A preparation device and preparation method of methyl anthranilate

Abstract

The present application provides a device and method for preparing methyl anthranilate. The device for preparing methyl anthranilate includes a Hofmann degradation reaction component, a heating reaction component, and an esterification reaction component. The Hofmann degradation reaction component includes a first jet loop reactor, in which a methanol solution, a sodium hypochlorite solution, and an aqueous sodium o-formamidobenzoate solution undergo a Hofmann degradation reaction under jet mixing and cooling; the heating reaction component includes a kettle-type stirred reactor, in which sodium sulfite is added to react with an excess of sodium hypochlorite solution; and the esterification reaction component includes a second jet loop reactor, in which methyl anthranilate is generated under jet mixing and heating. The present application designs the three stages of the intermittent production process of methyl anthranilate to be carried out in three specific reactors, thereby reducing the total production time. The Hofmann degradation reaction component and the esterification reaction component use jet loop reactors, which are conducive to enhancing mass transfer and heat transfer and increasing the reaction rate.

Description

Technical Field

[0001] The present application relates to the field of chemical process technology, and in particular to a device and method for preparing methyl anthranilate. Background Art

[0002] Methyl anthranilate is a colorless to pale yellow liquid or crystals with blue fluorescence at room temperature, with an odor of grape or orange. It is chemically stable, but it tends to discolor upon prolonged exposure to light. Methyl anthranilate is readily soluble in ethanol and ether, with its ethanol solution exhibiting blue fluorescence. It is soluble in most fixed oils and propylene glycol, slightly soluble in water, and insoluble in glycerin. Its boiling point is between 256 and 260°C, its liquid density is 1.168 g / mL, its flash point is 123°C, and its melting point is 24 to 25°C. Methyl anthranilate is an intermediate in saccharin production, and its yield significantly impacts the production and quality of saccharin sodium. Methyl anthranilate is a pale yellow or colorless liquid at room temperature with a rich fruity and floral aroma. It is an important chemical raw material used in the fine chemical, pharmaceutical, cosmetic, and food industries.

[0003] Methods for synthesizing methyl anthranilate include the direct anthranilate esterification method, the o-nitrobenzoic acid method, the phthalic anhydride urea method, the microbial degradation method, and the phthalic anhydride ammonia method. The direct anthranilate esterification method uses sulfuric acid as a catalyst to directly react methanol with anthranilate to produce methyl anthranilate. This process is simple and easy to operate, but it consumes large amounts of acid and methanol, resulting in low yields. The reactant, anthranilate, is chemically active and difficult to store, making this method unsuitable for industrial production. The o-nitrobenzoic acid method involves an esterification reaction to produce methyl anthranilate, followed by catalytic hydrogenation reduction to produce methyl anthranilate. This method uses expensive o-nitrobenzoic acid, has low yields, and is not economically viable. The phthalic anhydride-urea method is essentially the same as the phthalic anhydride-ammonia method, differing primarily in that urea is used instead of the pungent ammonia. The phthalic anhydride and urea react in a molten state, improving environmental performance. However, phthalic anhydride has a melting point of 131°C, while urea has a melting point of 132.7°C. Urea is thermally unstable and deaminates to biuret when heated to 150-160°C. It then decomposes at 160°C, producing ammonia gas and isocyanic acid. This narrow reaction temperature range makes it difficult to control the actual reaction temperature, hindering large-scale industrial production. The microbial degradation method utilizes microbial enzymes to convert anthranilic acid to methyl anthranilate in a 10% methanol environment. However, methanol denatures proteins, resulting in a maximum yield of 10%, and the biocatalyst is expensive. The raw materials for the phthalic anhydride-ammonia method include phthalic anhydride, methanol, ammonia, sodium hydroxide, and sodium hypochlorite. Ammonia water and phthalic anhydride are mixed and stirred. When the solution begins to heat up, sodium hydroxide solution is added to keep the solution alkaline. The reaction is carried out at a constant temperature for a period of time. After the reaction is completed, the reaction solution is passed into an ammonia removal tower to remove ammonia to obtain an amidation solution. The pre-cooled amidation solution is mixed with sodium hypochlorite solution, and a Hofmann degradation reaction occurs under a low temperature environment. After the low-temperature reaction is completed, an appropriate amount of sodium bisulfite solution is added until the starch potassium iodide solution test solution no longer changes color. Methanol is then introduced for esterification. After the reaction is completed, the solution is allowed to stand and separate. The lower layer solution obtained by extraction is methyl anthranilate. The advantage of this process is that the raw material phthalic anhydride is low in cost and easy to store, making it suitable for large-scale industrial production. However, since this process is intermittently operated by workers, the operating parameters rely on the workers' experience, resulting in unstable product quality. At the same time, there are prominent problems such as high safety and environmental pressure, high labor costs, and low intermittent production efficiency. Therefore, finding a more green and environmentally friendly continuous process route is of great significance for shortening the production cycle and reducing energy consumption and raw material consumption. Summary of the Invention

[0004] The present application provides a preparation device and a preparation method for methyl anthranilate, which solves the problem of low efficiency in the current preparation of methyl anthranilate.

[0005] According to the preparation device of methyl anthranilate in the first embodiment of the present application, it includes:

[0006] A Hofmann degradation reaction component comprises a first jet loop reactor, a circulating cooling pump and a sodium hypochlorite feed pump, wherein the circulating cooling pump and the sodium hypochlorite feed pump are respectively connected to the jet loop reactor;

[0007] A heating reaction component, the heating reaction component includes a kettle-type stirring reactor;

[0008] The esterification reaction component includes a second jet loop reactor and a water feed pump, the water feed pump is connected to the second jet loop reactor, and the esterification reaction component is connected to the Hofmann degradation reaction component through a heating reaction component.

