CN110684010A - Method and device for synthesizing 3, 4-methylenedioxymandelic acid through emulsification catalysis - Google Patents

Abstract

The invention discloses a method for synthesizing 3,4-methylenedioxyphenylglycolic acid by adopting an emulsification catalysis process. In the method, gas is introduced into the reaction system during the preparation of mixed acid and the emulsification synthesis process, so that the reaction system is A large number of bubbles are generated, so that the surface area of the reactants is increased, the contact area between the reactants is increased, and the conversion rate and yield of the reaction can be improved. Using the homogenization effect of the emulsification process, the piperonyl ring is uniformly dispersed in the glyoxylic acid with extremely small droplets, which can improve the contact efficiency between the reactants and improve the product purity and yield. In the reaction process, the method of adding a phase transfer catalyst is used to improve the affinity between the water phase and the oil phase, and further improve the emulsification effect, thereby improving the selectivity and yield of the reaction. The invention also discloses a device for synthesizing 3,4-methylenedioxyphenylglycolic acid by emulsification and catalysis, which can realize a method for synthesizing 3,4-methylenedioxyphenylglycolic acid by adopting the emulsification catalysis process.

Description

A kind of method and device for synthesizing 3,4-methylenedioxyphenylglycolic acid by emulsification and catalysis

technical field

The invention belongs to the technical field of chemical engineering, and in particular relates to a method and a device for synthesizing 3,4-methylenedioxyphenylglycolic acid by emulsification and catalysis.

Background technique

3,4-Methylenedioxyphenylglycolic acid is an intermediate in the synthesis of piperonal. Piperonal is widely used in perfumes, spices, cherry and vanilla flavorings. The fragrance lasts for a long time. It is used as a deodorant and a fixative. It is a safe fragrance recognized by the American Fragrance Extract Manufacturing Association. It is widely used in indoor fragrances, soap flavors, food flavors and tobacco flavors. It can also be used in chemical biopharmaceuticals. It is one of the special commodities that the state implements the export license.

The traditional synthesis method of 3,4-methylenedioxyphenylglycolic acid is to use piperonyl ring and glyoxylic acid to synthesize under acidic conditions. Shan Shaojun et al. studied the reaction temperature, reaction time, glyoxylic acid and Influence of reaction factors such as the molar ratio of piperonyl rings (Shan Shaojun, Du Zhenmei. Synthesis of 3,4-methylenedioxyphenylglycolic acid [J]. Anhui Chemical Industry, 2007, 2; 46-47.). Wang Shuai et al (Wang Shuai, Li Yaoxian, Wang Hengguo. Synthesis of jasmonaldehyde by air catalytic oxidation [J]. Applied Chemical Industry, 2009, 4: 491-493.) and Zhang Kunshui et al (Zhang Kunshui, Huang Han, Chen Yisheng. Medicinal jasmonaldehyde Research on the synthetic method of silver nitrate [J]. China Modern Drug Application. 2008, 2: 53-54.) When studying the synthetic method of jasmine aldehyde, a similar preparation of 3,4-methylenedioxyphenylglycolic acid was used. . Xi Hongjuan investigated the influence of factors such as reaction temperature, catalyst concentration, raw material ratio and reaction time, and discussed the mechanism of action of sulfuric acid catalyst and the possible reaction process (Xi Hongjuan, Gao Zhixian, Wang Jianguo. Jasmine aldehyde intermediate 3,4- Synthesis and Characterization of Methylene Dioxyphenyl Glycolic Acid [J]. Chemical Research and Applications, 2009, 21: 396-400.).

The above-mentioned prior art has the following shortcomings;

Due to the high viscosity of the product 3,4-methylenedioxyphenylglycolic acid, the fluidity during the synthesis process is poor, the mass transfer efficiency is not high, and the piperonyl ring and glyoxylic acid are immiscible, and the two The contact area between the phases is small, so the reaction is insufficient, resulting in low yield, poor heat transfer effect, poor selectivity of the reaction, and many by-products.

SUMMARY OF THE INVENTION

The object of the present invention is to overcome the deficiencies of the prior art, and to provide a method and device for synthesizing 3,4-methylenedioxyphenylglycolic acid by emulsification and catalysis. The invention can improve the mixing efficiency of two-phase substances in the reaction system and improve the reaction speed, shorten the reaction time, improve the reaction yield, and reduce the amount of waste water generated during the reaction.

