System for preparing 3-hydroxy-4-methoxycinnamaldehyde based on mother liquor

Abstract

This utility model relates to the field of compound preparation technology, specifically to a system for preparing 3-hydroxy-4-methoxycinnamicaldehyde based on mother liquor. The apparatus includes: a cryo-crystallization vessel, a centrifuge, a mother liquor collection tank, a water recovery vessel, a condenser, and a mother liquor water collection tank. The cryo-crystallization vessel freezes and crystallizes a reaction mixture containing 3-hydroxy-4-methoxycinnamicaldehyde, then centrifuges it to obtain mother liquor and 3-hydroxy-4-methoxycinnamicaldehyde crystals. The mother liquor is collected and then passed into the water recovery vessel for vacuum distillation. The distillate from the water recovery vessel is condensed by the condenser and sent to the mother liquor water collection tank. The second outlet of the water recovery vessel is connected to the inlet of the cryo-crystallization vessel to transfer the residual liquid from the water recovery vessel to the cryo-crystallization vessel for further cryo-crystallization, followed by centrifugation to obtain 3-hydroxy-4-methoxycinnamicaldehyde crystals.

Description

Technical Field

[0001] This invention relates to the field of compound preparation technology, specifically to a system for preparing 3-hydroxy-4-methoxycinnamonaldehyde based on mother liquor. Background Technology

[0002] In the preparation of chemical products, the efficient separation and recovery of reaction products directly affects production efficiency and environmental costs. 3-Hydroxy-4-methoxycinnamonaldehyde is an important compound widely used in fragrances, pharmaceutical intermediates, and other fields. It can be obtained by the aldol condensation reaction of isovanillin and acetaldehyde under strongly alkaline conditions, followed by freeze recrystallization and centrifugation. Subsequent freeze recrystallization and centrifugation separate the 3-hydroxy-4-methoxycinnamonaldehyde product from the mother liquor.

[0003] In some scenarios, a single-reactor refrigerated centrifugation process is commonly used to separate 3-hydroxy-4-methoxycinnamicaldehyde crystals from the mother liquor in a reaction mixture of isenhanyl and acetaldehyde under strongly alkaline conditions. This process involves freezing the reaction mixture to below 10°C before centrifugation to separate the 3-hydroxy-4-methoxycinnamicaldehyde product from the mother liquor. However, due to the limitations of single-reactor operation in terms of scale and efficiency, approximately 3%-5% of the 3-hydroxy-4-methoxycinnamicaldehyde in the mother liquor is lost due to insufficient crystallization or incomplete separation. Therefore, during centrifugation, this 3%-5% cannot be effectively recovered and directly enters the wastewater treatment process. This not only reduces the yield of 3-hydroxy-4-methoxycinnamicaldehyde, resulting in raw material waste, but also increases the load and cost of wastewater treatment. Utility Model Content

[0004] To address the technical problem of low yield of 3-hydroxy-4-methoxycinnamate, which increases the load and cost of wastewater treatment, this invention aims to provide a system for preparing 3-hydroxy-4-methoxycinnamate based on mother liquor. The specific technical solution adopted is as follows:

[0005] In a first aspect, this utility model discloses a system for preparing 3-hydroxy-4-methoxycinnamicaldehyde based on mother liquor, comprising: a freeze crystallization kettle, a centrifuge, a mother liquor collection tank, a distillation recovery kettle, a condenser, and a mother liquor distillation recovery tank; the outlet of the freeze crystallization kettle is connected to the inlet of the centrifuge, and the freeze crystallization kettle freezes and crystallizes the reaction mixture containing 3-hydroxy-4-methoxycinnamicaldehyde before centrifuging it in the centrifuge to obtain mother liquor and 3-hydroxy-4-methoxycinnamicaldehyde crystals; the inlet of the mother liquor collection tank is connected to the outlet of the centrifuge, and the outlet of the mother liquor collection tank is connected to the distillation recovery tank. The inlet of the water recovery vessel is connected to collect the mother liquor before it is fed into the distillation water recovery vessel for vacuum distillation. The first outlet of the distillation water recovery vessel is connected to the inlet of the condenser, and the outlet of the condenser is connected to the inlet of the mother liquor distillation water collection tank. The distillate from the distillation water recovery vessel is condensed by the condenser and then sent to the mother liquor distillation water collection tank. The second outlet of the distillation water recovery vessel is connected to the inlet of the freeze crystallization vessel. The residual liquid after distillation in the distillation water recovery vessel is transferred to the freeze crystallization vessel for freeze crystallization again, and then transferred to a centrifuge for centrifugation again to obtain 3-hydroxy-4-methoxycinnamicaldehyde crystals.

