WO2005021657A1

WO2005021657A1 - Nigrosine dye and process for producing the same

Info

Publication number: WO2005021657A1
Application number: PCT/JP2004/012297
Authority: WO
Inventors: Tetsuji Kihara; Kazuaki Sukata
Original assignee: Orient Chemical Industries, Ltd.
Priority date: 2003-08-28
Filing date: 2004-08-26
Publication date: 2005-03-10
Also published as: JPWO2005021657A1; JP4621591B2

Abstract

A nonpyrophoric nigrosine dye; and a process for producing the same. In particular, there is provided a nigrosine dye which providing that the aniline content measured by means of gas chromatograph fitted with a glass sample introduction part having its temperature set at 200°C is referred to as A wt.% while the aniline content measured with the temperature of sample introduction part set at 260°C is referred to as B wt.%, satisfies the relationship: B-A ≤ 0.04 wt.%. Further, there is provided a process for producing the nigrosine dye, comprising performing heat treatment of a nigrosine base having been neutralized.

Description

Specification

Nig mouth syn dye

Technical field

TECHNICAL FIELD [0001] The present invention relates to a non-pyrophoric nig mouth synth dye and a method for producing the same.

[0002] In 1867, Coupier obtained nigricin by reacting aniline with nitrobenzene in the presence of hydrochloric acid and iron (Fe) or iron chloride (FeCl2). After that, various improvements have been made based on this method (Patent Documents 1 to 5).

[0003] Despite the improvement of such a synthesis method, there is a risk that the obtained NIG-mouth syn-dye tends to spontaneously ignite, that is, to easily spontaneously ignite during storage or during transportation. Was.

[0004] As a method of suppressing the spontaneous combustion, a technique of contacting a spontaneously combustible Nig mouth syn base with a gas containing oxygen in aniline is disclosed in Patent Document 6 (Patent Document 7). I have. However, it was found that the conversion of the nigrosine dye obtained by the method disclosed in Patent Document 6 (Patent Document 7) to non-pyrophoric property was completely insufficient.

Patent document 1: U.S. Patent No. 1896244

Patent Document 2: US Patent No. 1988499

Patent Document 3: US Patent No. 4056530

Patent Document 4: German Patent No. 44406

Patent Document 5: German Patent No. 890104

Patent Document 6: US Pat. No. 4,359,577

Patent Document 7: JP-A-56-141354

Disclosure of the invention

Problems to be solved by the invention

[0005] The present invention has been made in view of the above-mentioned problems in the prior art, and an object of the present invention is to provide a non-pyrophoric Nigmouth synth dye and a method for producing the same. There is to be.

Means for solving the problem

[0006] The present inventors have conducted intensive studies to obtain non-pyrophoric nigricin, and found that there is a clear relationship between the amount of aniline in nigricin measured by gas chromatography and the pyrophoric property. I found something.

[0007] Nigguchi Shin usually contains aniline as a contaminant. The present inventors have determined the relationship between the temperature of the sample introduction part of the gas chromatograph device and the measured aniline content when the amount of aniline in Nigguchi Shin was determined by gas chromatography (hereinafter also referred to as “GC method”). We paid attention to. When the temperature of the sample inlet is below the specified temperature, there is no substantial change in the temperature of the sample inlet and the quantitative value of the aniline content in the nig mouth, and aniline present as a contaminant (hereinafter referred to as `` contaminant Is determined almost as is.

[0008] However, when the temperature of the sample introduction part exceeds the specific temperature, the quantitative value of the content of aniline in the nig mouth is gradually increased as the temperature is increased. This is thought to be due to the occurrence of aniline which is partially decomposed and released (hereinafter referred to as “free aniline”). It is considered to be related to high / low spontaneous combustion. The temperature of the sample introduction part is set to a temperature higher than the above-mentioned specific temperature and an appropriate temperature at which a sufficient amount of free aniline is generated, and the amount of free aniline is increased by subtracting the amount of impurity aniline from the amount of measured aniline. Z small is calculated.

