KR810001030B1 - Process for the preparation of aromatic anino azo compound from aromatic amines via diazotosation by nitrous vapours,coupling,and rearrangement reactions - Google Patents

Abstract

Aromatic aminoazo compd. was prepd. in quant. yield and 99% purity as follows. Put aromatic amine, aromatic amine salt and water to α, β, γ respectively. The wt. ratio of reaction medium as 10<α<70, 5<γ, 13<β and α+β+γ=100 was kept, aromatic amine was diazotized with a stream of nitrous vapours to give diazonium salt. Then, this salt was transferred to aromatic amine by coupling and rearrangement was taken place to produce aromatic diazoamino compd.

Description

Process for producing aromatic aminoazo compounds from anti-aromatic amines by diazotization reaction, coupling reaction and potential reaction using nitrogen vapor

1 is a three component diagram of a reaction medium composed of aniline (α), aniline hydrochloride (β) and water (γ) in the process of the present invention.

2 is a three component diagram of another example as in FIG.

The present invention relates to a method for producing an aromatic aminoazo compound by diazotization of an aromatic amine by nitrogen vapor, coupling of a diazonium salt by an aromatic amine, and an electric potential of an aromatic diazo amino compound produced as an intermediate. The process according to the invention relates in particular to a process for the preparation of P-aminoazobenzene starting from aniline.

Methods of preparing aromatic aminoazo compounds starting from aromatic amines are described in the literature. These methods have been performed in one or more steps. Thus, according to Fierz-David (Principal peration in Dyestuff Chemistry, 8th edition, 1952, pp. 265-6), P-aminoazobenzene first diazotizes aniline at low temperatures and then couples the diazonium salt with aniline. After ringing and precipitation, diazoaminobenzene (or triazene) is separated into a solid state, and finally triazine is dissolved in aniline and aniline hydrochloride is added to convert triagen into P-aminoazobenzene. From aniline.

Attempts have been made in order to obtain aromatic aminoazo compounds by reducing the number of processes and carrying out processes under conditions in which diazonium salts and / or triazenes have been converted directly in the medium in which they were produced. Thus, East German Patent No. 77/985 suggested performing all three of these steps simultaneously by injecting hydrochloric acid into aniline, water and sodium nitrite mixtures heated to about 50 ° C. or higher, generally about 100 ° C. This method is carried out at high temperature in the presence of a relatively large amount of water. One of the many drawbacks is the low yield of P-aminoazobenzene and the relatively high production of O-aminoazobenzene.

Aminoazobenzene hydrochloride is also obtained in succession in a single process using alcohols having up to 3 carbon atoms and starting material aniline under very specific concentration conditions. This technique is described in US Pat. No. 2,538,431. However, the presence of alcohol is likely to cause secondary reactions and increases the complexity of the process. The reaction should also be permanently monitored to prevent the production and accumulation of alkyl nitrite in the medium, which is well known to be unstable.

GOODRICH's French Patent No. 1,192,374 discloses aromatics by adding nitrite at 0-50 ° C. to the reaction medium in which aniline, aniline hydrochloride and water have a ratio of 2.5 to 12 moles of aniline and 1.03 to 2.5 moles of acid per mole of nitrite used. A two step process for preparing aminoazo compounds, in particular P-aminoazobenzene, is described. Diazoaminobenzene is transposed to aminoazobenzene in the second step carried out at 40 to 75 ° C., and this dislocation reaction is preferably carried out in the presence of Lewis acid. Lewis acids catalyze this translocation reaction. According to this process, which requires two steps to be carried out at different temperatures, it is possible to obtain P-aminoazobenzene in about 90% yield and the reaction time usually takes one hour or several hours. In this process, the use of aluminum chloride is very technically complex and the conversion rate of triazenes is non-quantitative, therefore aminoazobenzenes containing small amounts of triazane are obtained at the end of the reaction, which on the one hand There is a significant drawback with respect to the purification of P-aminoazo benzene which, on the other hand, results in yield loss.

