Preparation device and preparation method of medium-chain and long-chain alkyl naphthalene

Abstract

The invention relates to a preparation device and a preparation method of medium-chain and long-chain alkyl naphthalene. The preparation device comprises a reaction kettle, a catalyst tank, a first circulating pump, a heat exchanger, a second circulating pump, a condenser and an oil-water separator, wherein the reaction kettle, the first circulating pump and the heat exchanger form a first circulating system, and the reaction kettle, the second circulating pump, the condenser and the oil-water separator form a second circulating system. When the device disclosed by the invention is used for preparing medium-chain and long-chain alkyl naphthalene, firstly, a fresh ionic liquid catalyst is prepared through the catalyst tank, then the ionic liquid catalyst and reaction materials are sequentially added into the reaction kettle for reaction, and high-purity alkyl naphthalene is obtained through separation and purification after the reaction is finished. When the device is used for preparing the ionic liquid catalyst on site, the problem that the catalyst is easy to inactivate is avoided, meanwhile, water generated by reaction can be removed in time, forward proceeding of the reaction is promoted, and the utilization rate and the reaction efficiency of reactants can be further improved by arranging two independent circulating systems.

Description

Technical Field

[0001] The present invention belongs to the field of organic synthetic chemistry, and particularly relates to a preparation device for medium and long chain alkylnaphthalenes, and a method for efficiently preparing medium and long chain alkylnaphthalenes by Friedel-Crafts alkylation reaction using this device. Background Art

[0002] Alkylnaphthalenes are an important type of naphthalene-based chemical, which can be classified into short-chain alkylnaphthalenes, medium and long-chain alkylnaphthalenes, and long-chain alkylnaphthalenes according to the chain length of the substituent alkyl group. Among them, short-chain alkylnaphthalenes and long-chain alkylnaphthalenes have been relatively more studied and applied. For example, short-chain alkylnaphthalenes can be used as intermediates for the production of high-grade polymers, and long-chain alkylnaphthalenes are used for the synthesis of alkylnaphthalene sulfonic acid surfactants, etc. Relatively speaking, the research on the synthesis and application of medium and long-chain alkylnaphthalenes is relatively less.

[0003] Currently, the use of olefins as alkylating agents has been widely studied. However, olefins and naphthalene are prone to generate by-products during the reaction, while only water is produced as a by-product when fatty alcohols react with naphthalene. Therefore, it is very important to promptly remove the generated water to promote the forward movement of the reaction and thereby increase the content of alkylnaphthalenes in the product. However, the existing reaction devices basically concentrate the reaction materials in a single reaction kettle for reaction, and then perform oil-water separation on the reaction products after the reaction is complete, without considering the removal of the by-product water.

[0004] In addition, the catalysts currently used for the preparation of alkylnaphthalenes by Friedel-Crafts reaction (Friedel-Crafts reaction) are mainly liquid acidic catalysts, such as H 2 SO 4 、HF and CF 3 SO 3 H. However, these acidic solutions can cause serious equipment corrosion and environmental pollution. To overcome this drawback, some scholars have studied the use of solid catalysts. For example, Chinese Patent CN103664494B relates to a method for liquid-phase alkylation of naphthalene and propylene. Using naphthalene and propylene as raw materials, a zeolite containing organosilicon in its framework structure is used as a catalyst, at a reaction temperature of 150 - 300 °C, a reaction pressure of 1 - 3 Mpa, a molar ratio of naphthalene to propylene of 0.2 - 5:1, and a weight hourly space velocity of naphthalene of 0.1 - 10 hours -1The technical solution of the reaction under the conditions. This inventive method is only applicable to alkyl groups with 1 to 8 carbon atoms, preferably methyl or ethyl, and the reaction needs to be carried out under high temperature and high pressure conditions. Another example is Chinese Patent CN104817419B, which relates to a method for preparing alkylnaphthalene. The alkylnaphthalene contains one or more C4-C22 alkyl substituents that are the same as or different from each other. The method includes the following steps: in the presence of a gallium trifluoromethanesulfonate catalyst, naphthalene or α-methylnaphthalene or a mixture of naphthalene and α-methylnaphthalene undergoes an alkylation reaction with C4-C22 α-olefins to produce an alkylnaphthalene product. The disadvantages of this inventive method are that gallium trifluoromethanesulfonate catalyst is one of the known strongest acids, has strong corrosiveness and hygroscopicity, and when dissolved in polar organic solvents such as dimethylformamide, acetonitrile, and dimethyl sulfone during the reaction process, it releases heat violently, which may cause dangerous accidents. In addition, the alkylation reaction needs to be carried out under high pressure conditions (0.1 - 1.5 atm), and the reaction time is relatively long (6 - 16 hours).

