A production process for trimethylolpropane tri(meth)acrylate

Abstract

This invention relates to the field of chemical technology, specifically to a production process for trimethylolpropane tri(meth)acrylate. The process includes a washing tank with an inner liner fixed inside, and a heating jacket covering the outside of the liner. The inner liner houses a washing pipe, a rotating rod, and a scraper. A connecting pipe is installed on the right side of the washing tank. The process also includes the following steps: S1, feeding raw materials; S2, heating and reflux; S3, sampling and testing; S4, washing and purification; S5, negative pressure concentration; S6, filtration and impurity removal; and S7, finished product storage. This invention uses a light component byproduct to esterify with acrylic acid, achieving resource recovery and utilization of the byproduct, thus reducing raw material costs. The process is simple, with mild reaction conditions, requiring no special equipment, further reducing production costs. It replaces traditional strong acid catalysts, reducing side reactions and wastewater discharge. The process is environmentally friendly and efficient; the product has excellent performance, and it facilitates auxiliary distribution of washing and wastewater discharge and collection of the finished product.

Description

[0001] This invention relates to the field of chemical technology, specifically to a production process for trimethylolpropane tri(meth)acrylate. Background Technology

[0002] Trimethylolpropane tri(meth)acrylate (TMPTA) is an important multifunctional acrylate monomer with excellent properties such as high double bond content, fast curing speed, low viscosity, high boiling point, and low volatility. It is widely used as an active crosslinking diluent in radiation curing and can also be used as a comonomer to synthesize special acrylic resins. Furthermore, it can be used as a crosslinking agent for rubber and plastics. Its emulsion copolymers, due to their good transparency, impact resistance, toughness, colorfastness, UV stability, and chemical stability, are also used as major dye adhesives in various coating preparations, synthetic fiber wadding, and non-textile bonding. However, the industrial synthesis of TMPTA mostly employs a direct esterification reaction process. This process typically uses strong organic or inorganic acids as catalysts, offering advantages such as smooth reaction, fast rate, and mature technology. However, it also has significant drawbacks: the strong acid catalyst is difficult to completely remove, leading not only to the discharge of large amounts of industrial wastewater and environmental pollution, but also to triggering various side reactions and generating unnecessary byproducts, affecting product purity and yield. Furthermore, in the production of trimethylolpropane (TMP) in the workshop, light component byproducts are inevitably generated. Currently, these byproducts are mostly sold at low prices, resulting in extremely low added value and failing to achieve efficient resource utilization. Therefore, in order to solve the above problems, a production process for trimethylolpropane tri(meth)acrylate is proposed. Summary of the Invention

[0003] The purpose of this invention is to provide a production process for trimethylolpropane tri(meth)acrylate to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a production process for trimethylolpropane tri(meth)acrylate, comprising a washing tank, and further comprising the following steps: S1. Raw Material Addition: Add the trimethylolpropane light component byproduct, acrylic acid, azeotropic agent, composite polymerization inhibitor, and catalyst sequentially to a container and stir until homogeneous. The trimethylolpropane light component byproduct is a light component byproduct generated during the TMP production process in the workshop. Its main components are trimethylolpropane and small amounts of low-carbon alcohols and ester impurities. The azeotropic agent is one or a mixture of cyclohexane and toluene in any proportion. The composite polymerization inhibitor is a mixture of hydroquinone and p-hydroxyanisole. The catalyst is one or a mixture of p-toluenesulfonic acid and methanesulfonic acid. S2, Heating and Reflux: Heat to 90-95℃, and after the system begins to reflux, maintain this temperature for the reaction. S3. Sampling and testing: Detect the acidity of the reaction solution to determine the heat preservation and reaction endpoint; continuously collect the water generated during the reaction. When the output water volume is close to the theoretical output water volume, start sampling to detect the acidity of the reaction solution. Take samples every 1-2 hours. When the acidity of the reaction solution is detected to be <5%, it is determined to be the reaction endpoint and the heat preservation is stopped.

