JPS60239450A - Preparation of benzophenonazine - Google Patents

Abstract

PURPOSE:To obtain the titled compound useful as an intermediate for synthesizing hydrazine in high yield, by bringing benzophenonimine into contact with molecular oxygen in the presence of a complex compound of copper, a compound containing a pyridine skeleton, and formic acid. CONSTITUTION:Benzophenonimine is brought into contact with molecular oxygen in the presence of a complex compound of copper, a pyridine skeleton-containing compound (e.g., pyridine, or isoquinoline), and formic acid, to give benzophenonazine. The copper complex has the pyridine skeleton-containing compound and formic acid as ligands is extremely stable to oxidation with oxygen, and can keep high activity. It is considered that the complex keeps copper in an activated state by a lone electron pair of aromatic nitrogen atom of the pyridine, and this phenomenon is not found in a mere dissolved copper. An amount of the complex used is 1/200-1/2,000mol based on 1mol benzophenonimine, a very small amount of it shows high activity and shows no reduction in activity.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for producing benzophenone azine.

(Prior Art) Benzo7ene/enazine is an extremely useful substance as an intermediate for the production of hydranone, and many methods of oxidizing benzophenone imine in the presence of a catalyst have been reported.

Among these, the copper halide catalyst of U.S. Patent No. 2870206 and the copper halide methoxide catalyst of JP-A-53-147047 use a large amount of catalyst, 1 to 17,100 mol per 1 mol of benzophenone imine, and when used repeatedly. However, it is difficult to recover and separate the catalyst, and furthermore, the presence of halides causes corrosion of equipment, which is disadvantageous from an industrial perspective.

Also, in Japanese Patent Publication No. 58-28871, copper metal was used as a catalyst.
A method is disclosed in which benzophenone azine is obtained in a high yield by using dissolved copper obtained by dissolving cuprous oxide etc. in an amount of i/100 to 172,000 mol per 1 mol of benzophenone imine, but this method is not applicable to the present invention. 1) The optimum reaction temperature is around 140°C, and at this temperature, the expensive benzophenone that coexists with molecular oxygen during the oxidation of benzo7ene/imine will deteriorate. (2) When a continuous reaction is carried out, dissolved copper is oxidized and black copper oxide is deposited in the reaction system, adhering to the walls of the reactor and contaminating it, inhibiting the activity of the newly added catalyst. These two points are more serious drawbacks from the viewpoint of industrial continuous production, and even though the useful method of oxidation with molecular oxygen is known, it has not yet been effectively utilized.

(Object of the Invention) The object of the present invention is to provide a method for producing benzophenone azine using a trace amount of highly active catalyst.

Another object of the present invention is to provide a method for producing benzophenone azine in which there is no corrosion of the equipment and the benzophenone is less degraded due to the relatively low reaction temperature.

A further object of the present invention is to provide a method for producing benzophenone acine without reducing the activity of a newly added catalyst.

(Structure of the Invention) The present invention relates to a method for producing benzo7ethaneazine by bringing benzophenone imine into contact with molecular oxygen in the presence of copper, a compound having a pyridine skeleton, and a complex compound with formic acid.

With conventional simply dissolved copper, the copper is easily oxidized by blowing molecular oxygen and the activity decreases over time, and even lowers the activity of the newly added catalyst, whereas the compound with a pyridine skeleton of the present invention Copper complexes having formic acid and formic acid as ligands are extremely stable against oxidation by oxygen and can maintain high activity. This is thought to be because the complex of the present invention maintains copper in an active state due to the lone pair of aromatic nitrogen atoms of the pyridine ligand, which has characteristics not found in simple dissolved copper. .

The benzophenone imine used in the present invention is a benzophenone-containing solution prepared by iminizing benzophenone by a known method, a benzophenone imine isolated from the solution, or benzene, toluene, etc. for the purpose of smooth reaction. , xylene, hexane, propatool, butanol, dioxane, tetrahydro7rane, methylene chloride, chloroform, carbon tetrachloride, dimethylformamide, and other solvents may be added.