[0009] Optionally, in other embodiments of the present application, the first jet loop reactor and the second jet loop reactor respectively include an ejector, a reactor, a circulation pump, a heat exchanger, a flow detector, a pressure detector and a temperature detector.

[0010] Optionally, in other embodiments of the present application, the stirring blade of the kettle-type stirred reactor is a paddle-type stirring blade or a turbine-type stirring blade.

[0011] Optionally, in other embodiments of the present application, the heat exchanger includes a shell and tube heat exchanger.

[0012] Optionally, in other embodiments of the present application, the ejector includes a nozzle, a suction chamber, a mixing chamber, and a diffusion chamber.

[0013] Optionally, in other embodiments of the present application, the flow detector includes an electromagnetic flowmeter.

[0014] According to the preparation method of methyl anthranilate in the second embodiment of the present application, the preparation is carried out using the above-mentioned preparation device, and the preparation method includes:

[0015] Providing pre-cooled methanol solution, sodium hypochlorite solution and sodium o-formamidobenzoate aqueous solution;

[0016] In the Hofmann degradation reaction component, a methanol solution and an aqueous solution of sodium o-formamidobenzoate are added to a first jet loop reactor, and a circulation pump and a circulation cooling pump in the Hofmann degradation reaction component are started to circulate and mix;

[0017] Starting the sodium hypochlorite feed pump, adding the sodium hypochlorite solution into the first jet loop reactor, causing a first reaction after circulation and mixing, and transporting the reacted first reaction liquid to the heating reaction assembly;

[0018] Sodium sulfite is added to the stirred tank reactor to undergo a second reaction with an excess of sodium hypochlorite solution, and the second reaction liquid after the reaction is transported to the esterification reaction component;

[0019] The circulation pump and heat exchanger in the esterification reaction assembly are started, the water feed pump is started, water is added to the second jet loop reactor, circulated and mixed, and a third reaction is carried out to obtain a third reaction liquid.

[0020] Optionally, in other embodiments of the present application, the pre-cooling temperature is -20°C to 0°C.

[0021] Optionally, in other embodiments of the present application, the volume ratio of the sodium o-formamidobenzoate aqueous solution to the methanol solution is 1:(0.5-1.5).

[0022] Optionally, in other embodiments of the present application, the volume ratio of the sodium hypochlorite solution to the methanol solution is in the range of (0.75-1.80):1.

[0023] Optionally, in other embodiments of the present application, the concentration of available chlorine in the sodium hypochlorite solution is 7.5% to 16%.

[0024] Optionally, in other embodiments of the present application, the concentration of methanol in the methanol solution is 75% to 100%.

[0025] Optionally, in other embodiments of the present application, the temperature of the first reaction is -20°C to 20°C, the temperature of the second reaction is 20°C to 30°C, and the temperature of the third reaction is 40°C to 80°C.

[0026] Optionally, in other embodiments of the present application, the time for the first reaction is 10 min to 50 min, the time for the second reaction is 10 min to 30 min, and the time for the third reaction is 10 min to 50 min.

[0027] Optionally, in other embodiments of the present application, the preparation method further comprises: allowing the third reaction liquid to stand, separating and extracting to obtain methyl anthranilate.

[0028] The device for preparing methyl anthranilate according to the embodiment of the present application has at least the following technical effects:

[0029] 1) The Hofman degradation reaction assembly of the present application includes a first jet loop reactor, and the esterification reaction assembly includes a second jet loop reactor. The use of the jet loop reactor is beneficial for enhancing mass and heat transfer, increasing the reaction rate, avoiding local overheating and local excess of reactants, inhibiting side reactions, and improving the selectivity of the reaction;

[0030] 2) The preparation device of the present application includes a Hofmann degradation reaction component, a heating reaction component and an esterification reaction component. Each reaction component has a simple structure, low manufacturing cost and maintenance cost, high operational flexibility, and is easy to scale up and industrially produce continuously. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 Schematic diagram of a device for preparing methyl anthranilate provided in one embodiment of the present application;

[0033] Figure 2 Schematic diagram of a jet loop reactor provided in one embodiment of the present application;

[0034] Figure 3 Schematic diagram of the preparation method of methyl anthranilate provided in one embodiment of the present application.

[0035] The symbols in the figure are: 1-Hofman reaction component, 11-first jet loop reactor, 111-ejector, 112-reactor, 113-circulation pump, 114-heat exchanger, 115-detector, 12-circulation cooling pump, 13-sodium hypochlorite feed pump, 2-heating reaction component, 21-kettle stirred reactor, 3-esterification reaction component, 31-second jet loop reactor, 32-water feed pump. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present application, and are not used to limit the present application. In the present application, unless otherwise specified, the directional words used, such as "up", "down", "left", and "right", generally refer to the up, down, left, and right of the device in actual use or working state, specifically the drawing direction in the accompanying drawings.

[0037] The present invention provides a device and method for preparing methyl anthranilate. The following are detailed descriptions of the following embodiments. It should be noted that the order in which the following embodiments are described does not limit the preferred order of the embodiments.

[0038] See also Figure 1The embodiment of the present application provides a preparation device for methyl anthranilate, comprising: a Hofmann degradation reaction component 1, wherein the Hofmann degradation reaction component 1 includes a first jet loop reactor 11, a circulating cooling pump 12, and a sodium hypochlorite feed pump 13, and the circulating cooling pump 12 and the sodium hypochlorite feed pump 13 are respectively connected to the jet loop reactor; a heating reaction component 2, wherein the heating reaction component 2 includes a kettle stirred reactor 21; an esterification reaction component 3, wherein the esterification reaction component 3 includes a second jet loop reactor 31 and a water feed pump 32, and the water feed pump 32 is connected to the second jet loop reactor 31, and the esterification reaction component 3 is connected to the Hofmann degradation reaction component 1 through the heating reaction component 2. The Hofmann degradation reaction assembly 1 includes a first jet loop reactor 11, and the esterification reaction assembly 3 includes a second jet loop reactor 31. The jet loop reactor has a simple structure, high operational flexibility, good sealing, and can enhance mass transfer and heat transfer, which is conducive to the continuity of the process and the scale-up of the reactor. It can solve the problem of slow mass transfer and heat transfer during the reaction of a mixed solution of sodium hypochlorite solution with a methanol solution and an aqueous solution of sodium o-formamidobenzoate in the Hofmann reaction stage.