Other techniques have been developed for preparing diazonium salts or triazenes in advance to convert the triazenes into aromatic aminoazo compounds in a single process. [K.H. MEYER Berichte, 54, 2, 265 2,273 (1971), described the possibility of obtaining P-aminoazobenzene from benzenediazonium halides and aniline hydrochloride by adding a concentrated aqueous solution of acetic acid and sodium formate. However, the yield is low.

It is also known that when aniline hydrochloride and diazonium chloride are reacted in an aqueous medium containing free hydrochloric acid, P-aminoazobenzene can be obtained directly from benzenediazonium chloride and aniline. However, this is a very slow reaction which is carried out in homogeneous medium and in poor yield.

[H.V. KIDD-Journal of Organic Chemistry, 2. 198-207 (1937)].

Physicalsche Cheme, 110, 251-265(1925)는 특히 아닐린 외에 소량의 아닐린 염산염 및 때로는 소량의 물을 함유한 매질 내에서 트리아젠을 P-아미노아조벤젠으로 전화시키는 방법을 제안하였다. 물의 존재는 전위 반응률을 감소시킨다는 사실을 나타내었다.Finally, GOLDSMITH Zeitschrift

Physicalsche Cheme, 110, 251-265 (1925) proposed a method for the conversion of triagen to P-aminoazobenzene, especially in a medium containing a small amount of aniline hydrochloride in addition to aniline and sometimes a small amount of water. The presence of water has been shown to reduce the potential response rate.

A review of the chemical literature reveals that it is a potential reaction, which is a slow and incomplete reaction among all diazotization, coupling and dislocation reactions. However, by the addition of a catalyst (French Patent No. 1,192,374) or by carrying out the reaction in the presence of an extremely limited amount of aliphatic alcohol having up to three carbon atoms (described in US Patent No. 2,538,431), this potential reaction is promoted. Attempts have been made. However, these techniques make it impossible to convert aromatic diazoamino compounds into aromatic aminoazo compounds quickly and collectively in quantitative yield.

French Patent No. 2,306,977 to AMERICAN CYANAMID discloses a second fluid stream consisting of a first fluid stream of a reagent containing a large amount of aromatic amine, an excess of an inorganic acid and water close to the stoichiometric amount of the reaction, and an aqueous solution of alkali nitrite in a tubular reactor. It describes a process for producing an aromatic aminoazo compound characterized by mixing. Thus, aromatic aminoazo compounds are obtained with good yields and rapid reaction rates. It should be noted that inorganic derivatives (such as sodium chloride…) are also produced in stoichiometric proportions. The presence of inorganic derivatives generally results in heterogeneity in the medium which can reduce the conversion rate of the reaction intermediate. If necessary, these inorganic derivatives need to be separated and purified in order to suppress the contamination.

The present invention relates to a method for producing an aromatic aminoazo compound, in which an aromatic amine is diazotized by nitrogen vapor, the diazonium salt is coupled to an aromatic amine, and the diazoamino compound is transposed. According to this method, all reactions can be carried out by a single process at a rapid reaction rate without addition of a catalyst, in which all of the aromatic diazoamino compounds are converted into aromatic aminoazo compounds. More specifically, the present invention relates to a method for diagnosing aromatic amines, coupling diazonium salts to aromatic amines, and then transposing the aromatic diazoamino compounds to produce aromatic aminoazo compounds, respectively, And nitrogen vapor is introduced into the medium formed such that the weight ratio of the aromatic amine represented by γ, the salt of the aromatic amine, and water is always maintained in the following relationship.

10 <α <70

13 <β

5 <γ

α + β + γ = 100

The medium in which the reaction is carried out is generally in a single liquid phase, which is organic and consists mainly of aromatic amines, salts of these aromatic amines and water.

In addition, the reaction medium does not necessarily have to be a liquid medium and may optionally include a dispersed solid phase composed of salts of aromatic amines.