[0005] Another example is Chinese Patent CN114507110A, which discloses a method for producing alkylnaphthalene. Using trifluoromethanesulfonic acid and / or methanesulfonic acid as catalysts, and naphthalene and olefins as raw materials, naphthalene, olefins, and the catalyst are stirred and mixed, and the temperature is controlled at 80 - 200 °C for 10 - 200 min; the reaction product is settled and separated into layers, and the upper oil phase and the lower catalyst phase are separated; an extractant is added to the oil phase, stirred for 1 - 20 minutes, and then settled and separated into layers to obtain an extractant phase and an oil phase; the extractant phase is heated and evaporated to recover the extractant and obtain the recovered catalyst; the oil phase is heated to evaporate and separate the residual extractant, unreacted naphthalene, and olefins to obtain alkylnaphthalene. The disadvantages of this patented method are low utilization rate of reaction materials, and since the reaction for preparing alkylnaphthalene is a reversible reaction, the water generated during the reaction process is not removed from the reaction system in time, thus limiting the content of the reaction product in the mixture.

[0006] Therefore, in recent years, some scholars have turned to developing ionic liquid catalysts. For example, Chinese Patent CN109824467A discloses a method for catalytically preparing polyalkylnaphthalene using ionic liquids: (1) preparing an ionic liquid catalyst with an acid stoichiometry of X; (2) according to the molar ratio of naphthalene:olefin of 1:1 to 1:10, first add naphthalene to the ionic liquid prepared in step (1), and then slowly drop the olefin into the mixture; (3) after the reaction is completed, cool the mixture to room temperature and separate it into layers; take the upper liquid product, wash it with water to remove a small amount of ionic liquid, then distill it under reduced pressure to remove the inert organic solvent and residual naphthalene, and then extract the liquid in the flask multiple times to obtain a polyalkylnaphthalene product. However, the disadvantages of this method are that only by improving the catalyst without improving the reaction device, it is impossible to overcome the inherent low utilization rate of reaction materials in organic reversible reactions, and if the by-products cannot be removed from the reaction system in time, it will limit the mass distribution of the reaction products in the reaction system. Summary of the Invention

[0007] Based on the technical problems existing in the prior art, the present invention has made two improvements to the prior art. On the one hand, a reaction device system with two circulation systems is designed, so that the by-product water in the system can be removed in time, promoting the forward reaction and improving the utilization rate of reaction materials; on the other hand, a freshly prepared green and mild ionic liquid catalyst is used, avoiding the corrosion of the catalyst to the storage container and the problem that the ionic liquid catalyst is easy to deactivate.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions.

[0009] A preparation device for medium and long-chain alkylnaphthalene, comprising a reaction kettle, a catalyst tank, a first circulation pump, a heat exchanger, a second circulation pump, a condenser and an oil-water separator. A spray nozzle is arranged at the top of the reaction kettle, and during the reaction process, the liquid reaction materials are dispersed and sprayed into the reaction kettle through the spray nozzle; the upper part of the reaction kettle is connected to the catalyst tank, and fresh ionic liquid catalyst is provided to the reaction kettle through the catalyst tank; the bottom of the reaction kettle is connected to the first circulation pump, and the liquid-phase reaction materials are continuously circulated in the device through the first circulation pump to participate in the reaction; the upper part of the reaction kettle is connected to the condenser, and an oil-water separator is arranged at the outlet of the condenser. The gas-phase reaction material mist generated in the upper space of the reaction kettle is sent to the condenser for condensation through the second circulation pump. After the condensate is separated by the oil-water separator, the oil-phase product flows back into the reaction kettle to continue to participate in the reaction, and the water-phase waste liquid is sent out of the reaction system.