The present invention is achieved through the following technical solutions:

A method for synthesizing 3,4-methylenedioxyphenylglycolic acid by emulsification and catalysis, characterized in that, carry out according to the following steps:

Step 1, the mass ratio of water: 50wt% glyoxylic acid aqueous solution=1:15～20 mixture is stirred at constant temperature, the constant temperature stirring temperature is -30 ℃～-20 ℃, and the stirring speed is 350rpm～450rpm;

Step 2, after starting to stir, add dropwise 98wt% concentrated sulfuric acid to the mixture, the dropwise amount per minute is 0.03 to 0.1 times the mass of the mixture, dropwise add the total amount of the 98wt% concentrated sulfuric acid and the amount of the concentrated sulfuric acid in step 1. The mass ratio of the water is 98wt% concentrated sulfuric acid:water=12～15:1, and the stirring temperature is -30℃～-20℃;

Step 3, when all the 98wt% concentrated sulfuric acid is added dropwise, continue stirring for 20 to 40 minutes, and the stirring temperature is -30°C to -20°C;

Step 4, add 3,4-methylenedioxyphenylglycolic acid and benzyltriethylammonium chloride to the solution after step 3, add 3,4-methylenedioxyphenylglycolic acid in an amount equal to The ratio of the water mass described in step 1 is 3,4-methylenedioxyphenylglycolic acid:water=0.1～1:1, and the amount of benzyltriethylammonium chloride added is the same as the water mass described in step 1 The ratio of benzyl triethyl ammonium chloride: water = 0.5 ~ 1.5: 1;

Step 5: Emulsify the solution after step 4. The emulsification speed is 10 to 15 Kr/min. During emulsification, pepper ring is added dropwise. 3～10min;

Step 6, the step 5 is repeated many times, and the interval between each time is 3～10min, and the ratio of the total amount of pepper ring added to the water quality described in step 1 is pepper ring: water=10～15:1;

Step 7, the solution after step 6 is stirred at a constant temperature, the stirring temperature is 0°C to 10°C, the stirring rate is 400rpm to 600rpm, and the stirring time is 20min to 40min;

Step 8, adding a stop solution to the solution after the end of step 7, the ratio of the total amount of the stop solution added to the water quality in step 1 is the stop solution: water=15～30:1, and the reaction is terminated to obtain a product;

The process of steps 1 to 7 also includes a process of bubbling air into the solution, and the air volume per minute is 7 to 20 times the volume of the mixture.

In the above technical solution, in the step 1, a mixture whose mass ratio is water:50wt% aqueous glyoxylic acid=1:15～17 is stirred at a constant temperature, and the constant temperature stirring temperature is -28°C～-23°C, and the stirring rate is 380rpm～420rpm.

In the above technical solution, in the step 4, the ratio of the amount of 3,4-methylenedioxyphenylglycolic acid added to the water quality is 3,4-methylenedioxyphenylglycolic acid: water=0.1～ 0.4:1.

In the above technical solution, in the step 4, the ratio of the amount of benzyltriethylammonium chloride added to the water quality described in the step 1 is benzyltriethylammonium chloride:water=0.8-1.2:1.

In the above technical solution, in the step 5, the emulsification speed is 10-12Kr/min, the pepper ring is added dropwise during emulsification, the dripping amount per minute is 0.5-0.8 times the water quality, and the emulsification time is 5-10min.

In the above technical scheme, the step 6 and the step 5 are repeated 3 to 8 times, with an interval of 3 to 10 min between each time, and the ratio of the total amount of pepper ring added to the water quality is pepper ring: water = 10 to 12 :1.

In the above technical solution, in the step 8, the added stop solution is water, and the ratio of the total amount of the stop solution added to the water mass in step 1 is the stop solution: water = 15-25:1.

In the above technical solution, proceed according to the following steps:

Step 1, the mixture whose mass ratio is water:50wt% glyoxylic acid aqueous solution=1:14～16 is stirred at constant temperature, the constant temperature stirring temperature is -30°C～-25°C, and the stirring speed is 400rpm;

Step 2, after starting to stir, add dropwise 98wt% concentrated sulfuric acid to the mixture, the dropwise amount per minute is 0.03 to 0.07 times the mass of the mixture, add dropwise the total amount of the 98wt% concentrated sulfuric acid and the amount of the concentrated sulfuric acid in step 1. The mass ratio of the water is 98wt% concentrated sulfuric acid:water=12～14:1, and the stirring temperature is -30℃～-20℃;

Step 3, when all the 98wt% concentrated sulfuric acid is added dropwise, continue stirring for 20 to 30 minutes, and the stirring temperature is -30°C to -25°C;

