JPH0354095B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel method for producing 3,4'-diaminobenzophenone. For more details, see the general formula () 3,4'-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. Relating to a manufacturing method. 3,4'-diaminobenzophenone is useful as a heat-resistant polymeric monomer, agricultural medicine, dye intermediate, etc., and is an important substance that is particularly used as a raw material for heat-resistant polyamides and polyimides. 3,4′-diaminobenzophenone is conventionally
A method for producing it by reducing 3,4'-dinitrobenzophenone is known. However, 3,
No method has been found for industrially producing 4'-dinitrobenzophenone at low cost. As a method for producing 3,4'-dinitrobenzophenone, for example, 3,4'-dinitrophenylmethane is obtained from 4-nitrobenzyl alcohol and nitrobenzene,
A method of manufacturing it by oxidizing it with chromic acid (P.
J. Montagne et al., Ber., 49 2293-2294 (1916)),
Nitrate diphenyl acetic acid with fuming nitric acid 3.
A method for producing 4'-dinitrodiphenylacetic acid and oxidizing it with chromic acid (I.Moyer.
Hunsberger et al., J. Am, Chem, Soc., 71 2635
2639 (1949)), a method for producing 4-nitrobenzophenone by nitration (Vernon. L. Bell et al., J.
Polymer, Chem., 14 2277 (1976)). However, these methods involve complicated reactions, require repeated recrystallization and purification to remove large amounts of by-products such as isomers, and require a large amount of processing time for waste acids and waste metals. There are drawbacks such as the expense involved. Therefore, 3,4′−
It is extremely difficult to industrially produce 3,4'-diaminobenzophenone using dinitrobenzophenone as a raw material. The present inventors have proposed 3.
A method for producing 4'-diaminobenzophenone was intensively investigated. As a result, we used 4-halogeno-3,4'-dinitrobenzophenone, which can be easily produced by nitration of 4-halogeno-4'-nitrobenzophenone, as a raw material, and used it as a reduction catalyst and dehydrohalogenating agent. It was discovered that 3,4'-diaminobenzophenone can be produced in high yield by catalytic reduction and dehalogenation in the presence of the compound, 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 dehydrohalogenation agent to produce 3,4'-diaminobenzophenone. This is a method of manufacturing. 4-halogeno-3 used in the method of the invention,
4'-Dinitrobenzophenone can be easily produced by nitration of 4-halogeno-4'-nitrobenzophenone obtained by condensation of paranitrobenzoyl chloride and halogenobenzene (PJ Montagne et al., Ber., 49 ). 2267～2270
(1916), GSMironov et al., J.Org.Chem.of
USSR, 8 1538-1543 (1972)). On the other hand, although reduction of 4-halogeno-3,4'-dinitrobenzophenone is known, the reduction product is 4-halogeno-3,4'-diaminobenzophenone or 3,4'-diaminobenzophenone. hydrol (PJ Montagne et al., Ber., 49 2268~
2271 (1916)). In this way, in the reduction of 4-halogeno-3,4'-dinitrobenzophenone, the nitro group is reduced to an amino group, and depending on the reaction conditions and reducing agent, the dehalogenation reaction may also proceed along with the reduction. However, the carbonyl group of benzophenone is further reduced to a benzhydrol compound. That is, producing 3,4'-diaminobenzophenone from 4-halogeno-3,4'-dinitrobenzophenone, and producing 4-halogeno-3,
In the reduction of 4'-dinitrobenzophenone, there is no known method for suppressing the reduction reaction of the carbonyl group and allowing only the reduction of the nitro group to an amino group and the dehalogenation reaction to proceed. This is a new method for industrially producing 3,4'-diaminobenzophenone. The raw material used in the method of the present invention is 4-halogeno-3,4'-dinitrobenzophenone represented by the above general formula (), in which the halogen atom represented by X is chlorine, bromine, iodine,
Any type of fluorine can be used. For example, 4-
Chloro-3,4'-dinitrobenzophenone, 4-
Bromo-3,4'-dinitrobenzophenone, 4-
Iodo-3,4'-dinitrobenzophenone, 4-
Examples include fluoro-3,4'-dinitrobenzophenone. 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 for catalytic reduction, e.g.
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 also used as Raney catalysts. It will be done. The amount of catalyst used is in the range of 0.01 to 10% by weight as a metal based on the raw material 4-halogeno-3,4'-dinitrobenzophenone, and usually 2 to 8% when used in the metal state.
% by weight, in the range of 0.1 to 5% by weight when attached to a carrier. 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 dehydrohalogenating agent used is
Normal for 3,4'-dinitrobenzophenone
It is used in an amount of 0.5 to 3 times the mole, preferably 1 to 2 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 hydrocarbons such as 1,2-trichloroethane and tetrachloroethane, N,N-dimethylformamide, dimethylsulfoxide, etc. 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 to be used is sufficient to suspend or completely dissolve the raw material 4-halogeno-3,4'-dinitrobenzophenone, and is not particularly limited. 0.5 to 10 times the weight is sufficient. 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, 4
-Halogeno-3,4'-dinitrobenzophenone is dissolved or suspended in a solvent, a reduction catalyst is added, and then hydrogen is introduced at a predetermined temperature under stirring to reduce the nitro group. After that, a dehydrohalogenation agent is added and the dehalogenation reaction is subsequently performed, or a dehydrohalogenation agent is added at the time of addition of the reduction catalyst and hydrogen is introduced at a predetermined temperature under stirring to reduce the nitro group. Examples include a method of simultaneously carrying out a dehalogenation reaction. In either case, the reaction proceeds smoothly and the desired product, 3,4'-diaminobenzophenone, can be produced. However, since the halogen atom at the 4-position of the raw material 4-halogeno-3,4'-dinitrobenzophenone has nucleophilicity, it may cause a side reaction with the dehydrohalogenating agent depending on the conditions. , may reduce the yield of the target product, so the method is preferred. The progress of the reaction can be followed by stoichiometric hydrogen uptake or by thin layer chromatography. The reaction solution obtained by the above method was heated to
Alternatively, after removing the catalyst and inorganic salt by extraction or the like, concentration is performed as necessary to precipitate 3,4'-diaminobenzophenone as crystals. Alternatively, 3,4'-diaminobenzophenone can be isolated 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 3,4'-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,
4-bromo-3,4'-dinitrobenzophenone
105g (0.3mol), 5% palladium/activated carbon catalyst (Japan Engelhard Co., Ltd.) 5g and dioxane
When hydrogen is introduced while stirring at a temperature of 70 to 80℃, 41 (1.83
mol) of hydrogen was absorbed. Next, after cooling until the internal temperature reaches 30℃, 38.5g of 30% ammonia water
(0.33 mol) and then introduced hydrogen while stirring at a temperature of 30 to 40°C. In 7 hours, 7.2
(0.32 mol) was absorbed. The reaction solution was filtered at the same temperature to remove the catalyst, and when allowed to cool, 3,4'-diaminobenzophenone was precipitated as yellow crystals. The crystals were filtered, washed with 30 ml of 50% dioxane aqueous solution, and dried. Yield 58g (yield 91%) Melting point 121-123℃ Elemental analysis C H N Calculated value (%) 73.5 5.7 13.2 Measured value (%) 73.1 6.0 13.1 Examples 2-7 Raw material 4-halogeno-3,4'- Example 1 except that the type of dinitrobenzophenone, the type and amount of catalyst used, the type and amount of solvent used, the type and amount of dehydrohalogenation agent, reaction temperature and pressure were changed as shown in Table 1. The reaction was carried out in the same manner as above to obtain the desired product. The results are shown in Table-1.