[0005] S4. Washing and Purification: The reaction products are introduced into a washing tank for stepwise washing; including the following steps: First, wash twice with distilled water at 60°C, let stand and separate the layers, then discard the aqueous phase; Secondly, wash twice with a dilute alkaline solution with a mass concentration of 5-8% at 40℃, and discard the alkaline phase after standing and separating into layers. Finally, wash again with distilled water at 60°C, let stand to separate the phases, discard the aqueous phase and collect the oil phase.

[0006] S5. Negative pressure concentration: The washed product phase is placed in a negative pressure environment for negative pressure desolventization and concentration. S6. Filtration and impurity removal: The concentrated liquid is filtered through a precision filter to remove a small amount of mechanical impurities; S7. Finished Product Storage: Pour the filtered product into storage tanks for storage.

[0007] The washing tank is fixedly provided with an inner liner, and the outer side of the inner liner is wrapped with a heating sleeve. The inner liner is equipped with a washing pipe, a rotating rod and a scraper, and a connecting pipe is installed on the right side of the washing tank. As a further step of this solution, a coiled sleeve is filled between the inner liner and the heating sleeve, and the coiled sleeve is arranged to spiral around from bottom to top. An outer pad is fitted on the outside of the heating sleeve, and the space between the outer pad and the heating sleeve is hollow. The upper and lower ends of the inner liner, the heating sleeve and the outer pad are assembled and fastened by bolts and washers. The upper and lower parts of the heating sleeve and the outer pad are respectively fixed with a lower liquid pipe and an upper liquid pipe that communicate with the heating sleeve and the inner liner. Using the above-mentioned technical means, during use, the outer gasket, heating jacket, and inner liner are nested from the outside in, so as to realize the jacket heating to assist the heating of the material inside the inner liner. At the same time, the outer gasket provides external protection, and the setting of the coiled sleeve makes the heating more convenient and uniform. During use, the mold temperature controller is connected to the lower liquid pipe and the upper liquid pipe for auxiliary heating.

[0008] As a further step of this solution, a central column is vertically mounted in the center of the inner liner, and a rotating rod is inserted into the center of the central column through a bearing. An upper cover and a lower support are respectively mounted on the top and bottom of the inner liner, and lifting lugs are fixed on both sides of the upper cover. The bottom of the central column is inserted into the center of the upper cover, and a base frame is supported at the bottom of the lower support. The bottom of the lower support is arc-shaped with the inside higher than the outside, and a drain trough is integrally set around the bottom of the lower support. The bottoms of the four sets of drain troughs are connected and equipped with a lower ring pipe, and a discharge pipe is fixedly connected to the bottom left side of the lower ring pipe. Through the above-mentioned technical means, the inner liner, the middle column, the upper cover and the lower support are stacked and assembled to facilitate disassembly during subsequent cleaning. At the same time, with the cooperation of the drain trough, the lower ring pipe and the discharge pipe, it is also convenient to assist in the discharge of materials. The top of the upper cover has a connecting slot and through hole for assembling the necessary instruments and equipment, assisting in the introduction of products and monitoring the corresponding data. Meanwhile, the side of the base frame is equipped with a power distribution control cabinet.

[0009] As a further step of this solution, stirring rod one and stirring rod two are fixedly provided on both sides of the upper end of the rotating rod, and a motor is connected to the bottom of the rotating rod through a coupling. The motor is suspended on the inner bottom wall of the base frame. Stirring teeth are fixedly provided on the outer wall of stirring rod two. A side support corresponding to the scraper is sleeved on the outer wall of stirring rod one. The inner wall of the scraper is fixed to the outer end of the side support, and the outer wall of the side support is attached to the inner wall of the inner bushing.