Step 4, add 3,4-methylenedioxyphenylglycolic acid and benzyltriethylammonium chloride to the solution after step 3, add 3,4-methylenedioxyphenylglycolic acid in an amount equal to The mass ratio of the water described in step 1 is 3,4-methylenedioxyphenylglycolic acid:water=0.3～0.4:1, and the amount of benzyltriethylammonium chloride added is the same as that of the water described in step 1. The mass ratio is benzyltriethylammonium chloride:water=0.8～1:1;

Step 5: Emulsify the solution after step 4. The emulsification speed is 11 to 12 Kr/min. During emulsification, pepper rings are added dropwise. 3～5min;

Step 6, the step 5 is repeated for many times, and the interval between each time is 3～10min, and the mass ratio of the total amount of pepper ring added to the water described in step 1 is pepper ring: water=10～11:1;

Step 7, the solution after step 6 is stirred at a constant temperature, the stirring temperature is 0°C to 10°C, the stirring rate is 400rpm to 600rpm, and the stirring time is 20min to 40min;

Step 8, adding a stop solution to the solution after the end of step 7, the ratio of the total amount of the stop solution added to the water mass in step 1 is the stop solution: water=15～20:1, and the reaction is terminated to obtain a product;

The process of steps 1 to 7 also includes a process of blowing air into the solution, and the air volume per minute is 12 to 20 times the volume of the mixture.

In the above technical solution, the air blowing medium used in the air blowing process is nitrogen.

A device for emulsification and catalytic synthesis of 3,4-methylenedioxyphenylglycolic acid, comprising a jacketed distributor stirred tank, a sulfuric acid metering tank, a jacketed distributor emulsification tank, and a jacketed distributor product stirred tank, Pepper ring metering tank, constant temperature tank, filter equipment, feeding pump, gas storage tank, filtrate tank, the outlet of the sulfuric acid metering tank is connected with the jacketed distributor stirring tank pipeline, and the circulating liquid outlet of the constant temperature tank is connected by pipelines respectively. The jacket inlet of the jacketed distributor stirring kettle, the jacket inlet of the jacketed distributor emulsification kettle and the jacket inlet of the jacketed distributor product stirring kettle, the circulating liquid inlets of the constant temperature tank are respectively connected by pipes. The jacket outlet of the jacketed distributor stirred tank, the jacket outlet of the jacketed distributor emulsification tank and the jacket outlet of the jacketed distributor product stirred tank, the outlet of the jacketed distributor stirred tank is the same as the The inlet pipeline of the feeding pump is connected, the outlet of the pepper ring metering tank is connected with the pipeline of the jacketed distributor emulsification kettle, and the outlet of the jacketed distributor emulsification kettle is connected with the inlet pipeline of the jacketed distributor product stirring tank , the outlet of the stirred tank of the jacketed distributor product is connected with the feed port of the filter equipment, and the outlet of the gas storage tank is connected to the gas distribution pipe inlet of the stirred tank of the jacketed distributor by pipelines, The gas distribution pipe inlet of the jacketed distributor emulsification tank and the gas distribution pipe inlet of the jacketed distributor product stirring tank, and the liquid phase outlet of the filtration device is connected to the filtrate tank inlet.

In the above technical solution, both the sulfuric acid metering tank and the outlet pipe of the pepper ring metering tank are provided with flow meters.

In the above technical solution, the sulfuric acid metering tank is arranged above the jacketed distributor stirring tank, and the pepper ring metering tank is arranged above the jacketed distributor emulsification tank.

In the above technical scheme, the jacket inlet pipe of the jacketed distributor stirring tank, the jacket inlet pipe of the jacketed distributor emulsification kettle and the jacket inlet pipe of the jacketed distributor product stirring tank are all provided with Liquid flow meter.

In the above technical scheme, the gas distribution pipe inlet pipe of the jacketed distributor stirred tank, the gas distribution pipe inlet pipe of the jacketed distributor emulsification tank, and the gas distribution pipe inlet pipe of the jacketed distributor product stirred tank gas distribution pipe are all uniform. A gas flow meter is provided.

In the above technical solution, an emulsifying device and a wall scraping stirring device are provided on the jacketed distributor emulsifying kettle.

In the above technical solution, two sets of emulsifying devices and wall scraping stirring devices are arranged on the jacketed distributor emulsifying kettle.

In the above technical solution, the filtering device may be a multi-stage filtering device.

In the above technical solution, the filtering device may be a 2-stage filtering device.

In the above technical solution, temperature detection instruments are installed on both the jacketed distributor stirring kettle and the jacketed distributor emulsification kettle.