[0006] Optionally, the system also includes: a mother liquor pump; a discharge port is provided at the bottom of the mother liquor collection tank, and the discharge port of the mother liquor collection tank is connected to the inlet of the mother liquor pump through a first pipe; a feed port is provided at the top of the distilled water recovery vessel, and the outlet of the mother liquor pump is connected to the feed port of the distilled water recovery vessel through a second pipe; both the first pipe and the second pipe are β-homopolymer polypropylene pipes.

[0007] Optionally, the discharge port of the freeze crystallizer is located at the bottom of the freeze crystallizer, the inlet of the centrifuge is located at the top of the centrifuge, and the centrifuge is located below the freeze crystallizer. The discharge port of the freeze crystallizer and the inlet of the centrifuge are connected through a third pipe, which is a β-homopolymer polypropylene pipe.

[0008] Optionally, the inlet of the mother liquor collection tank is located at the top of the mother liquor collection tank, and the outlet of the centrifuge is located on one side of the bottom of the centrifuge. The inlet of the mother liquor collection tank and the outlet of the centrifuge are connected through a fourth pipe, and the mother liquor collection tank is located below the centrifuge. The fourth pipe is a β-homogeneous polypropylene pipe.

[0009] Optionally, the first discharge port of the steam water recovery vessel is located at the top of the steam water recovery vessel, the inlet of the condenser is located at the top of the condenser, the first discharge port of the steam water recovery vessel is connected to the inlet through a fifth pipe, and the condenser is located above the steam water recovery vessel. The fifth pipe is a steel-lined PTFE pipe.

[0010] Optionally, the discharge port of the condenser is located at the bottom of the condenser, the inlet of the mother liquor distillation collection tank is located at the top of the mother liquor distillation collection tank, the discharge port of the condenser and the inlet of the mother liquor distillation collection tank are connected through a sixth pipe, and the condenser is located above the mother liquor distillation collection tank.

[0011] Optionally, the second outlet of the water recovery vessel is located at the bottom of the water recovery vessel, and the inlet of the freezing crystallization vessel is located at the top of the freezing crystallization vessel. The second outlet of the water recovery vessel and the inlet of the freezing crystallization vessel are connected through a seventh pipe, which is a β-homopolymer polypropylene pipe.

[0012] Optionally, the outlet of the mother liquor distillation collection tank is located below the mother liquor distillation collection tank, and the outlet of the mother liquor distillation collection tank is connected to the environmental protection treatment equipment through the eighth pipe so that the liquid in the mother liquor distillation collection tank can be treated by the environmental protection treatment equipment.

[0013] Optionally, the temperature in the water recovery vessel is between 65°C and 75°C.

[0014] Optionally, the temperature in the freeze crystallizer is below 10°C.

