Apparatus and process for producing liquid crystal polymer precursor acetylated monomers

Abstract

The application discloses a production device and process of liquid crystal polymer precursor acetylation monomer, the device comprises a paddle reactor, the reaction monomer feed inlet of the paddle reactor is connected with a solid feeder, and an acetylation reagent atomizing nozzle is arranged at the feed inlet; a circulating gas inlet and a circulating gas outlet are arranged on the paddle reactor, the circulating gas inlet is sequentially connected with an acetic acid condenser, a tail gas absorption tank, a pressure stabilizing tank, a fan and a preheater, and the circulating gas outlet is connected with the circulating gas inlet; the horizontal paddle reactor is used instead of the traditional batch kettle reactor, a plurality of batch reactors are originally required to be connected in parallel for production, and now only one horizontal paddle reactor is required to complete the production, so that the equipment investment and production cost are reduced, and the production efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polymer material preparation, in particular to a production device and process of liquid crystal polymer precursor acetylated monomer. BACKGROUND

[0002] Liquid crystal polymer material (LCP) is a new type of material developed in the 1960s, which contains rigid rod-like or disc-like groups in the molecular chain and can form a liquid crystal phase in solution or molten state, thereby endowing this type of material with some unique properties. Since the liquid crystal polymer molecules contain heat-resistant aromatic ring structures, they not only have excellent heat resistance, dielectricity, mechanical properties, creep resistance, radiation resistance and chemical stability, but also have excellent mechanical properties and processability, and are a kind of engineering material with excellent performance, which is widely used in the fields of aviation, aerospace, transportation, chemical equipment and electronic industry, such as mobile phone antennas, flexible printed circuit boards and other industries.

[0003] There are many monomers for synthesizing aromatic polyester liquid crystals, which can be mainly divided into three types according to the properties of the functional groups of the monomers: AH type, in which one end of the aromatic ring is a hydroxyl group (H) and the other end is an acid group (A), such as p-hydroxybenzoic acid (HBA) and 2-yl-6-naphthoic acid (HNA); AA type, in which the aromatic ring contains two carboxylic acid groups, such as terephthalic acid (TPA), isophthalic acid, diphenyl dicarboxylic acid and 2,6-naphthalene dicarboxylic acid; and HH type, in which the aromatic ring contains two hydroxyl groups, such as p-benzenediol (HO), diphenylol (BP) and 2,6-naphthalenediol.

[0004] However, due to the low reactivity of the hydrogen atoms on the phenolic hydroxyl group-containing aromatic compounds, they cannot directly react to form liquid crystal polymers, and usually, the acetylation reaction is used to prepare aromatic compound monomers containing acetoxy groups with higher reactivity, and then the acetic acid is removed and high-temperature melting polymerization is performed to obtain the final liquid crystal polymer. For the synthesis of liquid crystal polymers with good comprehensive performance, high-purity acetylated products are particularly important.

[0005] The commonly used acetylation process uses a batch reaction kettle as the reaction container, and phenolic hydroxyl group-containing aromatic compounds and acetic anhydride as raw materials to react under the catalysis of alkali metal to produce acetyl aromatic compounds. The phenolic hydroxyl group-containing aromatic compounds and acetic anhydride are added together into the acetylation reaction kettle, and refluxed at 140-150℃ for 3-5 hours, and then the remaining acetic anhydride and the small molecular by-product acetic acid produced in the reaction are distilled out to obtain the acetylated product.

[0006] The prior art has the following problems: in the production process of the traditional acetylation reaction, the monomer is dissolved in acetic anhydride and reacts with acetic anhydride, since the dissolution of the monomer is an exothermic reaction, and the acetylation reaction is an endothermic reaction, which makes the temperature change range fluctuate greatly in the reaction process, and the reaction process is difficult to control the reaction temperature accurately, so that the reaction synchronism is poor.

[0007] In addition, the reaction is a reflux reaction at 140-150 DEG C, and the small molecular by-product acetic acid generated in the reaction exists in the reaction system all the time, which causes the increase of energy consumption in the process of continuous evaporation and condensation reflux, and the carboxyl of acetic acid reacts with the hydroxyl on the phenolic hydroxyl aromatic compound to generate ester, so that the by-product increases, the selectivity of the acetylation reaction is low, and it is difficult to prepare high-quality acetylated product, which seriously affects the product quality and performance of the subsequent synthesized liquid crystal polymer. SUMMARY

[0008] In view of the problems existing in the prior art, the present application provides a kind of liquid crystal polymer precursor acetylated monomer production device and process, make acetylation reagent and phenolic hydroxyl compound more fully mixed, improve production efficiency.