The advantages and beneficial effects of the present invention are:

1. The method for synthesizing 3,4-methylenedioxyphenylglycolic acid in the present invention adopts the method of emulsification catalysis process to synthesize, and this method feeds gas into the reaction system during the preparation of mixed acid and the emulsification synthesis process to make the reaction A large number of bubbles are generated in the system, so that the surface area of the reactants is increased, the contact area between the reactants is increased, and the conversion rate and yield of the reaction can be improved.

2. The present invention adopts the emulsification method to synthesize 3,4-methylenedioxyphenylglycolic acid, and utilizes the homogenization effect of the emulsification process in the synthesis, so that the piperonyl ring is uniformly dispersed in the acetaldehyde with very small droplets. In the acid, the contact efficiency between the reactants can be improved, and the product purity and yield can be improved.

3. The emulsifier used in the present invention is 3,4-methylenedioxyphenylglycolic acid, and the method is based on the principle that 3,4-methylenedioxyphenylglycolic acid has both lipophilic and hydrophilic groups, Using the product as an emulsifier can form a stable emulsion system without introducing substances outside the reaction system, which makes the product separation process simpler and easier.

4. The method of adding a phase transfer catalyst in the reaction process of the present invention improves the affinity between the water phase and the oil phase, and further improves the emulsification effect, thereby improving the selectivity and yield of the reaction.

Description of drawings

Fig. 1 is a kind of schematic flow diagram of emulsification catalyzed synthesis 3,4-methylenedioxyphenylglycolic acid.

FIG. 2 is a schematic diagram of Embodiment 3 of the present invention.

FIG. 3 is a schematic diagram of Embodiment 4 of the present invention.

in:

1: Jacketed distributor stirring tank, 2: Sulfuric acid metering tank, 3: Jacketed distributor emulsification tank, 4: Pepper ring metering tank, 5: Constant temperature tank, 6: Filtration equipment, 7: Feeding pump, 8: Air storage tank, 9: filtrate tank; 12: jacketed distributor product stirring tank;

6-1: Primary filtration equipment, 6-2: Secondary filtration equipment, 10-1: First gas flow meter, 10-2: Second gas flow meter, 10-3: Third gas flow meter, 11- 1: The first liquid flowmeter, 11-2: The second liquid flowmeter, 11-3: The third liquid flowmeter.

For those of ordinary skill in the art, other related drawings can be obtained from the above drawings without any creative effort.

Detailed ways

In order to make those skilled in the art better understand the solutions of the present invention, the technical solutions of the present invention are further described below with reference to specific embodiments.

Comparative ratio

1. Weigh piperonyl 100g, water 10g, 50% glyoxylic acid aqueous solution 160g, 98% concentrated sulfuric acid 140g.

2. Add 10 g of water and 160 g of 50% glyoxylic acid aqueous solution to the jacketed reactor.

3. Connect the jacketed reactor to the constant temperature tank, set the temperature of the constant temperature tank to 5°C, and run the constant temperature tank to cool down for more than half an hour until the temperature of the liquid in the jacket reaches 5°C.

4. Connect the electric stirrer, stir the liquid in the jacketed reactor with the plastic stirring blade, the speed is 400r/min

5. 140g of concentrated sulfuric acid was added dropwise with a constant pressure funnel at a constant speed, and the speed was controlled at 7g/min. After the dropwise addition, continued stirring for 30min. Get mixed acid.

6. The mixed acid, which accounts for 70% of the total mass of the mixed acid, is removed from the jacketed reactor and refrigerated in a 5°C environment.

7. Add 30 g of pepper ring dropwise to the jacketed reactor with a constant pressure funnel at a constant speed, and the speed is controlled at 3 g/min. After the dropwise addition was completed, stirring was continued for 30 min.

8. The 70% mixed acid removed in step 6 and 70 g of piperonyl ring (dropping time 0.5h) were added dropwise to the jacketed reactor with a constant pressure funnel at a constant speed.

9. After the dropwise addition, adjust the speed of the stirring device to 500r/min, and continue to stir the reaction for 35min

10. Add 200 mL of water to the jacketed reactor to stop the reaction.

11. Suction filtration with a 1L suction filtration bottle to obtain a solid, weighed, dried, and detected by liquid chromatography.

