BE827447A - PROCESS FOR THE PREPARATION OF 1-AMINOANTHRAQUINONE - Google Patents

Description

       

   <EMI ID = 1.1>

  
 <EMI ID = 2.1>

  
The present invention relates to a novel process for the preparation of 1-aminoanthraquinone using, as

  
 <EMI ID = 3.1>

  

 <EMI ID = 4.1>
 

  
 <EMI ID = 5.1>

  
Important for pigments, dyes for tanks and anthraquinone disperse dyes so far, it has been synthesized via anthraquinone-1-sulfonic acid obtained by sulfonation of anthraquinone. However, this process of the prior art is difficult to carry out, since it requires the use of a mercury catalyst during the sulfonation step, which poses many problems with regard to the working environment and environmental pollution. As an alternative to the above process, different processes for the preparation of 1-aminoanthraquinone have been investigated, and among these processes it has been presumed that the most effective is a preparation process in which nitration and reduction reactions are used. anthraquinone. However, this process in which we use

  
to nitration and reduction of anthraquinone, involves the use of large quantities of sulfuric acid and nitric acid, which poses problems with regard to the handling of acids and the treatment of waste liquor formed. In addition, the 1-aminoanthraquinone obtained by this process contains a large amount of by-products, in particular diamine compounds and the 2-amino compound, the 1-aminoanthraquinone having essentially to be purified by complicated operations in order to

  
 <EMI ID = 6.1>

  
Therefore, this process has not been successful from an industrial point of view.

  
Several processes for the preparation of 1-nitroanthraquinone have also been proposed, processes in which 5-nitro-1,4-naphthoquinone (hereinafter referred to simply as "5-nitronaphthoquinone") is condensed with 1,3-butadiene to obtain 5-nitrotetrahydroanthraquinone, this condensation being followed by oxidation to obtain 1-nitroanthraquinone. For example, following N. NOT . Woroshtzov et al. ("Khim. Nauka i Prom", 5, 474 - 475, 1960), 1-nitroanthraquinone can be obtained by condensing 5-nitronaphthoquinone and 1, 3-butadiene in ethanol and oxidizing the product of condensation obtained with air in an alkaline alcoholic solution.

   Furthermore, in French Patent n [deg.] 1.486.803 ("Institut Premyslu Organiznco"), a process for preparing 1-nitroanthraquinone is described by reacting butadiene with 5-nitronaphthoquinone in nitrobenzene and by oxidizing the reaction product obtained by means of nitrobenzene in the presence or absence of piperidine without isolation of the reaction product. The 1-nitroanthraquinone obtained by these methods can be easily converted to 1-aminoanthraquinone by a usual reduction method.

   However, these methods have a major drawback of
-makes that, when dissolving 5-nitrotetrahydroanthraquinone obtained by condensation of 5-nitronaphthoquinone and 1,3butadiene in an appropriate solvent after isolation or without isolation, to then introduce air into the solution for the oxidation in the presence of a base such as piperidine, different by-products are also formed so that the 1-aminoanthraquinone obtained by reduction of the 1-nitronaphthoquinone formed with the different by-products is of low purity. Therefore, it is difficult to use this 1-aminoanthraquinone as an intermediate for dyes.

  
A main object of the present invention is to provide a novel process for the preparation of 1-aminoanthraquinone from the starting 5-nitrotetrahydroanthraquinone.

  
Another object of the present invention is to provide a process for preparing, from 5-nitrotetrahydroanthraquinone, high purity 1-aminoanthraquinone which can be used as such as an intermediate for dyes or other substances.

  
The above objects (1) can be achieved by catalytic hydrogenation of 5-nitrotetrahydroanthraquinone in a polar organic solvent in the presence of a hydrogenation catalyst and adding a base to the obtained reaction solution for a reaction. complementary, (2) by catalytic hydrogenation of 5-nitrotetrahydroanthraquinone in a polar organic solvent in the presence of both a hydrogenation catalyst and a base or (3) by catalytic hydrogenation of 5-nitrotetrahydroanthraquinone in a reaction medium aqueous in the presence of both a hydrogenation catalyst and a base and oxidizing the resulting excessively reduced compound in 1-aminoanthraquinone by means of air or an oxidizing agent.

   In other words, the process of the present invention comprises the following two reactions: (A) a catalytic hydrogenation reaction and (B) the reaction in the presence of a base. In the above embodiment (1), reaction (A) is completed in a reaction system, and then reaction (B) is carried out in a reaction system to which a base is added. On the other hand, in embodiments (2) and (3), reactions (A) and (B) take place in the same reaction system.

  
In either of the above embodiments (1), (2) and (3) of the present invention, there is simultaneous reduction of the nitro group of 5-nitrotetrahydroanthraquinone to an amino group, as well as the dehydrogenation of the tetrahydroanthraquinone ring, thereby forming 1-aminoanthraquinone as a reaction product. In this regard, it has been found that a characteristic reaction occurs in the reaction system, i.e., the hydrogen released from the tetrahydroanthraquinone ring under the action of the base is effectively consumed.

  
 <EMI ID = 7.1>

  
will define it in detail below. In this specification,

  
 <EMI ID = 8.1>

  
This self-oxidation and reduction reaction, which was previously unknown in the art, was found as a result of studies which resulted in the process of the present invention.

  
Note that although in either of embodiments (1), (2) and (3), 1-nitroanthraquinone can be reduced to a leuco-like compound of 1- aminoanthraquinone corresponding to the formula:

  

 <EMI ID = 9.1>


  
by means of the introduction of an excess of hydrogen, the leuco-type compound can be easily converted into 1-aminoanthraquinone by oxidation.

  
In order to more easily understand the process of the present invention, the characteristic reaction will be illustrated more particularly below on the basis of experiments carried out by the Applicant.

  
In embodiment (1), the nitro group of a 5-nitrotetrahydroanthraquinone molecule is reduced, by catalytic hydrogenation, to an amino group or its intermediate.

  
 <EMI ID = 10.1>

  
the tetrahydroanthraquinone nucleus is allowed to release hydrogen with transformation into an anthraquinone nucleus under the action of a base and, during this reaction, the group

  
 <EMI ID = 11.1>

  
into an amino group by means of the liberated hydrogen atoms.

  
If hydrogen is present in excess in the reaction system, it is presumed that 5-nitrotetrahydroanthraquinone is converted to a leuco-like compound of 1-aminoanthraquinone or

  
 <EMI ID = 12.1>

  
allows one mole of 5-nitrotetrahydroanthraquinone to absorb 3 moles of hydrogen, one can obtain, as product, 5-aminotetrahydroanthraquinone. This product can be converted into a 1-aminoanthraquinone by subjecting it to a complemen-tary reaction in the presence of a base, this reaction being followed by absorption of one mole of oxygen (see Example 2 below). Furthermore, if the absorption of hydrogen is allowed in a proportion

  
of 2 moles, as a hydrogenation product, 5hydroxylaminotetrahydroanthraquinone is obtained which, when treated

  
in the presence of a base, changes to a leuco-like compound of 1-aminoanthraquinone as a result of intramolecular or intermolecular hydrogen transposition. The leuco-like compound is easily converted to 1-aminoanthraquinone

  
by absorption of a proportion of 0.5 moles of oxygen (see Example 1 below). Further, with absorption of hydrogen in a proportion of one mole, an intermediate product is obtained which is believed to be 5-nitrosotetrahydroanthraquinone. The intermediate product is converted into 1-aminoanthraquinone under the action of a base.

