude product. After the crude product is redissolved, adjust the pH value to 6.8 to 7.0, and redissolve the dye Dye1.

Determine the UV-visible absorption spectra of dye solutions at different pH values:

Accurately weigh 0.1000g of dye benzisothiazole heterocyclic azo dye, add appropriate amount of deionized water to dissolve, adjust pH value to neutral with dilute hydrochloric acid or sodium carbonate solution, transfer to 100mL volumetric flask, add deionized water to scale, fix volume, and shake well. From the above-mentioned 100mL volumetric flask, respectively transfer a certain volume of dye liquor to a colorimetric tube, respectively prepare solutions of different pH values containing dye Dye1, pH values are 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, respectively, measure the UV-visible absorption spectrum of the dye solution under different pH, the result is as shown in Figure 2.

Embodiment 2:

The specific structure of the benzisothiazole heterocyclic azo dye is as follows:

Diazotization reaction: the same as the preparation in Example 1;

Condensation reaction: take an aqueous solution containing 4.0g of H acid monosodium salt (0.01mol, 85.6%), gradually add 0.25mol of benzoyl chloride according to the molar ratio of benzoyl chloride to H acid of 2.5:1, heat to 60-80℃ and stir to react, use Ehrlich reagent to detect and determine the reaction end point, and obtain the condensation product of benzoyl chloride and H acid;

Coupling reaction: The same as the preparation in Example 1, after the reaction is completed, potassium acetate is added to precipitate the dye, filtered, the crude product is redissolved and the pH value is adjusted to 6.8-7.0, and the product is salted out.

Embodiment 3:

The specific structure of the benzisothiazole heterocyclic azo dye is as follows:

Diazotization reaction: the same as the preparation in Example 1;

Condensation reaction: K acid was used instead of H acid in the preparation of the condensation product, and the other reactants and reaction conditions were the same as those in the preparation of Example 1 above;

Coupling reaction: The same as the preparation in Example 1, after the reaction is completed, potassium acetate is added to precipitate the dye, filtered, the crude product is redissolved and the pH value is adjusted to 6.8-7.0, and the product is salted out.

Embodiment 4:

The specific structure of the benzisothiazole heterocyclic azo dye is as follows:

Diazotization reaction: the same as the preparation in Example 1;

Condensation reaction: K acid was used instead of H acid in the preparation of the condensation product, and the other reactants and reaction conditions were the same as those in the preparation of Example 2 above;

Coupling reaction: The same as the preparation in Example 1, after the reaction is completed, potassium acetate is added to precipitate the dye, filtered, the crude product is redissolved and the pH value is adjusted to 6.8-7.0, and the product is salted out.

Embodiment 5:

The specific structure of the benzisothiazole heterocyclic azo dye is as follows:

Diazotization reaction: the same as the preparation in Example 1;

Condensation reaction: Chicago acid was used instead of H acid in the preparation of the condensation product, and the other reactants and reaction conditions were the same as those in the preparation of Example 1 above;

Coupling reaction: The same as the preparation in Example 1, after the reaction is completed, potassium acetate is added to precipitate the dye, filtered, the crude product is redissolved and the pH value is adjusted to 6.8-7.0, and the product is salted out.

Embodiment 6:

The specific structure of the benzisothiazole heterocyclic azo dye is as follows:

Diazotization reaction: the same as the preparation in Example 1;

Condensation reaction: Chicago acid was used instead of H acid in the preparation of the condensation product, and the other reactants and reaction conditions were the same as those in the preparation of Example 2 above;

Coupling reaction: The same as the preparation in Example 1, after the reaction is completed, potassium acetate is added to precipitate the dye, filtered, the crude product is redissolved and the pH value is adjusted to 6.8-7.0, and the product is salted out.

Embodiment 7:

The specific structure of the benzisothiazole heterocyclic azo dye is as follows:

Diazotization reaction: the same as the preparation in Example 1;

Condensation reaction: In the preparation of the condensation product, J acid is used instead of H acid, and the other reactants and reaction conditions are the same as those in the preparation of Example 1 above;

Coupling reaction: The same as the preparation in Example 1, after the reaction is completed, potassium acetate is added to precipitate the dye, filtered, the crude product is redissolved and the pH value is adjusted to 6.8-7.0, and the product is salted out.

Embodiment 8:

The specific structure of the benzisothiazole heterocyclic azo dye is as follows:

Diazotization reaction: the same as the preparation in Example 1;

Condensation reaction: In the preparation of the condensation product, J acid is used instead of H acid, and the other reactants and reaction conditions are the same as those in the preparation of Example 2 above;

Coupling reaction: The same as the preparation in Example 1, after the reaction is completed, potassium acetate is added to precipitate the dye, filtered, the crude product is redissolved and the pH value is adjusted to 6.8-7.0, and the product is salted out.

Embodiment 9:

The specific structure of the benzisothiazole heterocyclic azo dye is as follows:

Diazotization reaction: the same as the preparation in Example 1;

Condensation reaction: γ acid was used instead of H acid in the preparation of the condensation product, and the other reactants and reaction conditions were the same as those in the preparation of Example 1 above;

Coupling reaction: The same as the preparation in Example 1, after the reaction is completed, potassium acetate is added to precipitate the dye, filtered, the crude product is redissolved and the pH value is adjusted to 6.8-7.0, and the product is salted out.

Embodiment 10:

The specific structure of the benzisothiazole heterocyclic azo dye is as follows:

Diazotization reaction: the same as the preparation in Example 1;

Condensation reaction: γ acid was used instead of H acid in the preparation of the condensation product, and the other reactants and reaction conditions were the same as those in the preparation of Example 2 above;

Coupling reaction: The same as the preparation in Example 1, after the reaction is completed, potassium acetate is added to precipitate the dye, filtered, the crude product is redissolved and the pH value is adjusted to 6.8-7.0, and the product is salted out.