[0039] See also Figure 2 The first jet loop reactor 11 and the second jet loop reactor 31 respectively include an ejector 111, a reactor 112, a circulation pump 113, a heat exchanger 114 and a detector 115.

[0040] In some embodiments of the present application, the detector 115 includes one or more of a flow detector, a pressure detector, or a temperature detector to detect various reaction parameters.

[0041] In some embodiments of the present application, the stirring blade of the kettle-type stirred reactor 21 is a paddle-type stirring blade or a turbine-type stirring blade.

[0042] In some embodiments of the present application, the reactor 112 of the first jet loop reactor 11 adopts a reactor wall jacket or a coiled tube arranged inside the reactor for heat exchange, the reactor 112 of the second jet loop reactor 31 adopts electric heating, electric heating or hot steam, and the heat exchanger 114 includes a shell and tube heat exchanger.

[0043] In some embodiments of the present application, the ejector 111 includes a nozzle, a suction chamber, a mixing chamber, and a diffusion chamber. The circulating liquid ejected from the nozzle is mixed with the sodium hypochlorite entering the suction chamber in the suction chamber, the mixing chamber, and the diffusion chamber.

[0044] Furthermore, the flow detector includes an electromagnetic flowmeter.

[0045] Furthermore, the circulation pump 113 is used to circulate the material.

[0046] Specifically, the pipes through which sodium hypochlorite flows are made of oxidation-resistant and corrosion-resistant materials such as polypropylene (PP), polytetrafluoroethylene, and Hastelloy, and the remaining pipes and the reactor 112 are made of 304 stainless steel.

[0047] See also Figure 3 The present invention also provides a method for preparing methyl anthranilate, which is prepared using the above-mentioned preparation device. The preparation method comprises:

[0048] Step S1: providing a pre-cooled methanol solution, a sodium hypochlorite solution and an aqueous solution of sodium o-formamidobenzoate (amidation solution);

[0049] Step S2: In the Hofmann degradation reaction component 1, the methanol solution and the sodium o-formamidobenzoate aqueous solution are added to the first jet loop reactor 11, and the circulation pump 113 and the circulation cooling pump 12 in the Hofmann degradation reaction component 1 are started to circulate and mix;

[0050] Step S3: starting the sodium hypochlorite feed pump 13, adding the sodium hypochlorite solution into the first jet loop reactor 11, causing a first reaction after circulation and mixing, and transporting the first reaction liquid after the reaction to the heating reaction assembly 2;

[0051] Step S4: adding sodium sulfite to the stirred tank reactor 21 to undergo a second reaction with an excess of sodium hypochlorite solution, and transporting the second reaction liquid after the reaction to the esterification reaction assembly 3;

[0052] Step S5: start the circulation pump 113 and the heat exchanger 114 in the esterification reaction assembly 3, start the water feed pump 32, add water into the second jet loop reactor 31, circulate and mix, and obtain a third reaction liquid after a third reaction occurs.

[0053] The present application designs the three stages of the intermittent production process of methyl anthranilate to be carried out in three specific reactors, thereby reducing the total production time, improving production efficiency, and effectively reducing labor costs. It solves the problems of unstable product quality, low intermittent production efficiency, high labor costs, and high safety and environmental protection pressures in existing processes. For example, the use of tubular reactors is not conducive to continuous production, and the use of microchannel reactors is small in scale. It provides a design that is easy to scale up and for continuous industrial production, and the mass fraction of the obtained methyl anthranilate is greater than 99%.

[0054] In some embodiments of the present application, the pre-cooling temperature can be -20°C to 0°C, or -15°C to -5°C, or -10°C to -8°C. If the cooling temperature is too low, the reaction rate will decrease, which is not conducive to the reaction. If the cooling temperature is too high, it will be difficult to cool the reaction liquid quickly, which will cause an increase in side reactions and a decrease in product yield. When the cooling temperature is within the range, the cooling effect is good, the side reactions are few, and the product yield is high.

[0055] In some embodiments of the present application, the volume ratio of the aqueous solution of sodium o-formamidobenzoate to the methanol solution can be 1:(0.5-1.5), or 1:(0.8-1.2), or 1:1. If the volume ratio of the aqueous solution of sodium o-formamidobenzoate to methanol is too small, it is easy to cause local shortage of methanol in the reaction solution, increasing the occurrence of side reactions. If the volume ratio is too large, it will cause waste of methanol. The volume ratio within the said range can ensure sufficient methanol consumption without causing waste of raw material methanol.

[0056] In some embodiments of the present application, the volume ratio of the sodium hypochlorite solution to the sodium o-formamidobenzoate aqueous solution can be in the range of (0.75-1.80):1, or (1.0-1.5):1, or (1.2-1.3):1. The volume ratio of the sodium hypochlorite solution to the sodium o-formamidobenzoate aqueous solution is the reaction condition that has the greatest impact on the product yield. Increasing the volume ratio can increase the product yield, but if the volume ratio is too large, it will cause excessive sodium hypochlorite and excessive oxidation of the sodium o-formamidobenzoate. The volume ratio within the said range can ensure the normal synthesis of the product.