[0010] Through the above-mentioned technical means, the rotating rod is driven by the motor to rotate, thereby driving the first and second stirring rods to rotate, making it easier to mix the internal materials evenly. At the same time, the scraper scrapes the inner wall of the inner liner, making it less likely to cause residue on the inner wall.

[0011] As a further step of this solution, the washing tube is arranged in a spiral shape from the inside to the outside, and the bottom of the washing tube is evenly provided with holes and grooves. The outer rear end of the washing tube is connected to and fixed with a connector, and the connector is inserted and assembled on the inner rear wall of the top cover.

[0012] Through the above-mentioned technical means, during the washing process, distilled water and alkaline solution are injected into the material through the corresponding pipes connected to the joint, and sprayed onto the material from above, making the subsequent mixing, washing and reaction more uniform, convenient and efficient.

[0013] As a further step of this solution, the right side wall of the inner liner is fixed with a connecting groove that communicates with the interior, and the left side of the connecting pipe is equipped with an installation head that mates with the connecting groove. The connecting groove and the installation head are evenly and equidistantly distributed from top to bottom. The outer wall of the connecting pipe is equipped with a viewing window, and a plug cap is threaded onto the top of the connecting pipe.

[0014] The above-mentioned technical means make it easier to observe the internal liquid position and the relative state and position of the upper and lower liquids after standing and stratification from the side, making subsequent operations such as draining, discarding, and collecting liquid more convenient and efficient.

[0015] As a further step of this solution, the inner liner is symmetrically equipped with an upper sampling tube and a lower sampling tube that are connected, and the upper sampling tube and the lower sampling tube are inserted through the outer wall of the heating sleeve and the outer pad sleeve.

[0016] The above-mentioned technical means facilitate sampling and testing during assembly and use, and allow for the installation of corresponding valves and other controls at the external end during assembly.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. By using low-value-added light component byproducts from the TMP production process as raw materials to replace part of pure trimethylolpropane, the added value of the byproducts is significantly increased, the downstream product chain of TMP is broadened, resource waste is reduced, and high-value utilization of byproducts is achieved; the introduction of low-cost byproducts into the raw materials reduces raw material costs; the process steps are simple, the reaction conditions are mild, no special equipment is required, and it is easy to achieve industrial-scale production, which also reduces production costs; 2. By using novel catalysts such as p-toluenesulfonic acid and methanesulfonic acid to replace traditional strong acid catalysts, side reactions are reduced and wastewater discharge is lowered. Stepwise washing and negative pressure concentration processes ensure product purity. The entire process is green and environmentally friendly, meeting industrial energy conservation and emission reduction requirements. The process is environmentally friendly and efficient. The obtained TMPTA product has an ester content of ≥80% and a cone-plate viscosity of 70-110 mPa·s. All performance indicators meet the requirements for use in radiation curing, resin synthesis, and other fields, demonstrating excellent product performance. 3. By setting up a washing tank, when washing the reacted materials, the washing pipe connects to the distilled water and alkali solution pipelines to inject and spray the materials inside the inner liner, which assists in washing the materials. During washing, the rotating rod and scraper drive the rotation to stir and scrape the side wall, so as to achieve more uniform washing and less residue. In addition, with the cooperation of the upper and lower sampling pipes, it is convenient to assist in sampling and detection, so as to determine the reaction endpoint. 4. In addition to the above structural design, the inner liner is heated by a mold temperature controller in conjunction with the heating jacket and the coiled jacket, so as to achieve constant temperature heating of the solution inside the inner liner, keep the subsequent washing and reaction more stable, and facilitate the observation and control of the liquid condition inside the washing tank with the help of the connecting pipe, so as to coordinate the subsequent liquid discharge. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the process flow of the present invention; Figure 2 This is a side-view perspective of the overall structure of the present invention; Figure 3 This is a bottom-view perspective view of the overall structure of the present invention; Figure 4 This is a three-dimensional sectional view of the structure of the present invention. Figure 5 This is a top-view cross-sectional perspective of the structure of the present invention; Figure 6 This is a side perspective three-dimensional schematic diagram of a partial structure of the rotating rod and scraper of the present invention; Figure 7 This is a three-dimensional front view cross-sectional diagram of a partial structure of the heating sleeve of the present invention; Figure 8 This is an exploded view of the three-dimensional assembly of the structure of the present invention.

