Method and apparatus for preparing flanger carboxylic acid

Abstract

This application discloses a method and apparatus for preparing frangic acid, more specifically, the method using 5-hydroxymethylfurfural as a raw material, water as the reaction solvent, and alkali to obtain a mixed reaction solution, a fixed bed as the reactor, and different proportions of polymetallic La x Co y MnV z The method involves using a catalyst to pass an aqueous solution containing frangic acid salt through a catalyst bed at a constant temperature, constant oxygen pressure, and constant feed rate, then acidifying the solution to precipitate frangic acid, and finally filtering to obtain a solid product. This method has a high yield of the product, a simple process pathway, and potential industrial applications.

Description

[Technical Field]

[0001] The present invention belongs to the technical field of the synthesis of frangic acid compounds, and more particularly to a method and apparatus for preparing frangic acid compounds. [Background technology]

[0002] 2,5-Franzicarboxylic acid (FDCA) is one of 12 important platform molecules designated by the U.S. Department of Energy. Its most important use is as a polymerization monomer for preparing polyesters, polyamides, and polyurethanes. Polyesters formed from FDCA have a high potential to replace polyesters such as PET and PBT, and offer advantages such as biodegradability and environmental protection. Simultaneously, FDCA has important applications as a key raw material in fields such as pharmaceuticals, agrochemicals, fire protection, and plasticizers.

[0003] 5-Hydroxymethylfurfural (abbreviated as HMF) can be oxidized to several important compounds, such as maleic anhydride, frangicarboaldehyde, and frangic carboxylic acid. Currently, much research is being conducted on methods for preparing frangic carboxylic acid from HMF, and this catalytic oxidation process is typically achieved using precious metal-based catalysts. Platinum, palladium, gold, and ruthenium have been reported as precious metals with good catalytic efficiency. Considering the cost of catalysts, developing inexpensive metal catalyst systems for the conversion of HMF to FDCA would be of greater industrial value.

[0004] Given the important functions and applications of 2,5-franzicarboxylic acid, research into oxidizing HMF to FDCA using inexpensive metal catalyst systems is of great significance. However, problems remain in the preparation process, such as strict reaction conditions, high catalyst costs, a complex and uncontrollable catalyst preparation process, and disadvantages for large-scale industrial production. [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] In view of this, the present invention provides a method and apparatus for preparing flangic acid in order to solve the above technical problems. The preparation method according to the present invention uses inexpensive catalysts and raw materials, significantly reduces reaction costs, has a simple process, is economical and environmentally friendly, and is suitable for large-scale industrial production. [Means for solving the problem]

[0006] To achieve the above technical objectives and technical effects, the present invention is realized by the following technical means.

[0007] An embodiment of the first aspect of the present invention provides a method for preparing a flanger carboxylic acid, the preparation method being:

[0008] The process includes the steps of using 5-hydroxymethylfurfural as a raw material, water as the reaction solvent, dissolving 5-hydroxymethylfurfural and alkali in water to obtain a 5-hydroxymethylfurfural mixed reaction solution, using a fixed-bed reactor, using a polymetallic catalyst, filling the bed of the fixed-bed reactor with the catalyst, starting the fixed-bed reactor, setting the reaction temperature and pressure of the fixed-bed reactor, introducing gas into the fixed-bed reactor and pumping pure water into the fixed-bed reactor, pumping the 5-hydroxymethylfurfural mixed reaction solution into the fixed-bed reactor after the reaction temperature and pressure in the fixed-bed reactor reach the set values, passing the 5-hydroxymethylfurfural mixed reaction solution first through the bed of the fixed-bed reactor filled with catalyst to obtain an aqueous solution containing frangic acid salt, then acidifying the solution to precipitate a solid substance, and finally filtering the solid substance to obtain frangic acid.

[0009] The catalyst is La x Co y MnV z It is a polymetallic catalyst, as indicated by the label.

[0010] In polymetallic catalysts, the molar ratio of V / Mn is 1 to 0.5, the molar ratio of Co / Mn is 1 to 0.5, and the molar ratio of La / Mn is 0.05, 0.1, 0.15, or 0.2.

[0011] The alkali is a mixture of one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate in any ratio, and preferably the alkali is at least one of sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate.

[0012] In one embodiment, the mass concentration of 5-hydroxymethylfurfural in the 5-hydroxymethylfurfural mixed reaction solution is 1-10%.

[0013] The molar ratio of the alkali to 5-hydroxymethylfurfural is 4:1 to 2:1, preferably 3:1 to 2:1.

[0014] In one embodiment, the process for preparing the polymetallic catalyst is:

[0015] Step S1 involves dissolving a manganese source, a vanadium source, a cobalt source, and a lanthanum source in ethanol and then ultrasonically dissolving them to prepare solution A.

