Propyl acetate preparation reflux equipment and preparation process

Abstract

This invention discloses a reflux apparatus and process for preparing propyl acetate, relating to the field of propyl acetate preparation technology. The apparatus includes a distillation chamber and a condenser. A heater is installed at the bottom of the distillation chamber for heating. A cover is provided on the distillation chamber to seal the top opening, and a feed inlet is provided on one side of the chamber. A circular groove is formed at the center of the cover, and the condenser is embedded in the groove and extends into the distillation chamber. An air inlet is provided on the side of the condenser facing the distillation chamber. A main condenser tube is provided inside the condenser tube, and several sets of auxiliary condenser tubes connected to its bottom are arranged in a circumferential array outside the main condenser tube. A guide plate is provided on the side of the distillation chamber near the air inlet. The guide plate has a conical structure, and its outer edge slides against the side wall of the distillation chamber. An exhaust pipe is arranged at the center of the guide plate facing the air inlet, extending into the air inlet. Several sets of reflux holes are formed in a circumferential array near the edge of the guide plate.

Description

Technical Field

[0001] This invention relates to the field of propyl acetate preparation technology, specifically to a reflux apparatus and preparation process for propyl acetate preparation. Background Technology

[0002] Propyl acetate, also known as propyl acetate or n-propyl acetate, is a colorless, transparent liquid with a distinctive fruity aroma. This compound is obtained through the esterification reaction of acetic acid and n-propanol, exhibiting typical properties of esters. Propyl acetate is a colorless, transparent liquid at room temperature and is miscible with ethanol and diethyl ether. During its preparation, stirring is typically performed to promote mixing and contact of the reactants, thereby increasing the reaction rate and product yield. Furthermore, reflux is an important step in the preparation of propyl acetate, helping to remove the generated water and driving the reaction towards the formation of the product.

[0003] In the preparation of propyl acetate, reflux is primarily based on distillation and condensation: when acetic acid and propanol undergo esterification under reaction conditions to produce propyl acetate and water, the resulting volatile substances (mainly propyl acetate and some unreacted acetic acid and propanol) escape from the reaction system as the reaction proceeds. These volatile substances enter the condenser through a reflux pipe. In the condenser, the volatile substances are cooled, their temperature decreases, and they change from a gaseous state to a liquid state. This process is called condensation. The condensed liquid flows back into the reactor through the reflux pipe, mixing with the unreacted raw materials, thereby increasing the concentration of reactants and the reaction rate.

[0004] However, in practical applications, since the evaporated gas and the reflux liquid share the same channel, the condensed liquid will interfere with the entry of the evaporated gas into the condenser when it flows back into the reactor, thus affecting the condensation effect. Summary of the Invention

[0005] The purpose of this invention is to provide a reflux apparatus and process for preparing propyl acetate, thereby solving the following technical problems:

[0006] When the condensed liquid flows back into the reactor, it interferes with the entry of the evaporated gas into the condenser, affecting the condensation effect.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] A reflux apparatus for the preparation of propyl acetate includes a distillation chamber and a condenser, wherein a heater is provided at the bottom of the distillation chamber for heating the distillation chamber.

[0009] The distillation chamber is equipped with a cover for sealing the top opening, and a feed inlet is provided on one side of the chamber.

[0010] A circular groove is opened at the center end of the box cover, and the condenser is embedded in the circular groove and extends into the distillation box; an air inlet is provided on the side of the condenser facing the distillation box; a main condenser tube is provided inside the condenser tube, and several sets of auxiliary condenser tubes connected to its bottom are arranged in a circumferential array outside the main condenser tube.

[0011] A guide plate is provided on the side of the distillation chamber facing the air inlet. The guide plate has a conical structure and its outer edge slides against the side wall of the distillation chamber. An exhaust pipe is arranged at the center end of the guide plate facing the air inlet and extends into the air inlet. Several sets of reflux holes are arranged in a circumferential array near the edge of the guide plate, and a one-way valve is installed in the reflux holes.

[0012] It also includes a rotation module, which is used to drive the main condenser tube to rotate in the condenser cylinder.