In the process of the present invention, it is described in particular for the preparation of P-aminoazobenzene starting with aniline or one of its intermediates.

Therefore, one of the objects of the present invention is that the three components of aniline, aniline hydrochloride and water mainly have a weight ratio of α, β and γ as described above in the reaction medium.

10 <α <70

13 <β

5 <

α + β + γ = 100

Nitrogen vapor is introduced into the medium, which is formulated to always conform to, diazotizing the aromatic amine, coupling the diazonium salt to the aromatic amine, and then transposing the aromatic diazoaminobenzene to P-aminoazobenzene. It relates to a method of manufacturing.

Within the defined concentration range, it was found that this potential reaction was completed at a time when the total reaction time was less than 2 hours at 50 ° C. With relatively small amounts of aniline (eg up to 45%), it is desirable to slightly increase the minimum proportion of hydrochloride. For aniline with a ratio of about 10%, it was observed that beneficial results were obtained when the ratio of aniline hydrochloride was not less than 18% throughout the reaction.

Therefore, the point M can be defined on the three component diagram by the α, β and γ coordinates. Good results are obtained if point M is located inside the region of the diagram of FIG. 1 bounded by points A, B, C, D and B throughout the reaction.

In FIG. 1, when point M is in the boundary region consisting of points A ', B', C 'and E, excellent results in terms of reaction rate and yield are obtained. The exact coordinates of each point of this diagram are shown in the following table.

It is clear that point M changes with the progress of the reaction when nitrogen vapor is introduced into the medium consisting of aniline, aniline hydrochloride and water. For convenience, this medium will later be referred to by the name of the three component mixture. The change in point M is related to the aniline, aniline hydrochloride consumed on the one hand and to the increase in the amount of water from the reaction on the one hand.

The amount of water produced in the reaction is also calculated. When the resulting point M 'is outside the above-mentioned region, the amount of water initially added is sufficiently reduced so that the point M' comes to the inner region.

Nitrogen oxides NO and / or nitrogen dioxide NO ₂ and / or nitrogen anhydride N ₂ O ₃ can be used in various proportions as the nitrogen vapor. In all cases nitrogen vapor allows the aminoazo compound to be obtained in substantially quantitative yield. On the other hand, the composition of nitrogen vapor has a sensitive effect on the reaction rate and the total consumption of nitrogen vapor.

N ₂ O ₃ or NO, N ₂ O ₂ (NO is a carrier of liquefied N ₂ O ₃ ) or NO, NO ₂ (NO is a carrier of liquefied NO ₂ and the molar ratio of NO in each mixture is 1 to 200, preferably Preferably from 2 to 100).

The NO, NO ₂ mixture is clearly obtained from O ₂ and NO.

Nitrogen vapor can be diluted with an inert gas such as nitrogen. A mixture of air and NO can easily dilute nitrogen vapors.

The amount of nitrogen vapor introduced should not be too at least because of profitability and not too much due to the risk of side reactions. As a general rule, the amount of nitrogen vapor introduced is such that a diazotizing agent can be introduced in an amount of 0.05 to 1, preferably 0.1 to 0.6 equivalents, relative to the mixture consisting of 1000 g of aniline, aniline hydrochloride and a total amount of water. This equivalent of the diazotizing agent represented by DA may vary depending on the nature of the nitrogen vapor. NO; DA, for each mole of NO ₂ and N ₂ O ₃ is 1/2; 1/2 and 2 moles. Depending on the mixture used, the DA relative to a total of 1 mole is 1/2 to 2 moles. NO, NO ₂ mixtures containing large amounts of NO are clearly large amounts for NO, N ₂ O ₃ mixtures.

If point M is located within the desired area of the diagram, a large amount of nitrogen vapor can be used. This amount is greater than 0.5 moles per 1000 g of the mixture than D.A. and there is no risk of a secondary reaction. This fact is of great importance from an industrial standpoint as it results in high productivity for a given reactor.

