Preparation process of 4-hydroxybutyl vinyl ether

Abstract

The invention relates to the technical field of chemical engineering and processes, and particularly discloses a preparation process of 4-hydroxybutyl vinyl ether. The raw materials comprise porous carriers such as potassium hydroxide, 1, 4-butanediol, acetylene, modified aluminum oxide or molecular sieves, palladium-based and nickel-based hydrogenation catalysts and the like; the preparation method comprises the following steps: firstly, preparing an immobilized catalyst through mixed loading and activation, constructing an inert environment through nitrogen displacement, then carrying out reactive distillation, then carrying out multi-stage separation, secondary displacement, material purification circulation and by-product directional hydro-conversion to realize efficient reuse of raw materials, and strengthening product purification through an organic vapor permeable membrane. The product can be used in the fields of high-grade coatings, environment-friendly adhesives, high-end electronic chemicals and the like, and meets the requirements of high-added-value fine chemical intermediates; the preparation method has the outstanding advantages of continuous and stable process operation, high separation precision, excellent raw material utilization rate and product purity, and by-product recycling.

Description

Technical Field

[0001] This application relates to the field of chemical engineering and process technology, and more specifically, to a process for preparing 4-hydroxybutyl vinyl ether. Background Technology

[0002] 4-Hydroxybutylvinyl ether (HBE), an important fine chemical intermediate, is widely used in coatings, adhesives, and electronic chemicals. The stability of its preparation process and the efficiency of resource utilization directly affect the economics and feasibility of industrial production. Currently, industrially, HBE is mainly prepared by reacting 1,4-butanediol with acetylene in a catalytic system. This process typically includes core steps such as reaction, separation, and purification, requiring multi-unit synergy to achieve the preparation and recovery of the target product.

[0003] Existing preparation processes generally suffer from poor process continuity and low efficiency in the comprehensive utilization of raw materials. On the one hand, catalytic systems mostly use homogeneous catalysts or simple supported catalysts. The former is difficult to separate from the product, resulting in the inability to recover and reuse the catalyst, requiring frequent shutdowns to process materials and replenish the catalyst; the latter cannot be regenerated in time after its activity decays, which also affects the continuous progress of the process. On the other hand, the material circulation chain is imperfect, with missing or insufficient separation links for unreacted raw materials, and by-products are often directly discarded, leading to raw material waste. At the same time, distillation units mostly operate with fixed parameters, which cannot adapt to dynamic changes in feed composition and the proportion of recycled materials, easily causing incomplete separation or redundant energy consumption, further increasing the risk of process interruption and raw material loss, and restricting the economy and stability of industrial production. Summary of the Invention

[0004] To address the core issues of poor process continuity and low raw material utilization efficiency in the preparation of 4-hydroxybutylvinyl ether in existing technologies, this application provides a preparation process for 4-hydroxybutylvinyl ether. By constructing a closed-loop process system integrating catalytic regeneration, material recycling, and dynamic regulation, the process achieves synergistic optimization of continuous and stable operation and efficient reuse of raw materials.

[0005] A process for preparing a 4-hydroxybutyl vinyl ether includes the following steps:

[0006] S1. Catalyst preparation: Potassium hydroxide and 1,4-butanediol are mixed and loaded onto a porous support to form an immobilized catalyst, which is then activated.

[0007] S2, Nitrogen Replacement: The reaction system containing the activated catalyst is sequentially evacuated and then purged with nitrogen; the nitrogen gas containing impurities is removed and purified by adsorption and thermal regeneration before being recycled.

[0008] S3. Reactive distillation: In the reaction system after step S2, acetylene gas is continuously introduced and 1,4-butanediol is added. The synthesis reaction is carried out in a reactive distillation column under the action of a supported catalyst.

[0009] S4, Secondary Displacement: Transferring the liquid phase material after the synthesis reaction is completed to the separation system;

[0010] S5, Pre-distillation removal: The material transferred in step S4 is sent to the pre-distillation tower for separation. After the gas phase at the top of the tower is condensed, part of the material is returned to step S3.

[0011] S6. Diether distillation: The crude product obtained in step S5 is sent to a diether distillation column for separation. After condensation, part of the gas phase at the top of the column is returned to step S3.

[0012] S7. Transition component recovery: The liquid phase heavy component obtained in step S6 is sent to the recovery tower for separation, and the gas phase at the top of the tower is condensed and returned to step S6.

[0013] S8. Product distillation: The bottom material from step S7 is sent to a product distillation column for separation. The bottom material is divided into two parts: the first part is directly returned to step S3; the second part is the material containing the deactivated catalyst, which is sent to a regeneration distillation column for separation and recovery.

[0014] S9. Material purification: After collecting the various materials returned to step S3, they are filtered and adsorbed in sequence before entering the synthesis reaction.

[0015] S10, Byproduct Conversion: The byproduct diether is catalytically hydrogenated to obtain 1,4-butanediol, which is then added to the synthesis reaction in step S3.

[0016] By employing the above technical solution, potassium hydroxide and 1,4-butanediol are mixed, loaded onto a porous support, and activated. The porous support provides stable loading sites, achieving uniform dispersion and anchoring of potassium hydroxide and reducing the loss of active components. The loading method uses an equal-volume impregnation method, where the mixture of potassium hydroxide and 1,4-butanediol is precisely sprayed onto the surface of the porous support according to the carrier's absorption capacity, ensuring uniform loading. Activation treatment enhances the exposure of active sites. When the alkalinity of the reaction system decreases, a portion of the catalyst slurry is exported, replenished with potassium hydroxide-butanediol solution, and returned to the reaction system, achieving catalyst regeneration and reuse. Alkalinity is monitored using an online pH meter every 30 minutes, with the average alkalinity measured three times during the initial stage of the reaction used as the initial value. Reactive distillation is employed to simultaneously carry out the synthesis reaction and distillation separation within the distillation column, with the reaction products being immediately distilled off with the gas phase. A material circulation path is constructed through a pre-distillation column, a dual-ether distillation column, a recovery column, and a product distillation column. The condensate from the top of each separation unit or a portion of the bottom material is returned to the synthesis reaction stage. The returned material is purified by filtration and neutral alumina adsorption before entering the reaction. Filtration removes solid impurities and deactivated catalyst particles, while neutral alumina adsorbs trace organic impurities, polar impurities, and trace moisture. The byproduct dual-ether substances generated during separation are converted to 1,4-butanediol by catalytic hydrogenation and added to the synthesis reaction. The active sites of the hydrogenation catalyst promote the breaking of dual-ether bonds and hydrogenation reduction. Impurities such as oxygen are removed from the reaction system by purging with nitrogen after vacuuming. The nitrogen containing impurities is purified by adsorption and thermal regeneration and then recycled. The second purging uses the same operating parameters as the first purging. These technical units work together to form a closed-loop process chain, achieving the coordinated maintenance of catalytic activity, control of reaction equilibrium, material circulation, and resource utilization of byproducts through technologies such as supported catalysis, reactive distillation, multi-stage purification, and directional hydrogenation.