[0016] Step S2 involves dissolving citric acid in ethanol and then ultrasonically dissolving it to prepare solution B.

[0017] Step S3 includes vigorously stirring solution B, in which solution A is injected into solution B during the vigorous stirring process, stirring until it becomes a viscous gel, leaving it at room temperature for 24 hours, drying it in a vacuum dryer at 60°C until it reaches a constant weight, then removing it and grinding it into a powder to obtain a polymetallic catalyst precursor, transferring the polymetallic catalyst to a muffle furnace, calcining it at 400°C for 5 hours, and further cooling, tableting and sieving to obtain a polymetallic catalyst.

[0018] In one embodiment, in step S1, the manganese source is a mixture of one or more of manganese acetate and manganese chloride in any ratio.

[0019] In step S1, the vanadium source is a mixture of one or more of sodium vanadate and vanadylacetylacetonate in any ratio.

[0020] In step S1, the cobalt source is a mixture of one or more of cobalt nitrate and cobalt acetate in any ratio.

[0021] In step S1, the lanthanum source is a mixture of one or more of lanthanum nitrate and lanthanum acetate in any ratio.

[0022] In step S1, the molar ratio of vanadium elements in the vanadium source to manganese elements in the manganese source is (0.5~1):1.

[0023] In step S1, the molar ratio of cobalt elements in the cobalt source to manganese elements in the manganese source is (0.5~1):1.

[0024] In step S1, the molar ratio of lanthanum in the lanthanum source to manganese in the manganese source is selected from 0.05:1, 0.1:1, 0.15:1, or 0.2:1.

[0025] In step S3, the molar ratio of manganese in the manganese source, vanadium in the vanadium source, cobalt in the cobalt source, and lanthanum in the lanthanum source in solution A, and citric acid in solution B, is (Mn+V+Co+La):citric acid = 1:1.5.

[0026] In one embodiment, the size of the polymetallic catalyst is 10 to 300 mesh, preferably 30 to 200 mesh.

[0027] In one embodiment, when the catalyst is packed into the bed of a fixed-bed reactor, the amount of catalyst packed is 100%.

[0028] In one embodiment, the set value for the reaction temperature is 120 to 160°C, and the set value for the reaction pressure is 0.5 to 4 MPa, preferably the set value for the reaction temperature is 120 to 140°C, and the set value for the reaction pressure is 2 to 3 MPa.

[0029] The aforementioned gas is air or oxygen gas.

[0030] In one embodiment, during the process of pumping the 5-hydroxymethylfurfural mixed reaction solution into a fixed-bed reactor, the flow rate of the 5-hydroxymethylfurfural mixed reaction solution is 2 to 20 mL / min, preferably 2 to 10 mL / min.

[0031] In one embodiment, the specific acidification process involves adding an acidifying reagent to the collected aqueous solution containing frangic acid salt, and acidifying the solution until the pH of the frangic acid salt-containing aqueous solution becomes less than 1, causing a solid to precipitate. The acidifying reagent is a mixture of one or more of hydrochloric acid, sulfuric acid, and nitric acid in any ratio, and preferably the acidifying reagent is hydrochloric acid.

[0032] An embodiment of a second aspect of the present invention provides a preparation apparatus for a method of preparing a flanger carboxylic acid, the preparation apparatus comprising a supply system, a reaction system and a product processing system, wherein the supply end and discharge end of the reaction system are in communication with the supply system and the product processing system, respectively.

[0033] The supply system includes a gas source and a metering pump.

[0034] The reaction system includes a fixed-bed reactor and a reactor chamber that are in communication with each other, and the gas discharge end of the gas source and the discharge end of the metering pump are both in communication with the fixed-bed reactor.

[0035] The product processing system includes a cooler, a gas-liquid separator, and a storage tank.

[0036] The gas source includes a nitrogen gas source and an oxygen gas / air source, and the gas discharge ends of both the nitrogen gas source and the oxygen gas / air source are connected to a fixed-bed reactor via a gas discharge pipeline, and there are two gas mass flow controllers, each of which is attached to a gas discharge pipeline.

[0037] The supply end of the metering pump is connected to a supply tank, a balance is provided at the bottom of the supply tank, a preheater is provided outside the discharge end of the metering pump, and a preheating furnace is provided outside the preheater.

[0038] A heat-insulating jacket is provided at one end of the discharge end of the metering pump that is close to the fixed-bed reactor on the outside, and the heat-insulating jacket is located between the preheater and the fixed-bed reactor.

