A new process preparation system and method for emamectin benzoate

Abstract

The present invention provides a novel process system and method for preparing emamectin benzoate. The system comprises a tubular reactor, wherein the bottom end of the tubular reactor is connected to a raw material mixing tank, one sidewall of the raw material mixing tank is connected to a raw material inlet, and the other sidewall of the raw material mixing tank is connected to a monomethylamine inlet. An external micro-interface unit is provided on the outside of the raw material mixing tank and is connected to the raw material inlet and the monomethylamine inlet, respectively. An internal micro-interface unit is provided on the inside of the raw material mixing tank, and the internal micro-interface unit is connected to the external micro-interface unit. The top end of the raw material mixing tank is connected to the tubular reactor to overflow the mixed material into the tubular reactor for reaction. The present invention utilizes a tubular reactor combined with micro-interface technology to mix monomethylamine gas with a raw material liquid to carry out an imidization reaction, thereby increasing the interfacial mass transfer area between the raw material and the monomethylamine gas, as well as the effective utilization rate of the monomethylamine and the reaction rate.

Description

Technical Field

[0001] The invention belongs to the technical field of emamectin benzoate preparation, and in particular to a new process preparation system and method for emamectin benzoate. Background Art

[0002] Emamectin benzoate is the full name of emamectin benzoate. It appears as a white or light yellow crystalline powder. It is soluble in acetone and methanol, slightly soluble in water, and insoluble in hexane. It is a new type of highly effective semi-synthetic antibiotic insecticide synthesized from the fermentation product avermectin B1. It has the characteristics of ultra-high efficiency, low toxicity (the preparation is nearly non-toxic), low residue, and pollution-free as a biological pesticide. It is widely used in the prevention and control of various pests on crops such as vegetables, fruit trees, and cotton.

[0003] The conventional production process for emamectin benzoate uses abamectin B1 as the starting material and proceeds through four steps: selective oxidation, selective amination, reduction, and salt formation to produce emamectin benzoate. Currently, the existing emamectin benzoate production process requires adding dichloromethane to a reactor, cooling it to 0°C, adding glacial acetic acid, and then dripping a 35% methylamino alcohol solution. After the addition is complete, the temperature is lowered to -15°C, and the oxidation product of abamectin is added. The reaction is allowed to proceed for 12 hours. After passing central control testing, the product undergoes reduction and crystallization to produce the emamectin benzoate product. The yield of the emamectin benzoate amination product is approximately 88%.

[0004] The existing technology has the following deficiencies:

[0005] (1) The yield of emamectin benzoate ammonium compound product is about 88% (calculated as the oxidation product of avermectin). After converting the methylamine alcohol solution into monomethylamine, the effective utilization rate of monomethylamine is about 8%. The consumption of solvents such as methanol, dichloromethane and glacial acetic acid is too high.

[0006] (2) The reaction time is as long as 12 hours, and the overall reaction efficiency is low.

[0007] (3) For every ton of emamectin benzoate imide produced, the imidization reaction generates 9.03 tons of reaction waste liquid, and the recovery cost is relatively high.

[0008] In view of this, the present invention is proposed. Summary of the Invention

[0009] A first object of the present invention is to provide a new process system for preparing emamectin benzoate. The system solves the problems of low effective utilization rate of monomethylamine and long reaction time in the prior art. A tubular reactor is used to control parameters such as temperature, pressure and flow rate of the emamectin benzoate preparation reaction to ensure the stability and consistency of the reaction process. Micro-interface technology is combined with the outside of the tubular reactor to fully crush and disperse the raw materials and monomethylamine, thereby increasing the interfacial mass transfer area between the raw materials and the monomethylamine gas, improving the effective utilization rate of monomethylamine, and increasing the reaction rate.

[0010] The second purpose of the present invention is to provide a new process for preparing emamectin benzoate using the above system. The method is simple to operate, has milder operating conditions, and low energy consumption, achieving a better treatment effect than the existing technology.

