JPH0415218B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel method for producing 3,3'-diaminobenzophenone. For more details, see the general formula () 3,3'-diaminobenzophenone characterized by catalytic reduction and dehalogenation of a benzophenone compound represented by (wherein, X represents a halogen atom) in the presence of a reduction catalyst and a dehydrohalogenating agent. Relating to a manufacturing method. 3,3'-diaminobenzophenone is useful as a heat-resistant polymeric monomer, agricultural medicine, dye intermediate, etc., and is an important substance that is a raw material for heat-resistant polyamides and polyimide resins. Conventionally, 3,3'-diaminobenzophenone is produced by reducing 3,3'-dinitrobenzophenone obtained by nitrating benzophenone. In this method, the reaction product obtained by nitrating benzophenone is a mixture containing isomers, etc., and a large amount of solvent is used to isolate 3,3'-dinitrobenzophenone from the reaction product. , recrystallization purification must be repeated [E.
Barnatt et al., J.chem.Soc125 767 (1924)]. As a result, the yield of 3,3'-dinitrobenzophenone has decreased significantly, and it is not economical because it requires complicated steps such as recovering the solvent used for purification and disposing of the residue. , 3,3'-dinitrobenzophenone has the disadvantage of not being suitable for production on an industrial scale. Furthermore, in order to produce 3,3'-diaminobenzophenone from 3,3'-dinitrobenzophenone, reduction was carried out with a large excess of stannous chloride in a large amount of concentrated hydrochloric acid (LH
Klemm et al., J.Org, Chem23 351 (1958). However, there are problems such as the high cost of tin compounds and the treatment of waste metals and waste acids, making this method extremely disadvantageous from the viewpoint of economic efficiency and environmental protection. The present inventors have proposed 3.
A method for producing 3'-diaminobenzophenone was intensively investigated. As a result, 3, which can be easily produced by nitration of 4-halogenobenzophenone,
Using 3'-dinitro-4-halogenobenzophenone as a raw material, 3,3'-diaminobenzophenone is produced in high yield by catalytic reduction and dehalogenation in the presence of a reduction catalyst and a dehydrohalogenating agent. It was discovered that phenone can be produced, and the method of the present invention was completed. That is, the method of the present invention is based on the general formula () (wherein, X represents a halogen atom) is catalytically reduced and dehalogenated in the presence of a reduction catalyst and a dehydrohalogenating agent to produce 3,3'-diaminobenzophenone. This is a method of manufacturing. 3,3'-dinitro-4 used in the method of the invention
- Halogenobenzophenones are easily produced by nitration of 4-halogenobenzophenones. For example, when 4-chlorobenzophenone is nitrated with sodium nitrate and concentrated sulfuric acid, 3,
3'-dinitro-4-chlorobenzophenone is 96~
obtained with a yield of 98% [GSMironov et al., J.Org.
Chem of USSR, 8 1538 (1972)]. However, there is no known method for producing 3,3'-diaminobenzophenone from 3,3'-dinitro-4-halogenobenzophenone. This is a new method for industrially manufacturing. The raw material used in the method of the present invention is 3,3'-dinitro-4-halogenobenzophenone represented by the above general formula (), in which the halogen atom represented by X is chlorine, fluoride, etc. , iodine, and bromine can be used. for example,
3,3'-dinitro-4-chlorobenzophenone,
3,3'-dinitro-4-bromobenzophenone,
Examples include 3,3'-dinitro-4-fluorobenzophenone and 3,3'-dinitro-4-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 be used in the metal state, they are usually used by being attached to the surface of a carrier such as carbon, barium sulfate, silica gel, or alumina, and nickel, cobalt, copper, etc. are used as Raney catalysts. It's okay. The amount of catalyst used is 0.01 to 10% by weight of the metal based on the raw material 3,3'-dinitro-4-halogenobenzophenone.
It is usually in the range of 2 to 8% by weight when used as a metal, and 0.1% when attached to a carrier.
~5% by weight. The dehydrohalogenating agents used in the process of the invention include alkali metal or alkaline earth metal oxides, hydroxides, carbonates, bicarbonates, or ammonia or the usual 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. Two or more of these dehydrohalogenating agents may be mixed if necessary. The amount of the dehydrohalogenating agent used is usually the same amount as the raw material 3,3'-dinitro-4-halogenobenzophenone.
It is used in an amount of 0.5 to 3 times the mole, preferably 1 to 1.5 times the mole. 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 examples thereof include alcohols such as methanol, ethanol, and isopropyl alcohol, glycols such as ethylene glycol and propylene glycol, ether, dioxane, Ethers such as tetrahydrofuran and methyl cellosolve, aliphatic hydrocarbons such as hexane and cyclohexane, aromatic hydrocarbons such as benzene, toluene and xylene, esters such as ethyl acetate and butyl acetate, dichloromethane, chloroform, carbon tetrachloride , 1,2-dichloroethane, 1,
Halogenated carbons such as 1,2-trichloroethane and tetrachloroethane, N,N-dimethylformamide and dimethylsulfoxide can be used. If the reaction progresses slowly when using a reaction solvent that is immiscible with water, it can be accelerated by adding commonly used phase transfer catalysts such as quaternary ammonium salts and quaternary phosphonium salts. I can do it. The amount of solvent used is based on the 3,3'-
An amount sufficient to suspend or completely dissolve the dinitro-4-halogenobenzophenone is sufficient, and although not particularly limited, it is usually sufficient to use 0.5 to 10 times the weight of the raw material. The reaction temperature is not particularly limited. Generally 20~
A range of 200°C, especially 20-100°C is preferred. Also,
The reaction pressure is usually about normal pressure to 50 kg/cm ² ·G. As a general embodiment of the method of the invention,
A reduction catalyst is added to a state in which 3,3'-dinitro-4-halogenobenzophenone is dissolved or suspended in a solvent, and then hydrogen is introduced at a predetermined temperature under stirring to reduce the nitro group. After cooling, add a dehydrohalogenation agent and continue the dehalogenation reaction, or add the dehydrohalogenation agent when adding the reduction catalyst and then introduce hydrogen at a predetermined temperature with stirring to reduce the nitro group. Examples of methods include performing a dehalogenation reaction and a dehalogenation reaction at the same time. In either case, the reaction proceeds smoothly and the desired product, 3,3'-diaminobenzophenone, can be produced. However, since the 4-position halogen atom of the raw material 3,3'-dinitro-4-halogenobenzophenone has nucleophilicity, it may cause a side reaction with the dehydrohalogenating agent depending on the conditions. The method is preferred because it may reduce the yield of the target product. The progress of the reaction can be followed by stoichiometric hydrogen uptake or by thin layer chromatography. After removing the catalyst and inorganic salt from the reaction solution obtained by the above method by heating, extraction, etc., the reaction solution is concentrated as necessary.
3'-diaminobenzophenone is precipitated as crystals. It is also possible to isolate 3,3'-diaminobenzophenone as a hydrochloride by blowing hydrogen chloride gas into the reaction solution from which the catalyst and inorganic salts have been removed. The method of the present invention enables the production of 3,3'-diaminobenzophenone in high yield and at low cost, without the problems of environmental pollution caused by wastes associated with conventional methods, and in addition, It is suitable as an industrial production method because it has high purity and does not require complicated purification steps. Hereinafter, the present invention will be explained in more detail with reference to Examples. Example 1 In a glass sealed container equipped with a thermometer and a stirrer,
3,3'-dinitro-4-bromobenzophenone
105.3g (0.3 mol), 5g of 5% palladium/activated carbon catalyst (Japan Engelhard Co., Ltd.) and 300ml of dioxane were charged, and hydrogen was introduced with stirring at a temperature of 70 to 80°C for about 8 hours 40.5
(1.81 mol) of hydrogen was absorbed. Next, 33 g (0.33 mol) of a 40% caustic soda aqueous solution was added, and hydrogen was introduced while stirring at a temperature of 70 to 80°C, and 7.2 (0.32 mol) was absorbed in 3 hours. The reaction solution was filtered at the same temperature to remove the catalyst, and when allowed to cool, 3,3'-diaminobenzophenone was precipitated as yellow needle-like crystals. The crystals were filtered, washed with 30 ml of 50% dioxane aqueous solution, and dried. Yield 59.2
g (Yield 93%) Melting point 149-150℃ Examples 2 to 7 Type of raw material 3,3'-dinitro-4-halogenobenzophenone, type and amount of catalyst used, type and amount of solvent used, removal The reaction was carried out in the same manner as in Example 1, except that the type and amount of the hydrogen halide agent, reaction temperature and pressure were changed as shown in Table 1 to obtain the desired product. The results are shown in Table-1.

