Preparation method of cyclohexene oxide

Abstract

The invention provides a preparation method of cyclohexene oxide, and belongs to the field of organic synthesis. The method comprises the following steps: adding cyclohexene and a catalyst into a solvent in the presence of a trimetal six-membered porphyrin catalyst, dropwise adding an oxidant peracetic acid solution into the system, starting a reaction, and dropwise adding a sodium hydroxide solution at the same time; and after the reaction is finished, standing, washing with water, separating liquid, and distilling an oil phase to obtain cyclohexene oxide. Wherein three metal ions in the three-metal six-element porphyrin catalyst are manganese ions, iron ions and cobalt ions. The application of the three-metal six-element porphyrin catalyst is beneficial to reduction of use and emission of harmful chemical substances, and efficient catalytic reaction can be realized under milder conditions. The trimetal six-membered porphyrin catalyst can be recycled and reused after reaction, and still keeps good activity and selectivity after multiple cycles.

Description

Technical Field

[0001] The invention belongs to the field of organic synthesis, and in particular relates to a method for preparing cyclohexene oxide. Background Art

[0002] 1.2-Epoxycyclohexane, molecular formula C6H 10 O, molecular weight 98.143, boiling point 129-132℃, CAS number: 286-20-4. It is a colorless or light yellow liquid with fragrance, the main raw material of pesticide acaricide, as well as surfactant and rubber additive.

[0003] There are many methods for synthesizing cyclohexene oxide, which are basically based on the oxidation of cyclohexene as raw material. According to the different oxygen sources, it can be divided into the following types:

[0004] CN114456127A reports a method for synthesizing cyclohexene oxide using a heterogeneous single-atom catalyst as a catalyst, cyclohexene as a preparation raw material, and molecular oxygen as an oxygen source. The reaction yield is low and the purification is relatively complicated.

[0005] CN113908828A reports a method in which bismuth molybdate is used as a catalyst, cyclohexene is used as a substrate, acetonitrile is used as a reaction solvent, and hydrogen peroxide solution is used as an oxidant. The conversion rate of cyclohexene can reach 77.0%, and the selectivity of cyclohexene oxide can reach 83.6%. The yield of this method is medium, and the preparation of the catalyst is relatively complicated.

[0006] Sinopec reported in CN110498778B that cyclohexene is used as substrate, acetonitrile is used as reaction solvent, tert-butyl hydroperoxide solution is used as oxidant, and olefin epoxidation reaction is carried out on a thin layer Ti-MWW molecular sieve catalyst with a high skeleton titanium content and a sheet thickness of not more than 20nm and a skeleton titanium molar content of not less than 2%. After the reaction, the reaction liquid is distilled and a fraction of 130-135°C is taken to obtain cyclohexene oxide. The reaction has a high conversion rate, but the production cost is relatively high.

[0007] Shanghai University of Technology reported in CN116813570A that cyclohexene is used as raw material, an organic solvent is added in the presence of an oxygen enhancer, and then a modified titanium dioxide catalyst is added, light is irradiated and oxygen is passed through during the reaction, and the reaction is heated and stirred to obtain epoxycyclohexane. This method is green and mild, but the reaction time is too long.

[0008] China Tianchen Engineering Co., Ltd. reported in CN113461641A that a catalyst product and cyclohexene are added to a reactor, heated and kept warm, a cumene hydroperoxide solution is added, heated and stirred until the reaction is complete, filtered, washed with water, and allowed to stand to separate to obtain cyclohexene oxide. The reaction conditions are mild, but the process is complicated.

[0009] The inventors have found a method through long-term experiments and explorations, in which cyclohexene and a catalyst are added to a solvent under certain temperature conditions, an oxidant peracetic acid solution is dripped into the above system, the reaction is started, and a sodium hydroxide solution is dripped at the same time. After the reaction is completed, the mixture is allowed to stand, washed with water, and separated, and the oil phase is subjected to negative pressure distillation, and the fraction at -0.08MPa and 55°C is collected, which is cyclohexene oxide. Summary of the invention

[0010] The object of the present invention is to provide a method for preparing cyclohexene oxide with low raw material cost, few by-products and high yield.