[0011] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are adopted:

[0012] The present invention provides a new process preparation system for emamectin benzoate, comprising a tubular reactor, wherein the bottom end of the tubular reactor is connected to a raw material mixing tank, one side wall of the raw material mixing tank is connected to a raw material inlet, the other side wall of the raw material mixing tank is connected to a monomethylamine inlet, an external micro-interface unit is provided outside the raw material mixing tank and is respectively connected to the raw material inlet and the monomethylamine inlet, an internal micro-interface unit is provided inside the raw material mixing tank, the internal micro-interface unit is connected to the external micro-interface unit, and the top end of the raw material mixing tank is connected to the tubular reactor to allow the mixed material to overflow into the tubular reactor for reaction.

[0013] In the prior art, the preparation of emamectin benzoate generally uses abamectin B1 as the starting material and obtains emamectin benzoate through a four-step reaction: selective oxidation, selective amination, reduction, and salt formation. However, in the selective amination step, the emamectin benzoate amination product is generally prepared using dichloromethane, glacial acetic acid, the avermectin oxidation product, and a methylamino alcohol solution. The reaction time is approximately 12 hours, and the reaction temperature is -15°C. These ultra-low temperature conditions increase reaction energy consumption, and the prolonged reaction time also leads to significant waste of resources. Furthermore, the selective amination reaction of the methylamino alcohol solution with the reaction materials is slow, resulting in an effective utilization rate of monomethylamine of approximately 8%, and excessive consumption of the solvents methanol, dichloromethane, and glacial acetic acid.

[0014] To address the above-mentioned technical problems, the present invention provides a novel process system for preparing emamectin benzoate. The system has a simple overall structure and utilizes monomethylamine gas instead of the methylamine alcohol solution used in the prior art. Direct reaction with the monomethylamine gas improves the reaction rate and the effective utilization rate of the monomethylamine. Furthermore, the system eliminates the need for methanol solvent, conserving energy and reducing energy consumption. By installing an external micro-interface unit outside the raw material mixing tank, the monomethylamine gas and raw materials are broken down and dispersed into micron-sized bubbles before mixing and contacting, increasing the gas-liquid mass transfer area between the reactants. Furthermore, by installing a built-in micro-interface unit inside the raw material mixing tank, the mixed materials entering the tank are mixed and stirred, improving reaction efficiency. The mixed materials are simultaneously broken down and dispersed, increasing the effective utilization rate of the monomethylamine and reducing reaction energy consumption.

[0015] Preferably, the built-in micro-interface unit is arranged at the bottom end of the raw material mixing tank, and the built-in micro-interface unit includes a first micro-interface generator and a second micro-interface generator. The first micro-interface generator is connected to the external micro-interface unit on the side of the monomethylamine inlet, and the second micro-interface generator is connected to the external micro-interface unit on the side of the raw material inlet.

[0016] Preferably, the outlets of the first micro-interface generator and the second micro-interface generator are opposite to each other.

[0017] Preferably, the external micro-interface unit is symmetrically arranged on both sides of the raw material mixing tank, and the external micro-interface unit includes a third micro-interface generator connected to the raw material inlet and a fourth micro-interface generator connected to the monomethylamine inlet, and the third micro-interface generator is arranged above the fourth micro-interface generator.

[0018] Preferably, the third micro-interface generator and the fourth micro-interface generator are connected via a pipeline.

[0019] Preferably, a stirring fan blade is provided inside the pipeline to circulate and stir the raw material liquid and monomethylamine gas in the external micro-interface unit.

[0020] Preferably, the tubular reactor is externally provided with a jacket barrel, and a side wall of the jacket barrel is provided with a coolant inlet for introducing coolant into the jacket barrel.

[0021] Preferably, a circulation pipe is provided outside the barrel, and a heat exchanger is provided in the middle of the circulation pipe for exchanging heat with the internal coolant.