  
From the above it is evident that the product

  
 <EMI ID = 13.1>

  
hydroanthraquinone is subjected to intramolecular or intermolecular hydrogen transposition or to a self-oxidation and reduction reaction under the action of a base to form 1-aminoanthraquinone or its leuco compound.

In embodiment (2), it is assumed that,

  
-treat 5-nitrotetrahydroanthraquinone with a base, intramolecular or intermolecular hydrogen transposition occurs so that the tetrahydroanthraquinone ring is dehydrogenated and the nitre group is reduced to form 1-hydroxylaminoanthraquinone which then undergoes catalytic hydrogenation to form 1-aminoanthraquinone (see Example 10 below).

   This auto-oxidation and reduction reaction is considered to proceed at a very high rate because the addition of a strong base to a solution of 5-nitrotetrahydroanthraquinone at room temperature immediately results in <EMI ID = 14.1 > Although there is no doubt that the above reaction is a main reaction, it is possible that other reactions will take place depending on the reaction conditions, notably a reaction in which a product of the partial reduction of the group 5-nitrotetrahydroanthraquinone nitro undergoes auto-oxidation and reduction by means of a base.

  
In the embodiment (2), it is certain that

  
the auto-oxidation and reduction reaction of 5-nitrotetrahydroanthraquinone contributes to the formation of 1-aminoanthraquinone. This principle is supported by the fact that when introducing from the outside into the reaction system about 1 mole

  
 <EMI ID = 15.1>

  
obtains 1-aminoanthraquinone in a practically quantitative manner (see Example 19 below). Generally, theoretically, reduction of a nitro group to an amino group requires 6 hydrogen atoms. However, in the reaction of embodiment (2), only 2 fresh hydrogen atoms are needed for the reaction, so it is taken for granted that the remaining 4 hydrogen atoms are supplied from a tetrahydroanthraquinone nucleus of the starting material. In practice, hydrogen uptake does not stop at 1 mole per mole of the starting 5-nitrotetrahydroanthraquinone, while 2 or more moles of hydrogen are absorbed, especially under vigorous reaction conditions.

  
The absorption of 2 moles of hydrogen per mole of 5-nitrotetrahydroanthraquinone gives rise to the formation of a leuco-like compound of 1-aminoanthraquinone, this compound being readily oxidized with air to 1-aminoanthraquinone. When, in the reaction of embodiment (2), more than 2 moles of hydrogen are absorbed per mole of 5-nitrotetrahydroanthraquinone, excessively reduced materials of unknown structures

  
are formed secondarily and are not necessarily converted back to 1-aminoanthraquinone by oxidation.

  
 <EMI ID = 16.1>

  
 <EMI ID = 17.1>

  
 <EMI ID = 18.1>

  
 <EMI ID = 19.1>

  
 <EMI ID = 20.1>

  
by an alkyl group and the like, a glycol such as ethylene-

  
 <EMI ID = 21.1>

  
methoxybutanol and the like, an aromatic compound such as benzene, .l. toluene, chlorobenzene, dichlorobenzene,

  
 <EMI ID = 22.1>

  
dimethylacetamide and the like, as well as other compounds

  
 <EMI ID = 23.1> from Friedel-Crafts, for example, aluminum chloride.

  
 <EMI ID = 24.1>

  
manner described above can be used in the reaction of one of embodiments (1), (2) and (3) after its isolation from the reaction system or it can be used in the reaction of embodiments (1 ) and (2) without isolation, in the form of the reaction solution obtained after the reaction of

  
 <EMI ID = 25.1>

  
Catalytic hydrogenation and subsequent treatment of 5-nitrotetrahydroanthraquinone with a base, i.e. Embodiment (1) is carried out according to the present invention as follows:

  
 <EMI ID = 26.1>

  
suspend in a polar organic solvent and charge hydrogen gas into the solution or suspension in the presence of a hydrogenation catalyst. The polar organic solvent used in this case should be inert to the hydrogenation reaction. Among the polar organic solvents satisfying this condition are, for example, alcohols such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol and the like, cyclohexanols such as cyclohexanol , cyclohexanols substituted with an alkyl group and the like, glycols such as ethylene glycol, propylene-

  
 <EMI ID = 27.1>
- diethyl) ,. diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, methoxybutanol and the like, amides such as dimethylformamide, dimethylacetamide and the like, as well as other compounds such as ethyl acetate , butyl acetate, dioxane and the like. These polar organic solvents can be used singly or in combination and are used in an amount of 5 to 100 parts by weight, preferably 10 to 50 parts by weight per part by weight of 5-nitrotetrahydroanthraquinone.

  
The hydrogenation catalysts of the present invention are those generally used for the catalytic reduction of a nitro compound to an amino compound and which contain, as an effective component, for example, palladium, platinum, ruthenium, rhodium, nickel, cobalt, copper and / or analogous metals, or a copper / chromium catalyst. In particular, a catalyst of a noble metal deposited on a support such as carbon, alumina, diatomaceous earth or the like, or else a Raney nickel catalyst is suitable.

  
 <EMI ID = 28.1>

  
catalyst (generally between about 0.002 and 20 parts by weight per 100 parts of the 5-nitro compound) varies within wide limits depending on the type of catalyst, its activity, concentration.

  
 <EMI ID = 29.1>

  
and the like. When the reaction is carried out using a supported noble metal catalyst, it is preferable to use 0.002-0.5 parts by weight of the catalyst.
(calculated on the noble metal) while, with a catalyst of a noble metal without using a support such as palladium black,

  
the amount is preferably between 0.01 and 5 parts by weight of catalyst; with a nickel, cobalt, copper or copper / chromium catalyst, the amount is preferably between 0.05 and 20 parts by weight (expressed as metal) of each of them per 100 parts of 5 -nitrotetrahydroanthraquinone.

  
The reaction temperature can be in a wide range between 0 and 160 [deg.] C, since the catalytic hydrogenation reaction involves little or no side reactions which have a detrimental influence on the main reaction. However, the reaction temperature is preferably between 10 and 120 [deg.] C in order to facilitate the reaction operations. The reaction can be carried out under normal atmospheric pressure or, if necessary, under an elevated pressure up to about 100 kg / cm 2.

  
In the catalytic hydrogenation reaction under the above reaction conditions, the absorption of 1 to 3 moles, preferably 1.5 to 2.5 moles of hydrogen in 1 mole of 5-nitrotetrahydroanthraquinone is allowed. .

  
As already indicated above, the theoretical quantity of hydrogen which must be absorbed in order to obtain 1-aminoanthraquinone quantitatively is 1 mole per mole.

  
of 5-nitrotetrahydroanthraquinone. However, if hydrogen uptake is stopped at 1 mole per mole of 5-nitrotetrahydroanthraquinone, a slight amount of an intermediate remains in the reaction system, so that 1-aminoanthraquinone is less pure. Accordingly, for the absorption in the process of this embodiment of the present invention, between 1 and 3 moles of hydrogen are used per mole of 5-nitrotetrahydroanthraquinone. However, the absorption of more than 3 moles of hydrogen per mole of 5-nitrotetrahydroanthraquinone does not appreciably alter the result. The time required for hydrogen uptake is usually between 0.5 and

  
20 hours.

