Catalytic synthesis method for preparing high-purity chloropinacolone
Through the catalyst combined with photocatalytic method and a three-stage exhaust gas absorption system, the problems of difficult solvent recovery, high impurities and high energy consumption in the preparation of monochloropinone in the prior art are solved, and the efficient preparation of high-purity monochloropinone is achieved, reducing costs and energy consumption.
Patent Information
- Application Number
- CN202510379939.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-28
- Publication Date
- 2025-07-04
AI Technical Summary
In the prior art, the preparation process of monochloropinone has problems such as difficulty in solvent distillation and recovery, high impurity content and high energy consumption of dichloropinone produced by side reactions, which affect product quality and production efficiency.
The catalyst combined with photocatalytic method is used to prepare high-purity monochloroprene by controlling the chlorine inlet speed and temperature and combining with the three-stage exhaust absorption system, and avoiding the use of methanol as a solvent.
It significantly reduces raw material costs, reduces by-product content, improves product purity and yield, reduces energy consumption, and has higher safety.
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Figure CN120247672A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the technical field of fine chemicals, and specifically relates to a catalytic synthesis method for preparing high-purity 1-chloropinacolone. Background Art
[0002] 1-Chloropinacolone is a key organic raw material with a rather wide range of uses. Its scientific name is 1-chloro-3,3-dimethyl-2-butanone, and its English name is 1-Choropinacolone. It presents as a colorless or slightly yellowish transparent liquid, with a molecular weight of 134.5 and a CAS number of 13547-70-1.
[0003] 1-Chloropinacolone has a strong ability to undergo condensation reactions with many compounds, so it plays an important role in the field of pesticide preparation and can be used to produce a series of pesticide products such as triadimefon, triadimenol, diniconazole, diniconazole-M, paclobutrazol, and bensulide triazole alcohol.
[0004] Currently, the common preparation method of 1-chloropinacolone is to use pinacolone as the starting material, carry out a chlorination reaction by passing chlorine with methanol as the solvent, and achieve the goal through a rectification and purification process. However, this synthesis process has many deficiencies. For example, the solvent rectification and recovery are extremely difficult (because a large amount of hydrochloric acid is generated during the chlorination reaction and reacts with methanol), and the content of the impurity dichloropinacolone produced by side reactions in the product is relatively high, which seriously affects the production of downstream products. At the same time, the energy consumption during the later treatment of the product is also quite high. In view of this, there is an urgent need to explore a new process that is easy to achieve solvent recovery and easy to purify the product to replace the existing process for production, so as to improve the production situation and product quality. Summary of the Invention
[0005] In view of the above problems, the embodiments of this application provide a catalytic synthesis method for preparing high-purity 1-chloropinacolone, and provide a method for preparing 1-chloropinacolone using a catalyst combined with photocatalysis that is safe, efficient, and has few by-products.
[0006] According to one aspect of the embodiments of this application, a catalytic synthesis method for preparing high-purity 1-chloropinacolone is provided. The catalytic synthesis method for preparing high-purity 1-chloropinacolone includes the following steps:
[0007] S1: After introducing a certain amount of liquid-phase pinacolone into the vaporization kettle, start stirring, and heat the pinacolone to 100-110 °C to vaporize the liquid-phase pinacolone into gaseous pinacolone;
[0008] S2: After adding a certain amount of catalyst into the reactor, introduce the gaseous pinacolone into the above reactor, turn on the lamp source in the reactor and turn on the light source, and pre-connect the chlorine gas pipeline at the above reactor;
[0009] S3: Open the chlorine gas valve at the above-mentioned reactor, and introduce chlorine gas into the reactor in three stages. The total time for introducing chlorine gas is 6 - 8 hours. Introduce the synthesis tail gas into the tail gas treatment system. The three stages include an initial stage, a middle stage, and a later stage. Among them, the chlorine gas introduction rate in the middle stage is greater than that in the initial stage and the later stage;
[0010] S4: Control the outlet reflux of the reactor during the reaction in S3 above, and control the gas phase temperature ≤ 100 °C so that the unreacted pinacolone and the product monochloropinacolone reflux into the reactor for full reaction;
[0011] S5: After the reaction in S3 above ends, turn off the light source, lower the system temperature to room temperature, extract the supernatant as the monochloropinacolone product, and recycle the sedimented catalyst to the next batch of reactions;
[0012] In some embodiments, in S2, a quantitative catalyst is added to the reactor. The catalyst is one of azobisisobutyronitrile, benzoyl peroxide, ammonium persulfate, diisopropylbenzene peroxide, ferric chloride, and tert-butyl peroxybenzoate. The catalyst addition amount is 0.2 - 1.5% of the raw material pinacolone equivalent.
