Method for improving hydration reaction efficiency of cyclohexene

Abstract

The invention belongs to the field of application of cyclohexene hydration catalysts, and particularly relates to a method for improving cyclohexene hydration reaction efficiency. The method comprises the following steps: (1) weighing a catalyst, desalted water and a cosolvent, mixing, and uniformly stirring to obtain a mixed solution; (2) slowly pouring cyclohexene into the mixed solution, sealing, replacing with nitrogen, and reacting after the nitrogen is completely replaced; and after the reaction is finished, naturally cooling to room temperature, extracting by using a dichloromethane solution, and centrifuging. The method for improving the hydration reaction efficiency of cyclohexene provided by the invention can improve the conversion rate of cyclohexene and the yield of cyclohexanol, considers the feasibility of application on a device, and greatly reduces the dosage of a cosolvent, meets the actual operation condition of the device and improves the economic benefit under the condition of equal reaction efficiency compared with the prior art. The method can be widely applied to industrial production.

Description

Technical Field

[0001] The invention belongs to the application field of cyclohexene hydration catalysts, and particularly relates to a method for improving the efficiency of cyclohexene hydration reaction. Background Art

[0002] Cyclohexanol is an important raw material for production. It is also widely used in building materials, medicine and other industries. At present, there are three mainstream technologies for the preparation of cyclohexanol, namely cyclohexane oxidation, cyclohexene hydration and phenol hydrogenation. Among them, the key to the direct hydration preparation process is to control the reaction rate of water molecules and carbon cations. During the reaction of the two, protonated alcohol will be produced. At this time, under the influence of the catalyst, the reverse reaction phenomenon caused by olefin acid catalysis will occur. Under certain catalytic conditions, it is necessary to control the reaction rate so that protons can be better added to double-bonded carbon atoms, thereby producing carbon cation intermediates. It can be seen that the catalyst plays a role throughout the process of preparing cyclohexanol by direct hydration of cyclohexene, which is not only related to the reaction rate during the period, but also affects the final preparation result.

[0003] Cyclohexene hydration reaction is in an aqueous phase environment, and under the influence of factors such as low solubility of cyclohexene, the yield of cyclohexanol is not high. Therefore, in order to optimize the catalytic reaction performance, it is necessary to further study the preparation of cyclohexanol by catalytic hydration of cyclohexene. In the prior art, researchers propose to improve reaction efficiency by adding a solubility promoter, and the solubility promoter currently used is generally C1-C10 alcohol, halogenated hydrocarbon, benzoic acid, etc., and such solubility promoters can improve the conversion rate of cyclohexene to a certain extent, but the conversion rate and the yield of cyclohexanol still need to be improved. Therefore, further research and development can significantly improve the solubility promoter of cyclohexene hydration reaction and can be applied on the device has become a problem to be solved. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of low cyclohexene conversion rate and low cyclohexanol yield in the existing cyclohexene hydration reaction technology, and to provide a method for improving the efficiency of cyclohexene hydration reaction, thereby improving the reaction efficiency of cyclohexene hydration.

[0005] To achieve the above object, the present invention adopts the following technical solutions: The present invention provides a method for improving the efficiency of cyclohexene hydration reaction, comprising the following steps: (1) Weigh the catalyst, desalted water and co-solvent, mix them and stir evenly to obtain a mixed solution; (2) Slowly pour cyclohexene into the mixed solution, seal it and replace it with nitrogen. After the nitrogen is replaced, react. After the reaction is completed, cool it naturally to room temperature, extract it with dichloromethane solution, and centrifuge it.

[0006] Furthermore, in step (1), the cosolvent is composed of polyvinyl pyrrolidone, polyacrylamide and m-cresol in a mass ratio of 1:1:1.5-2.

[0007] Furthermore, in step (1), the catalyst is a solid acid catalyst.

[0008] Furthermore, the mass ratio of the cyclohexene to the co-solvent is 1:3-12:1; the mass ratio of the catalyst, desalted water and cyclohexene is 10-11:40:12-13.

[0009] Furthermore, in step (1), the stirring time is 10-20 min.

[0010] Furthermore, in step (2), the reaction is carried out under an inert atmosphere at 80-160° C. and 0.1-5 MPa for 1-6 hours.

[0011] The beneficial effects of the present invention are as follows: the method for improving the efficiency of cyclohexene hydration reaction provided by the present invention can improve the conversion rate of cyclohexene and the yield of cyclohexanol, and considering the feasibility of application on the device, compared with the prior art, under the condition of equal reaction efficiency, the amount of co-solvent is greatly reduced, the actual operation of the device is met, the economic benefit is improved, and the method can be widely used in industrial production. DETAILED DESCRIPTION

[0012] The specific implementation of the present invention is described in detail below. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0013] In one aspect, the present invention provides a co-solvent for hydration of cyclohexene, the co-solvent comprising polyvinyl pyrrolidone, polyacrylamide and m-cresol.

