KR20140051564A - Synthetic methods of mono azo compounds and ecofriendly mono azo compounds synthesized therefrom - Google Patents

Abstract

The present invention relates to a manufacturing method of monoazo compounds and environment-friendly monoazo compounds manufactured therefrom, and to a manufacturing method of environment-friendly monoazo compounds having a low content of poly chlorinated biphenyls (PCBs), naphthol, and primary aromatic amines (PAA) which are environmentally hazardous substances, and to environment-friendly monoazo compounds manufactured therefrom. According to the manufacturing method of monoazo compounds of the present invention, by setting PCBs to be 25ppm or less, naphthol to be 1% or less, and PPA to be 500ppm or less, monoazo pigments, supplied as packing water-based ink of food packaging materials, which satisfy the recent international standards can be manufactured.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for producing a monoazo compound, and an eco-friendly monoazo compound prepared from the same. BACKGROUND ART < RTI ID = 0.0 >

The present invention relates to a method for producing a monoazo compound and an eco-friendly monoazo compound produced therefrom, and relates to an eco-friendly monoazo compound having a low content of polychlorinated biphenyls (PCBs), naphthol and primary aromatic amines Azo compounds and eco-friendly monoazo compounds prepared therefrom.

It is known that industrially produced organic pigments may contain PCBs because of the particular structural aspect of the particular organic solvent or starter component used in the synthesis of the monoazo pigment and the synthesis for removing or reducing such impurities in the pigment A method is under development.

Due to the toxicity and carcinogenic potential of PCBs, as well as to the production of these classes of compounds that are widely used in industry due to their residual and in vivo accumulation properties, the production of these compounds has ceased or a significant restriction on the distribution of formulations containing PCBs as products and impurities And control. These limitations have recently been further strengthened and have resulted in a rapid decrease in the concentration of acceptable PCBs in normal products. For example, in the United States, a maximum of 25 μg of PCB per kilogram of annual average marketed substance is prescribed.

Several documents describe a number of methods for the removal of contaminated liquids or solids from PCBs. In this method, the components of the PCBs are removed by solvent extraction or the chemical structure of the PCBs is modified to decompose or inactivate them. Other documents include, for example, a method of de-halogenating an alkali metal, an alkali metal hydroxide, an alkali metal compound of a polyalkylene glycol ether or sulfur, and a catalyzed oxidative distribution method of decomposing by heating, photolysis or by supplying electrical energy . However, since PCBs are non-reactive organic compounds, these methods are in fact difficult to remove by the particular continuous purification method of the pigments.

Nevertheless, there are many examples in which the above-described solvent treatment method is applied to organic pigments. For example, EP-B-0,063,321 describes that the treated organic pigments can be treated with a mixture of hydrophilic and hydrophobic organic solvents at 50-180 < 0 > C and converted to a high purity product, which has a limited intermixture have. In this process, the impurities accumulate in one of the organic phases. These and similar purification methods are suitable for pigments which may give rise to room for improvement in the application characteristics of the treated pigments obtained during synthesis. However, solvent treatment generally does not remove all impurities because the pigment impurities, for example, PCBs, are adsorbed on one surface of the pigment particles and the other is trapped in the agglomerates. The solvent treatment is not suitable for a pigment having a relatively low solvent resistance, such as a mozzo azo pigment having a simple structure. After synthesis, these pigments are already present in forms with desired application properties. In general, post treatment with organic solvents also has an undesirable effect on the physical properties of the monoazo pigments and their color tone characteristics. Another problem is that all purification methods including an organic solvent have a disadvantage in that cost problems are significantly increased.

Monoazo pigments contain environmental harmful factors such as naphthol and PAA in addition to the above-mentioned PCBs, and therefore, there is a need to develop a synthesis method capable of effectively reducing them.