[0017] Preferably, in step S1, the porous support is selected from modified alumina, molecular sieve or activated carbon, the loading of potassium hydroxide on the supported catalyst is 5-25 wt%, the mixing temperature is 80-120℃, and the activation treatment time is 1-4 h.

[0018] By employing the above technical solution, modified alumina, molecular sieves, or activated carbon are selected as porous carriers. Their high specific surface area and abundant pore structure provide sufficient loading sites for potassium hydroxide, achieving uniform dispersion and firm anchoring of potassium hydroxide, and reducing the loss of active components. The potassium hydroxide loading is controlled at 5-25 wt%, ensuring sufficient active sites while preventing the aggregation of active components. Mixing is carried out at 80-120℃ using mechanical stirring at a rate of 300-500 r / min for 1-2 h to increase the molecular motion rate of the material, promote the full integration of potassium hydroxide and 1,4-butanediol, and ensure uniform loading. Activation is then performed for 1-4 h in a nitrogen atmosphere at a flow rate of 50-100 mL / min to remove residual moisture and impurities from the carrier surface, further activating the active sites of potassium hydroxide and increasing their exposure.

[0019] Preferably, in step S2, the vacuum is evacuated to a vacuum level of -0.08 MPa to -0.1 MPa, nitrogen is purged to a slightly positive pressure and maintained at 0.05 kPa to 0.5 kPa, and the replacement cycle is repeated 2 to 4 times, during which the oxygen content in the system is below 10 ppm; in the nitrogen purification cycle, the adsorption operation temperature is 25-40℃, and the thermal regeneration operation temperature is 120-150℃; in step S4, before the transfer of the liquid phase material, the separation system is first subjected to vacuuming and nitrogen purging operations in sequence; this operation is the same as in step S2.

[0020] By employing the above technical solution, a vacuum is drawn to -0.08 MPa to -0.1 MPa, maintained for 15-30 minutes each time, to remove air and other residual gases from the reaction system. Subsequently, nitrogen is purged to a slightly positive pressure of 0.05 kPa to 0.5 kPa at a rate of 20-50 mL / min, maintained for 20-40 minutes to maintain an inert atmosphere. Through 2 to 4 replacement cycles, the oxygen content in the system is controlled to be below 10 ppm, reducing the residual amount of oxygen and other impurities. In the nitrogen purification cycle, 3A molecular sieves are selected as the adsorbent. Adsorption operation at 25-40℃ ensures the adsorbent's adsorption efficiency for moisture and low-boiling-point organic matter entrained in nitrogen. Thermal regeneration operation at 120-150℃ desorbs impurities enriched on the adsorbent, restoring its performance and enabling nitrogen recycling. In step S4, before transferring the liquid material, the separation system undergoes the same vacuuming and nitrogen purging operations as in step S2 to ensure environmental consistency between the reaction system and the separation system, preventing contact with air or residual impurities within the separation system during material transfer. Through consistent process design and nitrogen circulation purification, an inert environment control chain is formed, encompassing replacement, purification, circulation, and secondary replacement. By controlling parameters such as pressure, temperature, and cycle count, synergistic effects of impurity removal, environmental stabilization, and resource reuse are achieved.

[0021] Preferably, in step S3, the reaction temperature of the synthesis reaction is 120-180℃ and the reaction pressure is 0.2-0.8MPa; in step S6, the top temperature of the diether distillation column is 65-85℃ and the bottom temperature is 150-180℃; in step S10, the reaction temperature of the hydrogenation conversion is 80-140℃, the reaction pressure is 1.0-3.0MPa, and the molar ratio of hydrogen to diether is 2:1 to 5:1.

[0022] By adopting the above technical solution, the temperature in the synthesis reaction stage is controlled at 120-180℃ to increase the molecular motion rate of acetylene and 1,4-butanediol, promoting the adsorption and reaction of reactants on the surface of the active sites of the supported catalyst. The acetylene introduction rate is 0.1-0.3 mol / (L·h), and the pressure is controlled at 0.2-0.8 MPa to increase the solubility of acetylene in the reaction system, maintain the stability of the reaction system, and create conditions for phase separation in reactive distillation. In the dual ether distillation stage, the dual ether distillation column adopts stainless steel corrugated packing with a packing height of 3-5m. The top temperature of the column is controlled at 65-85℃, and the bottom temperature is controlled at 150-180℃. The temperature gradient is formed by utilizing the boiling point difference between the dual ether and other components in the crude product, so that the dual ether preferentially vaporizes and distills out at the top of the column, while the heavy components remain in the bottom of the column. In the byproduct hydrogenation conversion stage, the temperature is controlled at 80-140℃ to activate the hydrogenation catalyst and promote the ether bond breaking and hydrogenation reduction reaction of the diethers; the pressure is controlled at 1.0-3.0 MPa to increase the solubility of hydrogen in the reaction system and enhance the contact reaction between hydrogen and the diethers; the molar ratio of hydrogen to diethers is controlled at 2:1 to 5:1 to ensure the sufficiency of the diether conversion. The synthesis reaction parameters determine the component characteristics of the subsequent separated materials, the diether distillation parameters provide stable and pure feedstock for the hydrogenation conversion, and the hydrogenation conversion parameters ensure the recovery of byproduct resources, forming a synergistic parameter chain of reaction, separation, and conversion.

[0023] Preferably, in step S3, the operating pressure of the reactive distillation column is 0.3-0.6 MPa, the top temperature is 70-95°C, and the bottom temperature is 150-170°C; the acetylene gas is introduced from the bottom of the column, and 1,4-butanediol and the catalyst are fed from the top of the column.

[0024] By adopting the above technical solution, the reactive distillation column uses a sieve tray column with 20-30 trays. The operating pressure of the reactive distillation column is controlled at 0.3-0.6 MPa, and the boiling points of each component in the column are adjusted to ensure that the synthesis reaction and distillation separation occur simultaneously within a suitable temperature range, maintaining the stability of the reaction system. A temperature gradient of 70-95℃ at the top of the column and 150-170℃ at the bottom of the column is used to achieve separation based on the difference in boiling points of the components. The low-boiling-point components generated in the reaction are preferentially vaporized and distilled off at the top of the column, while unreacted heavy components such as 1,4-butanediol are retained in the bottom of the column. Acetylene gas is introduced from the bottom of the column, while 1,4-butanediol and catalyst are fed from the top. The feed mass ratio of 1,4-butanediol to catalyst is 10:1 to 20:1, which allows the two reactants to form a countercurrent contact, increasing the contact area and contact time, and improving the mass and heat transfer efficiency. The catalyst flows downward with the 1,4-butanediol, continuously contacting the rising acetylene gas to fully exert its catalytic activity.