[0009] Using a gas chromatograph equipped with a glass sample introduction unit, the content of anilin (corresponding to the content of contaminant aniline) measured at a temperature of the sample introduction unit of 200 ° C was 8% by weight. When the aniline content measured at a temperature of 260 ° C (corresponding to the total content of contaminant aniline and free aniline) is 8% by weight, the value of BA (corresponding to the content of free aniline) is As the size decreases, the pyrophoric property decreases, and the Nig Mouth Synth Dye with BA ≤ 0.04% by weight becomes non-pyrophoric. B-A≤0 for conventional nig mouth thin dye.

No 04% by weight is found.

[0010] That is, the Nigguchi syn dye of the present invention has an aniline content of A% by weight measured with a gas chromatograph with a glass sample introduction part at a temperature of the sample introduction part of 200 ° C. When the aniline content was measured at an inlet temperature of 260 ° C and the weight was 8% by weight, In this case, it is characterized in that BA ≦ 0.04% by weight.

[0011] The determination of the spontaneous combustion property of the nig-mouth dye can be performed in accordance with a predetermined UN recommendation. The Nig Mouth Synthetic Dye of the present invention is based on the UN recommendation "Recommendations on the Transport of Dangerous Goods-Testing and Criteria Manual-1st revised edition (Class 4, Test methods for self-heating substances)". In accordance with TRANSPORT OF DANGEROUSGOODS -Manual of Tests and Criteria- Third revised edition (Class4, Test method for self-heating substances) No spontaneous ignition and heat generation of 200 ° C or more will occur within the time.

[0012] The inventors of the present invention have conducted intensive studies on the cause of the generation of free aniline and the spontaneous combustion in the conventional Nig mouth syn dye, and as a result, the generation of free aniline is due to the partial decomposition of the Nig mouth syn component. Therefore, it was presumed that one of the causes of ignition was the accumulation of heat generated by partial decomposition of the nig mouth syn component. The method of the present invention for producing a nig mouth syn dye is intended to produce a nig mouth syn dye capable of reducing the amount of free aniline due to partial decomposition of the nig mouth syn component.

[0013] That is, the method of the present invention for producing a nig-mouth synth dye is a method of producing the above-mentioned nig-mouth synth dye, wherein the neutralized nig-mouth thin base is heat-treated. And

[0014] The Nig Mouth Synthetic Dye of the present invention is non-pyrophoric and therefore highly safe and easy to handle in storage and transportation. Further, according to the method for producing a nigchid synth dye of the present invention, the non-pyrophoric nigchid syndye of the present invention can be easily obtained from a conventional pyrophoric nigchid syndye.

BEST MODE FOR CARRYING OUT THE INVENTION

[0015] A more specific method for measuring the amount of aniline for specifying the Nigguchi syn dye of the present invention is not particularly limited, and the temperature of the aniline contained in the Nigguchi syn dye is set to 200 ° C. It is sufficient that the quantification can be performed with good reproducibility in both the case of C and the case of 260 ° C. 8% by weight and 3% by weight in Examples and Comparative Examples (including ananiline measured by a gas chromatograph at a glass sample inlet temperature of 200 ° C and 260 ° C, respectively) An example is a method in which the measurement was carried out.

[0016] To 0.1 lg of the precisely weighed sample, 9 ml of a mixed solvent of ethanol: cloth form = 1: 1 and an internal standard solution (0.1 lg of precisely weighed P-nitrotoluene, ethanol: cloth form = 1) were added. : 1 [volume ratio] mixed solvent prepared to make a total volume of 100 ml) 1 ml of syrup, sonicated for 20 minutes, and filtered through a 0.45 xm filter Inject Ιμΐ (microlitre) into the glass sample inlet of a gas chromatograph as shown below to quantify the amount of adiline in the sample.

[0017] The gas chromatograph device is as follows.

Gas chromatography: ΗΡ5890 (Hewlett-Packard)

Column: DB—1701 (30 m Χ 0.53 mml. D. X I. 0 μm Film) J & W¾ $ ¾

Oven: 100 ° C_260. C (10.C / min)

Injection port: Glass, 200. C or 260 ° C, split ratio 10: 1 Detector: Flame ionization detector (FID), 280 ° C

Injection volume: l / l

The column may be another column, for example, DB-5 (manufactured by J & W).