United States Patent Registration No. US 5,086,168

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems of the prior art as described above, and a problem to be solved by the present invention is that monoazo pigments including PCBs, naphthol and PAA have been widely used for food packaging materials, Monoazo compounds that make PCBs generated from monoazo pigments less than 25ppm, naphthol less than 1%, PAA less than 500ppm, and PCBs produced from monoazo pigments, as the substance and regulatory scope become more specific and more specific, .

In order to solve the above-mentioned problems, the present invention provides a method for producing a monoazo compound, which comprises adding a diazonium salt solution to a coupling suspension and performing a coupling reaction, wherein the diazonium salt solution is subjected to micro filtration And then introduced into the coupling suspension. The present invention also provides a method for producing a monoazo compound.

The coupling suspension of the present invention preferably contains a nonionic surfactant.

The diazonium salt solution of the present invention is preferably nitrite-free.

The nitrite of the present invention is preferably removed by adding sulfonic acid to the diazonium salt solution.

The coupling reaction of the present invention is preferably carried out at pH 1-2.

The coupling reaction of the present invention is preferably carried out at 10 to 20 ° C.

Preferably, the present invention further includes a step of post-treating the mixture at a pH of 4 to 12 after the coupling reaction.

The present invention also provides a monoazo compound which is characterized by satisfying at least one concentration condition of not more than 25 ppm of PCBs (Poly Chlorinated Biphenyls) per 1 g of the monoazo compound, not more than 1 wt% of naphthol and not more than 500 ppm of PAA (Primary Aromatic Amines) ≪ / RTI >

The present invention also provides an azo pigment characterized by containing a monoazo compound of the present invention.

The azo pigment is preferably supplied for packed aqueous ink of food packaging material.

According to the method for producing a monoazo compound of the present invention, it is possible to produce a monoazo pigment supplied to a packing water-based ink of a food packaging material conforming to international standards recently, by making PCBs 25 ppm or less, naphthol 1% or less and PAA 500 ppm or less There is an effect.

Hereinafter, the present invention will be described in detail.

The inventors of the present invention have been studying a method for producing monoazo compounds containing the contents of PCBs, naphthol and PAA at a concentration lower than the concentration suitable for the use of the regulated substance, and the degree of purification of the diazonium salt introduced in the coupling reaction and the coupling reaction , The present inventors have completed the present invention by confirming the production of a monoazo compound having a content of not more than the desired content range.

Therefore, the present invention relates to a method for producing a monoazo compound, which comprises introducing a diazonium salt solution into a coupling suspension and performing a coupling reaction, wherein the diazonium salt solution is subjected to micro filtration and then introduced into the coupling suspension And a method for producing the monoazo compound.

The monoazo compound of the present invention is represented by the following formula (1).

[Chemical Formula 1]

Here, n represents an integer of 2 or 3.

The arylamine for synthesizing the monoazo compound represented by Formula 1 of the present invention may be 2,3-dichloroaniline, 2,4-dichloroaniline, 2,5-dichloroaniline, 2,6-dichloroaniline, 3,4 -Dichloroaniline, 3,5-dichloroaniline, 2,3,4-trichloroaniline, 2,3,5-trichloroaniline, 2,3,6-trichloroaniline, 2,4,5-trichloroaniline , 2,4,6-trichloroaniline or 3,4,5-trichloroaniline, preferably 2,3,4-trichloroaniline, 2,3,5-trichloroaniline, 2,3 , 6-trichloroaniline, 2,4,5-trichloroaniline, 2,4,6-trichloroaniline or 3,4,5-trichloroaniline.

The coupling component represented by X in the formula (1) for synthesizing the monoazo compound represented by the formula (1) is acetoacetarylamide or a naphthol-based CH-acid compound.

Preferred coupling components may be substituted by one or more, preferably one to three, radicals selected from the group consisting of methyl, methoxy, ethoxy, nitro and chlorine, and the 5- or 6-membered Acetoacetanilide, such as acetoacetanilide, which may have a primary heterocycle, or an acetoacetamide such as naphthol or 2-hydroxy-3-naphthoic acid and hydroxy-3-N- Which may be substituted by one or more methyl, methoxyethoxy, naphtho, alkanoylamino (e.g. acetamino), aroylamino (e.g. benzoylamino) and chlorine, 2-hydroxy-3-N-phenylnaphthanilide which may have a heterocycle of 1 to 4 carbon atoms.

