A process and system for continuous preparation of ruby ​​esterification liquid

Abstract

This invention discloses a process and system for the continuous preparation of ruby ​​esterification liquid. Water and m-aminoacetanilide are mixed at a mass ratio of 1:10-12 and heated to dissolve, yielding a m-aminoacetanilide solution. First, 3%-10% of the total mass of the m-aminoacetanilide solution is pumped into a receiving vessel via a hydroxylation tubular mixer. Then, the remaining m-aminoacetanilide solution and ethylene oxide are simultaneously and continuously pumped into the receiving vessel via the hydroxylation tubular mixer at a m-aminoacetanilide:ethylene oxide molar ratio of 1:1.7-1.9. The receiving vessel continuously discharges into a hydroxylation transfer vessel. Ethylene oxide is added to the hydroxylation transfer vessel at a continuously fed receiving vessel m-aminoacetanilide:ethylene oxide molar ratio of 1:0.3-0.5. The discharge from the hydroxylation transfer vessel, along with acetic anhydride, continuously enters the esterification unit. The molar ratio of 3-(N,N-dihydroxyethyl)aminoacetanilide in the acetic anhydride and the hydroxylation transfer vessel discharge is not less than 1.2:1. The esterification unit continuously discharges into a deacidification vessel, where acetic acid is recovered and then cooled to obtain the finished red jade esterified solution.

Description

Technical Field

[0001] This invention relates to the field of dye production technology, specifically to a process and system for the continuous preparation of ruby ​​esterification liquid. Background Technology

[0002] Disperse red series dyes occupy an important position among dye varieties, especially CI Disperse Red Ruby. Because of its wide application in dyeing polyester fibers, it has a wide acceptance in the dye market. Therefore, the synthesis of its intermediate 3-acetamido-N,N-diacetoxyethylaniline is crucial.

[0003] Red jade esterification solutions are typically prepared by a one-step esterification reaction of the corresponding hydroxylated compound 3-(N,N-dihydroxyethyl)aminoacetanilide with a carboxylic acid or anhydride. Anhydrides are highly reactive and can be used for the esterification of less reactive or sterically hindered alcohol hydroxyl groups. In traditional industrial production, acetic anhydride is commonly used as the esterifying agent in the production of esterification solutions.

[0004] The current method for synthesizing ruby ​​esterified liquid involves adding a measured amount of 3-(N,N-dihydroxyethyl)aminoacetanilide and acetic acid to a reaction apparatus in a molar ratio of 1:2.6–2.8. The mixture is then heated to 80–85°C and held at that temperature for two hours. After cooling, samples are taken for testing. The ruby ​​esterified liquid produced by this process has a 3-(N,N-diacetoxyethyl)aminoacetanilide purity of only 88%–90%.

[0005] Patent specification CN104710322A discloses a method for synthesizing a ruby ​​esterification solution. The method uses 3-(NN-dihydroxyethyl)aminoacetanilide and acetic anhydride as raw materials. The acetic anhydride is added in two stages. After the first addition of a portion of the acetic anhydride, the reaction is carried out at 50–55°C for 4–6 hours. Then, the remaining acetic anhydride is added, and the reaction is carried out at 45–50°C for 8–10 hours. Finally, acetic acid is added to the reaction solution for dilution, and the mixture is cooled to obtain the ruby ​​esterification solution. The ruby ​​esterification solution obtained by this patented technology has a purity of over 94% for the main component, 3-(NN-diacetoxyethyl)aminoacetanilide, a shelf life of up to 6 months, and a super-ester content of ≤2%.

[0006] Patent specification CN113444012A discloses a method for preparing a ruby ​​esterification solution, comprising the following steps: using 3-(NN-dihydroxyethyl)aminoacetanilide and excess acetic acid as raw materials, the acetic acid is added at least twice and reacted with 3-(NN-dihydroxyethyl)aminoacetanilide; wherein, after each addition of acetic acid, a portion of the acetic acid reaction solution is separated during the reaction with 3-(NN-dihydroxyethyl)aminoacetanilide. The ruby ​​esterification solution obtained by this patented technology has a purity of over 95%, an excess ester content of less than 1.5%, and a shelf life of over one year. Summary of the Invention

[0007] This invention provides a process and system for the continuous preparation of ruby ​​esterification liquid. By using a tubular mixer to enhance the mixing process of raw materials, the amount of water used in the reaction is reduced, the dehydration step of the hydroxylation reaction is eliminated, and the esterification raw material is acetic anhydride, eliminating the step of dediluted acetic acid in the reaction process. The feeding sequence and ratio are precisely controlled, which improves the reaction efficiency, shortens the system residence time, improves the utilization rate of raw materials, can improve the purity of 3-(N,N-diacetoxyethyl)aminoacetanilide, and the production process is continuous and the synthesis cost is reduced.

