CN112250590B - Method for continuously preparing methyl anthranilate - Google Patents
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- CN112250590B CN112250590B CN202011065155.5A CN202011065155A CN112250590B CN 112250590 B CN112250590 B CN 112250590B CN 202011065155 A CN202011065155 A CN 202011065155A CN 112250590 B CN112250590 B CN 112250590B
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- C07C227/14—Preparation of compounds containing amino and carboxyl groups bound to the same carbon skeleton from compounds containing already amino and carboxyl groups or derivatives thereof
- C07C227/18—Preparation of compounds containing amino and carboxyl groups bound to the same carbon skeleton from compounds containing already amino and carboxyl groups or derivatives thereof by reactions involving amino or carboxyl groups, e.g. hydrolysis of esters or amides, by formation of halides, salts or esters
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Abstract
The invention relates to the field of biological medicines, and in particular relates to a method for continuously preparing methyl anthranilate. The method comprises the steps of injecting a sodium o-formamide benzoate methanol solution and a sodium hypochlorite solution which are prepared by mixing phthalimide, liquid caustic soda, methanol and water into a reaction cavity of a horizontally arranged tubular reactor from one end of the tubular reactor, injecting the sodium o-formamide benzoate methanol solution and the sodium hypochlorite solution to push materials in the reaction cavity to move forward towards the other end of the tubular reactor while carrying out mixed reaction, mixing the materials at the front section of the tubular reactor under the stirring of an axial stirring column of the vertical tubular reactor, carrying out Hofmann degradation reaction at the middle section and the rear section of the tubular reactor, finally moving forward to the other end of the tubular reactor to be discharged, and hydrolyzing to obtain the methyl o-aminobenzoate. The method can eliminate local back mixing in the preparation process, has good mass transfer effect, short reaction retention time, high yield and large reaction flux, can avoid blockage of the reactor, and can be put into continuous large-scale production.
Description
Technical Field
The invention relates to the field of biological medicines, and in particular relates to a method for continuously preparing methyl anthranilate.
Background
Methyl anthranilate is mainly used as an intermediate for synthesizing dyes, medicines, pesticides and perfumes. In the aspect of dyes, the dye is used for preparing azo dyes, anthraquinone dyes and indigoid dyes. In the aspect of medicine, the compound is used for preparing an antiarrhythmic drug of everoline, vitamin L, a nonsteroidal anti-inflammatory analgesic drug of mefenamic acid, Yantongjing, a non-barbiturate hypnotic drug of hypnone and a strong tranquilizer of tylden. At present, two methods are mainly used for synthesizing methyl anthranilate, one is to perform amidation reaction on phthalic anhydride and ammonia to generate sodium anthranilate, the sodium anthranilate is generated through sodium hypochlorite degradation reaction, and the sodium anthranilate is finally neutralized to obtain the methyl anthranilate, and the other is to perform reduction esterification on the o-nitrobenzoic acid or perform salification, diazotization, reduction and cyclization on the o-nitrobenzoic acid serving as a raw material to obtain the methyl anthranilate. The former has complex production steps, high process requirements and high cost, and the latter not only uses expensive raw material o-nitrobenzoic acid, but also needs an iron powder reduction method or catalytic hydrogenation in the presence of Raney nickel to prepare methyl anthranilate, and then directly esterifies, thereby not only generating a large amount of waste water, but also forming inner salt of anthranilic acid, using a large amount of catalysts, and having low esterification yield.
At the present stage, the industry generally adopts an intermittent production mode of a reaction kettle, potential safety hazards exist in the process, and the purity and the yield of the methyl anthranilate obtained by the reaction are not high; meanwhile, the production process is accompanied by the generation of wastewater to pollute the environment, which is not favorable for the development concept of 'safety, green, energy saving and environmental protection' advocated at present.
Chinese patent "a preparation method of methyl anthranilate by using a microchannel reactor" (publication No. CN106905172A, published 2017.06.30) discloses a preparation method of methyl anthranilate by using a microchannel reactor, and specifically discloses that phthalimide source liquid and sodium hypochlorite solution are pumped into a mixing module MRX of a microchannel reactor, mixed and reacted, and then enter a reaction module MRH of the microchannel reactor.
