Method for continuously preparing 6-ethylthio-3-heptene-2-ketone

Abstract

The invention relates to a method for continuously preparing 6-ethylthio-3-heptene-2-ketone. The method comprises the following steps: (1) metering and conveying a mixed solution of toluene, 3-ethylthiobutyraldehyde, water and piperidine and diketene to a first feed storage tank and a second feed storage tank respectively; (2) simultaneously conveying the mixed solution of toluene, 3-ethylthiobutyraldehyde, water and piperidine and diketene into a tubular reactor by adopting a regulating valve and a flow meter for reaction; and (3) the reaction liquid flows out of the outlet of the tubular reactor to an intermediate tank, then enters a dehydration kettle to be dehydrated by adding acid, and is transferred into an alkali washing kettle for alkali washing and a desolventizing kettle for vacuum desolventizing to obtain the 6-ethylthio-3-heptene-2-ketone product. The method is reasonable in design, capable of achieving continuous production, efficient in reaction, capable of shortening the production period and safer.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for continuously preparing 6-ethylsulfanyl-3-hepten-2-one. BACKGROUND

[0002] Oxadiazon is a post-emergence herbicide with excellent selectivity for use in broadleaf fields such as soybeans, rapeseed, cotton, peanuts, etc. to control annual and perennial grass weeds such as barnyard grass, hard grass, etc. 6-ethylsulfanyl-3-hepten-2-one is an important intermediate for pesticides and medicines, which is used for the synthesis of oxadiazon. The main synthesis process of 6-ethylsulfanyl-3-hepten-2-one at present is to use 3-ethylsulfanylbutyraldehyde as the main raw material, and sodium acetoacetate to obtain through Claisen condensation reaction.

[0003] In the traditional synthesis method, sodium acetoacetate aqueous solution and toluene are mixed, then acetic acid is used to adjust the pH value, and finally 3-ethylsulfanylbutyraldehyde is added dropwise, incubated, washed with water, and desolventized to obtain 6-ethylsulfanyl-3-hepten-2-one. The reaction selectivity and yield are high, but the operation is complex and the three wastes are significant.

[0004] The scheme disclosed in Chinese Patent Publication No. CN114957060A is to use 3-ethylsulfanylbutyraldehyde and acetone as raw materials, and under the conditions of solvent and catalyst, a mixture containing 6-ethylsulfanyl-3-hepten-2-one is obtained; then filtering, solvent distillation to obtain the desired product 6-ethylsulfanyl-3-hepten-2-one. In this scheme, 3-ethylsulfanylbutyraldehyde and acetone are added in the form of a mixed solution, which increases the operation difficulty; the product yield and purity are not high, which increases the production cost.

[0005] The scheme disclosed in Chinese Patent Publication No. CN116751145A is to use 3-ethylsulfanylbutyraldehyde and divinyl ketone as raw materials, and under the conditions of solvent and catalyst, after reaction, acid is added to dehydrate to obtain a mixture containing 6-ethylsulfanyl-3-hepten-2-one; then alkaline washing, vacuum desolventizing to obtain the desired product 6-ethylsulfanyl-3-hepten-2-one. This scheme uses a kettle type batch process for production, which has long production cycle and low production efficiency; low degree of automation, and high labor intensity of operators. SUMMARY

[0006] The present application improves the above-mentioned prior art, that is, the technical problem to be solved by the present application is to provide a method for continuously preparing 6-ethylsulfanyl-3-hepten-2-one.

[0007] In order to achieve the above object, the technical scheme adopted by the present application is: a method for continuously preparing 6-ethylsulfanyl-3-heptene-2-ketone, comprising the following steps: (1) metering and conveying a toluene, 3-ethylsulfanyl butyraldehyde, water and piperidine mixed solution and divinyl ketone into a first feed storage tank and a second feed storage tank respectively; (2) simultaneously conveying the toluene, 3-ethylsulfanyl butyraldehyde, water and piperidine mixed solution and divinyl ketone into a tubular reactor for reaction by using a regulating valve and a flow meter; (3) flowing the reaction liquid from the outlet of the tubular reactor into an intermediate tank, and then into a dehydration kettle for acid dehydration, an alkali washing kettle for alkali washing and a desolventizing kettle for vacuum desolventizing to obtain a 6-ethylsulfanyl-3-heptene-2-ketone product.