  
At the end of the catalytic hydrogenation reaction,

  
a base is added to the reaction solution for the auto-oxidation and reduction reaction. In this regard, the hydrogenation catalyst can be removed by filtration before the addition.

  
 <EMI ID = 30.1>

  
the base. Although, according to the present invention, all the usual bases can be used, the following bases are nevertheless particularly preferred: oxides, hydroxides, carbonates, bicarbonates, phosphates and acetates of alkali and alkaline earth metals such as potassium, sodium, calcium, barium, magnesium and the like, as well as ammonia and organic amines such as diethylamine, &#65533; triethylamine, morpholine, piperidine, piperazine, ethanolamine, triethanolamine and the like. These bases are generally used in an amount of 0.01 to 10 moles per mole of 5-nitrotetrahydroanthraquinone. In order to suppress side reactions and to carry out the reaction regularly, the amount of the base is preferably

  
 <EMI ID = 31.1>

  
quinone. The bases can be used alone or in combination. The base can be added as such to the reaction solution or, if desired, it can be added after it has been dissolved in water, alcohol or other polar organic solvent.

  
The auto-oxidation and reduction reaction using a base can be carried out at a temperature within a wide range of 0 to 250 [deg.] C. However, from the point of view of the reaction operation, the reaction temperature is preferably between a temperature above room temperature, for example, between about
20 [deg.] C and a temperature below the boiling point of the polar organic solvent employed. Further, the reaction is generally carried out under normal atmospheric pressure, but, if necessary, it can be carried out under an elevated pressure of up to 100 kg / cm 2. The auto-oxidation and reduction reaction proceeds relatively rapidly over the temperature range described above and is generally completed after 20 hours.

   However, the reaction can be completed after 3 hours under more preferred reaction conditions.

  
When the reaction solution obtained by the catalytic hydrogenation of the starting material, followed by an auto-oxidation and reduction reaction with a base, still contains

  
the hydrogenation catalyst, this catalyst must be removed by filtration. The reaction solution obtained is cooled or concentrated as it is or after having neutralized it with an appropriate acid or else it is diluted with a product which is not a solvent for 1-aminoanthraquinone in order to separate the 1-aminoanthraquinone in the form of crystals, then it is diluted. filter and dry to obtain 1-aminoanthraquinone. When the hydrogen is absorbed in an amount greater than the theoretical amount during the reaction, part of the 1-aminoanthraquinone thus obtained is converted into a leuco-like compound of 1-aminoanthraquinone. Consequently, before the separation of 1-aminoanthraquinone,

  
it is better to inject air or oxygen into the

  
reaction solution or adding an agent to the solution

  
oxidant such as hydrogen peroxide at a temperature between 0 and 150 [deg.] C in order to convert the leuco-type compound into 1-aminoanthraquinone and thereby obtain a product of high purity.

  
The amount of oxidizing agent required for the oxidation can be easily calculated from the amount of hydrogen absorbed. Among other oxidizing agents which can be used are perbenzoic acid, tert-butyl peroxide, sodium peroxide, potassium dichromate and the like. When the reaction is carried out on a reduced scale, the oxidation reaction proceeds satisfactorily by simply allowing the reaction solution to stand in air for a period of time to ensure the contact with air. at the end of the autooxidation and reduction reaction with a base. In this way, high purity 1-aminoanthraquinone can be obtained.

  
When the hydrogenation is carried out in the presence of a base, i.e. in embodiment (2), the reaction is carried out in a polar organic solvent in the presence of both a catalyst of hydrogenation and a base, while charging hydrogen into the reaction system. This reaction does not involve any concurrent side reaction. important, so that it is not necessary to limit the reaction temperature to avoid side reactions. As a general rule, the reaction temperature can be in a wide range between 0 and 160 [deg.] C and, to facilitate the reaction operation, it is preferably in the range between 10 and 120 [deg.] C. deg.] C.

   The reaction can be carried out under normal atmospheric pressure but, if necessary or desired, it can also be carried out under an elevated pressure of up to
100 kg / cm2.

  
The polar organic solvent, the hydrogenation catalyst and the base which are used according to the invention, as well as their amounts are in each case the same as for embodiment (1). In this embodiment, it is possible,

  
 <EMI ID = 32.1>

  
moles (preferably 1.1 to 2.2 moles) of hydrogen, then the catalyst is separated by filtration. Although the time required to absorb a predetermined amount of hydrogen varies depending on the reaction conditions, including the temperature of the reaction, the amount of the hydrogenation catalyst, the concentration of 5-nitrotetrahydroanthraquinone and the like, this time is generally within the interval between 0.5 and 20 hours and, under more preferred reaction conditions, it may be in the interval between 1 and 6 hours.

  
In the reaction according to this embodiment, four hydrogen atoms of the tetrahydro ring of 5-nitrotetrahydroanthraquinone are also likely to contribute to the reduction of the nitro group. The quantity of hydrogen required to obtain 1-aminoanthraquinone stoichiometrically is

  
1 mole per mole of the starting material. Indeed, as will be demonstrated in Example 19, although the absorption of about 1 mole of hydrogen gives rise to the almost quantitative formation of 1-aminoanthraquinone, a small amount of an intermediate product, in particular, 1-hydroxylaminoanthraquinone tends to remain in the reaction system always under these conditions. As a result, a high purity product can be more easily obtained by allowing the starting material to absorb 1.1 to

  
2.2 moles of hydrogen to reduce some or substantially all of this material to leuco-1-aminoanthraquinone. In this case, at the end of the hydrogenation, to the reaction solution, air or oxygen or the same oxidizing agent is added.

  
than in embodiment (1), at a temperature of 0 to 150 [deg.] C. The catalyst can be separated by filtration or can be allowed to stand to convert the leuco compound to 1-aminoanthraquinone. However, in the case of a small scale reaction in which only a small amount of the reaction solution is worked up, the oxidation reaction proceeds satisfactorily by allowing the reaction solution to stand in air in the air. end of the hydrogenation reaction.

  
As indicated above, in the case of an absorption of more than 2 moles of hydrogen per mole of the starting 5-nitrotetrahydroanthraquinone, during the reaction of this embodiment, it also forms secondarily excessively reduced material which cannot be recycled or completely converted to 1-aminoanthraquinone by oxidation.

  
However, an appropriate choice of reaction conditions = Islands (especially the type of solvent, base and catalyst, reaction temperature and the like) makes it possible to stop

  
 <EMI ID = 33.1>

  
departure. In particular, when more than 0.5 moles of an alkali hydroxide are added per mole of the starting 5-nitrotetrahydroanthraquinone. it was found that hydrogen was not absorbed in an amount greater than 2 moles and that excessively reduced byproducts did not form as a result of further hydrogenation of leuco-1-aminoanthraquinone. This is a predominant feature of the present invention.

  
At the end of the reaction, with or without neutralization with an acid, the reaction solution from which the catalyst has been removed by filtration is subjected to cooling, condensation or dilution for crystallization. The crystals obtained are separated by filtration and dried to

  
 <EMI ID = 34.1>

  
In Embodiment (3) of the present invention, the hydrogenation reaction is carried out in an aqueous reaction medium in the presence of both a hydrogenation catalyst and a base while charging hydrogen into it. the reaction system.