[0010] In the above-mentioned preparation device for medium and long-chain alkylnaphthalene, the reaction kettle is connected to the catalyst tank, preventing the inactivation of the catalyst during transportation. Then, the reaction tank, the first circulation pump and the heat exchanger are sequentially connected to form a first closed circulation system. The first circulation pump is used to extract the liquid-phase reaction materials, so that the liquid-phase reaction materials are continuously circulated in the reaction system. There is a reaction raw material inlet on the right side of the reaction kettle, and a spray nozzle is arranged above the reaction kettle. The spray nozzle has a plurality of small holes with tiny apertures and arranged closely. During the reaction process, the materials are dispersed and sprayed through the spray nozzle, which can not only increase the contact area of the reactants, but also facilitate the extraction of the water generated in the second step of the reaction; the reaction kettle is sequentially connected to the second circulation pump, the condenser and the oil-water separator to form a second circulation system. The lower end of the condenser is in a conical structure, which is conducive to the reflux of the condensed liquid. The contact area with the mist can be increased in the middle part of the condenser to facilitate the liquefaction of the mist. After the condensed liquid is separated by the oil-water separator, the oil phase flows back into the reaction kettle to participate in the reaction again, and the water phase is separated into the storage tank. Among them, the first closed circulation system can work independently or work simultaneously with the second circulation system.

[0011] Further, the bottom of the spray nozzle has a porous structure with uniform distribution and close arrangement. During the reaction process, the liquid-phase material is dispersed and sprayed into the reaction kettle through the spray nozzle. Preferably, the spray holes on the spray nozzle are circular, with a pore diameter of 0.1 - 2 mm, the number of spray holes is 2 - 100, and the arrangement of the spray holes is one of equilateral triangle, equilateral quadrilateral (rhombus or square), equilateral pentagon, equilateral hexagon, circle, ring, and pentagram.

[0012] The present invention also relates to a method for preparing alkylnaphthalene. The molecular structural formula of the medium and long-chain alkylnaphthalene product is as follows:

[0013] Among them, R is an alkyl group with 10 - 20 carbon atoms; using the aforementioned preparation device for medium and long-chain alkylnaphthalene, it includes the following steps:

[0014] S1. The step of preparing an ionic liquid catalyst in the catalyst tank;

[0015] S2. The step of preparing alkylnaphthalene by Friedel - Crafts reaction in the reaction kettle using the ionic liquid catalyst;

[0016] And S3. The step of separating the product to obtain a high-purity alkylnaphthalene product.

[0017] Further, S1. The step of preparing an ionic liquid catalyst in the catalyst tank is specifically as follows: Fill the catalyst tank with nitrogen, then place anhydrous aluminum chloride and triethylamine hydrochloride with a molar ratio of 2.0:1 - 3.0:1 in the catalyst tank, and react for 4 h under the conditions of a reaction system pressure of 0.01 MPa and a reaction temperature of 80 °C to obtain a fresh ionic liquid catalyst.

[0018] Further, S2. The step of preparing alkylnaphthalene by Friedel - Crafts reaction in the reaction kettle using the ionic liquid catalyst is specifically as follows: Fill the reaction kettle with nitrogen, then add the ionic liquid catalyst to the reaction kettle, and then add reaction materials naphthalene, fatty alcohol, and an appropriate amount of organic solvent in a molar ratio of 1:1.20 - 1:1.25 in sequence, and react at a reaction temperature of 60 °C for 1 - 2 h to obtain a reaction product mainly composed of alkylnaphthalene.

[0019] Further, S3. The step of separating the product to obtain a high-purity alkylnaphthalene product is specifically as follows: Use an extractant to extract the reaction product obtained in S2 to remove the aqueous phase, and then rotary evaporate to remove the solvent, extractant, and residual fatty alcohol to obtain a high-purity alkylnaphthalene product. Preferably, the extractant is dichloromethane.