[Table] Example 8 3,3'-dinitro-4-chlorobenzophenone 46 was placed in a glass sealed container equipped with a thermometer and a stirrer.
(0.15 mol), 1 g of palladium black catalyst and 300 ml of benzene were charged, and hydrogen was introduced with stirring at a temperature of 65 to 70°C, and 20.2 (0.9 mol) of hydrogen was absorbed in about 6 hours. Next, 79g (0.2mol) of 35% potassium carbonate aqueous solution
and trioctylmethylammonium chloride
3 g of a 90% aqueous solution (Tokyo Kasei Reagent) was added, and hydrogen was introduced while stirring at a temperature of 65 to 70°C, and 3.4 (0.15 mol) was absorbed in about 3 hours. After filtering the reaction solution at the same temperature to remove the catalyst,
Separate the organic layer of the filtrate. 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 filtered, washed with 50 ml of benzene, and dried to obtain crystals of 3,3'-diaminobenzophenone hydrochloride. Yield: 31.9 g (yield: 75%) Recrystallization from 20% aqueous isopropanol gave pure pale yellow needle crystals. Melting point 267℃ (decomposition) Elemental analysis C H N Cl Calculated value (%) 54.7 4.9 9.8 24.9 Measured value (%) 54.0 5.2 9.6 24.7 Example 9 3,3'-dinitro-4-chlorobenzophenone
46 g (0.15 mol), 11.2 g (0.2 mol) of calcium oxide, 1 g of 5% palladium/alumina catalyst (Japan Engelhard Co., Ltd.) and 1,2-dichlorothane.
Charge 250ml to the autoclave. Hydrogen was introduced with stirring in a temperature range of 30 to 35°C, and the reaction was carried out for 7 hours while constantly maintaining the pressure at 10 kg/cm ² ·G. After the reaction is complete, the reaction mixture is heated to 70°C.
The catalyst and inorganic salts were removed by raising the temperature to . By cooling, 3,3'-diaminobenzophenone was obtained as yellow needle-like crystals. The crystals were filtered, washed with 20 ml of 1,2-dichloroethane, and then dried. The yield was 24.8 g (yield 78%), and the product was recrystallized from ethanol with a melting point of 149-150°C to obtain pure yellow needle-like crystals. Melting point 150-151℃ Elemental analysis C H N Calculated value (%) 73.5 5.7 13.2 Measured value (%) 72.9 6.2 13.1

Claims (1)

[Claims] 1 General formula () 3,3'-diaminobenzophenone characterized by catalytically reducing and dehalogenating a benzophenone compound represented by (wherein, X represents a halogen atom) in the presence of a reduction catalyst and a dehydrohalogenating agent. manufacturing method.