  
The aqueous reaction medium can be water as it is or a mixed solution of water and an organic solvent miscible with water. Among these organic solvents, there are, for example,

  
alcohols such as methanol, ethanol, propanol, ethylene-

  
 <EMI ID = 35.1>

  
such as dioxane, 1,2-dimethoxyethane, 1,2-diethoxyethane and the like, as well as alcohol ethers such as diethylene glycol, dipropylene glycol and the like. Even when these organic solvents are not used mixed with water

  
 <EMI ID = 36.1> of Embodiment (3) of the present invention can be fully achieved. When used, the organic solvent can be mixed with water in an amount up to

  
 <EMI ID = 37.1>

  
The amount by weight of the aqueous reaction medium is generally 5 to 100 times, preferably 10 to 50 times greater than that of the starting 5-nitrotetrahydroanthraquinone. With an amount by weight less than. 5 times, the reaction sometimes proceeds incompletely, since it is difficult to stir the 5-nitrotetrahydroanthraquinone in a satisfactory manner in suspension due to the small amount of the reaction medium.

  
The catalyst; hydrogenation used in this case,

  
 <EMI ID = 38.1>

  
achievement (l). The base used in this case is also the same as in Embodiment (1), while the amount of the base used in the present embodiment is generally more than 1 mole, preferably 1 to 20 moles. per mole of 5-nitrotetrahydroanthraquinone.

  
The hydrogenation of the embodiment (3) of the present invention can be carried out under normal atmospheric pressure or under elevated pressure. In other words,

  
the present embodiment can be implemented by

  
a process under atmospheric pressure in which one places

  
5-nitrotetrahydroanthraquinone, the aqueous reaction medium, the base and the catalyst in a reactor equipped with a stirrer and. with a hydrogen inlet for the hydrogenation reaction, a reactor in which hydrogen is charged while at the same time stirring the reaction mixture at a predetermined temperature. The present embodiment can also be carried out by a high pressure process in which the materials

  
the aforementioned starting points are placed in an autoclave into which hydrogen under pressure is charged with stirring. The hydrogen can be charged into the autoclave at a pressure of between 0.5 and 100 kg / cm2 and the reaction can be carried out at a pressure of up to 100 kg / cm2.

  
The reaction temperature can be in a

  
 <EMI ID = 39.1>

  
generation according to the present embodiment, there are few or virtually no side reactions. In order to facilitate

  
reaction, the temperature is preferably between 10

  
and 120 [deg.] C.

  
In order to facilitate the reaction of the present embodiment, a surfactant which has no adverse influence on the hydrogenation reaction can be used. For example, for this purpose, a nonionic surfactant such as an alkyl ether of polyoxyethylene, an alkylaryl ether of polyoxyethylene, an alkyl ester of polyoxyethylene or a monoalkyl ester of polyoxyethylene sorbitan, or else an agent is effectively used. anionic active agent of the alkylaryl sulphonate type and the amount of this surfactant is generally between 0.001 and 1 part by weight, preferably between 0.005 and 0.5 part by weight per part by weight of 5-nitrotetrahydro-

  
 <EMI ID = 40.1>

  
reaction exerts a favorable influence on the latter, that is to say that the physical properties at the interface existing between the reaction medium and the suspended matter change so that the reaction proceeds easily even at a high concentration of &#65533; slurry, while the agitation of the reaction mixture is facilitated and the reaction rate is increased to a certain degree.

  
The hydrogenation reaction of the present embodiment is carried out under the above reaction conditions, thereby resulting in the absorption of 1, 1 to 2, 2 moles of hydrogen in 1 month of 5-nitrotetrahydroanthraquinone.

  
At the end of the hydrogenation, the solution obtained is subjected to oxidation. The oxidizing agent used in this case,

  
its amount and the oxidation temperature are the same as in Embodiment (1).

  
Upon completion of the reaction of the present embodiment, 1-aminoanthraquinone is suspended in the reaction medium together with the catalyst. Consequently, the 1-aminoanthraquinone and the catalyst can be separated from the reaction medium by filtration. To the cake obtained, a solvent capable of dissolving 1-aminoanthraquinone alone is added in order to separate the catalyst and obtain a solution of 1-aminoanthraquinone.

   Among the solvents suitable for this purpose, there is, for example, an aliphatic glycol such as ethylene glycol, propylene glycol, diethylene glycol or the like, an alicyclic alcohol such as cyclohexanol, methylcyclohexanol or analogues, a carboxylic acid amide such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone or the like, an ether such as dioxane, tetrahydrofuran, methoxybenzene: or the like , an alkylbenzene such as toluene, xylene or the like, a halogenated benzene such as chlorobenzene, dichlorobenzene or the like, an ether-alcohol such as

  
 <EMI ID = 41.1>

  
sulfuric. The solution of the reaction product from which the catalyst has been removed is cooled, or diluted with a non-solvent for 1-aminoanthraquinone, for example, water, or subjected to concentration in order to effectively obtain the solution. 1-aminoanthraquinone.

  
When carrying out the hydrogenation reaction of the present embodiment using, as the base, an alkali metal or an alkaline earth metal hydroxide, especially sodium hydroxide or potassium hydroxide , in an amount of 2 / n moles (n denoting the valence of the base metal) per mole of 5-nitrotetrahydroanthraquinone, the product is obtained as an alkali metal salt or an alkaline earth metal salt of the compound hydroquinone type of 1-aminoanthra-

  
 <EMI ID = 42.1>

  
that the catalyst can be separated by filtration without using the above organic solvent. In this case, high purity 1-aminoanthraquinone can be effectively obtained by oxidizing the catalyst-free solution with air or an oxidizing agent such as hydrogen peroxide at a temperature.

  
 <EMI ID = 43.1>

  
anthraquinone thus obtained contains practically no side products and therefore can be used as such as an intermediate for a dye or pigment.

  
As indicated above, the present invention provides a novel process for preparing 1-aminoanthraquinone from 5-nitrotetrahydroanthraquinone by catalytic hydrogenation, as well as by an auto-oxidation and reduction reaction with a base in a polar organic solvent or in an aqueous medium.

  
In this process, it is evident that the autooxidation and reduction reaction of 5-nitrotetrahydroanthraquinone

  
by means of a base plays an important role in the preparation of 1-aminoanthraquinone.

  
A predominant advantage of the present invention lies in the fact that, compared to known processes for the preparation of 1-aminoanthraquinone in which the anthraquinone is first subjected to nitration, then to reduction, while then oxidizes 5-nitrotetrahydroanthraquinone to form 1-nitroanthraquinone followed by reduction to obtain 1-aminoanthraquinone, the process of the present invention has a small number of simple steps and results in the formation of more pure 1-aminoanthraquinone with a

  
 <EMI ID = 44.1>

  
obtained can be used with or without purification as an intermediate for dyes.

  
Another advantage of the present invention is that the hydrogen atoms of the starting 5-nitro compound are effectively used for the reduction of the nitro group, since the process of the present invention is mainly based on the reaction of 'auto-oxidation and reduction. In addition,

  
 <EMI ID = 45.1>

  
The present invention starting with the condensation of 5-nitro1, 4-naphthoquinone and 1,3-butadiene according to Diels-Alder can be carried out in the same solvent. Therefore, the present invention has a very great industrial advantage compared to. known processes for the preparation of 1-aminoanthraquinone.