[0022] In the present invention, the raw material liquid and monomethylamine gas are first introduced into a raw material mixing tank for mixing and stirring before entering the tubular reactor, which can ensure that the mixed materials entering the tubular reactor are mixed evenly, so that the reactants can fully contact and react.

[0023] The present invention provides an external micro-interface unit outside the raw material mixing tank, which can crush and disperse the monomethylamine gas and the raw material into micron-sized bubbles for mixing and contacting, thereby increasing the gas-liquid mass transfer area between the reactants; and by arranging a built-in micro-interface unit inside the raw material mixing tank, the mixed materials entering the raw material mixing tank are mixed and stirred, thereby improving the reaction efficiency, and at the same time, the mixed materials are crushed and dispersed, thereby improving the effective utilization rate of the monomethylamine and reducing the reaction energy consumption.

[0024] In the present invention, the built-in micro-interface unit is set at the bottom of the raw material mixing pool. The reason for setting it at the bottom is that the built-in micro-interface unit of the present invention can stir the liquid in the raw material mixing pool while achieving hedging. Specifically, the built-in micro-interface unit includes a first micro-interface generator and a second micro-interface generator. The outlets of the first micro-interface generator and the second micro-interface generator are opposite to each other. The two need to be combined into a whole and are not set separately. The two micro-interface generators are combined into a hybrid micro-interface unit, which improves the application effect of a separate micro-interface generator. On the one hand, a collision flow can be formed between the first micro-interface generator and the second micro-interface generator to further disperse and break the bubbles. On the other hand, when the interior of the first micro-interface generator is blocked, the bubble flow of the second micro-interface generator can be used to flush the interior of the first micro-interface generator to prevent blockage.

[0025] In the present invention, the external micro-interface unit includes a third micro-interface generator and a fourth micro-interface generator. The third micro-interface generator is positioned above the fourth micro-interface generator. The third micro-interface generator is fed with a raw liquid, while the fourth micro-interface generator is fed with monomethylamine gas. The two micro-interface generators are connected by a pipeline, which is also provided with stirring blades. As the raw liquid flows downward, the stirring blades rotate, drawing the monomethylamine gas and raw liquid from below the external micro-interface unit back toward the top, thereby increasing the monomethylamine gas content.

[0026] The monomethylamine gas enters the fourth micro-interface generator below the external micro-interface unit. The monomethylamine gas is broken and dispersed into monomethylamine microbubbles after passing through the fourth micro-interface generator. The monomethylamine microbubbles mix with the raw material liquid from bottom to top, increasing the interfacial mass transfer area between the raw material liquid and the monomethylamine gas. The stirring blades rotate to send the monomethylamine gas to the third micro-interface generator above the external micro-interface unit for micro-interface reaction again, breaking and dispersing the unreacted monomethylamine gas.

[0027] The new process preparation system of the present invention is further provided with a jacket barrel outside the tubular reactor, and a heat exchanger and a circulation pump are connected to the outside of the jacket barrel. The heat exchanger and the circulation pump circulate the coolant in the jacket barrel for heat exchange to ensure that the temperature of the coolant in the jacket barrel meets the reaction temperature.

[0028] The monomethylamine gas exiting the top of the tubular reactor of the present invention is returned to the raw material mixing tank through a pipeline. The purpose of this arrangement is to improve the recycling effect of the tail gas. The monomethylamine outlet at the top of the tubular reactor is connected to the monomethylamine inlet on the side wall of the raw material mixing tank. The monomethylamine in the tail gas is returned to the raw material mixing tank for further reaction, thereby improving the raw material utilization rate and saving costs.