[0019] The above test for judging the spontaneous combustibility of Nig Mouth Synthetic Dye, that is, "Recommendations on the TRANSPORT OF DANGEROUSGOODS -Manual of Tests and Criteria- Third revised edition (Class4, Test method for self-heating In accordance with “substances)”, the test to keep the temperature of 140 ° C in a cubic container with a side of 10cm can be specifically performed as follows. In the Examples and Comparative Examples described later, the spontaneous ignition was determined by the spontaneous ignition test shown below.

[0020] A sample container made of stainless steel mesh having an opening of 0.053 mm and having a side of 10 cm and having an open top is filled with a sample container, and the sample container filled with the sample container is filled with the sample container. Is placed in a sample container cover that is made of stainless steel mesh with a mesh size of 0.595 mm and has an open top, and is placed in the center of the thermostat. It is made of stainless steel mesh with a mesh of 0.595 mm and suspended at a height of 15 cm, width of 15 cm, and height of 25 cm. In addition, use a thermometer (thermoelectric) so that the temperature in the center of the sample and the inside of the thermostat can be measured. Pair) is installed. Set the temperature inside the thermostat to 140 ° C, keep this temperature for 24 hours, and record the temperature of the sample continuously for 24 hours. If, within 24 hours, ignition is observed or the temperature of the sample exceeds 200 ° C, the test is stopped at that point. The time from the start of the test until ignition is recognized or the temperature of the sample reaches 200 ° C is defined as the time to ignition.

[0021] The Nig mouth synth dye of the present invention can be produced, for example, by subjecting a pyrophoric Nig mouth syn dye to a heat treatment in a solvent. More specific examples include the following manufacturing methods.

(1) Heat treatment of pyrophoric nig mouth syn dye in the presence of organic acid

[0022] By subjecting a pyrophoric nig-mouth dye to heat treatment in a solvent using an organic acid as a catalyst, the nig-mouth dye of the present invention can be obtained.

As the organic acid, an organic acid having a pKa of 0 or more is more preferable, and an organic acid having a pKa of 3 to 5 is more preferable. Particularly preferred are the aliphatic or aromatic carboxylic acids represented by the formula (1).

[0024] [Formula 1]

R— (-COOH) _n

· · · Expression (1)

[In the formula (1), R is an aliphatic group or an aromatic group. ]

[0025] Specific examples of such carboxylic acids include aliphatic carboxylic acids such as formic acid, oxalic acid, acetic acid, propionic acid, and butyric acid; and aromatic acids such as benzoic acid, phthalic acids, benzenetricarboxylic acids, and benzenetetracarboxylic acids. Carboxylic acids can be mentioned.

Among inorganic acids such as hydrochloric acid and sulfuric acid and organic acids, relatively strong acids such as organic sulfonic acids and acids (PKa <0) generally produce non-pyrophoric Nigmouth syn dyes with BA ≤ 0.04% It is difficult.

[0026] When an organic acid is used as the catalyst, the temperature of the heat treatment is preferably from 100 ° C to 250 ° C. More preferably, the temperature is 160 ° C or more and 220 ° C or less.

[0027] The heat treatment time varies depending on the nig mouth syn used as a raw material. 8 hours. If the processing time is extremely short, sufficient effects may not be obtained.

(2) Heat Treatment of Pyrophoric Nig Mouth Synthetic Dye in the Presence of Metal Oxide or Heteropolyacid

Heat treatment of a pyrophoric nigschine dye in a solvent using a metal oxide or heteropolyacid as a catalyst can provide the nigschine dye of the present invention.

[0029] The metal oxide is at least one selected from silica, alumina, silica alumina, titania, molybdenum oxide (VI), tungsten oxide (VI), and vanadium oxide (V). it can.

[0030] Further, the heteropolyacid may be HPmoWO, HPWO, HPMO, HPMO.

3 6 6 40 3 12 40 3 12 40 3 1

1 or 2 selected from W O, H PMo V〇, H SiW O, and H GeMo O

0 2 40 3 10 2 40 4 12 40 4 12 40

The above can be considered.