[0020] A preferred specific technical solution is that for the method for preparing alkylnaphthalene of the present invention, the molecular structural formula of the medium and long-chain alkylnaphthalene product is as follows:

[0021] Among them, R is an alkyl group with 10 to 20 carbon atoms;

[0022] Using the aforementioned preparation device for alkylnaphthalene, it is characterized by including the following steps:

[0023] S1. Open the nitrogen valve of the catalyst tank, conduct nitrogen replacement on the catalyst tank, and maintain the pressure in the catalyst tank at 0.01 MPa. Then, add anhydrous aluminum chloride and triethylamine hydrochloride into the catalyst tank for reaction to prepare an ionic liquid catalyst; among them, the molar ratio of anhydrous aluminum chloride to triethylamine hydrochloride is 2.0:1 to 3.0:1, the reaction temperature is 80 °C, and the reaction time is 4 h; and during the reaction process, ensure a closed reaction to prevent the inactivation of the catalyst activity;

[0024] S2. Open the nitrogen valve of the reaction kettle, conduct nitrogen replacement on the reaction kettle, and maintain the pressure in the reaction kettle at 0.01 MPa. Then, add the ionic liquid catalyst prepared in step S1 into the reaction kettle, and then add naphthalene, fatty alcohol, and solvent. Start the first circulation pump, and pump the liquid-phase material composed of naphthalene, fatty alcohol, solvent, and ionic liquid catalyst from the bottom of the reaction kettle through the first circulation pump into the heat exchanger to heat the liquid-phase material to the reaction temperature of 60 - 80 °C, and then disperse and spray it into the reaction kettle through the nozzle for reaction. The gaseous material mist generated in the reaction kettle is pumped out by the second circulation pump and sent to the condenser for condensation. The condensate is sent to the oil-water separator for water-oil separation. The temperature of the oil-water separator is controlled at 10 - 20 °C. The upper oil phase is used as the reaction material and refluxed to the reaction kettle to continue participating in the reaction, and the lower water phase is sent out of the reaction system as waste liquid; among them, the molar ratio of the reaction materials naphthalene to fatty alcohol is 1:1.20 to 1:1.25, the molar ratio of the ionic liquid catalyst to naphthalene is 8:1 to 12:1, the reaction temperature is 60 °C, and the reaction time is 1 - 2 h.

[0025] S3. After the reaction is completed, extract the water phase from the reaction product obtained in the reaction kettle with an extractant, and then remove the solvent, extractant, and residual fatty alcohol by rotary evaporation to obtain a high-purity alkylnaphthalene product; among them, the extractant used is dichloromethane.

[0026] In the above step S2, it is a continuous cyclic reaction. After the gaseous material mist is extracted and condensed, the lower water phase is separated out, and the oil phase is refluxed to the reaction kettle again to continue participating in the reaction, which can not only promote the reaction to proceed in the positive direction but also prevent the loss of effective components.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] 1) A reaction device system with two circulation systems is designed. The preparation process of alkylnaphthalene is carried out under the condition of continuous circulation of the reaction materials. On the one hand, it can timely remove the by-product water in the system, promote the forward reaction, and on the other hand, it effectively improves the utilization rate of the reaction materials and prevents the loss of effective components.

[0029] 2) The preparation of the ionic liquid catalyst is carried out in a closed-loop reaction device. Under the protection of inert gas, on the one hand, it can effectively prevent the problem that the catalyst is prone to deactivation, and on the other hand, it avoids the corrosion problem of the catalyst to the storage container.

[0030] 3) No additional organic solvent needs to be added during the preparation process of alkylnaphthalene, reducing the subsequent treatment and environmental pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the alkylnaphthalene preparation device of the present invention.

[0032] In the figure: 1 - catalyst tank; 2 - nozzle; 3 - reaction kettle; 4 - first circulation pump; 5 - heat exchanger; 6 - second circulation pump; 7 - condenser; 8 - oil-water separator. DETAILED DESCRIPTION OF THE INVENTION

[0033] The present invention will be further described below by examples, but is not limited to the following examples.

[0034] Figure 1 It is a schematic diagram of the alkylnaphthalene preparation device of the present invention. For the sake of clearly and briefly explaining the inventive concept of the present invention, the conventional settings such as the material inlet and outlet of the equipment in the figure are omitted, and the feeding or discharging methods such as upper, middle, and bottom feeding are adopted. Obviously, these settings belong to the common knowledge in the art, and those skilled in the art can reasonably select these conventional settings and their alternative setting methods according to the existing professional technical knowledge.