[0009] The technical scheme of the present application is as follows:

[0010] In the first aspect of the present application, a kind of liquid crystal polymer precursor acetylated monomer production device is provided, including paddle reactor, the reaction monomer feed inlet of the paddle reactor is connected with solid feeder, and the inlet is provided with acetylation reagent atomizing nozzle;The circulating gas inlet and circulating gas outlet are arranged on the paddle reactor, and the circulating gas inlet is connected with the circulating gas inlet in turn through acetic acid condenser, tail gas absorption tank, pressure stabilizing tank, fan and preheater.

[0011] In some embodiments of the present application, the acetylation reagent atomizing nozzle is a hollow cone nozzle, a solid cone nozzle, a spiral nozzle, a columnar nozzle or a two-fluid nozzle, and the acetylation reagent atomizing nozzle is connected with the acetylation reagent preheater through a pipeline.

[0012] In some embodiments of the present application, the paddle of the paddle reactor is a spiral ribbon paddle, a straight blade disc turbine paddle, a curved blade disc turbine paddle, a backswept paddle or a narrow blade airfoil paddle.

[0013] In some embodiments of the present application, baffles arranged in layers V are arranged on the upper and lower parts of the longitudinal section of the inner wall of the paddle reactor, and the distance between adjacent baffles is the same as the pitch of the spiral ribbon.

[0014] In some embodiments of the present application, the outer wall of the paddle reactor is provided with a jacket layer for circulating heat transfer medium, and the heat transfer medium is hot air, steam or heat conducting oil.

[0015] In some embodiments of the present application, a liquid mist demister is arranged at the circulating gas outlet of the paddle reactor.

[0016] In some embodiments of the present application, a reaction product discharge port is arranged at the bottom of the paddle reactor, and the reaction product discharge port is connected to a post-treatment system through a pipeline.

[0017] In the second aspect of the present application, a production process of liquid crystal polymer precursor acetylated monomers is provided, comprising the following steps:

[0018] The phenolic hydroxyl-containing aromatic compound enters the reaction monomer feed port through a solid feeder, and is preliminarily mixed with the preheated atomized acetylation reagent at the reaction monomer feed port;

[0019] The mixture enters the paddle reactor, and the acetylation reagent and the phenolic hydroxyl-containing aromatic compound are subjected to an acetylation reaction at a certain temperature, while the circulating gas enters the paddle reactor for closed-loop circulation, and the circulating gas carries the small molecular by-product acetic acid generated by the acetylation reaction out of the paddle reactor;

[0020] After the acetylation reaction is completed, the suspension of the acetoxy compound obtained by the reaction and the unreacted acetylation reagent is discharged to a post-treatment system.

[0021] In some embodiments of the present application, the temperature of the circulating gas is controlled at 120-140℃, and the circulating gas is one or a mixture of several of nitrogen, carbon dioxide, argon and helium.

[0022] In some embodiments of the present application, during the acetylation reaction, the temperature of the heat transfer medium in the jacket of the paddle reactor is controlled to maintain the reaction temperature in the paddle reactor at 115-135℃.

[0023] The one or more technical solutions of the present application have the following beneficial effects:

[0024] (1) The production device of liquid crystal polymer precursor acetylated monomers provided by the present application uses a horizontal paddle reactor instead of a traditional batch kettle reactor. Originally, multiple batch reactors were needed to be connected in parallel for production, and now only one horizontal paddle reactor is needed to complete the production, thereby reducing equipment investment and production cost and improving production efficiency.

[0025] (2) The production device for the acetylated monomer of the liquid crystal polymer precursor provided by the application is characterized in that an atomizing nozzle is arranged at the feeding port of the paddle reactor, and the acetylation reagent is atomized by the atomizing nozzle, and then collides with the loose and scattered phenolic hydroxyl compound to be mixed, and then enters the reactor, so that the feeding mode of the conventional acetylation process is changed, the acetylation reagent and the phenolic hydroxyl compound are mixed more fully, the uneven temperature distribution of the reaction system caused by the deposition of the reactants at the bottom of the reactor is avoided, and the dissolution time of the phenolic hydroxyl compound in the acetylation reagent is shortened, thereby improving the production efficiency.