The preferred coupling component is 5-acetoacetylamino-benzimidazolone or especially 2-hydroxy-3-naphthanilide, 2-hydroxy-3-N- (2- or 4- methylphenyl) , 2-hydroxy-3-N- (2-methoxyphenyl or 2-ethoxyphenyl) -naphthamide, 2-hydroxy- And 2-hydroxy-3-N-arylnaphthamide such as 5- (2-hydroxy-3-naphthoylamino) -benzamidazol-2-one.

In the microfiltration of the present invention, activated carbon having a porous, large surface area and high adsorbability is used for introducing a highly pure diazonium salt into a coupling reaction.

The coupling suspension of the present invention preferably contains a nonionic surfactant together with a coupling component. The nonionic surfactant may be, for example, dodecylammonium acetate.

The diazonium salt solution of the present invention is preferably nitrite-free. The nitrite can be removed by adding sulfonic acid to the diazonium salt solution.

The coupling reaction of the present invention is preferably carried out at pH 1 to 2 and at 10 to 20 ° C.

Preferably, the present invention further includes a step of post-treating the mixture at a pH of 4 to 12 after the coupling reaction.

According to the coupling reaction conditions as described above, it is possible to produce the desired monoazo compound of the present invention.

The present invention also provides a monoazo compound which is characterized by satisfying at least one concentration condition of not more than 25 ppm of PCBs (Poly Chlorinated Biphenyls) per 1 g of the monoazo compound, not more than 1 wt% of naphthol and not more than 500 ppm of PAA (Primary Aromatic Amines) ≪ / RTI >

Preferably, the monoazo compound of the present invention contains 25 ppm or less of PCBs (polychlorinated biphenyls), 1 wt% or less of naphthol, and 500 ppm or less of primary amorphous amines (PAA).

The monoazo compound of the present invention can be produced according to the process for producing the monoazo compound of the present invention.

The present invention also provides an azo pigment characterized by containing a monoazo compound of the present invention. The azo pigment is preferably supplied to the packing water-based ink of the food packaging material.

Hereinafter, the present invention will be described in more detail with reference to examples. The following examples illustrate specific preferred embodiments of the present invention and are not intended to limit the scope of the present invention.

[ Example ]

Example  One

In the first reaction tank, 20.4 parts of 2,4,5-trichloroaniline is added to 22% HCl in a volume ratio of 50.4parts and sufficiently dispersed for 8 hours. Add ice and adjust to -5 ~ 0 ℃. Prepare a solution by dissolving 7.3parts of acetic acid in 20 parts of water. At this time, the volume ratio of water should be adjusted to about 400 parts. The acetic acid solution is slowly added to the 2,4,5-trichloroaniline dispersion tank (10 to 20 minutes). After 2 hours, remove the remaining nitrite by a small amount of spheric acid. Remove the nitrate and filter the diazonium salt solution.

In the second reaction vessel, 28.8 parts of 3-Hydroxy-2-naphthoic-2methylanilide is added to 500 parts of water, and then 12 parts of 50% caustic soda is added and dissolved at 80 to 90 ° C. After dissolving for about 30 minutes, it is transferred to the third reaction tank after the purification process. At this time, the reaction temperature is cooled to 25 to 30 ° C to prepare the reaction.

Then the gemstone is reacted with 22% HCl in 33 parts over 60 minutes. Dodecylammonium acetate, a non-ionic surfactant, is dissolved in about 1% of the yield and added directly to the suspension. At this time, the pH is adjusted to about 2. Slowly add the diazonium solution to the Coupler suspension through the microfilter (2-3 hrs). Micro filtering is a more advanced method than the existing filtering method. In order to obtain a more pure diazonium salt, the chemical reaction is made quick by using activated carbon which is porous and has a large surface area and high adsorption ability. Pure diazonium salt is obtained twice over the course of one further purification through micro mesh filtering. The reaction pH of the diazonium solution in the Coupler suspension is between 1 and 2. After the coupling reaction, stir for a while and then heat to 90 ° C.

