JPS5835498B2 - Method for producing nitroanthraquinone - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides industrially advantageous nitroanthraquinones, particularly 1
-Regarding a method for producing nitroanthraquinone.

More specifically, the present invention involves reusing part or all of the recovered mixed acid when nitrating anthraquinone in a mixed acid to produce nitroanthraquinone, and reducing the nitrous acid content in the nitrated mixed acid to 1% by weight or less. This is a method for producing nitroanthraquinone, which is characterized in that the reaction is carried out using:

It is known to nitrate anthraquinone in a mixed acid to obtain nitroanthraquinone.

For example, according to Japanese Patent Application Laid-Open No. 47-4784, 70 to 90
A method for obtaining 1-nitroanthraquinone by nitration with nitric acid in % sulfuric acid is described, and also in JP-A-48-4076.
Publication No. 1 describes a method for producing dinitroanthraquinone in a mixed acid.

Nitration using a mixed acid is considered to be superior in terms of economy, safety, and operation compared to other nitration methods, such as methods carried out in concentrated nitric acid, but it is desirable to carry out this method even more advantageously industrially. To this end, it is extremely important to recover and reuse the waste acid produced by the nitration reaction in terms of wastewater treatment, consumption of sulfuric acid and nitric acid, and other aspects.

However, it has been found that when the recovered mixed acid is reused as it is for the nitration reaction, various problems occur such as a decrease in the rate of the nitration reaction, a change in crystallinity, and a decrease in the yield.

As a result of intensive research and examination to determine the cause of the above-mentioned draffle, the present inventors discovered that the main cause was nitrous acid, a by-product of the nitration reaction, which was mixed in the recovered mixed acid, and completed the present invention. I ended up doing it.

That is, 2) when the recovered mixed acid is repeatedly used in the p-conversion reaction, the by-product nitrous acid accumulates, which significantly inhibits the promotion of the nitration reaction; It has been found that an excessive amount of L. has an adverse effect on the crystals of the target material, particularly making the crystals of the target product fine, and that an excessive amount of L. significantly reduces the separation efficiency.

(See Reference Example 1) As a result of further detailed study, the present inventors found that the above-mentioned troubles become extremely noticeable when the content of nitrous acid in the nitrated mixed acid exceeds a certain range, that is, 1% by weight. I understand.

In other words, it has been found that if the nitrite reaction is carried out while the nitrous acid content is always kept within a certain range, the above-mentioned troubles are substantially completely resolved and the desired nitration reaction can be carried out conveniently.

In the nitration reaction of anthraquinone with a mixed acid,
Although it depends on the reaction conditions, it is usually 0,
1 to 1.0% by weight of nitrous acid is produced as a by-product.

Therefore, if it is repeatedly used as a nitrated mixed acid without removing it, 1% by weight or more of nitrous acid will inevitably accumulate and coexist in the mixed acid.

The important point of the present invention is that in such cases, the nitrite of anthraquinone can be nitrated very efficiently by performing a simple operation of removing the nitrous acid content to 1% by weight or less based on the nitrated mixed acid. The aim is to achieve this in an industrially advantageous manner.

The present invention will be explained in more detail below.

The nitrated mixed acid used in the nitration reaction in the present invention is
When obtaining 1-nitroanthraquinone, the concentration is 70 to 100%, preferably 70 to 90%, excluding nitric acid.
%, more preferably 70 to 80%, and nitric acid in an excess molar ratio to the anthraquinone.

Further, when obtaining dinitroanthraquinone, it is desirable to have a composition consisting of sulfuric acid with a concentration of 80% or more, preferably 90% or more when excluding nitric acid, and nitric acid in an excess molar ratio to anthraquinone.

The theoretical consumption amount of nitric acid is 1 mole for mononitration and 2 moles for dinitration per 1 mole of anthraquinone, but in the above nitration mixed acid concentration, an excess molar ratio, that is, twice or more of the theoretical consumption amount is preferably used. It will be done.

In addition, the initial mixed acid amount of sulfuric acid, nitric acid, and water used in the present invention is 2.5 parts by weight per 1 part by weight of anthraquinone.
~100 parts by weight, preferably 7 to 20 parts by weight.

The reaction temperature is from -20°C to 100°C, preferably from 30 to 8°C.
It is 0°C.

In the production of 1-nitroanthraquinone, the patent application
The effects of the present invention are even more pronounced when nitration is carried out by the method described in No. 2-695.

That is, in a nitrated mixed acid having a composition consisting of 70 to 76% sulfuric acid and nitric acid in an amount such that the ratio of pure nitric acid to the total acid content is in the range of 33 to 55%, anthraquinone is extracted at a temperature of 30 to 80°C. It is appropriate to nitrate.