[0035] Such as Figure 1As shown in the figure, a preparation device for medium and long chain alkyl naphthalene includes a reaction kettle 3, a catalyst tank 1, a first circulation pump 4, a heat exchanger 5, a second circulation pump 6, a condenser 7 and an oil-water separator 8. A spray nozzle is arranged at the top of the reaction kettle 3, and during the reaction process, the liquid reaction material is dispersed and sprayed into the reaction kettle through the spray nozzle; the upper part of the reaction kettle is connected to the catalyst tank 1, and fresh ionic liquid catalyst is provided to the reaction kettle 3 through the catalyst tank 1; the bottom of the reaction kettle is connected to the first circulation pump 4, and the liquid-phase reaction material is continuously circulated in the device through the first circulation pump 4 to participate in the reaction, forming a first closed circulation system; the upper part of the reaction kettle is connected to the condenser 7, and an oil-water separator 8 is arranged at the outlet of the condenser. The gas-phase reaction material mist generated in the upper space of the reaction kettle is sent to the condenser for condensation through the second circulation pump. After the condensate is separated by the oil-water separator, the oil-phase product flows back into the reaction kettle to continue participating in the reaction, and the water-phase waste liquid is sent out of the reaction system, forming a second closed circulation system. Among them, the first closed circulation system can work independently or work simultaneously with the second circulation system.

[0036] In the present invention, in the above specific reaction device, the catalyst tank 1 and the reaction kettle 3 are successively filled with inert gas nitrogen, and then anhydrous aluminum chloride and triethylamine hydrochloride are put into the catalyst tank 1 for reaction in a certain proportion to prepare a chloroaluminate ionic liquid catalyst. Then the catalyst is added to the reaction kettle 3, and then naphthalene and fatty alcohol are successively added for catalysis, and a Friedel-Crafts reaction occurs to obtain alkyl naphthalene. The obtained mixture is extracted with an extractant for several times to remove the residual water phase, and finally the solvent is removed by rotary evaporation to obtain a high-purity alkyl naphthalene product. The following further combines the drawings to illustrate the embodiments of the present invention in detail by way of examples.

[0037]

Example 1

[0038] Open the nitrogen valve of the catalyst tank 1, conduct nitrogen replacement on the catalyst tank 1, and maintain the pressure in the catalyst tank 1 at 0.01 MPa. Then add anhydrous aluminum chloride and triethylamine hydrochloride to the catalyst tank 1 in a molar ratio of 2.0:1. The reaction temperature is 80 °C and the reaction time is 4 h. During the reaction process, ensure a closed reaction to prevent the inactivation of the catalyst activity. Open the nitrogen valve of the reaction kettle 3, conduct nitrogen replacement in the reaction kettle, and maintain the pressure in the reaction kettle at 0.01 MPa. Then mix naphthalene and n-decanol in a molar ratio of 1:1.25, add solvent oil accounting for 80% of the total weight of the mixed solution to the mixed solution, and after mixing evenly at a temperature of 60 °C under the protection of inert gas, add an ionic liquid catalyst to the above mixed solution. The molar ratio of the ionic liquid catalyst to naphthalene is 8:1. Start the first circulation pump 4, and pump the liquid-phase material composed of naphthalene, n-decanol, solvent, and ionic liquid catalyst from the bottom of the reaction kettle 3 through the first circulation pump 4 into the heat exchanger 5 to heat the liquid-phase material to the reaction temperature of 60 °C, and then spray it into the reaction kettle 3 through the nozzle 2 for dispersion and reaction. The gas-phase material mist generated in the reaction kettle 3 is pumped out by the second circulation pump 6 and sent to the condenser 7 for condensation. The condensate is sent to the oil-water separator 8 for water-oil separation. The temperature of the oil-water separator 8 is controlled at 10-20 °C. The upper oil phase is returned to the reaction kettle 3 as reaction material to continue participating in the reaction, and the lower water phase is sent out of the reaction system as waste liquid. After cyclic reaction for 2 h, the reaction product obtained in the reaction kettle 3 is extracted with an extractant to remove the water phase, and then the solvent, extractant, and residual n-decanol are removed by rotary evaporation to obtain high-purity 1-n-decylnaphthalene.