[0015] The technical solution disclosed in this utility model embodiment allows for precise temperature control in the cryo-crystallization reactor, promoting the crystallization of 3-hydroxy-4-methoxycinnamonaldehyde from the reaction mixture. Subsequently, a centrifuge uses centrifugal force to completely separate the mother liquor from the 3-hydroxy-4-methoxycinnamonaldehyde crystals, minimizing mother liquor residue and significantly improving the purity of the 3-hydroxy-4-methoxycinnamonaldehyde crystals, resulting in high-quality 3-hydroxy-4-methoxycinnamonaldehyde. A mother liquor collection tank collects the mother liquor separated by the centrifuge and then transfers it to a distillation recovery reactor. The distillation recovery reactor performs vacuum distillation on the mother liquor, and the solvents and other components are condensed and stored in the mother liquor distillation collection tank, reducing waste discharge, environmental pollution, and the load and cost of wastewater treatment. The distillation residue is returned to the cryo-crystallization reactor for further cryo-crystallization and centrifugation to extract any remaining 3-hydroxy-4-methoxycinnamonaldehyde crystals, increasing the yield of the 3-hydroxy-4-methoxycinnamonaldehyde product, avoiding raw material waste, and reducing production costs. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a system for preparing 3-hydroxy-4-methoxycinnamic aldehyde based on mother liquor, provided for an embodiment of this utility model. Detailed Implementation

[0017] To further illustrate the technical means and effects adopted by this utility model to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a system for preparing 3-hydroxy-4-methoxycinnamic aldehyde based on mother liquor according to this utility model. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The specific details of a system for preparing 3-hydroxy-4-methoxycinnamic aldehyde based on mother liquor, provided by this invention, are described below with reference to the accompanying drawings.

[0019] like Figure 1 As shown, Figure 1 This is a schematic diagram of a system for preparing 3-hydroxy-4-methoxycinnamic aldehyde based on mother liquor, as disclosed in an embodiment of the present invention. The device includes: a freeze crystallization vessel 101, a centrifuge 102, a mother liquor collection tank 103, a water distillation recovery vessel 105, a condenser 106, and a mother liquor water distillation collection tank 107.

[0020] The outlet of the freeze crystallizer 101 is connected to the inlet of the centrifuge 102. After the reaction mixture containing 3-hydroxy-4-methoxycinnamicaldehyde is freeze crystallized in the freeze crystallizer 101, it is placed in the centrifuge 102 for centrifugation to obtain mother liquor and 3-hydroxy-4-methoxycinnamicaldehyde crystals.

[0021] The inlet of the mother liquor collection tank 103 is connected to the outlet of the centrifuge 102, and the outlet of the mother liquor collection tank 103 is connected to the inlet of the water distillation recovery kettle 105, so that the mother liquor is collected and then fed into the water distillation recovery kettle 105 for vacuum distillation.

[0022] The first outlet of the water distillation recovery vessel 105 is connected to the inlet of the condenser 106, and the outlet of the condenser 106 is connected to the inlet of the mother liquor distillation collection tank 107, so that the effluent after distillation in the water distillation recovery vessel 105 is condensed by the condenser 106 and sent to the mother liquor distillation collection tank 107.

[0023] The second outlet of the water distillation recovery vessel 105 is connected to the inlet of the freeze crystallization vessel 101 so that the residual liquid after distillation in the water distillation recovery vessel 105 is transferred to the freeze crystallization vessel 101 for freeze crystallization again, and then transferred to the centrifuge 102 for centrifugation again to obtain 3-hydroxy-4-methoxycinnamonaldehyde crystals.

[0024] Specifically, in this embodiment of the invention, the cryo-crystallization vessel 101 performs cryo-crystallization on a reaction mixture containing 3-hydroxy-4-methoxycinnamicaldehyde to precipitate 3-hydroxy-4-methoxycinnamicaldehyde crystals. A thermometer can be installed on the top of the cryo-crystallization vessel 101 to monitor the temperature TI of the material inside the vessel, ensuring precise temperature control within the range required by the crystallization process. Similarly, a pressure monitoring instrument is installed on the top of the cryo-crystallization vessel 101 to monitor the pressure PI inside the vessel, ensuring that the cryo-crystallization vessel 101 operates within a safe pressure range and avoiding the risk of overpressure. The cryo-crystallization vessel 101 is also equipped with a pressure display instrument PG to intuitively display the pressure value inside the vessel, facilitating quick reading by operators. The cryo-crystallization vessel 101 also includes a low-temperature medium channel (…). Figure 1 The RWS section (located in the middle) is used to introduce low-temperature frozen brine into the freeze crystallization vessel 101 to achieve cooling. In an optional embodiment of this invention, the temperature in the freeze crystallization vessel 101 is below 10°C to improve crystallization efficiency. The reaction mixture containing 3-hydroxy-4-methoxycinnamicaldehyde is frozen to 10°C in the freeze crystallization vessel 101 for crystallization. Then, the bottom valve of the freeze crystallization vessel 101 is opened to discharge the material into the centrifuge 102 for centrifugation, using centrifugal force to separate the 3-hydroxy-4-methoxycinnamicaldehyde crystals from the mother liquor.