[0020] In the diagram: 100, Washing tank; 101, Base frame; 110, Inner liner; 111, Central column; 112, Top cover; 113, Lower support chamber; 114, Drainage trough; 115, Lower ring pipe; 116, Discharge pipe; 117, Lifting lug; 120, Heating jacket; 121, Coiling sleeve; 122, Outer gasket; 123, Lower liquid pipe; 124, Upper liquid pipe; 130, Washing pipe; 131, Connecting joint; 140, Rotating rod; 141, Stirring rod one; 142, Stirring rod two; 143, Motor; 144, Stirring teeth; 150, Scraper; 151, Side support; 160, Connecting pipe; 161, Viewing window; 162, Connecting groove; 163, Mounting head; 164, Plug cap; 170, Upper sampling pipe; 171, Lower sampling pipe. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Please see Figures 1-8 The present invention provides an embodiment of a process for producing trimethylolpropane tri(meth)acrylate, comprising a washing tank 100, and further comprising the following steps: S1. Raw Material Addition: Add the following ingredients sequentially to a four-necked flask equipped with a thermometer, stirrer, distillation column, water separator, and condenser: trimethylolpropane light component by-product, acrylic acid, azeotropic agent, composite polymerization inhibitor, and catalyst. Stir until homogeneous. The mass ratio of trimethylolpropane light component by-product to acrylic acid is 63.1-126.2:953.6. The azeotropic agent accounts for 25.5-26.5% of the total mass of the reaction system, the composite polymerization inhibitor accounts for 0.1-0.5%, and the catalyst accounts for 0.5-1.5%. The trimethylolpropane light component by-product is a light component by-product generated during the TMP production process in the workshop. Its main components are trimethylolpropane and small amounts of low-carbon alcohols and ester impurities. The azeotropic agent is a mixture of one or two of cyclohexane and toluene in any proportion. The composite polymerization inhibitor is a mixture of hydroquinone and p-hydroxyanisole. The catalyst is a mixture of one or two of p-toluenesulfonic acid and methanesulfonic acid. S2. Heating and reflux: Heat to 90-95℃, and after the system begins to reflux, maintain this temperature for the reaction. S3. Sampling and testing: Detect the acidity of the reaction solution to determine the heat preservation and reaction endpoint; continuously collect the water generated during the reaction. When the output water volume is close to the theoretical output water volume, start sampling to detect the acidity of the reaction solution. Take samples every 1-2 hours. When the acidity of the reaction solution is detected to be <5%, it is determined to be the reaction endpoint and the heat preservation is stopped.

[0023] S4. Washing and purification: The reaction products are introduced into the washing tank 100 for stepwise washing; including the following steps: First, wash twice with distilled water at 60°C, each wash lasting 30 minutes. After standing and separating into layers, discard the aqueous phase. Secondly, wash twice with a dilute alkaline solution with a mass concentration of 5-8% at 40℃, each wash lasting 30 minutes. After standing and separating into layers, discard the alkaline phase. Finally, wash again with distilled water at 60°C, let stand to separate the phases, discard the aqueous phase and collect the oil phase.

[0024] S5. Negative pressure concentration: Place the washed product phase in a negative pressure environment and control the temperature at 50-60℃ to carry out negative pressure desolventization and concentration until the product content reaches 30-40%. S6. Filtration and impurity removal: The concentrated liquid is filtered through a precision filter to remove a small amount of mechanical impurities, and trimethylolpropane tri(meth)acrylate is obtained as the finished product. S7. Finished Product Storage: Pour the filtered product into storage tanks for storage.