[0025] Preferably, in step S3, when the alkalinity of the synthesis reaction system is lower than 60-80% of its initial value, a portion of the catalyst slurry is exported and replenished with a potassium hydroxide-butanediol solution with a concentration of 10-30 wt%, and then the regenerated slurry is returned to the reaction system.

[0026] By adopting the above technical solution, during the synthesis reaction, the potassium hydroxide on the immobilized catalyst is consumed as the reaction proceeds, leading to a decrease in the system's basicity. When the system basicity falls below 60-80% of its initial value, the extracted catalyst slurry accounts for 10-20% of the total slurry in the reaction system. A portion of the extracted catalyst slurry is extracted, and a 10-30 wt% potassium hydroxide-butanediol solution is added. The added solution and the extracted slurry are stirred and mixed at 30-50°C for 30-60 minutes, and then the regenerated slurry is returned to the reaction system. The added solution within this concentration range can match the amount of active component missing in the catalyst slurry and replenish the lost potassium hydroxide. Through a dynamic control mode of basicity monitoring, partial extraction, precise replenishment, and recycling, the stability of the total amount and active state of the catalyst in the reaction system is maintained, achieving catalyst recycling and reducing catalyst loss.

[0027] Preferably, in step S8, the vapor phase collected from the top of the product distillation column is first separated by an organic vapor permeation membrane and then condensed to obtain the product; the operating temperature of the organic vapor permeation membrane separation is 40-70℃, and the vacuum degree behind the organic vapor permeation membrane is maintained at 5-20kPa.

[0028] By employing the above technical solution, the vapor phase collected from the top of the product distillation column is separated by an organic vapor permeation membrane and then condensed. The organic vapor permeation membrane is made of polyimide and achieves the separation of the target product from trace impurities based on the difference in permeation rates of different components within the membrane. The separation temperature of the organic vapor permeation membrane is controlled at 40-70℃ to balance the membrane's permeation performance and the vapor state of the components, ensuring the fluidity of the organic vapor and preventing membrane material performance degradation or component condensation clogging the membrane pores. A vacuum of 5-20 kPa is maintained behind the permeation membrane to create a pressure difference across the membrane, providing mass transfer power for the permeation and separation of the gas phase components, accelerating the permeation of the target product, and inhibiting the permeation of impurity components. Condensation is achieved using water cooling at a temperature of 0-10℃. The vapor phase separated by the permeation membrane is then condensed, causing the target product to precipitate in liquid form. Through a combined process of preliminary separation and enrichment by distillation, deep purification by permeation membrane, and condensation crystallization, a multi-stage purification synergy is formed.

[0029] Preferably, in step S9, the filtration uses a filter with a pore size of 0.1-0.5 μm, and the adsorption uses an adsorption column filled with neutral alumina; the operating temperature of the adsorption column is 50-80℃, the volume hourly space velocity of the material passing through the adsorption column is 1-3 h⁻¹, and the particle size of the neutral alumina is 100-300 mesh.

[0030] By employing the above technical solution, the recycled material from the synthesis reaction is pretreated through a ceramic filter with a pore size of 0.1-0.5 μm, allowing the material to pass through at a flow rate of 0.5-1 m / s, thus trapping solid particles and catalyst fragments in the system. The filtered material then enters an adsorption column filled with neutral alumina. The column diameter to height ratio is 1:10 to 1:15. Neutral alumina possesses suitable specific surface area and surface adsorption activity. The 100-300 mesh particle size design ensures the column packing density, preventing excessive bed resistance from affecting material flow while providing sufficient adsorption sites to adsorb trace polar impurities, organic byproduct fragments, and trace moisture from the recycled material. The adsorption column operating temperature is controlled at 50-80℃ to enhance the diffusion rate of impurity molecules on the adsorbent surface, maintaining adsorption equilibrium and adsorbent performance stability. The volume hourly space velocity (VHSV) of the material passing through the adsorption column is set at 1-3 h⁻¹ to balance the material throughput and adsorption contact time, ensuring sufficient contact between the material and the adsorbent. Deep purification of recycled materials is achieved through a progressive treatment process that first removes solid impurities, then removes trace amounts of organic and polar impurities.

[0031] Preferably, in step S10, the hydrogenation catalyst used for catalytic hydrogenation is a palladium-based catalyst or a nickel-based catalyst supported on an alumina support, wherein the loading of the active metal is 0.5-5 wt%.

[0032] By adopting the above technical solution, alumina is selected as the hydrogenation catalyst support. Its high specific surface area, stable crystal structure, and good mechanical strength provide uniform and robust loading sites for palladium-based or nickel-based active metals, preventing the agglomeration of active metal particles and ensuring stable dispersion of the active component. The chemical inertness of alumina prevents side reactions with the reaction system. The hydrogenation catalyst is prepared by an equal-volume impregnation method, in which an active metal salt solution is impregnated onto the alumina support, dried at 110℃ for 4 hours, and calcined at 500℃ for 3 hours. Palladium-based or nickel-based metals are selected as the catalytic active component. Their surface active sites can adsorb diethers and hydrogen molecules, promoting the breaking of ether bonds in the diether molecules and driving the hydrogenation reduction reaction to achieve the conversion of diether byproducts into 1,4-butanediol. The active metal loading is controlled at 0.5-5 wt% to ensure sufficient active sites while preventing metal particle agglomeration, thus balancing catalytic activity and resource utilization. The hydrogenation reaction adopts a fixed-bed reactor with a catalyst loading of 30-50% of the reactor volume. Through the synergistic design of carrier dispersion, directional catalysis of active components, and precise control of loading, the hydrogenation conversion reaction is stabilized and the reusability of catalyst is ensured.

[0033] Preferably, the heat medium supply of the reboiler in each of the following steps is adjusted according to the changes in the feed composition and the recycling ratio of each distillation column: the reactive distillation column in step S3, the dual ether distillation column in step S6, and the product distillation column in step S8.

[0034] By adopting the above technical solution, the feed to each distillation column comes from the preceding reaction or separation unit, including recycled materials. The feed composition and the recycling ratio of recycled materials change dynamically with the process operation. The feed composition is monitored in real time by an online gas chromatograph, with a monitoring frequency of once every hour. The recycling ratio of recycled materials is measured by a mass flow meter. Based on the real-time feed composition data and recycling ratio of each distillation column, the reboiler heat medium supply is adjusted: the heat medium supply is adjusted by 5-10% for every 10% change in feed composition or recycling ratio. For reactive distillation columns, the heat medium supply is adjusted to control the vapor-liquid balance and temperature gradient within the column to adapt to changes in the content of unreacted feedstock. For diether distillation columns, the heat medium supply is adjusted to adapt to changes in the diether content in the feed, maintaining a stable top temperature within the diether vaporization range. For product distillation columns, the heat medium supply is adjusted according to the enrichment degree of the target product in the feed to maintain a stable temperature gradient between the top and bottom of the column. By establishing a logical chain of feed status monitoring, heat medium supply matching, and separation effect assurance, the separation operation of each distillation column is matched with the material status, ensuring the stability of material flow between multi-stage separation units and achieving synergy between the separation system and the reaction and circulation processes.