12. The tested yield is 71.42%, the purity is 68.54%, and the total yield is 44.64%.

Example 1

A method for synthesizing 3,4-methylenedioxyphenylglycolic acid by emulsification and catalysis is carried out according to the following steps:

Step 1, a mixture of 10 g of water and 160 g of a 50 wt% glyoxylic acid aqueous solution is stirred at a constant temperature, the constant temperature stirring temperature is -25°C, and the stirring speed is 400 rpm;

Step 2, after starting to stir, dropwise add 98wt% concentrated sulfuric acid to the mixture, dropwise at a rate of 7g/min per minute, add dropwise the total amount of the 98wt% concentrated sulfuric acid 140g, stirring temperature is -25 ℃, stirring speed 400rpm ;

Step 3, when all the 98wt% concentrated sulfuric acid is added dropwise, continue stirring for 30min, and the stirring temperature is -25°C;

Step 4, add 3,4-methylenedioxyphenylglycolic acid and benzyltriethylammonium chloride to the solution after step 3, and add 4g of 3,4-methylenedioxyphenylglycolic acid , add the amount of benzyl triethyl ammonium chloride 8g;

Step 5, emulsify the solution after step 4 is completed, the emulsification speed is 12Kr/min, and the pepper ring is added dropwise during emulsification at the same time, the dripping amount per minute is 5g, and the emulsification time is 5min;

Step 6, the step 5 is repeated 4 times, and the interval between each time is 3min, adding the total amount of pepper ring 100g;

Step 7, the solution after step 6 is stirred at a constant temperature, the stirring temperature is 5°C, the stirring speed is 500 rpm, and the stirring time is 30 min;

Step 8, adding 200ml of water to the solution after the end of step 7 to terminate the reaction to obtain the product;

The process of steps 1 to 7 also includes a process of bubbling into the solution, the bubbling volume per minute is 2.5 L/min, and the bubbling medium used is nitrogen.

The tested purity was 97.60%, and the total yield was 91.50%.

Example 2

A method for synthesizing 3,4-methylenedioxyphenylglycolic acid by emulsification and catalysis is carried out according to the following steps:

Step 1, a mixture of 10 g of water and 200 g of a 50 wt% glyoxylic acid aqueous solution is stirred at a constant temperature, the constant temperature stirring temperature is -30°C, and the stirring speed is 430 rpm;

Step 2, after starting to stir, add 98wt% concentrated sulfuric acid dropwise to the mixture, dropwise at a rate of 9g/min per minute, add dropwise the total amount of 98wt% concentrated sulfuric acid 150g, stirring temperature is -28 ℃, stirring speed 430rpm ;

Step 3, when all the 98wt% concentrated sulfuric acid is added dropwise, continue stirring for 30min, and the stirring temperature is -28°C;

Step 4, add 3,4-methylenedioxyphenylglycolic acid and benzyltriethylammonium chloride to the solution after step 3, add 9g of 3,4-methylenedioxyphenylglycolic acid , add the amount of benzyl triethyl ammonium chloride 13g;

Step 5: Emulsify the solution after step 4 is completed, the emulsification speed is 15Kr/min, and the pepper ring is added dropwise during emulsification, and the dripping amount per minute is 5g, and the emulsification time is 7min;

Step 6, the step 5 steps are repeated 4 times, and the interval between each time is 3min, adding the total amount of pepper ring 140g;

Step 7, the solution after step 6 is stirred at a constant temperature, the stirring temperature is 5 °C, the stirring speed is 600 rpm, and the stirring time is 30 min;

Step 8, adding 200ml of water to the solution after the end of step 7 to terminate the reaction to obtain the product;

The process of steps 1 to 7 also includes a process of bubbling into the solution, the bubbling volume per minute is 2.5 L/min, and the bubbling medium used is nitrogen.

The detected purity was 97.53%, and the total yield was 91.43%.