Chinese patent "a method for continuously preparing methyl anthranilate" (publication No. CN 110229077A, published Japanese 2019.09.13) discloses a method for continuously preparing methyl anthranilate, which comprises the steps of respectively pouring a methanol solution of anthranilic acid and a concentrated sulfuric acid solution into a mixed reaction chamber of a microchannel reactor, and carrying out a preheating reaction in the mixed reaction chamber to form a mixed solution containing methyl anthranilate; and neutralizing the sodium hydroxide solution and the mixed solution, and cooling to separate out methyl anthranilate.
The patent of the method for preparing methyl anthranilate utilizes the microchannel reactor to prepare methyl anthranilate, has short reaction time, and the prepared methyl anthranilate product has high purity and high yield, thereby overcoming the defects of the traditional preparation method at present, realizing continuous preparation and improving the production efficiency. However, temperature change operation is required in the process of preparing methyl anthranilate, the temperature required by mixing reaction is high, the neutralization reaction temperature is low, methyl anthranilate is crystallized and separated out under the low-temperature condition, the normal operation of a fine pipeline of a microchannel reactor is not facilitated, the blockage is easy to occur, in addition, the flux of the microchannel reactor is small, the large-scale production and application are limited, the non-uniform mixing, the relatively poor heat exchange effect and the back-mixing phenomenon are easy to occur in the reaction process, the reaction rates of different positions of the reactor are inconsistent, and the mass transfer speed and the product yield are influenced.
Disclosure of Invention
The invention aims to overcome at least one defect (deficiency) of the prior art and provides a method for continuously preparing methyl anthranilate, which is used for eliminating local back mixing in the process of preparing methyl anthranilate, and has the advantages of good mass and heat transfer mixing effect, good flexibility in selecting a mixing section and a reaction section, high safety performance, short reaction retention time, good selectivity, high yield and larger reaction flux, can effectively avoid blockage of a reactor, and can realize continuous large-scale production.
The technical scheme adopted by the invention is that a methyl anthranilate continuous preparation method comprises the steps of injecting a methyl anthranilate methanol solution and a sodium hypochlorite solution which are prepared by mixing phthalimide, caustic soda liquid, methanol and water into a reaction cavity of a horizontally arranged tubular reactor from one end of the tubular reactor, pushing the methyl anthranilate methanol solution and the sodium hypochlorite solution in the reaction cavity to advance to the other end of the tubular reactor while carrying out mixed reaction, mixing at the front section of the tubular reactor under the stirring of an axial stirring column of a vertical tubular reactor, carrying out Hofmann degradation reaction at the middle section and the rear section of the tubular reactor, finally advancing to the other end of the tubular reactor, discharging, and hydrolyzing to obtain the methyl anthranilate.
In the traditional reactor, the baffle is generally arranged to isolate materials before and after reaction so as to improve the yield, but the baffle is not beneficial to mass transfer, so in the technical scheme, the reaction materials flowing in the reaction cavity are stirred by the stirring column to replace the baffle to isolate the materials before and after reaction, thereby not only realizing isolation, but also providing a larger specific surface area to facilitate mass transfer, so that the contradiction problem between isolation and mass transfer is solved, and the product yield is further optimized; the stirring column vertical to the rotating shaft stirs the materials in the tangential direction, so that the materials are mixed more uniformly, forward or backward driving force cannot be generated on the materials, and the back mixing phenomenon of the materials is effectively avoided; secondly, the materials are stirred by the stirring column, so that the phenomenon that the reaction cavity is blocked by the crystallization of the methyl anthranilate is effectively avoided under the low-temperature reaction condition.
Preferably, the front section of the tubular reactor is a mixing section, the middle section and the rear section are reaction sections, and the mixing section is communicated with the reaction sections in series.
In the technical scheme, the adopted reactor has larger flux, the reaction materials are firstly mixed in the mixing section, cooled to the temperature required by the reaction, and reacted in the reaction section.
Further, the molar ratio of the sodium o-formamide benzoate to the methanol in the sodium o-formamide benzoate methanol solution is that the molar ratio of the sodium o-formamide benzoate to the methanol is: methanol is 1:1.05 to 1.25.
Preferably, the molar ratio of the sodium o-formamide benzoate to the methanol in the sodium o-formamide benzoate methanol solution is the following: methanol is 1: 1.15.
Further, the preparation of the methanol solution of sodium orthoformamide benzoate comprises the following steps: adding water and liquid caustic soda into phthalimide, heating to react until the phthalimide is completely dissolved, and obtaining amidation liquid containing sodium benzoate of the o-formamide; and adding methanol into the amidation liquid to obtain the methanol solution of the o-formamide sodium benzoate.