The nitration reaction is carried out until at least 50% or more of the anthraquinone charged is reacted.

In particular, since it is difficult to separate and remove unreacted anthraquinone remaining in the crude nitroanthraquinone mixture, it is desirable to carry out the reaction until 90% or more of the anthraquinone has reacted.

Once the nitration is complete, the reaction is quenched by cooling the reaction mixture, distilling the nitric acid under reduced pressure, or adding water, dilute nitric acid, dilute sulfuric acid, or a mixture thereof to the reaction mixture, or any suitable combination of these operations. make it stop.

The former two methods are advantageous when considering the cyclical use of mixed acids, and the crystals formed due to the addition of a diluent are generally fine and tend to worsen the p-permanence.

Next, the crude nitroanthraquinone mixture is separated from the mixed acid by a separation operation such as filtering or centrifugal sedimentation.

The obtained recovered mixed acid is subjected to appropriate nitrous acid removal treatment, and then all or part of it is used for the next nitration.

The mixed acid attached to the nitroanthraquinone mixture is
If desired, it can be recovered as a dilute mixed acid in a washing step, appropriately regenerated by known methods, and reused for nitration.

At this time, the total recovery rate of the mixed acid including the recovered mixed acid during the separation operation reaches 99%.

There are various methods for removing nitrite from recovered mixed acid.

In the nitration reaction, nitrous acid can be removed from the recovered mixed acid that is not diluted or slightly diluted and separated and recovered by known physical or chemical means.

Physical methods include distillation, bleaching by blowing air, or extraction.

Chemical methods include adding substances that decompose nitrous acid.

For example, hydrazine hydrate, hydrazine sulfate, sulfamino acid, sodium nitride, urea, ammonium sulfate, hydroxylamine sulfate, and the like are added and heat treated.

As a modified method for removing nitrite, there is a method in which the generated nitrite is separated or decomposed as nitration progresses.

According to this method, the content of nitrous acid is maintained at a low level throughout the nitration reaction process, making it possible to obtain 1-nitroanthraquinone at an extremely fast reaction rate and in a high yield. The recovered mixed acid obtained from nitration is preferred since no special nitrite removal treatment is required.

As the nitrous acid removal method used in this modified method, distillation or addition of hydrazine or the like is preferred.

To remove nitrous acid from diluted recovered mixed acid, either separate it into dilute sulfuric acid and dilute nitric acid, concentrate each, and separate nitrous acid from nitric acid by distillation or air bleaching, or recycle nitrous acid. This is done by oxidizing it to nitric acid.

However, it is not necessarily economically advantageous to regenerate dilute mixed acids.

Further, the removal of nitrous acid from the recovered mixed acid may be carried out by repeating the nitration reaction several times when the nitrous acid content in the recovered mixed acid exceeds a certain value, or it may be carried out for each nitration.

Alternatively, a portion may be subjected to nitrous acid removal treatment, and the remaining portion may be used for circulation without being subjected to nitrite removal treatment.

In the present invention, if the nitrous acid content in the nitrated mixed acid exceeds 1%, the nitration reaction rate decreases significantly, and in some cases, the reaction may substantially stop.

Figure 1 shows the influence of nitrous acid content on the nitration reaction rate.

Under the nitration conditions of the present invention, the rate of reduction of anthraquinone in the reaction mixture apparently follows the order-order reaction rate equation (1).

The value of the pseudo-order reaction rate constant obtained in this case is a measure of the overall nitration reaction rate.

(AQ): anthraquinone concentration in the reaction mixture: pseudo-
Curve A in FIG. 1 shows the effect on the reaction rate when only the nitrite concentration was increased under the nitration conditions of Example 2.

It is understood from FIG. 1 that the reaction rate decreases rapidly when the nitrous acid content exceeds 1%.

Furthermore, the amount of nitrous acid in the nitrated mixed acid also influences the crystallinity of the product nitroanthraquinone mixture.

When the nitrous acid content is high, fine crystals are formed, which significantly reduces the efficiency of p-filtration or separation.

Industrially, good or bad separation efficiency is a big problem, and fine crystals are extremely disadvantageous.

From the above, the nitrous acid content in the nitrated mixed acid is 1% or less, preferably 0.5% or less, particularly preferably 0.2%.
It is necessary to do the following.

The 1-nitroanthraquinone and dinitroanthraquinone obtained by the method of the present invention serve as important raw material intermediates for various dyes and pigments.

For example, the crude 1-nitroanthraquinone mixture obtained by mononitration of anthraquinone is purified by vacuum distillation and then reduced, or directly reduced to an aminoanthraquinone mixture and then vacuum distilled, or purified with nitrite. After that, reduction is performed to obtain highly pure 1-aminoanthraquinone in high yield.