Check for the existence of diazonium through spot test with H acid throughout the entire coupling. When this process is completed, filter the reaction solution and dry it at 80-90 ° C.

The above semi-finished product (Pigment Red 112) was eluted with hexane, dissolved in sulfuric acid, and the substance was extracted and the content of PCBs was measured by GC-MS to be 25 ppm or less per 1 g of the sample. In addition, when the semi-product sample (Pigment Red 112) was eluted in acetonitrile and the content of naphthol was measured by HPLC, 1% or more was detected.

Example  2

In the first reaction tank, 20.4 parts of 2,4,5-trichloroaniline is added to 22% HCl in a volume ratio of 50.4parts and sufficiently dispersed for 8 hours. Add ice and adjust to -5 ~ 0 ℃. Prepare a solution by dissolving 7.3parts of acetic acid in 20 parts of water. At this time, the volume ratio of water should be adjusted to about 400 parts. The acetic acid solution is slowly added to the 2,4,5-trichloroaniline dispersion tank (10 to 20 minutes). After 2 hours, remove remaining nitrite with a small amount of sphamic acid. Remove the nitrate and micro filter the synthesized diazonium salt solution. Micro filtering is a more advanced method than the existing filtering method. In order to obtain a more pure diazonium salt, the chemical reaction is made quick by using activated carbon which is porous and has a large surface area and high adsorption ability. Pure diazonium salt is obtained twice over the course of one further purification through micro mesh filtering.

In the second reaction vessel, 28.8 parts of 3-Hydroxy-2-naphthoic-2methylanilide is added to 500 parts of water and 12 parts of 50% caustic soda is added and dissolved at 80 ~ 90 ℃. After dissolving for about 30 minutes, it is transferred to the third reaction tank after the purification process. At this time, the reaction temperature is cooled to 25 to 30 ° C to prepare the reaction.

Then the gemstone is reacted with 22% HCl in 33 parts over 60 minutes. Dodecylammonium acetate, a non-ionic surfactant, is dissolved in about 1% of the yield and added directly to the suspension. At this time, the pH is adjusted to about 2. Slowly add the diazonium solution to the Coupler suspension by microfiltering (2-3 hrs). The reaction pH of the diazonium solution in the Coupler suspension is between 1 and 2. After the coupling reaction, stir for a while and then heat to 90 ° C.

Check for the existence of diazonium through spot test with H acid throughout the entire coupling. After heating, the pH is adjusted to 4 to perform post-treatment. When this process is completed, filter the reaction solution and dry it at 80 ~ 90 ℃.

The above semi-product sample (Pigment Red 112) was eluted with Hexan, dissolved in sulfuric acid, and the substance was extracted and the content of PCBs was measured by GC-MS to be 20 ppm per 1 g of the sample. The amount of Naphthol was 2.86% when the semi-product sample (Pigment Red 112) was eluted with acetonitrile and analyzed by HPLC.

Example  3

In the first reaction tank, 20.4 parts of 2,4,5-trichloroaniline is added to 22% HCl in a volume ratio of 50.4parts and sufficiently dispersed for 8 hours. Add ice and adjust to -5 ~ 0 ℃. Prepare a solution by dissolving 7.3parts of acetic acid in 20 parts of water. At this time, the volume ratio of water should be adjusted to about 400 parts. The acetic acid solution is slowly added to the 2,4,5-trichloroaniline dispersion tank (10 to 20 minutes). After 2 hours, remove remaining nitrite with a small amount of sphamic acid. Remove the nitrate and micro filter the synthesized diazonium salt solution. Micro filtering is a more advanced method than the existing filtering method. In order to obtain a more pure diazonium salt, the chemical reaction is made quick by using activated carbon which is porous and has a large surface area and high adsorption ability. Pure diazonium salt is obtained twice over the course of one further purification through micro mesh filtering.