Further, the volume ratio of the o-formamide sodium benzoate methanol solution to the sodium hypochlorite solution is that of the o-formamide sodium benzoate methanol solution: the sodium hypochlorite solution is 1: 1.0-2.2.
Preferably, the volume ratio of the o-formamide sodium benzoate methanol solution to the sodium hypochlorite solution is the o-formamide sodium benzoate methanol solution: sodium hypochlorite solution 1: 1.05.
Furthermore, the concentration of the phthalimide is 2.0-3.5 mol/L, or the liquid caustic soda is 2.0-4.0 mol/L sodium hydroxide, or the concentration of the methanol is 8.0-11.0 mol/L, or the concentration of the sodium hypochlorite solution is 10-20%.
Preferably, the concentration of the phthalimide is 2.5mol/L, or the concentration of the sodium hydroxide is 2.5mol/L, or the concentration of the methanol is 10.0mol/L, or the concentration of the sodium hypochlorite solution is 15%.
Further, the reaction temperature of the o-formamide sodium benzoate methanol solution and the sodium hypochlorite solution in the tubular reactor is controlled to be-10-5 ℃ through a cooling medium surrounding the reaction cavity, and the reaction time is 5-30 s.
Preferably, the reaction temperature of the o-formamide sodium benzoate methanol solution and the sodium hypochlorite solution in the tubular reactor is controlled to be-5 ℃ by a cooling medium surrounding the reaction cavity, and the reaction time is 8 s.
In this technical scheme, through cooling medium parcel reaction chamber control reaction temperature, can be better cool off, make the temperature gradient of each part in the reaction chamber littleer, be favorable to controlling reaction rate, prevent to cool off inhomogeneous, local reaction cooling is not abundant.
Further, hydrolyzing the material discharged from the other end of the tubular reactor at 40-70 ℃.
Preferably, the material discharged from the other end of the tubular reactor is hydrolyzed at 45-65 ℃.
Preferably, the material of the dynamic tangential flow tubular reactor adopts SiC, Hastelloy or silicon rubber.
More preferably, the inner wall surface of the reaction cavity of the dynamic tangential flow tubular reactor is made of SiC, Hastelloy or silicone rubber.
In the technical scheme, SiC, hastelloy or silicon rubber is used as a material of the dynamic tangential flow tubular reactor, so that the reactor is more resistant to low temperature and corrosion, the service life of the reactor is prolonged, the heat conduction efficiency of the reactor is improved, and reaction materials can be better cooled.
Compared with the prior art, the invention has the beneficial effects that:
(1) the stirring column vertical to the rotating shaft stirs the materials in the tangential direction, so that the materials are mixed more uniformly without pushing the materials, the back mixing phenomenon of the materials is effectively avoided, and the product selectivity and yield are improved;
(2) the stirring column vertical to the rotating shaft stirs the materials in the tangential direction, so that the phenomenon that the methyl anthranilate crystal is separated out to block a reaction cavity at low temperature is avoided;
(3) the cooling fluid wraps the reaction cavity to control the reaction temperature, so that the reaction speed is controlled, and insufficient cooling of local reaction is avoided;
(4) the residence time of the reaction materials is short, and the production efficiency is improved;
(5) the reaction flux is large, and the method can be put into large-scale production.
Drawings
FIG. 1 is an axial sectional view of a tubular reactor used for the continuous production of methyl anthranilate according to the present invention.
FIG. 2 is an enlarged partial view of an axial cross-sectional view of a tubular reactor employed in the continuous production of methyl anthranilate of the present invention.
In the drawings are labeled: 1-a rotary power assembly; 2-a heat exchange fluid inlet; 3-a raw material feed inlet; 4-heat exchange jacket; 5-a heat exchange fluid outlet; 6-discharge hole of reaction product; 12-a stirring column; 13-a hollow rotating shaft; 14-a reaction chamber; 15-reactor shell.
Detailed Description
The drawings are only for purposes of illustration and are not to be construed as limiting the invention. For a better understanding of the following embodiments, certain features of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.