Example 3

A device for emulsification and catalytic synthesis of 3,4-methylenedioxyphenylglycolic acid, comprising a jacketed distributor stirred tank, a sulfuric acid metering tank, a jacketed distributor emulsification tank, and a jacketed distributor product stirred tank, Pepper ring metering tank, constant temperature tank, filtration equipment, feeding pump, gas storage tank, filtrate tank, the outlet of the sulfuric acid metering tank is connected with the jacketed distributor stirring tank pipeline, and the outlet pipe of the sulfuric acid metering tank is provided with a flow meter. The circulating liquid outlet of the constant temperature tank is respectively connected with the jacket inlet of the jacketed distributor stirring tank, the jacket inlet of the jacketed distributor emulsification tank and the jacket inlet of the jacketed distributor product stirring tank. The circulating liquid inlet of the constant temperature tank is respectively connected with the jacket outlet of the jacketed distributor stirred tank, the jacketed outlet of the jacketed distributor emulsification tank and the jacketed outlet of the jacketed distributor product stirred tank. The outlet of the stirring tank of the jacketed distributor is connected with the inlet pipeline of the feeding pump, the outlet of the pepper ring metering tank is connected with the pipeline of the emulsification kettle of the jacketed distributor, the outlet pipe of the pepper ring metering tank is provided with a flow meter, and the clamp The outlet of the emulsification kettle of the jacketed distributor is connected with the inlet pipeline of the product stirred tank of the jacketed distributor, the outlet of the stirred tank of the jacketed distributor product is connected with the pipeline of the feed inlet of the filter equipment, and the gas storage tank The outlet is respectively connected with the gas distribution pipe inlet of the jacketed distributor stirring tank, the gas distribution pipe inlet of the jacketed distributor emulsification tank and the gas distribution pipe inlet of the jacketed distributor product stirring tank, so The liquid phase outlet of the filtration device is connected to the inlet of the filtrate tank. The jacket inlet pipe of the jacketed distributor stirred tank, the jacketed inlet pipe of the jacketed distributor emulsification tank and the jacketed inlet pipe of the jacketed distributor product stirred tank are all provided with liquid flow meters. The gas distribution pipe inlet pipe of the jacketed distributor stirring tank, the gas distribution pipe inlet pipe of the jacketed distributor emulsification tank and the gas distribution pipe inlet pipe of the jacketed distributor product stirring tank are all provided with gas flow meters. . Two sets of emulsification devices and wall scraping stirring devices are arranged on the jacketed distributor emulsification kettle. Temperature detection instruments are installed on both the jacketed distributor stirring kettle and the jacketed distributor emulsification kettle.

Example 4

A device for emulsification and catalytic synthesis of 3,4-methylenedioxyphenylglycolic acid, comprising a jacketed distributor stirred tank, a sulfuric acid metering tank, a jacketed distributor emulsification tank, and a jacketed distributor product stirred tank, Pepper ring metering tank, constant temperature tank, two-stage filtration equipment, feeding pump, gas storage tank, filtrate tank, the outlet of the sulfuric acid metering tank is connected to the jacketed distributor stirring tank pipeline, and the outlet pipe of the sulfuric acid metering tank is provided with a flow meter, The circulating liquid outlet of the constant temperature tank is respectively connected with the jacket inlet of the jacketed distributor stirring tank, the jacket inlet of the jacketed distributor emulsification tank and the jacket inlet of the jacketed distributor product stirring tank, respectively. The circulating liquid inlet of the constant temperature tank is respectively connected with the jacket outlet of the jacketed distributor stirred tank, the jacketed outlet of the jacketed distributor emulsification tank and the jacketed outlet of the jacketed distributor product stirred tank, respectively. The outlet of the jacketed distributor stirring tank is connected with the inlet pipeline of the feeding pump, the outlet of the pepper ring metering tank is connected with the pipeline of the jacketed distributor emulsification kettle, and the outlet pipe of the pepper ring metering tank is provided with a flow meter, so The outlet of the emulsification kettle of the jacketed distributor is connected with the inlet pipeline of the product stirred tank of the jacketed distributor, and the outlet of the stirred tank of the jacketed distributor product is connected with the pipeline of the feed inlet of the primary filtration equipment, so The discharge port of the primary filtration equipment is connected with the feed port of the secondary filtration equipment, and the outlet of the gas storage tank is connected to the gas distribution pipe inlet and the gas distribution pipe of the jacketed distributor stirring tank respectively by pipes. The gas distribution pipe inlet of the jacketed distributor emulsification kettle and the gas distribution pipe inlet of the jacketed distributor product stirring tank, and the liquid phase outlet of the secondary filtration device is connected to the filtrate tank inlet. The jacket inlet pipe of the jacketed distributor stirred tank, the jacketed inlet pipe of the jacketed distributor emulsification tank and the jacketed inlet pipe of the jacketed distributor product stirred tank are all provided with liquid flow meters. The gas distribution pipe inlet pipe of the jacketed distributor stirring tank, the gas distribution pipe inlet pipe of the jacketed distributor emulsification tank and the gas distribution pipe inlet pipe of the jacketed distributor product stirring tank are all provided with gas flow meters. . Two sets of emulsification devices and wall scraping stirring devices are arranged on the jacketed distributor emulsification kettle. Temperature detection instruments are installed on both the jacketed distributor stirring kettle and the jacketed distributor emulsification kettle.

The primary filtration equipment and the secondary filtration equipment use filter media of different precision. The filter media used in the primary filtration equipment has a larger pore size, which can filter out the products with larger particle size in the product system, and the filtrate enters the secondary filtration equipment. The grade filtration equipment adopts the filter medium with small pore size, which can filter out the final product 3,4-methylenedioxyphenylglycolic acid with small particle size, and the product recovery is more sufficient.