[0057] In some embodiments of the present application, the concentration of available chlorine in the sodium hypochlorite solution can be 7.5% to 16%, or 10% to 15%, or 11% to 13%. If the concentration of available chlorine is too low, the reaction rate will decrease, the amount of sodium hypochlorite used will increase, and the reactor volume will increase. If the concentration of available chlorine is too high, it will easily cause the local concentration of sodium hypochlorite in the reactor to be too high, increasing the occurrence of side reactions. The concentration of available chlorine within the above range can ensure a high yield of the product.

[0058] In some embodiments of the present application, the concentration of methanol in the methanol solution can be 75% to 100%, or 80% to 95%, or 85% to 90%. The methanol actually used in the reaction is excessive. In order to meet the requirements of environmental protection and saving raw materials, methanol is often recovered by distillation and reused. The recovered methanol contains some water, and the actual concentration of methanol is 75% to 100%. The water contained in the methanol solution within the said range will not have a great impact on the product yield, and can be used directly or after refined treatment.

[0059] In some embodiments of the present application, the temperature of the first reaction can be -20°C to 20°C, or -10°C to 10°C, or -5°C to 5°C; the temperature of the second reaction can be 20°C to 30°C, or 22°C to 28°C, or 23°C to 25°C; the temperature of the third reaction can be 40°C to 80°C, or 50°C to 70°C, or 55°C to 60°C. The temperature of the first reaction is affected by both the cooling temperature and the exothermic heat of reaction. If the temperature is too low, the reaction rate will decrease, which is not conducive to the reaction. If the temperature is too high, it will be difficult to cool the reaction solution quickly, which will increase the side reaction and reduce the product yield. The temperature of the second reaction is the transition between the first reaction temperature and the third reaction temperature. The temperature is between the two reaction temperatures. The appropriate increase in temperature allows the unreacted material at the first reaction temperature to continue to react and ensures that the temperature is not too high to cause the generation of side reactions.

[0060] In some embodiments of the present application, the time of the first reaction can be 10min~50min, or 20min~40min, or 30min~35min; the time of the second reaction can be 10min~30min, or 15min~25min, or 20min~23min; the time of the third reaction can be 10min~50min, or 20min~40min, or 30min~35min. If the reaction time is too short during the reaction, the reaction is incomplete and the product yield is low. If the reaction time is too long, the product yield will not be significantly improved, but the economic cost will increase. The reaction time can ensure complete reaction and high product yield within the range.

[0061] Optionally, in other embodiments of the present application, the preparation method further comprises: allowing the third reaction liquid to stand, separating the liquids, and extracting to separate and obtain methyl anthranilate. Specifically, the obtained third reaction liquid is allowed to stand, and the liquids are separated. The lower oil phase is methyl anthranilate of higher purity, and the upper aqueous phase is extracted with an extractant, and the liquids are separated and distilled to recover the methyl anthranilate in the aqueous phase. Propionic acid is selected as an internal standard, and the purity and yield of methyl anthranilate are analyzed by gas chromatography.

[0062] Furthermore, the extractant includes one or more of toluene, o-xylene, m-xylene and p-xylene.

[0063] Furthermore, the gas chromatography analysis detector is a hydrogen flame detector (FID), the chromatographic column model is a capillary column, the chromatographic column length is 30m, the chromatographic column outer diameter is 0.32mm, the chromatographic column thickness is 0.25μm, the vaporization chamber temperature is 250℃, the detector temperature is 250℃, the air injection rate is 300mL / min, the hydrogen injection rate is 30mL / min, the carrier gas is nitrogen, the nitrogen injection rate is 20mL / min, the injection volume is 0.6μL, and the heating program is an initial temperature of 60℃, maintained for 0min, heated to 220℃ at a heating rate of 25℃ / min, and then maintained for 4min.

[0064] During specific implementation, the preparation method of methyl anthranilate comprises:

[0065] 1) pre-cooling the methanol solution, sodium hypochlorite solution, and sodium o-formamidobenzoate aqueous solution to a certain temperature;

[0066] 2) Adding methanol solution and sodium o-formamidobenzoate aqueous solution to the first jet loop reactor 11 of the Hofmann degradation reaction assembly 1, starting the circulation pump 113 and the circulation cooling pump 12, adjusting the circulation flow rate through the pump outlet valve, and circulating mixing for 5 minutes;

[0067] 3) starting the sodium hypochlorite feed pump 13 to continuously deliver the sodium hypochlorite solution to the ejection fluid inlet of the first jet loop reactor 11, where the solution is circulated and mixed and undergoes a first reaction in the first jet loop reactor 11. After the reaction is complete, the first reaction liquid is discharged into the heating reaction assembly 2;

[0068] 4) In the stirred tank reactor 21, sodium sulfite is added under stirring to reduce the unreacted sodium hypochlorite solution in the Hofmann degradation reaction stage. After the second reaction is completed, the second reaction liquid is discharged into the esterification reaction assembly 3;

[0069] 5) After the materials are added to the esterification reaction assembly 3, the circulation pump 113 and the heating device are started. After the circulation flow stabilizes, the water feed pump 32 is started to continuously deliver water to the ejector fluid inlet of the second jet loop reactor 31. Water is circulated and mixed in the jet loop reactor and the third reaction is carried out. After the reaction is completed, the third reaction liquid is discharged;

[0070] 6) After standing, the liquid is separated. The main component of the lower oil phase is the target product methyl anthranilate, propionic acid is selected as the internal standard, and the product purity is detected by gas chromatography. The upper aqueous phase is extracted with an extractant, and the product methyl anthranilate is obtained after liquid separation and distillation.

[0071] The following describes the details in conjunction with specific embodiments.