As shown in fig. 1 and fig. 2, the tubular reactor adopted in the method for continuously preparing methyl anthranilate of the present invention is disposed horizontally, the reactor material is SiC material, hastelloy or silicone rubber, and comprises a reactor shell 15, a hollow rotating shaft 13 disposed in the reactor shell, a rotating power assembly 1 for connecting the hollow rotating shaft 13 and the reactor shell 15, and a material inlet and outlet assembly disposed on the outer wall surface of the reactor shell, wherein a heat exchange component is further disposed outside the reactor shell 15; a plurality of stirring columns 12 are vertically arranged on the outer wall surface of the hollow rotating shaft 13; a reaction chamber 14 is formed between the inner wall surface of the reactor shell 15 and the outer wall surface of the hollow rotating shaft 13.
The inlet and outlet assembly comprises a plurality of raw material inlet openings 3 and reaction product outlet openings 6; the hollow rotating shaft 13 is used for internal heat exchange cooling, the cooling part comprises a cooling jacket 4, a cooling medium inlet 2 and a cooling medium outlet 5, the cooling medium inlet 2 is arranged at the left end of the lower side of the cooling jacket 4, and the cooling medium outlet 5 is arranged at the right end of the upper side of the cooling jacket 4.
During the use, cooling medium from the injection of cooling medium entry 2, discharge from cooling medium export 5, make cooling medium parcel reaction chamber, carry out external cooling, the cooling medium flow direction is from first raw materials feed inlet 2 to reaction products discharge gate 6, such flow direction adapts to the exothermic law of continuous reaction, more be favorable to the cooling among the reaction process, thereby better control reaction temperature, the inside and outside two-sided cooling of reaction space, the heat transfer, the temperature gradient that makes each part in the reaction chamber is littleer, cooling efficiency is improved, be favorable to controlling reaction speed, it is inhomogeneous to prevent local reaction cooling.
The reaction chamber between the first raw material feed inlet 3 and the second raw material feed inlet 3 is a mixing section, a reaction section is arranged between the second raw material feed inlet and the reaction product discharge port 6, the reaction product enters from the first raw material feed inlet 3, the mixture is mixed in the mixing section, the temperature is reduced to the temperature required by the reaction, and the reaction is carried out in the reaction section.
The rotary power component 1 fixes the hollow rotating shaft 13 and provides rotary power for the hollow rotating shaft 13, the hollow rotating shaft 13 is used for driving the stirring column 12, the stirring column 12 is vertically arranged on the outer wall surface of the hollow rotating shaft 13, materials can be stirred in the tangential direction along with the rotation of the hollow rotating shaft 13, so that the materials are mixed more uniformly, the stirring column 12 is vertical to the outer wall surface of the hollow rotating shaft 13, the materials are stirred in the tangential direction, forward or backward driving force cannot be generated on the materials, the materials are mainly driven by the driving force generated by continuous injection of new materials, so that the back mixing phenomenon of the materials is eliminated, the reaction materials are stirred through the stirring column 12, the traditional isolation baffle which is not beneficial to mass transfer can be replaced, the isolation of the reaction materials is realized, the mass transfer is facilitated, and the yield of products is further improved; meanwhile, the materials are stirred by the stirring column, so that the phenomenon that the reaction cavity is blocked by the crystallization of the methyl anthranilate is effectively avoided under the low-temperature reaction condition.
The invention provides a method for continuously preparing methyl anthranilate, which comprises the following steps:
s1, respectively adding water, phthalimide and liquid caustic soda into a reaction kettle, heating to 50-55 ℃, maintaining the pH at about 13 after 30 minutes, maintaining the pH at not less than 12.5 after 40 minutes, and heating until the phthalimide is completely dissolved in the reaction kettle to obtain the amidation liquid containing the sodium phthalamide.
S2, transferring the amidation liquid containing the sodium o-formamide benzoate obtained in the step S1 into a degradation esterification kettle, cooling to-5 ℃, adding methanol into the degradation esterification kettle according to the molar ratio and the material concentration, and controlling the temperature in the degradation esterification kettle to be below-7 ℃ and the pH value to be not lower than 9 to obtain a methanol solution of the sodium o-formamide benzoate.
S3, introducing a cooling medium into a cooling jacket 4 of the reactor, controlling the reaction temperature at-10-5 ℃, injecting the o-formamide sodium benzoate methanol solution and the sodium hypochlorite solution prepared in the step S2 into a reaction cavity 14 of the tubular reactor from a first raw material inlet 3 by using a metering pump respectively, pushing the o-formamide sodium benzoate methanol solution and the sodium hypochlorite solution in the reaction cavity 14 to advance towards a reaction product outlet 6 of the tubular reactor while carrying out mixed reaction, under the stirring of an axial stirring column 12 of the vertical tubular reactor, the methanol solution of the sodium orthoformamide benzoate and the sodium hypochlorite solution are uniformly mixed and cooled in a mixing section of the tubular reactor, and then the mixture is moved to a reaction section of the tubular reactor to carry out Hofmann degradation reaction, and after staying in the reactor for 5-30 seconds, the material is conveyed to a reaction product discharge port 6 of the tubular reactor and discharged.
