JPS6042165B2 - Method for recovering ammonia from benzophenone imines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention enables benzophenone imine to react with water without decomposing the benzophenone azine in the benzophenone imine oxidation reaction solution (including benzophenone azine and unreacted benzophenone imine). This invention relates to a method for recovering ammonia and benzophenones from benzophenone imines.

Benzophenone imines are intermediates in the reaction of synthesizing hydrazine salts from benzophenones and ammonia (benzophenone method), and the benzophene method is as follows.

Benzophenone imines are synthesized by condensation of benzophenones and ammonia, and when benzophenone imines are further oxidized with molecular oxygen using dissolved copper as a catalyst,
Benzophenoneazines are synthesized.

When benzophenone azines react with acids, they form benzophenones and hydrazine salts, which are themselves industrially useful and are also raw materials for the synthesis of hydrazine. For example, when sulfuric acid is used as the acid, it becomes hydrazine sulfate. The above reaction will be explained using a series of reaction equations when benzophenone is used as the benzophenone.

In addition to the reaction formulas (1), (2), and (3), the process for synthesizing hydrazine salts using benzophenones as a starting material requires that the copper catalyst used in the oxidation is expensive, and that if copper is present, there are problems with subsequent operations. There may also be cases where a copper removal and recovery process is required because it may cause problems. Examples of methods for removing copper from the oxidizing solution include a method of extraction with aqueous ammonia as known in US Pat. No. 2,870,206, and a method of extraction with an acid. However, when an acid is used, unreacted imines remaining in the oxidizing solution are hydrolyzed to produce benzophenones and ammonium salts.

For example, when sulfuric acid is used as the acid, the following reaction (4) occurs. Therefore, when an acid is used for the purpose of extracting copper oil, not only copper but also ammonium salts resulting from unreacted species are extracted from the aqueous layer at the same time.

On the other hand, when copper extraction is performed with ammonia, the residual imine in the oxidizing solution is not decomposed, but since sulfuric acid is used in the next step of hydrolyzing azine, the same reaction as (4) occurs. . Even if the purpose is different, such as recovering copper or hydrolyzing azines, as long as an acid is used, imines will be hydrolyzed and ammonium salts will be produced.

Unless the ammonium salts thus produced are properly treated or disposed of, they will gradually accumulate in the aqueous layer and seriously impede the reaction and operation. In addition, considering that ammonia and acid, which correspond to imines, are consumed, it is said to be extremely disadvantageous industrially to leave a large amount of unreacted imine due to oxidation in the series of human and radin salt synthesis processes mentioned above. I have no choice but to. In order to avoid leaving benzophenone imines, it is of course necessary to increase the oxidation reaction rate in (2). is possible.

In order to obtain a high reaction rate, it is generally necessary to increase the reaction temperature, lengthen the residence time, or increase the catalyst concentration. leading to increased costs. Also, (2)
Naturally, it is thought that the number of by-products in the reaction will increase.
Considering that benzophenones are expensive drugs,
It goes without saying that suppressing by-products as much as possible is an important condition for establishing the processes (1) to (3). The oxidation reaction rate is usually 70-99%. As a result of intensive efforts to solve these problems, the present invention was completed by discovering a method of reacting unreacted benzophenone imines in the oxidation reaction solution and decomposing them into the original benzophenones and ammonia. The present invention is based on the general formula (wherein R1 and R2 are a chain type, cycloaliphatic or aromatic hydrocarbon group having 1 to 10 carbon atoms, an ether group consisting of the hydrocarbon group, an acyl group, an acyloxy group,
Mutually identical or different groups selected from the group consisting of an alkoxycarbonyl group, a disubstituted amino group, a halogen group, a hydroxy group, a nitro group, and a cyano group, or R1 and R2
may be taken together to represent a single bond or ring.

Moreover, Mln is 0 or an integer of 1 to 5. ) is oxidized with molecular oxygen in the presence of a copper catalyst to produce benzophenone azines,
Remaining unreacted benzophenone imines in this oxidizing solution,
This is a method for recovering ammonia from benzophenone imines, which is characterized by recovering ammonia by reacting it with water in the presence of a carboxylic acid.

The benzophenonimines used in the present invention are compounds represented by the following general formula.

