Preparation method of cyclohexanone oxime
By using heterogeneous amoximetization reaction process and titanium silicon molecular sieve catalyst in the production of cyclohexanone oxime, combined with inert organic solvents and separation technology, the problems of long process flow and high energy consumption are solved, and cyclohexanone is realized Efficient preparation and process optimization of oxime.
Patent Information
- Application Number
- CN202411540911.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-31
- Publication Date
- 2025-02-11
AI Technical Summary
The existing cyclohexanone oxime production process is lengthy, with many equipment and high energy consumption, resulting in poor environmental and economic benefits.
The heterogeneous amoxiximetization reaction process is used, and the reaction is carried out with the participation of an inert organic solvent by using a titanium silicon molecular sieve as a catalyst, and then the high-purity cyclohexanone oxime is separated by decanting, distillation or distillation.
The preparation process of cyclohexanone oxime is shortened, and the tert-butanol recovery, toluene extraction and toluene distillation are reduced, which saves equipment investment and reduces energy consumption.
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of chemical industry, and in particular to a method for preparing cyclohexanone oxime. Background Art
[0002] Cyclohexanone oxime, molecular formula: C6H 11 NO is an important organic chemical product. Under normal conditions, cyclohexanone oxime is a white crystal with a pungent odor, a melting point of 90°C, a boiling point of 206°C, and a molecular weight of 113.16. Cyclohexanone oxime is insoluble in water, and its solubility in water at room temperature is less than 0.1g. Cyclohexanone oxime is mainly used in industry to produce caprolactam through a liquid-phase Beckmann rearrangement reaction, and caprolactam is a monomer of nylon-6 fiber. Over the years, nylon-6 fiber has a wide range of application scenarios. Up to now, the most widely used cyclohexanone oxime production process in industry is the cyclohexanone ammoximation process, which accounts for more than 90wt% of the total production capacity. The traditional ammoximation process reaction conditions are mostly tert-butyl alcohol as solvent, titanium silicon molecular sieve as catalyst, and homogeneous reaction under the same reaction raw materials, which leads to the subsequent cyclohexanone oxime refining process, involving a long solvent recovery and ammoxime water extraction and extraction agent recovery process. It can be seen that the process is relatively lengthy, involves more equipment, has higher energy consumption and costs, and has poor environmental and economic benefits. Summary of the invention
[0003] In view of this, the object of the present invention is to provide a method for preparing cyclohexanone oxime. The technical problem to be solved is how to prepare cyclohexanone oxime in a heterogeneous environment and select a suitable inert solvent to separate cyclohexanone oxime, so as to shorten the cyclohexanone oxime preparation process and reduce the tert-butyl alcohol recovery, toluene extraction and toluene distillation stages.
[0004] In order to achieve the above object, the present invention provides a method for preparing cyclohexanone oxime, comprising the following steps:
[0005] 1) Generation of cyclohexanone oxime: hydrogen peroxide and gaseous ammonia are mixed in a feed mixer and then enter a reaction mixer; cyclohexanone and an inert organic solvent are mixed in another feed mixer and then enter the reaction mixer, and a crude product containing cyclohexanone oxime is obtained through a heterogeneous ammoximation reaction;
[0006] 2) Purification of cyclohexanone oxime: The crude product containing cyclohexanone oxime obtained in step 1) is separated into an oil phase and a water phase containing a catalyst by decantation.
[0007] 3) The oil phase obtained in step 2) is separated into the inert solvent and the pure cyclohexanone oxime by distillation or rectification according to the different boiling points of the selected inert solvent.
[0008] Preferably, in step 1), the concentration of the hydrogen peroxide is 25-35 wt %.
[0009] Preferably, in step 1), the reaction temperature of the heterogeneous ammoximation reaction is 50-100°C, more preferably 75-90°C.
[0010] Preferably, in step 1), the pressure of the heterogeneous ammoximation reaction is 0.1 MPa·G to 0.8 MPa·G, and more preferably 0.3 MPa·G to 0.5 MPa·G.
[0011] Preferably, in step 1), the inert organic solvent is selected from one or a mixture of two of n-hexane, isoheptane, cycloheptane, n-heptane, isobutanol, cyclohexane and xylene; more preferably, it is one of n-hexane, cyclohexane, isoheptane and xylene.
[0012] Preferably, in step 1), the mass ratio of the inert organic solvent to cyclohexanone is 1 to 10:1, more preferably 4 to 6:1.
[0013] Preferably, in step 1), the catalyst for the heterogeneous ammoximation reaction is titanium silicon molecular sieve, and its content is 2-10wt%, more preferably 3-6%.