[0026] (3) The production device for the acetylated monomer of the liquid crystal polymer precursor provided by the application is characterized in that a circulating gas is arranged to directly contact the reaction liquid with the circulating gas, so that the heat exchange effect is strengthened, and the small molecular by-product acetic acid generated in the reaction is timely removed, the occurrence of the side reaction is reduced, the product purity is improved, and the condensation reflux operation in the conventional production process is avoided, thereby reducing the energy consumption and production cost of the device.

[0027] (4) In the horizontal paddle reactor of the application, a wide propeller blade is used to increase the contact area of the reaction liquid and the heat transfer gas, and the mixing effect of the reaction liquid is strengthened. While stirring, the reaction liquid is thrown into the air along the tangent of the propeller blade, the contact time of the reaction liquid and the heat transfer gas is prolonged, and the heat transfer effect is further strengthened. Meanwhile, a baffle is arranged at the bottom of the longitudinal section of the paddle reactor, and the baffle forms a turbulent flow during stirring, thereby strengthening the mixing effect and making the reaction monomer concentration distribution uniform. A baffle is arranged at the upper part of the longitudinal section, and the reaction liquid thrown into the air by the stirring paddle collides with the upper baffle to form smaller reaction liquid droplets, thereby further increasing the contact area with the heat transfer gas and facilitating the mass and heat transfer.

[0028] (5) The production process for the acetylated monomer of the liquid crystal polymer precursor provided by the application is characterized in that the acetylation reagent is first atomized by an atomizing nozzle, and then collides with the loose and scattered phenolic hydroxyl compound to be mixed, and then the heat transfer medium is used to provide heat for the acetylation reaction process in the paddle reactor, and the reaction efficiency is further improved under the stirring action of the propeller blade. In the reaction process, the reaction liquid is directly contacted with the circulating gas by the circulating gas, the heat exchange effect is strengthened, and the small molecular by-product acetic acid generated in the reaction is timely removed. The process reduces the by-products, and high-quality acetylated products can be prepared. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The figure is a structural schematic diagram of the production device for the acetylated monomer of the liquid crystal polymer precursor.

[0030] In the figure: 1-acetylation reagent preheater, 2-solid feeder, 3-paddle reactor, 301-reaction monomer feeding port, 302-acetylation reagent atomizing nozzle, 303-circulating gas inlet, 304-motor, 305-paddle reactor jacket, 306-baffle, 307-stirring paddle, 308-liquid mist demister, 309-circulating gas outlet, 310-reaction product discharge port, 311-discharge valve, 4-acetic acid condenser, 5-tail gas absorption tank, 6-pressure stabilizing tank, 7-circulating fan, 8-circulating gas preheater, 9-post-treatment system. DETAILED DESCRIPTION

[0031] The application will be further described below in conjunction with the accompanying drawings and examples.

[0032] Example 1

[0033] In a typical embodiment of the application, a device for producing acetylated monomers of liquid crystal polymer precursor is provided, which comprises an acetylation reagent preheater 1, a solid feeder 2, a paddle reactor 3, an acetic acid condenser 4, a tail gas absorption tank 5, a pressure stabilizing tank 6, a circulating fan 7, a circulating gas preheater 8, and a post-treatment system 9.

[0034] The paddle reactor 3 serves as the cavity for the mixed reaction of reaction monomers, and a horizontal paddle reactor is used. The paddle reactor 3 is provided with a reaction monomer feeding port 301, which is connected to the solid feeder 2. The solid feeder can be a screw feeder, which is used to deliver the phenolic hydroxyl-containing aromatic compound into the reaction monomer feeding port at a calculated feeding amount. An acetylation reagent atomizing nozzle 302 is arranged at the reaction monomer feeding port 301, which is connected to the acetylation reagent preheater 1 through a pipeline. The preheated acetylation reagent is atomized by the atomizing nozzle and then enters the reaction monomer feeding port, collides with the phenolic hydroxyl-containing aromatic compound falling loosely into the reaction monomer feeding port 301, and then falls into the paddle reactor together after preliminary mixing.

[0035] In this embodiment, the acetylation reagent atomizing nozzle is a hollow cone nozzle, a solid cone nozzle, a spiral nozzle, a columnar nozzle, or a two-fluid nozzle.