[0025] Furthermore, as an optional embodiment of this utility model, the discharge port of the freeze crystallizer 101 is located at the bottom of the freeze crystallizer 101, and the inlet of the centrifuge 102 is located at the top of the centrifuge 102, with the centrifuge 102 positioned below the freeze crystallizer 101. The discharge port of the freeze crystallizer 101 and the inlet of the centrifuge 102 are connected by a third pipe, which is a β-homopolymer polypropylene pipe. The discharge port of the freeze crystallizer 101 is designed at the bottom, while the inlet of the centrifuge 102 is located at the top, and the centrifuge 102 is positioned below the freeze crystallizer 101, forming a gravity-fed conveying system. This layout fully utilizes gravity, eliminating the need for additional pumping equipment, and smoothly conveys the mixture in the freeze crystallizer 101 to the centrifuge 102, reducing energy consumption and equipment investment costs. Simultaneously, it reduces the damage to the crystal structure caused by the shear force generated during mechanical pumping, ensuring crystal integrity. The two are connected by a third pipe made of β-homogeneous polypropylene (β-HPP), which is resistant to chemical corrosion and can effectively resist the acid and alkali substances that may be encountered during the production of 3-hydroxy-4-methoxycinnamic aldehyde, thus extending the service life of the pipe. At the same time, β-HPP pipe has good low-temperature toughness and maintains excellent impact resistance even in the low-temperature environment of the freeze crystallizer 101, preventing the pipe from becoming brittle and ensuring the safety and stability of material transportation.

[0026] Furthermore, a level gauge LG, a pressure gauge PC, and a temperature sensor LT are installed in the mother liquor collection tank 103 to monitor the liquid level, pressure, and temperature within the mother liquor collection tank 103. The mother liquor after passing through the centrifuge 102 enters the mother liquor collection tank 103 for collection. In one optional embodiment of this invention, the inlet of the mother liquor collection tank 103 is located at the top of the mother liquor collection tank 103, and the outlet of the centrifuge 102 is located on one side of the bottom of the centrifuge 102. The inlet of the mother liquor collection tank 103 and the outlet of the centrifuge 102 are connected by a fourth pipe, and the mother liquor collection tank 103 is located below the centrifuge 102. The fourth pipe is a β-homopolymer polypropylene pipe. Thus, the inlet of the mother liquor collection tank 103 is located at the top, while the outlet of the centrifuge 102 is located at the bottom. The mother liquor collection tank 103 is installed directly below the centrifuge 102, and the two are connected by a fourth pipe, forming a gravity-driven conveying system. This system continues the natural flow of gravity, allowing the mother liquor separated by the centrifuge 102 to be quickly and smoothly introduced into the mother liquor collection tank 103 without the need for additional power equipment. This not only reduces energy costs but also avoids the risk of mother liquor delivery interruption due to pump equipment failure, ensuring production continuity. The fourth pipe is made of β-homogeneous polypropylene (β-HPP). The mother liquor typically contains uncrystallized target material, reaction solvents, and a small amount of impurities, and may have corrosive properties and poor low-temperature fluidity. β-HPP pipes are resistant to potential acid and alkali corrosion in the mother liquor, and their surface is not easily penetrated or corroded by chemicals in the mother liquor, effectively preventing scaling and perforation on the inner wall of the pipe and extending its service life. In low-temperature environments, the low-temperature toughness of β-HPP pipes ensures that they maintain good flexibility and impact resistance even at -20℃. Even if the viscosity of the mother liquor increases due to temperature decreases during transportation, it can prevent the pipe from cracking due to stress concentration. This ensures the reliability and safety of mother liquor collection.