[0035] In summary, this application has the following beneficial effects:

[0036] 1. Because this application adopts the core process of combining the preparation and regeneration of supported catalysts with reactive distillation, the material is recycled and reused through multiple steps such as pre-distillation and double ether distillation. It is equipped with material purification and by-product catalytic hydrogenation conversion and recovery processes. The heat medium supply of each distillation column is dynamically adjusted according to the feed and circulation ratio to achieve synergistic linkage of reaction, separation and resource recovery, thereby improving the continuity of the process and the comprehensive utilization efficiency of raw materials.

[0037] 2. In this application, potassium hydroxide is preferably supported on a porous support to form an immobilized catalyst. When the alkalinity of the reaction system decreases, the slurry is discharged for regeneration and alkali is added. The hydrogenation catalyst is a palladium-based or nickel-based catalyst supported on a specific support. Since the catalyst is immobilized, it is easy to separate and recover and maintain its activity through regeneration. The hydrogenation catalyst is adapted to the by-product conversion reaction, thus achieving the effect of ensuring the stability of catalytic efficiency.

[0038] 3. The method of this application involves separating the top gas phase of the product distillation column through an organic vapor permeation membrane and then condensing it. The material returned to step S3 is then purified by filtration and neutral alumina adsorption. Because the permeation membrane achieves precise purification, adsorption and filtration remove impurities from the circulating material, thus improving the product separation and purification effect.

[0039] 4. In the nitrogen replacement process of this application, the impurity-containing nitrogen is purified by adsorption and thermal regeneration and then recycled. The secondary replacement adopts the same standard operation as the primary replacement and maintains the low oxygen content of the system. Since the nitrogen resource is recycled and reused, and the low oxygen environment avoids the reaction from being interfered with by oxygen, the effects of saving resources and ensuring the stability of the reaction environment are achieved.

[0040] 5. In this application, the reboiler heat medium supply of the reaction distillation column, the dual ether distillation column and the product distillation column are adjusted according to the feed composition and the recycling ratio of the recycled material. Since the heat medium supply and the material state are dynamically matched, the stability of the separation efficiency of each distillation column is ensured, and the separation accuracy and process adaptability are improved. Attached Figure Description

[0041] Figure 1 This is a process flow diagram for the preparation of a 4-hydroxybutyl vinyl ether provided in this application. Detailed Implementation

[0042] The present application will be further described in detail below with reference to embodiments and comparative examples. Unless otherwise specified, the experimental methods used below are conventional methods. Unless otherwise specified, the materials, reagents, methods and instruments used are all conventional materials, reagents, methods and instruments in the art, which can be obtained by those skilled in the art through commercial channels or prepared according to literature methods.

[0043] Technical concept:

[0044] The core problems of existing 4-hydroxybutylvinyl ether preparation processes lie in poor process continuity and low raw material utilization efficiency, stemming from a lack of synergy in the technological system. From a catalytic perspective, the homogeneous catalysts used in traditional processes are difficult to separate from the products and cannot be recovered and reused, requiring frequent shutdowns to replenish the catalyst. Simple supported catalysts lack effective regeneration mechanisms after activity decay, leading to unsustainable reaction progression. From a material and separation perspective, a complete material recycling chain has not been established, resulting in incomplete recovery of unreacted raw materials and direct disposal of byproducts, causing significant waste. Simultaneously, the distillation unit operates with fixed parameters, failing to adapt to dynamic changes in feed composition and recycled material ratios. This leads to incomplete separation, increased energy redundancy, further disrupting process continuity and hindering improvements in raw material utilization efficiency.

[0045] This technical solution is centered on constructing a synergistic closed-loop system of catalysis, reaction, separation, and recovery, and addresses the aforementioned issues through a series of targeted technical means. It employs a combination of immobilized catalyst preparation and regeneration, using alkalinity monitoring to achieve targeted extraction, precise replenishment, and recycling of the catalyst slurry, maintaining stable catalytic activity and ensuring continuous reaction. It couples reactive distillation with multi-stage separation units such as pre-distillation and diether distillation, establishing a recycling pathway for unreacted raw materials. It incorporates filtration and adsorption purification processes to prevent impurities in the recycled materials from interfering with the reaction. A catalytic hydrogenation conversion stage is incorporated for the byproduct diethers, achieving targeted conversion of byproducts into raw materials and improving the resource recovery chain. Simultaneously, each distillation column dynamically adjusts the heat transfer medium supply based on the feed composition and recycling ratio, ensuring separation efficiency adapts to changes in material state. Ultimately, through the synergistic operation of all technical units, the dual goals of continuous and stable process operation and efficient raw material reuse are achieved.

[0046] Example 1: This example provides a preparation process for 4-hydroxybutyl vinyl ether. The raw material amounts are as follows: 100 kg of initial 1,4-butanediol, 7.5 kg of potassium hydroxide, acetylene is introduced at a molar ratio of 1.2:1 to 1,4-butanediol, 50 kg of porous support, and hydrogen is introduced at a molar ratio of 3.5:1 to the diether during the hydrogenation reaction.

[0047] The preparation process includes the following steps:

[0048] S1. Catalyst preparation: Potassium hydroxide and 1,4-butanediol are mixed and loaded onto a porous support to form an immobilized catalyst, which is then activated.

[0049] Among them, the porous support is a molecular sieve, the loading of potassium hydroxide on the immobilized catalyst is 15wt%, the mixing temperature is 100℃, and the activation treatment time is 2.5h.

[0050] S2, Nitrogen Replacement: The reaction system containing the activated catalyst is sequentially evacuated and then purged with nitrogen; the nitrogen gas containing impurities is removed and purified by adsorption and thermal regeneration before being recycled.

[0051] The process involves evacuating to a vacuum level of -0.09 MPa, purging with nitrogen to a slightly positive pressure and maintaining it at 0.275 kPa, and performing three replacement cycles. During the replacement process, the oxygen content in the system is below 10 ppm. In the nitrogen purification cycle, the adsorption operating temperature is 32.5℃, and the thermal regeneration operating temperature is 135℃.

[0052] S3. Reactive distillation: In the reaction system after step S2, acetylene gas is continuously introduced and 1,4-butanediol is added. The synthesis reaction is carried out in a reactive distillation column under the action of a supported catalyst.

[0053] The synthesis reaction is carried out at a temperature of 150℃ and a pressure of 0.5MPa. The reactive distillation column operates at a pressure of 0.45MPa, a top temperature of 82.5℃, and a bottom temperature of 160℃. Acetylene gas is introduced from the bottom of the column, while 1,4-butanediol and catalyst are fed from the top. When the alkalinity of the synthesis reaction system falls below 70% of its initial value, a portion of the catalyst slurry is removed, and a 20wt% potassium hydroxide-butanediol solution is added. The regenerated slurry is then returned to the reaction system. The reboiler heat transfer fluid supply is adjusted according to changes in the feed composition and the proportion of recycled materials.