The molar ratio of aniline / D.A. And aniline hydrochloride / D.A. Is preferably fixed within the ranges shown below.

At the end of the reaction, the resulting p-aminoazobenzene can be separated from the reaction medium by known methods as described in French Patent No. 1,192,374 and US Patent No. 2,538,431. The p-aminoazobenzene can be separated in the free state or in the form of hydrochloride by distillation or precipitation to recrystallize. After adding water to the reaction medium, an organic layer composed of aniline and p-aminoazobenzene can also be separated. The organic layer can be distilled to remove aniline and the aminoazobenzene can be recrystallized from a solvent such as petroleum ether.

The reaction mixture can also be extracted with aliphatic hydrocarbons or aromatic hydrocarbons such as benzene and toluene, whereby it is possible to selectively separate p-aminoazobenzene. This type of extraction method is clearly novel and forms another subject of the invention in particular by means of means attempted to carry out the method of the invention.

Therefore, the present invention is directed to a method for extracting p-aminoazobenzene in a medium consisting of aniline, aniline hydrochloride and water, and in a medium of α, β and γ weight ratios according to the above rules, which extraction method is p-aminoazobenzene And aliphatic hydrocarbons or aromatic hydrocarbons such as benzene and toluene. As a general rule, the amount of aromatic hydrocarbon used causes the weight ratio of hydrocarbon to 0.3 to 5, preferably 0.5 to 1, to the amount of medium in which p-aminoazobenzene is present. After extraction, the extract is distilled off to separate the solvent and distill the incorporated aniline. The amount of aniline incorporation depends on the various composition ratios of the medium in which p-aminoazobenzene is present.

The aforementioned method can be carried out using aromatic amines in addition to aniline. Oro-, meta-, and para-toluidines, naphthylamines, halogen-containing anilines, and alkylanilines having two alkyl groups having 1 to 4 carbon atoms without being fixed to nitrogen atoms can be used. It has been found that a quick and complete conversion response can be obtained by meeting the following rules relating to the weight ratios of α, β and γ.

10 <α <70 5 <γ

13 <β α + β + γ = 100

However, replacing the amines with other aromatic amines may optionally reshape the aforementioned boundaries slightly. As a general rule, good results are obtained with a molar ratio of amine / amine hydrochloride of 0.25-8, preferably 0.25-5, and amine / D.A. And the molar ratio of amine salt / D.A. Is obtained within the aforementioned range according to the process carried out using aniline and aniline hydrochloride as starting materials.

For convenience reasons, the aromatic amine salts that can be used in the process of the invention are usually hydrochloride salts. However, in addition to hydrochlorides, bromates, sulfates (which must be used to prevent sulfonation reactions), aromatic amine salts such as phosphates and nitrates, or organic acid salts such as acetic acid can also be used.

Mixtures of salts of these acids can also be used if necessary.

It has been observed that a rapid and total conversion can be obtained by meeting the rules for the total amount ratios α, β and γ described above.

However, replacing hydrochloric acid with another acid may arbitrarily recalibrate the aforementioned boundaries. If nitric acid is used instead of hydrochloric acid, a preferred region is determined, where point M must be located within this region for good results in terms of reaction rate and yield. This area is bounded by points A ' ₁ , B' ₁ , C ' ₁ and D' ₁ in the diagram of FIG. The exact coordinates of each point in this diagram are shown in the following table.

Moreover, good results for a given aromatic amine and aromatic amine salt are generally given by amine / amine salts, amine / D.A. And the ratio of amine salt / D.A. Is obtained when selected within the range defined according to the method carried out using aromatic amine (such as aniline) and aromatic amine hydrochloride as starting materials.

The method for producing an aromatic aminoazo compound according to the present invention is generally carried out at a temperature of 25 to 100 ℃, preferably 30 to 60 ℃. Within the preferred range, the total reaction time is sufficient to be 1 hour or less.