[0014] In the present invention, polyvinyl pyrrolidone, polyacrylamide and m-cresol can all be obtained commercially.

[0015] On the other hand, the present invention provides a method for improving the efficiency of cyclohexene hydration reaction, which comprises contacting cyclohexene, a catalyst, a co-solvent and water under hydration reaction conditions, wherein the co-solvent is the co-solvent described above.

[0016] According to the present invention, although cyclohexene, catalyst, co-solvent and water are contacted under hydration reaction conditions, the co-solvent is the co-solvent as described above, the purpose of the present invention can be achieved, and the conversion rate of cyclohexene and the yield of cyclohexanol can be improved. However, in a preferred case, the co-solvent, catalyst and water are first mixed and stirred uniformly, and cyclohexene is added after 10-20 minutes, so as to further improve the conversion rate of cyclohexene and the yield of cyclohexanol.

[0017] In the present invention, there is no special requirement for the dosage of cyclohexene, catalyst and water, and the conventional dosage in the art can be adopted. The mass ratio of cyclohexene added to the co-solvent is 1:3-12:1.

[0018] In the present invention, there is no special requirement for the catalyst, and various solid acid catalysts commonly used in the art, such as HZSM-5, can be used. It is well known to those skilled in the art that HZSM-5 refers to hydrogen-type ZSM-5, in which the molar ratio of SiO2 / Al2O3 can be, for example, 20-40. The HZSM-5 can be commercially available.

[0019] In the present invention, there is no special requirement for the conditions of hydration reaction of cyclohexene, and the conditions commonly used in the art can be adopted, such as temperature of 80-160° C., pressure of 0.1-5 MPa, time of 1-6 h, and inert atmosphere, preferably nitrogen.

[0020] It should be understood by those skilled in the art that, in the present invention, the type of hydration reaction of cyclohexene can be any batch type, continuous type, reactive distillation type, etc.

[0021] The embodiments of the present invention are described in detail above; however, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0022] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0023] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

[0024] In order to enable those skilled in the art to better understand the scheme of the present invention and to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, the present invention is further described in detail below in conjunction with embodiments, but the invention is not limited thereto.

[0025] In the following examples and comparative examples: The catalyst used was HZSM-5, which was from Luxi Catalyst Co., Ltd.

[0026] Polyvinyl pyrrolidone, polyacrylamide and m-cresol were all purchased from commercial sources.

[0027] In the following examples and comparative examples, a gas chromatograph (purchased from, model) was used to analyze the components in the system, and the quantitative analysis was performed by a calibration normalization method, which can be carried out with reference to the prior art. On this basis, the conversion rate of cyclohexene, the yield and selectivity of cyclohexanol were calculated.

[0028] In the present invention, the conversion rate calculation formula of cyclohexanol is as follows: The calculation formula of cyclohexanol selectivity is as follows: The calculation formula of cyclohexanol yield is as follows: Where X is the conversion rate, S is the selectivity, Y is the yield, m is the mass of the component, and n is the amount of substance of the component. 0 and n 0 represent the mass and molar amount before the reaction, respectively.

[0029] Example 1 (1) Weigh 10.51 g of catalyst, 40 g of desalted water, and 12.8 g of cosolvent (polyvinyl pyrrolidone, polyacrylamide, and m-cresol in a mass ratio of 1:1:1.5) into a cooled Hastelloy container and stir for 15 min to mix evenly; (2) Weigh 12.8g of cyclohexene solution and slowly pour it into the container. Place the container into the autoclave and quickly seal the autoclave. Replace the solution with nitrogen three times. After the nitrogen replacement is completed, react at 130°C and 1300r / min for 2h. After reacting for 2h, cool naturally to room temperature, take out the evaluation solution, extract it with dichloromethane solution, centrifuge and take the oil phase for gas chromatography analysis.

[0030] Example 2 (1) Weigh 10.51 g of catalyst, 40 g of desalted water, and 12.8 g (polyvinyl pyrrolidone, polyacrylamide, and m-cresol in a mass ratio of 1:1:2) into a cooled Hastelloy container and stir for 15 min to mix evenly; (2) Weigh 12.8g of cyclohexene solution and slowly pour it into the container. Place the container into the autoclave and quickly seal the autoclave. Replace the solution with nitrogen three times. After the nitrogen replacement is completed, react at 130°C and 1300r / min for 2h. After reacting for 2h, cool naturally to room temperature, take out the evaluation solution, extract it with dichloromethane solution, centrifuge and take the oil phase for gas chromatography analysis.

[0031] Comparative Example 1 Weigh 10.51g of catalyst, 40g of desalted water, and 12.8g of cyclohexene solution and slowly pour them into the container, put the container into the autoclave, and quickly seal the autoclave. Replace with nitrogen three times. After the replacement of nitrogen is completed, react at 130℃ and 1300r / min for 2h. After reacting for 2h, cool naturally to room temperature, take out the evaluation liquid, extract with dichloromethane solution, centrifuge and take the oil phase for gas chromatography analysis.