[0039] The aforementioned gas discharge pipeline passes through the preheater and the heat-insulating jacket in sequence and communicates with the fixed-bed reactor.

[0040] A discharge pipeline is provided at the discharge port of the reactor chamber, the discharge end of the fixed-bed reactor is connected to the discharge pipeline, the discharge pipeline passes through the cooler and is connected to a gas-liquid separator, and the discharge end of the gas-liquid separator is connected to a storage tank.

[0041] A sampling valve is further provided in the gas-liquid separator. [Effects of the Invention]

[0042] Compared to the conventional technology, the beneficial effects of the present invention are as follows:

[0043] 1. According to the present invention, 5-hydroxymethylfurfural and an alkali are dissolved in water to obtain a 5-hydroxymethylfurfural mixed reaction solution. Using a fixed bed as a reactor and multi-metal La x Co y MnV z as a catalyst, reacting at a certain temperature, a certain oxygen pressure, and a certain flow rate to obtain an aqueous solution of furandicarboxylate, acidifying to precipitate furandicarboxylic acid, and filtering to obtain a solid product. This method is convenient for product separation, has a simple process, and has potential application value.

[0044] 2. In the preparation apparatus for the method for preparing furandicarboxylic acid according to the present invention, the supply tank can store liquid reaction raw materials, the metering pump can realize continuous supply of the 5-hydroxymethylfurfural mixed reaction solution, the preheater can preheat and mix the 5-hydroxymethylfurfural mixed reaction solution, the fixed bed reactor can be filled with a catalyst, and functions as the place where the oxidation reaction takes place. The reactor chamber can provide a constant temperature heat exchange medium to the reactor heat exchange jacket, the cooler can realize the cooling and condensation of the aqueous solution containing furandicarboxylate, the gas-liquid separator can realize the separation of gas-liquid products according to the boiling point of the material, and the above-mentioned liquid storage tank can collect liquid reaction products.

[0045] 3. In the present invention, FDCA prepared by catalyzing 5-HMF with the La x Co y MnV z catalyst has high catalytic activity and selectivity. Due to the presence of V in the multi-metal catalyst, Mn generates many oxygen vacancies and generates many active species. The presence of La promotes the interaction between Mn and V, and at the same time, the introduction of Co further improves the oxidation ability of the catalyst.

Brief Description of the Drawings

[0046] The drawings described herein are provided for a further understanding of the present invention and constitute part of this application; the exemplary embodiments and descriptions thereof are for illustrative purposes only and do not unduly limit the present invention. [Figure 1] This is a schematic diagram of a preparation apparatus for a method of preparing flanger carboxylic acid according to one embodiment of the present invention. [Figure 2] This is an XPS image of the La0.05CoMnV catalyst, showing that the prepared polymetallic catalyst La0.05CoMnV contains the elements La, Co, Mn, and V. [Figure 3] These are XRD charts of the polymetallic catalysts La0.05CoMnV, La0.1CoMnV, and La0.15CoMnV. [Figure 4] This is a Fourier transform infrared (FTIR) spectral analysis diagram of the polymetallic catalyst La0.05CoMnV. [Figure 5] This is a Fourier transform infrared (FTIR) spectral analysis diagram of the polymetallic catalyst La0.1CoMnV. [Figure 6] This is a Fourier transform infrared (FTIR) spectral analysis diagram of the polymetallic catalyst La0.15CoMnV. [Figure 7] This is the Raman spectrum diagram of the polymetallic catalyst La0.05CoMnV. [Figure 8] This is a BET chart for the polymetallic catalyst La0.15CoMnV. [Modes for carrying out the invention]

[0047] The technical means in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiments of the present invention, but obviously the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments that can be obtained based on the embodiments of the present invention without creative work by a person skilled in the art are all within the scope of protection of the present invention.

[0048] In the description of this invention, terms such as "opening," "top," "bottom," "thickness," "top," "middle," "length," "inside," and "perimeter" indicate orientation or positional relationships and are merely for the convenience and simplification of the description of this invention. They do not indicate or suggest that the parts or elements mentioned have a specific orientation or must be configured and operated in a specific orientation, and therefore should not be understood as limiting this application.

[0049] An embodiment of the first aspect of the present invention provides a method for preparing a flanger carboxylic acid, the preparation method comprising the following steps.

[0050] S1: Using 5-hydroxymethylfurfural as a raw material and water as the reaction solvent, 5-hydroxymethylfurfural and alkali are dissolved in water to obtain a 5-hydroxymethylfurfural mixed reaction solution.

[0051] In the 5-hydroxymethylfurfural mixed reaction solution, the mass concentration of 5-hydroxymethylfurfural is 1-10%.

[0052] Alkali are mixtures of one or more of the following in any proportion: sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate.