[0025] The washing tank 100 is fixedly provided with an inner liner 110, and the heating jacket 120 is wrapped around the outside of the inner liner 110. The inner liner 110 is equipped with a washing pipe 130, a rotating rod 140 and a scraper 150. A connecting pipe 160 is installed on the right side of the washing tank 100. In a more detailed embodiment, a central column 111 is vertically mounted in the center of the inner sleeve 110. A rotating rod 140 is inserted into the center of the central column 111 via a bearing, providing support for the rotating rod 140 and ensuring more stable subsequent rotational transmission. An upper cover 112 and a lower support compartment 113 are respectively mounted on the top and bottom of the inner sleeve 110. Lifting lugs 117 are fixed on both sides of the upper cover 112 for auxiliary lifting when opening it. The bottom of the central column 111 is inserted into the center of the upper cover 112, allowing for the combined assembly of the upper cover 112 and the central column 111, secured with bolts. Sealing gaskets are used during assembly, facilitating subsequent disassembly. A base frame 101 supports the bottom of the lower support compartment 113. This design achieves overall support for the washing tank 100, making subsequent drainage more convenient. The bottom of the lower support compartment 113 is arc-shaped with an inner higher and outer lower design. Drainage channels 114 are integrally set around the bottom of the lower support compartment 113 to guide the flow of liquid to both sides and cooperate with the drainage channels 114 for drainage, making it less likely to cause residue. The bottom of the four sets of drainage channels 114 are connected and equipped with a lower ring pipe 115. A discharge pipe 116 is fixedly connected to the bottom left side of the lower ring pipe 115. During assembly, corresponding solenoid valves are installed between the four sets of drainage channels 114 and the lower ring pipe 115 to control the flow of liquid. The discharge pipe 116 is connected to the corresponding pipe for centralized drainage. With the cooperation of the four sets of drainage channels 114, the internal liquid flows out evenly and slowly during static drainage.

[0026] As described in more detail in this embodiment, a coiled sleeve 121 is filled and assembled between the inner liner 110 and the heating sleeve 120. The coiled sleeve 121 is arranged to spiral upwards to heat the inner liner 110, thereby ensuring that the liquid inside the inner liner 110 is heated at a uniform and constant temperature. An outer gasket 122 is fitted outside the heating sleeve 120. The space between the outer gasket 122 and the heating sleeve 120 is hollow, which provides insulation for the outside of the heating sleeve 120 and avoids heat damage during washing. The upper and lower ends of the inner liner 110, the heating sleeve 120, and the outer gasket 122 are fastened together with bolts and washers to facilitate disassembly and assembly. The upper and lower parts of the heating sleeve 120 and the outer gasket 122 are respectively fixed with a lower liquid pipe 123 and an upper liquid pipe 124 that communicate with the heating sleeve 120 and the inner liner 110, which facilitates the supply of a uniform and constant temperature heating medium by connecting to a mold temperature controller, so that the liquid inside the inner liner 110 is heated evenly and the solution maintains a stable temperature during washing.

[0027] As described in more detail in this embodiment, the washing tube 130 is arranged in a spiral shape from the inside to the outside. The bottom of the washing tube 130 is evenly provided with holes and grooves. The outer rear end of the washing tube 130 is connected to and fixed with a connector 131. The connector 131 is inserted and assembled on the inner rear wall of the top cover 112. During the washing process, the outer end of the connector 131 connects with the corresponding distilled water pipe and alkali pipe to ensure that the washing liquid is evenly introduced during the washing process.

