JPS58121256A - Preparation of 3,3'-diaminobenzophenone - Google Patents

Abstract

PURPOSE:To obtain the titled compound useful as a monomer for heat-resistant polymers, etc. industrially and advantageously in high yield at a low cost, by catalytically reducing and dehalogenating an easily preparable benzophenone in the presence of a reduction catalyst and a dehydrohalogenating agent. CONSTITUTION:A benzophenone compound of the formula (X and Y are halogen), e.g. 3,3'-dinitro-4,4'-dichlorobenzophenone, is catalytically reduced and dehalogenatd in the presence of a reduction catalyst, e.g. Pd or Ni, and a dehydrohalogenating agent, e.g. CaCO3, NaOH or MgO, to give 3,3'-diaminobenzophenone. The method of reaction is advantageous since the raw material compound of the formula is easily obtained by nitrating a 4,4'-dihalogenobenzophenone. The method is suitable for an industrial method of preparing the aimed compound from the following advantages: No environmental pollution by wastes, and the isolated product has a high purity without requiring troublesome purification steps.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for producing 6,3'-diaminobenzophenone. More specifically, a benzophenone compound represented by the general formula (1) (in which X and Y are the same or different) and a halogen atom) is subjected to catalytic reduction and dehalogenation in the presence of a reduction catalyst and a dehydrohalogenating agent. The present invention relates to a method for producing 6°3'-diaminobenzophenone, which is characterized by the step of:

3.3'-Diaminobenzophenone is useful as a heat-resistant polymer monomer, agricultural medicine, dye intermediate, etc., and is an important substance that is a raw material for heat-resistant polyamides and polyimide resins in particular. Conventionally, 6,3'-diaminobenzophenone is produced by reducing 6,3'-dinitrobenzophenone obtained by nitrating benzophenone. In this method, since the reaction product obtained by nitration of benzophenone is a mixture containing isomers, a large amount of solvent is used to isolate 3,3'-dinitrobenzophenone, and recrystallization is required. Purification must be repeated (E; Barnatt et al., J.

- The yield of dinitrobenzophenone is greatly reduced, and it is not economical because it requires complicated steps such as recovering the solvent used for purification and disposing of the residue. The disadvantage is that it is not suitable for industrial scale production. Furthermore, in order to produce 6,3'-sicaminobenzophenone from 3,6'-dinitrobenzophenone, a large excess of stannous chloride is used in a large amount of concentrated hydrochloric acid to perform phosphor reduction (L, H, Klerrm et al., J, ○rg, Chem 23551 (195B)
).

However, tin compounds are expensive and have problems such as antimetal and waste acid treatment, making them extremely disadvantageous for industrial use from both economical and environmental protection points of view.

The present inventors have made extensive studies on a method for producing 6°6'-diaminobenzophenone that does not have the above-mentioned drawbacks. As a result, it can be easily produced by nitration of 4,4'-di-logenobenzophenone; It was discovered that 6,6'-diaminobenzophenone can be produced in high yield by catalytic reduction and dehydrogenation in the presence of a reduction catalyst and a dehydrogenation agent, and the present invention completed the method.

, that is, the method of the present invention is based on the general formula (1) (wherein, Xl
A method for producing 6゜6'-diaminobenzophenone by catalytic reduction and dehalogenation of a benzophenone compound represented by (Y represents the same or different halogen atoms) in the presence of a reduction catalyst and a dehydrohalogenating agent. be.

3, Durge Nitro-4゜4'- used in the method of the present invention
Dihalogenobenzophenones are easily produced by nitration of 4,4'-diaminobenzophenones.

For example, when 4,4'-dichlorobenzophenone is nitrated with a mixed acid, 3,3'-dinitro-4゜dichlorobenzophenone is obtained in a yield of 95-98% (
E, R, Kofanov et al., J, Org, Chern.
of USSR 1598-100 (1979)).

For this 6,6'-dinitro-4,4'-dino logenobenzopheno/, 3,3'-dinitro-4°4'
-dichlorobenzophenone or 3,3'-hydro-4,4'-dibromobenzophenone in hydrochloric acid,
The corresponding 6,6'-diaminor 4,4'-dino-10genobenzophenone can be produced by reduction using zinc chloride, and 3,3'-dinitro-4,4'-
It is known that 3,3'-diaminobenzohydrol can be obtained by reducing dibromobenzophenone with sodium amalgam (Ber 481027 (1)
915) ).

In this way, in the reduction of 3,3'-dinitro-4,41-dinologenopenzophenone, the nitro group is reduced to an amine group. Although the reaction proceeds, it is known that the carbonyl group of benzophenone is further reduced to a benzohydrol compound.

However, it is possible to prepare 6,3'-diaminobenzophenone from 6,3'-dinitro-4,4'-dihalogenobenzophenone, and 6,3'-dini) o -
In the reduction of 4,4'-cyhalogenobenzophenone,
There is no known method for suppressing the reduction reaction of carbonyl groups and allowing only the reduction of nitro groups to amine groups and the deno-logogenation reaction to proceed. This is a new method that can be manufactured with ease.