[0032] Comparative Example 2 (1) Weigh 10.51 g of catalyst, 40 g of desalted water, and 12.8 g of m-cresol into a cooled Hastelloy container and stir for 15 min to mix well; (2) Weigh 12.8g of cyclohexene solution and slowly pour it into the container. Place the container into the autoclave and quickly seal the autoclave. Replace the solution with nitrogen three times. After the nitrogen replacement is completed, react at 130°C and 1300r / min for 2h. After reacting for 2h, cool naturally to room temperature, take out the evaluation solution, extract it with dichloromethane solution, centrifuge and take the oil phase for gas chromatography analysis.

[0033] Comparative Example 3 (1) Weigh 10.51 g of catalyst, 40 g of desalted water, and 12.8 g of polyvinyl pyrrolidone into a cooled Hastelloy container and stir for 15 min to mix evenly; (2) Weigh 12.8g of cyclohexene solution and slowly pour it into the container. Place the container into the autoclave and quickly seal the autoclave. Replace the solution with nitrogen three times. After the nitrogen replacement is completed, react at 130°C and 1300r / min for 2h. After reacting for 2h, cool naturally to room temperature, take out the evaluation solution, extract it with dichloromethane solution, centrifuge and take the oil phase for gas chromatography analysis.

[0034] Comparative Example 4 (1) Weigh 10.51g of catalyst, 40g of desalted water, and 12.8g of polyacrylamide into a cooled Hastelloy container and stir for 15min to mix well; (2) Weigh 12.8g of cyclohexene solution and slowly pour it into the container. Place the container into the autoclave and quickly seal the autoclave. Replace the solution with nitrogen three times. After the nitrogen replacement is completed, react at 130°C and 1300r / min for 2h. After reacting for 2h, cool naturally to room temperature, take out the evaluation solution, extract it with dichloromethane solution, centrifuge and take the oil phase for gas chromatography analysis.

[0035] Comparative Example 5 (1) Weigh 10.51 g of catalyst, 40 g of desalted water, and 12.8 g of cosolvent (polyvinyl pyrrolidone and polyacrylamide in a mass ratio of 1:1) into a cooled Hastelloy container and stir for 15 min to mix evenly; (2) Weigh 12.8g of cyclohexene solution and slowly pour it into the container. Place the container into the autoclave and quickly seal the autoclave. Replace the solution with nitrogen three times. After the nitrogen replacement is completed, react at 130°C and 1300r / min for 2h. After reacting for 2h, cool naturally to room temperature, take out the evaluation solution, extract it with dichloromethane solution, centrifuge and take the oil phase for gas chromatography analysis.

[0036] Effect verification The cyclohexene conversion rate, cyclohexanol yield and cyclohexanol selectivity of Examples 1-2 and Comparative Examples 1-4 were calculated. The results are shown in Table 1.

[0037] Table 1 As can be seen from Table 1, when cyclohexene is hydrated to prepare cyclohexanol, the cosolvent of the present invention is added in a certain proportion. Although the selectivity of cyclohexanol does not change significantly compared with no cosolvent or a single cosolvent, the conversion rate of cyclohexene and the yield of cyclohexanol can be greatly improved. Therefore, the method for improving the hydration efficiency of cyclohexene provided by the present invention improves the conversion rate of cyclohexene and the yield of cyclohexanol, greatly improves the cyclohexanol output of the device, and thus improves the economic benefits.

Claims

1. A method for improving the efficiency of cyclohexene hydration reaction, characterized in that: The following steps are involved: (1) Weigh the catalyst, desalted water and co-solvent, mix them and stir evenly to obtain a mixed solution; (2) Slowly pour cyclohexene into the mixed solution, seal it and replace it with nitrogen. After the nitrogen is replaced, react. After the reaction is completed, cool it naturally to room temperature, extract it with dichloromethane solution, and centrifuge it.

2. The method according to claim 1, characterized in that In step (1), the cosolvent is composed of polyvinyl pyrrolidone, polyacrylamide and m-cresol in a mass ratio of 1:1:1.5-2.

3. The method according to claim 1 or 2, characterized in that: In step (1), the catalyst is a solid acid catalyst.

4. The method according to any one of claims 1 to 3, characterized in that: The mass ratio of the cyclohexene to the co-solvent is 1:3-12:1; the mass ratio of the catalyst, the desalted water and the cyclohexene is 10-11:40:12-13.

5. The method according to claim 1, characterized in that In step (1), the stirring time is 10-20 min.

6. The method according to claim 1, characterized in that In step (2), the reaction is carried out under an inert atmosphere at 80-160° C. and 0.1-5 MPa for 1-6 hours.

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