When a metal oxide or heteropolyacid is used as the catalyst, the temperature of the heat treatment is preferably 50 ° C. or more and 250 ° C. or less. More preferably, it is not less than 100 ° C and not more than 220 ° C.

[0032] The heat treatment time varies depending on the nig mouth syn used as a raw material, but is generally 5 to 48 hours. If the processing time is extremely short, sufficient effects may not be obtained.

(3) Heat treatment of pyrophoric nig mouth syn dye without catalyst

The nigric synth dye of the present invention can also be obtained by subjecting a pyrophoric nigric synth dye to heat treatment in a solvent without a catalyst.

[0034] The heating temperature in the absence of a catalyst is preferably from 200 ° C to 300 ° C. More preferably, it is 220 ° C or more and 250 ° C or less.

[0035] The heat treatment time varies depending on the nig mouth syn used as a raw material.

60 hours. If the processing time is extremely short, sufficient effects may not be obtained.

[0036] A pyrophoric Nig Mouth Synthetic Dye (2

) May be produced by any method, but the neutralized

(Specific examples are C 丄 Solvent Black 5, C 丄 Solvent Black 7 and their derivatives). More preferably, it is I. Solvent Black 7. According to the above UN recommendation, a pyrophoric nig-mouth thin dye (nig-mouth thin) is stored within a 10 cm-sided cubic container and maintained at a temperature of 140 ° C within 24 hours. A substance that generates either fire or heat of 200 ° C or higher.

[0037] Either of the above production methods can be performed without a solvent, but it is preferable to use a solvent from the viewpoint of the convenience of the post-treatment step and the like.

[0038] As the solvent, various solvents such as an alcohol solvent, an aromatic solvent, an aprotic polar solvent, and an amine solvent can be used, and among them, aromatic amines are suitable.

Examples of such aromatic amines include aniline, methylaniline, dimethylaniline, ethylaniline, getylaniline, o-tonolidine, m-toluidine, p-tonolidine, benzinoleamine, dibenzylamine, tribenzinoleamine, diphenylamine. , Triphenylamine, para-naphthylamine, j3-naphthylamine and the like. Among them, various substituted or unsubstituted anilines are preferred, and aniline is most preferred.

[0040] Further, in the above production method, the heat treatment can be performed under pressure.

[0041] In any of the above production methods, depending on the solvent used, the processing temperature can be increased using an autoclave.

Example

Hereinafter, the present invention will be described more specifically with reference to Examples, but the content of the present invention is not limited to these Examples. In the following description, “%” means “% by weight”.

Example 1

Commercially available neutralized nig mouth syn base, pyrophoric nig mouth syn (B-A = 0.11%) 1. Okg and aniline 2. Okg? Kunhe f At night, 10 g of drunk acid (pKa = 4.56) was calored and refluxed under air for 20 hours with stirring (the solution temperature at this time was about 190 ° C). Thereafter, it was allowed to cool to about 30 ° C., then washed twice with 1 L (liter) of a 2% Na〇H aqueous solution, and further washed with water.

[0044] GC analysis of the obtained Nigguchi syn dye after drying under reduced pressure revealed that the amount of aniline A at a sample introduction part temperature of 200 ° C was 0.21% and that of aniline at a sample introduction part temperature of 260 ° C. B was 0.24%, that is, B-Α = 0.03%. The Nig Mouth Synth Dye did not ignite after 24 hours in the pyrophoric test.

Example 2 The treatment was carried out in the same manner as in Example 1 except that the reflux treatment time was changed to 30 hours.The amount of aniline A obtained at a sample introduction part temperature of 200 ° C of the obtained nig mouth syn dye was 0.21%, and the sample introduction was performed. The aniline content B at a head temperature of 260 ° C was 0.22%, that is, B −— = 0.01%. This Nig Mouth Shin Dye did not ignite after 24 hours in the pyrophoric test

Example 3

The same treatment as in Example 1 was carried out except that 20 g of propionic acid (pKa = 4.67) was used instead of acetic acid.The amount of aniline in the obtained Nig mouth syn dye at a sample introduction part temperature of 200 ° C was obtained. A is 0.18. /. When the temperature of the sample introduction part was 260 ° C., the amount of aniline B was 0.20%, that is, B−A = 0.02%. The Nig Mouth Synth Dye did not ignite after 24 hours in the pyrophoric test.