[0053] The molar ratio of alkali to 5-hydroxymethylfurfural is 4:1 to 2:1.

[0054] S2: Using a fixed-bed reactor as the reaction vessel, polymetallic La x Co y MnV z The catalyst is used, and the catalyst is packed into the bed of the fixed-bed reactor. Here, the amount of catalyst packed is 100%.

[0055] In polymetallic catalysts, the molar ratio of V / Mn is 1 to 0.5, the molar ratio of Co / Mn is 1 to 0.5, and the molar ratio of La / Mn is 0.05, 0.1, 0.15, or 0.2.

[0056] The preparation process for the polymetallic catalyst is as follows:

[0057] S21: Dissolve the manganese source, vanadium source, cobalt source, and lanthanum source in ethanol and sonicate dissolve to prepare solution A. The manganese source is a mixture of one or more of manganese acetate and manganese chloride in any ratio; the vanadium source is a mixture of one or more of sodium vanadate and vanadylacetylacetonate in any ratio; the cobalt source is a mixture of one or more of cobalt nitrate and cobalt acetate in any ratio; and the lanthanum source is a mixture of one or more of lanthanum nitrate and lanthanum acetate in any ratio.

[0058] In step S1, the molar ratio of vanadium elements in the vanadium source to manganese elements in the manganese source is (0.5~1):1.

[0059] The molar ratio of cobalt elements in the above cobalt source to manganese elements in the manganese source is (0.5~1):1.

[0060] The molar ratio of lanthanum in the lanthanum source to manganese in the manganese source is selected from 0.05:1, 0.1:1, 0.15:1, or 0.2:1.

[0061] S22: Dissolve citric acid in ethanol and prepare solution B by ultrasonic dissolution.

[0062] S23: Solution B is vigorously stirred, and during the vigorous stirring process, solution A is injected into solution B and stirred until it becomes a viscous gel. Then it is left at room temperature for 24 hours, dried in a vacuum dryer at 60°C until a constant weight is reached, then removed and pulverized into a powder to obtain a polymetallic catalyst precursor. The polymetallic catalyst is transferred to a muffle furnace and calcined at 400°C for 5 hours. Further cooling, tableting, and sieving are performed to obtain the polymetallic catalyst. The size of the prepared polymetallic catalyst is 10 to 300 mesh, preferably 30 to 200 mesh.

[0063] In step S3, the molar ratio of manganese in the manganese source, vanadium in the vanadium source, cobalt in the cobalt source, and lanthanum in the lanthanum source in solution A, and citric acid in solution B, is (Mn+V+Co+La):citric acid = 1:1.5.

[0064] S3: The fixed-bed reactor is started, the reaction temperature inside the fixed-bed reactor is set to 120-160°C and the reaction pressure to 0.5-4 MPa, air or oxygen gas is introduced into the fixed-bed reactor, and pure water is pumped into the fixed-bed reactor. After the reaction temperature and pressure inside the fixed-bed reactor reach the set values, the 5-hydroxymethylfurfural mixed reaction solution is pumped into the fixed-bed reactor at a flow rate of 2-20 mL / min, and the 5-hydroxymethylfurfural mixed reaction solution is first passed through the bed of the fixed-bed reactor, which is filled with catalyst, to obtain an aqueous solution containing frangic acid salt.

[0065] S4: An aqueous solution containing frangic acid salt is acidified to precipitate a solid substance, and finally the solid substance is filtered to obtain frangic acid. The specific acidification process involves adding an acidifying reagent to the collected aqueous solution containing frangic acid salt and acidifying it until the pH of the aqueous solution containing frangic acid salt becomes less than 1, at which point a solid precipitates.

[0066] The acidification reagent is a mixture of one or more of hydrochloric acid, sulfuric acid, and nitric acid in any proportion.

[0067] As shown in Figure 2, an embodiment of a second aspect of the present invention provides a preparation apparatus for a method of preparing flanger carboxylic acid, the preparation apparatus comprising a supply system, a reaction system and a product processing system, wherein the supply end and discharge end of the reaction system are in communication with the supply system and the product processing system, respectively.

[0068] The supply system includes a gas source and a metering pump.

[0069] The reaction system includes a fixed-bed reactor and a reactor chamber that are in communication with each other, and the gas discharge end of the gas source and the discharge end of the metering pump are both in communication with the fixed-bed reactor.

[0070] The product processing system includes a cooler, a gas-liquid separator, and a storage tank.

[0071] The gas sources include a nitrogen gas source and an oxygen gas / air source, and the gas discharge ends of both the nitrogen gas source and the oxygen gas / air source are connected to the fixed-bed reactor via gas discharge pipelines. There are two gas mass flow controllers, and each of the two gas mass flow controllers is attached to a gas discharge pipeline.