In the second reaction vessel, 28.8 parts of 3-Hydroxy-2-naphthoic-2methylanilide is added to 500 parts of water and 12 parts of 50% caustic soda is added and dissolved at 80 ~ 90 ℃. After dissolving for about 30 minutes, it is transferred to the third reaction tank after the purification process. At this time, the reaction temperature is cooled to 25 to 30 ° C to prepare the reaction.

Then the gemstone is reacted with 22% HCl in 33 parts over 60 minutes. Dodecylammonium acetate, a non-ionic surfactant, is dissolved in about 1% of the yield and added directly to the suspension. At this time, the pH is adjusted to about 2. Slowly add the diazonium solution to the Coupler suspension by microfiltering (2-3 hrs). The reaction pH of the diazonium solution in the Coupler suspension is between 1 and 2. After the coupling reaction, stir for a while and then heat to 90 ° C.

Check for the existence of diazonium through spot test with H acid throughout the entire coupling. After heating, the pH is adjusted to 8 to carry out a post-treatment process. When this process is completed, filter the reaction solution and dry it at 80 ~ 90 ℃.

The above semi-finished product (Pigment Red 112) was eluted with Hexan, dissolved in sulfuric acid, and the substance was extracted and the content of PCBs was measured by GC-MS to be 17.3 ppm per 1 g of the sample. In addition, when the semi-product sample (Pigment Red 112) was eluted with acetonitrile and the content of naphthol was measured by HPLC, 1.17% was detected.

Example  4

In the first reaction tank, 20.4 parts of 2,4,5-trichloroaniline is added to 22% HCl in a volume ratio of 50.4parts and sufficiently dispersed for 8 hours. Add ice and adjust to -5 ~ 0 ℃. Prepare a solution by dissolving 7.3parts of acetic acid in 20 parts of water. At this time, the volume ratio of water should be adjusted to about 400 parts. The acetic acid solution is slowly added to the 2,4,5-trichloroaniline dispersion tank (10 to 20 minutes). After 2 hours, remove remaining nitrite with a small amount of sphamic acid. Remove the nitrate and micro filter the synthesized diazonium salt solution. Micro filtering is a more advanced method than the existing filtering method. In order to obtain a more pure diazonium salt, the chemical reaction is made quick by using activated carbon which is porous and has a large surface area and high adsorption ability. Pure diazonium salt is obtained twice over the course of one further purification through micro mesh filtering.

In the second reaction vessel, 28.8 parts of 3-Hydroxy-2-naphthoic-2methylanilide is added to 500 parts of water and 12 parts of 50% caustic soda is added and dissolved at 80 ~ 90 ℃. After dissolving for about 30 minutes, it is transferred to the third reaction tank after the purification process. At this time, the reaction temperature is cooled to 25 to 30 ° C to prepare the reaction.

Then the gemstone is reacted with 22% HCl in 33 parts over 60 minutes. Dodecylammonium acetate, a non-ionic surfactant, is dissolved in about 1% of the yield and added directly to the suspension. At this time, the pH is adjusted to about 2. Slowly add the diazonium solution to the Coupler suspension by microfiltering (2-3 hrs). The reaction pH of the diazonium solution in the Coupler suspension is between 1 and 2. After the coupling reaction, stir for a while and then heat to 90 ° C.

Check for the existence of diazonium through spot test with H acid throughout the entire coupling. After heating, the pH is adjusted to 10 to carry out a post-treatment process. When this process is completed, filter the reaction solution and dry it at 80 ~ 90 ℃.