[0027] Furthermore, the mother liquor in the mother liquor collection tank is fed into the distillation recovery vessel 105, which can perform vacuum distillation on the mother liquor. The distilled effluent enters the condenser 106, while the residual liquid can be fed back into the freeze crystallization vessel 101 for recycling. The top of the water distillation recovery vessel 105 is equipped with a thermometer to detect the internal temperature TI, precisely controlling the heating / condensation temperature during the distillation process to ensure distillation efficiency and product quality. The top of the vessel is also equipped with a pressure gauge to detect the internal pressure PI, precisely controlling the negative pressure environment to prevent overpressure / insufficient negative pressure from affecting the distillation effect. The vessel also features a pressure display instrument to visually present the internal pressure value PG, indicating whether the pressure is stable. Furthermore, the vessel is equipped with a temperature control system TS, which is linked to the heating supply system and can automatically start, stop, and adjust according to temperature thresholds to ensure stable distillation temperature. The vessel also features a temperature regulating valve TV to control the temperature / flow rate of the distillation product (such as steam), ensuring effective subsequent condensation. Finally, the vessel is equipped with a pressure regulating valve XY for on / off switching and fine-tuning, working together to achieve the vacuum / pressure environment for reduced pressure distillation and stable product delivery.

[0028] Furthermore, as an optional embodiment of this utility model, the device further includes: a mother liquor pump 104; a discharge port is provided at the bottom of the mother liquor collection tank 103, and the discharge port of the mother liquor collection tank 103 is connected to the inlet of the mother liquor pump 104 through a first pipe; a feed port is provided at the top of the distillation recovery kettle 105, and the outlet of the mother liquor pump 104 is connected to the feed port of the distillation recovery kettle 105 through a second pipe; both the first pipe and the second pipe are β-homopolymer polypropylene pipes. Thus, the discharge port at the bottom of the mother liquor collection tank 103 serves as the starting point, connected to the inlet of the mother liquor pump 104 through the first pipe; the outlet of the mother liquor pump 104 is connected to the second pipe, providing stable power support to ensure that the mother liquor can continuously and controllably enter the distillation recovery kettle 105, preparing for the vacuum distillation stage and improving the stability and reliability of mother liquor transmission. β-HPP pipes can withstand the erosion of various substances in the mother liquor, preventing corrosion or scaling on the inner wall of the pipe. At the same time, its low-temperature toughness can maintain the flexibility of the pipe even in the low-temperature environment where the mother liquor may be present, preventing the risk of pipe rupture caused by increased viscosity and poor flowability of the mother liquor.

[0029] Furthermore, as an optional embodiment of this utility model, the first discharge port of the water distillation recovery vessel 105 is located at the top of the water distillation recovery vessel 105, and the inlet of the condenser 106 is located at the top of the condenser 106. The first discharge port of the water distillation recovery vessel 105 is connected to the inlet through a fifth pipe, and the condenser 106 is located above the water distillation recovery vessel 105. The fifth pipe is a steel-lined PTFE pipe. In this way, the first discharge port of the water distillation recovery vessel 105 is located at the top, and the inlet of the condenser 106 is also located at the top. The condenser 106 is installed above the water distillation recovery vessel 105, and the two are connected through the fifth pipe. Utilizing the physical properties of the distillation product (steam) - the tendency of steam to flow upwards - the high-temperature steam (usually containing recyclable solvents, water, etc.) formed in the water distillation recovery vessel 105 can naturally rise to the top discharge port, and then flow smoothly into the inlet of the condenser 106 above through the fifth pipe. No additional power equipment is required for auxiliary transportation, reducing energy consumption and equipment maintenance costs. The fifth pipeline is made of steel lined with PTFE. The steam generated during distillation may contain various corrosive substances, such as acidic solvents, alkaline residues, or strong oxidizing components, which easily corrode and damage ordinary metal pipelines. However, the steel-lined PTFE pipeline combines the high strength of steel with the excellent corrosion resistance of PTFE. The inner PTFE coating effectively resists the erosion of almost all strong acids, strong alkalis, and strong oxidants. Even in high-temperature environments (long-term operating temperature can reach -200℃ to 260℃), it maintains stable chemical properties, preventing pipeline corrosion and perforation, and ensuring the safety and reliability of the steam transportation process. In one optional embodiment of this invention, the temperature in the water recovery vessel 105 is maintained between 65℃ and 75℃. 3-Hydroxy-4-methoxycinnamicaldehyde may undergo side reactions such as oxidation and degradation at high temperatures. Controlling the temperature of the water recovery vessel 105 at 65℃ to 75℃ reduces the risk of 3-hydroxy-4-methoxycinnamicaldehyde remaining in the mother liquor deteriorating due to high temperatures. When the residual liquid after distillation is transferred back to the freeze crystallizer 101 for recrystallization, the structure of 3-hydroxy-4-methoxycinnamonaldehyde remains stable, thereby improving the quality and yield of the final 3-hydroxy-4-methoxycinnamonaldehyde crystals and reducing product loss caused by high temperature.