[0013] Preferably, the main condenser is connected to the water inlet pump via the water inlet pipe, and the auxiliary condenser is connected to the circulation pump via the circulation pipe.

[0014] Preferably, a first condensing ring is fixedly arranged on the main condensing tube, and a second condensing ring fixed to the wall of the condensing cylinder is rotatably arranged on the first condensing ring. The second condensing ring is rotatably connected to the main condensing tube. Annular grooves are opened on the side of the first condensing ring and the second condensing ring that are close to each other. The two sets of annular grooves enclose a circulation cavity. One end of the circulation cavity is connected to each auxiliary condensing tube, and the other end is connected to the circulation tube.

[0015] Preferably, the rotating module includes a first gear fixedly mounted on the main condenser tube, a drive motor fixedly mounted on one side of the condenser cylinder, and a second gear meshing with the first gear fixedly mounted at the output end of the drive motor.

[0016] Preferably, the distillation tank is provided with a scraper that slides and fits against the inner wall of the distillation tank, and the scraper is fixed to the guide plate;

[0017] The guide plate is connected to the drive unit that drives its rotation.

[0018] Preferably, the driving unit includes a driving shaft fixedly arranged at the bottom end of the main condenser tube, a rotating wheel fixedly arranged at the end of the driving shaft, and several sets of cards fixedly arranged in a circumferential array on the rotating wheel;

[0019] The exhaust pipe has several sets of sliding grooves on its inner end face that correspond one-to-one with the cards and are slidably engaged.

[0020] Preferably, a positioning ring is slidably sleeved on the exhaust pipe, and several sets of positioning frames are fixedly arranged in a circumferential array on the positioning ring. A sealing ring is fixedly arranged on the positioning frame in the direction of the guide plate, and several sets of sealing rods for sealing the return hole are arranged in a circumferential array at the bottom of the sealing ring.

[0021] The positioning ring is connected to the lifting module, which is used to drive the sealing ring to rise and fall. A drain port is also opened on the side wall of the distillation tank to receive the propyl acetate left on the guide plate. A solenoid valve is installed between the drain ports.

[0022] Preferably, the lifting module includes a drive cylinder fixedly mounted on the box cover, and the drive cylinder is fixedly mounted on the lifting frame fixedly mounted on the condenser cylinder;

[0023] The exhaust pipe has several sets of strip-shaped slots arranged in a circumferential array on its outer end face, and the positioning ring has a corresponding slot seat that slides and engages with the strip-shaped slots on its inner end face. The exhaust pipe is also equipped with a return spring.

[0024] A process for preparing a reflux apparatus for propyl acetate preparation includes the following steps:

[0025] Acetic acid and propanol are added to the distillation tank through the feed inlet in accordance with the mass ratio;

[0026] The heater is started to heat the distillation chamber, and acetic acid and propanol react at the preset temperature to produce propyl acetate.

[0027] After propyl acetate is generated, it evaporates under high temperature, and the evaporated gas enters the condenser through the inlet.

[0028] The inlet pump delivers external cooling water to the main condenser and the auxiliary condenser to cool and liquefy the gas.

[0029] The drive motor is started to drive the second gear to rotate. During the rotation, the second gear meshes with the first gear to drive the main condenser tube to rotate.

[0030] Under the action of centrifugal force, the condensed liquid adhering to the surface of the main condenser and the auxiliary condenser is thrown onto the outer wall of the condenser cylinder, and then flows along the guide plate to the reflux hole and falls into the distillation chamber, thus achieving reflux;

[0031] After the reaction is complete, the drain port is opened by the solenoid valve, the lifting module drives the sealing ring to descend, the sealing rod seals the reflux hole, and the propyl acetate solution falls onto the guide plate and is discharged and collected along the drain port under the action of gravity.

[0032] After propyl acetate is collected, the heating temperature of the heater is increased to evaporate and condense the polymer before it is discharged.