  
The present invention will be illustrated more particularly, without any limiting nature, in the following examples in which, unless otherwise indicated, all parts are

  
parts by weight.

Example 1

  
2.6 g of a palladium-on-charcoal catalyst are added

  
at 5% to a mixture of 260 g of 5-nitrotetrahydroanthraquinone and

  
24,000 g of ethanol, a mixture into which hydrogen is injected for absorption into the 5-nitro compound in an amount of 2 moles per mole of this compound at normal (room) temperature -and- under pressure normal atmospheric. The solution which is initially pale yellow in color takes on a reddish brown color as the reaction proceeds and a small amount of a precipitate appears in the solution. When the hydrogenation is continued, the solution

  
becomes almost transparent and turns a dark reddish-brown color upon completion of the reaction. The hydrogen contained in the reactor is replaced by nitrogen to which 400 g of a 20% sodium hydroxide solution is added, the color of the solution obtained becoming dark yellowish-brown immediately after the addition of the alkali, addition in which a small amount of bright crystals precipitate. The reaction is completed immediately, the dark yellowish-brown color being that of leuco-1aminoanthraquinone which is obtained by catalytic hydrogenation of 1-aminoanthraquinone or by absorption of one mole of hydrogen in one mole of 1-aminoanthraquinone in the same. reaction conditions; then air is charged to the solution for oxidation. During the determination, we see that there has been

  
 <EMI ID = 46.1>

  
As a result, the reaction solution turns reddish orange with the formation of a reddish orange colored precipitate.

  
 <EMI ID = 47.1> the cake with acetone in order to separate the catalyst. The filtrate formed was dried to obtain 220 g of 1-aminoanthraquinone with a purity of 98%.

  
The above process is repeated with the exception that the catalyst is separated by filtration before the addition of sodium hydroxide. The filtrate formed is dried to obtain a solid substance which is then subjected to analyzes using the infrared absorption spectrum, the nuclear magnetic resonance spectrum using CDCl3 as a solvent, as well as the mass spectrum; these analyzes reveal

  
 <EMI ID = 48.1>

  
anthraquinone.

  
The analytical results are as follows:
Infrared ray absorption spectrum: 3400, 3300, 1670,

  
 <EMI ID = 49.1>

  
Nuclear magnetic resonance spectrum value: 7.7, 6.7, 4.3, 3.5 and 2.1-2.7 parts per million.

  
Mass spectrum, m / e: 257, 243, 227 and 225.

Example 2

  
0.13 g of a 5% palladium-on-charcoal catalyst is added to a mixture of 13 g of 5-nitrotetrahydroanthraquinone and 1,200 g of ethanol and then, into the mixture obtained, hydrogen is charged with a view to the preparation. absorption in an amount of 3 moles per mole of the 5-nitro compound at room temperature and under atmospheric pressure. The solution is initially pale yellow in color, then gradually turns yellowish brown and finally, again pale yellow. Then, after replacing the hydrogen contained in the reactor with nitrogen, one adds

  
 <EMI ID = 50.1>

  
reaction, the color of which immediately turns to dark reddish brown passing through dark reddish purple and one observes

  
precipitation of a small amount of bright crystals. The reaction is quickly completed and air is charged to the reaction solution for oxidation. During the determination, it was found that there was an absorption of one mole of oxygen per mole of the 5-nitro compound. As a result of oxidation, the reaction solution turns reddish orange with precipitation of reddish orange crystals. The solution obtained is subjected to filtration, then the cake obtained is extracted with acetone in order to separate the catalyst. The filtrate is dried

  
 <EMI ID = 51.1>

  
by 95%.

  
The above process is repeated with the exception that before adding the sodium hydroxide to the reaction solution, the catalyst is removed by filtration and the resulting filtrate is dried to obtain a solid substance. The substance thus obtained is subjected to analyzes by the absorption spectrum of infrared rays and the mass spectrum; these analyzes reveal that this substance is 5-amino-1, 4, 4a, 9a-tetrahydroanthraquinone. The analytical results are the following:

  
Infrared ray absorption spectrum: 3420, 3300, 1690,

  
 <EMI ID = 52.1>

  
 <EMI ID = 53.1>

Example 3

  
 <EMI ID = 54.1>

  
After allowing to cool, 0.06 g of a 5% palladium-on-charcoal catalyst is added to the solution to which is charged with hydrogen while stirring at room temperature and under normal pressure for absorption of hydrogen. hydrogen in an amount of 2 moles per mole of the starting 5-nitro material. Then, the catalyst is filtered off. To the resulting filtrate, 6 g of a 20% aqueous sodium hydroxide solution is added, which is stirred at 60 [deg.] C for 1.5 hours for the reaction. At the end of the reaction, hydrochloric acid is added to the reaction solution for the purpose of neutralization, then the methyl cellosolve is removed by distillation under a reduced pressure of 0.2 kg / cm 2 in order to concentrate the solution. The solution thus concentrated is allowed to cool and crystals of 1-aminoanthraquinone are obtained.

   After separation by filtration, the crystals were washed with water and dried to obtain 5.6 g of 1-aminoanthraquinone with a purity of 98.5%.

  
The above process is repeated, with the exception that sodium hydroxide is added to the solution for the reaction after hydrogenation, and then the catalyst is filtered off. Similar results are obtained.

Example 4

  
122 g of 5-nitro-1,4naphthoquinone containing 10% of the 6-nitro compound, 1,000 g of ethanol are introduced into an autoclave.

  
 <EMI ID = 55.1>

  
 <EMI ID = 56.1>

  
cooling the reaction solution obtained to precipitate crystals which are then filtered off and dried to obtain 114 g of the condensation product of 5-nitro-1,4,4a, 9atetrahydroanthraquinone. The product thus obtained is charged in <EMI ID = 57.1> of 5% palladium on carbon, then hydrogen is charged therein with a view to hydrogenation at room temperature and under normal pressure in order to absorb the hydrogen in an amount of 2 moles per mole of the crude compound 0. Then, the catalyst is removed by filtration and 24 g of piperidine is added to the resulting filtrate. The solution formed is heated to 110 [deg.] C and injected with

  
 <EMI ID = 58.1>

  
during 2 hours . Then, the reaction solution is subjected

  
to distillation to remove the solvent until crystals begin to precipitate. The resulting solution is allowed to cool, then the crystals are separated and dried to obtain

  
90 g of 1-aminoanthraquinone containing 1% 2-aminoanthraquinone.

Example 5

  
 <EMI ID = 59.1>

  
to a mixture of 12.8 g of 5-nitrotetrahydroanthraquinone and
170 g of dipropylene glycol in an autoclave. Hydrogen is injected up to a pressure of 25 kg / cm 2 while stirring the mixture at 120 [deg.] C for the hydrogenation of the nitro compound, thus giving rise to the absorption of 2 moles of hydrogen per mole of the starting nitro compound. The reaction solution obtained is subjected to filtration at 120-130 [deg.] C in order to separate the catalyst therefrom. To the obtained filtrate, 10 g of a 20% aqueous sodium hydroxide solution was added while stirring at 130 [deg.] C for one hour, then diluted with 350 g of water to obtain crystals.

  
By filtration, the crystals thus formed were separated, washed with water and dried to obtain 9.8 g of 1-aminoanthraquinone with a purity of 96.5%.