[0030] Furthermore, as an optional embodiment of this utility model, the second discharge port of the water recovery vessel 105 is located at the bottom of the water recovery vessel 105, and the inlet of the freezing crystallization vessel 101 is located at the top of the freezing crystallization vessel 101. The second discharge port of the water recovery vessel 105 and the inlet of the freezing crystallization vessel 101 are connected by a seventh pipe, which is a β-homopolymer polypropylene pipe. After the residual liquid is transferred into the freezing crystallization vessel 101, it is cooled and frozen again to 10°C and then transferred to the centrifuge 102 for centrifugation, resulting in the secondary precipitation of 3-hydroxy-4-methoxycinnamicaldehyde crystals, thereby achieving the purpose of recovering 3-hydroxy-4-methoxycinnamicaldehyde from the mother liquor. In this way, 3-hydroxy-4-methoxycinnamicaldehyde in the residual liquid can be recovered by secondary crystallization, reducing raw material waste and increasing product yield; reducing production costs by reducing the input of new raw materials through recycling; and the long life and low maintenance characteristics of the β-homopolymer polypropylene pipe (β-HPP) reduce equipment replacement and maintenance costs, achieving stable and reliable residual liquid transportation.

[0031] Furthermore, the effluent, after being condensed by the condenser 106, forms a liquid and enters the mother liquor distillation collection tank 107. In one optional embodiment of this invention, the outlet of the condenser 106 is located at the bottom of the condenser 106, and the inlet of the mother liquor distillation collection tank 107 is located at the top of the mother liquor distillation collection tank 107. The outlet of the condenser 106 and the inlet of the mother liquor distillation collection tank 107 are connected by a sixth pipe, and the condenser 106 is positioned above the mother liquor distillation collection tank 107. The connection between the condenser 106 and the mother liquor distillation collection tank 107 via the sixth pipe, the outlet of the condenser 106 being located at the bottom, and the inlet of the mother liquor distillation collection tank 107 being located at the top, with the condenser 106 vertically mounted above the collection tank, form a gravity-driven flow channel. The "top cooling, bottom collection" layout design allows the solvent or water liquefied by cooling in the condenser 106 to automatically flow into the mother liquor distillate collection tank 107 under gravity, eliminating the need for additional pumping equipment. This reduces energy costs and avoids problems such as liquid disturbance and foam generation that may occur with mechanical transportation, ensuring the purity and stability of the recovered liquid. Furthermore, the sixth pipeline can be made of highly corrosion-resistant 316L stainless steel, which has a high chromium and nickel content, effectively resisting acid and alkali corrosion and preventing rust and perforation of the inner wall of the pipeline, ensuring the reliability of liquid transmission.

[0032] Furthermore, as an optional embodiment of this utility model, the outlet of the mother liquor distillation collection tank 107 is located below the mother liquor distillation collection tank 107, and the outlet of the mother liquor distillation collection tank 107 is connected to the environmental protection treatment equipment through the eighth pipe, so as to treat the liquid in the mother liquor distillation collection tank 107 through the environmental protection treatment equipment.