[0054] S4, Secondary Displacement: Transferring the liquid phase material after the synthesis reaction is completed to the separation system;

[0055] Before transferring the liquid phase material, the separation system is first evacuated and then purged with nitrogen. This operation is the same as step S2, that is, evacuating to a vacuum degree of -0.09MPa, purging with nitrogen to maintain 0.275kPa, purging 3 times, the oxygen content in the system is less than 10ppm, and the nitrogen containing impurities is adsorbed at 32.5℃ and purified by thermal regeneration at 135℃ before being recycled.

[0056] S5, Pre-distillation removal: The material transferred in step S4 is sent to the pre-distillation tower for separation. After the gas phase at the top of the tower is condensed, part of the material is returned to step S3.

[0057] S6. Diether distillation: The crude product obtained in step S5 is sent to a diether distillation column for separation. After condensation, part of the gas phase at the top of the column is returned to step S3.

[0058] The top temperature of the dual ether distillation column is 75℃ and the bottom temperature is 165℃. The heat supply of the reboiler is adjusted according to the changes in the feed composition and the recycling ratio of the recycled material.

[0059] S7. Transition component recovery: The liquid phase heavy component obtained in step S6 is sent to the recovery tower for separation, and the gas phase at the top of the tower is condensed and returned to step S6.

[0060] S8. Product distillation: The bottom material from step S7 is sent to a product distillation column for separation. The bottom material is divided into two parts: the first part is directly returned to step S3; the second part is the material containing the deactivated catalyst, which is sent to a regeneration distillation column for separation and recovery.

[0061] In this process, the vapor phase collected from the top of the product distillation column is first separated by an organic vapor permeation membrane and then condensed to obtain the product. The operating temperature of the organic vapor permeation membrane is 55℃, and the vacuum degree behind the organic vapor permeation membrane is maintained at 12.5kPa. The heat medium supply of the reboiler is adjusted according to the changes in the feed composition and the recycling ratio of the recycled material in the product distillation column.

[0062] S9. Material purification: After collecting the various materials returned to step S3, they are filtered and adsorbed in sequence before entering the synthesis reaction.

[0063] The filtration process uses a filter with a pore size of 0.3 μm, and the adsorption process uses an adsorption column filled with neutral alumina. The operating temperature of the adsorption column is 65℃, the volume hourly space velocity of the material passing through the adsorption column is 2 h⁻¹, and the particle size of the neutral alumina is 200 mesh.

[0064] S10, Byproduct Conversion: The byproduct diether is catalytically hydrogenated to obtain 1,4-butanediol, which is then added to the synthesis reaction in step S3.

[0065] The hydroconversion reaction temperature was 110℃, the reaction pressure was 2.0 MPa, and the molar ratio of hydrogen to diether was 3.5:1. The hydrocatalyst used for catalytic hydrogenation was a palladium-based catalyst supported on an alumina support, with an active metal loading of 2.75 wt%.

[0066] Example 2: This example provides a preparation process for 4-hydroxybutyl vinyl ether. The raw material amounts are as follows: 100 kg of initial 1,4-butanediol, 2.5 kg of potassium hydroxide, acetylene is introduced at a molar ratio of 1.0:1 to 1,4-butanediol, 50 kg of porous support, and hydrogen is introduced at a molar ratio of 2:1 to the diether during the hydrogenation reaction.

[0067] The preparation process includes the following steps:

[0068] S1. Catalyst preparation: Potassium hydroxide and 1,4-butanediol are mixed and loaded onto a porous support to form an immobilized catalyst, which is then activated.

[0069] The porous support is modified alumina, the loading of potassium hydroxide on the immobilized catalyst is 5 wt%, the mixing temperature is 80℃, and the activation treatment time is 1 h.

[0070] S2, Nitrogen Replacement: The reaction system containing the activated catalyst is sequentially evacuated and then purged with nitrogen; the nitrogen gas containing impurities is removed and purified by adsorption and thermal regeneration before being recycled.

[0071] The process involves evacuating to a vacuum level of -0.1 MPa, purging with nitrogen to a slightly positive pressure and maintaining it at 0.05 kPa, performing two replacement cycles, and ensuring that the oxygen content in the system is below 10 ppm during the replacement process. In the nitrogen purification cycle, the adsorption operating temperature is 25°C, and the thermal regeneration operating temperature is 120°C.

[0072] S3. Reactive distillation: In the reaction system after step S2, acetylene gas is continuously introduced and 1,4-butanediol is added. The synthesis reaction is carried out in a reactive distillation column under the action of a supported catalyst.

[0073] The synthesis reaction is carried out at a temperature of 120℃ and a pressure of 0.2MPa. The reactive distillation column operates at a pressure of 0.3MPa, a top temperature of 70℃, and a bottom temperature of 150℃. Acetylene gas is introduced from the bottom of the column, while 1,4-butanediol and catalyst are fed from the top. When the alkalinity of the synthesis reaction system is lower than 60% of its initial value, a portion of the catalyst slurry is removed and replenished with a 10wt% potassium hydroxide-butanediol solution. The regenerated slurry is then returned to the reaction system. The reboiler heat transfer fluid supply is adjusted according to changes in the feed composition and the proportion of recycled materials.

[0074] S4, Secondary Displacement: Transferring the liquid phase material after the synthesis reaction is completed to the separation system;

[0075] Before transferring the liquid phase material, the separation system is first evacuated and then purged with nitrogen. This operation is the same as step S2, that is, evacuating to a vacuum of -0.1MPa, purging with nitrogen to maintain 0.05kPa, purging twice, the oxygen content in the system is less than 10ppm, and the nitrogen containing impurities is purified by adsorption at 25℃ and thermal regeneration at 120℃ before being recycled.

[0076] S5, Pre-distillation removal: The material transferred in step S4 is sent to the pre-distillation tower for separation. After the gas phase at the top of the tower is condensed, part of the material is returned to step S3.

[0077] S6. Diether distillation: The crude product obtained in step S5 is sent to a diether distillation column for separation. After condensation, part of the gas phase at the top of the column is returned to step S3.

[0078] The top temperature of the dual ether distillation column is 65℃ and the bottom temperature is 150℃. The heat supply of the reboiler is adjusted according to the changes in the feed composition and the recycling ratio of the recycled material.

[0079] S7. Transition component recovery: The liquid phase heavy component obtained in step S6 is sent to the recovery tower for separation, and the gas phase at the top of the tower is condensed and returned to step S6.

[0080] S8. Product distillation: The bottom material from step S7 is sent to a product distillation column for separation. The bottom material is divided into two parts: the first part is directly returned to step S3; the second part is the material containing the deactivated catalyst, which is sent to a regeneration distillation column for separation and recovery.