[0072] Example 1

[0073] 1) The sodium hypochlorite solution, methanol solution, and amidation solution were cooled to -10°C in advance. The cooling temperature of the first jet loop reactor 11 was set to -10°C, the temperature of the stirred tank reactor 21 was set to 30°C, and the temperature of the second jet loop reactor 31 was set to 60°C;

[0074] 2) First, add 200 ml of methanol solution and 200 ml of amidation liquid into the first jet loop reactor 11 and circulate and mix for 5 minutes;

[0075] 3) After the circulating flow rate, temperature, and pressure stabilize, the sodium hypochlorite feed pump 13 is started to continuously deliver 350 ml of sodium hypochlorite solution to the ejector fluid inlet of the ejector 111 within 30 minutes. The sodium hypochlorite solution enters the suction chamber from the ejector fluid inlet, passes through the suction chamber, mixing chamber, and diffusion chamber in sequence to complete primary mixing. The material is continuously circulated by the circulating pump 113 and passes through the ejector 111 multiple times to complete mixing.

[0076] 4) Open the outlet valve to introduce the first reaction liquid from the Hofmann degradation reaction component 1 into the heating reaction component 2, add 4 g of sodium sulfite to the stirred tank reactor 21, and stir the reaction at 30° C. for 10 minutes;

[0077] 5) Open the outlet valve to introduce the second reaction liquid from the heating reaction component 2 into the esterification reaction component 3 to carry out the esterification reaction. The materials are circulated and mixed in the esterification reactor for 10 minutes;

[0078] 6) After the reaction is completed, the product obtained in the esterification reaction component 3 is added to the separatory funnel and allowed to stand for 12 hours;

[0079] 7) The upper layer of the separation is the aqueous phase, and p-xylene is used to extract the methyl anthranilate in the aqueous phase. 1 g of the extract is prepared as a test sample and 2 g of internal standard propionic acid is added. The methyl anthranilate content in the aqueous phase is detected. The lower layer is the oil phase, the main component of which is methyl anthranilate. 1 g of the oil phase is prepared as a test sample and 2 g of internal standard propionic acid is added. The mass purity of methyl anthranilate is detected, and the total content of methyl anthranilate in the aqueous phase and the oil phase is obtained. The yield of methyl anthranilate is calculated. The yield of methyl anthranilate is 71%.

[0080] Example 2

[0081] 1) The sodium hypochlorite solution, methanol solution, and amidation solution were cooled to -10°C in advance, the first jet loop reactor 11 was set to a cooling temperature of -20°C, the kettle stirred reactor 21 was set to a temperature of 30°C, and the second jet loop reactor 31 was set to a temperature of 80°C;

[0082] 2) First, add 250 ml of methanol solution and 200 ml of amidation liquid into the first jet loop reactor 11 and circulate and mix for 5 minutes;

[0083] 3) After the circulating flow rate, temperature, and pressure stabilize, the sodium hypochlorite feed pump 13 is started to continuously deliver 250 ml of sodium hypochlorite solution to the ejector fluid inlet of the ejector 111 within 30 minutes. The sodium hypochlorite solution enters the suction chamber from the ejector fluid inlet, passes through the suction chamber, mixing chamber, and diffusion chamber in sequence to complete primary mixing. The material is continuously circulated by the circulating pump 113 and passes through the ejector 111 multiple times to complete mixing.

[0084] 4) Open the outlet valve to introduce the first reaction liquid from the Hofmann degradation reaction component 1 into the heating reaction component 2, add 4 g of sodium sulfite to the stirred tank reactor 21, and stir the reaction at 30° C. for 10 minutes;

[0085] 5) Open the outlet valve to introduce the second reaction liquid from the heating reaction component 2 into the esterification reaction component 3 to carry out the esterification reaction. The materials are circulated and mixed in the esterification reactor for 30 minutes;

[0086] 6) After the reaction is completed, the product obtained in the esterification reaction component 3 is added to the separatory funnel and allowed to stand for 12 hours;

[0087] 7) The upper layer of the separation is the aqueous phase, and p-xylene is used to extract the methyl anthranilate in the aqueous phase. 1 g of the extract is prepared as a test sample and 2 g of internal standard propionic acid is added to detect the methyl anthranilate content in the aqueous phase. The lower layer is the oil phase, the main component of which is methyl anthranilate. 1 g of the oil phase is prepared as a test sample and 2 g of internal standard propionic acid is added to detect the mass purity of methyl anthranilate. The total content of methyl anthranilate in the aqueous phase and the oil phase is obtained, and the yield of methyl anthranilate is calculated. The yield of methyl anthranilate is 61%.

[0088] Example 3

[0089] 1) The sodium hypochlorite solution, methanol solution, and amidation solution were cooled to -10°C in advance, the cooling temperature of the first jet loop reactor 11 was set to 10°C, the temperature of the stirred tank reactor 21 was set to 30°C, and the temperature of the second jet loop reactor 31 was set to 40°C;

[0090] 2) First, 300 ml of methanol solution and 200 ml of amidation liquid were added to the first jet loop reactor 11 and circulated and mixed for 5 minutes;

[0091] 3) After the circulating flow rate, temperature, and pressure stabilize, the sodium hypochlorite feed pump 13 is started to continuously deliver 350 ml of sodium hypochlorite solution to the ejector fluid inlet of the ejector 111 within 40 minutes. The sodium hypochlorite solution enters the suction chamber from the ejector fluid inlet, passes through the suction chamber, the mixing chamber, and the diffusion chamber in sequence to complete primary mixing. The material is continuously circulated by the circulating pump 113 and passes through the ejector 111 multiple times to complete mixing.