[0039]

Example 2

[0040] Open the nitrogen valve of the catalyst tank 1, conduct nitrogen replacement on the catalyst tank 1, and maintain the pressure in the catalyst tank 1 at 0.01 MPa. Then add anhydrous aluminum chloride and triethylamine hydrochloride into the catalyst tank 1 at a molar ratio of 2.5:1. The reaction temperature is 80 °C and the reaction time is 4 h. During the reaction process, ensure a closed reaction to prevent the inactivation of the catalyst activity. Open the nitrogen valve of the reaction kettle 3, conduct nitrogen replacement on the reaction kettle 3, and maintain the pressure in the reaction kettle 3 at 0.01 MPa. Then mix naphthalene and dodecanol at a molar ratio of 1:1.25, add solvent oil accounting for 80% of the total weight of the mixed solution to the mixed solution, mix evenly at a temperature of 60 °C under the protection of inert gas, and then add an ionic liquid catalyst to the above mixed solution. The molar ratio of the ionic liquid catalyst to naphthalene is 10:1. Start the first circulation pump 4, pump the liquid-phase material composed of naphthalene, dodecanol, solvent and ionic liquid catalyst from the bottom of the reaction kettle 3 through the first circulation pump 4 into the heat exchanger 4 to raise the temperature of the liquid-phase material to the reaction temperature of 60 °C, and then spray it into the reaction kettle 3 through the nozzle 2 for dispersion to carry out the reaction. The gaseous material mist generated in the reaction kettle 3 is pumped out by the second circulation pump 6 and sent to the condenser 7 for condensation. The condensate is sent to the oil-water separator 8 for water-oil separation. The temperature of the oil-water separator 8 is controlled at 10-20 °C. The upper oil phase is refluxed to the reaction kettle 3 as reaction material to continue participating in the reaction, and the lower water phase is sent out of the reaction system as waste liquid. After 2 h of cyclic reaction, the reaction product obtained in the reaction kettle 3 is extracted with an extractant to remove the water phase, and then the solvent, extractant and residual decanol are removed by rotary evaporation to obtain high-purity 1-dodecylnaphthalene.

[0041]

Example 3

[0042] Open the nitrogen valve of the catalyst tank 1, conduct nitrogen replacement on the catalyst tank, and maintain the pressure in the catalyst tank 1 at 0.01 MPa. Then add anhydrous aluminum chloride and triethylamine hydrochloride into the catalyst tank 1 in a molar ratio of 3.0:1. The reaction temperature is 80 °C and the reaction time is 4 h. During the reaction process, ensure a closed reaction to prevent the inactivation of the catalyst activity. Open the nitrogen valve of the reaction kettle 3, conduct nitrogen replacement on the reaction kettle 3, and maintain the pressure in the reaction kettle 3 at 0.01 MPa. Then mix naphthalene and tetradecanol in a molar ratio of 1:1.25, add solvent oil accounting for 80% of the total weight of the mixed solution to the mixed solution. After mixing evenly at a temperature of 60 °C under the protection of inert gas, add an ionic liquid catalyst to the above mixed solution. The molar ratio of the ionic liquid catalyst to naphthalene is 12:1. Start the first circulation pump 4, and pump the liquid-phase material composed of naphthalene, tetradecanol, solvent and ionic liquid catalyst from the bottom of the reaction kettle 3 through the first circulation pump 4 into the heat exchanger 5, so that the liquid-phase material is heated to the reaction temperature of 60 °C, and then is dispersed and sprayed into the reaction kettle 3 through the nozzle 2 for reaction. The gaseous material mist generated in the reaction kettle 3 is pumped out by the second circulation pump 6 and sent to the condenser 7 for condensation. The condensate is sent to the oil-water separator 8 for water-oil separation. The temperature of the oil-water separator 8 is controlled at 10-20 °C. The upper oil phase is returned to the reaction kettle 3 as reaction material to continue participating in the reaction, and the lower water phase is sent out of the reaction system as waste liquid. After circulating the reaction for 2 h, the reaction product obtained in the reaction kettle 3 is extracted with an extractant to remove the water phase, and then the solvent, extractant and residual n-decanol are removed by rotary evaporation to obtain high-purity 1-tetradecylnaphthalene.