S4, collecting the material discharged in the step S3, putting the material into a hydrolysis kettle, heating to 40-70 ℃, and hydrolyzing to obtain the methyl anthranilate.
Example 1
In this example, methyl anthranilate was continuously prepared according to the above method, using phthalimide with a concentration of 2mol/L, sodium hydroxide with a concentration of 2mol/L, methanol with a concentration of 8mol/L, and sodium hypochlorite solution with a concentration of 10%, wherein the molar ratio of sodium anthranilate to methanol was sodium anthranilate: the volume ratio of the o-formamide sodium benzoate methanol solution to the sodium hypochlorite solution is 1:1.15, and the o-formamide sodium benzoate methanol solution: sodium hypochlorite solution 1: 1.0; in step S3, the reaction temperature is controlled at-10 ℃, and the reaction materials stay in the reactor for 5S; in step S4, the hydrolysis kettle temperature is controlled at 40 ℃.
The purity of the target product methyl anthranilate is 99.5 percent and the product yield is 96.2 percent after the obtained product is analyzed.
Example 2
In this example, methyl anthranilate was continuously prepared according to the above method, using phthalimide with a concentration of 2.5mol/L, sodium hydroxide with a concentration of 2.5mol/L, methanol with a concentration of 10mol/L, and sodium hypochlorite solution with a concentration of 15%, wherein the molar ratio of sodium anthranilate to methanol was sodium anthranilate: the volume ratio of the o-formamide sodium benzoate methanol solution to the sodium hypochlorite solution is 1:1.15, and the o-formamide sodium benzoate methanol solution: sodium hypochlorite solution 1: 1.05; in step S3, the reaction temperature is controlled at-5 ℃, and the reaction materials stay in the reactor for 8S; in step S4, the hydrolysis kettle temperature is controlled at 45 ℃.
The purity of the target product methyl anthranilate is 99.7 percent and the product yield is 95.4 percent after the obtained product is analyzed.
Example 3
In this example, methyl anthranilate was continuously prepared according to the above steps, using phthalimide with a concentration of 3mol/L, sodium hydroxide with a concentration of 3mol/L, methanol with a concentration of 11mol/L, and sodium hypochlorite solution with a concentration of 20%, wherein the molar ratio of sodium anthranilate to methanol was sodium anthranilate: the volume ratio of the o-formamide sodium benzoate methanol solution to the sodium hypochlorite solution is 1:1.15, and the o-formamide sodium benzoate methanol solution: sodium hypochlorite solution 1: 1.5; in step S3, the reaction temperature is controlled at 0 ℃, and the reaction materials stay in the reactor for 15S; in step S4, the hydrolysis kettle temperature is controlled at 55 ℃.
The purity of the target product methyl anthranilate is 99.8 percent and the product yield is 93.7 percent after the obtained product is analyzed.
Example 4
In this example, methyl anthranilate was continuously prepared according to the above method, using phthalimide with a concentration of 3.5mol/L, sodium hydroxide with a concentration of 4mol/L, methanol with a concentration of 9mol/L, and sodium hypochlorite solution with a concentration of 18%, wherein the molar ratio of sodium anthranilate to methanol was sodium anthranilate: the volume ratio of the o-formamide sodium benzoate methanol solution to the sodium hypochlorite solution is 1:1.15, and the o-formamide sodium benzoate methanol solution: sodium hypochlorite solution 1: 2.2; in step S3, the reaction temperature is controlled at 5 ℃, and the reaction materials stay in the reactor for 20S; in step S4, the hydrolysis kettle temperature is controlled at 65 ℃.
The purity of the target product methyl anthranilate is 99.6 percent and the product yield is 91.3 percent after the obtained product is analyzed.