[0033] Specifically, the environmental protection treatment equipment in this embodiment includes, but is not limited to, a neutralization reaction device and a membrane treatment device. The liquid in the mother liquor distillation collection tank 107 may be acidic or alkaline. The neutralization reaction device adjusts the pH of the wastewater to a neutral range of 6-9 by adding acid-base adjusters (such as sodium hydroxide or sulfuric acid), preventing acidic or alkaline wastewater from corroding subsequent treatment equipment while meeting the acidity and alkalinity requirements of discharge standards. Membrane treatment equipment, such as reverse osmosis (RO) membranes and ultrafiltration (UF) membrane devices, utilizes the selective permeation principle of membranes to separate dissolved organic matter, heavy metal ions, and other pollutants from the wastewater. Reverse osmosis membranes can retain substances with molecular weights smaller than 0.0001 μm, effectively removing salts and most organic matter, resulting in treated water that meets high standards. Furthermore, for residual organic solvents (such as ethanol) in the liquid, a distillation column separates and purifies them using the differences in the boiling points of the components. The mixed solution is vaporized by heating. As the vapor rises in the tower, it comes into countercurrent contact with the descending liquid. Through multiple partial vaporizations and partial condensations, the organic solvent is separated from water and other impurities. The recovered organic solvent can be reused in the production process, thereby improving the recovery rate of raw materials.

[0034] The technical solution disclosed in this utility model embodiment allows for precise temperature control in the cryo-crystallization reactor, promoting the crystallization of 3-hydroxy-4-methoxycinnamonaldehyde from the reaction mixture. Subsequently, a centrifuge uses centrifugal force to completely separate the mother liquor from the 3-hydroxy-4-methoxycinnamonaldehyde crystals, minimizing mother liquor residue and significantly improving the purity of the 3-hydroxy-4-methoxycinnamonaldehyde crystals, resulting in high-quality 3-hydroxy-4-methoxycinnamonaldehyde. A mother liquor collection tank collects the mother liquor separated by the centrifuge and then transfers it to a distillation recovery reactor. The distillation recovery reactor performs vacuum distillation on the mother liquor, and the solvents and other components are condensed and stored in the mother liquor distillation collection tank, reducing waste discharge, environmental pollution, and the load and cost of wastewater treatment. The distillation residue is returned to the cryo-crystallization reactor for further cryo-crystallization and centrifugation to extract any remaining 3-hydroxy-4-methoxycinnamonaldehyde crystals, increasing the yield of the 3-hydroxy-4-methoxycinnamonaldehyde product, avoiding raw material waste, and reducing production costs.

[0035] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0036] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. A system for preparing 3-hydroxy-4-methoxycinnamaldehyde based on mother liquor, characterized by, The system for preparing 3-hydroxy-4-methoxycinnamic aldehyde based on mother liquor includes: a freeze crystallization vessel, a centrifuge, a mother liquor collection tank, a water recovery vessel, a condenser, and a mother liquor water collection tank. The outlet of the freeze crystallizer is connected to the inlet of the centrifuge. The freeze crystallizer freeze crystallizes the reaction mixture containing 3-hydroxy-4-methoxycinnamicaldehyde and then places it into the centrifuge for centrifugation to obtain mother liquor and 3-hydroxy-4-methoxycinnamicaldehyde crystals. The inlet of the mother liquor collection tank is connected to the outlet of the centrifuge, and the outlet of the mother liquor collection tank is connected to the inlet of the water distillation recovery kettle, so as to collect the mother liquor and then pass it into the water distillation recovery kettle for vacuum distillation. The first outlet of the water distillation recovery vessel is connected to the inlet of the condenser, and the outlet of the condenser is connected to the inlet of the mother liquor distillation collection tank, so that the effluent from the water distillation recovery vessel after distillation is condensed by the condenser and sent to the mother liquor distillation collection tank. The second outlet of the water distillation recovery vessel is connected to the inlet of the freeze crystallization vessel so that the residual liquid after distillation in the water distillation recovery vessel is transferred to the freeze crystallization vessel for freeze crystallization again, and then transferred to a centrifuge for centrifugation again to obtain 3-hydroxy-4-methoxycinnamicaldehyde crystals.

