A process for the preparation of 6-ethylthio-3-hepten-2-one

Abstract

The present application relates to the technical field of chemical synthesis, especially to IPC C07C323, more particularly to a method for preparing 6-ethylsulfanyl-3-heptene-2-ketone, which comprises the following steps: mixing 3-ethylsulfanyl butyraldehyde, water and a catalyst, adding dropwise divinyl ketone at 25-35 DEG C, keeping warm for 7-10 hours, adding acid to dehydrate, washing with alkali after the reaction is completed, and vacuum desolventizing to obtain 6-ethylsulfanyl-3-heptene-2-ketone. The present application uses 3-ethylsulfanyl butyraldehyde, divinyl ketone, a catalyst and water as raw materials, has low energy consumption, and will not produce wastewater containing sodium acetate, methanol and acetone.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chemical synthesis, in particular to IPC C07C323, more particularly to a method for preparing 6-ethylsulfanyl-3-hepten-2-one. BACKGROUND

[0002] Oxadiazon is a new type of post-emergence herbicide for dry field, which can prevent and remove annual and perennial grass weeds, and has excellent selectivity. 6-ethylsulfanyl-3-hepten-2-one is an important pesticide and pharmaceutical intermediate, which is often used in the synthesis of cyclohexenone herbicides.

[0003] In the traditional method, 6-ethylsulfanyl-3-hepten-2-one is synthesized by mixing aqueous sodium acetoacetate and toluene, then adjusting the pH value with acetic acid, and finally adding 3-ethylsulfanylbutyraldehyde dropwise, incubating, washing with water, and desolubilizing to obtain 6-ethylsulfanyl-3-hepten-2-one. Sodium acetoacetate is unstable and must be prepared by reacting methyl acetoacetate or ethyl acetoacetate with liquid caustic soda when used, and a large amount of wastewater containing sodium acetate, methanol and acetone and other substances is generated. This wastewater cannot be directly treated by biochemical treatment, but must be treated by a series of treatments, which not only has high energy consumption, but also produces hazardous waste such as sodium acetate trihydrate. Therefore, there is a problem that acetoacetate must be prepared for the preparation of heptenone, which has high energy consumption, complex wastewater composition and difficult treatment.

[0004] The existing patent CN202211058649.X discloses a preparation method and composition of acetoacetate, 6-ethylsulfanyl-3-hepten-2-one and intermediates thereof. The method is simple in operation, mild in reaction condition, high in atomic utilization rate, high in overall yield and good in purity. However, the method uses a hydration catalyst selected from a specific catalyst of palladium, nickel or rhodium, which has high cost. SUMMARY

[0005] In order to solve the problems in the prior art, the first aspect of the present application provides a method for preparing 6-ethylsulfanyl-3-hepten-2-one, which is:

[0006] In a four-necked flask, toluene, 3-ethylsulfanylbutyraldehyde, water and a catalyst are added, and divinyl ketone is added dropwise at 25-35℃, incubated for 7-10h, then dehydrated with acid, washed with alkali after the reaction is completed, and vacuum desolubilized to obtain 6-ethylsulfanyl-3-hepten-2-one.

[0007] The reaction equation of the present application is as follows:

[0008]

[0009]

[0010] Preferably, the molar ratio of the 3-ethylsulfanylbutyraldehyde to the diketene is 1: (1.05-1.10); more preferably, 1:1.05.

[0011] Preferably, the mass ratio of the water to the diketene is (22-25):100; more preferably, (22-23):100.

[0012] In a preferred embodiment, the mass ratio of the water to the diketene is 22.65:100.

[0013] Preferably, the catalyst is an organic alkaline catalyst.

[0014] Preferably, the organic alkaline catalyst comprises one or more of triethylamine, piperidine, 4-dimethylaminopyridine, pyridine, diisopropylethylamine; more preferably, triethylamine, piperidine, 4-dimethylaminopyridine or pyridine.

[0015] Preferably, the mass ratio of the catalyst to the diketene is (0.5-10):100; more preferably, (0.5-3):100.