Example 5
In this example, methyl anthranilate was continuously prepared according to the above method, using phthalimide with a concentration of 2.5mol/L, sodium hydroxide with a concentration of 3.5mol/L, methanol with a concentration of 10mol/L, and sodium hypochlorite solution with a concentration of 12%, wherein the molar ratio of sodium anthranilate to methanol was sodium anthranilate: the volume ratio of the o-formamide sodium benzoate methanol solution to the sodium hypochlorite solution is 1:1.15, and the o-formamide sodium benzoate methanol solution: sodium hypochlorite solution 1: 1.3; in step S3, the reaction temperature is controlled at-3 ℃, and the reaction materials stay in the reactor for 30S; in step S4, the hydrolysis kettle temperature is controlled at 70 ℃.
The purity of the target product methyl anthranilate is 99.9 percent and the product yield is 94.5 percent after the obtained product is analyzed.
Example 6
In this example, methyl anthranilate was continuously prepared according to the above method, using phthalimide with a concentration of 2.2mol/L, sodium hydroxide with a concentration of 3.5mol/L, methanol with a concentration of 10mol/L, and sodium hypochlorite solution with a concentration of 10%, wherein the molar ratio of sodium anthranilate to methanol was sodium anthranilate: the volume ratio of the o-formamide sodium benzoate methanol solution to the sodium hypochlorite solution is 1:1.15, and the o-formamide sodium benzoate methanol solution: sodium hypochlorite solution 1: 1.8; in step S3, the reaction temperature is controlled at-8 ℃, and the reaction materials stay in the reactor for 25S; in step S4, the hydrolysis kettle temperature is controlled at 50 ℃.
The purity of the target product methyl anthranilate is 99.6 percent and the product yield is 93.8 percent after the obtained product is analyzed.
Example 7
In this example, methyl anthranilate was continuously prepared according to the above method, using phthalimide with a concentration of 3.3mol/L, sodium hydroxide with a concentration of 2.5mol/L, methanol with a concentration of 8mol/L, and sodium hypochlorite solution with a concentration of 16%, wherein the molar ratio of sodium anthranilate to methanol was sodium anthranilate: the volume ratio of the o-formamide sodium benzoate methanol solution to the sodium hypochlorite solution is 1: 1.05: sodium hypochlorite solution 1: 2.0; in step S3, the reaction temperature is controlled at 3 ℃, and the reaction materials stay in the reactor for 13S; in step S4, the hydrolysis kettle temperature is controlled at 43 ℃.
The purity of the target product methyl anthranilate is 99.8 percent and the product yield is 91.9 percent after the obtained product is analyzed.
Example 8
In this example, methyl anthranilate was continuously prepared according to the above method, using phthalimide with a concentration of 2.7mol/L, sodium hydroxide with a concentration of 2.7mol/L, methanol with a concentration of 9mol/L, and sodium hypochlorite solution with a concentration of 15%, wherein the molar ratio of sodium anthranilate to methanol was sodium anthranilate: the volume ratio of the o-formamido sodium benzoate methanol solution to the sodium hypochlorite solution is 1: 1.25: sodium hypochlorite solution 1: 1.2; in step S3, the reaction temperature is controlled at-5 ℃, and the reaction materials stay in the reactor for 8S; in step S4, the hydrolysis kettle temperature is controlled at 60 ℃.
The purity of the target product methyl anthranilate is 99.7 percent and the product yield is 94.3 percent after the obtained product is analyzed.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
It should be understood that the above-mentioned embodiments of the present invention are only examples for clearly illustrating the technical solutions of the present invention, and are not intended to limit the specific embodiments of the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention claims should be included in the protection scope of the present invention claims.
Claims (10)
1. A method for continuously preparing methyl anthranilate is characterized in that a methyl anthranilate methanol solution and a sodium hypochlorite solution which are prepared by mixing phthalimide, caustic soda liquid, methanol and water are injected into a reaction cavity of a horizontally arranged tubular reactor from one end of the tubular reactor, the methyl anthranilate methanol solution and the sodium hypochlorite solution in the reaction cavity are pushed to advance towards the other end of the tubular reactor while being mixed and reacted by the injection of the methyl anthranilate methanol solution and the sodium hypochlorite solution, the methyl anthranilate methanol solution and the sodium hypochlorite solution are mixed at the front section of the tubular reactor under the stirring of an axial stirring column of the vertical tubular reactor, the methyl anthranilate methanol solution and the sodium hypochlorite solution are subjected to Hofmann degradation reaction at the middle section and the rear section of the tubular reactor, and finally the methyl anthranilate is discharged from the other end of the tubular reactor and hydrolyzed to obtain the methyl anthranilate;
the reaction time of the o-formamide sodium benzoate methanol solution and the sodium hypochlorite solution in the tubular reactor is 5-30 s; the stirring column only stirs the material in the tangential direction.