[Table] Example 8 In a glass sealed container equipped with a thermometer and a stirrer,
-Chloro-3,4'-dinitrobenzophenone 30.7
(0.1 mol), 1 g of palladium black catalyst, and 300 ml of benzene were charged, and hydrogen was introduced while stirring at a temperature of 65 to 70°C, and 13.3 (0.59 mol) of hydrogen was absorbed in about 9 hours. next,
Add 45 g (0.12 mol) of a 15% caustic potassium aqueous solution and 2 g of a 90% trioctylmethylammonium chloride aqueous solution (Tokyo Kasei Reagent), and then
Hydrogen was introduced with stirring at a temperature of 235°C (0.105 mol) in about 6 hours. After filtering the reaction solution at the same temperature to remove the catalyst, the organic layer of the filtrate 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 filtered, washed with 50 ml of benzene, and dried to obtain crystals of 3,4'-diaminobenzophenone hydrochloride. Yield: 23.4g (yield: 82%)
Recrystallization from 20% aqueous isopropanol yielded pure pale yellow needle crystals. Elemental analysis with melting point of 250°C or higher C H N Cl Calculated value (%) 54.7 4.9 9.8 24.9 Measured value (%) 54.3 5.4 9.7 24.8 Example 9 4-chloro-3,4'-dinitrobenzophenone
30.7 g (0.1 mole), 10.6 g (0.1 mole) of sodium carbonate, 1 g of 5% palladium/alumina catalyst (Japan Engelhard Co., Ltd.) and 250 ml of 1,2-dichloroethane were charged into an autoclave. Hydrogen was introduced with stirring in a temperature range of 30 to 35°C, and the reaction was carried out for 10 hours while constantly maintaining the pressure at 10 kg/cm ² ·G. After the reaction was completed, the reaction mixture was heated to 70°C and heated to remove the catalyst and inorganic salt. By cooling, 3,4'-diaminobenzophenone was obtained as yellow needle-like crystals. Separate the crystals and add 20 ml of 1,2-dichloroethane.
Washed and dried. Yield: 17.6 g (yield: 83%), melting point: 121-122° C. Recrystallization from ethanol gave pure yellow needle-like crystals. Melting point 122-122.5℃.

Claims (1)

[Claims] 1 General formula () 3,4'-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.