The 1-aminoanthraquinone thus obtained is of the same quality as that obtained by mercury-catalyzed sulfonation of anthraquinone followed by amination, giving a dye and pigment of the same quality.

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples.

Note that parts and percentages in the text mean parts by weight and percentages by weight.

Example 1 5 parts of anthraquinone was suspended in 30 parts of 74% sulfuric acid, and 15.3 parts of nitric acid with a nitrous acid content of 0.02% and a concentration of 99% was added over 3 hours while maintaining the internal temperature of the nitration pot at 55°C.

After stirring at this temperature for 6 hours, the reaction was stopped by cooling to 30°C.

The crude 1-nitroanthraquinone mixture and the waste mixed acid are separated using a centrifuge, and after washing and drying, they are separated into 1-nitroanthraquinone mixtures with lengths of 30 to 10
5.67 parts of crude 1-nitroanthraquinone (purity 81%) in the form of columnar crystals with a diameter of 0 μm and a width of 5 to 20 cm was obtained.

The separated waste mixed acid contained 0.33% nitrous acid.

This was continuously subjected to single evaporation under conditions of 75 to 80°C and 200 to 205 mwHg.

Recovered mixed acid 4 with nitrous acid content of 0.05% and a small amount of organic matter
0.3 part was obtained from the can outlet.

The distillation rate (referred to as recovered mixed acid (A)) was 4%, and the distillate mainly consisting of nitrous acid and nitric acid was recovered as high-purity nitric acid after oxidation treatment.

Suspend 5 parts of anthraquinone in 40.3 parts of recovered mixed acid (A) and add mixed acid (23.6% sulfuric acid, 76.4% nitric acid, 0 nitrous acid).
．． 02%) was added over 3 hours while maintaining the internal temperature of the nitration pot at 55°C.

After stirring at the same temperature for 6 hours, the reaction was stopped by cooling to 30°C.

Separated from waste mixed acid using a centrifuge, crude 1 with a purity of 76% is obtained.
- 6.29 parts of nitroanthraquinone was obtained.

The crystals were columnar crystals with a length of 30 to 100 μm and a width of 5 to 20 μm.

The waste mixed acid was treated in the same manner as above to obtain 40.3 parts of recovered mixed acid whose nitrous acid content was reduced from 0.4% to 0.04%.

(Recovered mixed acid (B)) Example 2 5 parts of anthraquinone was suspended in 40.3 parts of the recovered mixed acid (B) obtained in Example 1, and mixed acid (21.7% sulfuric acid, 78% nitric acid, 78% nitric acid,
3%) was added over 3 hours while maintaining the internal temperature of the nitration pot at 55°C.

Thereafter, the reaction was carried out in the same manner as in Example 1, and the crystals had a length of 40 to 1
0011, 6.28 parts (purity 76.5%) of crude 1-nitroanthraquinone, which is a columnar crystal with a width of 5 to 20 μm, was obtained.

Example 3 Using the recovered mixed acid with a nitrous acid content of 0.05% obtained in Example 2, the reaction was repeated 17 times in the same manner as in Example 2 as the mixed acid for the next nitration.

The average yield of 1-nitroanthraquinone through 20 reactions including Example 1.2 was 76% (based on anthraquinone), and the nitrous acid content in the recovered mixed acid after nitrous acid removal treatment was 0.03 to 0. It was in the range of .5%.

Example 4 5 parts of anthraquinone was suspended in 30 parts of 74% sulfuric acid, and 15.3 parts of nitric acid with a nitrous acid content of 0.02% and a concentration of 98.5% was added over 3 hours while maintaining the internal temperature of the nitration pot at 50°C. Ta.

After stirring at the same temperature for 10 hours, the reaction was stopped by cooling to 20°C.

Separation from the waste mixed acid yielded 5.70 parts of crude 1-nitroanthraquinone (purity 81%) in the form of large columnar crystals.

A large amount of air was blown into the separated waste mixed acid at normal pressure to obtain 40.0 parts of recovered mixed acid having a nitrous acid content of 0.1%.

(Recovered mixed acid (C)) Next, recovered mixed acid (C) 40.0
5 parts of anthraquinone was suspended in 5 parts of mixed acid (sulfuric acid 23.6 parts).
%, nitric acid 76.4%) was nitrated at an internal temperature of 50%.
The mixture was added over a period of 3 hours while being kept at ℃.

After stirring at the same temperature for 10 hours, the reaction was stopped by cooling to 20°C.

Separation from the waste mixed acid yielded 6.3 parts of columnar crystals of crude 1-nitroanthraquinone (purity 77%).