[0033] The beneficial effects of this invention are:

[0034] (1) In this invention, the evaporated gas condenses and adheres to the main condenser and the auxiliary condenser. The main condenser and the auxiliary condenser are driven to rotate by the rotating module. Under the action of centrifugal force, the condensed liquid attached to the surface of the main condenser and the auxiliary condenser is thrown to the outer wall of the condenser cylinder. Since the diameter of the condenser cylinder is larger than the diameter of the exhaust pipe, the condensed liquid can fall directly onto the guide plate and then flow along the guide plate to the reflux hole. Finally, under the action of gravity, it falls back into the distillation chamber, achieving the effect of reflux. In this invention, the reflux of the liquid and the rise of the evaporated gas are independent of each other, and the liquid can flow back into the reaction liquid along the inner wall of the distillation chamber, making the flow direction more uniform and improving the subsequent reaction effect.

[0035] (2) In this invention, the cooling water in the auxiliary condenser is first input into the circulation chamber. The circulation pump draws the water out of the circulation chamber through the circulation pipe and cools it so that it can be drawn out and used by the subsequent water pump. Attached Figure Description

[0036] The invention will now be further described with reference to the accompanying drawings.

[0037] Figure 1 This is a schematic diagram of the structure of a reflux device for preparing propyl acetate according to the present invention;

[0038] Figure 2 This is a schematic diagram of the internal structure of a reflux device for preparing propyl acetate according to the present invention;

[0039] Figure 3 This is the present invention. Figure 2 A partially enlarged structural diagram at point A in the middle;

[0040] Figure 4 This is a schematic diagram of the condenser tube in a reflux apparatus for preparing propyl acetate according to the present invention;

[0041] Figure 5 This is a schematic diagram of the flow guide plate in a reflux device for preparing propyl acetate according to the present invention;

[0042] Figure 6 This is the present invention. Figure 2 A partially enlarged structural diagram at point B in the middle;

[0043] Figure 7 This is a process flow diagram of a reflux apparatus for preparing propyl acetate according to the present invention.

[0044] In the diagram: 1. Heater; 2. Distillation chamber; 3. Condenser; 4. First gear; 5. Main condenser; 6. Baffle plate; 7. Positioning ring; 201. Pressure relief valve; 202. Feed inlet; 203. Chamber cover; 401. Drive motor; 402. Second gear; 403. Water inlet pipe; 404. Circulation pipe; 405. Lifting frame; 406. Drive cylinder; 501. Auxiliary condenser; 502. Second condenser ring; 5 03. First condensation ring; 504. Circulation chamber; 505. Drive shaft; 506. Rotary wheel; 507. Card; 601. Return hole; 602. Positioning frame; 603. Solenoid valve; 604. Annular support; 605. Sealing rod; 606. Sealing ring; 607. Exhaust pipe; 608. Strip groove; 609. Slide groove; 610. Scraper; 611. Drain outlet; 701. Card holder; 702. Return spring. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] Example 1

[0047] Please see Figure 1 As shown, the present invention is a reflux apparatus for the preparation of propyl acetate, including a distillation chamber 2 and a condenser 3. A heater 1 is provided at the bottom of the distillation chamber 2 for heating the distillation chamber 2. In one embodiment of this invention, the distillation chamber 2 is configured as a cylindrical structure, and the heater 1 is a resistance heating device, the heating temperature of which can be adjusted according to actual application requirements.

[0048] A cover 203 for sealing the top opening is provided on the distillation chamber 2. A feed inlet 202 is provided on one side of the cover 203, which is connected to the inside of the distillation chamber 2 through a control valve. A pressure relief valve 201 is provided on the other side to monitor and adjust the pressure inside the distillation chamber 2. Specifically, the cover 203 is fixed to the distillation chamber 2 by several sets of positioning bolts. When preparing propyl acetate, acetic acid and propanol are added to the distillation chamber 2 through the feed inlet 202 in accordance with the mass ratio. The heater 1 is started to heat the distillation chamber 2, and the acetic acid and propanol react at the preset temperature to produce propyl acetate.