(However, in the above formula, R1 and R2 have 1 to 10 carbon atoms.
chain formula, cycloaliphatic or aromatic hydrocarbon groups, ether groups consisting of these hydrocarbon groups, acyl groups, acyloxy groups, alkoxycarbonyl groups, disubstituted amino groups, halogen groups, hydroxy groups, nitrile groups, nitro groups, mutually the same or different groups selected from the group consisting of cyano groups, or R1 and R2 taken together may form a single bond or ring. Also M. ．． n is 0 or an integer of 1-5. ) Specific examples include benzophenonimine, 2-, 3-, or 4-methylbenzophenonimine, 2-, 3-, or 4-ethylbenzophenonimine, 2-, 3-, or 4-n-and/ or IsO-propylbenzophenonimine, 2-, 3-, or 4-n- and/or IsO- and/or tert-butylbenzophenonimine, 2-, 3-, or 4-amylbenzophenonimine, 2-, 3- or 4-decylbenzophenonimine, 2-3- or 4-methoxybenzophenonimine, 4-cyclohexylbenzophenonimine, 4
-Phenylbenzophenonimine, 2●4-dimethylbenzophenonimine, 2●3-dimethylbenzophenonimine, 3●4-dimethylbenzophenonimine, 2.
4-dimethylbenzophenonimine, 2,3-diethylbenzophenonimine, 3●4-diethylbenzophenonimine, 2-methyl-4-ethylbenzophenonimine, 2-methyl-4-butylbenzophenonimine, 2
・2″-, 3・3″-, 4・4″-, 2●3″-, 2・
4′-, or 3●4″-dimethylbenzophenonimine, 2-, 3-, or 4-chlorobenzophenonimine,
2-chloro-4-methylbenzophenonimine, 4-chloro-4''-methylbenzophenonimine, 4.4''-
Dichlorpenzophenonimine, 4-nitrobenzophenonimine, 2●4-, dinitropenzophenonimine, 4-hydroxybenzophenonimine, 4-N●N-
Dimethylaminobenzophenone imine, 4-acetylbenzophenone imine, 4-methoxycarbonylbenzophenone imine, 4-N●N-dimethylcarbamo, ylbenzophenone imine, 4-cyanobenzophenone imine, fluorenone imine, xanthone imine, anthrone imine, acridoimine Examples include. Benzophenone imines are usually produced by condensation of benzophenones and ammonia, and the imidation rate is usually 20
~50%. In carrying out the present invention, the target oxidizing liquid is one obtained by oxidizing benzophenone imines with molecular oxygen using dissolved copper as a catalyst, and contains benzophenone azines and unreacted benzophenone imines.

Specifically, for example, pentacopper halide as an oxidation catalyst,
In particular, oxidizing solutions using cuprous chloride (US Pat. No. 28702)
No. 06), oxidizing solution using copper (■) halide methoxide (JP-A-53-147047), using copper acetate, copper thiocyanide, copper cyanide, copper carbon, copper sulfate, copper nitrate, copper phosphate A reaction solution in which imines were oxidized by dissolving copper in an imine solution or an oxidation reaction solution in a different form from these copper salts (Japanese patent application Sho M-43490), 55-5261), or a reaction solution in which benzophenone, ammonia and molecular oxygen were brought into contact in the presence of cuprous chloride to produce azines 5 in one step (JP-A-52-7
94), and furthermore, an oxidation reaction solution using a polymer catalyst in which cuprous halide is coordinated with a resin having a monodentate pyridine as a functional group (Japanese Patent Application Laid-open No. 52-131987).

The present invention can be carried out immediately after the oxidation reaction without pretreating the oxidation reaction solution. In the present invention, since benzophenones act as a solvent, no particular solvent is required. However, when decomposing imines at a lower temperature than the oxidation reaction, azines may precipitate, A solvent can also be added to help maintain the reaction system in a solution state.

Particularly preferred are those that are thermally stable and have low viscosity. For example, benzene, toluene, 0-, m-, p-xylene, ethylbenzene, mesitylene, cumene, pseudocumene, amylbenzene, aromatic hydrocarbons having 6 to 16 carbon atoms and mixtures thereof, chlorobenzene, o-, m-, p-dichlorobenzene, nitrobenzene, o-, m-, p-dinitrobenzene, o-, m-, p-chlorotoluene, diphenyl, phenanthrene, anisol, diphenyl ether, acetophenone, benzyl, benzophenone, hexane, heptane , cyclohexane, cyclooctane, ethylcyclohexane, ethylene dichloride, tetrachlorethylene, diisopropyl ether, dipropylether, diisobutyl ketone, butyl acetate,
Examples include butyl benzoate, phenyl benzoate, dimethyl phthalate, and the like. There are no particular restrictions on the concentration of unreacted benzophenonimines remaining in the oxidation reaction solution, but
It is not necessarily a good idea to leave a large amount of the benzophenone imine unreacted in the oxidation reaction.