[0013] In some embodiments, in S2, the lamp tube light source in the reactor is connected and turned on. The light wavelength of the lamp tube light source is 400 - 500 nm.
[0014] In some embodiments, in S2, the lamp tube light source in the reactor is connected and turned on. The luminous flux is 2000 - 6000 lux.
[0015] In some embodiments, in S2, the chlorine gas pipeline at the above-mentioned reactor is pre-connected. The chlorine gas content in the chlorine gas pipeline > 99.5%.
[0016] In some embodiments, the molar ratio of pinacolone to chlorine gas in the reactor is 1:1 - 1.2.
[0017] In some embodiments, in S3, the synthesis tail gas is introduced into the tail gas treatment system. The tail gas treatment system uses a three-stage absorption method. The first stage uses water absorption, the second stage uses water absorption, and the third stage uses liquid alkali absorption.
[0018] The beneficial effects in this application are:
[0019] 1. The method of the present invention eliminates the dependence on solvents in traditional reactions, thereby significantly reducing the raw material cost. By not using methanol as a solvent, the present invention also reduces potential safety risks and can avoid the phenomenon of excessive by-products caused by the reaction of methanol with hydrochloric acid (hydrochloric acid is generated during the chlorination reaction process).
[0020] 2. By controlling the feeding rate of chlorine gas, in the early stage, a small amount of chlorine gas is fed to confirm the initiation of the reaction, then the feeding rate of chlorine is gradually increased, and in the later stage of the reaction, the feeding rate of chlorine is slowed down, which can effectively improve the purity of pinacolone monochloride in the reaction process and reduce the content of by-products.
[0021] 3. In the catalytic combined with photocatalytic technology adopted in the present invention, the raw materials are easily available, the catalyst is easily recovered, and it has the advantages of less pollution, high selectivity, good product purity and properties, etc.
[0022] The above description is only an overview of the technical solution of this application. In order to be able to understand the technical means of this application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of this application more obvious and understandable, the following specific embodiments of this application are specifically given. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of this application. And throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:
[0024] Figure 1 is the mass spectrum of the product obtained in Example 1 of this application;
[0025] Figure 2 is the schematic production flow diagram of the embodiment of this application. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0026] Hereinafter, embodiments of the technical solution of this application will be described in detail with reference to the drawings. The following embodiments are only used to illustrate the technical solution of this application more clearly, so they are only examples and cannot be used to limit the protection scope of this application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above drawings are intended to cover non-exclusive inclusion.
[0027] Specifically, please refer to Figure 1 and Figure 2 . Figure 1 is the mass spectrum of the product obtained in Example 1 of this application, Figure 2 is the schematic production flow diagram of the embodiment of this application. The catalytic synthesis method for preparing high-purity pinacolone monochloride includes the following steps:
[0028] S1: After introducing a certain amount of liquid pinacolone into the gasification axe, start stirring, heat the pinacolone to 100 - 110 °C to vaporize the liquid pinacolone into gaseous pinacolone;
[0029] S2: After adding a certain amount of catalyst into the reactor, introduce the gaseous pinacolone into the above reactor, turn on the lamp light source in the reactor and open the light source, and pre-connect the chlorine gas pipeline at the above reactor;
[0030] S3: Open the chlorine gas valve at the above reactor, introduce chlorine gas into the reactor in three stages, with a total chlorine gas introduction time of 6 - 8 hours, and introduce the synthesis tail gas into the tail gas treatment system. The three stages include the initial stage, the middle stage, and the later stage. Among them, the chlorine gas introduction rate in the middle stage is greater than that in the initial stage and the later stage;
[0031] S4: During the reaction in S3 above, control the outlet reflux of the reactor, and control the gas phase temperature ≤ 100 °C to make the unreacted pinacolone and the product monochloropinacolone reflux into the reactor for full reaction;
[0032] S5: After the reaction in S3 above ends, turn off the light source, lower the system temperature to room temperature, extract the supernatant as the monochloropinacolone product, and settle the catalyst for reuse in the next batch of reactions;
[0033] In some embodiments, in S2, adding a certain amount of catalyst into the reactor, where the catalyst is one of azobisisobutyronitrile, benzoyl peroxide, ammonium persulfate, diisopropylbenzene peroxide, ferric chloride, tert-butyl peroxybenzoate, and the catalyst addition amount is 0.2 - 1.5% of the raw material pinacolone equivalent.
[0034] In some embodiments, in S2, turning on the lamp light source in the reactor and opening the light source, where the light wavelength of the lamp light source is 400 - 500 nm.
[0035] In some embodiments, in S2, turning on the lamp light source in the reactor and opening the light source, where the luminous flux is 2000 - 6000 lux.
[0036] In some embodiments, in S2, pre-connecting the chlorine gas pipeline at the above reactor, where the chlorine content in the chlorine gas pipeline > 99.5%.
[0037] In some embodiments, the molar ratio of pinacolone to chlorine gas in the reactor is 1:1 - 1.2.
[0038] In some embodiments, in S3, introducing the synthesis tail gas into the tail gas treatment system, where the tail gas treatment system uses a three-stage absorption method, the first stage uses water absorption, the second stage uses water absorption, and the third stage uses liquid alkali absorption.
[0039] Example 1
[0040] In this example, 1-chloropinacolone was prepared through the following steps: 200 g of pinacolone was added into a dry 500-ml four-necked flask, and the temperature of the system was raised to 110 °C. The vaporized pinacolone was introduced into the reactor, and 1.34 g of benzoyl peroxide was previously added into the reactor. When the temperature of the reactor reached the set range, the light source was turned on (450 nm, 4000 lux). The chlorine valve of the reactor was opened, and a small amount of chlorine was introduced to confirm the initiation of the reaction. Then, the chlorine feeding rate was gradually increased, and the chlorine feeding rate was slowed down in the later stage of the reaction. The total chlorine feeding time was 8 h. The generated tail gas was directed to the tail gas treatment system, which adopted a three-stage absorption process. Water was used for absorption in the first and second stages, and liquid alkali was used for absorption in the third stage. Sampling and detection were carried out regularly. When the concentration of the raw material peak of pinacolone dropped below 1%, the reaction was determined to be completed. The reaction system was cooled to room temperature, the light source was turned off, and after sedimentation for 12 h, the supernatant was 259 g of 1-chloropinacolone product. The catalyst remained in the reaction flask for continued reuse. In actual experiments, the reaction effect deteriorated after 8 - 10 times of reuse, and at this time, a new catalyst was replaced.
[0041] Attached Figure 2 shows the mass spectrum of the 1-chloropinacolone product prepared in this example. In the mass spectrum, the molecular ion peak of 1-chloropinacolone is located at 134, indicating the presence of a carbonyl group in the product, and the carbonyl carbon can undergo fragmentation. All the peaks that appeared corresponded to the characteristic peaks of 1-chloropinacolone. The spectral data confirmed that the 1-chloropinacolone was successfully prepared by the scheme of the present invention. After detection, the yield of 1-chloropinacolone was 95.5%, and the detection quality was as follows: 1-chloropinacolone 98.1%, pinacolone 0.7%, and dichloropinacolone 0.9%. As shown in Table 1.