[0028] As described in more detail in this embodiment, stirring rod 141 and stirring rod 142 are respectively fixed on both sides of the upper end of the rotating rod 140. The bottom of the rotating rod 140 is connected to a motor 143 through a coupling. The motor 143 is suspended from the inner bottom wall of the base frame 101, so that the rotating rod 140 is driven to rotate by the motor 143, thereby driving the stirring rod 141 and stirring rod 142 to rotate cyclically. This allows for the stirring of the material inside the inner liner 110 during washing, making washing more convenient and efficient. The outer wall of stirring rod 142 is fixed with a stirring rod. The teeth 144 assist in stirring, making the stirring more uniform and facilitating thorough and even mixing during washing. The outer wall of the stirring rod 141 is fitted with a side support 151 corresponding to the scraper 150. The inner wall of the scraper 150 is fixed to the outer end of the side support 151. The outer wall of the side support 151 is attached to the inner wall of the inner liner 110. When the stirring rod 141 makes a circular motion inside the inner liner 110, it simultaneously drives the scraper 150 to scrape the inner wall of the inner liner 110, avoiding long-term adhesion to the inner wall and facilitating subsequent scraping and cleaning of the inner wall.

[0029] As described in more detail in this embodiment, the right side wall of the inner liner 110 is fixed with a communicating groove 162 that communicates with the interior. The left side of the communicating pipe 160 is equipped with an installation head 163 that mates with the communicating groove 162. The communicating groove 162 and the installation head 163 are evenly distributed from top to bottom. The outer wall of the communicating pipe 160 is equipped with a viewing window 161. The top of the communicating pipe 160 is threaded with a plug cap 164. Utilizing the principle of communicating vessels, it is convenient to observe the liquid inside the inner liner 110 with the viewing window 161 open, making subsequent operations more convenient.

[0030] As described in more detail in this embodiment, the inner liner 110 is symmetrically equipped with an upper sampling tube 170 and a lower sampling tube 171 on the front side. The upper sampling tube 170 and the lower sampling tube 171 are inserted through the outer wall of the heating sleeve 120 and the outer pad sleeve 122 to facilitate auxiliary sampling and testing during washing, ensuring relatively thorough washing. That is, as needed, the upper and lower separated liquids can be sampled and tested after washing and settling to ensure the effect of settling. Example 1:

[0031] S1. Add raw materials: Add 126.20g of trimethylolpropane light component by-product, 542.72g of trimethylolpropane, 953.60g of acrylic acid, 450.0g of toluene (accounting for 26.0% of the total mass of the reaction system), 3.5g of composite polymerization inhibitor (accounting for 0.3% of the total mass of the reaction system), and 12.0g of p-toluenesulfonic acid (accounting for 1.0% of the total mass of the reaction system) to a 3L four-necked flask in sequence, and stir until homogeneous.

[0032] S2. Heating and reflux: Start stirring and heat the system to 90°C. After the system refluxes, maintain the temperature at 90°C for the reaction.

[0033] S3. Sampling and testing: Collect the water generated during the reaction. When the output water volume is close to the theoretical value, start sampling and testing. Take a sample every 1.5 hours. After 14 hours of reaction, the acidity of the reaction solution (calculated by AA) is measured to be 3.79%, which means the reaction has reached the endpoint. Stop the heat preservation.

[0034] S4. Washing and purification: Wash the reaction product twice with distilled water at 60°C for 30 minutes each time, and discard the aqueous phase; then wash twice with 6% sodium carbonate solution at 40°C for 30 minutes each time, and discard the alkaline phase; finally wash once with distilled water at 60°C, let it stand to separate into layers, and collect the oil phase.

[0035] S5. Negative pressure concentration: The oil phase is placed in a negative pressure environment (vacuum degree -0.09MPa) and the temperature is controlled at 58℃ to carry out negative pressure desolventization and concentration until the product content reaches 35.0%.

[0036] S6. Filtration and Impurity Removal: The concentrate is filtered through a 0.45μm precision filter to obtain the TMPTA product. Testing revealed that the ester content of the product was 81.7%, and the cone-plate viscosity was 78 mPa·s.