[0049] A circular groove is formed at the center end of the cover 203, and the condenser 3 is embedded in the groove and extends into the distillation chamber 2; please refer to Figure 2 Specifically, the condenser 3 has an air inlet on one side facing the distillation chamber 2; please refer to [link / reference]. Figure 4The condenser cylinder 3 is equipped with a main condenser pipe 5, which is connected to a water pump via a water inlet pipe 403. Several sets of auxiliary condenser pipes 501 connected to the bottom of the main condenser pipe 5 are arranged in a circumferential array on the outside of the main condenser pipe 5. The auxiliary condenser pipes 501 are connected to a circulation pump via a circulation pipe 404. It can be explained that after the raw material reacts in the distillation chamber 2 to produce propyl acetate, it evaporates under high temperature. The evaporated gas enters the condenser cylinder 3 through the air inlet. The water pump delivers external cooling water to the main condenser pipe 5 and the auxiliary condenser pipes 501 to cool and liquefy the gas. The water that has absorbed heat is extracted by the circulation pump for cooling again. After the propyl acetate is liquefied, it can fall back into the distillation chamber 2 through the air inlet to achieve reflux.

[0050] In this embodiment, please refer to Figure 5 A guide plate 6 is installed on the side of the distillation chamber 2 near the air inlet. The guide plate 6 has a conical structure, and its outer edge slides against the side wall of the distillation chamber 2. Please refer to [link / reference]. Figure 6 An exhaust pipe 607 is arranged at the center end of the guide plate 6 facing the air inlet, and the exhaust pipe 607 extends into the air inlet. The guide plate 6 has several sets of return holes 601 arranged in a circumferential array near the edge. A one-way valve is installed in the return hole 601, and the liquid can only flow into the distillation tank 2 through the return hole 601. It can be noted that the evaporated gas can enter the condenser 3 through the air inlet along the exhaust pipe 607. The diameter of the air inlet is larger than the diameter of the exhaust pipe 607.

[0051] It also includes a rotation module, which drives the main condenser 5 to rotate within the condenser cylinder 3. It should be noted that after evaporation, the gas condenses and adheres to the main condenser 5 and the auxiliary condenser 501. In this embodiment, the rotation module drives the main condenser 5 and the auxiliary condenser 501 to rotate. Under centrifugal force, the condensed liquid adhering to the surfaces of the main condenser 5 and the auxiliary condenser 501 is thrown onto the outer wall of the condenser cylinder 3. Since the diameter of the condenser cylinder 3 is larger than the diameter of the exhaust pipe 607, the condensed liquid can fall directly onto the guide plate 6, then flow along the guide plate 6 towards the reflux hole 601, and finally fall back into the distillation chamber 2 under gravity, achieving a reflux effect. In this embodiment, the reflux of the liquid and the rise of the evaporated gas are independent of each other, and the liquid can reflux back into the reaction liquid along the inner wall of the distillation chamber 2, resulting in a more uniform flow and improved subsequent reaction effects.

[0052] Example 2

[0053] Based on Example 1, an annular support 604 is fixedly arranged on the inner wall of the distillation chamber 2, and the outer edge of the guide plate 6 is placed on the annular support 604.

[0054] Please see Figure 3A first condensing ring 503 is fixedly arranged on the main condensing pipe 5. A second condensing ring 502, which is fixed to the wall of the condensing cylinder 3, is rotatably arranged on the first condensing ring 503. The second condensing ring 502 is rotatably connected to the main condensing pipe 5. Annular grooves are opened on the side of the first condensing ring 503 and the second condensing ring 502 that are close to each other. The two sets of annular grooves enclose a circulation chamber 504. One end of the circulation chamber 504 is connected to each auxiliary condensing pipe 501, and the other end is connected to the circulation pipe 404. It can be explained that the cooling water in the auxiliary condensing pipe 501 is first input into the circulation chamber 504. The circulation pump draws the water out of the circulation chamber 504 through the circulation pipe 404 for cooling, so that it can be drawn out and used by the subsequent water inlet pump.

[0055] Please see Figure 1 The rotating module includes a first gear 4 fixedly mounted on the main condenser tube 5, a drive motor 401 fixedly mounted on one side of the condenser cylinder 3, and a second gear 402 fixedly mounted at the output end of the drive motor 401 that meshes with the first gear 4. It can be understood that starting the drive motor 401 drives the second gear 402 to rotate, and the second gear 402 can drive the main condenser tube 5 to rotate by meshing with the first gear 4 during the rotation process.