[0008] A process for the continuous preparation of ruby ​​esterification liquid includes:

[0009] Raw material pulping: Water and m-aminoacetanilide are mixed at a mass ratio of 1:10-12 and heated to dissolve, yielding a m-aminoacetanilide solution;

[0010] Feeding and Reaction: Before the reaction begins, 3% to 10% of the total mass of the m-aminoacetanilide solution is pumped into the receiving vessel via a hydroxylation tubular mixer. Then, the remaining m-aminoacetanilide solution and ethylene oxide are simultaneously and continuously pumped into the receiving vessel via the hydroxylation tubular mixer at a m-aminoacetanilide:ethylene oxide molar ratio of 1:1.7 to 1.9. The receiving vessel continuously discharges into the hydroxylation transfer vessel to continue the reaction. Ethylene oxide is added to the hydroxylation transfer vessel at a continuously fed m-aminoacetanilide:ethylene oxide molar ratio of 1:0.3 to 0.5. The discharge from the hydroxylation transfer vessel, together with acetic anhydride, continuously enters the esterification unit for reaction. The molar ratio of acetic anhydride to 3-(N,N-dihydroxyethyl)aminoacetanilide in the hydroxylation transfer vessel discharge is not less than 1.2:1 (preferably 1.2 to 1.5:1).

[0011] Post-processing: The esterification unit continuously discharges the product into the deacidification kettle, and after heating to recover acetic acid, it is cooled to obtain the finished red jade esterified liquid.

[0012] In one embodiment, water and m-aminoacetanilide are mixed at a mass ratio of 1:10 to 12 and heated to 80 to 90°C to dissolve.

[0013] In one embodiment, the temperature of the receiving vessel and the hydroxylation transfer vessel is controlled at 80–90°C.

[0014] In one embodiment, the material residence time in the receiving vessel is 1 to 2 hours.

[0015] In one embodiment, the residence time of the material in the hydroxylation transfer vessel is 5 to 8 hours.

[0016] In one embodiment, the total molar ratio of m-aminoacetanilide to ethylene oxide continuously fed into the receiving vessel is 1:2.1 to 2.2.

[0017] In one embodiment, the temperature of the esterification unit is controlled at 95–105°C.

[0018] In one embodiment, the residence time of the material in the esterification unit is 10–20 h.

[0019] In one embodiment, the esterification unit includes a first esterification vessel and a second esterification vessel connected sequentially along the process route.

[0020] In one embodiment, the residence time of the material in the first esterification reactor is 5 to 10 hours.

[0021] In one embodiment, the residence time of the material in the second esterification reactor is 5 to 10 hours.

[0022] In one embodiment, the hydroxylation transfer reactor output, along with acetic anhydride, is continuously fed into the esterification unit via an esterification tubular mixer.

[0023] In one embodiment, the temperature of the deacidification vessel is controlled at 130–140°C.

[0024] A system for the continuous preparation of ruby ​​esterification liquid includes a hydroxylation tubular mixer, a receiving vessel, a hydroxylation transfer vessel, an esterification unit, and a deacidification vessel connected in sequence.

[0025] The hydroxylation tubular mixer is connected to the m-aminoacetanilide pulping vessel and the ethylene oxide metering tank;

[0026] The hydroxylation transfer vessel is equipped with an ethylene oxide replenishment port;

[0027] The esterification unit is connected to the acetic anhydride metering tank.

[0028] In one embodiment, the hydroxylation transfer vessel is connected to the esterification unit via an esterification tubular mixer, and the esterification unit is connected to the acetic anhydride metering tank via the esterification tubular mixer.

[0029] The system for continuous preparation of ruby ​​esterification liquid can be used to perform the process for continuous preparation of ruby ​​esterification liquid.