Conversely, if the amount of benzophenone imine in the oxidation reaction solution is very small, it is not an advantageous method in terms of energy cost and equipment cost to recover a small amount of ammonia by reacting with water. I can not say. That is, if the benzophenone imine is small, the oxidation reaction solution is subjected to the next step (copper recovery or hydrolysis of benzophenone azine with acid).
You can send it as is. Therefore, the amount of unreacted benzophenone imine in the acid 1 reaction solution, which can be carried out industrially advantageously, is 0.2 to 15% by weight, more preferably 0.5% by weight.
~1%. The carboxylic acids used as catalysts when decomposing the benzophenonimines include:
Aliphatic, alicyclic, aromatic and other carboxylic acids can be used, such as acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, pivalic acid, hydrofuric acid, nandoic acid, hydrofuric acid,
Pelargonic acid, puric acid, undecanoic acid, lauric acid, tridecanoic acid, silistic acid, palmitic acid, stearic acid, chloroacetic acid, bromoacetic acid, fluoroacetic acid, trichloroacetic acid, trifluoroacetic acid, glycolic acid, lactic acid, oxalic acid, malonic acid , succinic acid, adipic acid, maleic acid, malic acid, citric acid, azelaic acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, trimesic acid, nicotinic acid, isonicotinic acid, benzoic acid, tolylic acid, chlorobenzoic acid Examples include acid, nitrobenzoic acid, salicyl, anthranilic acid, glycine, alanine, methionine, and leucine.

Further, these carboxylic acids include those that produce carboxylic acids under reaction conditions even if they are not in the form of carboxylic acids at the time of addition. For example, it may be a compound that generates a carboxylic acid upon contact with water, or a compound that generates a carboxylic acid upon thermal decomposition. Examples of such compounds include:
Ammonium carboxylates, acid amides, nitriles, esters,
Examples include acid chloride. It may also be a compound that thermally decomposes to produce a carboxylic acid at the reaction temperature. Although there is no particular restriction on the amount of carboxylic acid used in the present invention, it is generally preferably 0.005 to 10 weight percent, particularly 0.02 to 2 weight percent, based on the oxidation reaction solution.

The reaction conditions in the present invention cannot be specified according to the activity of the imine decomposition catalyst, the reaction type, etc., but the reaction temperature is 60 to 350°C, preferably 80 to 30°C.
, more preferably 100 to 270°C.

The reaction pressure is also not particularly limited. Although it can be carried out under increased pressure or reduced pressure, normal pressure to 3 molar pressure is preferable. The reaction time varies depending on the activity of the catalyst, the concentration of unreacted imines in the oxidation reaction solution, the desired decomposition rate, etc., but is usually in the range of 0.1 to several tens of hours. There is no particular restriction on the reaction method in the present invention, and the reaction can be carried out either batchwise or continuously. There is no particular restriction on the water supply method in the present invention. It can be supplied to the reactor in a liquid state, or it can be heated in advance and sent to the reactor in a gaseous state. It is also possible to send water along with other gases. In this case, nitrogen, argon, helium, air, etc. can be used as the gas that entrains water. However, inert gases such as nitrogen, argon, helium, etc. are preferred. In the present invention, the amount of water supplied is not particularly limited, but is preferably 1 to 200 mol, more preferably 2 to 100 mol, per 1 mol of benzophenonimine to be decomposed.

In the present invention, it is desirable that ammonia generated by the decomposition of imines be continuously discharged from the system.

This ammonia is recovered as a liquid by cooling or pressurized cooling. If necessary, it can also be recovered by absorption in water. Benzophenones are recovered in a mixed form with benzophenone azines. Example 1 Benzophenone imine (benzophenone imine 23.5
%, the remainder being benzophenone) and 0.40 y of commercially available cuprous chloride (Koso Kagaku Co., Ltd.) were placed in a reactor, and while maintaining the temperature at 140'C, the mixture was blown into the bottom of the reactor. 400ml of pure oxygen from the mouth under normal pressure
9 powders were stirred.

Gas chromatography analysis of the reaction solution after powder 9 revealed that benzophenone azine was produced at a yield of 87''O% and a selectivity of 99%.

The amount of unreacted benzophenonimine was 2.85%.
After the oxidation reaction, 122 m9 of the reagent benzoic acid (Koso Chemical Co., Ltd.) was added as an imine decomposition catalyst, and the solution was maintained at 140°C under normal pressure through the inlet inserted into the bottom of the reaction vessel. Water was blown into the mixture as superheated steam at a rate of 4.5 y/hour, and the mixture was stirred for 1 hour.

After reacting for 1 hour, the reaction solution was analyzed by gas chromatography, and it was found that the benzophenone imine content had decreased to 0.23%.