[0036] The paddle reactor is provided with a circulating gas inlet 303 and a circulating gas outlet 309. The circulating gas inlet 309 is connected to the circulating gas inlet 303 in sequence through an acetic acid condenser 4, a tail gas absorption tank 5, a pressure stabilizing tank 6, a circulating fan 7, and a circulating gas preheater 8. A liquid mist demister 308 is arranged at the circulating gas outlet 309 for removing liquid droplets entrained in the circulating gas. The acetic acid condenser 4 is used to condense acetic acid gas entrained in the circulating gas. Most of the acetic acid gas is condensed in the acetic acid condenser and recovered as a byproduct of the acetylation reaction. A small amount of acetic acid gas is entrained in the circulating gas and enters the subsequent tail gas absorption tank for absorption. The absorption liquid used in the absorption tank is one or a plurality of water, NaOH solution, or KOH solution, and the Na(OH) solution is preferred. The purified pure circulating gas enters the pressure stabilizing tank to buffer the pressure fluctuation of the circulating gas. Then, under the action of the circulating fan 7, the circulating gas is delivered into the circulating gas preheater for preheating, thereby completing the closed-loop circulation and purification of the circulating gas.

[0037] In some embodiments of the present embodiment, the paddle of the paddle reactor is a spiral paddle, a straight-blade disc turbine paddle, a curved-blade disc turbine paddle, a swept-back paddle, or a narrow-blade airfoil paddle, and is preferably a spiral paddle. By using a wide spiral paddle design, the contact area between the reaction liquid and the heat transfer gas is increased, and the mixing effect of the reaction liquid is enhanced. While stirring, the reaction liquid is thrown into the air along the tangent of the spiral paddle, the contact time between the reaction liquid and the heat transfer gas is prolonged, and the heat transfer effect is further enhanced. The outer wall of the paddle reactor is provided with a paddle reactor jacket for circulating heat transfer medium to provide heat for the reaction process in the paddle reactor. The heat transfer medium is hot air, steam, or heat conducting oil, and is preferably steam. Further, the upper and lower parts of the longitudinal section of the inner wall of the paddle reactor are provided with V-shaped baffles 306 arranged in layers. The distance between adjacent baffles is the same as the pitch of the spiral. By arranging baffles at the bottom of the longitudinal section of the paddle reactor, a turbulent flow is formed during stirring, the mixing effect is enhanced, and the monomer concentration distribution is uniform. The reaction liquid thrown into the air by the stirring paddle collides with the upper baffles, forming smaller reaction liquid droplets, further increasing the contact area with the heat transfer gas, and facilitating mass and heat transfer. Therefore, the paddle reactor rapidly dissolves in the acetylation reagent by controlling the temperature of the heat transfer medium in the paddle reactor jacket to maintain the reaction temperature in the paddle reactor at 115-135°C.

[0038] The bottom of the paddle reactor is provided with a reaction product discharge port 310 connected with a post-treatment system 9 through a pipeline, and a screw discharge valve is arranged at the reaction product discharge port to realize the discharging process. Specifically, the post-treatment system comprises a centrifugal device, a drying device and an acetylated product storage device connected in sequence through pipelines, wherein the centrifugal device is used for performing solid-liquid separation on the acetoxy compound and the excess acetylation reagent which is not completely reacted, and then the acetoxy compound is washed by a washing liquid for 3-4 times, so that the acetylation reagent mixed in the acetoxy compound filter cake is washed clean, and then the acetoxy compound is introduced into the drying device to be dried to obtain a pure acetoxy compound.

[0039] In the embodiment, the horizontal paddle reactor is used instead of the traditional batch kettle reactor, and a plurality of batch reactors are connected in parallel to produce, and now only one horizontal paddle reactor is needed to complete the production, so that the equipment investment and production cost are reduced, and the production efficiency is improved. Meanwhile, the reaction liquid is directly contacted with the circulating gas by arranging the circulating gas, so that the heat exchange effect is strengthened, and the small molecule by-product acetic acid generated in the reaction is timely discharged, the occurrence of the side reaction is reduced, and the product purity is improved. Meanwhile, the condensation reflux operation in the conventional production process is avoided, and the device energy consumption and production cost are reduced.

[0040] Embodiment 2

[0041] In a typical embodiment of the present application, a production process of a liquid crystal polymer precursor acetylated monomer is provided, comprising the following steps:

[0042] (1) reaction monomer feeding: the phenolic hydroxyl-containing aromatic compound and the catalyst are transported into the reaction monomer feeding port by the solid feeder according to the calculated feeding amount, the acetylation reagent is transported into the acetylation reagent preheater by the metering pump according to the calculated feeding amount, is preheated to 110-130 DEG C, and then is introduced into the reaction monomer feeding port, and is atomized into small droplets by the acetylation reagent atomizing nozzle, collides with the loose falling phenolic hydroxyl aromatic compound introduced into the reaction monomer feeding port at the same time, is preliminarily mixed, and then falls into the paddle reactor.