Claims

1. A device for preparing medium and long chain alkyl naphthalene, characterized in that: The invention comprises a reactor (3), a catalyst tank (1), a first circulation pump (4), a heat exchanger (5), a second circulation pump (6), a condenser (7) and an oil-water separator (8); a spray nozzle (2) is arranged on the top of the reactor, and during the reaction process, liquid reaction materials are dispersed and sprayed into the reactor (3) through the spray nozzle (2); the upper part of the reactor is connected to the catalyst tank (1), and fresh ionic liquid catalyst is provided to the reactor (3) through the catalyst tank (1); the bottom of the reactor (3) is connected to the first circulation pump (5), and the second circulation pump (6) is connected to the second circulation pump (7), and the second circulation pump (8) is connected to the second circulation pump (9); the second circulation pump (10) is connected to the second circulation pump (11); the second circulation pump (11) is connected to the second circulation pump (9); the second circulation pump (12) is connected to the second circulation pump (13); the second circulation pump (14) is connected to the second circulation pump (15); the second circulation pump (16) is connected to the second circulation pump (17); the second circulation pump (18) is connected to the second circulation pump (19); the second circulation pump (19) is connected to the second circulation pump (21); the second circulation pump (11) is connected to the second circulation pump (22); the second circulation pump (14) is connected to the second circulation pump (23); the second circulation pump (15) is connected to the second circulation pump (24); the second circulation pump (16) is connected to the second circulation pump (25); the second circulation pump (17) is connected to the second circulation pump (26); the second circulation pump (18) is connected to the second circulation pump (27); the second circulation pump (19) is connected to the second circulation pump (28); the second circulation pump (19) is connected to the second circulation pump (29); the second circulation pump (21) is connected to the second circulation pump (29); the second circulation pump (21) is connected to the second circulation pump (29); the second circulation pump ( The first circulating pump (4) is used to realize the continuous circulation of liquid-phase reaction materials in the device to participate in the reaction; the upper part of the reactor (3) is connected to a condenser (7), and the outlet of the condenser (7) is provided with an oil-water separator (8) for use in conjunction with the condenser. The mist of gas-phase reaction materials generated in the upper space of the reactor (3) is sent to the condenser (7) for condensation through the second circulating pump (6). After the condensate is separated by the oil-water separator (8), the oil-phase product flows back to the reactor (3) to continue to participate in the reaction, and the aqueous waste liquid is sent out of the reaction system.

2. The device for preparing medium and long chain alkyl naphthalene according to claim 1, characterized in that: The bottom of the spray nozzle (2) is a porous structure with uniform distribution and close arrangement. During the reaction process, the liquid phase material is dispersed and sprayed into the reaction kettle (3) through the spray nozzle (2).

3. The preparation device for medium and long chain alkyl naphthalene according to claim 2, characterized in that: The hole structure at the bottom of the spray nozzle (2) is a circular hole structure with a hole diameter of 0.1 to 2 mm.

4. The device for preparing medium and long chain alkyl naphthalene according to claim 1, characterized in that: The lower end of the oil-water separator (8) is a conical structure.

5. The device for preparing medium- and long-chain alkylnaphthalene according to any one of claims 1 to 4, characterized in that: The reactor (3), the first circulation pump (4) and the heat exchanger (5) form a first circulation system; the reactor (3), the second circulation pump (6), the condenser (7) and the oil-water separator (8) form a second circulation system; during the reaction process, the first circulation system and the second circulation system work independently or simultaneously.