The raw material used in the method of the present invention is 6,3'-dinitro-4,4'-dinologenobenzophenone represented by the general formula (1), wherein ,
The chlorine atom represented by Y may be chlorine, fluorine, iodine, or bromine. For example, 6゜6'-dinitro-4,4'-dichlorobenzophenone, 3,3'-dinitro-4,4'-dibromobenzophenone, 3,6'-
Dinitro-4,4'-difluorobenzophenone, 3.
6'-dinitro-4,4'-short benzophenone,
5.3'-dinitro-4-chloro-4'-bromobenzophenone, s,s'-dinitro-4-chloro-4'
- Examples include those in which the halogen species are the same or different, such as iodobenzophenone. Among these, those in which the halogen is a chlorine atom are industrially advantageously used.

The reduction catalyst used in the method of the present invention includes metal catalysts commonly used in catalytic reduction, such as nickel,
Palladium, platinum, rhodium, ruthenium, cobalt,
Copper etc. can be used.

Industrially it is preferred to use palladium catalysts. Although these catalysts can also be used in the metallic state,
Usually used by adhering to the surface of a carrier such as carbon, barium sulfate, silica gel, alumina, etc.
Cobalt, copper, etc. are also used as Raney catalysts. The amount of catalyst used is 0.0% as metal based on the raw material 6,3'-dinitro-4,4'-dihalogenobenzophenone.
It is in the range of 1 to 10% by weight, usually 2 to 8% by weight when used in a metal state, and 0% when attached to a carrier.
It ranges from 1 to 5% by weight.

Examples of the dehydrohalogenation agent used in the method of the present invention include alkali metal or alkaline earth metal oxides, hydroxides, carbonates, bicarbonates, or ammonia/or common organic amines. . For example, calcium carbonate, sodium hydroxide, magnesium oxide, ammonium bicarbonate, calcium oxide, lithium hydroxide, barium hydroxide, potassium carbonate, potassium hydroxide, ammonia, triethylamine, tri-n-butylamine, triethanolamine, pyridine and N - Methylmorpholine is mentioned. If necessary, 92 or more types of these dehydrohalogenation agents may be mixed. The amount of the dehydrohalogenating agent to be used is usually O,S to 5 times the mole, preferably 2 to 5 times the mole of 6,6'-dinitro-4'4'-dihalogenobenzophenone as the raw material.
~3 times the molar amount is used.

The method of the invention typically uses a reaction solvent.

The reaction solvent is not particularly limited as long as it is inert to the reaction, and includes, for example, alcohols such as methanol, isopropyl alcohol, glycols such as ethylene glycol and fluoropylene gelol, Ethers such as ether, dioxa/, tetrahydrofuran, methyl cellosolve, aliphatic hydrocarbons such as hexane, cyclohexane, aromatic hydrocarbons such as benzene, toluene, xylene, esters such as ethyl acetate, butyl acetate, dichloromethane, Halogenated hydrocarbons such as chloroform, carbon tetrachloride, 1,2-dichloroethane, 1.1.2-trichloroethane, and tetrachloroethane, N,N-dimethylformamide, dimethylsulfoxide, and the like can be used. Note that when using a reaction solvent that is immiscible with water, if the reaction progresses slowly, it can be accelerated by adding a commonly used phase transfer catalyst such as a quaternary ammonium salt or a quaternary phosphonium salt.

The amount of solvent used is 3,3'-dinitro-4°47 of the raw material.
- An amount sufficient to suspend or completely dissolve the dihalogenobenzophenone is sufficient. Although not particularly limited, an amount of 0.5 to 10 times the weight of the raw material is usually sufficient.

The reaction temperature is not particularly limited. Generally 20-200
A range of 0.degree. C., particularly a range of 20 to 100.degree. C. is preferred.

In addition, the reaction pressure is usually normal pressure to 5 D Ky/t:
! -G level.

In a general embodiment of the method of the present invention, (1) a reduction catalyst is added to 6゜dinitro-4,4'-dinologenobenzophenone dissolved or suspended in a solvent, and then, with stirring, After introducing hydrogen at a predetermined temperature to reduce the nitro group, add a dehydrohalogenation agent and continue the dehalogenation reaction, or An example of this method is to introduce hydrogen at a predetermined temperature under stirring to simultaneously perform the reduction of the nitro group and the dehalogenation reaction. In either case, the reaction proceeds smoothly and the desired product, 6,6'-diaminobenzophenone, can be produced. However, the raw material 6,
Since the halogen atom at the 4,4'-position of 37-sinitro 4,4'-dihalogenobenzophenone has nucleophilicity, it may cause a side reaction with the dehydrohalogenating agent depending on the conditions, resulting in a reduction in the yield of the target product. Method (2) is preferable because it may lower the rate.