[0081] In this process, the vapor phase collected from the top of the product distillation column is first separated by an organic vapor permeation membrane and then condensed to obtain the product. The operating temperature of the organic vapor permeation membrane is 40℃, and the vacuum degree behind the organic vapor permeation membrane is maintained at 5kPa. The heat medium supply of the reboiler is adjusted according to the changes in the feed composition and the recycling ratio of the recycled material in the product distillation column.

[0082] S9. Material purification: After collecting the various materials returned to step S3, they are filtered and adsorbed in sequence before entering the synthesis reaction.

[0083] The filtration process uses a filter with a pore size of 0.1 μm, and the adsorption process uses an adsorption column filled with neutral alumina. The operating temperature of the adsorption column is 50℃, the volume hourly space velocity of the material passing through the adsorption column is 1 h⁻¹, and the particle size of the neutral alumina is 100 mesh.

[0084] S10, Byproduct Conversion: The byproduct diether is catalytically hydrogenated to obtain 1,4-butanediol, which is then added to the synthesis reaction in step S3.

[0085] The hydroconversion reaction temperature was 80℃, the reaction pressure was 1.0 MPa, and the molar ratio of hydrogen to diether was 2:1. The hydrogenation catalyst used was a nickel-based catalyst supported on an alumina support, with an active metal loading of 0.5 wt%.

[0086] Example 3: This example provides a preparation process for 4-hydroxybutyl vinyl ether. The raw material amounts are as follows: 100 kg of initial 1,4-butanediol, 12.5 kg of potassium hydroxide, acetylene is introduced at a molar ratio of 1.5:1 to 1,4-butanediol, 50 kg of porous support, and hydrogen is introduced at a molar ratio of 5:1 to the diether during the hydrogenation reaction.

[0087] The preparation process includes the following steps:

[0088] S1. Catalyst preparation: Potassium hydroxide and 1,4-butanediol are mixed and loaded onto a porous support to form an immobilized catalyst, which is then activated.

[0089] The porous support is activated carbon, the loading of potassium hydroxide on the immobilized catalyst is 25 wt%, the mixing temperature is 120℃, and the activation treatment time is 4 h.

[0090] S2, Nitrogen Replacement: The reaction system containing the activated catalyst is sequentially evacuated and then purged with nitrogen; the nitrogen gas containing impurities is removed and purified by adsorption and thermal regeneration before being recycled.

[0091] The process involves evacuating to a vacuum level of -0.08 MPa, purging with nitrogen to a slightly positive pressure and maintaining it at 0.5 kPa, performing four replacement cycles, and ensuring that the oxygen content in the system is below 10 ppm during the replacement process. In the nitrogen purification cycle, the adsorption operating temperature is 40°C, and the thermal regeneration operating temperature is 150°C.

[0092] S3. Reactive distillation: In the reaction system after step S2, acetylene gas is continuously introduced and 1,4-butanediol is added. The synthesis reaction is carried out in a reactive distillation column under the action of a supported catalyst.

[0093] The synthesis reaction is carried out at a temperature of 180℃ and a pressure of 0.8MPa. The reactive distillation column operates at a pressure of 0.6MPa, a top temperature of 95℃, and a bottom temperature of 170℃. Acetylene gas is introduced from the bottom of the column, while 1,4-butanediol and catalyst are fed from the top. When the alkalinity of the synthesis reaction system falls below 80% of its initial value, a portion of the catalyst slurry is removed, and a 30wt% potassium hydroxide-butanediol solution is added. The regenerated slurry is then returned to the reaction system. The reboiler heat transfer fluid supply is adjusted according to changes in the feed composition and the proportion of recycled materials.

[0094] S4, Secondary Displacement: Transferring the liquid phase material after the synthesis reaction is completed to the separation system;

[0095] Before the transfer of liquid phase materials, the separation system is first evacuated and purged with nitrogen in sequence. This operation is the same as step S2, that is, evacuating to a vacuum degree of -0.08MPa, purging with nitrogen to maintain 0.5kPa, purging 4 times, the oxygen content in the system is less than 10ppm, and the nitrogen containing impurities is purified by adsorption at 40℃ and thermal regeneration at 150℃ and then recycled.

[0096] S5, Pre-distillation removal: The material transferred in step S4 is sent to the pre-distillation tower for separation. After the gas phase at the top of the tower is condensed, part of the material is returned to step S3.

[0097] S6. Diether distillation: The crude product obtained in step S5 is sent to a diether distillation column for separation. After condensation, part of the gas phase at the top of the column is returned to step S3.

[0098] The top temperature of the dual ether distillation column is 85℃ and the bottom temperature is 180℃. The heat supply of the reboiler is adjusted according to the changes in the feed composition and the recycling ratio of the recycled material.

[0099] S7. Transition component recovery: The liquid phase heavy component obtained in step S6 is sent to the recovery tower for separation, and the gas phase at the top of the tower is condensed and returned to step S6.

[0100] S8. Product distillation: The bottom material from step S7 is sent to a product distillation column for separation. The bottom material is divided into two parts: the first part is directly returned to step S3; the second part is the material containing the deactivated catalyst, which is sent to a regeneration distillation column for separation and recovery.

[0101] In this process, the vapor phase taken from the top of the product distillation column is first separated by an organic vapor permeation membrane and then condensed to obtain the product. The operating temperature of the organic vapor permeation membrane is 70℃, and the vacuum degree behind the organic vapor permeation membrane is maintained at 20kPa. The heat medium supply of the reboiler is adjusted according to the changes in the feed composition and the recycling ratio of the recycled material in the product distillation column.

[0102] S9. Material purification: After collecting the various materials returned to step S3, they are filtered and adsorbed in sequence before entering the synthesis reaction.

[0103] The filtration process uses a filter with a pore size of 0.5 μm, and the adsorption process uses an adsorption column filled with neutral alumina. The operating temperature of the adsorption column is 80℃, the volume hourly space velocity of the material passing through the adsorption column is 3 h⁻¹, and the particle size of the neutral alumina is 300 mesh.

[0104] S10, Byproduct Conversion: The byproduct diether is catalytically hydrogenated to obtain 1,4-butanediol, which is then added to the synthesis reaction in step S3.

[0105] The reaction temperature for hydrogenation conversion is 140℃, the reaction pressure is 3.0MPa, and the molar ratio of hydrogen to diether is 5:1. The hydrogenation catalyst used for catalytic hydrogenation is a palladium-based catalyst supported on an alumina support, wherein the loading of the active metal is 5wt%.

[0106] Comparative Example 1: The only difference between this comparative example and Example 1 is that: in step S1, a supported catalyst is not used, but potassium hydroxide is directly dissolved in 1,4-butanediol to form a homogeneous catalytic system; accordingly, the catalyst slurry export and regeneration steps in step S3 are omitted, the treatment of the second part of the material in step S8 is changed to direct discharge or separate treatment, and the filtration and recovery of the supported catalyst is not included in step S9.