[0037] S7. Finished product storage: Fill and store in appropriate containers. Example 2:

[0038] S1. Add raw materials: Add 63.10g of trimethylolpropane light component by-product, 569.54g of trimethylolpropane, 953.60g of acrylic acid, 455.0g of toluene (accounting for 26.2% of the total mass of the reaction system), 3.2g of composite polymerization inhibitor (accounting for 0.28% of the total mass of the reaction system), and 11.5g of p-toluenesulfonic acid (accounting for 0.98% of the total mass of the reaction system) to a 3L four-necked flask in sequence, and stir until homogeneous.

[0039] S2. Heating and reflux: Start stirring and heat the system to 90°C. After the system refluxes, maintain the temperature at 90°C for the reaction.

[0040] S3. Sampling and testing: Collect the water generated during the reaction. When the output water volume is close to the theoretical value, start sampling and testing. Take a sample every hour. After 14 hours of reaction, the acidity of the reaction solution (calculated by AA) is measured to be 3.75%, which means the reaction has reached the endpoint. Stop the heat preservation.

[0041] S4. Washing and purification: Wash the reaction product twice with distilled water at 60°C for 30 minutes each time, and discard the aqueous phase; then wash twice with 6% sodium carbonate solution at 40°C for 30 minutes each time, and discard the alkaline liquid phase; finally wash once with distilled water at 60°C, let it stand to separate into layers, and collect the oil phase.

[0042] S5. Negative pressure concentration: The oil phase is placed in a negative pressure environment (vacuum degree -0.09MPa) and the temperature is controlled at 58℃ to carry out negative pressure desolventization and concentration until the product content reaches 35.8%.

[0043] S6. Filtration and Impurity Removal: The concentrate is filtered through a 0.45μm precision filter to obtain the TMPTA product. Testing revealed that the ester content of the product was 84.6%, and the cone-plate viscosity was 82 mPa·s.

[0044] S7. Finished product storage: Fill and store in appropriate containers.

[0045] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Those skilled in the art can readily implement the present invention based on the accompanying drawings and the above description. However, any modifications, alterations, or variations made by those skilled in the art without departing from the scope of the present invention, utilizing the disclosed technical content, are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, or variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.

Claims

1. A process for producing trimethylolpropane tri(meth)acrylate, comprising a washing tank, characterized in that: The washing tank is fixedly provided with an inner liner, and the outer side of the inner liner is wrapped with a heating sleeve. The inner liner is equipped with a washing pipe, a rotating rod and a scraper, and a connecting pipe is installed on the right side of the washing tank. It also includes the following steps: S1. Add raw materials: Add trimethylolpropane light component by-product, acrylic acid, azeotropic agent, composite polymerization inhibitor and catalyst in sequence to the container, and stir evenly; S2. Heating and reflux: Heat to 90-95℃, and after the system begins to reflux, maintain this temperature for the reaction. S3. Sampling and testing: Detect the acidity of the reaction solution to determine the temperature holding time and the reaction endpoint; S4. Washing and purification: The reaction products are introduced into the washing tank for stepwise washing. S5. Negative pressure concentration: The washed product phase is placed in a negative pressure environment for negative pressure desolventization and concentration. S6. Filtration and impurity removal: The concentrated liquid is filtered through a precision filter to remove a small amount of mechanical impurities; S7. Finished Product Storage: Pour the filtered product into storage tanks for storage.

2. The production process of trimethylolpropane tri(meth)acrylate according to claim 1, characterized in that: The trimethylolpropane light component byproduct in S1 is a light component byproduct generated during the TMP production process in the workshop. Its main components are trimethylolpropane and a small amount of low-carbon alcohols and ester impurities. The azeotropic agent in S1 is one or a mixture of two of cyclohexane and toluene in any proportion; The composite polymerization inhibitor in S1 is a mixture of hydroquinone and p-hydroxyanisole. The catalyst in S1 is one or a mixture of two of p-toluenesulfonic acid and methanesulfonic acid.