2. The system for preparing 3-hydroxy-4-methoxycinnamaldehyde based on mother liquor according to claim 1, characterized in that, The system also includes: a mother liquor pump; The mother liquor collection tank has a discharge port at the bottom, and the discharge port of the mother liquor collection tank is connected to the inlet of the mother liquor pump through a first pipe. The distillation water recovery vessel has a feed port at the top, and the outlet of the mother liquor pump is connected to the feed port of the distillation water recovery vessel through a second pipe. Both the first pipe and the second pipe are β-homopolymer polypropylene pipes.

3. The system for preparing 3-hydroxy-4-methoxycinnamaldehyde based on mother liquor according to claim 1, characterized in that, The discharge port of the freeze crystallizer is located at the bottom of the freeze crystallizer, the inlet of the centrifuge is located at the top of the centrifuge, and the centrifuge is located below the freeze crystallizer. The discharge port of the freeze crystallizer and the inlet of the centrifuge are connected by a third pipe, which is a β-homopolymer polypropylene pipe.

4. The system for preparing 3-hydroxy-4-methoxycinnamaldehyde based on mother liquor according to claim 1, characterized in that, The inlet of the mother liquor collection tank is located at the top of the mother liquor collection tank, and the outlet of the centrifuge is located on one side of the bottom of the centrifuge. The inlet of the mother liquor collection tank and the outlet of the centrifuge are connected through a fourth pipe, and the mother liquor collection tank is located below the centrifuge. The fourth pipe is a β-homopolymer polypropylene pipe.

5. The system for preparing 3-hydroxy-4-methoxycinnamaldehyde based on mother liquor according to claim 1, characterized in that, The first discharge port of the steam water recovery vessel is located at the top of the steam water recovery vessel, the inlet of the condenser is located at the top of the condenser, the first discharge port of the steam water recovery vessel is connected to the inlet through a fifth pipe, and the condenser is located above the steam water recovery vessel. The fifth pipe is a steel-lined PTFE pipe.

6. The system for preparing 3-hydroxy-4-methoxycinnamic aldehyde based on mother liquor according to claim 1, characterized in that, The discharge port of the condenser is located at the bottom of the condenser, and the inlet of the mother liquor distillation collection tank is located at the top of the mother liquor distillation collection tank. The discharge port of the condenser and the inlet of the mother liquor distillation collection tank are connected through a sixth pipe, and the condenser is located above the mother liquor distillation collection tank.

7. The system for preparing 3-hydroxy-4-methoxycinnamaldehyde based on mother liquor according to claim 1, characterized in that, The second outlet of the water recovery vessel is located at the bottom of the water recovery vessel, and the inlet of the freeze crystallization vessel is located at the top of the freeze crystallization vessel. The second outlet of the water recovery vessel and the inlet of the freeze crystallization vessel are connected by a seventh pipe, which is a β-homopolymer polypropylene pipe.

8. The system for preparing 3-hydroxy-4-methoxycinnamaldehyde based on mother liquor according to claim 1, characterized in that, The outlet of the mother liquor distillation collection tank is located below the mother liquor distillation collection tank. The outlet of the mother liquor distillation collection tank is connected to the environmental protection treatment equipment through the eighth pipe so that the liquid in the mother liquor distillation collection tank can be treated by the environmental protection treatment equipment.

9. The system for preparing 3-hydroxy-4-methoxycinnamaldehyde based on mother liquor according to claim 1, characterized in that, The temperature in the water recovery vessel is between 65°C and 75°C.

10. The system for preparing 3-hydroxy-4-methoxycinnamaldehyde based on mother liquor according to claim 1, characterized in that, The temperature in the freeze crystallization vessel is below 10°C.

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