[0043] (2) reaction monomer mixing reaction: the mixture of the acetylation reagent and the phenolic hydroxyl aromatic compound falls into the bottom of the paddle reactor, and is quickly dissolved in the acetylation reagent under the action of the special stirring paddle structure and the baffle, the reaction temperature in the paddle reactor is maintained at 115-135 DEG C by controlling the temperature of the heat transfer medium in the paddle reactor jacket, with the increase of the temperature of the reaction system, the acetylation reaction of the acetylation reagent and the phenolic hydroxyl aromatic compound is carried out, and the small molecule by-product acetic acid is released.

[0044] (3) Closed cycle of the circulating gas: the circulating gas is delivered into the circulating gas preheater by the circulating fan, heated to 120-140°C, and then enters the slurry reactor through the circulating gas inlet on the paddle reactor. The small molecule byproduct acetic acid gasified after the reaction enters the upper space of the paddle reactor and is carried by the circulating gas, which is then discharged through the circulating gas outlet into the acetic acid condenser. The condensing temperature is controlled at 90-110°C. Most of the acetic acid gas is condensed in the acetic acid condenser and recovered as the byproduct of the acetylation reaction. A small amount of acetic acid gas is carried by the circulating gas into the subsequent tail gas absorption tank for absorption using one or more of water, NaOH solution or KOH solution, preferably Na(OH) solution. The purified pure circulating gas enters the pressure stabilizing tank and is then delivered into the circulating gas preheater by the circulating fan, completing the closed cycle and purification of the circulating gas.

[0045] (4) Discharge of the reaction product: as the acetylation reaction proceeds, the phenolic hydroxyl aromatic compound is continuously acetylated into a compound containing acetoxy and precipitates from the reaction system. At the same time, the small molecule byproduct acetic acid produced by the reaction is continuously carried away by the circulating gas. When the reaction has been carried out for 3-5h, no acetic acid is condensed in the acetic acid condenser, indicating that the acetylation reaction has been completed. The discharge valve at the bottom of the paddle reactor is opened, and the suspension of the acetoxy compound and the unreacted acetylation reagent obtained by the reaction is discharged into the post-treatment section.

[0046] (5) Post-treatment of the reaction product: the suspension obtained by the reaction is first introduced into a centrifuge for solid-liquid separation of the acetoxy compound and the unreacted excess acetylation reagent. Then, the acetoxy compound is washed with a washing liquid for 3-4 times to wash away the acetylation reagent mixed in the acetoxy compound filter cake. After that, the acetoxy compound is introduced into a drying device and dried at 120-140°C for 2-3h to obtain a pure acetoxy compound.

[0047] In this embodiment, the temperature of the circulating gas is controlled at 120-140°C, and the circulating gas is one or a mixture of several of nitrogen, carbon dioxide, argon and helium.

[0048] In this embodiment, the temperature of the circulating gas is controlled at 120-140°C, and the circulating gas is one or a mixture of several of nitrogen, carbon dioxide, argon and helium.

[0049] In this embodiment, the phenolic hydroxyl aromatic compound can be one or several of p-hydroxybenzoic acid, 2-hydroxy-6-naphthoic acid and 4-hydroxy-4-carboxy biphenyl.

[0050] In this embodiment, the acetylation reagent can be one or several of acetic anhydride, propionic anhydride, phthalic anhydride and maleic anhydride, and acetic anhydride is preferably used.

[0051] In the present embodiment, the catalyst can be one or several of H2SO4, ZnCl2, FeCl3, zinc acetate, sodium acetate, preferably zinc acetate is used.