[0029] Those skilled in the art will understand that the microinterface generator adopted in the present invention has been embodied in the inventor's prior patents, such as patents with application numbers CN201610641119.6, CN201610641251.7, CN201710766435.0, CN106187660, CN105903425A, CN109437390A, CN205833127U and CN207581700U. The prior patent CN201610641119.6 describes in detail the specific product structure and working principle of the micron bubble generator (i.e., microinterface generator). The application document states that "the micron bubble generator includes a main body and a secondary crushing member, the main body has a cavity, the main body is provided with an inlet connected to the cavity, the first and second opposite ends of the cavity are open, wherein the cross-sectional area of ​​the cavity decreases from the middle of the cavity toward the first and second ends of the cavity; the secondary crushing member is provided at at least one of the first and second ends of the cavity, a portion of the secondary crushing member is provided in the cavity, and an annular channel is formed between the secondary crushing member and the through holes open at both ends of the cavity. The micron bubble generator also includes an air inlet pipe and a liquid inlet pipe." From the specific structure disclosed in the application document, it can be known that its specific working principle is: liquid enters the micron bubble generator tangentially through the liquid inlet pipe, rotates at ultra-high speed and cuts the gas, causing the gas bubbles to break into micron-level microbubbles, thereby increasing the mass transfer area between the liquid phase and the gas phase, and the micron bubble generator in this patent is a pneumatic microinterface generator.

[0030] In addition, the prior patent 201610641251.7 records that the primary bubble breaker has a circulating liquid inlet, a circulating gas inlet and a gas-liquid mixture outlet, and the secondary bubble breaker connects the feed port with the gas-liquid mixture outlet, indicating that the bubble breaker requires a gas-liquid mixture to enter. In addition, it can be seen from the following figures that the primary bubble breaker mainly uses circulating liquid as power, so in fact the primary bubble breaker belongs to a hydraulic micro-interface generator, and the secondary bubble breaker simultaneously passes the gas-liquid mixture into an elliptical rotating ball for rotation, thereby achieving bubble breaking during the rotation process, so the secondary bubble breaker actually belongs to a gas-liquid linkage micro-interface generator. In fact, whether it is a hydraulic micro-interface generator or a gas-liquid linkage micro-interface generator, it is a specific form of micro-interface generator. However, the micro-interface generator adopted by the present invention is not limited to the above-mentioned forms. The specific structure of the bubble breaker recorded in the prior patent is only one of the forms that the micro-interface generator of the present invention can adopt.

[0031] In addition, the prior patent 201710766435.0 records that "the principle of the bubble breaker is a high-speed jet to achieve mutual collision of gases", and also explains that it can be used in a micro-interface enhanced reactor, verifying the correlation between the bubble breaker and the micro-interface generator itself; and the prior patent CN106187660 also has relevant records on the specific structure of the bubble breaker, see paragraphs

[0031] -

[0041] in the specification, and the drawings, which have a detailed explanation of the specific working principle of the bubble breaker S-2. The top of the bubble breaker is a liquid phase inlet, and the side is a gas phase inlet. The liquid phase entering from the top provides suction power, thereby achieving the effect of crushing into ultrafine bubbles. It can also be seen in the drawings that the bubble breaker has a conical structure, and the diameter of the upper part is larger than the diameter of the lower part, so that the liquid phase can better provide suction power.

[0032] Because the micro-interface generator was newly developed in the early stages of the prior patent application, it was initially named the micron bubble generator (CN201610641119.6) and the bubble breaker (201710766435.0). With continuous technological improvements, it was later renamed the micro-interface generator. The micro-interface generator in the present invention is equivalent to the previous micron bubble generator, bubble breaker, etc., only with a different name. In summary, the micro-interface generator of the present invention belongs to the prior art.

[0033] In addition, the present invention also provides a new process for preparing emamectin benzoate, comprising the following steps: mixing the raw material avermectin oxidation product, dichloromethane solution and glacial acetic acid solution with monomethylamine gas to undergo an imidization reaction, subsequently reducing and crystallizing the reaction product to form emamectin benzoate, and recovering the remaining monomethylamine gas for re-reaction.

[0034] Preferably, the imidization reaction temperature is -10 to 0°C, and the imidization reaction time is 5 to 8 hours.

[0035] Specifically, the imidization reaction temperature can be -9°C, -8°C, -7°C, -6°C, -5°C, -4°C, -3°C, -2°C and -1°C.