[0056] Please see Figure 2 During the reaction process in the distillation chamber 2, some of the reaction liquid adheres to the inner wall of the distillation chamber 2 and cannot react. In this embodiment, a scraper 610 is provided inside the distillation chamber 2 and slides against the inner wall of the distillation chamber 2. The scraper 610 is fixed to the guide plate 6, and the guide plate 6 is connected to the drive unit that drives its rotation. It can be explained that during the reaction process, the drive unit drives the guide plate 6 to rotate, and the guide plate 6 simultaneously drives the scraper 610 to slide along the inner wall of the distillation chamber 2, scraping off the reaction liquid adhering to the inner wall of the distillation chamber 2, effectively avoiding the phenomenon that some reaction liquid cannot react in time.

[0057] Please see Figures 4-6 The drive unit includes a drive shaft 505 fixedly arranged at the bottom end of the main condenser pipe 5. A rotating wheel 506 is fixedly arranged at the end of the drive shaft 505. Several sets of cards 507 are fixedly arranged in a circumferential array on the rotating wheel 506. The inner end face of the exhaust pipe 607 is provided with several sets of sliding grooves 609 that correspond one-to-one with the cards 507 and are slidably engaged. It can be explained that when the main condenser pipe 5 rotates, it can synchronously drive the exhaust pipe 607 to rotate through the drive shaft 505, the rotating wheel 506 and the cards 507. The exhaust pipe 607 drives the scraper 610 to rotate through the guide plate 6, thereby achieving the effect of synchronous drive.

[0058] During the preparation of propyl acetate, high molecular weight polymers are generated as byproducts. These polymers are usually produced due to incomplete reaction of the raw materials, side reactions, or prolonged heating. Since these polymers typically have high boiling points, they can be separated from propyl acetate by distillation. During distillation, appropriate temperature and pressure are controlled to ensure that propyl acetate evaporates before the polymers, and the evaporated product is collected using a condenser. Specifically:

[0059] Please see Figures 5-6 A positioning ring 7 is slidably sleeved on the exhaust pipe 607. Several sets of positioning frames 602 are fixedly arranged in a circumferential array on the positioning ring 7. Sealing rings 606 are fixedly arranged on the positioning frames 602 towards the guide plate 6. Several sets of sealing rods 605 for sealing the return hole 601 are arranged in a circumferential array at the bottom of the sealing ring 606. The positioning ring 7 is connected to a lifting module, which drives the sealing ring 606 to rise and fall. Please refer to [link / reference]. Figure 2 The distillation chamber 2 also has a drain port 611 on its side wall to receive propyl acetate left on the guide plate 6. A solenoid valve 603 is installed between the drain ports 611. It can be noted that when in the reaction state, the sealing rod 605 is separated from the reflux hole 601. The drain port 611 is closed by the solenoid valve 603, and the condensed liquid can fall through the reflux hole 601.

[0060] After the reaction is complete, when separating propyl acetate and the polymer, the drain port 611 is opened by the solenoid valve 603, and the lifting module drives the sealing ring 606 to descend so that the sealing rod 605 seals the reflux hole 601. After the propyl acetate solution falls onto the guide plate 6, it can be discharged and collected along the drain port 611 under the action of gravity. After the propyl acetate is collected, the heating temperature of the heater 1 is increased and the polymer can be discharged by using this method.

[0061] Please see Figure 1 The lifting module includes a drive cylinder 406 fixedly mounted on the cover 203. The drive cylinder 406 is fixedly mounted on a lifting frame 405 fixedly mounted on the condenser cylinder 3. The outer end face of the exhaust pipe 607 has several sets of strip-shaped slots 608 arranged in a circumferential array. The inner end face of the positioning ring 7 is provided with a corresponding slot 701 that slides and engages with the strip-shaped slots 608. The exhaust pipe 607 is also provided with a return spring 702. Specifically, one end of the return spring 702 is fixed to the bottom of the exhaust pipe 607, and the other end is fixed to the positioning ring 7. It can be explained that when the sealing ring 606 is driven to descend, the drive cylinder 406 is first activated. The drive cylinder 406 drives the condenser cylinder 3 to descend through the lifting frame 405. The condenser cylinder 3 presses against the positioning frame 602, thereby driving the sealing ring 606 to move towards the return hole 601. During this process, the return spring 702 contracts to generate elastic force. When the condenser cylinder 3 rises, the return spring 702 can drive the positioning ring 7 to return to its original position.