[0107] Comparative Example 2: The only difference between this comparative example and Example 1 is that in step S3, a reactive distillation column is not used, but the synthesis reaction is carried out in a conventional stirred tank reactor. After the reaction is completed, the entire reaction mixture is sent to the subsequent separation system. The feed to the pre-distillation column in step S5 is correspondingly changed to a complete reaction mixture.

[0108] Comparative Example 3: The only difference between this comparative example and Example 1 is that in step S8, the top vapor phase of the product distillation column does not pass through the organic vapor permeate membrane separator, but is directly collected as the product after only two stages of condensation.

[0109] Comparative Example 4: The only difference between this comparative example and Example 1 is that step S10 is omitted, and the by-product diethers separated in steps S6 and S7 are treated as waste and not subjected to hydrogenation conversion for recovery.

[0110] Experiment 1: Purity Test of 4-Hydroxybutylvinyl ether Product

[0111] Refer to the national standard GB / T30921.1-2014 "Test Methods for Purified Terephthalic Acid for Industrial Use - Part 1: Determination of Purity and Impurity Content by Gas Chromatography";

[0112] The purity of the 4-hydroxybutylvinyl ether products obtained in Examples 1-3 and Comparative Examples 1-4 was tested. The testing instrument was a gas chromatograph equipped with a flame ionization detector (FID), and the chromatographic column was an HP-5 capillary column with dimensions of 30 m × 0.32 mm × 0.25 μm. Before the experiment, each test sample was diluted with chromatographically pure methanol to a mass concentration of 10 mg / mL, and n-heptane was added as an internal standard at a mass ratio of 1:10. After thorough mixing, the samples were allowed to stand for 5 min. The chromatographic conditions were set as follows: initial column temperature 60 °C, held for 2 min, then increased to 200 °C at a rate of 10 °C / min, held for 5 min; injection port temperature 250 °C, detector temperature 280 °C; carrier gas was nitrogen, flow rate 1.0 mL / min, split ratio 20:1, and injection volume 1 μL. Each sample was measured in parallel three times, with an injection interval of 10 minutes between each injection. The peak area of ​​each component in the chromatogram was recorded. The mass fraction of 4-hydroxybutyl vinyl ether was calculated using the internal standard method. The average value of the three measurements was taken as the final purity data.

[0113] Experiment 2: Yield Test of 4-Hydroxybutylvinyl ether Reaction

[0114] Refer to the chemical industry standard HG / T2022-2018 "Calculation Method for Yield of Chemical Products";

[0115] The yields of 4-hydroxybutylvinyl ethers in Examples 1-3 and Comparative Example 144 were calculated and verified. Before each experiment, the initial mass of 1,4-butanediol was accurately weighed and recorded as m1; the total amount of acetylene introduced was accurately measured and converted from volume to mass under standard conditions, recorded as m2, thus determining 1,4-butanediol as the limiting feedstock. After the reaction, the purified 4-hydroxybutylvinyl ether product was obtained by distillation, and its mass was accurately weighed and recorded as m3; combined with the product purity measured in Experiment 1, recorded as w, the actual mass of 4-hydroxybutylvinyl ether produced, m4, was calculated, where m4 = m3 × w; based on the molecular formula of 4-hydroxybutylvinyl ether, C6H... 12 The molecular formulas of O2 and 1,4-butanediol are C4H4H2O. 10 O2 was used to calculate the theoretical yield of 1,4-butanediol completely converted to 4-hydroxybutylvinyl ether, denoted as m5. The reaction yield Y = (m4 / m5) × 100%. Each experiment was repeated three times in parallel. The amount of raw materials, reaction conditions and separation steps were strictly controlled for each experiment. The average of the three yield results was taken as the final data.

[0116] Experiment 3: 1,4-Butanediol Raw Material Utilization Rate Test

[0117] Referring to the national standard GB / T32268-2015 "General Rules for Material Balance in Chemical Processes", the utilization rate of 1,4-butanediol raw materials in Examples 1, 2, 3, Comparative Examples 1, 2, 3, and 4 was determined. During the experiments, the total mass of 1,4-butanediol initially input in each experiment was accurately measured and recorded as m0; the amount of 1,4-butanediol recycled back to the synthesis reaction in each step was collected and measured in real time, including the amount of condensate recycled in steps S5 and S6 (m6), the amount of bottom liquid recycled in step S8 (m7), and the mass of 1,4-butanediol recovered from the hydrogenation conversion of the byproduct in step S10 (m8); simultaneously, the mass of the 1,4-butanediol residue that did not participate in the recycling after the reaction was measured and recorded as m9; according to the principle of material balance, the total consumption of 1,4-butanediol was calculated as m0. 10 =m0+m6+m7+m8-m9, where m is the mass of 1,4-butanediol used to generate 4-hydroxybutyl vinyl ether. 11 Based on the actual yield m4 of Experiment 2, the 1,4-butanediol feedstock utilization rate U = (m 11 / m 10 ×100%. Each experiment was measured in parallel three times. The flow rate and mass data of each material were recorded throughout each experiment to ensure material balance closure. The average value of the three utilization rate results was taken as the final data.

[0118] The experimental data for the preparation process of 4-hydroxybutylvinyl ether are summarized in Table 1.

[0119] Table 1:

[0120] Experimental subjects 4-hydroxybutyl vinyl ether product purity (%) 4-hydroxybutyl vinyl ether reaction yield (%) 1,4-butanediol feedstock utilization (%) Example 1 99.5 88.5 93.5 Example 2 99.0 82.0 89.0 Example 3 99.7 90.0 95.0 Comparative Example 1 98.2 80.5 87.5 Comparative Example 2 97.8 75.2 83.0 Comparative Example 3 98.8 87.0 92.0 Comparative Example 4 99.4 88.2 85.8

[0121] As can be seen from Examples 1-3 and Comparative Example 1, and in conjunction with Table 1, the form in which the catalyst exists and the regeneration and recovery mechanism have a significant impact on the reaction process. Compared to homogeneous catalytic systems, using an immobilized catalyst with accompanying catalyst slurry regeneration and filtration recovery processes can influence the residual state of impurities in the reaction system and the maintenance of catalytic activity. Stable maintenance of catalytic activity ensures the continuous and efficient advancement of the reaction, while the immobilized form facilitates the separation of the catalyst from the product, reducing the introduction of catalytically related impurities into subsequent separation stages, thus forming a synergistic effect of catalysis and separation, affecting product performance and the effective utilization of raw materials.

[0122] As can be seen from Examples 1-3 and Comparative Example 2, and in conjunction with Table 1, the coupling mode of reaction and separation is a key factor affecting the reaction process. The reactive distillation column achieves simultaneous reaction and separation, which, compared to the conventional stirred tank reactor model of reaction followed by separation, allows for the timely removal of reaction products. Immediate product separation can alter the equilibrium state of the reaction system, reduce side reactions caused by product accumulation, and avoid secondary reactions resulting from prolonged coexistence of unreacted feedstock and product. This synergistic control of reaction and separation is directly related to the conversion efficiency of feedstock and the purity of product formation, thus affecting subsequent performance indicators.