Example 4

The same treatment as in Example 1 was performed except that 20 g of benzoic acid (pKa = 4.00) was used instead of acetic acid.The amount of aniline in the obtained Nig-mouth synthetic dye at a sample introduction part temperature of 200 ° C was used. A was 0.15%, and the amount of aniline B at a sample inlet temperature of 260 ° C was 0.18%, that is, B—A = 0.03%. The Nig Mouth Synth dye did not ignite after 24 hours in the pyrophoric test.

Example 5

The same treatment as in Example 1 was carried out except that acetic acid was replaced with 40 g of silica gel for column chromatography (manufactured by Wako Pure Chemical Industries, Ltd.) after refluxing, and the silica gel was removed by filtration. The amount of aniline A at a sample inlet temperature of 200 ° C was 0.52%, and the amount of aniline B at a sample inlet temperature of 260 ° C was 0.54%, ie, B_A = 0.02%. The Nig Mouth Synth Dye did not ignite after 24 hours in the pyrophoric test.

Example 6

The treatment was performed in the same manner as in Example 5, except that the reflux treatment time was set to 24 hours.The aniline content A at the sample introduction part temperature of 200 ° C in the obtained nig mouth syn dye was 0.63%, and the sample introduction was performed. The amount of aniline B when the part temperature is 260 ° C is 0.64%, that is, B_A = 0.01% Met. This nig-mouth dye did not ignite even after 24 hours in the above pyrophoric test. [0050] Example 7

The same treatment as in Example 5 was conducted except that 40 g of Molecular Sieves 4A (manufactured by Aldrich: silica-alumina) was used instead of silica gel. The aniline amount A was 0.31%, and the aniline amount B at the sample inlet temperature of 260 ° C was 0.33%, that is, B_A = 0.02%. This Nig Mouth Shin dye did not ignite even after 24 hours in the spontaneous combustion test.

Example 8

Treated in the same manner as in Example 6 except that 30 g of HPMOo was used instead of silica gel.

3 6 6 40

As a result, the amount of aniline A in the obtained Nig-mouth thin dye at a sample introduction temperature of 200 ° C was 0.11. /. The amount of aniline B at a sample introduction temperature of 260 ° C was 0.12. /. That is, B—A = 0.01%. The Nig Mouth Synth Dye did not ignite after 24 hours in the pyrophoric test.

Example 9

The same treatment as in Example 5 was carried out except that 40 g of HPMO V0 was used instead of silica gel.

3 10 2 40

As a result, the amount of aniline A in the obtained Nig mouth syn dye at a sample introduction temperature of 200 ° C was 0.11%, and the amount of aniline B at a sample introduction temperature of 260 ° C was 0.13%, that is, BA = 0.02%. This Nig Mouth Sin Dye can be used 24 hours after the pyrophoric test

Example 10

A mixture of 1.0 kg of pyrophoric nigric syn (B_A = 0.11%) and 1.0 kg of aniline was heat-treated in an autoclave at 220 ° C. with stirring for 48 hours.

[0054] The obtained Nigmouth syn dye was dried under reduced pressure and analyzed by GC.

The aniline amount A at 0 ° C was 0.21%, and the aniline amount B at a sample introduction temperature of 260 ° C was 0.25%, that is, B-A = 0.04%. The Nig Mouth Synth dye did not ignite after 24 hours in the pyrophoric test.

[0055] Ratio (Example 1 shown in Patent Documents 6 and 7) Air (500 ml / min) at 75 ° C. for 16 hours was blown into a mixture of Okg and aniline 2.0 kg with good agitation while spontaneously combusting the nig mouth used in Example 1. Next, this solution was dried until the volatile matter such as aniline became 1% or less, and then cooled.

When the obtained product was analyzed by GC, the amount of aniline A was 0.51 when the temperature of the GC sample introduction part was 200 ° C. /. The amount of aniline B at the sample introduction part temperature of 260 ° C was 0.63. /. That is, B—A = 0.12%. In Patent Documents 6 and 7, the obtained samples were ignited after 6.6 hours according to the above-mentioned spontaneous combustion test method in which the sample was described as non-ignitable.