[0092] 4) Open the outlet valve to introduce the first reaction liquid from the Hofmann degradation reaction component 1 into the heating reaction component 2, add 4 g of sodium sulfite to the stirred tank reactor 21, and stir the reaction at 30° C. for 10 minutes;

[0093] 5) Open the outlet valve to introduce the second reaction liquid from the heating reaction component 2 into the esterification reaction component 3 to carry out the esterification reaction. The materials are circulated and mixed in the esterification reactor for 30 minutes;

[0094] 6) After the reaction is completed, the product obtained in the esterification reaction component 3 is added to the separatory funnel and allowed to stand for 12 hours;

[0095] 7) The upper layer of the separation is the aqueous phase, and p-xylene is used to extract the methyl anthranilate in the aqueous phase. 1 g of the extract is prepared as a test sample and 2 g of internal standard propionic acid is added. The methyl anthranilate content in the aqueous phase is detected. The lower layer is the oil phase, the main component of which is methyl anthranilate. 1 g of the oil phase is prepared as a test sample and 2 g of internal standard propionic acid is added. The mass purity of methyl anthranilate is detected, and the total content of methyl anthranilate in the aqueous phase and the oil phase is obtained. The yield of methyl anthranilate is calculated. The yield of methyl anthranilate is 59%.

[0096] Example 4

[0097] 1) The sodium hypochlorite solution, methanol solution, and amidation solution were cooled to -10°C in advance, the first jet loop reactor 11 was set to a cooling temperature of -20°C, the kettle stirred reactor 21 was set to a temperature of 30°C, and the second jet loop reactor 31 was set to a temperature of 70°C;

[0098] 2) First, 150 ml of methanol solution and 200 ml of amidation liquid were added to the first jet loop reactor 11 and circulated and mixed for 5 minutes;

[0099] 3) After the circulating flow rate, temperature, and pressure stabilize, the sodium hypochlorite feed pump 13 is started to continuously deliver 350 ml of sodium hypochlorite solution to the ejector fluid inlet of the ejector 111 within 50 minutes. The sodium hypochlorite solution enters the suction chamber from the ejector fluid inlet, passes through the suction chamber, mixing chamber, and diffusion chamber in sequence to complete primary mixing. The material is continuously circulated by the circulating pump 113 and passes through the ejector 111 multiple times to complete mixing.

[0100] 4) Open the outlet valve to introduce the first reaction liquid from the Hofmann degradation reaction component 1 into the heating reaction component 2, add 4 g of sodium sulfite to the stirred tank reactor 21, and stir the reaction at 30° C. for 10 minutes;

[0101] 5) Open the outlet valve to introduce the second reaction liquid from the heating reaction component 2 into the esterification reaction component 3 to carry out the esterification reaction. The materials are circulated and mixed in the esterification reactor for 50 minutes;

[0102] 6) After the reaction is completed, the product obtained in the esterification reaction component 3 is added to the separatory funnel and allowed to stand for 12 hours;

[0103] 7) The upper layer of the separation is the aqueous phase, and p-xylene is used to extract the methyl anthranilate in the aqueous phase. 1 g of the extract is prepared as a test sample and 2 g of internal standard propionic acid is added. The methyl anthranilate content in the aqueous phase is detected. The lower layer is the oil phase, the main component of which is methyl anthranilate. 1 g of the oil phase is prepared as a test sample and 2 g of internal standard propionic acid is added. The mass purity of methyl anthranilate is detected, and the total content of methyl anthranilate in the aqueous phase and the oil phase is obtained. The yield of methyl anthranilate is calculated. The yield of methyl anthranilate is 77%.

[0104] Example 5

[0105] 1) The sodium hypochlorite solution, methanol solution, and amidation solution were cooled to -10°C in advance, the cooling temperature of the first jet loop reactor 11 was set to 0°C, the temperature of the stirred tank reactor 21 was set to 30°C, and the temperature of the second jet loop reactor 31 was set to 80°C;

[0106] 2) First, 300 ml of methanol solution and 200 ml of amidation liquid were added to the first jet loop reactor 11 and circulated and mixed for 5 minutes;

[0107] 3) After the circulating flow rate, temperature, and pressure stabilize, the sodium hypochlorite feed pump 13 is started to continuously deliver 300 ml of sodium hypochlorite solution to the ejector fluid inlet of the ejector 111 within 50 minutes. The sodium hypochlorite solution enters the suction chamber from the ejector fluid inlet, passes through the suction chamber, mixing chamber, and diffusion chamber in sequence to complete primary mixing. The material is continuously circulated by the circulating pump 113 and passes through the ejector 111 multiple times to complete mixing.

[0108] 4) Open the outlet valve to introduce the first reaction liquid from the Hofmann degradation reaction component 1 into the heating reaction component 2, add 4 g of sodium sulfite to the stirred tank reactor 21, and stir the reaction at 30° C. for 10 minutes;

[0109] 5) Open the outlet valve to introduce the second reaction liquid from the heating reaction component 2 into the esterification reaction component 3 to carry out the esterification reaction. The materials are circulated and mixed in the esterification reactor for 10 minutes;

[0110] 6) After the reaction is completed, the product obtained in the esterification reaction component 3 is added to the separatory funnel and allowed to stand for 12 hours;

[0111] 7) The upper layer of the separation is the aqueous phase, and p-xylene is used to extract the methyl anthranilate in the aqueous phase. 1g of the extract is prepared as a test sample and 2g of internal standard propionic acid is added. The methyl anthranilate content in the aqueous phase is detected. The lower layer is the oil phase, the main component of which is methyl anthranilate. 1g of the oil phase is prepared as a test sample and 2g of internal standard propionic acid is added. The mass purity of methyl anthranilate is detected, and the total content of methyl anthranilate in the aqueous phase and the oil phase is obtained. The yield of methyl anthranilate is calculated. The yield of methyl anthranilate is 72%.

