JPS6141342B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention produces benzophenoneazines by oxidizing benzophenone imines with molecular oxygen in the presence of a copper salt catalyst, using benzophenones as a solvent; In the presence of oxygen gas, a specific amount of ammonia water is continuously added to precipitate copper salts,
The present invention relates to a method of adding benzophenone imines to this precipitate to form a copper imine complex, which is recovered and used as an oxidation catalyst for benzophenone imines. A process for producing benzophenone azine by oxidizing benzophenone imine with molecular oxygen in the presence of cuprous chloride is known from US Pat. No. 2,870,206. The patent describes a method for removing the used catalyst from the reaction solution, including a method in which the reaction solution is treated with aqueous ammonia at 110℃ under pressure, and a method in which the reaction solution is treated with a supersaturated solution of ammonium chloride at 110℃. It describes how to do this. According to the above method, it is certainly possible to remove copper salt 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's not a big deal. In the method of treatment with aqueous ammonia, part of the copper salt changes to copper oxide, and it is complicated to regenerate cuprous chloride from copper oxide, and the aqueous ammonia must be distilled off from the aqueous ammonia solution. Since ammonia is strongly bound to the copper salt recovered in this way and is not dissolved in benzophenone imine, a considerable amount of copper salt that cannot be reused is produced. In addition, in the method of treatment with a supersaturated solution of ammonium chloride, water still has to be distilled off, and the recovery rate is also slightly lower due to the complicated problem of separating the recovered copper salt and ammonium chloride. The problem is that the recovered copper salt remains in the benzophenone azine, and ammonium chloride causes a chlorination reaction of benzophenone imine and benzophenones to produce benzophenones chloride. . The present inventors have conducted extensive studies on a method for recovering copper salts that overcomes these drawbacks.
A method for recovering copper salts as a solid by adding a small amount of water in the presence or absence of molecular oxygen is described.
The patent application was filed as Japanese Patent Application No. 147453/1983 and Japanese Patent Application No. 53445/1982. As a result of further in-depth study, the inventors found that
When benzophenone imine is oxidized using benzophenone as a solvent to continuously produce benzophenone azine, a reaction solution in which a cupric salt is precipitated is often obtained; It was found that the particles were so small that it was extremely difficult to separate them by over-manipulating them. Moreover, even if water is added to such a reaction solution, the recovery rate of the copper salt is poor, and the copper salt becomes a sludge (separation from the organic layer is poor and the water content is high, so it adheres to the vessel wall). It was also found that the condition is easy to do. The present invention was completed as a result of various studies on how to coagulate and precipitate copper salts from a reaction solution in which such copper salts are precipitated in a form that is easy to pass through. That is, the present invention produces benzophenoneazines by oxidizing benzophenone imines with molecular oxygen in the presence of a copper salt catalyst, and the reaction solution contains 0.1 to 4 times as much ammonia as the copper salt in the presence of oxygen gas. The copper salt is coagulated and precipitated by continuously adding and contacting aqueous ammonia in an amount such that the mole of water is 0.5 to 40 times the mole of the copper salt, and the supernatant liquid is filtered and contains the coagulated and precipitated copper salt. This is a method for producing benzophenoneazines, which is characterized in that a slurry liquid is mixed with benzophenoneimines to form a copper imine complex, which is used as a benzophenoneimine oxidation catalyst. In the present invention, the amount of ammonia water added to coagulate and precipitate the copper salt is as described above, with the amount of ammonia being 0.1 to 4 times the molar ratio and the amount of water being 0.5 to 40 times the amount of the copper salt present in the system. It is. If there is a precipitated copper salt in the reaction system at the end of the oxidation, adding aqueous ammonia in the amount described above to the unprecipitated copper will yield a well-coagulated copper salt as a precipitate. Further, the concentration range of the ammonia water to be added is preferably 0.1 to 28%, particularly 5 to 20%. If a low concentration is used, the precipitate will turn into sludge,
It becomes difficult to over-operate. If a high concentration ammonia is used, the ammonia concentration will be high locally, so it will not be possible to prevent the production of copper oxide, although it may be a small amount. Further, the amount of reacted ammonia is preferably about 0.1 to 3 times the mole of the copper salt. As the operating conditions for copper salt recovery when carrying out the present invention, the addition temperature of ammonia water is 60 to 250.