[0014] Preferably, step 2) further comprises the step of separating cyclohexanone oxime and the inert organic solvent by distillation or rectification after the decantation separation.
[0015] The present invention is beneficial in that:
[0016] The preparation method of cyclohexanone oxime of the present invention uses titanium silicon molecular sieve (TS-1) as a catalyst, cyclohexanone, hydrogen peroxide and gaseous ammonia in the traditional method as raw materials, and in the presence of an inert organic solvent, in a heterogeneous ammonia oximation reactor, under a certain pressure, a certain temperature and a certain average residence time to complete an ammonia oximation reaction with a high conversion rate / selectivity; while completing the reaction, a preliminary oil-water separation is also completed; and then a simple decantation separation and distillation or rectification method is used to obtain high-purity cyclohexanone oxime. The method can also optimize and shorten the cyclohexanone oxime production process under the ammonia oximation process, save equipment investment and reduce energy consumption. DETAILED DESCRIPTION
[0017] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.
[0018] An embodiment of the present invention provides a method for preparing cyclohexanone oxime, comprising the following steps:
[0019] 1) Heterogeneous ammonia oxime reaction: hydrogen peroxide and gaseous ammonia are mixed in a feed mixer and then enter a reaction mixer to generate hydroxylamine and water (see formula (I)); cyclohexanone and an inert organic solvent are mixed in another feed mixer and then enter a reaction mixer together with the obtained hydroxylamine and water for mixing reaction to generate cyclohexanone oxime and water (see formula (II)); finally, all materials enter a heterogeneous ammonia oxime reactor and undergo an ammonia oxime reaction to obtain a crude product containing cyclohexanone oxime; this arrangement is to improve the utilization efficiency of the raw materials so that the reaction can be as complete as possible;
[0020] NH3+H2O2→NH2·OH+H2O (I)
[0021] NH2·OH+C6H 10 O→C6H 10 NO+H2O (II)
[0022] The overall reaction equation for the above two reactions is:
[0023] NH3+H2O2+C6H 10 O→C6H 10 NO+2H2O (III)
[0024] 2) Purification of cyclohexanone oxime: The crude product containing cyclohexanone oxime obtained in step 1) is separated into an oil phase and a small amount of aqueous phase containing a catalyst by decantation, and cyclohexanone oxime and a heterogeneous solvent (inert organic solvent) are separated by a distillation tower or a rectification tower (depending on the boiling point of the material), the inert solvent is recovered at the top of the tower, and cyclohexanone oxime is taken out from the bottom of the tower.
[0025] In the specific implementation, in step 1), the concentration of the hydrogen peroxide is 25-35wt%. The molar ratio of the hydrogen peroxide to cyclohexanone is (1-1.4):1, and the molar ratio of the ammonia gas to cyclohexanone is (1-1.4):1. In order to ensure the complete reaction of cyclohexanone and the high utilization rate of the hydrogen peroxide and the ammonia gas, the molar ratio of the hydrogen peroxide to cyclohexanone is further preferably (1.1-1.3):1, and the molar ratio of the ammonia gas to cyclohexanone is (1.1-1.3):1.
[0026] In the specific implementation, in step 1), the reaction temperature of the heterogeneous ammoximation reaction is 50-100° C., more preferably 75-90° C. This setting is to ensure sufficient reaction while ensuring high selectivity and high conversion rate of the reaction.
[0027] In the specific implementation, in step 1), the pressure of the heterogeneous ammoximation reaction is 0.1 MPa·G to 0.8 MPa·G, and more preferably 0.3 MPa·G to 0.5 MPa·G. The purpose of this setting is to ensure the solubility of ammonia in the heterogeneous solution under the selected certain pressure.
[0028] In the specific implementation, in step 1), the inert organic solvent of the heterogeneous ammoximation reaction is selected from one or a mixture of two of n-hexane, isoheptane, cycloheptane, n-heptane, isobutanol, cyclohexane and xylene; more preferably one of n-hexane, cyclohexane and isoheptane. This arrangement is to ensure that the inert solvent does not participate in the reaction, is miscible with cyclohexanone oxime, is immiscible with water, has a large boiling point difference with cyclohexanone oxime, and is easy to be separated by subsequent distillation.
[0029] In the specific implementation, in step 1), the mass ratio of the inert organic solvent to cyclohexanone is 1 to 10:1, more preferably 4 to 6:1; the mass ratio of water to the inert organic solvent is 1 to 10:1. This is to ensure that the inert solvent can dissolve cyclohexanone oxime without being excessive, to form a certain interface in the reactor, and to reduce steam consumption during subsequent separation processes.