[0072] The supply end of the metering pump is connected to the supply tank, a balance is provided at the bottom of the supply tank, a preheater is provided outside the discharge end of the metering pump, and a preheating furnace is provided outside the preheater.

[0073] A thermal insulation jacket is provided at one end of the discharge end of the metering pump that is close to the fixed-bed reactor on the outside, and the thermal insulation jacket is located between the preheater and the fixed-bed reactor.

[0074] The gas discharge pipeline passes through the preheater and the thermal insulation jacket in sequence and communicates with the fixed-bed reactor. A discharge pipeline is provided at the outlet of the reactor chamber, the discharge end of the fixed-bed reactor is connected to the discharge pipeline, the discharge pipeline passes through the cooler and is connected to the gas-liquid separator, and the discharge end of the gas-liquid separator is connected to the liquid storage tank. A sampling valve is further provided in the gas-liquid separator.

[0075] The specific process for preparing frangic acid in the preparation apparatus involves adding the prepared 5-hydroxymethylfurfural mixed reaction solution to a supply tank, preheating it in a preheater, then transporting it to a fixed-bed reactor at a constant flow rate using a metering pump for heating, cooling the product obtained after the reaction in a condenser, separating it in a gas-liquid separator, collecting it in a storage tank to obtain the reaction solution, discharging it with a sampling valve to obtain an aqueous solution containing frangic acid salt, further acidifying the aqueous solution containing frangic acid salt to precipitate solid material, and finally filtering the solid material to obtain frangic acid.

[0076] The following are specific examples, and unless otherwise specified, all reagents used in the examples of the present invention are commercially available.

[0077] Example 1 This embodiment provides a method for preparing a polymetallic catalyst, and the specific preparation process is as follows.

[0078] Preparation of Solution A: 0.02 mol manganese acetate (3.46 g), 0.02 mol sodium vanadate (3.68 g), 0.02 mol cobalt nitrate hexahydrate (5.82 g), and 0.001 mol lanthanum nitrate (0.33 g) were ultrasonically dissolved in 200 mL of ethanol.

[0079] Preparation of Solution B: Citric acid (the molar ratio of manganese source, vanadium source, cobalt source, and lanthanum source in Solution A to citric acid in Solution B is (Mn+V+Co+La):citric acid = 1.5:1, i.e., 0.0915 mol, 17.56 g of citric acid) was ultrasonically dissolved in 200 mL of ethanol.

[0080] Preparation of polymetallic catalyst: Quickly add solution A to solution B while stirring vigorously, stir until it becomes a viscous gel, then let it stand at room temperature for 24 hours to react and mature thoroughly, then dry in a vacuum dryer at 60°C until the mass is constant, remove and grind into a powder to obtain a polymetallic catalyst precursor, transfer the polymetallic catalyst precursor to a muffle furnace, heat in air from 30°C to 400°C and maintain the temperature for 5 hours to calcinate, heating at a rate of 2°C / min, and finally the polymetallic catalyst La 0.05 CoMnV is obtained, and then after tableting and sieving, La with different mesh numbers is obtained. 0.05 A polymetallic catalyst denoted as CoMnV was obtained.

[0081] The polymetallic catalysts prepared in this embodiment are specifically shown in Table 1.

[0082] Example 2 This example provides the preparation of a polymetallic catalyst, the specific preparation process of which is the same as in Example 1, the difference being that the amount of lanthanum nitrate used is 0.66 g (0.002 mol), the amount of citric acid used is 17.86 g, and the prepared polymetallic catalyst is La 0.1 It is abbreviated as MnCoV.

[0083] The polymetallic catalysts prepared in this embodiment are specifically shown in Table 1.

[0084] Example 3 This example provides the preparation of a polymetallic catalyst, the specific preparation process being the same as in Example 1, the difference being that the amount of cobalt nitrate hexahydrate used is 2.91 g (0.01 mol), the amount of citric acid used is 14.69 g, and the prepared polymetallic catalyst is La 0.05 Co 0.5 It is written as MnV.

[0085] The polymetallic catalysts prepared in this embodiment are specifically shown in Table 1. Example 4 This example provides the preparation of a polymetallic catalyst. The specific preparation process is the same as in Example 1, with the difference being that the amount of cobalt nitrate hexahydrate used is 2.91 g (0.01 mol), the amount of sodium vanadate used is 1.84 g, and the amount of citric acid used is 11.8 g. The prepared polymetallic catalyst is La 0.05 Co 0.5 MnV 0.5 This is how it is written.