The present invention has been exemplarily described above. It should be noted that, without departing from the core of the present invention, any simple deformation, modification, or other equivalent replacements that can be performed by those skilled in the art without any creative effort fall into the scope of the present invention. the scope of protection of the invention.

Claims (10)

1. A method for synthesizing 3, 4-methylenedioxymandelic acid by emulsification catalysis is characterized by comprising the following steps:

step 1, mixing water in a mass ratio: 50 wt% glyoxylic acid aqueous solution ═ 1: stirring the mixture of 15-20 at constant temperature, wherein the constant temperature stirring temperature is-30 ℃ to-20 ℃, and the stirring speed is 350rpm to 450 rpm;

step 2, after stirring, dripping 98 wt% of concentrated sulfuric acid into the mixture, wherein the dripping amount per minute is 0.03-0.1 time of the mass of the mixture, and the ratio of the total mass of the 98 wt% of concentrated sulfuric acid to the mass of the water in the step 1 is 98 wt% of concentrated sulfuric acid: 12-15% of water: 1, stirring at-30 to-20 ℃;

step 3, after all the 98 wt% concentrated sulfuric acid is dripped, continuously stirring for 20-40 min at the stirring temperature of minus 30-minus 20 ℃;

step 4, adding 3, 4-methylenedioxymandelic acid and benzyltriethylammonium chloride into the solution after the step 3 is completed, wherein the ratio of the added 3, 4-methylenedioxymandelic acid to the water mass in the step 1 is 3, 4-methylenedioxymandelic acid: water is 0.1-1: 1, adding benzyltriethylammonium chloride in a mass ratio of benzyltriethylammonium chloride to the water in the step 1: 0.5-1.5% of water: 1;

step 5, emulsifying the solution obtained in the step 4 at an emulsifying speed of 10-15 Kr/min, dripping pepper rings at the same time during emulsification, wherein the dripping amount per minute is 0.1-1 time of the mass of the water obtained in the step 1, and the emulsifying time is 3-10 min;

step 6, repeating the step 5 for multiple times, wherein the interval between every two times is 3-10 min, and the ratio of the total amount of added piperonyl butoxide to the mass of the water in the step 1 is piperonyl butoxide: water is 10-15: 1;

step 7, stirring the solution obtained after the step 6 at a constant temperature of 0-10 ℃, at a stirring speed of 400-600 rpm for 20-40 min;

step 8, adding a stop solution into the solution after the step 7 is finished, wherein the ratio of the total amount of the stop solution to the water mass in the step 1 is the stop solution: 15-30% of water: 1, terminating the reaction to obtain a product;

and the processes of the step 1 to the step 7 also comprise a process of blowing gas into the solution, wherein the gas blowing amount per minute is 7-20 times of the volume of the mixture.

2. The method for emulsion catalytic synthesis of 3, 4-methylenedioxymandelic acid according to claim 1, wherein in step 1, the ratio of water: 50 wt% glyoxylic acid aqueous solution ═ 1: 15-17, stirring at a constant temperature of-28 to-23 ℃ and at a stirring speed of 380 to 420 rpm.

3. The emulsion-catalyzed synthesis method of 3, 4-methylenedioxymandelic acid according to claim 1, wherein in step 4, the ratio of the amount of 3, 4-methylenedioxymandelic acid added to the mass of water is 3, 4-methylenedioxymandelic acid: water is 0.1-0.4: 1.

4. the method for emulsion catalytic synthesis of 3, 4-methylenedioxymandelic acid according to claim 1, wherein the ratio of the amount of benzyltriethylammonium chloride added in step 4 to the mass of water in step 1 is benzyltriethylammonium chloride: water is 0.8-1.2: 1.

5. the method for the emulsion catalytic synthesis of 3, 4-methylenedioxymandelic acid according to claim 1, wherein in step 5, the emulsion speed is 10-12 Kr/min, pepper rings are added dropwise during the emulsion, the amount of the added pepper rings is 0.5-0.8 times of the mass of the water per minute, and the emulsion time is 5-10 min.

6. The method for synthesizing 3, 4-methylenedioxymandelic acid by emulsion catalysis as claimed in claim 1, wherein in step 6, step 5 is repeated 3-8 times, each time with an interval of 3-10 min, and the ratio of the total amount of piperonyl to the mass of water is piperonyl: water is 10-12: 1.