[0030] In the specific implementation, in step 1), the catalyst for the heterogeneous ammoximation reaction is titanium silicon molecular sieve, and its content is 2-10wt% based on the mass of the catalyst in the reactor circulating kettle liquid, and more preferably 3-6wt%. This setting is to ensure sufficient catalyst so that the reaction can run efficiently, but not excessive, which reduces the subsequent oil-water separation effect.
[0031] The present invention is further described below in conjunction with specific embodiments.
[0032] Embodiment 1:
[0033] This embodiment provides a method for preparing cyclohexanone oxime, comprising the following steps:
[0034] 1) Heterogeneous ammonia oximation reaction: hydrogen peroxide and gaseous ammonia are mixed in a feed mixer and then enter a reaction mixer; cyclohexanone and cyclohexane are mixed in another feed mixer and then enter the reaction mixer, and a crude product containing cyclohexanone oxime is obtained by a heterogeneous ammonia oximation reaction at a temperature of 85° C. and a pressure of 0.3 MPa; the concentration of the hydrogen peroxide is 30 wt %; the molar ratio of the hydrogen peroxide to cyclohexanone is 1.2:1, and the molar ratio of the gaseous ammonia to cyclohexanone is 1.2:1; the mass ratio of cyclohexane to cyclohexanone is 4.5:1; the catalyst is TS-1 titanium silicon molecular sieve, and its content is 3.5 wt %.
[0035] 2) Purification of cyclohexanone oxime: The crude product containing cyclohexanone oxime obtained in step 1) is separated into an oil phase and an aqueous phase containing about 0.5 wt % of a catalyst by decantation (controlling the boundary at 90%), and the cyclohexanone oxime and cyclohexane are separated from the oil phase by distillation, and the cyclohexanone oxime is obtained in the bottom of the tower.
[0036] The content of cyclohexanone extracted from the distillation tower bottom used in the distillation described in this embodiment is 0.015wt%, and the content of cyclohexanone oxime is 99.5wt%, which meets the requirements of cyclohexanone oxime content being above 99.5wt% and cyclohexanone content being less than 0.5wt%.
[0037] Embodiment 2:
[0038] The difference between this embodiment and embodiment 1 is that the heterogeneous ammoximation reaction parameters of step 1) of this embodiment are: reaction temperature 82° C., pressure 0.32 MPa; the inert organic solvent is n-hexane, and the mass ratio of n-hexane to cyclohexanone is 4.5:1. The remaining steps and parameters are the same as those of embodiment 1.
[0039] The cyclohexanone content in the distillation tower bottom used in the distillation described in this embodiment is 0.010wt%, and the cyclohexanone oxime content is 99.88wt%, which meets the requirements that the cyclohexanone oxime content is more than 99.5wt% and the cyclohexanone content is less than 0.5wt%.
[0040] Embodiment 3:
[0041] The difference between this embodiment and embodiment 2 is that the heterogeneous ammoximation reaction parameters of step 1) of this embodiment are: the molar ratio of hydrogen peroxide to cyclohexanone is 1.3:1, the molar ratio of the gaseous ammonia to cyclohexanone is 1.3:1, and the remaining steps and parameters are the same as those of embodiment 1.
[0042] The cyclohexanone content in the distillation tower bottom used in the distillation described in this embodiment is 0.017wt%, and the cyclohexanone oxime content is 99.8wt%, which meets the requirements that the cyclohexanone oxime content is above 99.5wt% and the cyclohexanone content is less than 0.5wt%.
[0043] Embodiment 4:
[0044] The difference between this embodiment and embodiment 1 is that the heterogeneous ammoximation reaction parameters of step 1) of this embodiment are: the mass ratio of cyclohexane to cyclohexanone is 3.0:1, the catalyst content is 5.0%wt, and the remaining steps and parameters are the same as those of embodiment 1.
[0045] The cyclohexanone content in the distillation tower bottom used in the distillation described in this embodiment is 0.07wt%, and the cyclohexanone oxime content is 99.8wt%, which meets the requirements that the cyclohexanone oxime content is more than 99.5wt% and the cyclohexanone content is less than 0.5wt%.
[0046] Embodiment 5:
[0047] The difference between this embodiment and embodiment 1 is that the heterogeneous ammoximation reaction parameters of step 1) of this embodiment are: the temperature is 80° C., the pressure is 0.5 MPa, the catalyst content is 4% wt, and the remaining steps and parameters are the same as in embodiment 1.