  
The above process is repeated, with the exception that at the end of the hydrogenation, sodium hydroxide is added to the solution for the reaction, then the catalyst is removed by hot filtration and then, the solution is heated. diluted with water. Similar results are obtained.

Example 6

  
122 g of 5-nitro-1,4naphthoquinone containing 10% of the 6-nitro compound, 2,800 g of methyl-cellosolve and 48 g of 1,3-butadiene are charged into an autoclave, then reacted

  
at 90 [deg.] C for 2 hours. The reaction solution is allowed to stand for cooling, and then 1.2 g of a 5% palladium-carbon catalyst is added thereto. Then, the process of Example 4 was repeated to obtain 104 g of 1-aminoanthraquinone containing 7% 2-aminoanthraquinone.

Example 7

  
0.07 g of a palladium-carbon catalyst is added

  
at 5% to a mixture of 7.7 g of 5-nitrotetrahydroanthraquinone and

  
 <EMI ID = 60.1>

  
hydrogen is then charged under normal pressure in order to absorb it in an amount of 2 moles per mole of the starting 5-nitro compound. After removing the catalyst by filtration, 4 g of crystalline sodium carbonate was added to the reaction solution while stirring at a temperature of 100 [deg.] C for one hour. Next, hydrochloric acid is added to the reaction solution to neutralize it and then, by distillation, the butanol is separated from the solution until crystals begin to precipitate. After allowing to cool, the reaction solution is filtered and the crystals are washed with water, then dried to obtain 6 g of 1-aminoanthraquinone of 97.2% purity.

  
 <EMI ID = 61.1>

  
sodium phosphate instead of sodium carbonate, similar results are obtained.

  
Example 8

  
1.4 g of a palladium-on-charcoal catalyst is added to a mixture of 154 g of 5-nitrotetrahydroanthraquinone and

  
3..000 g- of. methyl-cellosolve-, -mixture in which we charge

  
hydrogen at room temperature and under normal pressure for hydrogenation. After absorption of hydrogen in an amount of 2 moles per mole of the 5-nitro compound, the catalyst is filtered off. To the filtrate, 60 g of triethylamine are added, then the mixture is stirred at 100 [deg.] C for 3 hours and the mixture is charged.

  
 <EMI ID = 62.1>

  
methyl cellosolve by distillation until crystals begin to precipitate. The solution is allowed to cool and

  
 <EMI ID = 63.1>

  
 <EMI ID = 64.1>

  
98% purity.

Example 9

  
 <EMI ID = 65.1>

  
and 170 g of cyclohexanol, 0.3 g of a Raney nickel catalyst is added: Then, hydrogen is charged into the mixture while stirring at 100 [deg.] C for the hydrogenation. After absorption of hydrogen in an amount of 2 moles per mole of the nitro compound, the catalyst is separated by filtration. To the filtrate

  
 <EMI ID = 66.1>

  
 <EMI ID = 67.1>

  
the reaction solution was cooled to 10 [deg.] C to precipitate crystals which were filtered off, washed with water and dried to obtain 9.2 g of 1-aminoanthraquinone d '98% purity.

Example 10

  
To a mixture of 260 g of 5-nitrotetrahydroanthraquinone and 10,000 g of methyl cellosolve, 2.6 g of a 5% palladium-on-charcoal catalyst and 300 g of a 20% aqueous solution of hydroxide are added. sodium, then stirred at room temperature for one hour. The solution is green in color, which is the color inherent in 1-hydroxylaminoanthraquinone. A sample of the reaction solution is taken and subjected to

  
to thin layer chromatography which reveals that virtually all of the starting 5-nitro compound is converted to 1-hydroxylaminoanthraquinone. Then, hydrogen is charged to the reaction solution for hydrogenation and the absorption of 2 moles of hydrogen in 1 mole of the 5-nitro compound is observed. The hydrogen contained in the reactor is replaced by nitrogen,

  
then air is introduced into the reaction solution for the purpose of oxidation. Upon determination, it was found that oxygen was absorbed in an amount of 0.5 moles per mole of the 5-nitro compound. The reaction solution turns reddish orange

  
with formation of a reddish orange precipitate. This precipitate is separated by filtration, washed with water and

  
dries it to obtain 220 g of 1-aminoanthraquinone having a

  
 <EMI ID = 68.1>

Example 11

  
2.6 g of a palladium-on-charcoal catalyst and 300 g of a 20% aqueous sodium hydroxide solution are added to a mixture of 260 g of 5-nitrotetrahydroanthraquinone and
10,100 g of methyl cellosolve. The solution obtained is green in color. - Immediately after the addition of the sodium hydroxide solution, hydrogen is charged therein for absorption of the latter in an amount of 2 moles per mole of the 5-nitro compound. The reaction solution is reddish orange in color when hydrogen is absorbed in a proportion of one mole with precipitation of a large amount of needle crystals but, when hydrogen is absorbed

  
in a proportion of 2 moles, the solution turns into a dark brown suspension, the color of which is almost the same as that obtained by the absorption of one mole of hydrogen in

  
1-aminoanthraquinone under the same reaction conditions. Then, the process of Example 10 is repeated to obtain results similar to those of this Example.

Example 12

  
6.1 g of 5-nitronaphthoquinone, 140 g of methyl-cellosolve and 2.4 g of 1,3-butadiene are introduced into an autoclave,

  
 <EMI ID = 69.1>

  
After allowing the reaction solution to cool, 0.06 g of a 5% palladium-carbon catalyst and 6 g of a 20% aqueous solution of sodium hydroxide are added thereto, followed by charging hydrogen to the solution. this solution at room temperature and under

  
 <EMI ID = 70.1>

  
in 5-nitronaphthoquinone in an amount of 2 moles per mole of the nitro compound. Then, the catalyst is removed by filtration and, to the filtrate obtained, hydrochloric acid is added with a view to

  
neutralization. From the solution thus neutralized, the methyl cellosolve is removed by distillation for concentration, and then allowed to cool to precipitate crystals. The crystals were filtered off, washed with water and dried to obtain 5.8 g of 1-aminoanthraquinone of 98.7% purity.

Example 13

  
In an autoclave, 122 g of 5-nitronaphtho-

  
 <EMI ID = 71.1>

  
48 g of 1. 3.-butadiene, then reacted at 80 [deg.] C for 2.5 hours. After allowing the solution to cool to precipitate

  
crystals, they are separated by filtration, they are washed

  
with water and dried to obtain 114g of 5-nitro-1,4,4a, 9atetrahydroanthraquinone. The nitro compound thus obtained is introduced into 2,800 g of methyl cellosolve, then 1.2 g of a 5% palladium-on-charcoal catalyst and 120 g of a 20% aqueous sodium hydroxide solution are added; then hydrogen is charged therein for hydrogenation, while stirring at room temperature and under normal pressure, in order to absorb this hydrogen in an amount of 2 moles per mole of the compound

  
5-nitro crude. Then the catalyst is separated by filtration.

  
and air is injected into the filtrate obtained for the purpose of oxidation

  
at room temperature for 3 hours. Then, by distillation, the methyl cellosolve is separated from the reaction solution until crystals precipitate, and then it is allowed to cool. By filtration, the crystals thus precipitated are separated, washed with water and dried to obtain 92 g of 1-aminoanthraquinone containing 1% of 2-aminoanthraquinone.