2. The method for continuously preparing the methyl anthranilate according to claim 1, characterized in that the molar ratio of the sodium anthranilate to the methanol in the sodium anthranilate methanol solution is the sodium anthranilate: methanol is 1:1.05 to 1.25.
3. The method for continuously preparing methyl anthranilate according to claim 1, characterized in that the phthalimide is completely dissolved to obtain an amidation liquid containing sodium anthranilate; and adding methanol into the amidation liquid to obtain the methanol solution of the o-formamide sodium benzoate.
4. The method for continuously preparing the methyl anthranilate according to claim 1, characterized in that the volume ratio of the methanol solution of the sodium anthranilate to the sodium hypochlorite solution is the following ratio: the sodium hypochlorite solution is 1: 1.0-2.2.
5. The method for continuously preparing methyl anthranilate according to claim 4, characterized in that the volume ratio of the methanol solution of sodium anthranilate to the sodium hypochlorite solution is the following ratio: sodium hypochlorite solution 1:1.05
6. The method for continuously preparing methyl anthranilate according to claim 1, characterized in that the concentration of phthalimide is 2.0-3.5 mol/L, or the concentration of caustic soda liquid is 2.0-4.0 mol/L, or the concentration of methanol is 8.0-11.0 mol/L, or the concentration of sodium hypochlorite solution is 10-20%.
7. The method for continuously preparing methyl anthranilate according to claim 6, characterized in that the concentration of phthalimide is 2.5mol/L, or the concentration of sodium hydroxide is 2.5mol/L, or the concentration of methanol is 10.0mol/L, or the concentration of sodium hypochlorite solution is 15%.
8. The method for continuously preparing methyl anthranilate according to claim 1, characterized in that the reaction temperature of the methanol solution of sodium anthranilate and the sodium hypochlorite solution in the tubular reactor is controlled to be-10 to 5 ℃ by the cooling medium surrounding the reaction chamber.
9. The method for continuously preparing methyl anthranilate according to claim 1, characterized in that the material discharged from the other end of the tubular reactor is hydrolyzed at 40-70 ℃.
10. The method for continuously preparing the methyl anthranilate according to claim 8, characterized in that the reaction temperature of the methanol solution of sodium anthranilate and the sodium hypochlorite solution in the tubular reactor is controlled to-5 ℃ by the cooling medium surrounding the reaction chamber, and the reaction time is 8 s.
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| CN101948400B (en) * | 2010-08-30 | 2014-06-18 | 濮阳市佳华化工有限公司 | Preparation method of methyl anthranilate |
| CN106179038B (en) * | 2016-08-31 | 2020-04-24 | 山东豪迈机械制造有限公司 | Stirring shaft capable of exchanging heat and tubular reactor |
| CN206152685U (en) * | 2016-08-31 | 2017-05-10 | 山东豪迈机械制造有限公司 | Novel interchangeable thermal agitation axle and tubular reactor |
| CN206566896U (en) * | 2017-01-10 | 2017-10-20 | 山东豪迈化工技术有限公司 | A kind of agitating device and its serialization tubular reactor |
| CN206566900U (en) * | 2017-01-25 | 2017-10-20 | 临沂远博化工有限公司 | A kind of reactor of continuous production nitromethane |
| CN110229077A (en) * | 2019-06-19 | 2019-09-13 | 深圳市一正科技有限公司 | A method of continuously preparing methyl anthranilate |
| CN210632117U (en) * | 2019-08-27 | 2020-05-29 | 青海省博鸿化工科技股份有限公司 | Continuous reaction device |
| CN110694575A (en) * | 2019-11-11 | 2020-01-17 | 山东豪迈机械制造有限公司 | Fin, stirring shaft and tubular reactor |
| CN111253271B (en) * | 2020-02-11 | 2023-02-28 | 浙江聚贤医药科技有限公司 | Method for preparing 2-amino-3-nitrobenzoic acid methyl ester |
| CN111269198A (en) * | 2020-02-18 | 2020-06-12 | 浙江工业大学 | Method for continuously preparing bentazon |
| CN111253284B (en) * | 2020-03-11 | 2023-08-04 | 青岛雪洁助剂有限公司 | Benzyl cyanide production device and process with continuous whole process |
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2020
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