[0052] In a specific embodiment of the present embodiment:

[0053] The p-hydroxybenzoic acid and zinc acetate are mixed in proportion and fed into the solid feeder, and the feeding speed is controlled. The acetic anhydride is delivered by a metering pump in a calculated amount, heated to 120°C by a preheater, and then introduced into the spray head at the upper part of the horizontal paddle reactor, and the atomized acetic anhydride collides with the falling p-hydroxybenzoic acid solids to mix and fall into the lower part of the slurry reactor, where the acetylation reaction occurs under the action of the stirring paddle. The circulating gas is delivered from the pressure buffer tank to the circulating gas preheater by a circulating fan, preheated to 120°C, and then introduced into the paddle reactor to contact the reaction liquid thrown into the air by the stirring paddle for heat exchange, and at the same time, the small molecular by-product acetic acid in the reaction liquid is vaporized, and the gas is discharged at the gas outlet. The acetic acid vapor carried by the circulating air is condensed and recycled, and the condensing temperature is controlled at 100°C. The tail gas is absorbed by the absorption tank and returned to the pressure stabilizing tank to maintain the pressure stability of the entire system.

[0054] The steam temperature in the jacket of the paddle reactor is controlled at 100°C, and after 4 hours of reaction, the acetylation reaction is completed, and the reaction product is discharged through the discharge port screw unloading valve and sent to the post-treatment system. After being washed 3-4 times by a centrifuge, it is then dried in a drying device at 130°C for 2h, and the obtained acetyloxy compound is characterized by high performance liquid chromatography, and it is calculated that the purity of the 4-acetyloxybenzoic acid prepared in the present embodiment is 99.7%.

[0055] The above embodiments have described the technical solutions of the present application in detail, and it should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the present application. Any modification, supplement or similar replacement within the principle range of the present application should be included in the protection scope of the present application.

Claims

1. A process for producing a liquid crystalline polymer precursor acetylated monomer, characterized by, The application relates to a production device for an acetylated monomer of a liquid crystal polymer precursor, which comprises a paddle reactor, a solid feeder connected with a reaction monomer feeding port of the paddle reactor, and an acetylation reagent atomizing nozzle arranged at the feeding port; a circulating gas inlet and a circulating gas outlet are arranged on the paddle reactor, and the circulating gas inlet is connected with a vinegar acid condenser, a tail gas absorption tank, a pressure stabilizing tank, a fan and a preheater in sequence. The paddle of the paddle reactor is a spiral ribbon paddle. V-shaped baffles are arranged on the upper and lower parts of the longitudinal section of the inner wall of the paddle reactor, the distance between adjacent baffles is the same as the pitch of the spiral ribbon, and a jacket layer is arranged on the outer wall of the paddle reactor for circulating heat transfer medium, and the heat transfer medium is hot air, steam or heat conducting oil. The acetylation reagent atomizing nozzle is connected with an acetylation reagent preheater through a pipeline. The production process comprises the following steps: A phenolic hydroxyl-containing aromatic compound enters the reaction monomer feeding port through a solid feeder, is preliminarily mixed with preheated and atomized acetylation reagents at the reaction monomer feeding port, and a mixture is obtained; The mixture enters the paddle reactor, the acetylation reagents and the phenolic hydroxyl-containing aromatic compound are subjected to an acetylation reaction at a certain temperature, circulating gas enters the paddle reactor for closed loop circulation, and the circulating gas carries small molecule by-products acetic acid generated in the acetylation reaction out of the paddle reactor; After the acetylation reaction is completed, the suspension of acetyloxy compounds and unreacted acetylation reagents obtained in the reaction is discharged to a post-treatment system.

2. The process for producing a liquid crystalline polymer precursor acetylated monomer according to Claim 1, wherein The acetylation reagent atomizing nozzle is a hollow cone nozzle, a solid cone nozzle, a spiral nozzle, a columnar flow nozzle or a two-fluid nozzle.

3. The process for producing an acetylated monomer of a liquid crystalline polymer precursor according to Claim 1, wherein A liquid mist demister is arranged at the circulating gas outlet of the paddle reactor.

4. The process for producing an acetylated monomer of a liquid crystalline polymer precursor according to Claim 1, wherein A reaction product discharge port is arranged at the bottom of the paddle reactor, and the reaction product discharge port is connected with the post-treatment system through a pipeline.

5. The process for producing an acetylated monomer of a liquid crystalline polymer precursor according to Claim 1, wherein The temperature of the circulating gas is controlled to be 120-140 DEG C, and the circulating gas is one or a mixture of several of nitrogen, carbon dioxide, argon and helium.

6. The process for producing liquid crystalline polymer precursor acetylated monomers according to Claim 1, wherein, During the acetylation reaction, the temperature of the heat transfer medium in the jacket of the paddle reactor is controlled, so that the reaction temperature in the paddle reactor is maintained at 115-135 DEG C.

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