[0016] In a preferred embodiment, the mass ratio of the catalyst to the diketene is 1:100.

[0017] Preferably, the temperature of the heat preservation reaction is 30-110℃; more preferably, 30, 70 or 110℃.

[0018] Preferably, the acid is sulfuric acid, phosphoric acid.

[0019] Preferably, the sulfuric acid is a 95-98wt% aqueous solution of sulfuric acid; more preferably, a 98wt% aqueous solution of sulfuric acid.

[0020] Preferably, the mass ratio of the acid to the diketene is 0.004-0.015:1

[0021] Preferably, the solution used in the alkali washing is an alkaline solution.

[0022] Preferably, the alkaline solution is one or more of an aqueous solution of sodium hydroxide, an aqueous solution of sodium carbonate, an aqueous solution of sodium bicarbonate, an aqueous solution of potassium hydroxide; more preferably, an aqueous solution of sodium hydroxide, an aqueous solution of sodium carbonate or an aqueous solution of sodium bicarbonate.

[0023] Preferably, the mass concentration of the solute of the alkaline solution is 0.1%-0.2%.

[0024] Preferably, the temperature of the alkali washing is 30-50℃.

[0025] Preferably, the pressure of the vacuum desolventizing is -0.095 to -0.098 MPa.

[0026] Preferably, the temperature of the vacuum desolventizing is 55 to 75 DEG C.

[0027] Preferably, the 3-ethylthio butyraldehyde CAS number is 27205-24-9.

[0028] Preferably, the diketene CAS number is 674-82-8.

[0029] The present application selects diketene to replace sodium acetylacetate prepared by methyl acetoacetate or ethyl acetoacetate and liquid caustic soda, which can reduce solid waste and energy loss, reduce harmful substance generation, and improve yield. The present inventors accidentally found that adding diketene in the preparation of 6-ethylthio-3-heptene-2-ketone can avoid on-site preparation of sodium acetylacetate, which is unstable and prepared by reaction of methyl acetoacetate or ethyl acetoacetate with liquid caustic soda, and can generate a large amount of wastewater containing sodium acetate, methanol and acetone, etc. The wastewater treatment needs to consume a large amount of energy, and can also generate hazardous waste such as sodium acetate trihydrate. Selecting diketene and 3-ethylthio butyraldehyde to react under the action of water and catalyst can avoid subsequent wastewater treatment. On the other hand, selecting sodium acetylacetate needs to use acetic acid to adjust pH in the experimental process, which is more complex, and the intermediate product can reduce the subsequent yield. Replacing with diketene only needs to weigh diketene, which simplifies the operation steps, avoids the generation of too many intermediate products, and thus improves the yield. In addition, the preparation of sodium acetylacetate by reaction of methyl acetoacetate or ethyl acetoacetate with liquid caustic soda, and then adjusting pH and reacting with 3-ethylthio butyraldehyde, needs water washing in the post-treatment process. Using the scheme in the present application, alkali washing is adopted in the water washing process, and the amount of water and alkali used is greatly reduced compared with the reaction of sodium acetylacetate. When treating the wastewater in the present application, the wastewater does not need to be evaporated to remove salt, which reduces the generation of solid waste and energy consumption.

[0030] In the present application, the mass ratio of water to diketene is controlled to be (22-25):100, which can improve the yield of the product. The present inventors accidentally found that controlling the mass ratio of water and diketene, adding toluene, 3-ethylthio butyraldehyde, water, catalyst, and then adding diketene dropwise at 25-35 DEG C for 7-10 h of heat preservation reaction can obtain 6-ethylthio-3-heptene-2-ketone with high purity and high yield, which does not need metal catalyst, reduces production cost, simplifies steps, and improves yield. Controlling the mass ratio of water and diketene can synthesize a large amount of 6-ethylthio-4-hydroxy-2-ketone before dehydration reaction.