3. The production process of trimethylolpropane tri(meth)acrylate according to claim 1, characterized in that: The heat preservation and reaction endpoint determination in S3 include the following operations: continuously collect the water generated during the reaction; when the water output is close to the theoretical output, start sampling to detect the acidity of the reaction solution; take samples every 1-2 hours; when the acidity of the reaction solution is detected to be <5%, it is determined to be the reaction endpoint and the heat preservation is stopped.

4. The production process of trimethylolpropane tri(meth)acrylate according to claim 1, characterized in that: The step-by-step washing in S4 includes the following steps in sequence: First, wash twice with distilled water at 60°C, let stand and separate the layers, then discard the aqueous phase; Secondly, wash twice with a dilute alkaline solution with a mass concentration of 5-8% at 40℃, and discard the alkaline phase after standing and separating into layers. Finally, wash again with distilled water at 60°C, let stand to separate the phases, discard the aqueous phase and collect the oil phase.

5. The production process of trimethylolpropane tri(meth)acrylate according to claim 1, characterized in that: A coiled sleeve is filled between the inner liner and the heating sleeve, and the coiled sleeve is arranged to spiral upwards. An outer pad is fitted outside the heating sleeve, and the space between the outer pad and the heating sleeve is hollow. The upper and lower ends of the inner liner, heating sleeve and outer pad are assembled and fastened by bolts and washers. The upper and lower parts of the heating sleeve and the outer pad are respectively fixed with a lower liquid pipe and an upper liquid pipe that communicate with the heating sleeve and the inner liner.

6. The production process of trimethylolpropane tri(meth)acrylate according to claim 1, characterized in that: A central column is vertically mounted in the center of the inner liner, and a rotating rod is inserted into the center of the central column via a bearing. An upper cover and a lower support are respectively mounted on the top and bottom of the inner liner, and lifting lugs are fixed on both sides of the upper cover. The bottom of the central column is inserted into the center of the upper cover, and a base frame supports the bottom of the lower support. The bottom of the lower support is arc-shaped with the inside higher than the outside, and a drain trough is integrally set around the bottom of the lower support. The bottoms of the four sets of drain troughs are connected and equipped with a lower ring pipe, and a discharge pipe is fixedly connected to the bottom left side of the lower ring pipe.

7. The production process of trimethylolpropane tri(meth)acrylate according to claim 6, characterized in that: The upper end of the rotating rod is fixed with stirring rod one and stirring rod two respectively, and the bottom of the rotating rod is connected to a motor through a coupling. The motor is suspended on the inner bottom wall of the base frame. The outer wall of stirring rod two is fixed with stirring teeth. The outer wall of stirring rod one is fitted with a side support corresponding to the scraper. The inner wall of the scraper is fixed to the outer end of the side support, and the outer wall of the side support is attached to the inner wall of the inner bushing.

8. The production process of trimethylolpropane tri(meth)acrylate according to claim 6, characterized in that: The washing tube is arranged in a spiral shape from the inside to the outside, and the bottom of the washing tube is evenly provided with holes and grooves. The outer rear end of the washing tube is connected to and fixed with a connector, which is inserted and assembled into the inner rear wall of the top cover.

9. The production process of trimethylolpropane tri(meth)acrylate according to claim 5, characterized in that: The inner liner is fixed with a connecting groove on the right side wall, and the connecting pipe is equipped with an installation head that mates with the connecting groove on the left side. The connecting groove and the installation head are evenly distributed from top to bottom. The connecting pipe is equipped with a viewing window on the outer wall, and a plug is threaded onto the top of the connecting pipe.

10. The production process of trimethylolpropane tri(meth)acrylate according to claim 5, characterized in that: The inner liner is symmetrically fitted with an upper sampling tube and a lower sampling tube that are connected to each other on the front side, and the upper sampling tube and the lower sampling tube are inserted through the outer wall of the heating sleeve and the outer pad sleeve.

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