[0011] To achieve the purpose of the invention, the technical scheme adopted by the present invention is: a method for preparing cyclohexene oxide, in the presence of a trimetallic hexaporphyrin catalyst, cyclohexene and the catalyst are added to a solvent, an oxidant peracetic acid solution is dripped into the above system, the reaction is started, and a sodium hydroxide solution is dripped at the same time. After the reaction is completed, the mixture is allowed to stand, washed with water, and separated, and the oil phase is distilled to obtain cyclohexene oxide.

[0012] The synthetic route of the method of the present invention is:

[0013]

[0014] Specifically, cyclohexene and a catalyst are added to a solvent at 0°C to 40°C, and an oxidant peracetic acid solution is dripped into the above system to start the reaction, and a sodium hydroxide solution is dripped at the same time. After the reaction is completed, the mixture is allowed to stand, washed with water, and separated, and the oil phase is distilled to obtain cyclohexene oxide.

[0015] The reaction rate is controllable in this temperature range and will not react too quickly, resulting in an increase in side reactions. While ensuring the stability of the reaction system, at this temperature, the double bond of cyclohexene is more easily attacked by the oxidant to form an epoxy compound.

[0016] Specifically, the solvent is dichloromethane or dichloroethane, which has a high boiling point and can be recycled and reused in subsequent processes.

[0017] Specifically, the catalyst is a trimetallic hexaporphyrin, and the trimetallic ions are manganese ions, iron ions, and cobalt ions, which provide the catalytic activity of the porphyrin and show a high degree of selectivity, thereby accelerating the oxidation process of cyclohexene.

[0018] The trimetallic hexaporphyrin catalyst is a porphyrin derivative with 14-π electron conjugation, which is composed of three pyrrole rings connected by a methine bridge. The special feature of this catalyst is its metal ion coordination mode. The metal ion is not located inside the plane of the porphyrin macrocyclic ring, but above it, forming an octahedral coordination configuration with three pyrrole nitrogen atoms and three other ligands, and the whole molecule presents a bowl-shaped configuration.

[0019] By introducing manganese, iron, and cobalt metal ions, the structure and properties of porphyrin catalysts can be regulated to selectively accelerate the catalytic process.

[0020] Specifically, the mass ratio of cyclohexene, solvent, peracetic acid and catalyst is 1:1-5:0.8-1.5:0.05-0.3.

[0021] Specifically, the peracetic acid solution is added dropwise for 3 h to 4 h.

[0022] Specifically, before the oil phase is subjected to vacuum distillation, atmospheric distillation is first performed, and then the temperature is lowered and vacuum distillation is performed after the solvent is recovered. Atmospheric distillation is first performed to remove by-products including cyclohexanone and cyclohexanol.

[0023] Specifically, the concentration of peracetic acid used is 12% to 30%.

[0024] Compared with the prior art, the method for preparing cyclohexene oxide of the present invention has the following beneficial effects:

[0025] 1. High efficiency of the catalyst. The trimetallic hexaporphyrin has a special coordination configuration, where the metal ion is located above the plane of the porphyrin macrocyclic ring. This structure increases the probability of the active center contacting the reaction substrate, and the trimetallic hexaporphyrin achieves this process by decomposing the metal porphyrin through the interaction between the metal porphyrin and oxygen to form an OO bond.

[0026] 2. Environmental protection and economy: the application of trimetallic hexaporphyrin catalysts helps reduce the use and emission of harmful chemicals because they can achieve efficient catalytic reactions under milder conditions. Trimetallic hexaporphyrin catalysts can be recovered and reused after the reaction, and they still maintain good activity and selectivity after multiple cycles. DETAILED DESCRIPTION

[0027] The present invention is further described below in conjunction with specific embodiments, but the present invention is not limited to these embodiments. Those skilled in the art should recognize that the present invention covers all possible alternatives, improvements and equivalents within the scope of the claims.

[0028] Embodiment 1:

[0029] A) Add 1mmol tetraphenylporphyrin (TPPH2) and 80ml N,N-dimethylformamide (DMF) to a 250ml three-necked flask and heat to reflux at 130℃. Add ferrous sulfate heptahydrate (FeSO4•7H2O) with a molar ratio of 1.3:1 to TPPH2 from the top of the condenser three times within 15min, and continue to reflux for about 8~12h. After stopping the reaction, add about 150mL of water while hot, stir for 10min, let it stand and cool to room temperature, filter, rinse with appropriate organic solvent and water, and vacuum dry the filter cake to obtain tetraphenylporphyrin iron. Tetraphenylporphyrin cobalt and tetraphenylporphyrin manganese are prepared in the same way with a ratio of 2:1:1.