[0031] Advantages

[0032] 1. This invention uses diketene instead of sodium acetoacetate prepared by reacting methyl acetoacetate or ethyl acetoacetate with liquid alkali, which can reduce solid waste and energy consumption, and improve yield while reducing the generation of harmful substances. In this invention, diketene undergoes a weakly reversible reaction with water to produce acetoacetic acid. Acetoacetic acid then undergoes an irreversible reaction with thioether aldehyde under the action of a catalyst. The continuous progress of the subsequent reaction promotes the continuous progress of the preceding reaction, until the final reaction is completely completed.

[0033] 2. This invention employs specific organic alkaline catalysts—triethylamine, piperidine, 4-dimethylaminopyridine, and pyridine—and controls the mass ratio of catalyst to diketene to be (0.5–3):100, which accelerates the reaction rate. Even without a metal catalyst, it increases the yield of the intermediate 6-ethylthio-4-hydroxy-2-one. After dehydration, a high yield of 6-ethylthio-3-hepten-2-one is obtained, further improving the product yield. Simultaneously, the organic alkaline catalyst is effective, recyclable, and reduces costs. In this system, using an inorganic alkaline catalyst requires the addition of acetic acid, easily forming sodium acetate wastewater, which is detrimental to industrial production. Furthermore, the organic alkaline catalyst used in this invention produces wastewater free of metal elements, which can be biochemically treated.

[0034] 3. In this invention, controlling the mass ratio of water to diketene to be (22-25):100 can improve the yield of the product.

[0035] 4. This invention uses diketene instead of sodium acetoacetate to react with 3-ethylthiobutyraldehyde in the presence of water and a catalyst. The reaction temperature is controlled at 30–110°C, and the reaction time is 7–10 hours to ensure maximum reaction of the raw materials and minimize raw material loss. After the reaction, alkaline washing is performed using an alkaline solution. The temperature of the alkaline washing and the concentration range of the solute in the alkaline solution are controlled to dissolve impurities in the aqueous phase and 6-ethylthio-3-hepten-2-one in the toluene phase, thereby separating and purifying 6-ethylthio-3-hepten-2-one. This simplifies the operation steps. Setting the vacuum desolvation temperature at 55°C–75°C and the pressure at -0.095–-0.098 MPa yields a large amount of 6-ethylthio-3-hepten-2-one with minimal loss.

[0036] 5. In this invention, toluene, 3-ethylthiobutyraldehyde, water, and catalyst are directly added, and diketene is added dropwise at 25–35°C for a sustained reaction. This eliminates the need for step-by-step reactions, simplifying the reaction process. Simultaneously, by directly controlling the mass ratios of water and diketene, as well as the catalyst and diketene, the yield of the intermediate product 6-ethylthio-4-hydroxy-2-one is increased, thereby controlling the yield and purity of the final product. The absence of a metal catalyst also reduces costs. Detailed Implementation

[0037] Example 1

[0038] In a 250 mL four-necked flask, 50 mL of toluene, 13.22 g of 3-ethylthio butyraldehyde, 2.00 g of water and 0.10 g of piperidine were added, 8.83 g of divinyl ketone was added dropwise at 30°C, and the mixture was stirred at 30°C for 10 h, then 0.045 g of 98% wt% sulfuric acid aqueous solution was added for dehydration, after the reaction was completed, 20 g of 0.1% sodium hydroxide aqueous solution was added at 30°C, and the mixture was stirred, allowed to stand, the lower layer of waste water was separated, and the toluene phase was desolventized at -0.095 MPa to 75°C to obtain 6-ethylthio-3-heptene-2-one.

[0039] Example 2

[0040] In a 250 mL four-necked flask, 50 mL of toluene, 13.22 g of 3-ethylthio butyraldehyde, 2.00 g of water and 0.10 g of piperidine were added, 8.83 g of divinyl ketone was added dropwise at 30°C, and the mixture was stirred at 30°C for 7 h, then 0.045 g of 98% wt% sulfuric acid aqueous solution was added for dehydration, after the reaction was completed, 20 g of 0.1% sodium hydroxide aqueous solution was added at 30°C, and the mixture was stirred, allowed to stand, the lower layer of waste water was separated, and the toluene phase was desolventized at -0.098 MPa to 55°C to obtain 6-ethylthio-3-heptene-2-one.