In the present invention, as a compound having a pyridine skeleton used as a component of the catalyst, pyridine, picoline, lutidine, collidine, ``quinoline, isoquinoline, etc. are used, but pyridine and isoquinoline are particularly preferable, and these and formic acid are coordinated. Copper complexes exist extremely stably in contact with molecular oxygen. These complexes include copper formate and pyridine or isoquinoline, or cupric chloride, diacetate.
It is obtained from copper salts such as copper and sodium formate, pyridine, or isoquinoline, and is usually synthesized and isolated in a solvent such as methanol, dioxane, toluene, etc., but it can also be used by directly incubating it in a solution containing benzophenonimine. good. The amount of these complexes used is usually 1/200 to 172,000 mol, preferably 17,400 to 1/1,600 mol, per 1 mol of benzophenone imine. The reaction temperature in the present invention may normally be 60°C or higher and lower than 180°C, but a preferred range is 80°C or higher and lower than 140°C. On the other hand, the reaction time varies depending on the amount of catalyst and the reaction temperature, but when using air as molecular oxygen, it is usually preferably in the range of 0.1 to several tens of hours, and to shorten the time, increase the oxygen partial pressure. For this purpose, molecular oxygen can be used, a contact column with molecular oxygen can be used, and a pressurized method can also be used. Furthermore, since the catalyst of the present invention is extremely stable against molecular oxygen, both batch and continuous methods are possible.

The benzophenone azine obtained in this process can be separated and purified by known methods, such as recrystallization, chromatography, etc.

(Example) The present invention will be explained in more detail by giving synthesis examples, examples, and comparative examples below.

Synthesis Example 1 8.4 g (65 mmol) of isoquinoline and 50 Il+l of methanol were added to a 1001 flask, 10 g (65 mmol) of copper formate anhydride was added thereto, and the mixture was stirred at room temperature for 1 hour. After cooling, the solid was separated, washed with methanol, and dried to obtain 17.7 g of a yellow-green solid. Elemental analysis revealed that this solid was a copper-isoquinoline-formic acid complex.

Elemental analysis values (actual values: C46, 66%, H3, 13%
, N5.01%, calculated value: C46,78%, 83.2
1%, N' 4.95%) Synthesis Example 2 16.9 g (13
1 mmol) and 50 ml of methanol were added thereto, 10 g (65 mmol) of copper formate anhydride was added thereto, and the mixture was stirred at room temperature for 1 hour. After cooling, separate the solid and wash with methanol.
Upon drying, 26.5 g of a blue solid was obtained. Elemental analysis revealed that this solid was a copper-bisisoquinoline-formic acid complex.

Synthesis Example 3 In Synthesis Example 1, 5.2 g (66 mmol) of pyridine was used instead of 8.4 g of isoquinoline to obtain 14.6 g of a green copper-pyridine-formic acid complex.

Synthesis Example 4 In Synthesis Example 2, 16.9g of isoquinoline was replaced with 10.31g of pyridine. (130 mmol) to obtain 19.2 g of a blue copper/bispirinone/formic acid complex.

Synthesis Example 5 In a 2001 flask, methanol 150J+ and second chloride
3.0 g (17.6 mmol) of copper dihydrate was added and dissolved with stirring, and then 2.4 g (35.3 mmol) of sodium formate was added and completely dissolved with stirring. After dissolving, 2.3 g (17.8 mmol) of isoquinoline was gradually added, and after stirring at room temperature for 1 hour, the precipitated solid was separated, washed with methanol, and dried to give a yellow-green copper-isoquinoline-formic acid complex. 5g was obtained.

Synthesis Example 6 In a 200ml flask, methanol 150a+1 and #2 chloride! - 3.0 g (17.6 mmol) of dihydrate was added and dissolved with stirring, and then 2.4 g (35.3 mmol) of sodium formate was added and completely dissolved with stirring. After dissolving, 4.6 g (35.6 mmol) of inquinoline was gradually added, and after stirring at room temperature for 1 hour, the precipitated solid was separated, washed with methanol, and dried, resulting in a blue copper-bisisoquinoline-formic acid complex 7. Obtained Og.

Example 1 30 g of benzophenone containing 23.7% by weight of benzo7e/imine (benzophenone imine 7, Ig.