[0062] In addition, this embodiment sets the card holder 701 to cooperate with the strip-shaped card slot 608 so that the positioning ring 7 can rotate synchronously when the exhaust pipe 607 rotates.

[0063] Please see Figure 7 A process for preparing a reflux apparatus for propyl acetate preparation includes the following steps:

[0064] S1. Acetic acid and propanol are added to the distillation tank 2 through the feed inlet 202 according to the mass ratio;

[0065] S2. Start heater 1 to heat distillation tank 2. Acetic acid and propanol react at the preset temperature to produce propyl acetate.

[0066] S3. After propyl acetate is generated, it evaporates under high temperature. The evaporated gas enters the condenser 3 through the air inlet.

[0067] S4. The water inlet pump delivers external cooling water to the main condenser 5 and the auxiliary condenser 501 to cool and liquefy the gas.

[0068] S5. Start the drive motor 401 to drive the second gear 402 to rotate. During the rotation, the second gear 402 can drive the main condenser tube 5 to rotate by meshing with the first gear 4.

[0069] S6. Under the action of centrifugal force, the condensed liquid adhering to the surface of the main condenser 5 and the auxiliary condenser 501 is thrown onto the outer wall of the condenser cylinder 3, and then flows along the guide plate 6 to the reflux hole 601 and falls into the distillation chamber 2 to achieve reflux.

[0070] S7. After the reaction is completed, the drain port 611 is opened by the solenoid valve 603. The lifting module drives the sealing ring 606 to descend. The sealing rod 605 seals the reflux hole 601. After the propyl acetate solution falls to the guide plate 6, it can be discharged and collected along the drain port 611 under the action of gravity.

[0071] After S8 and propyl acetate are collected, the heating temperature of heater 1 is increased to evaporate and condense the polymer before it is discharged.

[0072] In the description of this invention, it should be understood that the terms "upper," "lower," "left," and "right," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation or specific orientational structure and operation. Therefore, they should not be construed as limitations on the invention. Furthermore, "first" and "second" are only for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "multiple" means two or more.

[0073] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0074] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A reflux apparatus for preparing propyl acetate, comprising a distillation chamber (2) and a condenser (3), wherein a heater (1) is provided at the bottom of the distillation chamber (2) for heating the distillation chamber (2); The distillation chamber (2) is provided with a cover (203) for sealing the top opening, and a feed inlet (202) is provided on one side of the cover (203). Its features are, A circular groove is opened at the center end of the box cover (203), and the condenser (3) is embedded in the circular groove and extends into the distillation box (2); an air inlet is provided on the side of the condenser (3) facing the distillation box (2); a main condenser (5) is provided inside the condenser (3), and several sets of auxiliary condensers (501) connected to its bottom are arranged in a circumferential array on the outside of the main condenser (5). A guide plate (6) is provided on the side of the distillation chamber (2) near the air inlet. The guide plate (6) has a conical structure. The outer edge of the guide plate (6) slides against the side wall of the distillation chamber (2). An exhaust pipe (607) is arranged at the center end of the guide plate (6) towards the air inlet. The exhaust pipe (607) extends into the air inlet. Several sets of reflux holes (601) are opened in a circumferential array near the edge of the guide plate (6). A one-way valve is provided in the reflux hole (601). It also includes a rotation module, which is used to drive the main condenser tube (5) to rotate in the condenser cylinder (3); the guide plate (6) is connected to the drive unit that drives its rotation, the drive unit includes a drive shaft (505) fixedly arranged at the bottom end of the main condenser tube (5), a rotating wheel (506) fixedly arranged at the end of the drive shaft (505), and several sets of cards (507) fixedly arranged in a circumferential array on the rotating wheel (506); the inner end face of the exhaust pipe (607) is provided with several sets of sliding grooves (609) that correspond one-to-one with the cards (507) and slide and engage. The diameter of the condenser (3) is larger than the diameter of the exhaust pipe (607).