[0041] Example 3

[0042] In a 250 mL four-necked flask, 50 mL of toluene, 13.22 g of 3-ethylthio butyraldehyde, 2.00 g of water and 0.10 g of piperidine were added, 8.83 g of divinyl ketone was added dropwise at 30°C, and the mixture was stirred at 70°C for 10 h, then 0.045 g of 98% wt% sulfuric acid aqueous solution was added for dehydration, after the reaction was completed, 20 g of 0.1% sodium hydroxide aqueous solution was added at 50°C, and the mixture was stirred, allowed to stand, the lower layer of waste water was separated, and the toluene phase was desolventized at -0.097 MPa to 65°C to obtain 6-ethylthio-3-heptene-2-one.

[0043] Example 4

[0044] In a 250 mL four-necked flask, 50 mL of toluene, 13.22 g of 3-ethylthio butyraldehyde, 2.00 g of water and 0.10 g of piperidine were added, 8.83 g of divinyl ketone was added dropwise at 30°C, and the mixture was stirred at 70°C for 7 h, then 0.045 g of 98% wt% sulfuric acid aqueous solution was added for dehydration, after the reaction was completed, 10 g of 0.2% sodium hydroxide aqueous solution was added at 40°C, and the mixture was stirred, allowed to stand, the lower layer of waste water was separated, and the toluene phase was desolventized at -0.097 MPa to 65°C to obtain 6-ethylthio-3-heptene-2-one.

[0045] Example 5

[0046] In a 250 mL four-necked flask, 50 mL of toluene, 13.22 g of 3-ethylthiobutyraldehyde, 2.00 g of water and 0.10 g of piperidine were added, 8.83 g of divinyl ketone was added dropwise at 30°C, and the mixture was kept at 110°C for 7 h, then 0.045 g of 98%wt aqueous sulfuric acid was added for dehydration, after the reaction was completed, 10 g of 0.2%wt sodium carbonate aqueous solution was added at 40°C, the mixture was stirred, allowed to stand, the lower layer of waste water was separated off, and the toluene phase was desolventized at -0.097 MPa to 65°C to obtain 6-ethylthio-3-heptene-2-one.

[0047] Example 6

[0048] In a 250 mL four-necked flask, 50 mL of toluene, 13.22 g of 3-ethylthiobutyraldehyde, 2.00 g of water and 0.10 g of piperidine were added, 8.83 g of divinyl ketone was added dropwise at 30°C, and the mixture was kept at 110°C for 7 h, then 0.045 g of 98%wt aqueous sulfuric acid was added for dehydration, after the reaction was completed, 10 g of 0.2%wt sodium carbonate aqueous solution was added at 40°C, the mixture was stirred, allowed to stand, the lower layer of waste water was separated off, and the toluene phase was desolventized at -0.097 MPa to 65°C to obtain 6-ethylthio-3-heptene-2-one.

[0049] Example 7

[0050] In a 250 mL four-necked flask, 50 mL of toluene, 13.22 g of 3-ethylthiobutyraldehyde, 2.00 g of water and 0.10 g of piperidine were added, 8.83 g of divinyl ketone was added dropwise at 30°C, and the mixture was kept at 110°C for 7 h, then 0.045 g of 98%wt aqueous sulfuric acid was added for dehydration, after the reaction was completed, 10 g of 0.2%wt sodium carbonate aqueous solution was added at 40°C, the mixture was stirred, allowed to stand, the lower layer of waste water was separated off, and the toluene phase was desolventized at -0.097 MPa to 65°C to obtain 6-ethylthio-3-heptene-2-one.

[0051] Comparative Example 1

[0052] The specific implementation of Comparative Example 1 is the same as that of Example 1, except that the catalyst is 11.5%wt aqueous sodium hydroxide solution.

