JPS6141343B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention involves producing benzophenoneazines by oxidizing benzophenone imines with molecular oxygen in the presence of a copper salt catalyst, and then adding a small amount of salt-containing aqueous solution to the reaction system to precipitate the copper salt. and how to recover it. benzophenonimine in the presence of cuprous chloride,
A method for preparing benzophenoneazines by oxidation with molecular oxygen is known from US Pat. No. 2,870,206. The patent also describes a method for removing the used catalyst from the reaction solution by subjecting the reaction solution to pressure.
A method of treating with aqueous ammonia at 110°C and a method of treating the reaction solution and a supersaturated solution of ammonium chloride at 110°C are described. According to the above method, copper salt can certainly be removed from the reaction solution, but the copper salt recovered in this way is an aqueous solution of copper/ammine complex, and it is easy to regenerate and use the copper salt catalyst from there. It doesn't matter. Furthermore, if a copper salt remains in the benzophenone azine, there is a risk that copper will be mixed into the hydrazine or that the hydrazine will be decomposed when it is hydrolyzed to obtain hydrazine. Therefore, after the reaction is complete, the copper salt needs to be removed from the reaction system and recovered in a form that can be easily reused. For this purpose, JP-A-53-71045 discloses a method for precipitating and recovering copper salts from a reaction system by adding reaction product water or water. However, in this method of precipitation of copper salts using water alone, the precipitation rate of copper salts is still insufficient, and copper salts often precipitate in the form of fine particles, which cannot be recovered by means such as filtration or sedimentation separation. There were some drawbacks that were difficult to overcome. The present invention is a method for recovering copper salt in a form that can be easily reused in a high yield and by a simple means, and is particularly effective in continuous production methods where fine particles of copper salt tend to precipitate. It is something. That is, the present invention produces benzophenoneazines by oxidizing benzophenone imines with molecular oxygen in the presence of a cuprous chloride catalyst, and adds lithium chloride, potassium chloride, sodium chloride, and calcium chloride to the reaction solution. , ammonium chloride, potassium bromide,
Adding an aqueous solution of a salt selected from sodium bromide, calcium bromide, or ammonium bromide in an amount such that the salt is 0.1 to 2 times the mole of cuprous chloride and the water is 0.5 to 40 times the mole of cuprous chloride. This is a method for producing benzophenone azines, which is characterized by precipitating a copper salt by contacting the benzophenoneazines. The amount of salts in the aqueous solution of salts used in the present invention is 0.1 to 2 times the mole of cuprous chloride, and the amount of water is 0.5 to 40 times the mole of cuprous chloride. If salts and water are added in amounts greater than the above ranges, the amount of soluble copper salts will increase, and problems such as recovery and reuse of precipitated copper salts and wastewater treatment may occur, which is not preferable. Moreover, if a smaller amount than the above range is added, the effect of salt addition will not be produced, resulting in a low recovery rate of copper salt. The operating temperature for recovery of the copper salt of the present invention is preferably in the range from room temperature to 300°C, particularly from room temperature to 230°C.
The pressure may be normal pressure or increased pressure, and furthermore, it can be operated in the presence or absence of oxygen gas. Further, the operation can be suitably carried out using a common industrial extraction device. For example, spray tower, perforated plate tower,
A mixer-settler, a rotating disk column, a pulsating extraction column, a centrifugal extractor, etc. can be used alone or in combination, and a combination of a mixer-settler or a mixer and a filtration device is particularly suitable. The operation time is not particularly limited, but 0.1 to 10 hours is sufficient. The reaction temperature for the imine oxidation reaction in the method of the present invention is 60 to 250°C, but especially 70°C.
~230°C is preferred. The pressure is not particularly limited, whether normal pressure or pressurization, but when pure oxygen is used as the oxygen-containing gas, it is appropriate to be 1 to 10 atmospheres, and when air is used, it is approximately 1 to 20 atmospheres. The catalyst used in the present invention is cuprous chloride. This catalyst is preferably added in an amount of 0.01 to 1 mol per 1 mol of the raw material imine compound. In the oxidation reaction and copper salt recovery method of the present invention, unreacted benzophenones act as a solvent;