[0086] The polymetallic catalysts prepared in this embodiment are specifically shown in Table 1.

[0087] Example 5 This example provides the preparation of a polymetallic catalyst, the specific preparation process of which is the same as in Example 1, the difference being that the amount of lanthanum nitrate used is 0.99 g (0.003 mol), the amount of citric acid used is 18.16 g, and the prepared polymetallic catalyst is La 0.15 It is written as CoMnV.

[0088] The polymetallic catalysts prepared in this embodiment are specifically shown in Table 1.

[0089] Example 6 This example provides the preparation of a polymetallic catalyst. The specific preparation process is the same as in Example 1, with the difference being that the amount of lanthanum nitrate used is 1.32 g (0.004 mol), the amount of cobalt nitrate used is 1.83 g (0.01 mol), and the amount of citric acid used is 15.56 g. The prepared polymetallic catalyst is La 0.2 Co 0.5 It is written as MnV.

[0090] The polymetallic catalysts prepared in this embodiment are specifically shown in Table 1.

[0091] Example 7 This example provides the preparation of a polymetallic catalyst, the specific preparation process of which is the same as in Example 1, the difference being that the amount of lanthanum nitrate used is 0.66 g (0.002 mol), the amount of cobalt nitrate used is 1.83 g (0.01 mol), and the amount of citric acid used is 14.99 g, and the prepared polymetallic catalyst is La 0.1 Co 0.5 It is written as MnV.

[0092] The polymetallic catalysts prepared in this embodiment are specifically shown in Table 1.

[0093] Example 8 This example provides the preparation of a polymetallic catalyst, the specific preparation process of which is the same as in Example 1, the difference being that the amount of lanthanum nitrate used is 1.32 g (0.004 mol), the amount of citric acid used is 18.44 g, and the prepared polymetallic catalyst is La 0.2 It is written as CoMnV.

[0094] The polymetallic catalysts prepared in this embodiment are specifically shown in Table 1.

[0095] Example 9 This example provides the preparation of a polymetallic catalyst. The specific preparation process is the same as in Example 1, with the difference being that the amount of cobalt nitrate hexahydrate used is 4.37 g (0.015 mol), the amount of sodium vanadate used is 2.76 g (0.015 mol), and the amount of citric acid used is 14.70 g. The prepared polymetallic catalyst is La 0.05 Co 0.75 MnV 0.75 This is how it is written.

[0096] The polymetallic catalysts prepared in this embodiment are specifically shown in Table 1.

[0097] [Table 1]

[0098] Experimental Example 1 The polymetallic catalyst La prepared in Example 1 0.05 CoMnV, the polymetallic catalyst La prepared in Example 2 0.1 CoMnV, the polymetallic catalyst La prepared in Example 5 0.15 Performance tests were conducted on CoMnV.

[0099] Polymetallic catalyst La 0.05 CoMnV, polymetallic catalyst La 0.1 CoMnV and polymetallic catalyst La 0.15 The XPS spectrum of CoMnV is shown in Figure 2A, which shows the composition of the prepared polymetallic catalyst, namely, the polymetallic catalyst contains the elements La, Co, Mn, and V. Figures 2B, 2C, 2D, 2E, and 2F show characteristic photoelectron spectra of La, Co, Mn, O, and V, respectively, demonstrating the presence of La, Co, Mn, and V in the prepared polymetallic catalyst.

[0100] Polymetallic catalyst La 0.05 CoMnV, polymetallic catalyst La 0.1 CoMnV and polymetallic catalyst La 0.15 Refer to Figure 3 for the XRD chart of CoMnV. As can be seen from Figure 3, even when the amount of La changes, the XRD diffraction peak does not clearly change, and at the same time, it is attributed to Mn, Co, and V, forming a spinel phase, which is favorable for the change in the active valence of the catalyst during the oxidation process. The absence of a clear peak derived from the La species indicates the high dispersibility of La, and the presence of La promotes the interaction between Mn and V, while the introduction of Co further improves the oxidation capacity of the catalyst.

[0101] La 0.05 For the infrared spectral diagram of the MnCoV catalyst, see Figure 4. 0.1 For the infrared spectral diagram of the MnCoV catalyst, see Figure 5. 0.15 Refer to Figure 6 for the infrared spectral diagram of the MnCoV catalyst. Infrared characteristic analysis revealed that the structural properties of the catalyst did not change significantly even when the ratio of La was varied.