℃, especially 70 to 140℃ is suitable. As a general tendency, the lower the temperature, the better the precipitation and aggregation of copper salts, and the higher the recovery rate. The form of the catalytic copper salt used in the present invention is particularly suitable as a copper halide, particularly cuprous chloride,
It can be applied to cupric chloride, copper oxychloride, cuprous bromide, cupric bromide, copper oxybromide, copper iodide, and mixtures thereof. The pressure in the present invention may be normal pressure or increased pressure without any particular problem. As a reaction condition for the imine oxidation reaction in the method of the present invention, the reaction temperature 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, 1 to 10 atm, and when air is used, about 1 to 20 atm is appropriate. The catalyst is preferably added in an amount of 1/100 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, so it is not necessarily necessary to add a solvent, but the amount of benzophenones used as a dissolving solvent for benzophenone azine produced by the reaction is , 2 to 6 times the amount of the benzophenone imine is suitable. If the amount of benzophenones is small, the concentration of benzophenone azine produced by oxidation will be high, resulting in a very high viscosity of the reaction solution and a high melting point of the reaction solution, which is extremely inconvenient for operation. will come. Furthermore, if the amount of benzophenones is large, the concentration of benzophenone imine decreases, resulting in a decrease in the oxidation rate. 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. 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 steps. According to the method of the present invention, both copper salts, cuprous salts and cupric salts, coagulate and precipitate as solids, which are quickly dissolved in benzophenone imines to form copper benzophenone imine complexes. It can be used again as a catalyst for the oxidation reaction of benzophenone imines without any problems. Example 1 400 g of raw material liquid was fed per hour into a stainless steel reactor with an upper and lower flange type and an internal volume of 1.5 (liquid composition: 1 kg of raw material liquid contained 229.5 g of benzophenone imine, 764 g of benzophenone, and 6.5 g of cuprous chloride). The liquid temperature in the reactor is maintained at 120℃. Next, pressurized air of 4 atmospheres was blown into the reactor from a ring spargeer located at the bottom of the reactor at a flow rate of 3 per minute based on the volume under normal pressure, and a continuous reaction was carried out with stirring. The average residence time of the liquid was maintained at 2 hours, and after reaching a steady state approximately 5 hours after the start of the reaction, the reaction was continued for the next 95 hours. Response rate is 95%
was almost stable. The reaction solution was first drawn out continuously into an intermediate tank by overflow, and then taken out to the outside at regular intervals. In addition, the waste gas was cooled with a cooler to recover the accompanying benzophenone, and then returned to normal pressure and released into the atmosphere. The oxidation reaction liquid extracted from the pressurized intermediate tank is stored in a heated storage tank at normal pressure. The oxidation reaction liquid was sent from the storage tank using a pump at a rate of 400 g per hour to a stirring tank with an internal volume of 0.5, and at the same time, aqueous ammonia with a concentration of 14% was supplied to the stirring tank at a rate of 5 ml per hour and mixed vigorously in the air. did. The liquid that overflowed the stirring tank was led to a static tank, and the precipitated copper salt was separated by sedimentation, and then the supernatant liquid was extracted to the outside through a Teflon cloth. In this way, the copper salt recovery operation is carried out.
This was done continuously for 95 hours. Copper salt concentration 100~
A liquid with a concentration of 200 ppm (concentration 6,500 ppm before the recovery operation) is obtained, but this liquid is further subjected to liquid-liquid extraction under pressure using 15% aqueous ammonia to reduce the copper salt concentration to 5 to 20 ppm. It was something I could do. On the other hand, a copper salt slurry solution with a concentration of 25-35% was obtained from the bottom of the static tank (recovery rate 97%).
~98.5%). This slurry liquid was mixed with the benzophenone imine liquid as it was to produce a copper imine complex, which could be used again in the oxidation reaction. The composition of the copper salt is approximately CuCl ₂・Cu(OH) ₂・
( _NH3 )m・( _H2O )n(m=0.4~1.4, n=0~
1.0). Comparative Examples 1 and 2 Using the oxidizing liquid obtained in Example 1, the oxidizing liquid was added at a rate of 400 g/hour to an internal volume of 0.5 in the same manner as in Example 1.
At the same time, aqueous ammonia with a concentration of 14% was supplied to the stirring tank at the flow rate shown in Table 1 and mixed vigorously in air. The liquid that overflowed the stirring tank was led to a static tank. The conditions and results are shown in Table 1 in comparison with Example 1. 【table】

Claims (1)

[Claims] 1. Oxidize benzophenoneimines with molecular oxygen in the presence of a copper salt catalyst to produce benzophenoneazines, and in the presence of oxygen gas, the reaction solution contains ammonia of 0.1 to 4 times the mole of copper salt and water. The copper salt is coagulated and precipitated by continuously adding and contacting aqueous ammonia in an amount of 0.5 to 40 times the mole of the copper salt, the supernatant liquid is filtered, and the slurry containing the coagulated and precipitated copper salt is subjected to benzodilation. 1. A method for producing benzophenone azines, which comprises mixing them with phenone imines to form a copper imine complex and using the complex as a benzophenone imine oxidation catalyst.