The above semi-finished product (Pigment Red 112) was eluted with hexane, dissolved in sulfuric acid, and the substance was extracted and the content of PCBs was measured by GC-MS to be 22 ppm per gram of the sample. In addition, when the content of naphthol was measured by HPLC after eluting the semi-finished product (Pigment Red 112) with acetonitrile, 0.1487% was detected.

Example  5

In the first reaction tank, 20.4 parts of 2,4,5-trichloroaniline is added to 22% HCl in a volume ratio of 50.4parts and sufficiently dispersed for 8 hours. Add ice and adjust to -5 ~ 0 ℃. Prepare a solution by dissolving 7.3parts of acetic acid in 20 parts of water. At this time, the volume ratio of water should be adjusted to about 400 parts. The acetic acid solution is slowly added to the 2,4,5-trichloroaniline dispersion tank (10 to 20 minutes). After 2 hours, remove remaining nitrite with a small amount of sphamic acid. Remove the nitrate and micro filter the synthesized diazonium salt solution. Micro filtering is a more advanced method than the existing filtering method. In order to obtain a more pure diazonium salt, the chemical reaction is made quick by using activated carbon which is porous and has a large surface area and high adsorption ability. Pure diazonium salt is obtained twice over the course of one further purification through micro mesh filtering.

In the second reaction vessel, 28.8 parts of 3-Hydroxy-2-naphthoic-2methylanilide is added to 500 parts of water and 12 parts of 50% caustic soda is added and dissolved at 80 ~ 90 ℃. After dissolving for about 30 minutes, it is transferred to the third reaction tank after the purification process. At this time, the reaction temperature is cooled to 25 to 30 ° C to prepare the reaction.

Then the gemstone is reacted with 22% HCl in 33 parts over 60 minutes. Dodecylammonium acetate, a non-ionic surfactant, is dissolved in about 1% of the yield and added directly to the suspension. At this time, the pH is adjusted to about 2. Slowly add the diazonium solution to the Coupler suspension by microfiltering (2-3 hrs). The reaction pH of the diazonium solution in the Coupler suspension is between 1 and 2. After the coupling reaction, stir for a while and then heat to 90 ° C.

Check for the existence of diazonium through spot test with H acid throughout the entire coupling. After heating, the pH is adjusted to 12 to carry out a post-treatment process. When this process is completed, filter the reaction solution and dry it at 80 ~ 90 ℃.

The above semi-finished product (Pigment Red 112) was eluted with hexane, dissolved in sulfuric acid, and the substance was extracted, and the content of PCBs was measured by GC-MS to be 51 ppm per gram of the sample. In addition, 0.0625% of the semi-product sample (Pigment Red 112) was eluted with acetonitrile and the content of naphthol was measured by HPLC. In addition, the above semi-product sample (Pigment Red 112) was eluted with ethanol by EDTA method No. 212 and further extracted with concentrated hydrochloric acid. The PAA component was detected by HPLC and found to be 16.8 ppm per 1 g of the pigment.

Comparative Example  One

In the first reaction vessel, 2,4,5-trichloroaniline of 17.5 parts is added to 22% HCl in a volume ratio of 44 parts and is thoroughly dispersed for 8 hours. Add ice and adjust to -5 ~ 0 ℃. 6.7 parts of acetic acid prepared in advance is dissolved in 20 parts of water to make a solution. At this time, the volume ratio of water should be adjusted to about 400 parts. The acetic acid solution is slowly added to the 2,4,5-trichloroaniline dispersion tank (10 to 20 minutes). After 2 hours, remove remaining nitrite with a small amount of sphamic acid. Remove the nitrate and filter the diazonium salt solution.

In the second reaction vessel, 20.7 parts of 3-Hydroxy-2-naphthoic-2methylanilide is added to 500 parts, and 12 parts of 50% caustic soda is added and dissolved at 80 ~ 90 ℃. After dissolving for about 30 minutes, it is transferred to the third reaction tank after the purification process. At this time, the reaction temperature is cooled to 10 to 15 ° C to prepare the reaction.