Example 14

  
 <EMI ID = 72.1>

  
quinone containing 10% of the compound 6-nitrc, 2,800 g of methylcellosolve and 48 g of 1, 3-butadiene, then reacted at 90 [deg.] C for 2 hours. After allowing to cool, to the reaction solution are added 1.2 g of a 5% palladium-carbon catalyst and 120 g of a 20% aqueous sodium hydroxide solution. Then, the process of Example 13 is repeated and one obtains

  
108 g of 1-aminoanthraquinone containing 7% 2-aminoanthraquinone.

Example 15

  
 <EMI ID = 73.1>

  
at 5% and 8 g of crystalline sodium carbonate to a mixture of 7.7 g

  
 <EMI ID = 74.1>

  
the mixture obtained is heated to 70 [deg.] C and hydrogen is charged with a view to hydrogenation under normal pressure in order to absorb

  
hydrogen in the starting 5-nitro compound in an amount of 2 moles per mole of this compound. The resulting solution is heated to 100 [deg.] C and subjected to hot filtration in order to separate the catalyst therefrom and then, by distillation, the butanol is separated off in order to condense the solution. The condensed solution is allowed to cool to precipitate crystals which are then separated by filtration,

  
 <EMI ID = 75.1>

  
98.5% purity 1-aminoanthraquinone.

  
When repeating the above process using

  
11 g of tertiary sodium phosphate instead of sodium carbonate, similar results are obtained.

Example 16

  
0.1 g of a 5% palladium-on-carbon catalyst and 10 g of a 20% aqueous sodium hydroxide solution are added.

  
to a mixture of 12.8 g of 5-nitrotetrahydroanthraquinone and
170 g of dipropylene glycol in an autoclave into which hydrogen is charged for the hydrogenation of the 5-nitro compound at 120 [deg.] C with stirring until the pressure reaches 25 kg / cm2. Hydrogen is absorbed into the starting 5-nitro compound in an amount of 2 moles per mole of the 5-nitro compound. At the end of the hydrogenation, the solution obtained is subjected to filtration at

  
 <EMI ID = 76.1>

  
obtained, 350 g of water are added in order to dilute it and crystals are obtained which are filtered off, washed with water and dried to obtain 9.7 g of 1-aminoanthraquinone with a purity of 96.7%.

Example 17

  
1.4 g of a 5% palladium-on-charcoal catalyst are added

  
 <EMI ID = 77.1>

  
anthraquinone and 3,000 g of methyl cellosolve, mixture in which one. charging hydrogen at room temperature and under normal pressure in order to absorb the hydrogen into the starting 5-nitro compound in an amount of 2 moles per mole of this compound. At the end of the hydrogenation, the catalyst is separated by filtration and air is charged into the filtrate obtained at the temperature nor- <EMI ID = 78.1>. &#65533;. &#65533; "

  
When this process is repeated using 60 g of

  
 <EMI ID = 79.1>

  
 <EMI ID = 80.1>

  
 <EMI ID = 81.1>

  
3 g of a Raney nickel catalyst are added and

  
 <EMI ID = 82.1>

  
 <EMI ID = 83.1> starting 5-nitro compound in an amount of 2 moles per mole of this compound. At the end of the hydrogenation, the catalyst is separated by filtration and, in the filtrate obtained, is passed

  
 <EMI ID = 84.1>

  
 <EMI ID = 85.1>

  
then by filtration, washed with water and dried to obtain 92 g of 1-aminoanthraquinone of 98.2% purity.

Example 19

  
0.026 g of a palladium-on-carbon catalyst is added

  
 <EMI ID = 86.1>

  
to a mixture of 2, 6 g of 5-nitrotetrahydroanthraquinone and
101 g of methyl-cellosolve, a mixture in which hydrogen is charged with a view to absorbing the latter at room temperature and under normal pressure in the 5-nitro compound in an amount of 1.1 moles per mole of this compound . Precipitation of a small amount of reddish brown crystals is observed.

  
The reaction solution is subjected to filtration, then washed with methyl cellosolve. The filtrate and washings are combined together, then neutralized with dilute sulfuric acid. Then, the solution obtained is concentrated under reduced pressure and crystals are obtained which are separated by filtration, washed with methanol, then with water, and which are dried to obtain 2, 5 g of L. aminoanthraquinone. The purity is 97.8% and the yield is
93.3%.

Example 20

  
In a glass reactor of the electromagnetically stirred type having an internal volume of 200 ml, is introduced

  
 <EMI ID = 87.1>

  
(0, 013 mol) of a 1% aqueous solution of sodium hydroxide

  
and 0.052 g of a 5% palladium-on-carbon catalyst. Then,

  
the atmosphere prevailing in the reactor is replaced by hydrogen; then hydrogenation is carried out while stirring at room temperature. After absorption of 0.015 mole of hydrogen, the hydrogen contained in the system is replaced by nitrogen, then by air in order to oxidize the excessively reduced compound obtained, while stirring for 30 minutes. The reaction product obtained jointly is separated :, with the catalyst

  
by filtration and dissolved in N, N-dimethylformamide

  
in order to separate the catalyst by filtration. To the filtrate obtained,

  
 <EMI ID = 88.1>

  
1-aminoanthraquinone (with a yield of 93.1%). The purity of 1-aminoanthraquinone is 98%.

Example 21

  
The process of Example 20 was repeated using sulfuric acid instead of N, N-dimethylformamide to separate the catalyst. Similar results are obtained.

Example 22

  
5-Nitrotetrahydroanthraquinone, an aqueous solution of sodium hydroxide and a palladium-on-charcoal catalyst are deposited in the same amounts as in Example 20, in a cylindrical glass reactor having an internal volume of 500 ml and provided with 'a thermometer, a stirrer, a hydrogen inlet and a reflux condenser, a reactor in which hydrogen is charged at a rate of 1 liter / minute for the purpose of hydrogenation, while stirring the reaction mixture at room temperature for 6 hours. Then, for the oxidation, air is charged to the reaction system at a rate of 1 liter / minute for 30 minutes. By filtration, the reaction product obtained containing the catalyst is separated off, then it is dissolved in

  
 <EMI ID = 89.1>

  
methyl) in order to separate the catalyst. The filtrate formed is condensed to obtain 2.1 g of 1-aminoanthraquinone (with a yield of 93.1%). The purity of 1-aminoanthraquinone is 98%.

Example 23

  
2.6 g (0.01 mol) of 5-nitrotetrahydroanthraquinone, 52 g (0.032 mol) of an aqueous solution of sodium hydroxide at 2.5% and 0.07 g of a sodium hydroxide catalyst are deposited. Raney nickel in an electromagnetically stirred type autoclave with an internal volume of 160 ml, followed by hydrogenation while stirring at room temperature under a pressure of 3 to 6 kg / cm2 gauge. The hydrogenation reaction proceeds smoothly. Six hours after the start of the reaction, the absorption of 0.02 mol of hydrogen is observed, then the absorption is stopped. Subsequently, the hydrogen contained in the reaction system is replaced by nitrogen and the reaction solution obtained is filtered in a stream of nitrogen in order to separate the catalyst therefrom.

   For the oxidation, air is passed through the filtrate formed and 2.1 g of 1-aminoanthraquinone are obtained <EMI ID = 90.1>

Example 24

  
25.7 g (0.1 mole) of crude 5-nitrotetrahydroanthraquinone obtained by condensing, in ethanol, are deposited.