[0057] Ratio (Example 2 shown in Patent Documents 6 and 7)

Air (16 lZmin [liter Z minute]) was blown at 50 to 55 ° C. for 20 hours while stirring a mixture of the pyrophoric nigricine used in Example 1 1. Okg and aniline 2. Okg with good stirring. Next, this solution was dried until the volatile matter such as aniline became 1% or less, and then cooled.

[0058] The resulting product was analyzed by GC, Anirin amount Αί or 0.44 ^_0/0 in the case of a sample injection port temperature 200 ° C, Anirin amount ί in the case of a sample guide's咅温degree 260 ° C or 0.53 ^_0/0 was Β- Α = 0. 09%. In Patent Documents 6 and 7, the obtained sampnoles are described as non-ignitable. According to the spontaneous ignition test described above, they ignited after 7.0 hours.

Comparative Example 3

The same treatment as in Example 1 was conducted except that 10 g of hydrochloric acid (pKa = _7.0) was used instead of acetic acid, and the amount of aniline A in the obtained product at a sample introduction temperature of 200 ° C was 0. When the sample introduction part temperature was 260 ° C and 47%, the amount of aniline B was 0.78%, that is, BA = 0.31%. The sample ignited after 3.5 hours.

[0060] Comparative Example 4

The same treatment as in Example 1 was carried out except that 20 g of toluenesulfonic acid (pKa = _6.5) was used instead of acetic acid.The amount of aniline in the obtained product when the temperature at the sample inlet was 200 ° C A was 0.57%, and the amount of aniline B at a sample inlet temperature of 260 ° C was 0.83%, that is, B-A = 0.26%. The sample ignited after 3.2 hours.

[0061] Comparative Example 5

The treatment was performed in the same manner as in Example 1 except that the reflux treatment time was extremely short (3 hours). In the obtained product, the amount of aniline A at a sample inlet temperature of 200 ° C is 0.220%, and the amount of aniline at a sample inlet temperature of 260 ° C is 0.26%, that is, B−Α = 0. · It was 06 ° /. The sample ignited after 13.5 hours.

[0062] Comparative Example 6

The treatment was carried out in the same manner as in Example 5 except that the reflux time was extremely short (3 hours). The amount of aniline in the obtained product at a sample introduction temperature of 200 ° C was 0.19%, The amount of aniline B at the inlet temperature of 260 ° C is 0.30. /. That is, B_A = 0.11 ° /. The sample ignited after 7.0 hours.

Table 1 summarizes the results of Examples and Comparative Examples.

[table 1]

Processing conditions

Time (hour) Example 1 0.03> 24

20 hours

Example 2 0.01> 24

30 hours

Example No

3 Sleep 0.02> 24

20 hours

Benzoic acid (organic acid)

Example 4 0.03> 24

20 hours

Silica gel (metal oxide)

关她 1 tally 5 0.02

20 hours

Silica gel (metal oxide)

关她 1 tally b 0.01

24hours

Molecular bus 4Α

关她 1 tally 7 0.02

(Metal oxide) 20 hours

1— n H ₃ PMo ₆ W ₆ O ₄₀ , c Example 8 0.01> 24

(Heteropolyacid) 24 hours

Example ■ ■ 3 " ^ινιο 10 ^v 2 ^ 40

9 0.02> 24

(Heteropolyacid) 20 hours

刁一 L 一 — f DO Example 10

0. I04> 24

(No catalyst) 48 hours

.5 <Ν 3Δ £? 7 · ν / Ο

Comparative Example 1 0.12 6.6

16 hours

fc ^ <ΗΛ 3Δ £ ^ 7 · ^, ΟΟ

Comparative Example 2 0.09 7.0

20 hours

Hydrochloric acid (pKa =-7.0)

Comparative Example 3 0.31 3.5

20 hours

Toluenesulfonic acid

Comparative Example 4 0.26 3.2

(pKa = -6.5) 20 hours

Acetic acid (organic acid)

Comparative Example 5 0.06 13.5

3 hours

Silica gel (metal oxide)

Comparative Example 6 0.11 7.0

3 hours

Claims

The scope of the claims

[I] Using a gas chromatograph equipped with a glass sample introduction section, the sample introduction section temperature was measured at 200 ° C, the anilin content was measured at 8% by weight, and the sample introduction section temperature was measured at 260 ° C. Nig mouth syn dye, characterized in that BA ≤ 0.04% by weight when the aniline content is 8% by weight.