[0030] B) Add 300.0g cyclohexene, 600.0g dichloromethane and 48.0g catalyst β to a 5000ml three-necked flask; first control the temperature at 12°C. Weigh 1650.0g 20% ​​peracetic acid and 880.0g 20% ​​sodium hydroxide, and pass the peracetic acid solution from below the liquid surface under stirring, and drip the sodium hydroxide solution from above the liquid surface. The flow rate of the former is 3 times that of the latter. During the dripping process, the temperature is controlled at 25°C. The dripping is completed after about 3.4h. After the dripping is completed, keep the temperature at 30°C for 0.5 hours. After the insulation is completed, the reaction solution is allowed to stand and separate, and the organic phase is taken out and washed three times with 2000.0g soft water in a separating funnel. The oil phase is passed into a distillation tower for negative pressure distillation, and collected at -0.08MPa. The fraction at 55°C is epoxycyclohexane. 332.43 g of cyclohexene oxide was obtained with a purity of 99.12% and a yield of 92.03%.

[0031] Embodiment 2:

[0032] On the basis of Example 1, the reaction temperature was changed to 30°C, and the other reaction conditions were the same as those in Example 1. The reaction results are shown in Table 1.

[0033] Embodiment 3:

[0034] On the basis of Example 1, the reaction temperature was changed to 20°C, and the other reaction conditions were the same as those in Example 1. The reaction results are shown in Table 1

[0035] Embodiment 4:

[0036] On the basis of Example 1, cyclohexene 300.0 g, 20% peracetic acid 1500.0 g, 20% sodium hydroxide 800.0 g were used. The other reaction conditions were the same as those in Example 1. The reaction results are shown in Table 1.

[0037] Embodiment 5:

[0038] On the basis of Example 1, the reaction conditions were changed to 300.0 g of cyclohexene, 1450.0 g of 20% peracetic acid, and 770.0 g of 20% sodium hydroxide. The other reaction conditions were the same as those in Example 1. The reaction results are shown in Table 1.

[0039] Embodiment 6:

[0040] On the basis of Example 1, the reaction conditions were changed to 300.0 g of cyclohexene, 1390.0 g of 20% peracetic acid, and 730.0 g of 20% sodium hydroxide. The other reaction conditions were the same as those in Example 1. The reaction results are shown in Table 1.

[0041] Embodiment 7:

[0042] On the basis of Example 1, the solvent was changed to dichloroethane, and the other reaction conditions were the same as those in Example 1. The reaction results are shown in Table 1.

[0043] .

[0044] In addition to the above embodiments, the present invention may also have other implementation modes. Any technical solution formed by equivalent replacement or equivalent transformation falls within the protection scope required by the present invention.

Claims

1. A method for preparing cyclohexene oxide, characterized in that: At 0°C to 40°C, cyclohexene and a catalyst are added to a solvent, and an oxidant peracetic acid solution is dripped into the above system to start the reaction, and a sodium hydroxide solution is dripped at the same time; after the reaction is completed, the mixture is allowed to stand, washed with water, and separated, and the oil phase is distilled to obtain cyclohexene oxide.

2. The method for preparing cyclohexene oxide according to claim 1, wherein: The solvent is dichloromethane or dichloroethane.

3. The method for preparing cyclohexene oxide according to claim 1, wherein: The catalyst is a trimetallic hexaporphyrin, and the trimetallic ions are manganese ions, iron ions and cobalt ions.

4. The method for preparing cyclohexene oxide according to claim 1, wherein: The mass ratio of cyclohexene, solvent, peracetic acid and catalyst is 1:1-5:0.8-1.5:0.05-0.

3.

5. The method for preparing cyclohexene oxide according to claim 1, wherein: The addition time of peracetic acid solution is 3h-4h.

6. The method for preparing cyclohexene oxide according to claim 5, wherein: The mass concentration of peracetic acid used is 12% to 30%.

7. The method for preparing cyclohexene oxide according to claim 1, wherein: Before the oil phase is distilled under reduced pressure, it is first distilled under normal pressure, and then the temperature is lowered and distilled under reduced pressure after the solvent is recovered.

Images