Although it is not always necessary to add a solvent, it is possible to add a solvent to help dissolve the benzophenone azine produced by the reaction and to maintain the reaction system in a solution state. The solvent used in the present invention may be any solvent that is resistant to oxidation in the imine oxidation reaction and helps dissolve the azine product, such as hydrocarbons: hexane, heptane, decane, cyclohexane, cyclooctane, methyl Cyclohexane, benzene, toluene, xylene, pseudocumene, mesitylene, halides: ethylene dichloride, tetrachloroethylene, chlorobenzene, dichlorobenzene, nitro compounds: nitrobenzene, ether compounds: diisopropyl ether, dipropyl ether, anisole, diphenyl ether, Tetrahydrofuran, ester compounds: butyl acetate, methyl benzoate, phenyl benzoate, dimethyl adipate, dimethyl phthalate,
Examples include dioctyl phthalate, nitrile compounds: benzonitrile, ketone compounds: diisobutyl ketone, acetophenone, aminated compounds: pyridine, ethylenediamine, butylamine, aniline, and other compounds: dimethylformamide, dimethyl sulfoxide. The benzophenoneimines used as raw materials in the reaction of the present invention are compounds represented by the following general formula. (However, in the above formula, R ₁ and R ₂ represent hydrogen, halogen, alkyl, alkoxy, or nitro group. R ₁ and R ₂ may be the same or different. Also, m and n are 1 to 5 ) In particular, in addition to benzophenoneimine, 2-methyl,
3-methyl, 4-methyl, 4-chloro, 4-nitro, 4-methoxybenzophenonimine are preferably used. In addition, the target reaction is to simultaneously add ammonia and oxygen-containing gas to benzophenones and react.
Also included within the scope of the present invention is a method for producing benzophenoneazines in one step. According to the invention, the catalyst precipitates as a solid together with the added salts. Moreover, even when coagulation and precipitation are extremely difficult with water alone, the copper salt obtained as a solid has excellent cohesive properties and particle size, so it can be easily separated from the reaction system. Furthermore, the separated solid copper salt quickly dissolves in benzophenone imine to form a copper benzophenone imine complex, and can be used as a catalyst without any problem even if it is reused in the oxidation reaction. It is something. Example 1 350 g of a solution with a benzophenone imine content of 25% and the remaining total amount being benzophenone and cuprous chloride
3.08 g was charged into a reactor and heated to 120°C, and then stirred for 1.5 hours while blowing oxygen at a flow rate of 350 ml/min from the blow port at the bottom of the reactor. During this time, the exhaust gas was continuously extracted and the produced water was condensed through the condenser. After 1.5 hours, the reaction rate of benzophenoneimine was 97.8%. Collect 90g of this reaction solution and put it into another reactor, keep the temperature at 100℃, add 1.25ml of 20% sodium chloride aqueous solution, mix vigorously for 20 minutes, and keep the temperature at 100℃. When the mixture was left standing for 1 hour, it was separated into a precipitated layer of copper salt and sodium chloride and a liquid layer. The concentration of copper present in the liquid layer was determined colorimetrically using the bank proin method and was found to be 182 ppm. Therefore, the precipitation rate after standing for 1 hour, which means the production rate of precipitated copper salt that is extremely easy to recover, was 96.8%. Furthermore, the liquid layer was passed through a glass filter with a pore size of 5 to 10 μm, and the copper concentration present in the liquid was similarly determined to be 163 ppm. Therefore, the copper precipitation rate was 97.1%, and only 0.3% of the precipitated copper salts were difficult to recover. Using the copper salt thus recovered by precipitation in place of cuprous chloride, oxidation of benzophenone imine and copper salt precipitation experiments were carried out under the same conditions as in the case of cuprous chloride. However, almost the same results as in the case of cuprous chloride were obtained. The amount of precipitated copper salts that are difficult to recover was calculated using the following formula. (Sedimentation rate/precipitation rate after standing for 1-1 hours) x 100 (%
) Comparative Example 1 Using 90 g of the reaction solution obtained in Example 1, a copper salt was precipitated under exactly the same conditions as in Example 1, except that 1.00 ml of water was used instead of the 20% aqueous sodium chloride solution. Then, when the mixture was allowed to stand at 100° C. for 1 hour, it was separated into a copper salt precipitate layer and a liquid layer. The concentration of copper present in the liquid layer was determined colorimetrically using the bathocuproine method.
It was 380ppm. Furthermore, the liquid layer was filtered through a glass filter with filter size G-4, and the copper concentration present in the liquid was determined in the same manner.
It was 250ppm. Therefore, the copper precipitation rate is 95.6%, 1
The precipitation rate after standing for a period of time was 93.3%, and 2.4% of the precipitated copper salts were difficult to recover. Example 2 Using 90g of the reaction solution obtained in Example 1, 20%