6. A method for preparing a medium-chain alkyl naphthalene, wherein the molecular structure of the medium-chain alkyl naphthalene product is as follows: in, R is an alkyl group having 10 to 20 carbon atoms; characterized in that the preparation method comprises the following steps using the preparation device for medium- and long-chain alkylnaphthalene according to any one of claims 1 to 5: S1, a step of preparing an ionic liquid catalyst in a catalyst tank (1); S2, the step of preparing alkyl naphthalene by Friedel-Crafts reaction in a reaction vessel (3) using an ionic liquid catalyst; and S3, the step of separating the product to obtain a high-purity alkyl naphthalene product.

7. The method for preparing medium- and long-chain alkylnaphthalene according to claim 6, characterized in that: Step S1 specifically comprises: filling the catalyst tank (1) with nitrogen, then placing anhydrous aluminum chloride and triethylamine hydrochloride in a molar ratio of 2.0:1 to 3.0:1 in the catalyst tank (1), reacting for 4 hours under the conditions of a pressure of 0.01 MPa in the reaction system and a reaction temperature of 80° C., to obtain a fresh ionic liquid catalyst.

8. The method for preparing medium- and long-chain alkylnaphthalene according to claim 6, characterized in that: Step S2 specifically comprises: filling the reactor (3) with nitrogen, then adding the ionic liquid catalyst into the reactor (3), and then adding the reaction materials naphthalene, fatty alcohol, and an appropriate amount of organic solvent in sequence according to a molar ratio of 1:1.20 to 1:1.25, reacting at a reaction temperature of 60°C for 1 to 2 hours to obtain a reaction product whose main component is alkylnaphthalene.

9. The method for preparing medium- and long-chain alkylnaphthalene according to claim 6, characterized in that: Step S3 specifically comprises: extracting the reaction product obtained in S2 with an extractant to remove the aqueous phase, and then rotary evaporating to remove the solvent, the extractant and the residual fatty alcohol to obtain a high-purity alkylnaphthalene product; the extractant is dichloromethane.

10. A method for preparing a medium-chain alkyl naphthalene, wherein the molecular structure of the medium-chain alkyl naphthalene product is as follows: in, R is an alkyl group having 10 to 20 carbon atoms; the device for preparing alkylnaphthalene according to any one of claims 1 to 5 is characterized in that it comprises the following steps: S1, opening the nitrogen valve of the catalyst tank (1), replacing the catalyst tank (1) with nitrogen, and maintaining the pressure in the catalyst tank (1) at 0.01 MPa, then adding anhydrous aluminum chloride and triethylamine hydrochloride into the catalyst tank for reaction to obtain an ionic liquid catalyst; wherein the molar ratio of anhydrous aluminum chloride to triethylamine hydrochloride is 2.0:1 to 3.0:1, the reaction temperature is 80°C, and the reaction time is 4 hours; S2, open the nitrogen valve of the reactor (3), replace the nitrogen in the reactor (3), and maintain the pressure in the reactor at 0.01MPa, then add the ionic liquid catalyst prepared in step S1 into the reactor (3), then add naphthalene, fatty alcohol and solvent, start the first circulation pump (4), and pump the liquid phase material composed of naphthalene, fatty alcohol, solvent and ionic liquid catalyst from the bottom of the reactor (3) through the first circulation pump (4) to enter the heat exchanger (5), so that the liquid phase material is heated to a reaction temperature of 60 to 80° C., and then dispersedly sprayed into the reactor (3) through the spray nozzle (2). ) to react, the gaseous material mist generated in the reactor (3) is pumped out by the second circulation pump (6) and sent to the condenser (7) for condensation, and the condensate is sent to the oil-water separator (8) for water-oil separation, the temperature of the oil-water separator is controlled at 10-20°C, the upper oil phase is refluxed to the reactor (3) as the reaction material to continue to participate in the reaction, and the lower water phase is sent out of the reaction system as waste liquid; wherein the molar ratio of the reaction materials naphthalene and fatty alcohol is 1:1.20-1:1.25, the molar ratio of the ionic liquid catalyst to naphthalene is 8:1-12:1, the reaction temperature is 60°C, and the reaction time is 1-2h. S3. After the reaction is completed, the reaction product obtained in the reactor is extracted with an extractant to remove the aqueous phase, and then the solvent, the extractant and the residual fatty alcohol are removed by rotary evaporation to obtain a high-purity alkylnaphthalene product; wherein the extractant is dichloromethane.

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