[0008] Further, in step (1), the toluene, 3-ethylsulfanyl butyraldehyde, water and piperidine are respectively pumped into the first feed storage tank by a metering pump, and the materials in the first feed storage tank are circulated by an external circulation pump to obtain a mixed solution.

[0009] Further, in step (1), the mass ratio of the 3-ethylsulfanyl butyraldehyde, water and piperidine is 100:(14-17):(0.5-4).

[0010] Further, in step (1), the molar ratio of the 3-ethylsulfanyl butyraldehyde and the divinyl ketone is 1:(1.02-1.07).

[0011] Further, in step (2), the flow rate of the toluene, 3-ethylsulfanyl butyraldehyde, water and piperidine mixed solution into the tubular reactor is 1174-1190 kg / h.

[0012] Further, in step (2), the flow rate of the divinyl ketone into the tubular reactor is 176-186 kg / h.

[0013] Further, in step (2), the flow pressure of the toluene, 3-ethylsulfanyl butyraldehyde, water and piperidine mixed solution and the divinyl ketone in the tubular reactor is 1.0-3.0 Mpa.

[0014] Further, in step (2), the reaction temperature of the tubular reactor is 30-50℃, and the residence time of the materials in the tubular reactor is 200-800 seconds.

[0015] Further, in step (3), the reaction materials flowing out from the outlet of the tubular reactor are acidified by adding 98% sulfuric acid, and then are transferred into an alkali washing kettle to wash the layers by adding 30% sodium hydroxide liquid, and then are desolventized to obtain a 6-ethylsulfanyl-3-heptene-2-ketone product.

[0016] Further, in step (3), the toluene obtained by desolventizing is used in step (1) for preparing the mixed solution.

[0017] Compared with the prior art, the application has the following effects: the application is reasonable in design, continuous production can be realized, the reaction is efficient, the production cycle is shortened, and safety is improved. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is the reaction formula of the application. DETAILED DESCRIPTION

[0019] The application will be further described in detail below in combination with the drawings and specific embodiments.

[0020] In the description of the application, it should be understood that the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the application, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application.

[0021] As shown in Figure 1 The application is a method for continuously preparing 6-ethylsulfanyl-3-hepten-2-one with high efficiency, which is suitable for industrial production and has high yield, and the method comprises the following steps: (1) measuring and conveying a toluene, 3-ethylsulfanylbutyraldehyde, water and piperidine mixed solution and a divinyl ketone into a first feed storage tank and a second feed storage tank, respectively; (2) conveying the toluene, 3-ethylsulfanylbutyraldehyde, water and piperidine mixed solution and the divinyl ketone into a tubular reactor at a certain flow rate for reaction by using a regulating valve and a flow meter; and (3) flowing the reaction liquid from the outlet of the tubular reactor into an intermediate tank, and then into a dehydrating kettle for acid dehydration, an alkali washing kettle for alkali washing and a desolventizing kettle for vacuum desolventizing to obtain a 6-ethylsulfanyl-3-hepten-2-one product.

[0022] Specifically, in step (1), the toluene, 3-ethylsulfanylbutyraldehyde, water and piperidine are respectively pumped into the first feed storage tank by a metering pump, and the materials in the first feed storage tank are circulated by an external circulation pump to obtain a mixed solution.

[0023] Specifically, in step (1), the mass ratio of 3-ethylsulfanylbutyraldehyde, water and piperidine is 100:(14-17):(0.5-4), and the optimal mass ratio of 3-ethylsulfanylbutyraldehyde, water and piperidine is 100:14:1.

[0024] Specifically, in step (1), the molar ratio of 3-ethylthiobutyraldehyde and divinyl ketone is 1: (1.02-1.07), and the optimal molar ratio of 3-ethylthiobutyraldehyde and divinyl ketone is 1:1.03.

[0025] Specifically, in step (2), the flow rate of the mixed solution of toluene, 3-ethylthiobutyraldehyde, water and piperidine into the tubular reactor is 1174-1190 kg / h. The flow rate of divinyl ketone into the tubular reactor is 176-186 kg / h. The flow rates of the two materials are adjusted according to the above ratio, and the optimal flow rate of the mixed solution into the tubular reactor is 1180 kg / h, and the optimal flow rate of divinyl ketone into the tubular reactor is 181 kg / h.