The copper salt was precipitated under the same conditions as in Example 1, except that 1.25 ml of a 20% ammonium chloride aqueous solution was used instead of the sodium chloride aqueous solution, with stirring, mixing, and standing. After standing still for 1 hour, it was separated into a precipitated layer of copper salt and ammonium chloride and a liquid layer. The copper concentration in the liquid layer was determined colorimetrically using the bathocuproin method and was found to be 250 ppm. Furthermore, the liquid layer was passed through a glass filter, and the copper concentration present in the liquid was determined in the same manner.
It was 220ppm. Therefore, the precipitation rate of copper was 96.1%, and the precipitation rate after standing for 1 hour was 95.6%, and 0.5% of the precipitated copper salts was difficult to recover. Example 3 A titanium autoclave with an internal volume of 2 and a top and bottom flange type equipped with a thermocouple sheath tube, a ring spargeer for gas injection, a gas outlet, an imine solution supply port, an overflow tube for the reaction solution, a pressure gauge, and an electromagnetic stirrer. 900g of raw material liquid was charged into the tank. The raw material solution was prepared by dissolving cuprous chloride in an amount of 1/20 mole based on benzophenone imine in a solution containing 24% benzophenone imine, with the remaining total amount being benzophenone. Next, the liquid temperature is adjusted to maintain a temperature of 120℃ using electric heat from the outside. While stirring, maintain the pressure in the system at 4 atmospheres and pump air at 7/min (volume under normal pressure;
The reaction was carried out in batches for 2 hours. After the batch reaction was completed, a plunger pump was used to start supplying the raw material liquid at a rate of 450 g/hour, and the reaction was continued for 700 hours under the same conditions with air at 7/min (NTP). . The reaction solution was continuously extracted through an overflow tube.
The average residence time of the liquid was 2 hours, and the reaction rate of benzophenone imine was over 95%. 100 g of the extracted reaction solution was collected and charged into a 300 ml four-necked reaction flask equipped with a condenser, thermometer, and stirrer. After adjusting the liquid temperature to maintain it at 100°C, 1.25 ml of 20% aqueous sodium chloride solution was added and mixed with vigorous stirring for 20 minutes. Then 100℃
When the mixture was allowed to stand for 1 hour, it was separated into a precipitated layer of copper salt and sodium chloride and a liquid layer. Colorimetric determination of copper concentration in the liquid layer using the bathocuproine method
It was 232ppm. Furthermore, the liquid layer was passed through a glass filter, and the copper concentration present in the liquid was similarly determined and found to be 67 ppm. Therefore, the precipitation rate of copper is 98.4%, and the precipitation rate after standing for 1 hour is
94.5%, and 4.0% of the precipitated copper salt was difficult to recover. Comparative Example 2 and Examples 4, 5, 6 Using the reaction liquid extracted in the continuous operation of Example 3, an ammonium chloride aqueous solution with the concentration shown in Table 1 was added instead of the 20% sodium chloride aqueous solution.
The copper salt was precipitated by stirring and mixing under the same conditions as in Example 3 except that 1.25 ml was used. then
When the mixture was allowed to stand at 100° C. for 1 hour, it was separated into a precipitated layer of copper salt or copper salt and ammonium chloride and a liquid layer. The copper concentration in the liquid layer was determined colorimetrically by the bathocuproine method, and the liquid layer was further passed through a glass filter and the copper concentration was determined in the same manner. These results are shown in Table 1. From Table 1, the precipitation rate of copper salts is the same in Comparative Example 2 and Examples 4, 5, and 6, but there is a large difference in the amount of copper salts present as microparticles that are extremely difficult to recover. I understand that.

【table】

[Table] Comparative Examples 3-4 1.25ml of 20% ammonium chloride aqueous solution of Example 5
The procedure was the same as in Example 5 except that the amount of the solution used was changed instead of . The results are shown in Example 5.
A comparison is shown in Table 2.

【table】

Claims (1)

[Claims] 1. Oxidize benzophenoneimines with molecular oxygen in the presence of a cuprous chloride catalyst to produce benzophenoneazines, and add lithium chloride, potassium chloride, sodium chloride, calcium chloride, ammonium chloride, and odor to the reaction solution. Add an aqueous solution of a salt selected from potassium chloride, sodium bromide, calcium bromide or ammonium bromide to a concentration of 0.1 cuprous chloride.
A method for producing benzophenoneazines, characterized by precipitating a copper salt by adding and contacting water in an amount of 0.5 to 40 times the mole of cuprous chloride.