[0048] The cyclohexanone content in the distillation tower bottom used in the distillation described in this embodiment is 0.08wt%, and the cyclohexanone oxime content is 99.8wt%, which meets the requirements that the cyclohexanone oxime content is above 99.5wt% and the cyclohexanone content is less than 0.5wt%.
[0049] Embodiment 6:
[0050] The difference between this embodiment and embodiment 1 is that the heterogeneous ammoximation reaction parameters of step 1) of this embodiment are: the inert organic solvent is n-hexane, the mass ratio of n-hexane to cyclohexanone is 3.0:1, the catalyst content is 3.0%wt, and the remaining steps and parameters are the same as those of embodiment 1.
[0051] The cyclohexanone content in the distillation tower bottom used in the distillation described in this embodiment is 0.09wt%, and the cyclohexanone oxime content is 99.8wt%, which meets the requirements that the cyclohexanone oxime content is above 99.5wt% and the cyclohexanone content is less than 0.5wt%.
[0052] Embodiment 7:
[0053] The difference between this embodiment and embodiment 1 is that the heterogeneous ammoximation reaction parameters of step 1) of this embodiment are: the inert organic solvent is isoheptane, the mass ratio of isoheptane to cyclohexanone is 4:1, the catalyst content is 4.0%wt, and the remaining steps and parameters are the same as those of embodiment 1.
[0054] The cyclohexanone content in the distillation tower bottom used in the distillation described in this embodiment is 0.08wt%, and the cyclohexanone oxime content is 99.7wt%, which meets the requirements of cyclohexanone oxime content being above 99.5wt% and cyclohexanone content being less than 0.5wt%.
[0055] Comparative Example 1:
[0056] The difference between this comparative example and Example 2 is that the heterogeneous ammoximation reaction parameters of step 1) of this comparative example are: reaction temperature 35° C., pressure 0.32 MPa, and the remaining steps and parameters are the same as Example 2.
[0057] The distillation bottom used in the distillation of this comparative example has a cyclohexanone content of 98wt% and a cyclohexanone oxime content of 1.6wt%. The cyclohexanone conversion rate is too low and does not meet the requirements of a cyclohexanone oxime content of more than 99.5wt% and a cyclohexanone content of less than 0.5wt%.
[0058] Comparative Example 2:
[0059] The difference between this comparative example and Example 2 is that the heterogeneous ammoximation reaction parameters of step 1) of this comparative example are: reaction temperature 80° C., pressure 0 MPa, and the remaining steps and parameters are the same as Example 2.
[0060] The cyclohexanone content in the distillation tower bottom used in the distillation of this comparative example is 63wt%, and the cyclohexanone oxime content is 35.7wt%. The cyclohexanone conversion rate is too low and does not meet the requirements of cyclohexanone oxime content being above 99.5wt% and cyclohexanone content being less than 0.5wt%.
[0061] Comparative Example 3:
[0062] The difference between this comparative example and Example 2 is that the heterogeneous ammoximation reaction parameters of step 1) of this comparative example are: the inert organic solvent is n-heptane, the mass ratio of n-heptane to cyclohexanone is 5:1, and the remaining steps and parameters are the same as Example 2.
[0063] The cyclohexanone content in the distillation tower bottom used in the distillation of this comparative example is 96wt%, and the cyclohexanone oxime content is 2.8wt%. The cyclohexanone conversion rate is too low and does not meet the requirements of cyclohexanone oxime content being above 99.5wt% and cyclohexanone content being less than 0.5wt%.
[0064] Comparative Example 4:
[0065] The difference between this comparative example and Example 2 is that the heterogeneous ammoximation reaction parameters of step 1) of this comparative example are: the content of the catalyst is 1wt%, and the remaining steps and parameters are the same as Example 2.
[0066] The cyclohexanone content in the distillation tower used in the distillation of this comparative example is 30.7wt%, and the cyclohexanone oxime content is 67.0wt%. The cyclohexanone conversion rate is too low and does not meet the requirements of cyclohexanone oxime content being above 99.5wt% and cyclohexanone content being less than 0.5wt%.
[0067] Comparative Example 5:
[0068] The difference between this comparative example and Example 1 is that in step 1) of this comparative example, the molar ratio of the hydrogen peroxide to cyclohexanone is 0.8:1, the molar ratio of the ammonia gas to cyclohexanone is 0.8:1; the mass ratio of n-hexane to cyclohexanone is 3:1, the content of the catalyst is 3wt%, and the remaining steps and parameters are the same as in Example 1.