[0026] Specifically, in step (2), the flow pressure of the mixed solution of toluene, 3-ethylthiobutyraldehyde, water and piperidine and divinyl ketone in the tubular reactor is 1.0-3.0 MPa, and the optimal flow pressure is 1.5-2.5 MPa.

[0027] Specifically, in step (2), the reaction temperature of the tubular reactor is 30-50℃, and the residence time of the material in the tubular reactor is 200-800 seconds. The tubular reactor is a U-shaped tubular reactor with a diameter of DN100-500 mm and a length of 100-500 meters.

[0028] Specifically, in step (3), the reaction material flowing out from the outlet of the tubular reactor is acidified by adding 98% sulfuric acid, and then transferred into an alkali washing kettle to wash the layer by adding 30% sodium hydroxide liquid alkali, and then desolventized to obtain 6-ethylthio-3-heptene-2-ketone product. Further, the toluene obtained by desolventization is used in step (1) to prepare the mixed solution.

[0029] Example 1 Toluene, 3-ethylthiobutyraldehyde, water and piperidine were respectively pumped into the first feed tank by the metering pump according to the mass ratio of 3-ethylthiobutyraldehyde, water and piperidine of 100:14:0.5, and the material was circulated by the first feed tank external circulation pump to obtain a mixed solution. The mixed solution and divinyl ketone were respectively pumped into a DN100 mm, 300 meter long U-shaped tubular reactor by adjusting the valve and flow meter according to the flow rate of 1174 kg / h, 176 kg / h, the reaction temperature was 30-40℃, the residence time was 500-600 seconds, and the flow pressure was 1.0-2.0 MPa. After the reaction was completed, the reaction material flowed out from the outlet of the U-shaped tubular reactor into an acidification kettle, and then 98% sulfuric acid was added for acidification, and the material was transferred into an alkali washing kettle, and then 30% liquid alkali was added to adjust the pH to 7-7.5 for alkali washing and layering. After the organic phase was reduced pressure desolventized, the product 6-ethylthio-3-heptene-2-ketone was obtained, with a purity of 97.0% and a yield of 96.5%.

[0030] Example 2 Toluene, 3-ethylthiobutyraldehyde, water and piperidine were respectively pumped into the first feed tank by the metering pump according to the mass ratio of 3-ethylthiobutyraldehyde, water and piperidine of 100:17:4, and the mixed solution was obtained by circulating the material through the external circulation pump of the first feed tank. The mixed solution and divinyl ketone were respectively pumped into the DN100mm, 300m long U-shaped tubular reactor through the regulating valve and flow meter according to the flow rate of 1185kg / h, 180kg / h, the reaction temperature was 40-50℃, the residence time was 400-500 seconds, and the flow pressure was 2.0-3.0MPa. After the reaction was completed, the reaction material flowed out from the outlet of the U-shaped tubular reactor into the acidification kettle, an appropriate amount of 98% sulfuric acid was added for acidification, the material was transferred into the alkali washing kettle, 30% liquid alkali was added to adjust the pH to 7-7.5 for alkali washing and layering, and after the organic phase was removed under reduced pressure, the product 6-ethylthio-3-heptene-2-ketone was obtained, with a purity of 98.0% and a yield of 97.5%.

[0031] Example 3 Toluene, 3-ethylthiobutyraldehyde, water and piperidine were respectively pumped into the first feed tank by the metering pump according to the mass ratio of 3-ethylthiobutyraldehyde, water and piperidine of 100:17:4, and the mixed solution was obtained by circulating the material through the external circulation pump of the first feed tank. The mixed solution and divinyl ketone were respectively pumped into the DN100mm, 300m long U-shaped tubular reactor through the regulating valve and flow meter according to the flow rate of 1185kg / h, 180kg / h, the reaction temperature was 40-50℃, the residence time was 400-500 seconds, and the flow pressure was 2.0-3.0MPa. After the reaction was completed, the reaction material flowed out from the outlet of the U-shaped tubular reactor into the acidification kettle, an appropriate amount of 98% sulfuric acid was added for acidification, the material was transferred into the alkali washing kettle, 30% liquid alkali was added to adjust the pH to 7-7.5 for alkali washing and layering, and after the organic phase was removed under reduced pressure, the product 6-ethylthio-3-heptene-2-ketone was obtained, with a purity of 98.0% and a yield of 97.5%.