Further, the generated ammonia was led out of the reactor, absorbed into water, and titrated with acid. As a result, ammonia equivalent to 92% of the decomposed amount of imine was determined. Example 2~? The results are shown in which oxidation was carried out in the same manner as in Example 1, and then unreacted benzophenone imine was decomposed using various carboxylic acids as catalysts.

Examples 35 to 37 Benzophenone imines were oxidized and decomposed in exactly the same manner as in Example 1.

However, the reaction was carried out by changing only the raw material benzophenones. The results were as shown in Table 2. Examples Feather benzophenone imine (benzophenone imine 124.
Charge 100g (0% remaining benzophenone) into the reactor, and insert it into the bottom of the skin reactor through the inlet port.
The temperature was increased while blowing pure oxygen at a rate of 250 ml and 11 minutes under normal pressure.

When the temperature reached 160°C, 100 m9 of commercially available monocopper formate (Kanto Kagaku Co., Ltd.) was added to the benzophenone imine solution, and the mixture was stirred at 160°C for 1 hour.

When the reaction solution was analyzed by gas chromatography,
Benzophenone azine was produced with a yield of 82% and a selectivity of 97%.

The amount of unreacted benzophenone imine was 3.70%.

Next, 122 m9 of benzoic acid was added, and the imine was decomposed in the same manner as in Example 1. Imine after reaction is 0.11
It was %.

Example 39 Benzophenone imine solution (Benzophenone imine 23.
6% and the remainder benzophenone) was charged into a reactor, and the temperature was raised to 140° C. while blowing oxygen gas.

After adding 2.0 f of commercially available metallic copper powder (Wako Pure Chemical Industries, Ltd.), the mixture was stirred for 3 hours under normal pressure while passing oxygen gas through the bottom of the reactor at a rate of 300 ml/min. Subsequently, copper powder was separated from the reaction solution using a glass filter (filter size G-4). At this point, the p liquid was analyzed by gas chromatography, and the yield was 92% benzophenone azine.
%, selection rate? It was generated in %. The amount of unreacted benzophenonimine was 1.44%. 100f of this deep liquid was charged into a pressurized container, and further 122m9 of nozoic acid was added.
An imine decomposition reaction was carried out in the same manner as in Example 1.

The imine content after the reaction was 0.08%.

Example 40 Benzophenone imine solution (Benzophenone imine 46.
7%, remaining benzophenone) 30 da, 0-dichlorobenzene (Kosou Kagaku Co., Ltd.) 30 f1 and cuprous chloride 0.5
0y was charged into a reactor, and while maintaining the temperature at 120° C., oxygen gas was blown into the reactor from the bottom at a rate of 300 ml/Imin, and the mixture was stirred.

Analysis of the reaction solution by gas chromatography revealed that benzophenone azine was produced in a yield of 85% and a selectivity of 99%.

The amount of unreacted benzophenonimine was 3.3%. Next, benzoic acid 617ri9 was added to this oxidizing solution, and it was blown into the solution from the bottom at a rate of 6.0y1hr under normal pressure in a steam state, and stirred at 120° C. for 1 hour.

The benzophenone imine content after the reaction was 0.16%.

Comparative Example 1 Benzophenone imine was oxidized under the same conditions as Example 1, yield of azine was 86.5%, and unreacted imine was 3.05%.
A reaction solution of %7 was obtained.

Imine decomposition was attempted under the same conditions as in Example 1 without adding any imine decomposition catalyst.

After 1 hour of reaction, the imine was 3.01%, which was hardly decomposed.

O Comparative Example 2 Benzophenone imine was oxidized under the same conditions as the Example feather,
A reaction solution was obtained in which the azine yield was 80% and the unreacted imine was 3.85%.

An attempt was made to decompose imine under the same conditions as in the example without adding any imine decomposition catalyst.

After 1 hour of reaction, the imine content was 3.63%, which was hardly decomposed.

Claims (1)

[Claims] 1. General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (However, in the above formula, R^1 and R^2 have 1 to 1 carbon atoms.
0 chain type, cyclic fatty acid or aromatic hydrocarbon group, and an ether group consisting of the hydrocarbon group, an acyl group, an acyloxy group, an alkoxycarbonyl group, a disubstituted amino group, and a halogen group, a hydroxy group, a nitro group, The same or different groups selected from the group consisting of cyano groups, or R^1 and R^2 may be taken together to represent a single bond or ring. Moreover, m and n are 0 or an integer of 1 to 5. ) is oxidized with molecular oxygen in the presence of a copper catalyst to produce benzophenone azines,
A method for recovering ammonia from benzophenone imines, which comprises reacting unreacted benzophenone imines remaining in the oxidizing solution with water in the presence of a carboxylic acid to recover ammonia.