[0030] Compared with the prior art, the beneficial effects of this invention are as follows:

[0031] 1) Introducing a tubular mixer enhances the mixing efficiency of raw materials, strengthens mass transfer, shortens reaction time, and reduces the consumption of ethylene oxide and acetic anhydride.

[0032] 2) Adjusting the feeding method, such as introducing a portion of the m-aminoacetanilide solution at the beginning of the reaction, can further improve product purity, shorten reaction time, and reduce reaction pressure.

[0033] 3) Ethylene oxide is added in two parts, and the amount of ethylene oxide added in each part is strictly controlled to reduce the amount of ethylene oxide used while improving the purity of the product.

[0034] 4) The reaction process is simple. Acetic anhydride can be used as a raw material for the reaction and can also consume the water in the reaction process, thus eliminating the dehydration step in the reaction process and further shortening the reaction time.

[0035] 5) It can be fully automated and interlocked to achieve continuous production and ensure product quality. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of a continuous process for preparing ruby ​​esterification liquid according to the present invention.

[0037] Figure 2 This is a schematic diagram of the system structure for the continuous preparation of ruby ​​esterification liquid according to the present invention. Detailed Implementation

[0038] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0039] Unless otherwise specified, the operating methods in the following examples are generally performed under conventional conditions or as recommended by the manufacturer.

[0040] See Figure 1 A process for the continuous preparation of ruby ​​esterification liquid includes:

[0041] Raw material pulping: Water and m-aminoacetanilide are mixed at a mass ratio of 1:10-12 and heated to 80-90℃ to dissolve, thus obtaining a m-aminoacetanilide solution;

[0042] Feeding and Reaction: Before the reaction begins, 3%–10% of the total mass of the m-aminoacetanilide solution is pumped into the receiving vessel via a hydroxylation tubular mixer. Then, the remaining m-aminoacetanilide solution and ethylene oxide are simultaneously and continuously pumped into the receiving vessel via the hydroxylation tubular mixer at a m-aminoacetanilide:ethylene oxide molar ratio of 1:1.7–1.9. The receiving vessel continuously discharges into a hydroxylation transfer vessel to continue the reaction. Ethylene oxide is replenished in the hydroxylation transfer vessel at a continuously fed m-aminoacetanilide:ethylene oxide molar ratio of 1:0.3–0.5, resulting in a total continuously fed m-aminoacetanilide to ethylene oxide molar ratio of 1:2.1–2.2. The temperatures of the receiving vessel and the hydroxylation transfer vessel are controlled at 80–90°C. The residence time of the material in the receiving vessel is 1–2 h, and the residence time of the material in the hydroxylation transfer vessel is 5–8 h. The effluent from the hydroxylation transfer vessel, together with acetic anhydride, is continuously fed into the first esterification vessel and the second esterification vessel sequentially via an esterification tubular mixer. The temperatures of the first and second esterification vessels are controlled at 95–105°C. The residence time of the material in the first esterification vessel is 5–10 h, and the residence time of the material in the second esterification vessel is 5–10 h. The molar ratio of acetic anhydride to 3-(N,N-dihydroxyethyl)aminoacetanilide in the effluent from the hydroxylation transfer vessel is not less than 1.2:1, preferably 1.2–1.5:1.

[0043] Post-processing: The second esterification reactor continuously discharges the material into the deacidification reactor, and after heating to 130-140℃ to recover acetic acid, it is cooled to obtain the finished red jade esterification liquid.

[0044] See Figure 2 A system for the continuous preparation of ruby ​​esterification liquid includes an acetic anhydride metering tank 1, a m-aminoacetanilide pulping tank 2, an ethylene oxide metering tank 3, and a hydroxylation tubular mixer 9, a receiving tank 4, a fourth metering pump 14, a hydroxylation transfer tank 5, a fifth metering pump 15, an esterification tubular mixer 10, a first esterification tank 6, a sixth metering pump 16, a second esterification tank 7, a seventh metering pump 17, and a deacidification tank 8, connected in sequence. The acetic anhydride metering tank 1 is connected to the esterification tubular mixer 10 via the first metering pump 11. The m-aminoacetanilide pulping tank 2 and the ethylene oxide metering tank 3 are connected to the hydroxylation tubular mixer 9 via the second metering pump 12 and the third metering pump 13, respectively. The hydroxylation transfer tank 5 is equipped with an ethylene oxide replenishment port. The ethylene oxide metering tank 3 is connected to the ethylene oxide replenishment port of the hydroxylation transfer tank 5 via the eighth metering pump 18.