As mentioned earlier, the medium in which the rearrangement reaction of the aromatic diazoamino compound is carried out necessarily consists of an aromatic amine, an aromatic amine salt and water. According to a variant of the invention, small amounts of other substances, such as alcohols, can optionally be added to the reaction medium composed of aromatic amines, aromatic amine salts and water, which in principle does not alter the mode in which the reaction is carried out. This corresponds to the main characteristics of the reaction. That is, the rules relating to the weight ratios α, β and γ are followed.

However, the amount of compound added optionally corresponds to almost 25% of the total amount of aromatic amine, aromatic amine salt and water. The use of compounds such as alcohols can reduce the concentration of aromatic amines while keeping the concentration of aromatic amine salts constant.

This is industrially beneficial because it reduces the recycle of aromatic amines. From an industrial point of view, the method is very important. It significantly simplifies the route from aromatic amines to aromatic aminoazo compounds, which can be prepared in a single step, with a quantitative conversion and yield also quantitative to the nitrogen vapor used. The total reaction time is greatly shortened compared to the conventional method.

According to the method of the present invention, the production of inorganic derivatives can be avoided, as opposed to the method of using alkali nitrite and thus forming with alkali salts. The method of the present invention is simpler in technical terms. The method of the present invention has little environmental pollution. This is an advantage not available in other ways.

The use of alkali nitrites in place of nitrate vapors cannot be expected.

Aromatic aminoazo compounds are of great importance from an industrial standpoint, which can be easily converted to aromatic diamines by hydrolysis reactions by conventional methods. Of these diamines, starting with aniline, all para multiamines such as p-phenylenediamine used for the production of high polyamides can be particularly exemplified.

The present invention will be described in detail by way of examples.

Example 1

While maintaining the tricomponent mixture containing 40% by weight of aniline, 30% by weight of aniline hydrochloride and 30% by weight of water at 50 ° C, 1.6 g of nitrogen dioxide NO ₂ concentrated in a trap of NO airflow held at 25 ° C was kept for 25 minutes. Introduced at a rate of 30 l / hr. NO from the reactor is continuously recycled. Once the total content of NO ₂ is introduced, the medium is held at 50 ° C. for 5 minutes. The mixture is neutralized with 2N sodium hydroxide to maintain aniline and then export to toluene. Toluene and aniline are removed by distillation of the extract and 16.1 g of a red solid identified as p-aminoazobenzene is obtained in a yield of 99%. The yield of aminoazobenzene for inverted aniline and inverted nitrogen vapor is 100%.

Example 2

The method of Example 1 was repeated as it was, but the recovery method of amino azobenzene was changed.

At the end of the reaction, the medium is extracted twice with 150 cm 3 and 100 cm 3 of toluene, respectively. Mix the toluene extract. Distillation separates toluene and aniline and frees 16 g of aminoazobenzene.

Example 3

The method of Example 1 was repeated as it was, but the recovery method of amino azobenzene was changed. The final reaction solution is steam distilled to separate aniline. The aminoazobenzene is recovered in the form of a solid dispersed in an aqueous solution of aniline hydrochloride. After filtration drying, 16.1 g of aminoazobenzene is obtained.

Example 4

According to another example, the reaction parameters are reviewed.

Composition of 3-component mixtures (aniline, aniline salts, water)

-Molar ratio of nitrogen vapor mixture

-NO feed rate

Characteristics of Nitrogen Steam

The results are shown in the table below.

TABLE 1

Claims (1)

The weight ratio of the reaction medium composed of aromatic amine, aromatic amine salt and water in the three-component reaction medium represented by α, β and γ, respectively, 10 <α> 70 5 <γ 13 <β α + β + γ = 100 The preparation of an aromatic aminoazo compound by diazotizing the aromatic amine by a nitrogen vapor and introducing a nitrogen vapor, and a diazonium salt produced by the present invention is afflicted with an aromatic amine, and then displaces the resulting aromatic diazoamino compound. Way.

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