[0036] The preparation method of the present invention is simple to operate, can effectively improve the conversion rate of reactants and the yield of products, and at the same time, shortens the reaction time, increases the reaction temperature, and significantly reduces the cost.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] (1) The novel process preparation system of emamectin benzoate of the present invention adopts the combination of an internal micro-interface unit and an external micro-interface unit. The external micro-interface unit is used to crush and disperse the raw material liquid and monomethylamine gas, thereby increasing the interfacial area between the monomethylamine gas and the raw material liquid and improving the reaction efficiency. The internal micro-interface unit is used to achieve hedging, and at the same time, the mixed materials in the raw material mixing tank are stirred, thereby reducing the reaction time to 5 to 8 hours, increasing the reaction temperature to -10 to 0°C, and increasing the effective utilization rate of monomethylamine to more than 60%.

[0039] (2) By setting up a tubular reactor, the structure is compact and time is saved. By controlling the reaction parameters such as the temperature, pressure and flow rate of the tubular reactor, the stability and consistency of the reaction process are guaranteed, continuous production is achieved, and thus production efficiency is improved.

[0040] (3) By setting a jacket barrel outside the tubular reactor and using it in conjunction with a heat exchanger, a suitable reaction temperature is provided for the tubular reactor to increase the reaction rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present invention. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0042] Figure 1 A schematic structural diagram of a novel process for preparing emamectin benzoate provided in Example 1 of the present invention;

[0043] Figure 2 This is a schematic structural diagram of a new process preparation system for emamectin benzoate provided in Example 4 of the present invention.

[0044] in:

[0045] 1- Tubular reactor; 2- Raw material mixing tank;

[0046] 3- Import of raw materials; 4- Import of monomethylamine;

[0047] 5-Built-in micro-interface unit; 501-First micro-interface generator;

[0048] 502-second micro-interface generator; 6-external micro-interface unit;

[0049] 601-third micro-interface generator; 602-fourth micro-interface generator;

[0050] 603-mixing fan blade; 7-barrel set;

[0051] 8-Coolant inlet; 9-Heat exchanger;

[0052] 10-Monomethylamine storage tank; 11-Monomethylamine outlet. DETAILED DESCRIPTION

[0053] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. Those who do not specify specific conditions in the embodiments are carried out according to normal conditions or the conditions recommended by the manufacturer. Those whose reagents or instruments are not specified by the manufacturer are conventional products that can be purchased commercially.

[0054] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0055] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0056] In order to more clearly illustrate the technical solutions of the present invention, specific embodiments are provided below for illustration.

[0057] Example 1

[0058] See Figure 1As shown, a new process preparation system for emamectin benzoate according to an embodiment of the present invention includes a tubular reactor 1, the bottom end of the tubular reactor 1 is connected to a raw material mixing tank 2, a side wall of one side of the raw material mixing tank 2 is connected to a raw material inlet 3, and the other side wall of the raw material mixing tank 2 is connected to a monomethylamine inlet 4. An external micro-interface unit 6 is provided outside the raw material mixing tank 2 and is respectively connected to the raw material inlet 3 and the monomethylamine inlet 4. A built-in micro-interface unit 5 is provided inside the raw material mixing tank 2, and the built-in micro-interface unit 5 is connected to the external micro-interface unit 6. The top of the raw material mixing tank 2 is connected to the tubular reactor 1 to allow the mixed material to overflow into the tubular reactor 1 for reaction.