[0045] The above are as follows Figure 2 The system shown can be used for the continuous preparation of ruby ​​esterification liquid to perform the above-mentioned procedures. Figure 1 The process shown is for the continuous preparation of ruby ​​esterification solution.

[0046] The dwell time in the following embodiments and comparative examples are all optimal values ​​under the corresponding conditions.

[0047] Example 1

[0048] Using the above-mentioned methods Figure 1 The process for continuous preparation of ruby ​​esterification liquid shown, and as follows Figure 2 The system shown is for the continuous preparation of ruby ​​esterification solution.

[0049] (1) Add water and m-aminoacetanilide in a mass ratio of 1:10 to the m-aminoacetanilide slurrying vessel, heat to 85°C to dissolve, and obtain m-aminoacetanilide solution.

[0050] (2) 5% of the total weight of the m-aminoacetanilide solution was pumped into the receiving vessel via a hydroxylation tubular mixer. The feed flow rate of the m-aminoacetanilide solution was 60 kg / h, and the feed flow rate of ethylene oxide was 28.7 kg / h. The solution was then continuously pumped into the receiving vessel via the hydroxylation tubular mixer and then into the hydroxylation transfer vessel via a metering pump. The ethylene oxide feed flow rate to the hydroxylation transfer vessel was 6.07 kg / h. The temperatures of the receiving vessel and the hydroxylation transfer vessel were controlled at 88°C. The hydroxylation transfer vessel was fed into the first esterification vessel simultaneously via an esterification tubular mixer at a flow rate of 95 kg / h and acetic anhydride at a flow rate of 50 kg / h. The solution was then discharged into the second esterification vessel. The temperatures of the first and second esterification vessels were controlled at 102°C. The total residence time was 22 h, of which 1.5 h was in the receiving vessel, 6 h in the hydroxylation transfer vessel, 7.5 h in the first esterification vessel, and 7 h in the second esterification vessel.

[0051] (3) The second esterification reactor continuously discharges the material to the deacidification reactor. The acetic acid is removed in the deacidification reactor at 130°C. The material is then discharged, and the acetic acid is recovered and reused. Finally, 1300 kg of Hongyu esterification liquid is obtained. The purity of the finished product is 97%, the superesterification is less than 1%, and the yield is 90%.

[0052] Comparative Example 1

[0053] Similar to Example 1, the main difference is that the proportion of water used for pulping is reduced.

[0054] (1) Add water and m-aminoacetanilide in a mass ratio of 1:13 to the m-aminoacetanilide slurrying vessel, heat to 85°C to dissolve, and obtain m-aminoacetanilide solution.

[0055] (2) 5% of the total weight of the m-aminoacetanilide solution was pumped into the receiving vessel via a hydroxylation tubular mixer. The feed flow rate of the m-aminoacetanilide solution was 58.4 kg / h, and the feed flow rate of ethylene oxide was 28.7 kg / h. The solution was continuously pumped into the receiving vessel via the hydroxylation tubular mixer and then pumped into the hydroxylation transfer vessel via a metering pump. The ethylene oxide feed flow rate to the hydroxylation transfer vessel was 6.07 kg / h. The temperature of the receiving vessel and the hydroxylation transfer vessel was controlled at 88°C. The hydroxylation transfer vessel was fed into the first esterification vessel simultaneously via an esterification tubular mixer at a flow rate of 93 kg / h and acetic anhydride at a flow rate of 50 kg / h. The solution was then discharged into the second esterification vessel. The temperature of the first and second esterification vessels was controlled at 102°C. The total residence time was 28.5 h, of which the receiving vessel was 1.5 h, the hydroxylation transfer vessel was 6 h, the first esterification vessel was 11 h, and the second esterification vessel was 10 h.

[0056] (3) The second esterification reactor continuously discharges the material to the deacidification reactor, where the acetic acid is removed at 130°C. The material is then discharged, and the acetic acid is recovered and reused. Finally, 1200 kg of Hongyu esterification liquid is obtained, with a product purity of 90% and a yield of 88%.

[0057] Comparative Example 2

[0058] Similar to Example 1, the main difference is that the molar ratio of ethylene oxide feed is changed twice, while the total molar ratio of ethylene oxide to m-aminoacetanilide remains unchanged.