[2] In accordance with the UN recommendation "Recommendation for the transport of dangerous goods-Recommendations for Testing and Criteria-1st revised edition (Class 4, Test method for self-heating substances)" 2. The nig mouth synth dye according to claim 1, wherein neither spontaneous ignition nor heat generation of 200 ° C or more occurs within 24 hours in a test in which the temperature is maintained at 140 ° C.

[3] The Nig mouth syn dye according to claim 1 or 2, which is obtained by heat-treating the neutralized Nig mouth syn base.

4. The nigchid synth dye according to claim 1 or 2, which is obtained by heat-treating the neutralized nigchig synbase in various solvents in the presence of an organic acid as a catalyst.

5. The nigchid synth dye according to claim 1, which is obtained by subjecting the neutralized nigchid synbase to a heat treatment in various solvents in the presence of a metal oxide as a catalyst.

6. The Nigguchi syn dye according to claim 1, which is obtained by heat-treating the neutralized Niguchi Synbase in various solvents in the presence of heteropolyacid as a catalyst.

7. The nigchid synth dye according to claim 1, which is obtained by subjecting the neutralized nigchit synbase to a heat treatment without any catalyst in various solvents.

[8] The Nig mouth syn dye according to any one of claims 4 to 7, wherein the solvent is an aniline.

[9] The Nig mouth syn dye according to any one of claims 4 to 7, wherein the solvent is aniline.

[10] The Nig mouth syn dye according to claim 4, wherein the pKa of the organic acid is 0 or more.

[II] The Nig mouth syn dye according to claim 4, wherein the organic acid has a pKa of 3 to 5.

12. The Nig mouth syn dye according to claim 11, wherein the organic acid is an aliphatic or aromatic carboxylic acid represented by the following formula (1).

[Chemical 1]

R— (-COOH) _n · · · Expression (1)

[In the formula (1), R is an aliphatic group or an aromatic group. ]

[13] The metal oxide is one or more selected from silica, alumina, silica alumina, titania, molybdenum oxide (VI), tungsten oxide (VI), and vanadium oxide (V). The nig mouth syn dye described.

[14] The above-mentioned heteropolyacid is HPMOO, HPWO, HPMO, HPMOW

3 6 6 40 3 12 40 3 12 40 3 10 2

O, H PMo V〇, H SiW O, and H GeMo O Force 1 or 2 or less

40 3 10 2 40 4 12 40 4 12 40

7. The Nig Mouth Synth Dye of claim 6 above.

[15] The nig mouth thin dye according to claim 4, wherein the temperature of the heat treatment is 100 ° C or higher and 250 ° C or lower.

16. The nigrosine dye according to claim 5, wherein the temperature of the heat treatment is from 50 ° C. to 250 ° C.

[17] The nig mouth thin dye according to claim 7, wherein the temperature of the heat treatment is 200 ° C or more and 300 ° C or less.

[18] The Nig mouth syn dye according to any one of claims 3 to 7, wherein the heat treatment is performed under pressure.

[19] The method for producing a nigmouth synth dye according to claim 1, wherein the neutralized nigrosine base is subjected to a heat treatment.

20. The method for producing a nigchid synth dye according to claim 19, wherein the heat treatment is performed in a solvent.

21. The method for producing a Nig mouth syn dye according to claim 19 or 20, wherein the heat treatment is carried out in the presence of an organic acid, a metal oxide, or a heteropoly acid as a catalyst.

22. The method for producing a nigchid synth dye according to claim 19, 20 or 21, wherein the heat treatment is performed under pressure.

23. The method for producing a nigchid synth dye according to claim 19, wherein the solvent is aniline.