2. The reflux apparatus for preparing propyl acetate according to claim 1, characterized in that, The main condenser (5) is connected to the water inlet pump through the water inlet pipe (403), and the auxiliary condenser (501) is connected to the circulation pump through the circulation pipe (404).

3. The reflux apparatus for preparing propyl acetate according to claim 2, characterized in that, The main condenser tube (5) is fixedly provided with a first condensing ring (503), and a second condensing ring (502) fixed to the wall of the condensing cylinder (3) is rotatably provided on the first condensing ring (503). The second condensing ring (502) is rotatably connected to the main condenser tube (5). Annular grooves are opened on the side of the first condensing ring (503) and the second condensing ring (502) that are close to each other. The two sets of annular grooves enclose a circulation cavity (504). One end of the circulation cavity (504) is connected to each auxiliary condenser tube (501), and the other end is connected to the circulation tube (404).

4. The reflux apparatus for preparing propyl acetate according to claim 3, characterized in that, The rotating module includes a first gear (4) fixedly arranged on the main condenser tube (5), a drive motor (401) fixedly arranged on one side of the condenser cylinder (3), and a second gear (402) meshing with the first gear (4) fixedly arranged at the output end of the drive motor (401).

5. The reflux apparatus for preparing propyl acetate according to claim 4, characterized in that, The distillation chamber (2) is provided with a scraper (610) that slides and fits against the inner wall of the distillation chamber (2), and the scraper (610) is fixed to the guide plate (6).

6. The reflux apparatus for preparing propyl acetate according to claim 1, characterized in that, The exhaust pipe (607) is slidably fitted with a positioning ring (7), and a number of positioning frames (602) are fixedly arranged in a circumferential array on the positioning ring (7). A sealing ring (606) is fixedly arranged on the positioning frame (602) in the direction of the guide plate (6). A number of sealing rods (605) for sealing the return hole (601) are arranged in a circumferential array at the bottom of the sealing ring (606). The positioning ring (7) is connected to the lifting module, which is used to drive the sealing ring (606) to rise and fall. A drain port (611) is also opened on the side wall of the distillation tank (2) to receive the propyl acetate left on the guide plate (6). A solenoid valve (603) is set between the drain ports (611).

7. The reflux apparatus for preparing propyl acetate according to claim 6, characterized in that, The lifting module includes a drive cylinder (406) fixedly mounted on the box cover (203), and the drive cylinder (406) is fixedly mounted on the lifting frame (405) fixedly mounted on the condenser cylinder (3); Among them, the outer end face of the exhaust pipe (607) is provided with several sets of strip slots (608) in a circumferential array, the inner end face of the positioning ring (7) is provided with a corresponding slot seat (701) that slides and engages with the strip slots (608), and the exhaust pipe (607) is also provided with a return spring (702).

8. A preparation process for a reflux apparatus for preparing propyl acetate as described in any one of claims 1-7, characterized in that, Includes the following steps: Acetic acid and propanol are added to the distillation chamber (2) through the feed inlet (202) in the mass ratio; Start the heater (1) to heat the distillation tank (2), and acetic acid and propanol react at the preset temperature to generate propyl acetate; After propyl acetate is generated, it evaporates under high temperature, and the evaporated gas enters the condenser (3) through the air inlet; The water inlet pump delivers external cooling water to the main condenser (5) and the auxiliary condenser (501) to cool and liquefy the gas; Start the drive motor (401) to drive the second gear (402) to rotate. During the rotation, the second gear (402) can drive the main condenser (5) to rotate by meshing with the first gear (4). Under the action of centrifugal force, the condensed liquid adhering to the surface of the main condenser (5) and the auxiliary condenser (501) is thrown onto the outer wall of the condenser (3), and then flows along the guide plate (6) to the reflux hole (601) and falls into the distillation tank (2) to achieve reflux; After the reaction is completed, the drain port (611) is opened by the solenoid valve (603), the lifting module drives the sealing ring (606) to descend, the sealing rod (605) seals the reflux hole (601), and the propyl acetate solution falls to the guide plate (6) and is discharged and collected along the drain port (611) under the action of gravity. After the propyl acetate is collected, the heating temperature of the heater (1) is increased to evaporate and condense the polymer before it is discharged.

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