[0059] Specifically, the process flow of the present invention is to mix the raw materials of avermectin oxidation product, dichloromethane solution and glacial acetic acid solution with monomethylamine gas to undergo an imidization reaction. The reaction raw materials of the present invention include monomethylamine gas, so a tubular reactor 1 is used. After the monomethylamine gas and the raw material solution are introduced into the traditional reactor, the monomethylamine gas has a low density and therefore moves upward rapidly. As a result, the contact time between the monomethylamine gas and the raw material solution is shortened, and the effective utilization rate of the monomethylamine gas is low. The present invention uses a tubular reactor 1, which can, on the one hand, ensure efficient and stable reaction conditions. On the other hand, the tubular reactor 1 has a smaller volume and a larger surface area, so that the monomethylamine gas and the raw material solution can contact and react faster, thereby increasing the reaction rate. Preferably, the tubular reactor 1 of the present invention is a spiral ascending tubular reactor, which utilizes a rotating spiral structure to mix the raw material liquid and monomethylamine gas and transport them upward, so that the monomethylamine gas and the raw material liquid flow upward at the same time, allowing the reactants to fully contact and react, thereby improving the effective utilization rate of monomethylamine. This is something that the existing technology has not achieved under the premise of using methylamine alcohol liquid as the raw material.

[0060] Specifically, the bottom end of the tubular reactor 1 of the present invention is connected to the raw material mixing tank 2, and a built-in micro-interface unit 5 is provided inside the raw material mixing tank 2. The built-in micro-interface unit 5 crushes and disperses the mixed material entering the tubular reactor 1, thereby increasing the interfacial area of ​​the mixed material inside the tubular reactor 1, and at the same time fully contacts the mixed material inside the tubular reactor 1, thereby improving the reaction yield.

[0061] Specifically, the built-in micro-interface unit 5 of the present invention is arranged at the bottom of the raw material mixing tank 2. The built-in micro-interface unit 5 includes a first micro-interface generator 501 and a second micro-interface generator 502. The first micro-interface generator 501 is connected to the external micro-interface unit 6 on the side of the monomethylamine inlet 4, and the second micro-interface generator 502 is connected to the external micro-interface unit 6 on the side of the raw material inlet 3.

[0062] In this embodiment, the first micro-interface generator 501 and the second micro-interface generator 502 are arranged on the same straight line, and the outlets of the first micro-interface generator 501 and the second micro-interface generator 502 are opposite to each other. The monomethylamine gas raw liquid in the first micro-interface generator 501 and the monomethylamine gas and raw liquid in the second micro-interface generator 502 are offset, thereby increasing the interfacial mass transfer area and stirring the mixed materials in the raw material mixing tank 2 at the same time.

[0063] The external micro-interface unit 6 of the present invention is symmetrically arranged on both sides of the raw material mixing tank 2. The external micro-interface unit 6 includes a third micro-interface generator 601 connected to the raw material inlet 3 and a fourth micro-interface generator 602 connected to the monomethylamine inlet 4. The third micro-interface generator 601 is arranged above the fourth micro-interface generator 602. Preferably, the third micro-interface generator 601 and the fourth micro-interface generator 602 are connected by a pipeline. A stirring blade 603 is provided inside the pipeline to circulate and stir the raw material liquid and monomethylamine gas in the external micro-interface unit 6.

[0064] The present invention uses stirring blades 603 in conjunction with an external micro-interface unit 6. The stirring blades 603 are provided because the raw material for preparing emamectin benzoate in the present invention is monomethylamine gas, which has a relatively low density. A fourth micro-interface generator 602, connected to the monomethylamine inlet 4, is positioned below the external micro-interface unit 6. This allows the monomethylamine gas to be fragmented and dispersed by the fourth micro-interface generator 602, forming monomethylamine microbubbles. These bubbles then mix with the liquid raw material from bottom to top, increasing the interfacial area between the liquid raw material and the monomethylamine gas. The stirring blades 603 then rotate to transport the monomethylamine microbubbles to the third micro-interface generator 601 above the external micro-interface unit 6 for further micro-interface reaction, fragmenting and dispersing any unreacted monomethylamine gas. In the prior art, methylamino alcohol liquid is used as the reaction raw material. Because the methylamino alcohol liquid is liquid, it is relatively heavy after fragmentation and dispersion, making it difficult for the stirring blades 603 to transport it to the upper micro-interface generator for reaction. Consequently, no cyclic stirring is required. Therefore, the preparation system of the present invention is specifically provided with stirring blades for the reaction raw material monomethylamine gas of the present invention. As a result, the effective utilization rate of monomethylamine in the prior art is naturally not as high as that of the monomethylamine gas of the present invention.