[0102] Polymetallic catalyst La 0.05See Figure 7 for the Raman spectrum of CoMnV, which is from 500 to 900 cm⁻¹. -1 CoMnVO x A stretching vibration exists in the tetrahedral structure, ranging from 200 to 500 cm. -1 This demonstrates the existence of tetrahedral bending vibrations within the specified range. 200cm -1 In the region below 622 cm², the motion is that of rigid bodies of Mn-O polyhedra and VO4 tetrahedra. -1 The peak at 242 cm² is attributed to the symmetric stretching vibration peak of the (Co / Mn)O6 octahedron. -1 The peak at 900 cm² is the antisymmetric stretching vibration peak of the (Co / Mn)O6 octahedron. -1 The above Raman peaks are thought to be due to harmonics caused by grid distortion and expansion / contraction.

[0103] Polymetallic catalyst La 0.15 For the CoMnV BET chart, see Figure 8, and the surface area of ​​the catalyst is 12.8 m². 2 The concentration is 25.43117 nm, and the average adsorption pore size is 25.43117 nm. As can be seen from the BET chart results, the catalyst exhibits a clear mesoporous structure.

[0104] Based on the above, the prepared La x Co y MnV z Due to the presence of V in the catalyst, Mn generates many oxygen vacancies and produces many active species, the presence of La promotes the interaction between Mn and V, and the introduction of Co further enhances the oxidation capacity of the catalyst. Example 10

[0105] This embodiment provides a method for preparing frangic acid, which includes the following steps.

[0106] 5-hydroxymethylfurfural, i.e., HMF (63 g, 0.5 mol), was dissolved in 2000 g of water, sodium hydroxide (40 g, 1 mol) was added, and the mixture was stirred thoroughly to obtain a 5-hydroxymethylfurfural mixed reaction solution. Here, the molar ratio of sodium hydroxide (alkali) to 5-hydroxymethylfurfural was 2:1. The 100-mesh polymetallic catalyst La prepared in Example 3 was used. 0.05 Co 0.5 MnV was packed into the bed of the fixed-bed reactor (volume 40 mL). The reaction temperature was set to 130°C and the reaction pressure to 2 MPa. The metering pump of the fixed-bed reactor was started, oxygen gas was introduced into the reactor, and pure water was pumped at a rate of 20 mL / min. After the reaction parameters reached the set values, the 5-hydroxymethylfurfural mixed reaction solution was pumped at a rate of 2 mL / min. After the reaction was complete, the reaction solution was collected, sampled, and detected. The detection conditions were as follows: Hitachi L2000 HPLC system, Alltech C18 column, mobile phase methanol: 0.5 wt% trifluoroacetic acid aqueous solution: 20:80, flow rate: 1.0 mL / min, column temperature: 30°C, detector: DAD, detection wavelength: 264 nm. The purity of frangic acid (FDCA) was measured to be 99.3%. The collected reaction mixture was acidified to pH < 1 by adding hydrochloric acid, then the solid was precipitated, filtered, and dried to obtain FDCA in 84% yield.

[0107] The purity and yield of the prepared FDCA are specifically shown in Table 2.

[0108] Example 11 This example provides a method for preparing frangic acid, which differs from Example 10 in that the mass of water is 1157 g, i.e., the mass concentration of HMF is changed to 5%, while the other operating steps are the same as in Example 10.

[0109] According to the test results, FDCA had a yield of 76% and a purity of 98.3%.

[0110] The purity and yield of the prepared FDCA are specifically shown in Table 2. Example 12

[0111] This example provides a method for preparing frangic acid, which differs from Example 10 in that the mass of sodium hydroxide is 80 g (2.0 mol), i.e., the molar ratio of alkali to 5-hydroxymethylfurfural is 4:1, while the other operating steps are the same as in Example 10.

[0112] According to the test results, FDCA had a yield of 81% and a purity of 99.0%.

[0113] The purity and yield of the prepared FDCA are specifically shown in Table 2.

[0114] Example 13 This example provides a method for preparing frangic acid, and differs from Example 10 in that the mass of water is 684.5 g, i.e., the mass concentration of HMF is changed to 8%, while the other operating steps are the same as in Example 10.

[0115] According to the test results, FDCA had a yield of 75% and a purity of 98.8%.

[0116] The purity and yield of the prepared FDCA are specifically shown in Table 2.

[0117] Example 14 This example provides a method for preparing frangic acid, which differs from Example 10 in that the mass of water is 527 g, i.e., the mass concentration of 5-hydroxymethylfurfural is 10%, while the other operating steps are the same as in Example 10.

[0118] According to the test results, FDCA had a yield of 72% and a purity of 98.2%.

[0119] The purity and yield of the prepared FDCA are specifically shown in Table 2.

[0120] Example 15 This example provides a method for preparing frangic acid, which differs from Example 10 in that the amount of water added is 6197 g, meaning that the mass concentration of 5-hydroxymethylfurfural in the 5-hydroxymethylfurfural mixed reaction solution is 1%, while the other operating steps are the same as in Example 10.