The progress of the reaction can be followed by stoichiometric hydrogen uptake or by thin layer chromatography. After the catalyst and inorganic salts are removed from the reaction solution obtained by the above method by heating or extraction, concentration is performed as necessary to precipitate 3,3'-diaminopenzophenone as crystals. Alternatively, 3,3'-diaminobenzophenone can be isolated as a hydrochloride by blowing hydrogen chloride gas into the reaction solution from which the catalyst and inorganic salt have been removed.

The method of the present invention is a method for producing 3,5'-diaminobenzophenone at a high yield and at a low cost, and there is no problem of environmental pollution caused by wastes associated with conventional methods, and the purity of the isolated product is high. It is expensive and does not require complicated purification processes, etc.
This is suitable as an industrial manufacturing method.

Hereinafter, the present invention will be explained in more detail using examples.

Example 1 3, Gooji nitro-4,4'-cyclobene/sophenone 509 (0.15 mol), calcium oxide 21r (03
8 mol), 5% palladium, um/alumina catalyst (Japan Engelhard Co., Ltd.) 1 g and 1,2-dichloroethane 65
0d into the autoclave.

In the temperature range of 30 to 65°C, hydrogen is introduced while stirring and the pressure is constantly maintained at 10 Ky/cr/l-G.
The reaction was carried out for 10 hours while maintaining the temperature. After the reaction was completed, the reaction mixture was heated to 70° C. and heated to remove the catalyst and inorganic salt. Leave it to cool.

3'-diaminobenzophenone was obtained as yellow needles. The crystals were washed daily with 10 d of 1,2-dichloroethane and then dried.

Yield 21.2 F (67% yield), melting point 149-15
Recrystallization from 0.5°C ethanol gave pure yellow needle crystals. Melting point 150-151℃ Elemental analysis HN Calculated value (%) 73.5 5,7 13.2 Measured value (
@ 73.4 6.0 12.7 Example 2 In a glass green sealed container equipped with a thermometer and a stirrer, 3.5'
-dinitro-4,4'-dichlorobenzophenone 1o2
f (0.3 mol), 5th palladium/activated carbon catalyst (Japan Engelhardt Co., Ltd.) 5f, and 300 mJ of dioxane, and hydrogen was introduced with stirring at a temperature of 70 to 80°C. t (1,85
mol) of hydrogen was absorbed. Next, 8 D f (0,8 mol) of a 40% aqueous solution of caustic soda was added, followed by 7
When hydrogen is introduced while stirring at a temperature of 0 to 80℃,
13.8 t (0.62 mol) was absorbed in 6 hours.

The catalyst was removed by passing the reaction solution at the same temperature, and when it was allowed to cool, 6,3'-diaminobenzophenone was precipitated as yellow needle-like crystals. Daily crystals, 50 thidioxane aqueous solution 30
After washing with m1, it was dried. Yield 59.2 f (yield 9
3%) Melting point: 149-151°C Examples 5 to 10 Type of raw material 6,6'-dinitro-4,4'-dihalogenobenzophenone, type and amount of catalyst used, type and amount of solvent used, dehalogenation The reaction was carried out in the same manner as in Example 2, except that the type and amount of hydrogen agent used, reaction temperature and pressure were changed as shown in Table 1 to obtain the desired product.

The results are shown in Table-1.

Example 11 6°s'-
Dinitro-4-chloro-da-fluorobenzophenone 4
9f (0.15 mol), 1v of palladium black catalyst and 300ml of benzene were charged and hydrogen was introduced with stirring at a temperature of 65-70°C.
0.2 t (0.9 mol) of hydrogen was absorbed.

Next, 180 f (0,
45 mol) and trioctylmethylammonium chloride 90% aqueous solution (Tokyo Kasei Reagent) 61 were added, and hydrogen was subsequently introduced while stirring at a temperature of 65 to 70°C, resulting in 7.41 (0.35 mol) in about 5 hours. Absorbed. After the reaction solution is passed through the mouth at the same temperature to remove the catalyst, the organic layer of the mouth liquid is separated.

Magnesium sulfate was added to the organic layer for dehydration, and then dry hydrogen chloride gas was blown into the organic layer until it was fully saturated. The precipitated crystals were washed with 50 ml of benzene every day and then dried to obtain crystals of 6,6'-diaminobenzophenone hydrochloride. Yield: 55.29 (yield: 89%) Recrystallized from 20% hydrated isoglobanol to obtain pure pale yellow needle crystals.

Melting point 265-267°C (decomposition) Elemental analysis CHN CL Calculated value (%) 54.7 4.9 9,8 24.
9 Measured value (ch) 54.2 5.1 9,7 25
．． 1 Patent applicant Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Claims] Catalytic reduction and dehalogenation of a benzophenone compound represented by general formula (1) (in the formula, X1Y represents the same or different halogen atoms) in the presence of a reduction catalyst and a dehydrohalogenating agent. A method for producing 6°6'-diaminobenzophenone, the method comprising: