CN109265329B - Preparation method of 3, 5-dichloro-2-pentanone - Google Patents
Preparation method of 3, 5-dichloro-2-pentanone Download PDFInfo
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Abstract
The invention relates to the field of fine chemical engineering, and discloses a preparation method of 3, 5-dichloro-2-pentanone, which is characterized by comprising the following steps: in a system without a solvent, contacting alpha-acetyl-gamma-butyrolactone and sulfonyl chloride for chlorination reaction, then mixing the material obtained by the chlorination reaction with water, and dropwise adding hydrochloric acid into the obtained mixture for ring-opening reaction. The method uses cheap industrial chemicals as raw materials, realizes organic solvent-free one-pot reaction, simplifies process operation, reduces three wastes and production cost, and avoids pollution caused by using a metal catalyst.
Description
Technical Field
The invention relates to the field of fine chemical engineering, and particularly relates to a preparation method of 3, 5-dichloro-2-pentanone.
Background
3, 5-dichloro-2-pentanone is an important intermediate for synthesizing medicines and pesticides, in particular to an important intermediate for synthesizing bactericide prothioconazole developed by Bayer company. In 1975, 2-methyl-2-hydroxytetrahydrofuran is used as a raw material, ring opening is carried out by hydrochloric acid, and chlorination is carried out by sulfonyl chloride to generate the intermediate, but the yield of the process is relatively low, and the yield of the later step is only 70%. In 1983, a document reports that 3-butene-2-ketone and dichloromethane are used as raw materials, and the intermediate can be obtained by photochemical addition reaction under the catalysis of monovalent copper ions, and the reaction uses a metal catalyst and photochemical reaction conditions, so that the industrial implementation of the process is relatively difficult. In addition, CN106278850A reports a method for obtaining 3, 5-dichloro-2-pentanone through a three-step reaction by using ethyl acetoacetate as a raw material, but the process route has relatively long steps.
At present, the most reported synthetic route is to use alpha-acetyl-gamma-butyrolactone as raw material, separate the raw material through chlorination reaction to obtain alpha-chloro-alpha' -acetyl-gamma-butyrolactone, and then perform ring-opening reaction with hydrochloric acid in the presence of lewis acid catalyst such as aluminum chloride or phase transfer catalyst, or react with hydrochloric acid in the presence of glacial acetic acid. The processes are not only complicated to operate, but also generate a large amount of three wastes in the process of separating the alpha-chloro-alpha' -acetyl-gamma-butyrolactone, and lose the raw material hydrochloric acid which is generated in the reaction and can be used for the next reaction, so that the economy is poor. Moreover, the use of a catalyst in the next reaction step increases the difficulty in treating the three wastes or increases environmental pollution. In CN104292089A, it is described that in the preparation of α -chloro- α' -acetyl- γ -butyrolactone, a small amount of sulfonyl chloride is removed by distillation under reduced pressure, hydrochloric acid and sulfur dioxide are used as crude products in the next reaction. Also, the operation is relatively complicated and the hydrochloric acid, which is a raw material for the next reaction, is lost, and the solvent glacial acetic acid is additionally used in the next reaction, thereby increasing the production cost.
Disclosure of Invention
The invention aims to solve the problems of complex process and environmental pollution of the preparation of 3, 5-dichloro-2-pentanone in the prior art, and provides a preparation method of 3, 5-dichloro-2-pentanone, which is convenient, economic and environment-friendly.
In order to achieve the above object, the present invention provides a method for preparing 3, 5-dichloro-2-pentanone, wherein the method comprises: in a system without a solvent, contacting alpha-acetyl-gamma-butyrolactone and sulfonyl chloride for chlorination reaction, then mixing the material obtained by the chlorination reaction with water, and dropwise adding hydrochloric acid into the obtained mixture for ring-opening reaction.
The method adopts a one-pot method to prepare the 3, 5-dichloro-2-pentanone by the reaction of the raw material alpha-acetyl-gamma-butyrolactone, has simple process, convenient operation and higher yield, shortens the process period, and is more suitable for industrial production; avoids a large amount of three wastes generated in the process of separating the alpha-chloro-alpha' -acetyl-gamma-butyrolactone by the prior process; the method of dripping hydrochloric acid is adopted for feeding, so that the use of Lewis acid catalyst or phase transfer catalyst is avoided, and the method is more economic and environment-friendly.
Detailed Description
The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.
The invention provides a preparation method of 3, 5-dichloro-2-pentanone, which comprises the following steps: in a system without a solvent, contacting alpha-acetyl-gamma-butyrolactone and sulfonyl chloride for chlorination reaction, then mixing the material obtained by the chlorination reaction with water, and dropwise adding hydrochloric acid into the obtained mixture for ring-opening reaction.
According to the present invention, in order to increase the yield of 3, 5-dichloro-2-pentanone and reduce the production cost, it is preferable that the molar ratio of the amount of α -acetyl- γ -butyrolactone to the amount of sulfonyl chloride in the chlorination reaction be 1: 1-1.5, preferably 1: 1-1.05.
According to the invention, the conditions of the chlorination reaction preferably comprise: the reaction temperature is 0-60 ℃, and preferably 0-20 ℃; the reaction time is 0.4-4h, preferably 0.5-2 h. Under the preferred chlorination reaction conditions, 3, 5-dichloro-2-pentanone can be obtained in higher yield.
According to the present invention, the α -acetyl- γ -butyrolactone and sulfonyl chloride are contacted in a manner of mixing the existing reaction raw materials, and preferably, the α -acetyl- γ -butyrolactone and sulfonyl chloride are contacted in a manner of: sulfuryl chloride is added dropwise to the alpha-acetyl-gamma-butyrolactone.
According to the present invention, the dropping rate of sulfuryl chloride into α -acetyl- γ -butyrolactone can be carried out according to conventional rates, and preferably, the dropping rate of sulfuryl chloride is 2 to 6 mol/h.
According to the invention, the preparation method does not need an organic solvent, only a certain amount of water is added after chlorination reaction, and the next operation is directly carried out without separation after the water is added. Preferably, the weight ratio of the amount of water to the amount of α -acetyl- γ -butyrolactone is from 0.1 to 10: 1, preferably 0.2 to 5, more preferably 0.3 to 0.8: 1.
according to the present invention, in order to increase the yield of 3, 5-dichloro-2-pentanone and reduce the production cost, it is preferable that the molar ratio of the amount of hydrochloric acid as HCl to the amount of α -acetyl- γ -butyrolactone used in the ring-opening reaction is 1 to 5: 1, preferably 1.5-2.5: 1.
according to the invention, the concentration of the hydrochloric acid solution is preferably 15 to 36% by weight.
According to the invention, the conditions of the ring-opening reaction preferably comprise: the reaction temperature is 50-120 ℃, and the preferable temperature is 90-110 ℃; the reaction time is 1-15h, preferably 2-6 h. Under the ring-opening reaction condition, the 3, 5-dichloro-2-pentanone can obtain higher yield.
According to the invention, the manner of dripping hydrochloric acid into the mixture enables the preparation method to avoid using Lewis acid catalyst or phase transfer catalyst, thereby being more economic and environment-friendly. Thus, in the preparation process of the present invention, the ring-opening reaction is carried out in the absence of a Lewis acid catalyst and/or a phase transfer catalyst. In order to further increase the yield of 3, 5-dichloro-2-pentanone, the dropwise addition rate of hydrochloric acid, calculated as HCl, is preferably from 1 to 5mol/h, preferably from 2 to 4 mol/h.
According to the present invention, the preparation method preferably further comprises: after the ring-opening reaction is finished, separating the 3, 5-dichloro-2-pentanone from the reaction product. The separation mode can be extraction, and the extraction process can comprise the following steps: adding an extracting agent into the reaction product, and carrying out reduced pressure distillation on the organic layer obtained by extraction. The extractant may be an existing extractant which can be used for extracting 3, 5-dichloro-2-pentanone, for example the extractant is 1, 2-dichloroethane.
The present invention will be described in detail below by way of examples. In the following examples of the present invention,
the yield of 3, 5-dichloro-2-pentanone was calculated by the following formula:
in the formula, Y: yield,%; m isFruit of Chinese wolfberry: the actual yield, g, calculated as the weight of 3, 5-dichloro-2-pentanone obtained multiplied by the purity; m isTheory of things: theoretical yield of 3, 5-dichloro-2-pentanone, g, calculated as the amount of α -acetyl- γ -butyrolactone reacted.
The method for measuring the purity of the sample comprises the following steps: (1) preparing an internal standard solution: weighing 12.5g dimethyl phthalate into a 500ml volumetric flask, dissolving with acetonitrile, fixing the volume to a scale, carrying out ultrasonic treatment, cooling to room temperature, and shaking up for later use. (2) Preparation of standard solutions: accurately weighing 80mg (accurate to 0.1mg) of a 3, 5-dichloro-2-pentanone standard sample into a 50ml volumetric flask, dissolving the standard sample with acetonitrile, transferring 3ml of an internal standard solution into the volumetric flask by using a pipette, fixing the volume to a scale, performing ultrasonic treatment, cooling to room temperature, and shaking up for later use. (3) Preparing a sample solution: weighing 80mg (accurate to 0.1mg) of 3, 5-dichloro-2-pentanone sample into a 50mL volumetric flask, adding acetonitrile to dissolve, transferring 3mL of internal standard solution into the volumetric flask by using a pipette, fixing the volume to a scale, performing ultrasonic treatment, cooling to room temperature, and shaking up for later use. (4) And (3) purity determination: the measuring instrument is an Agilent GC7890 gas chromatograph (the sample introduction amount is 1 mu L), after the instrument is stabilized, the standard solution of the needles is continuously fed, when the peak area relative deviation of two adjacent needles is less than 1%, the internal standard solution, the standard solution and the sample solution are respectively detected, and the purity (%) of the 3, 5-dichloro-2-pentanone is calculated by the following formula:
wherein: csp-concentration of sample solution, mg/ml; rsp-the ratio of the peak area of the item to be measured of the sample solution to the peak area of the internal standard solution; csd-the concentration of the item to be tested, mg/ml, of the standard solution; rsd-the ratio of the peak area of the item to be measured of the standard solution to the peak area of the internal standard solution; p-purity (%) of 3, 5-dichloro-2-pentanone as a standard sample.
Alpha-acetyl-gamma-butyrolactone, available from Beijing coupling technologies, Inc., under the designation Batch No. 20170512; sulfonyl chloride was purchased from Beijing coupling technologies, Inc. under the designation Batch No. 20170812.
Example 1
Adding 261.5g (2mol) of alpha-acetyl-gamma-butyrolactone into a 1000ml four-mouth bottle, controlling the temperature to be 15 ℃, dropwise adding 281g (2.04mol) of sulfonyl chloride at the dropwise adding speed of 4.08mol/h, continuing stirring for 1h at controlled temperature after the dropwise adding is finished until the raw materials are completely converted, and adding 100g of water. Then, the temperature was raised to 100 ℃ and 344.7g of 36 wt% hydrochloric acid (3.4mol of HCl) was added dropwise at a rate of 3.4mol/h based on HCl, and after the addition, stirring was continued for 3 hours under controlled temperature. After the reaction is finished, the temperature is reduced to room temperature, then 500g of 1, 2-dichloroethane is added into the system, liquid is extracted and separated, and the organic layer is subjected to reduced pressure distillation to obtain the 3, 5-dichloro-2-pentanone with the purity of 98 percent and the yield of 90 percent.
Example 2
Adding 261.5g (2mol) of alpha-acetyl-gamma-butyrolactone into a 1000ml four-mouth bottle, controlling the temperature to be 20 ℃, dropwise adding 289g (2.1mol) of sulfonyl chloride at the dropwise adding speed of 2.1mol/h, continuously stirring at the controlled temperature for 0.5h after the dropwise adding is finished until the raw materials are completely converted, and adding 209g of water. Then, the temperature was raised to 110 ℃ and 15 wt% hydrochloric acid 1217g (5mol of HCl) was added dropwise at a rate of 2.5mol/h as HCl, and after the addition, stirring was continued for 6 hours under controlled temperature. After the reaction is finished, the temperature is reduced to room temperature, then 500g of 1, 2-dichloroethane is added into the system, liquid is extracted and separated, and the organic layer is subjected to reduced pressure distillation to obtain 3, 5-dichloro-2-pentanone with the purity of 98 percent and the yield of 89 percent.
Example 3
3, 5-dichloro-2-pentanone was prepared according to the method of example 1, except that the amount of sulfonyl chloride used was 303g (2.2 mol). The yield of 3, 5-dichloro-2-pentanone was 88%.
Example 4
3, 5-dichloro-2-pentanone was prepared according to the method of example 3, except that the temperature was controlled to 40 ℃ before adding sulfuryl chloride dropwise. The yield of 3, 5-dichloro-2-pentanone was 84%.
Example 5
3, 5-dichloro-2-pentanone was prepared according to the method of example 3, except that stirring at controlled temperature was continued for 3h after the completion of the dropwise addition of sulfuryl chloride. The yield of 3, 5-dichloro-2-pentanone was 87%.
Example 6
3, 5-dichloro-2-pentanone was prepared according to the method of example 1, except that the amount of water was 500 g. The yield of 3, 5-dichloro-2-pentanone was 81%.
Example 7
3, 5-dichloro-2-pentanone was prepared according to the method of example 1, except that the amount of hydrochloric acid used was 243.3g (2.4mol of HCl). The yield of 3, 5-dichloro-2-pentanone was 78%.
Example 8
3, 5-dichloro-2-pentanone was prepared according to the method of example 1, except that, after adding water, the temperature was raised to 70 ℃. The yield of 3, 5-dichloro-2-pentanone was 75%.
Example 9
3, 5-dichloro-2-pentanone was prepared according to the method of example 1, except that after the addition of hydrochloric acid was completed, stirring was continued for 10 hours at a controlled temperature. The yield of 3, 5-dichloro-2-pentanone was 84%.
Example 10
3, 5-dichloro-2-pentanone was prepared according to the method of example 1, except that the dropping rate of hydrochloric acid as HCl was 5 mol/h. The yield of 3, 5-dichloro-2-pentanone was 83%.
Comparative example 1
3, 5-dichloro-2-pentanone was prepared according to the method of example 1, except that hydrochloric acid was added not dropwise but directly mixed with the material after the chlorination reaction. The yield of 3, 5-dichloro-2-pentanone was 55%.
Comparative example 2
3, 5-dichloro-2-pentanone was prepared according to the method of example 1, except that the water was replaced with the same weight of glacial acetic acid. The yield of 3, 5-dichloro-2-pentanone was 70%.
It can be seen from the results of the above examples and comparative examples that the preparation method of the present invention does not require a solvent in the chlorination reaction, an organic solvent in the ring-opening reaction, and an intermediate separation process, is simple to operate, does not generate three wastes, and has a high yield of 3, 5-dichloro-2-pentanone. As can be seen from the comparison of example 1 with examples 3, 6 and 7, the use of sulfuryl chloride, water and hydrochloric acid in the preferred range of the present invention can increase the yield of 3, 5-dichloro-2-pentanone; as can be seen from the comparison of example 3 with examples 4 and 5, a higher yield of 3, 5-dichloro-2-pentanone can be obtained under the preferred chlorination reaction conditions of the present invention; as can be seen from the comparison of example 1 with example 8, example 9 and example 10, the hydrochloric acid drop acceleration rate and the ring-opening reaction conditions within the preferred ranges of the present invention can improve the yield of 3, 5-dichloro-2-pentanone; as can be seen from the comparison of example 1 with comparative example 1, 3, 5-dichloro-2-pentanone can be obtained in high yield without a catalyst by adding hydrochloric acid dropwise; as can be seen from the comparison of example 1 with comparative example 2, the present invention has a higher yield using water as a ring-opening reaction solvent than using glacial acetic acid as a ring-opening reaction solvent, and water is cheaper than glacial acetic acid, thereby greatly reducing costs, with the same charge ratio.
The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.
Claims (14)
1. A preparation method of 3, 5-dichloro-2-pentanone is characterized by comprising the following steps: in a system without solvent, contacting alpha-acetyl-gamma-butyrolactone and sulfonyl chloride for chlorination reaction, then mixing the material obtained by the chlorination reaction with water, dropwise adding hydrochloric acid into the obtained mixture for ring-opening reaction,
the weight ratio of the dosage of the water to the dosage of the alpha-acetyl-gamma-butyrolactone is 0.1-10: 1,
in the ring-opening reaction, the molar ratio of the dosage of the hydrochloric acid in terms of HCl to the dosage of the alpha-acetyl-gamma-butyrolactone is 1-5: 1,
the reaction temperature of the ring-opening reaction is 50-120 ℃,
the dropping rate of the hydrochloric acid calculated as HCl is 1-5 mol/h.
2. The production method according to claim 1, wherein, in the chlorination reaction, the molar ratio of the amount of α -acetyl- γ -butyrolactone to the amount of sulfonyl chloride is 1: 1-1.5.
3. The production method according to claim 2, wherein, in the chlorination reaction, the molar ratio of the amount of α -acetyl- γ -butyrolactone to the amount of sulfonyl chloride is 1: 1-1.05.
4. The production method according to any one of claims 1 to 3, wherein the conditions of the chlorination reaction include: the reaction temperature is 0-60 ℃, and the reaction time is 0.4-4 h.
5. The production method according to claim 4, wherein the conditions of the chlorination reaction include: the reaction temperature is 0-20 ℃, and the reaction time is 0.5-2 h.
6. The production method according to any one of claims 1 to 3, wherein α -acetyl- γ -butyrolactone is contacted with sulfuryl chloride in such a manner that: sulfuryl chloride is added dropwise to the alpha-acetyl-gamma-butyrolactone.
7. The production process according to claim 6, wherein the dropping rate of the sulfonyl chloride is 2 to 6 mol/h.
8. The production method according to any one of claims 1 to 3, wherein the weight ratio of the amount of water to the amount of α -acetyl- γ -butyrolactone used is from 0.3 to 0.8: 1.
9. the production method according to claim 1, wherein, in the ring-opening reaction, the molar ratio of the amount of hydrochloric acid as HCl to the amount of α -acetyl- γ -butyrolactone is 1.5 to 2.5: 1.
10. the production method according to any one of claims 1 to 3, wherein the reaction time of the ring-opening reaction is 1 to 15 hours.
11. The production method according to claim 10, wherein the conditions of the ring-opening reaction include: the reaction temperature is 90-110 ℃, and the reaction time is 2-6 h.
12. The production method according to any one of claims 1 to 3, wherein the concentration of hydrochloric acid is 15 to 36% by weight.
13. The production process according to claim 1, wherein the dropping rate of hydrochloric acid as HCl is 2 to 4 mol/h.
14. The production method according to any one of claims 1 to 3, wherein the production method further comprises: after the ring-opening reaction is finished, separating the 3, 5-dichloro-2-pentanone from the reaction product.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3842029A1 (en) * | 1988-12-14 | 1990-06-21 | Basf Ag | 2-(3'-Halo-n-propyl)-2,5,7,8-tetramethyl-6-chromanols, process for their preparation, and intermediates of this process |
| CN103709023A (en) * | 2013-12-24 | 2014-04-09 | 秦永其 | Synthesis method for 3,5-dichloro-2-pentanone |
| CN104292089A (en) * | 2014-09-30 | 2015-01-21 | 大连九信生物化工科技有限公司 | Synthetic process of 1-chloro-cyclopropanecarbonyl chloride |
-
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3842029A1 (en) * | 1988-12-14 | 1990-06-21 | Basf Ag | 2-(3'-Halo-n-propyl)-2,5,7,8-tetramethyl-6-chromanols, process for their preparation, and intermediates of this process |
| CN103709023A (en) * | 2013-12-24 | 2014-04-09 | 秦永其 | Synthesis method for 3,5-dichloro-2-pentanone |
| CN104292089A (en) * | 2014-09-30 | 2015-01-21 | 大连九信生物化工科技有限公司 | Synthetic process of 1-chloro-cyclopropanecarbonyl chloride |
Non-Patent Citations (2)
| Title |
|---|
| 丙硫菌唑的合成工艺研究;张洪晓;《中国优秀硕士学位论文全文数据库 医药卫生科技辑》;20140915;第19页第3.2.2节 * |
| 高效安全杀菌剂丙硫菌唑的合成;徐欢;《中国优秀硕士学位论文全文数据库 工程科技Ⅰ辑》;20150215;第22页第2.2.1节，第23页第2.2.2.1节，第24页第2.3.1节、表2-1 * |
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