[0065] In this embodiment, a jacket barrel 7 is provided on the outside of the tubular reactor 1 , and a coolant inlet 8 is provided on the side wall of the jacket barrel 7 for introducing coolant into the jacket barrel 7 to ensure that the reaction is in a low temperature environment.

[0066] Among them, a circulation pipe is provided outside the barrel 7, and a heat exchanger 9 is provided in the middle of the circulation pipe to exchange heat with the internal coolant. At the same time, a circulation pump is also provided on the circulation pipe to provide power for the circulating liquid;

[0067] The side wall of the barrel 7 is also provided with a coolant inlet 8 for introducing coolant into the barrel 7 .

[0068] In the embodiment of the present invention, the monomethylamine inlet 4 is connected to the monomethylamine storage tank 10 and the monomethylamine outlet 11 at the top of the tubular reactor 1 through a pipeline to recover unreacted monomethylamine gas in the tubular reactor 1 .

[0069] Specifically, a circulation pump is provided between the raw material inlet 3 and the raw material mixing tank 2 to provide power for the liquid raw material.

[0070] It can be understood that the number of micro-interface generators in the above embodiment is not limited. In order to increase the dispersion and mass transfer effects, additional micro-interface generators can also be added.

[0071] During the specific reaction, the raw materials, avermectin oxidation product, dichloromethane solution, glacial acetic acid solution and monomethylamine gas in the monomethylamine storage tank 10, are crushed and dispersed by the external micro-interface unit 6, and then introduced into the first micro-interface generator 501 and the second micro-interface generator 502 inside the raw material mixing tank 2 for secondary crushing and dispersion; the mixed material formed after the first micro-interface generator 501 and the second micro-interface generator 502 are offset, enters the tubular reactor 1 by overflow to carry out imidization reaction, the reaction temperature is -5°C, and the reaction product is subsequently reduced and crystallized to form emamectin benzoate.

[0072] Example 2

[0073] This embodiment differs from embodiment 1 only in the reaction temperature, which is 0°C.

[0074] Example 3

[0075] This embodiment differs from embodiment 1 only in the reaction temperature, which is -10°C.

[0076] Example 4

[0077] The difference between this embodiment and embodiment 3 is that the outlet of the first micro-interface generator of the built-in micro-interface unit and the outlet of the second micro-interface generator are not on the same straight line. Figure 2 shown.

[0078] Comparative Example 1

[0079] The difference between this embodiment and embodiment 3 is that a built-in micro-interface unit is not provided.

[0080] Comparative Example 2

[0081] The difference between this embodiment and embodiment 3 is that no external micro-interface unit is provided.

[0082] Comparative Example 3

[0083] This example adopts the existing technology, directly adding dichloromethane into the reactor, cooling to 0°C, adding glacial acetic acid, and adding 35% methylamino alcohol solution dropwise. After the addition is completed, the temperature is lowered to minus 15°C, and the oxidation product of avermectin is added to carry out the imidization reaction. The reaction product enters the subsequent reduction crystallization process to generate the emamectin benzoate product.

[0084] Experimental Example 1

[0085] Emamectin benzoate was prepared by the preparation systems of Examples 1-4 and Comparative Example 1, wherein the feed rate of avermectin oxidation product was 1026 kg / batch, the feed rate of monomethylamine was 66 kg / batch, and the feed rate of 28.3 m 3 / batch, dichloromethane feed rate 6800kg / batch, reaction liquid circulation rate 20m 3 / h, the reaction pressure is 0.1MPa. The reaction results are shown in the following table:

[0086] Table 1

[0087]

[0088]

[0089] As can be seen from Table 1, Example 3 of the present invention is the best embodiment. The reaction temperature of the preparation system of this embodiment is significantly higher than the reaction temperature of preparing emamectin benzoate in the prior art, and the reaction time is significantly shortened, while still achieving good raw material conversion rate and product yield. At the same time, the effective utilization rate of monomethylamine is significantly improved. It can be seen that the preparation system of this embodiment has low reaction energy consumption and good preparation effect.