  
1,3-butadiene and 5-nitronaphthoquinone containing 10%

  
6-nitronaphthoquinone, in a reactor with an internal volume of 2 liters with 514 g (0.13 moles) of a 1% aqueous solution of sodium hydroxide and 0.52 g of a palladium-carbon catalyst at 5%, then hydrogenation is carried out with hydrogen

  
at room temperature and under normal pressure while stirring. The hydrogenation reaction is stopped after the absorption of

  
0.2 mole of hydrogen. In the reaction solution formed, air is charged to oxidize the excessively reduced compound formed. By filtration, the reaction product obtained together with the catalyst is separated. The product thus separated is mixed with N, N-dimethylformamide in order to dissolve the product alone, then the catalyst is separated by filtration. The resulting filtrate is diluted with water for precipitation and 21 g of 1-aminoanthraquinone containing 2% 2-aminoanthraquinone are obtained (with a yield of 94.2%).

Example 25

  
The process of Example 20 is repeated, with the exception that instead of the 1% aqueous sodium hydroxide solution, 52 g of an aqueous solution containing 0.87 g (0.01 mol) is used. morpholine. By filtration, the reaction product formed is separated from the reaction solution together with the catalyst. Then, the product is dissolved in N, N-dimethylformamide in order to separate the catalyst by filtration, then water is added to dilute it, thereby precipitating crystals. By filtration,

  
the crystals thus precipitated are separated, washed with water and dried to obtain 2.1 g of 1-aminoanthraquinone (with a yield of 93.1%). The purity is 97%.

Example 26

  
The process of Example 25 is repeated, with the exception that the 52 g of the aqueous solution contains 1.49 g
(0.01 mole) of triethanolamine instead of morpholine. Similar results are obtained.

Example 27

  
The process of Example 25 is repeated, with the exception that the 52 g of the aqueous solution contains 0.86 g.
(0.01 mole) of piperazine instead of morpholine. Similar results are obtained.

Example 28

  
The hydrogenation reaction of Example 20 was repeated, with the exception that the 1% aqueous sodium hydroxide solution was used in an amount of 120 g (0.03 mole). The reaction is completed 3 hours after its start and the absorption of 0.02 mol of hydrogen is observed. In this example, the product obtained

  
is completely dissolved in the solution. The catalyst is separated by filtration in a stream of nitrogen. Subsequently, air is passed through the resulting filtrate for the purpose of oxidation, and 2.16 g of 1-aminoanthraquinone are obtained (with a yield of 95.7%).

  
 <EMI ID = 91.1>

Example 29

  
 <EMI ID = 92.1>

  
of an aqueous solution containing 0, 024 moles of barium hydroxide instead of the 1% aqueous sodium hydroxide solution. Similar results are obtained.

Example 30

  
The hydrogenation reaction of Example 28 was repeated with the exception that 0.5 g of a polyoxyethylene nonylphenyl ether ("Emulgen 905", manufactured by "Kao-Atlas Co.) was also added to the reactor. , Ltd "). The reaction is complete

  
2 hours after its onset; During this period, the absorption of 0.02 mol of hydrogen is observed and the product obtained is completely dissolved in the solution. The catalyst is separated by filtration in a stream of nitrogen. Then, air is passed through the filtrate obtained for the oxidation and one obtains

  
 <EMI ID = 93.1>

  
 <EMI ID = 94.1>

CLAIMS

  
1. Process for preparing 1-aminoanthraquinone, characterized in that it comprises the steps which consist in:

  
(1) subjecting 5-nitro-1,4,4a, 9a-tetrahydroanthraquinone. 4 catalytic hydrogenation in a polar organic solvent in the presence of a hydrogenation catalyst and adding a base to the reaction system during or after the reaction of 'hydrogenation, or

  
(2) subjecting 5-nitro-1,4,4a, 9a-tetrahydroanthraquinone to catalytic hydrogenation in an aqueous reaction medium in the presence of a hydrogenation catalyst and a base, and then oxidizing the obtained reaction product with air or an oxidizing agent.


    

Claims (1)

2. Method according to claim I, characterized in that it comprises the steps of submitting the <EMI ID = 95.1> catalyst in a polar organic solvent in the presence of a hydrogenation catalyst and adding a base to the reaction system during or after the hydrogenation reaction. 3. Method according to claim 2, characterized in that first of all the hydrogenation catalyst is introduced into the reaction system for the hydrogenation reaction, then the aforementioned base is introduced into the reaction system at the end of the first reaction. 4. A method according to claim 2, characterized in that simultaneously introducing the hydrogenation catalyst <EMI ID = 96.1> 5. A method according to claim 4, characterized in that the base is an alkali hydroxide which is uses in an amount greater than 0.5 mole per mole of 5-nitro-1,4,4a, 9atetrahydroanthraquinone. 6. Process according to claim 2, characterized in that the 5-nitro-1, 4, 4a, 9a-tetrahydroanthraquinone is used in the form of the reaction solution obtained by reacting <EMI ID = 97.1> polar organic solvent. 7. Process according to Claim 6, characterized in that the hydrogenation catalyst is palladium on carbon, while the polar organic solvent is chosen from the group <EMI ID = 98.1> diethyl, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether and methoxybutanol. 8. Method according to claim 2, characterized in that the polar organic solvent is chosen from the group comprising p -hydroxyethyl-methyl ether, -hydroxydiethyl ether, diethylene glycol monomethyl ether, monoethyl ether. of diethylene glycol and methoxybutanol. 9. The method of claim 2, characterized in that it comprises the step of oxidizing the reaction solution obtained with air or an oxidizing agent. 10. The method of claim 1, characterized in that it comprises the steps of subjecting 5-nitro-l, 4, 4a, 9a-tetrahydroanthraquinone to catalytic hydrogenation in an aqueous reaction medium in the presence of a catalyst. hydrogenation and a base, then oxidizing the resulting reaction product with air or an oxidizing agent. 11. The method of claim 10, characterized <EMI ID = 99.1> 12. The method of claim 10, characterized in that one carries out the hydrogenation reaction in the presence of a surfactant. 13. The method of claim 10, characterized in that it also comprises the steps of separating <EMI ID = 100.1> catalyst, dissolving the reaction product in an organic solvent and separating the catalyst from the reaction product. 14. The method of claim 10, characterized in that the reaction is continued until the absorption of 1, 1 to 2, 2 moles of hydrogen in one mole of 5-nitro-l, 4,4a, 9a -tetrahydroanthraquinone, 15. The method of claim 10, characterized in that the base is the hydroxide of an alkali metal or of an alkaline earth metal, this hydroxide being used in an amount of 2 / n moles per mole of 5-nitro-1,4,4a, 9a-tetrahydroanthraquinone, n representing the valence of the base metal. 16. The method of claim 15, characterized in that it also comprises the step of removing the hydrogenation catalyst from the reaction solution before oxidizing the resulting filtrate with air or an oxidizing agent. 17. The method of claim 16, characterized in that the hydrogenation catalyst is palladium on carbon, while the oxidation reaction is carried out with air. 18. The method of claim 10, characterized <EMI ID = 101.1> mole of 5-nitro-1, 4, 4a, 9a-tetrahydroanthraquinone. Approved the addition of a word.