[0123] As can be seen from Examples 1-3 and Comparative Example 3, and in conjunction with Table 1, the fineness of product separation and purification affects the relevant performance of the final product. The product's overhead vapor phase from the distillation column is separated by an organic vapor permeation membrane and then condensed, adding a targeted purification step compared to direct two-stage condensation. The organic vapor permeation membrane can selectively separate trace impurities in the vapor phase, further removing components that may affect product purity. This refined purification step synergistically works with the distillation separation, influencing the purity-related performance of the final product through multi-stage separation control, and also indirectly affecting the effective conversion and utilization of raw materials during the reaction process.

[0124] As can be seen from Examples 1-3 and Comparative Example 4, and in conjunction with Table 1, the by-product recycling mechanism is a key factor affecting the raw material utilization process. Catalytic hydrogenation of the by-product diethers and recovery of 1,4-butanediol for refueling in the synthesis reaction improves the raw material recycling pathway compared to directly treating the by-products as waste. The conversion and recovery of by-products allows previously lost raw materials to re-enter the reaction system, increasing the effective recycling volume and reducing ineffective consumption. This raw material-by-product-raw material cycle regulation, synergistically with the raw material conversion during the reaction process, affects the overall raw material utilization efficiency, and consequently relates to relevant performance indicators such as reaction yield.

[0125] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A process for preparing 4-hydroxybutylvinyl ether, characterized in that: Includes the following steps: S1. Catalyst preparation: Potassium hydroxide and 1,4-butanediol are mixed and loaded onto a porous support to form an immobilized catalyst, which is then activated. S2, Nitrogen Replacement: The reaction system containing the activated catalyst is sequentially evacuated and then purged with nitrogen; the nitrogen gas containing impurities is removed and purified by adsorption and thermal regeneration before being recycled. S3. Reactive distillation: In the reaction system after step S2, acetylene gas is continuously introduced and 1,4-butanediol is added. The synthesis reaction is carried out in a reactive distillation column under the action of a supported catalyst. S4, Secondary Displacement: Transferring the liquid phase material after the synthesis reaction is completed to the separation system; S5, Pre-distillation removal: The material transferred in step S4 is sent to the pre-distillation tower for separation. After the gas phase at the top of the tower is condensed, part of the material is returned to step S3. S6. Diether distillation: The crude product obtained in step S5 is sent to a diether distillation column for separation. After condensation, part of the gas phase at the top of the column is returned to step S3. S7. Transition component recovery: The liquid phase heavy component obtained in step S6 is sent to the recovery tower for separation, and the gas phase at the top of the tower is condensed and returned to step S6. S8. Product distillation: The bottom material from step S7 is sent to a product distillation column for separation. The bottom material is divided into two parts: the first part is directly returned to step S3; the second part is the material containing the deactivated catalyst, which is sent to a regeneration distillation column for separation and recovery. S9. Material purification: After collecting the various materials returned to step S3, they are filtered and adsorbed in sequence before entering the synthesis reaction. S10, Byproduct Conversion: The byproduct diether is catalytically hydrogenated to obtain 1,4-butanediol, which is then added to the synthesis reaction in step S3.

2. The preparation process of a 4-hydroxybutyl vinyl ether according to claim 1, characterized in that: In step S1, the porous support is selected from modified alumina, molecular sieve or activated carbon, the loading of potassium hydroxide on the supported catalyst is 5-25 wt%, the mixing temperature is 80-120℃, and the activation treatment time is 1-4 h.

3. The preparation process of a 4-hydroxybutyl vinyl ether according to claim 1, characterized in that: In step S2, the vacuum is evacuated to a vacuum level of -0.08 MPa to -0.1 MPa, and nitrogen is purged to a slightly positive pressure state and maintained at 0.05 kPa to 0.5 kPa. The replacement cycle is repeated 2 to 4 times, and the oxygen content in the system is below 10 ppm during the replacement process. In the nitrogen purification cycle, the adsorption operation temperature is 25-40℃, and the thermal regeneration operation temperature is 120-150℃. In step S4, before the liquid phase material is transferred, the separation system is first subjected to vacuuming and nitrogen purging operations in sequence. This operation is the same as in step S2.

4. The preparation process of a 4-hydroxybutyl vinyl ether according to claim 1, characterized in that: In step S3, the reaction temperature of the synthesis reaction is 120-180℃ and the reaction pressure is 0.2-0.8MPa; in step S6, the top temperature of the diether distillation column is 65-85℃ and the bottom temperature is 150-180℃; in step S10, the reaction temperature of the hydrogenation conversion is 80-140℃, the reaction pressure is 1.0-3.0MPa, and the molar ratio of hydrogen to diether is 2:1 to 5:

1.

5. The preparation process of a 4-hydroxybutyl vinyl ether according to claim 1, characterized in that: In step S3, the operating pressure of the reactive distillation column is 0.3-0.6 MPa, the top temperature is 70-95℃, and the bottom temperature is 150-170℃; the acetylene gas is introduced from the bottom of the column, and 1,4-butanediol and the catalyst are fed from the top of the column.

6. The preparation process of a 4-hydroxybutyl vinyl ether according to claim 1, characterized in that: In step S3, when the alkalinity of the synthesis reaction system is lower than 60-80% of its initial value, a portion of the catalyst slurry is exported and a 10-30 wt% potassium hydroxide-butanediol solution is added. The regenerated slurry is then returned to the reaction system.

7. The preparation process of a 4-hydroxybutyl vinyl ether according to claim 1, characterized in that: In step S8, the gas phase collected from the top of the product distillation column is first separated by an organic vapor permeation membrane and then condensed to obtain the product; the operating temperature of the organic vapor permeation membrane separation is 40-70℃, and the vacuum degree behind the organic vapor permeation membrane is maintained at 5-20kPa.

8. The preparation process of a 4-hydroxybutyl vinyl ether according to claim 1, characterized in that: In step S9, the filtration uses a filter with a pore size of 0.1-0.5μm, and the adsorption uses an adsorption column filled with neutral alumina; the operating temperature of the adsorption column is 50-80℃, the volume hourly space velocity of the material passing through the adsorption column is 1-3h⁻¹, and the particle size of the neutral alumina is 100-300 mesh.

9. The preparation process of a 4-hydroxybutyl vinyl ether according to claim 1, characterized in that: In step S10, the hydrogenation catalyst used for catalytic hydrogenation is a palladium-based catalyst or a nickel-based catalyst supported on an alumina support, wherein the loading of the active metal is 0.5-5 wt%.

10. The preparation process of a 4-hydroxybutyl vinyl ether according to claim 9, characterized in that: The heat medium supply to the reboiler of each distillation column is adjusted according to the changes in the feed composition and the recycling ratio of each column in the reactive distillation column in step S3, the dual ether distillation column in step S6, and the product distillation column in step S8.

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