The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable ordinary technicians in the field to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made based on the essence of the content of the present invention should be included in the protection scope of the present invention.

Claims (7)

1. A benzisothiazole heterocyclic azo dye characterized by having the structure:

2. a process for the preparation of a benzisothiazole heterocyclic azo-type dye as described in claim 1, characterized in that the process comprises:

1) Condensation reaction

Carrying out condensation reaction on acetic anhydride or benzoyl chloride and amino naphthol disulfonic acid or amino naphthol sulfonic acid to obtain a condensation product;

2) Diazotisation reaction

Dropwise adding sodium nitrite into concentrated sulfuric acid under the ice water bath condition, stirring, heating until the sodium nitrite is completely dissolved to prepare nitrosylsulfuric acid, cooling, gradually adding 3-amino-5-nitrobenzoisothiazole, and stirring for reaction to obtain 3-amino-5-nitrobenzoisothiazole diazonium salt;

3) Coupling reaction

Gradually dripping the 3-amino-5-nitrobenzoisothiazole diazonium salt obtained in the step 2) into the condensation product obtained in the step 1) for coupling reaction, adding acetate solid in batches after the reaction is completed for salting out, carrying out suction filtration, airing a filter cake to obtain a crude product, regulating the pH value after redissolving the crude product, and carrying out salting out again to obtain the benzisothiazole heterocyclic azo dye;

in the step 1), the amino naphthol disulfonic acid is one of H acid, K acid and chicago acid;

the amino naphthol sulfonic acid is one of J acid and gamma acid;

the molar ratio of the acetic anhydride or benzoyl chloride to the amino naphthol sulfonic acid is 2.5:1;

the reaction temperature is 60-80 ℃.

3. The method for preparing benzisothiazole heterocyclic azo dye according to claim 2, wherein the diazotization reaction in the step 2) adopts nitrosylsulfuric acid as diazotizing agent;

the molar ratio of the sodium nitrite to the 3-amino-5-nitrobenzoisothiazole is 1.05:1;

the molar ratio of the concentrated sulfuric acid to the 3-amino-5-nitrobenzoisothiazole is 11:1;

the reaction time is 2-4 h;

the reaction temperature is 0-5 ℃.

4. The process for preparing benzisothiazole heterocyclic azo dyes as claimed in claim 2, wherein in the step 3),

the molar ratio of the 3-amino-5-nitrobenzoisothiazole diazonium salt to the condensation product of acetic anhydride or benzoyl chloride and amino naphthol disulfonic acid or amino naphthol sulfonic acid in the step 1) is 1:1;

the pH value of the reaction is 1-2, and the reaction temperature is 0-5 ℃.

5. The process for preparing benzisothiazole heterocyclic azo type dye according to claim 2, wherein the condensation reaction of acetic anhydride or benzoyl chloride and aminonaphthol disulfonic acid or aminonaphthol sulfonic acid in the step 1) is carried out as follows: dropwise adding acetic anhydride or benzoyl chloride into an aqueous solution of amino naphthol disulfonic acid or amino naphthol sulfonic acid, wherein the molar ratio of the acetic anhydride or benzoyl chloride to the amino naphthol sulfonic acid is 2.5:1; heating to 60-80 deg.c, stirring to react, and detecting with ehrling reagent to determine the end point of the reaction to obtain the condensation product of acetic anhydride or benzoyl chloride and amino naphthol disulfonic acid or amino naphthol sulfonic acid.

6. The method for preparing benzisothiazole heterocyclic azo dye according to claim 2, wherein the diazotization reaction in the step 2) is specifically: gradually adding sodium nitrite solid into concentrated sulfuric acid under the ice water bath condition of 0-5 ℃, stirring, heating to be completely dissolved, cooling to 0-5 ℃, gradually adding 3-amino-5-nitrobenzoisothiazole, wherein the molar ratio of sodium nitrite to 3-amino-5-nitrobenzoisothiazole is 1.05:1, the molar ratio of concentrated sulfuric acid to 3-amino-5-nitrobenzoisothiazole is 11:1, stirring and reacting for 2-4 hours, and adding a small amount of sulfamic acid to remove excessive nitrous acid after the reaction is completed, thus obtaining the 3-amino-5-nitrobenzoisothiazole diazonium salt.

7. The process for the preparation of benzisothiazole heterocyclic azo dyes according to claim 2, wherein the coupling reaction in step 3) is specifically: gradually dripping 3-amino-5-nitrobenzoisothiazole diazonium salt into condensation products of acetic anhydride or benzoyl chloride and amino naphthol disulfonic acid or amino naphthol sulfonic acid, wherein the molar ratio of the 3-amino-5-nitrobenzoisothiazole diazonium salt to the condensation products of the acetic anhydride or benzoyl chloride and the amino naphthol disulfonic acid or amino naphthol sulfonic acid in the step 1) is 1:1, controlling the pH value to be 1-2, controlling the temperature to be 0-5 ℃, adding a pH value buffer agent according to the mass-volume ratio of the buffer agent to the solution to be 1% after the reaction is finished, then adding potassium acetate solid in batches, detecting the salting-out condition of the dye by a ring permeation method, standing after stirring, carrying out suction filtration, airing a filter cake to obtain a crude product, and regulating the pH value to be 6.8-7.0 after redissolving the crude product, and carrying out salting-out again to obtain the benzisothiazole heterocyclic azo dye.