[0090] Among them, the effective utilization rate of monomethylamine in Comparative Example 1 is lower than that in Example 3. This is because Comparative Example 1 does not have a built-in micro-interface unit, which cannot crush and disperse the raw materials inside the raw material mixing tank, and cannot stir the mixed materials inside the raw material mixing tank. It can be seen that this embodiment improves the effective utilization rate of monomethylamine by setting the arrangement of the micro-interface generator in the raw material mixing tank.

[0091] In summary, compared with the prior art, the new process for preparing emamectin benzoate of the present invention has the advantages of easy realization of reaction temperature, short reaction time, high raw material conversion rate and high product yield, and is worthy of wide promotion and application.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, 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 invention.

Claims

1. A new process preparation system for emamectin benzoate, characterized in that, The invention comprises a tubular reactor, wherein the bottom end of the tubular reactor is connected to a raw material mixing tank, one side wall of the raw material mixing tank is connected to a raw material inlet, the other side wall of the raw material mixing tank is connected to a monomethylamine inlet, an external micro-interface unit is provided on the outside of the raw material mixing tank and is respectively connected to the raw material inlet and the monomethylamine inlet, an internal micro-interface unit is provided on the inside of the raw material mixing tank, the internal micro-interface unit is connected to the external micro-interface unit, and the top end of the raw material mixing tank is connected to the tubular reactor to allow the mixed material to overflow into the tubular reactor for reaction; The built-in micro-interface unit is arranged at the bottom of the raw material mixing tank, and the built-in micro-interface unit includes a first micro-interface generator and a second micro-interface generator. The first micro-interface generator is connected to the external micro-interface unit on the side of the monomethylamine inlet, and the second micro-interface generator is connected to the external micro-interface unit on the side of the raw material inlet; The external micro-interface unit is symmetrically arranged on both sides of the raw material mixing tank, and the external micro-interface unit includes a third micro-interface generator connected to the raw material inlet and a fourth micro-interface generator connected to the monomethylamine inlet, and the third micro-interface generator is arranged above the fourth micro-interface generator; The tubular reactor is externally sheathed with a barrel, and a side wall of the barrel is provided with a coolant inlet for introducing coolant into the barrel.

2. the novel process preparation system of emamectin benzoate according to claim 1, is characterized in that, The outlets of the first micro-interface generator and the second micro-interface generator are opposite to each other.

3. the novel process preparation system of emamectin benzoate according to claim 1, is characterized in that, The third micro-interface generator and the fourth micro-interface generator are connected via a pipeline.

4. the novel process preparation system of emamectin benzoate according to claim 3, is characterized in that, The pipeline is provided with stirring blades for circulating and stirring the raw material liquid and monomethylamine gas in the external micro-interface unit.

5. the novel process preparation system of emamectin benzoate according to claim 1, is characterized in that, A circulation pipe is provided outside the barrel, and a heat exchanger is provided in the middle of the circulation pipe for exchanging heat with the internal coolant.

6. adopt the preparation method of the novel process preparation system of the described emamectin benzoate of any one of claim 1-5, it is characterized in that, The steps include: The raw material avermectin oxidation product, dichloromethane solution and glacial acetic acid solution are mixed with monomethylamine gas to undergo imidization reaction, and the reaction product is subsequently reduced and crystallized to form emamectin benzoate, and the remaining monomethylamine gas is recovered and reacted again.

7. The preparation method of emamectin benzoate according to claim 6, wherein The imidization reaction temperature is -10 to 0° C., and the imidization reaction time is 5 to 8 hours.

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