[0112] Example 6

[0113] 1) The sodium hypochlorite solution, methanol solution, and amidation solution were cooled to -10°C in advance, the cooling temperature of the first jet loop reactor 11 was set to -20°C, the temperature of the stirred tank reactor 21 was set to 30°C, and the temperature of the second jet loop reactor 31 was set to 50°C;

[0114] 2) First, add 200 ml of methanol solution and 200 ml of amidation liquid into the first jet loop reactor 11 and circulate and mix for 5 minutes;

[0115] 3) After the circulating flow rate, temperature, and pressure stabilize, the sodium hypochlorite feed pump 13 is started to continuously deliver 300 ml of sodium hypochlorite solution to the ejector fluid inlet of the ejector 111 within 40 minutes. The sodium hypochlorite solution enters the suction chamber from the ejector fluid inlet, passes through the suction chamber, mixing chamber, and diffusion chamber in sequence to complete primary mixing. The material is continuously circulated by the circulating pump 113 and passes through the ejector 111 multiple times to complete mixing.

[0116] 4) Open the outlet valve to introduce the first reaction liquid from the Hofmann degradation reaction component 1 into the heating reaction component 2, add 4 g of sodium sulfite to the stirred tank reactor 21, and stir the reaction at 30° C. for 10 minutes;

[0117] 5) Open the outlet valve to introduce the second reaction liquid from the heating reaction component 2 into the esterification reaction component 3 to carry out the esterification reaction. The materials are circulated and mixed in the esterification reactor for 40 minutes;

[0118] 6) After the reaction is completed, the product obtained in the esterification reaction component 3 is added to the separatory funnel and allowed to stand for 12 hours;

[0119] 7) The upper layer of the separation is the aqueous phase, and p-xylene is used to extract the methyl anthranilate in the aqueous phase. 1 g of the extract is prepared as a test sample and 2 g of internal standard propionic acid is added. The methyl anthranilate content in the aqueous phase is detected. The lower layer is the oil phase, the main component of which is methyl anthranilate. 1 g of the oil phase is prepared as a test sample and 2 g of internal standard propionic acid is added. The mass purity of methyl anthranilate is detected, and the total content of methyl anthranilate in the aqueous phase and the oil phase is obtained. The yield of methyl anthranilate is calculated. The yield of methyl anthranilate is 69%.

[0120] Example 7

[0121] 1) The sodium hypochlorite solution, methanol solution, and amidation solution were cooled to -10°C in advance. The cooling temperature of the first jet loop reactor 11 was set to -10°C, the temperature of the stirred tank reactor 21 was set to 30°C, and the temperature of the second jet loop reactor 31 was set to 40°C;

[0122] 2) First, add 250 ml of methanol solution and 200 ml of amidation liquid into the first jet loop reactor 11 and circulate and mix for 5 minutes;

[0123] 3) After the circulating flow rate, temperature, and pressure stabilize, the sodium hypochlorite feed pump 13 is started to continuously deliver 300 ml of sodium hypochlorite solution to the ejector fluid inlet of the ejector 111 within 20 minutes. The sodium hypochlorite solution enters the suction chamber from the ejector fluid inlet, passes through the suction chamber, mixing chamber, and diffusion chamber in sequence to complete primary mixing. The material is continuously circulated by the circulating pump 113 and passes through the ejector 111 multiple times to complete mixing;

[0124] 4) Open the outlet valve to introduce the first reaction liquid from the Hofmann degradation reaction component 1 into the heating reaction component 2, add 4 g of sodium sulfite to the stirred tank reactor 21, and stir the reaction at 30° C. for 10 minutes;

[0125] 5) Open the outlet valve to introduce the second reaction liquid from the heating reaction component 2 into the esterification reaction component 3 to carry out the esterification reaction. The materials are circulated and mixed in the esterification reactor for 50 minutes;

[0126] 6) After the reaction is completed, the product obtained in the esterification reaction component 3 is added to the separatory funnel and allowed to stand for 12 hours;

[0127] 7) The upper layer of the separation is the aqueous phase, and p-xylene is used to extract the methyl anthranilate in the aqueous phase. 1 g of the extract is prepared as a test sample and 2 g of internal standard propionic acid is added to detect the methyl anthranilate content in the aqueous phase. The lower layer is the oil phase, the main component of which is methyl anthranilate. 1 g of the oil phase is prepared as a test sample and 2 g of internal standard propionic acid is added to detect the mass purity of methyl anthranilate. The total content of methyl anthranilate in the aqueous phase and the oil phase is obtained, and the yield of methyl anthranilate is calculated. The yield of methyl anthranilate is 58%.

[0128] Example 8

[0129] 1) The sodium hypochlorite solution, methanol solution, and amidation solution were cooled to -10°C in advance, the cooling temperature of the first jet loop reactor 11 was set to 0°C, the temperature of the stirred tank reactor 21 was set to 30°C, and the temperature of the second jet loop reactor 31 was set to 60°C;

[0130] 2) First, 100 ml of methanol solution and 200 ml of amidation liquid were added to the first jet loop reactor 11 and circulated and mixed for 5 minutes;

[0131] 3) After the circulating flow rate, temperature, and pressure stabilize, the sodium hypochlorite feed pump 13 is started to continuously deliver 250 ml of sodium hypochlorite solution to the ejector fluid inlet of the ejector 111 within 40 minutes. The sodium hypochlorite solution enters the suction chamber from the ejector fluid inlet, passes through the suction chamber, mixing chamber, and diffusion chamber in sequence to complete primary mixing. The material is continuously circulated by the circulating pump 113 and passes through the ejector 111 multiple times to complete mixing.