39.2 mmol) was charged into a reactor and the temperature was raised to 100°C. To this was added 25 mg of the complex obtained in Synthesis Example 1 as a catalyst (
To 1 mole of 0,088 mm benzene imine was added 1.7440 mole of the sulfur complex, and the mixture was stirred and heated under normal pressure for 3 hours while blowing oxygen gas at 100 ml/n+in from the gas inlet tube. When the reaction solution was analyzed by chromatography, the yield of benzophenone acine was 6.
It was 7%.

Comparative Example 1 In Example 1, copper formate [Cu(HCO2)2.411□, 0125 g (0,1
1 mmol, 1 mole of benzophenonimine to 1 copper
The yield of benzophenone acine was 10% when the reaction was stalled under the same conditions except that 1/3!50 mol) was used.

Example 2 In Example 1, the heating temperature was 120°C and the heating time was 2.
When the reaction was carried out under the same conditions except for 5 hours, the yield of benzophenone azine was 95%.

Comparative Example 2 In Example 2, copper formate [Cu(HCO2)z''4820125g (0,1,
1 mmol, 1 mole of benzophenonimine to 1 copper
The yield of benzophenone azine was 42% when the reaction was carried out under the same conditions except that 7350 mol) was used.

Example 3 In Example 1, 27 mg of the complex of Synthesis Example 2 (
The yield of benzophenone azine was 94.
%Met.

Example 4 In Example 3, the heating temperature was 120°C and the heating time was 2.
When the reaction was carried out under the same conditions except that the reaction time was changed to 5 hours, the yield of benzophenone azine was 96%.

Example 5 In Example 2, 16 mg of the complex of Synthesis Example 3 (
The yield of benzophenone azine was 95.
%Met.

Example 6 In Example 2, 20 mg of the complex of Synthesis Example 4 (
The yield of benzophenone azine was 96.
%Met.

Example 7 Complex 25n+g of Synthesis Example 5 as a catalyst in Example 2
(0,088 mmol, 17440 mol of complex per 1 mol of benzophenonimine) was used, but the reaction was carried out under the same conditions, and the yield of benzophenone azine was 96.
%Met.

Example 8 In Example 3, 27 mg of the complex of Synthesis Example 6 (
The yield of benzophenone azine was 96% when the reaction was carried out under the same conditions except that 0,066 mmol and 17,610 mol of the complex was used per 1 mol of benzophenone imine).
Met.

Example 9 Benzo7ene/ene 30. containing 23.7% by weight of benzophenone imine. (39.2 mmol of benzocene/imine)
was charged into a reactor and heated to 120°C. After adding 25 mg of the complex obtained in Synthesis Example 1 (0,088 mmol, 17440 mol per 1 mol of benzophenone imine) and starting blowing oxygen from the gas introduction tube at a rate of 100 ml/min, add benzophenone liquid with the same mixing ratio every hour. and catalyst were added in 10 g units for 11 hours, and after 13 hours, the total amount was brought to 150 g, and the yield of benzophenone acine was 91%.

Example 10 In Example 9, the reaction was carried out under the same conditions except that the complex obtained in Synthesis Example 3 was used as a catalyst, and the yield of benzophenone azine was 90%.

Comparative Example 3 In Example 9, 25 mg of copper formate (0,11
mmol, 1735 per mole of benzophenonimine
The yield of benzophenone azine was 45% when the reaction was carried out under the same conditions except that 6 mol) was used.

(that's all) Patent applicant Otsuka Chemical Co., Ltd. Representative Patent Attorney 1) Iwao Mura Procedural amendment 0. picture.

1. Display of the case 1982 Patent Application No. 97172 2 Name of the invention Process for producing benzophenone azine 3 Person making the amendment Relationship to the case Patent applicant Otsuka Chemical Co., Ltd. 4 Agent Address: 1 Sonezaki, Kita-ku, Osaka 530 No. 2-8 Maruville Telephone number 06 (365) 0170 (Main) Voluntary call 6. Number of inventions increased due to amendment 7. Contents of amendment subject to amendment 1. Specification page 11, line 12 "94%" I will correct the statement to "69%."

(that's all)

Claims (2)

[Claims] (1) A method for producing benzo7e7zoazine by contacting benzophenone imine with molecular oxygen in the presence of copper, a compound having a pyridine skeleton, and a complex compound with formic acid. (2) The method according to claim 1, wherein the compound having a pyridine skeleton is pyridine or isoquinoline.