7. the method for synthesizing 3, 4-methylenedioxymandelic acid by emulsion catalysis according to claim 1, wherein in step 8, the stop solution is added as water, and the ratio of the total amount of the stop solution added to the mass of the water in step 1 is stop solution: 15-25% of water: 1.

8. the emulsion-catalyzed synthesis of 3, 4-methylenedioxymandelic acid according to claim 1, comprising the steps of:

step 1, mixing water in a mass ratio: 50 wt% glyoxylic acid aqueous solution ═ 1: stirring the mixture of 14-16 at constant temperature, wherein the constant temperature stirring temperature is-30 ℃ to-25 ℃, and the stirring speed is 400 rpm;

step 2, after stirring, dripping 98 wt% of concentrated sulfuric acid into the mixture, wherein the dripping amount per minute is 0.03-0.07 time of the mass of the mixture, and the mass ratio of the total mass of the 98 wt% of concentrated sulfuric acid to the water in the step 1 is 98 wt% of concentrated sulfuric acid: 12-14% of water: 1, stirring at-30 to-20 ℃;

step 3, after all the 98 wt% concentrated sulfuric acid is dripped, continuously stirring for 20-30 min at the stirring temperature of minus 30-minus 25 ℃;

and 4, adding 3, 4-methylenedioxybenzene glycolic acid and benzyltriethylammonium chloride into the solution after the step 3 is completed, wherein the mass ratio of the added 3, 4-methylenedioxybenzene glycolic acid to the water in the step 1 is 3, 4-methylenedioxybenzene glycolic acid: water is 0.3-0.4: 1, adding benzyltriethylammonium chloride in a mass ratio of benzyltriethylammonium chloride to water in the step 1: water is 0.8-1: 1;

step 5, emulsifying the solution obtained in the step 4 at an emulsifying speed of 11-12 Kr/min, and simultaneously dripping pepper rings at a dripping amount of 0.5-0.6 time of the mass of the water obtained in the step 1 per minute for 3-5 min;

step 6, repeating the step 5 for multiple times, wherein the interval between every two times is 3-10 min, and the mass ratio of the total amount of the added piperonyl butoxide to the water in the step 1 is: water is 10-11: 1;

step 7, stirring the solution obtained after the step 6 at a constant temperature of 0-10 ℃, at a stirring speed of 400-600 rpm for 20-40 min;

step 8, adding a stop solution into the solution after the step 7 is finished, wherein the ratio of the total amount of the stop solution to the water mass in the step 1 is the stop solution: 15-20% of water: 1, terminating the reaction to obtain a product;

the processes of the step 1 to the step 7 also comprise a process of blowing gas into the solution, wherein the gas blowing amount per minute is 12-20 times of the volume of the mixture.

9. The method for synthesizing 3, 4-methylenedioxymandelic acid by emulsion catalysis according to any one of claims 1 to 8, wherein the air-blowing medium used in the air-blowing process is nitrogen.

10. A device for synthesizing 3, 4-methylenedioxymandelic acid by emulsification and catalysis is characterized by comprising a jacketed distributor stirred tank, a sulfuric acid metering tank, a jacketed distributor emulsified tank, a jacketed distributor product stirred tank, a pepper ring metering tank, a thermostatic tank, a filtering device, a feeding pump, an air storage tank and a filtrate tank, wherein an outlet of the sulfuric acid metering tank is connected with a jacketed distributor stirred tank pipeline, a circulating liquid outlet of the thermostatic tank is respectively connected with a jacket inlet of the jacketed distributor stirred tank, a jacket inlet of the jacketed distributor emulsified tank and a jacket inlet of the jacketed distributor product stirred tank by pipelines, a circulating liquid inlet of the thermostatic tank is respectively connected with a jacket outlet of the jacketed distributor stirred tank, a jacket outlet of the jacketed distributor emulsified tank and a jacket outlet of the jacketed distributor product stirred tank by pipelines, the export of jacketed distributor stirred tank links to each other with the inlet pipeline of charge pump, the export of pepper ring metering tank links to each other with jacketed distributor emulsification cauldron pipeline, jacketed distributor emulsification cauldron export with jacketed distributor product stirring cauldron inlet pipeline links to each other, jacketed distributor product stirring cauldron export with filtration equipment's feed inlet pipe connection, the export of gas holder adopts the pipe connection respectively jacketed distributor stirred tank's gas distribution pipe entry the gas distribution pipe entry and the jacketed distributor product stirring cauldron gas distribution pipe entry of jacketed distributor emulsification cauldron, filtration equipment liquid phase exit linkage the filter tank entry.

Images