[0042] Example 2
[0043] In this example, 1-chloropinacolone was prepared through the following steps: 200 g of pinacolone was added into a dry 500-ml four-necked flask, and the temperature of the system was raised to 110 °C. The vaporized pinacolone was introduced into the reactor, and 0.9 g of azobisisobutyronitrile was previously added into the reactor. When the temperature of the reactor reached the set range, the light source was turned on (450 nm, 4000 lux). The chlorine valve of the reactor was opened, and a small amount of chlorine was introduced to confirm the initiation of the reaction. Then, the chlorine feeding rate was gradually increased, and the chlorine feeding rate was slowed down in the later stage of the reaction. The total chlorine feeding time was 8 h. The generated tail gas was directed to the tail gas treatment system, which adopted a three-stage absorption process. Water was used for absorption in the first and second stages, and liquid alkali was used for absorption in the third stage. Sampling and detection were carried out regularly. When the concentration of the raw material peak of pinacolone dropped below 1%, the reaction was determined to be completed. The reaction system was cooled to room temperature, the light source was turned off, and after sedimentation for 12 h, the supernatant was 258.5 g of 1-chloropinacolone product. The catalyst remained in the reaction flask for continued reuse. In actual experiments, the reaction effect deteriorated after 8 - 10 times of reuse, and at this time, a new catalyst was replaced.
[0044] Upon detection, the yield of 3,3,3-trichloro-2-butanone is 95.6%, and the detected quality is as follows: 3,3,3-trichloro-2-butanone 98.4%, pinacolone 0.8%, dichloropinacolone 0.6%. As shown in Table 1.
[0045] Example 3
[0046] Charge 200 g of pinacolone into a 500-ml dry four-necked flask, heat the system to 110 °C, and introduce the vaporized pinacolone into the reactor. 0.9 g of azobisisobutyronitrile is pre-charged into the reactor. When the reactor temperature reaches the set range, turn on the light source, 500 nm, 5000 lux, open the chlorine valve of the reactor, introduce a small amount of chlorine to confirm the initiation of the reaction, then gradually increase the chlorine feeding rate, and slow down the chlorine feeding rate in the later stage of the reaction. The total chlorine feeding time is 8 h. Guide the generated tail gas to the tail gas treatment system, which adopts a three-stage absorption process. The first and second stages use water absorption, and the third stage uses liquid alkali absorption. Regularly conduct sampling and detection. When the concentration of the raw material peak pinacolone drops below 1%, determine that the reaction is over. Cool the reaction system to room temperature, turn off the light source, and after sedimentation for 12 h, the supernatant is 257.8 g of 3,3,3-trichloro-2-butanone product. The catalyst remains in the reaction flask for continued reuse. In actual experiments, the reaction effect deteriorates after 8 - 10 reuses, and at this time, a new catalyst is replaced.
[0047] Upon detection, the yield of 3,3,3-trichloro-2-butanone is 94.7%, and the detected quality is as follows: 3,3,3-trichloro-2-butanone 97.7%, pinacolone 0.8%, dichloropinacolone 1.3%. As shown in Table 1
[0048] Example 4
[0049] Charge 200 g of pinacolone into a 500-ml dry four-necked flask, heat the system to 110 °C, and introduce the vaporized pinacolone into the reactor. 1.26 g of ammonium persulfate is pre-charged into the reactor. When the reactor temperature reaches the set range, turn on the light source, 400 nm, 5000 lux, open the chlorine valve of the reactor, introduce a small amount of chlorine to confirm the initiation of the reaction, then gradually increase the chlorine feeding rate, and slow down the chlorine feeding rate in the later stage of the reaction. The total chlorine feeding time is 6 h. Guide the generated tail gas to the tail gas treatment system, which adopts a three-stage absorption process. The first and second stages use water absorption, and the third stage uses liquid alkali absorption. Regularly conduct sampling and detection. When the concentration of the raw material peak pinacolone drops below 1%, determine that the reaction is over. Cool the reaction system to room temperature, turn off the light source, and after sedimentation for 12 h, the supernatant is 258.7 g of 3,3,3-trichloro-2-butanone product. The catalyst remains in the reaction flask for continued reuse. In actual experiments, the reaction effect deteriorates after 5 reuses, and at this time, a new catalyst is replaced.