[0032] The advantages of the present application are: (1) The tubular reactor can realize precise control of the reaction process, the average residence time is 200-800 seconds, which is greatly reduced compared with the 7 hours of the batch process, and the reaction efficiency is improved; (2) The continuous production process does not require dripping, which improves the degree of automation and the safety coefficient of operation.

[0033] If the present application discloses or relates to mutually fixedly connected parts or structural members, unless otherwise stated, the fixed connection can be understood as: detachably fixedly connected (for example, connected using bolts or screws), and can also be understood as: non-detachable fixed connection (for example, riveting, welding), of course, the mutually fixed connection can also be replaced by an integral structure (for example, manufactured by integral forming using a casting process) (obviously, integral forming process cannot be used).

[0034] In addition, the terms used to represent the positional relationship or shape in any of the technical solutions disclosed in the present application include states or shapes similar, similar or close to them, unless otherwise stated.

[0035] Any component provided by the present application can be assembled from multiple individual components, or can be a single component manufactured by integral forming process.

[0036] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application and not to limit them; although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the specific embodiments of the present application can be modified or some technical features can be replaced by equivalents; without departing from the spirit of the technical solutions of the present application, they should be included in the technical solution range of the present application claimed.

Claims

1. A process for the continuous production of 6-ethylsulfanyl-3-hepten-2-one, characterized in that: The method comprises the following steps: (1) metering and conveying toluene, 3-ethylthio butyraldehyde, water and piperidine mixed solution and divinyl ketone into first and second feed storage tanks respectively; (2) simultaneously conveying toluene, 3-ethylthio butyraldehyde, water and piperidine mixed solution and divinyl ketone into a tubular reactor for reaction by using regulating valves and flow meters; (3) flowing the reaction liquid from the outlet of the tubular reactor into an intermediate tank, and then into a dehydrating kettle for acid dehydration, an alkali washing kettle for alkali washing and a desolventizing kettle for vacuum desolventizing to obtain 6-ethylthio-3-heptene-2-ketone product.

2. A process for the continuous production of 6-ethylsulfanyl-3-hepten-2-one according to claim 1, characterized in that: In step (1), toluene, 3-ethylthio butyraldehyde, water and piperidine are respectively pumped into the first feed storage tank by metering pumps, and the materials in the first feed storage tank are circulated by an external circulation pump to obtain the mixed solution.

3. A process for the continuous production of 6-ethylsulfanyl-3-hepten-2-one according to claim 1, characterized in that: In step (1), the mass ratio of 3-ethylthio butyraldehyde, water and piperidine is 100:(14-17):(0.5-4).

4. A process for the continuous production of 6-ethylsulfanyl-3-hepten-2-one according to claim 1, characterized in that: In step (1), the molar ratio of 3-ethylthio butyraldehyde to divinyl ketone is 1:(1.02-1.07).

5. A process for the continuous production of 6-ethylsulfanyl-3-hepten-2-one according to claim 1, characterized in that: In step (2), the flow rate of the toluene, 3-ethylthio butyraldehyde, water and piperidine mixed solution into the tubular reactor is 1174-1190 kg / h.

6. A process for the continuous production of 6-ethylsulfanyl-3-hepten-2-one according to claim 1, characterized in that: In step (2), the flow rate of divinyl ketone into the tubular reactor is 176-186 kg / h.

7. A process for the continuous production of 6-ethylsulfanyl-3-hepten-2-one according to claim 1, characterized in that: In step (2), the flow pressure of the toluene, 3-ethylthio butyraldehyde, water and piperidine mixed solution and divinyl ketone in the tubular reactor is 1.0-3.0 MPa.

8. A process for the continuous production of 6-ethylsulfanyl-3-hepten-2-one according to claim 1, characterized in that: In step (2), the reaction temperature of the tubular reactor is 30-50℃, and the residence time of the materials in the tubular reactor is 200-800 seconds.

9. The process for the continuous production of 6-ethylsulfanyl-3-hepten-2-one according to claim 1, characterized in that: In step (3), the reaction materials flowing out from the outlet of the tubular reactor are acidified by adding 98% sulfuric acid, and then transferred into an alkali washing kettle for alkali washing by adding 30% sodium hydroxide liquid, and then desolventized to obtain 6-ethylthio-3-heptene-2-ketone product.

10. The process for the continuous production of 6-ethylsulfanyl-3-hepten-2-one according to claim 1, characterized in that: In step (3), the toluene obtained by desolventizing is used in step (1) for preparing the mixed solution.

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