[0053] Comparative Example 2

[0054] The specific implementation of Comparative Example 2 is the same as that of Example 1, except that no catalyst is used in the method.

[0055] Comparative Example 3

[0056] The specific implementation of Comparative Example 3 is the same as that of Example 1, except that 0.69 g of potassium tetrachloropalladate is additionally added in the scheme.

[0057] Comparative Example 4

[0058] The detailed implementation of Comparative Example 4 is the same as that of Example 1, except that the mass ratio of water to divinyl ketone is 78:100.

[0059] Comparative Example 5

[0060] The detailed implementation of Comparative Example 5 is the same as that of Example 1, except that the mass ratio of catalyst to divinyl ketone is 10:100.

[0061] Performance Test

[0062] 1. The 6-ethylsulfanyl-3-hepten-2-one obtained in Examples 1-5 was weighed using a weighing balance, and the results are recorded in Table 1.

[0063] 2. The purity of the 6-ethylsulfanyl-3-hepten-2-one obtained in Examples 1-5 was determined using HPLC, and the results are recorded in Table 1.

[0064] 3. The yield was calculated = (mass * purity) / theoretical mass.

[0065] Table 1

[0066] mass purity yield example 1 17.2g 95％ 95％ example 2 17.4g 93％ 94％ example 3 17.4g 94％ 95％ example 4 17.4g 93％ 94％ example 5 17.3g 94％ 94％ example 6 17.4g 93％ 94％ example 7 17.4g 93％ 94％ comparative example 1 21.2 0.8％ 1％ comparative example 2 21.2 0.8％ 1％ comparative example 3 21.2 94％ 95％ comparative example 4 19.1 45％ 50％ comparative example 5 17.6 93％ 95％

Claims

1. A process for the preparation of 6-ethylsulfanyl-3-hepten-2-one, characterized in that, The method is: In a four-port flask, toluene, 3-ethylthio butyraldehyde, water, catalyst are mixed, and then dimethyl ketone is added dropwise at 25-35 DEG C, and the reaction is kept for 7-10 hours, then acid is added for dehydration, after the reaction is completed, the product is washed with alkali, and then vacuum desolventized to obtain 6-ethylthio-3-heptene-2-ketone; The reaction equation is as follows: The catalyst is an organic alkaline catalyst; the organic alkaline catalyst comprises one or more of triethylamine, piperidine, 4-dimethylaminopyridine, pyridine, and diisopropylethylamine.

2. The process for the preparation of 6-ethylsulfanyl-3-hepten-2-one according to claim 1, characterized in that, The molar ratio of 3-ethylthio butyraldehyde to dimethyl ketone is 1:(1.05-1.10).

3. The method of claim 1, wherein the 6-ethylsulfanyl-3-hepten-2-one is produced by the reaction of 6-ethylsulfanyl-3-hepten-2-ol with a base. The mass ratio of water to dimethyl ketone is (22-25):

100.

4. The method for preparing 6-ethylthio-3-hepten-2-one according to claim 1, characterized in that, The mass ratio of the catalyst to dimethyl ketone is (0.5-10):

100.

5. The method for preparing 6-ethylthio-3-hepten-2-one according to claim 1, characterized in that, The temperature of the reaction is 30-110 DEG C.

6. The method for preparing 6-ethylthio-3-hepten-2-one according to claim 1, characterized in that, The acid is sulfuric acid or phosphoric acid.

7. The process for the preparation of 6-ethylsulfanyl-3-hepten-2-one according to claim 1, characterized in that, The alkali washing solution is an alkaline solution; the alkaline solution is one or more of sodium hydroxide aqueous solution, sodium carbonate aqueous solution, sodium bicarbonate aqueous solution, and potassium hydroxide aqueous solution.

8. The method of producing 6-ethylsulfanyl-3-hepten-2-one according to claim 7, characterized in that, The mass concentration of the solute of the alkaline solution is 0.1%-0.2%.

9. The method for preparing 6-ethylthio-3-hepten-2-one according to claim 1, characterized in that, The temperature of the alkali washing is 30-50 DEG C.

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