[0059] (1) Add water and m-aminoacetanilide in a mass ratio of 1:10 to the m-aminoacetanilide slurrying vessel, heat to 85°C to dissolve, and obtain m-aminoacetanilide solution.

[0060] (2) 5% of the total weight of the m-aminoacetanilide solution was pumped into the receiving vessel via a hydroxylation tubular mixer. The feed flow rate of the m-aminoacetanilide solution was 60 kg / h, and the feed flow rate of ethylene oxide was 25.6 kg / h. The solution was then continuously pumped into the receiving vessel via the hydroxylation tubular mixer and then into the hydroxylation transfer vessel via a metering pump. The ethylene oxide feed flow rate to the hydroxylation transfer vessel was 9.3 kg / h. The temperature of the receiving vessel and the hydroxylation transfer vessel was controlled at 88°C. The hydroxylation transfer vessel was fed into the first esterification vessel simultaneously via an esterification tubular mixer at a flow rate of 95 kg / h and acetic anhydride at a flow rate of 50 kg / h. The solution was then discharged into the second esterification vessel. The temperature of the first and second esterification vessels was controlled at 102°C. The total residence time was 24 h, of which the receiving vessel was 1.5 h, the hydroxylation transfer vessel was 8 h, the first esterification vessel was 7.5 h, and the second esterification vessel was 7 h.

[0061] (3) The second esterification reactor continuously discharges the material to the deacidification reactor, where the acetic acid is removed at 130°C. The material is then discharged, and the acetic acid is recovered and reused. Finally, 1300 kg of Hongyu esterification liquid is obtained, with a product purity of 87% and a yield of 90%.

[0062] Comparative Example 3

[0063] Similar to Example 1, the main difference is that the proportion of acetic anhydride used is reduced.

[0064] (1) Add water and m-aminoacetanilide in a mass ratio of 1:10 to the m-aminoacetanilide slurrying vessel, heat to 85°C to dissolve, and obtain m-aminoacetanilide solution.

[0065] (2) 5% of the total weight of the m-aminoacetanilide solution was pumped into the receiving vessel via a hydroxylation tubular mixer. The feed flow rate of the m-aminoacetanilide solution was 60 kg / h, and the feed flow rate of ethylene oxide was 28.7 kg / h. The solution was then continuously pumped into the receiving vessel via the hydroxylation tubular mixer and then into the hydroxylation transfer vessel via a metering pump. The ethylene oxide feed flow rate to the hydroxylation transfer vessel was 6.07 kg / h. The temperature of the receiving vessel and the hydroxylation transfer vessel was controlled at 88°C. The hydroxylation transfer vessel was fed into the first esterification vessel simultaneously via an esterification tubular mixer at a flow rate of 95 kg / h and acetic anhydride at a flow rate of 42.37 kg / h. The solution was then discharged into the second esterification vessel. The temperature of the first and second esterification vessels was controlled at 102°C. The total residence time was 30 h, of which the receiving vessel was 1.5 h, the hydroxylation transfer vessel was 6 h, the first esterification vessel was 10.5 h, and the second esterification vessel was 12 h.

[0066] (3) The second esterification reactor continuously discharges the material to the deacidification reactor, where acetic acid is removed at 130°C. The material is then discharged, and the acetic acid is recovered and reused. Finally, 1100 kg of Hongyu esterification liquid is obtained, with a product purity of 85% and a yield of 85.3%.

[0067] Comparative Example 4

[0068] Similar to Example 1, the main difference is that no portion of the m-aminoacetanilide solution was pre-pumped into the receiving vessel.

[0069] (1) Add water and m-aminoacetanilide in a mass ratio of 1:10 to the m-aminoacetanilide slurrying vessel, heat to 85°C to dissolve, and obtain m-aminoacetanilide solution.