The nitrous acid content in the waste mixed acid was reduced to 0.5% by the same treatment as above.
．． It was lowered to 2%.

The recovered mixed acid obtained was 40.0 parts. (Recovered mixed acid (
Example 5 Using 40.0 parts of recovered mixed acid (D) obtained in Example 4, a reaction was carried out in the same manner as in Example 4, and 6.28 parts of columnar crystal crude 1-nitroanthraquinone (purity 76) was reacted in the same manner as in Example 4. %)Obtained.

Example 6 10 parts of anthraquinone was added to 80 parts of 78% sulfuric acid, and 24.6 parts of nitric acid with a nitrous acid content of 0.02% and a concentration of 98.5% was added in 1 hour while maintaining the internal temperature of the nitration pot at 38 to 41°C. dripped.

After stirring in the same temperature range for 14 hours, the mixture was cooled to 25°C.

It was separated from the waste mixed acid using a centrifuge to obtain 11.34 parts of crude 1-nitroanthraquinone (purity 80%).

To 89.4 parts of waste mixed acid containing 0.30% nitrous acid, 2.75 parts of a 20% aqueous sulfamino acid solution was added dropwise over 30 minutes while keeping the liquid temperature at 20° C. or lower.

After 1 hour at the same temperature, no nitrogen gas was generated.

The removal rate of nitrous acid in the mixed acid at this time was 83%, and 92 parts of recovered mixed acid with a nitrous acid content of 0.06% were obtained.

10 parts of anthraquinone was suspended in 92 parts of this recovered mixed acid,
7.1 parts of 48% oleum was slowly added.

6.7 parts of nitric acid with a nitrous acid content of 0.02% and a concentration of 98.5% was added over 1 hour while maintaining the internal temperature of the nitration pot at 39 to 41°C.

After keeping the temperature in the same temperature range for 14 hours, the reaction was stopped by cooling to 25°C.

Separation from the waste mixed acid yielded 12.6 parts of crude 1-nitroanthraquinone (purity 75.5%) with good crystallinity.

The waste mixed acid was treated in the same manner as above, and the nitrous acid content was reduced from 0.4 to 0.
．． 92 parts of recovered mixed acid reduced to 0.05% was obtained.

Reference Example 1 (When nitrous acid is not removed from the recovered mixed acid) Anthraquinone nitropolymerization was carried out under the same conditions as in the second half of Example 1, except that the recovered mixed acid with a nitrite content of 0.33% obtained in Example 1 was used. .

After the additional mixed acid was added dropwise, the mixture was kept at a temperature of 55° C. for 8 hours to obtain almost the same results as in Example 1.

Although the recovered mixed acid separated from the crude 1-nitroanthraquinone contained 0.7% nitrous acid, the nitrous acid was not removed and was recycled as it was for the next nitration.

At that time, anthraquinone was nitrated under the same conditions as in Example 2, but after the completion of dropping the additional mixed acid, the temperature was 55°C and 6°C.
The desired conversion rate of 1-nitroanthraquinone was not achieved even after keeping the temperature for 12 hours, and the reaction was not completed even after keeping the temperature for 12 hours.

1 in 6.25 parts of the obtained crude 1-nitroanthraquinone
-Nitroanthraquinone content and anthraquinone content were 70% and 15%, respectively.

At this time, the nitrous acid content in the recovered mixed acid separated from the crude 1-nitroanthraquinone was 1.1%, and the reaction rate had decreased to about 174 as in Example 2.

In addition, the crude 1-nitroanthraquinone crystals obtained in Examples 1 to 3 were obtained in accordance with Example 2 in this reference example for columnar crystals with a length of 30 to 1001 t and a width of 5 to 20 μm. Crude 1-nitroanthraquinone crystals have a size of 5 to 30μ,
Most of the crystals had a width of about 3 to 5 μm, and the flow overspeed was also reduced to about 173 to 1/10 compared to Examples 1 to 3.

[Brief explanation of drawings]

Curve A shows the influence of the reaction rate when the nitrite concentration in the nitrated mixed acid was intentionally increased under the nitration conditions of Example 2.

Claims (1)

[Claims] 1. In producing nitroanthraquinone by nitrating anthraquinone in a mixed acid, part or all of the recovered mixed acid is reused as the nitrated mixed acid, and the nitrous acid content in the nitrated mixed acid is reduced. A method for producing nitroanthraquinone, characterized in that the reaction is carried out at a concentration of 1% by weight or less. 2 by reacting in a nitrated mixed acid having a composition consisting of nitric acid in an excess molar ratio with respect to anthraquinone and sulfuric acid having a concentration corresponding to 70 to 80% when the nitric acid content is excluded.
- Process according to claim 1, characterized in that nitroanthraquinone is obtained.