[0132] 4) Open the outlet valve to introduce the first reaction liquid from the Hofmann degradation reaction component 1 into the heating reaction component 2, add 4 g of sodium sulfite to the stirred tank reactor 21, and stir the reaction at 30° C. for 10 minutes;

[0133] 5) Open the outlet valve to introduce the second reaction liquid from the heating reaction component 2 into the esterification reaction component 3 to carry out the esterification reaction. The materials are circulated and mixed in the esterification reactor for 50 minutes;

[0134] 6) After the reaction is completed, the product obtained in the esterification reaction component 3 is added to the separatory funnel and allowed to stand for 12 hours;

[0135] 7) The upper layer of the separation is the aqueous phase, and p-xylene is used to extract the methyl anthranilate in the aqueous phase. 1 g of the extract is prepared as a test sample and 2 g of internal standard propionic acid is added. The methyl anthranilate content in the aqueous phase is detected. The lower layer is the oil phase, the main component of which is methyl anthranilate. 1 g of the oil phase is prepared as a test sample and 2 g of internal standard propionic acid is added. The mass purity of methyl anthranilate is detected, and the total content of methyl anthranilate in the aqueous phase and the oil phase is obtained. The yield of methyl anthranilate is calculated. The yield of methyl anthranilate is 49%.

[0136] The embodiment of the present application adopts a jet loop reactor to provide a more environmentally friendly process route for the continuous preparation of methyl anthranilate, which can enhance the mass transfer and heat transfer during the reaction of the sodium hypochlorite solution with the methanol solution and the amidation liquid mixture in the Hofmann reaction stage, shorten the production cycle, reduce labor costs, improve the production environment, and reduce energy consumption and raw material consumption. In addition, the jet loop reactor has a simple structure, high operational flexibility, good sealing, low equipment manufacturing cost and subsequent repair and maintenance, which is conducive to scale-up and continuous industrial production.

[0137] The above is a detailed introduction to the preparation device and preparation method of methyl anthranilate provided by the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. At the same time, for those skilled in the art, according to the ideas of the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present application.

Claims

1. A method for preparing methyl anthranilate, characterized in that: The preparation is carried out in the preparation device of methyl anthranilate, The preparation device of methyl anthranilate comprises: A Hofmann degradation reaction assembly (1), comprising a first jet loop reactor (11), a circulating cooling pump (12) and a sodium hypochlorite feed pump (13), wherein the sodium hypochlorite feed pump (13) is connected to the first jet loop reactor (11); A heating reaction component (2), wherein the heating reaction component (2) comprises a kettle-type stirred reactor (21); An esterification reaction component (3), the esterification reaction component (3) comprising a second jet loop reactor (31) and a water feed pump (32), the water feed pump (32) and the second jet loop reactor (31) being connected, and the esterification reaction component (3) being connected to the Hofmann degradation reaction component (1) via the heating reaction component (2); The first jet loop reactor (11) and the second jet loop reactor (31) respectively comprise an ejector (111), a reactor (112), a circulation pump (113), a heat exchanger (114) and a detector (115), wherein the ejector (111), the reactor (112), the circulation pump (113), the heat exchanger (114) and the detector (115) form a circulation loop; wherein the circulation cooling pump (12) is connected to the corresponding heat exchanger (114), and the heat exchanger (114) is connected to the corresponding circulation pump (113); The preparation method comprises: Providing pre-cooled methanol solution, sodium hypochlorite solution and sodium o-formamidobenzoate aqueous solution; In the Hofmann degradation reaction component (1), the methanol solution and the sodium o-formamidobenzoate aqueous solution are added to the first jet loop reactor (11), the circulation pump (113) and the circulation cooling pump (12) in the Hofmann degradation reaction component (1) are started, and the circulation mixing of the materials is achieved through the circulation pump (113); The sodium hypochlorite feed pump (13) is started, and the sodium hypochlorite solution is added to the first jet loop reactor (11). After circulating and mixing, a first reaction occurs. The first reaction time is 10 minutes, and the first reaction liquid after the reaction is transported to the heating reaction component (2); Sodium sulfite is added to the stirred tank reactor (21) to undergo a second reaction with an excess of the sodium hypochlorite solution, wherein the second reaction lasts for 10 to 30 minutes, and the second reaction liquid after the reaction is transported to the esterification reaction component (3); The circulation pump (113) and the heat exchanger (114) in the esterification reaction component (3) are started, the water feed pump (32) is started, water is added to the second jet loop reactor (31), circulated and mixed, and a third reaction is carried out to obtain a third reaction liquid. The time of the third reaction is 10 minutes to 50 minutes.

2. The preparation method of methyl anthranilate according to claim 1, wherein The detector (115) includes one or more of a flow detector, a pressure detector or a temperature detector.

3. The preparation method of methyl anthranilate according to claim 1, wherein The stirring blade of the kettle-type stirred reactor (21) is a paddle-type stirring blade or a turbine-type stirring blade.

4. The preparation method of methyl anthranilate according to claim 1, wherein The heat exchanger (114) comprises a shell and tube heat exchanger.

5. The preparation method of methyl anthranilate according to claim 1, wherein The ejector (111) comprises a nozzle, a suction chamber, a mixing chamber and a diffusion chamber.

6. The method for preparing methyl anthranilate according to claim 1, wherein The pre-cooling temperature is -20°C to 0°C.

7. The method for preparing methyl anthranilate according to claim 1, wherein The volume ratio of the sodium o-formamidobenzoate aqueous solution to the methanol solution is 1:(0.5-1.5), and the volume ratio of the sodium hypochlorite solution to the sodium o-formamidobenzoate aqueous solution is in the range of (0.75-1.80):

1.

8. The method for preparing methyl anthranilate according to claim 1, wherein The concentration of effective chlorine element in the sodium hypochlorite solution is 7.5% to 16%, and the concentration of methanol in the methanol solution is 75% to 100%.

9. The method for preparing methyl anthranilate according to claim 1, wherein The temperature of the first reaction is -20°C to 20°C, the temperature of the second reaction is 20°C to 30°C, and the temperature of the third reaction is 40°C to 80°C.

10. The method for preparing methyl anthranilate according to claim 1, wherein The preparation method further comprises: allowing the third reaction liquid to stand, separating and extracting to obtain the methyl anthranilate.

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