The next step is to react the gemstone with 22% HCl in 33 parts over 60 minutes. At this time, the appropriate pH is set to about 2 ~ 3. The diazonium solution is slowly added to the Coupler suspension through the primary filtering (2-3 hrs). The reaction pH of the diazonium solution in the Coupler suspension is between 1 and 2. After the coupling reaction, stir for a while and then heat to 90 ° C.

Check for the existence of diazonium through spot test with H acid throughout the entire coupling. When this process is completed, filter the reaction solution and dry it at 80 ~ 90 ℃.

The semi-product sample (Pigment Red 112) was eluted with hexane, dissolved in sulfuric acid, and the substance was extracted. When the content of PCBs was measured by GC-MS, it was detected to be 100 ppm or more. In addition, when the semi-product sample (Pigment Red 112) was eluted in acetonitrile and the content of PAA was measured by HPLC, 1% or more was detected.

Comparative Example  2

In the first reaction tank, 20.4 parts of 2,4,5-trichloroaniline is added to 22% HCl in a volume ratio of 50.4parts and sufficiently dispersed for 8 hours. Add ice and adjust to -5 ~ 0 ℃. Prepare a solution by dissolving 7.3parts of acetic acid in 20 parts of water. At this time, the volume ratio of water should be adjusted to about 400 parts. The acetic acid solution is slowly added to the 2,4,5-trichloroaniline dispersion tank (10 to 20 minutes). After 2 hours, remove remaining nitrite with a small amount of sphamic acid. Remove the nitrate and filter the diazonium salt solution.

In the second reaction vessel, 28.8 parts of 3-Hydroxy-2-naphthoic-2methylanilide is added to 500 parts and then 12 parts of 50% caustic soda is added and dissolved at 90-80 ° C. After dissolving for about 30 minutes, it is transferred to the third reaction tank after the purification process. At this time, the reaction temperature is cooled to 25 to 30 ° C to prepare the reaction.

The next 15parts of Aceticacid is reacted with the gemstone for 60 minutes. At this time, the appropriate pH is set to about 6. The diazonium solution is slowly added to the Coupler suspension through the primary filtering (2-3 hrs). The reaction pH of the diazonium solution in the Coupler suspension is between 4 and 7. After the coupling reaction, stir for a while and then heat to 90 ° C.

Check for the existence of diazonium through spot test with H acid throughout the entire coupling. When this process is completed, filter the reaction solution and dry it at 80 ~ 90 ℃.

The above semi-finished product (Pigment Red 112) was eluted with hexane, dissolved in sulfuric acid, and the substance was extracted, and the content of PCBs was measured by GC-MS to be 50 ppm or more. In addition, when the semi-product sample (Pigment Red 112) was eluted with acetonitrile and the content of naphthol was measured by HPLC, 1% or more was detected.

Claims (10)

A method for producing a monoazo compound in which a diazonium salt solution is added to a coupling suspension to carry out a coupling reaction, characterized in that the diazonium salt solution is introduced into the coupling suspension after micro filtration, A method for producing an azo compound. The method of claim 1, wherein the coupling suspension comprises a nonionic surfactant. The method according to claim 1, wherein the diazonium salt solution is nitrite-free. 4. The method of claim 3, wherein the nitrite is removed by adding sulfonic acid to the diazonium salt solution. 2. A process according to claim 1, wherein the coupling reaction is carried out at a pH of 1-2. The process according to claim 1, wherein the coupling reaction is carried out at 10 to 20 占 폚. 7. The process according to any one of claims 1 to 6, further comprising a step of post-treatment with a pH of 4 to 12 after the coupling reaction. Wherein the concentration of at least one of PCBs (polychlorinated biphenyls) of not more than 25 ppm, naphthol of not more than 1 wt%, and PAA (primary aromatic amines) of not more than 500 ppm per gram of the monoazo compound is satisfied. An azo pigment characterized by containing the monoazo compound of claim 8. The azo pigment according to claim 9, wherein the azo pigment is for food packaging.