[0070] (2) The feed flow rate of m-aminoacetanilide solution is 60 kg / h, and the feed flow rate of ethylene oxide is 28.7 kg / h. The solution is continuously pumped into the receiving vessel through a hydroxylation tubular mixer and then pumped into the hydroxylation transfer vessel through a metering pump. The ethylene oxide replenishment flow rate in the hydroxylation transfer vessel is 6.07 kg / h. The temperature of the receiving vessel and the hydroxylation transfer vessel is controlled at 88℃. The hydroxylation transfer vessel is fed into the first esterification vessel at a flow rate of 95 kg / h and acetic anhydride at a flow rate of 50 kg / h through an esterification tubular mixer. The solution is then discharged into the second esterification vessel. The temperature of the first and second esterification vessels is controlled at 102℃. The total residence time is 24 h, of which the receiving vessel is 2.5 h, the hydroxylation transfer vessel is 7 h, the first esterification vessel is 7.5 h, and the second esterification vessel is 7 h.

[0071] (3) The second esterification reactor continuously discharges the material to the deacidification reactor, where the acetic acid is removed at 130°C. The material is then discharged, and the acetic acid is recovered and reused. Finally, 1300 kg of Hongyu esterification liquid is obtained, with a product purity of 92% and a yield of 90%.

[0072] Comparative Example 5

[0073] Similar to Example 1, the main difference is that a hydroxylation tubular mixer was not used.

[0074] (1) Add water and m-aminoacetanilide in a mass ratio of 1:10 to the m-aminoacetanilide slurrying vessel, heat to 85°C to dissolve, and obtain m-aminoacetanilide solution.

[0075] (2) After pumping 5% of the total weight of the m-aminoacetanilide solution into the receiving vessel, the feed flow rate of the m-aminoacetanilide solution is 60 kg / h, and the feed flow rate of ethylene oxide is 28.7 kg / h. After being fed into the receiving vessel, the solution is pumped into the hydroxylation transfer vessel by a metering pump. The ethylene oxide replenishment flow rate in the hydroxylation transfer vessel is 6.07 kg / h. The temperature of the receiving vessel and the hydroxylation transfer vessel is controlled at 88℃. The hydroxylation transfer vessel is fed into the first esterification vessel at a rate of 95 kg / h and acetic anhydride at a rate of 50 kg / h simultaneously through the esterification tubular mixer, and then discharged into the second esterification vessel. The temperature of the first esterification vessel and the second esterification vessel is controlled at 102℃. The total residence time is 33 h, of which the receiving vessel is 2.5 h, the hydroxylation transfer vessel is 10 h, the first esterification vessel is 9.5 h, and the second esterification vessel is 11 h.

[0076] (3) The second esterification reactor continuously discharges the material to the deacidification reactor, where the acetic acid is removed at 130°C. The material is then discharged, and the acetic acid is recovered and reused. Finally, 1290 kg of Hongyu esterification liquid is obtained, with a product purity of 94% and a yield of 89%.

[0077] Furthermore, it should be understood that after reading the above description of the present invention, those skilled in the art can make various alterations or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A process for the continuous preparation of ruby ​​esterification liquid, characterized in that, include: (1) Add water and m-aminoacetanilide in a mass ratio of 1:10 to the m-aminoacetanilide slurrying vessel, heat to 85°C to dissolve, and obtain m-aminoacetanilide solution; (2) After pumping 5% of the total weight of the m-aminoacetanilide solution into the receiving vessel via a hydroxylation tubular mixer, the feed flow rate of the m-aminoacetanilide solution is 60 kg / h, and the feed flow rate of ethylene oxide is 28.7 kg / h. The solution is continuously pumped into the receiving vessel via the hydroxylation tubular mixer and then pumped into the hydroxylation transfer vessel via a metering pump. The ethylene oxide replenishment flow rate in the hydroxylation transfer vessel is 6.07 kg / h. The temperature of the receiving vessel and the hydroxylation transfer vessel is controlled at 88℃. The hydroxylation transfer vessel is fed into the first esterification vessel at a rate of 95 kg / h and acetic anhydride at a rate of 50 kg / h via an esterification tubular mixer, and then discharged into the second esterification vessel. The temperature of the first esterification vessel and the second esterification vessel is controlled at 102℃. The total residence time is 22h, of which the receiving vessel is 1.5h, the hydroxylation transfer vessel is 6h, the first esterification vessel is 7.5h, and the second esterification vessel is 7h. (3) The second esterification reactor continuously discharges the material to the deacidification reactor. The acetic acid is removed in the deacidification reactor at 130°C. The material is then discharged, and the acetic acid is recovered and reused. Finally, 1300 kg of Hongyu esterification liquid is obtained. The purity of the finished product is 97%, the esterification rate is less than 1%, and the yield is 90%.

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