[0050] Upon detection, the yield of 3,3,3-trichloro-2-butanone is 95%, and the detected quality is as follows: 3,3,3-trichloro-2-butanone 97.6%, pinacolone 0.8%, dichloropinacolone 1.4%.
[0051] As shown in Table 1.
[0052]
[0053] Based on the analysis of the above table data, it can be clearly seen that the pinacolone monochloride prepared by the synthesis method of the present invention not only has a relatively high product yield, but also has a relatively high purity, and the content of impurities is very low. In contrast, the overall quality of the product prepared without light and catalyst is significantly lower than that of the product obtained by the present invention. This comparison fully demonstrates the significant advantages of the present invention in terms of technical effects.
[0054] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be covered by the scope of the claims and the description of the present application. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.
Claims
1. A catalytic synthesis method for preparing high-purity pinacolone monochloride, characterized in that, It includes the following steps: S1: Inject a certain amount of liquid pinacolone into the gasification ax, start stirring, and heat the pinacolone to 100 - 110 °C to vaporize the liquid pinacolone into gaseous pinacolone; S2: Put a certain amount of catalyst into the reactor, then introduce the gaseous pinacolone into the above reactor, turn on the lamp light source inside the reactor and turn on the light source, and pre-connect the chlorine gas pipeline at the above reactor; S3: Open the chlorine gas valve at the above reactor, introduce chlorine gas into the reactor in three stages, with a total chlorine gas introduction time of 6 - 8 hours, and introduce the synthesis tail gas into the tail gas treatment system. The three stages include the initial stage, the middle stage, and the later stage. Among them, the chlorine gas introduction speed in the middle stage is greater than that in the initial stage and the later stage; S4: Control the outlet reflux of the reactor during the reaction in S3, and control the gas phase temperature ≤ 100 °C to make the unreacted pinacolone and the product monochloropinacolone reflux into the reactor for full reaction; S5: After the reaction in S3 ends, turn off the light source, lower the system temperature to room temperature, extract the supernatant as the monochloropinacolone product, and settle the catalyst for reuse in the next batch of reactions; The reaction equation is as follows:
2. The catalytic synthesis method for preparing high-purity pinacolone monochloride according to claim 1, characterized in that, In S2, when putting a certain amount of catalyst into the reactor, the catalyst is one of azobisisobutyronitrile, benzoyl peroxide, ammonium persulfate, diisopropylbenzene peroxide, ferric trichloride, tert-butyl peroxybenzoate, and the catalyst addition amount is 0.2 - 1.5% of the raw material pinacolone equivalent.
3. The catalytic synthesis method for preparing high-purity pinacolone monochloride according to claim 1, characterized in that, In S2, when turning on the lamp light source inside the reactor and turning on the light source, the light wavelength of the lamp light source is 400 - 500 nm.
4. The catalytic synthesis method for preparing high-purity pinacolone monochloride according to claim 1, characterized in that, In S2, when turning on the lamp light source inside the reactor and turning on the light source, the luminous flux is 2000 - 6000 lux.
5. The catalytic synthesis method for preparing high-purity pinacolone monochloride according to claim 1, characterized in that, In S2, when pre-connecting the chlorine gas pipeline at the above reactor, the chlorine gas content in the chlorine gas pipeline > 99.5%.
6. The catalytic synthesis method for preparing high-purity pinacolone monochloride according to claim 1, characterized in that, The molar ratio of pinacolone to chlorine gas in the reactor is 1:1 - 1.
2.
7. The catalytic synthesis method for preparing high-purity pinacolone monochloride according to claim 1, characterized in that, In S3, when introducing the synthesis tail gas into the tail gas treatment system, the tail gas treatment system uses a three-stage absorption method. The first stage uses water absorption, the second stage uses water absorption, and the third stage uses liquid alkali absorption.