[0069] The cyclohexanone content in the distillation tower used in the distillation of this comparative example is 23wt%, and the cyclohexanone oxime content is 62.6wt%. The cyclohexanone conversion rate is too low and does not meet the requirements of cyclohexanone oxime content being above 99.5wt% and cyclohexanone content being less than 0.5wt%.
[0070] Comparative Example 6:
[0071] The difference between this comparative example and Example 2 is that the heterogeneous ammoximation reaction parameters of step 1) of this comparative example are: the inert organic solvent is cycloheptane, the mass ratio of cycloheptane to cyclohexanone is 2:1; the content of the catalyst is 5wt%, and the remaining steps and parameters are the same as Example 2.
[0072] The cyclohexanone content of the distillation tower used in the distillation of this comparative example is 95wt%, and the cyclohexanone oxime content is 4.0wt%. The cyclohexanone conversion rate is too low and does not meet the requirements of cyclohexanone oxime content being above 99.5wt% and cyclohexanone content being less than 0.5wt%.
[0073] Comparative Example 7:
[0074] The difference between this comparative example and comparative example 6 is that the inert organic solvent in this comparative example is, the mass ratio of the isobutanol to the cyclohexanone is 5:1; the content of the catalyst is 3.5wt%; and the remaining steps and parameters are the same as those in comparative example 6.
[0075] The cyclohexanone content of the distillation tower used in the distillation of this comparative example is 96.7wt%, and the cyclohexanone oxime content is 1.7wt%. The cyclohexanone conversion rate is too low and does not meet the requirements of cyclohexanone oxime content being above 99.5wt% and cyclohexanone content being less than 0.5wt%.
[0076] Comparative Example 8:
[0077] The difference between this comparative example and comparative example 6 is that in step 1) of this comparative example, the molar ratio of hydrogen peroxide to cyclohexanone is 1.15:1, and the molar ratio of ammonia gas to cyclohexanone is 1.21:1; the inert organic solvent is cycloheptane, and the mass ratio of cycloheptane to cyclohexanone is 5:1; the remaining steps and parameters are the same as those in comparative example 6.
[0078] The cyclohexanone content in the distillation tower bottom used in the distillation of this comparative example is 97wt%, and the cyclohexanone oxime content is 1.85wt%. The cyclohexanone conversion rate is too low and does not meet the requirements of cyclohexanone oxime content being above 99.5wt% and cyclohexanone content being less than 0.5wt%.
[0079] In summary, the method optimizes and shortens the cyclohexanone oxime production process under the ammoximation process, saves equipment investment and reduces energy consumption.
[0080] The preferred 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.
[0081] 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.
[0082] 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.
Claims
1. A method for preparing cyclohexanone oxime, characterized in that: The following steps are involved: 1) Generation of cyclohexanone oxime: hydrogen peroxide and gaseous ammonia are mixed in a feed mixer and then enter a reaction mixer; cyclohexanone and an inert organic solvent are mixed in another feed mixer and then enter the reaction mixer, and a crude product containing cyclohexanone oxime is obtained through an ammoximation reaction; 2) Purification of cyclohexanone oxime: The crude product containing cyclohexanone oxime obtained in step 1) is separated into an oil phase and a water phase containing a catalyst by decantation. 3) The oil phase obtained in step 2) is separated into the inert solvent and the pure cyclohexanone oxime by distillation or rectification.
2. The method for preparing cyclohexanone oxime according to claim 1, characterized in that: In step 1), the concentration of the hydrogen peroxide is 25-35wt%.
3. The method for preparing cyclohexanone oxime according to claim 1, characterized in that: In step 1), the reaction temperature of the heterogeneous ammoximation reaction is 50-100°C.
4. The method for preparing cyclohexanone oxime according to claim 1, characterized in that: The pressure of the heterogeneous ammoximation reaction is 0.1 MPa·G to 0.8 MPa·G.
5. The method for preparing cyclohexanone oxime according to claim 1, characterized in that: In step 1), the inert organic solvent is selected from one or a mixture of two of n-hexane, isoheptane, benzene, n-heptane, isobutanol, cyclohexane and xylene.
6. The method for preparing cyclohexanone oxime according to claim 1, characterized in that: In step 1), the mass ratio of the inert organic solvent to cyclohexanone is 1 to 10:
1.
7. The method for preparing cyclohexanone oxime according to claim 1, characterized in that: In step 1), the catalyst for the ammoximation reaction is titanium silicon molecular sieve, and its content is 2-10 wt%.
8. The method for preparing cyclohexanone oxime according to claim 1, characterized in that: Step 2) further comprises the step of separating cyclohexanone oxime and the inert organic solvent by distillation or rectification after the decantation separation.