[0121] According to the test results, FDCA had a yield of 70% and a purity of 99.8%.

[0122] The purity and yield of the prepared FDCA are specifically shown in Table 2.

[0123] Example 16 This example provides a method for preparing frangic acid, which differs from Example 10 in that the mass of sodium hydroxide is 60 g (1.5 mol), i.e., the molar ratio of alkali to 5-hydroxymethylfurfural is 3:1, while the other operating steps are the same as in Example 10.

[0124] According to the test results, FDCA had a yield of 80% and a purity of 99.6%.

[0125] The purity and yield of the prepared FDCA are specifically shown in Table 2.

[0126] [Table 2]

[0127] Example 17 This embodiment provides a method for preparing flanger carboxylic acid, wherein a 100-mesh polymetallic catalyst La 0.05 Co 0.5 This example differs from Example 10 in that the MnV is changed to 200 mesh, but the other operating steps are the same as in Example 10.

[0128] According to the test results, FDCA had a yield of 91% and a purity of 99.4%.

[0129] The purity and yield of the prepared FDCA are specifically shown in Table 3.

[0130] Example 18 This embodiment provides a method for preparing flanger carboxylic acid, wherein a 100-mesh polymetallic catalyst La 0.05 Co 0.5 This differs from Example 10 in that the MnV is changed to 30 mesh, but the other operating steps are the same as in Example 10.

[0131] According to the test results, FDCA had a yield of 82% and a purity of 98.1%.

[0132] The purity and yield of the prepared FDCA are specifically shown in Table 3.

[0133] Example 19 This embodiment provides a method for preparing flanger carboxylic acid, wherein a 100-mesh polymetallic catalyst La 0.05 Co 0.5 This differs from Example 10 in that the MnV is changed to 50 mesh, but the other operating steps are the same as in Example 10.

[0134] According to the test results, FDCA had a yield of 77% and a purity of 97.6%.

[0135] The purity and yield of the prepared FDCA are specifically shown in Table 3.

[0136] Example 20 This example provides a method for preparing flanger carboxylic acid, and in this example, the polymetallic catalyst La prepared in Example 3 is used. 0.05 Co 0.5 MnV is the polymetallic catalyst La prepared in Example 1 0.05 This example differs from Example 10 in that it is changed to CoMnV, but the other operating steps are the same as in Example 10.

[0137] According to the test results, FDCA had a yield of 79% and a purity of 98.3%.

[0138] The purity and yield of the prepared FDCA are specifically shown in Table 3.

[0139] Example 21 This example provides a method for preparing flanger carboxylic acid, and in this example, the polymetallic catalyst La prepared in Example 3 is used. 0.05 Co 0.5 MnV is the polymetallic catalyst La prepared in Example 4. 0.05 Co 0.5 MnV 0.5 This differs from Example 10 in that it is changed to [specific feature], while the other operating steps are the same as in Example 10.

[0140] According to the test results, FDCA had a yield of 94% and a purity of 99.1%.

[0141] The purity and yield of the prepared FDCA are specifically shown in Table 3.

[0142] Example 22 This example provides a method for preparing flanger carboxylic acid, and in this example, the polymetallic catalyst La prepared in Example 3 is used. 0.05 Co 0.5 MnV is the polymetallic catalyst La prepared in Example 6. 0.2 Co 0.5 This example differs from Example 10 in that it is changed to MnV, but the other operating steps are the same as in Example 10.

[0143] According to the test results, FDCA had a yield of 81% and a purity of 97.9%.

[0144] The purity and yield of the prepared FDCA are specifically shown in Table 3.

[0145] Example 23 This example provides a method for preparing flanger carboxylic acid, and in this example, the polymetallic catalyst La prepared in Example 3 is used. 0.05 Co0.5 MnV is the polymetallic catalyst La prepared in Example 7. 0.1 Co 0.5 This example differs from Example 10 in that it is changed to MnV, but the other operating steps are the same as in Example 10.

[0146] According to the test results, FDCA had a yield of 87% and a purity of 98.8%.

[0147] The purity and yield of the prepared FDCA are specifically shown in Table 3.

[0148] Example 24 This example provides a method for preparing flanger carboxylic acid, and in this example, the polymetallic catalyst La prepared in Example 3 is used. 0.05 Co 0.5 MnV is the polymetallic catalyst La prepared in Example 2. 0.1 This example differs from Example 10 in that it is modified to MnCoV, but the other operating steps are the same as in Example 10.

[0149] According to the test results, FDCA had a yield of 77% and a purity of 99.3%.

[0150] The purity and yield of the prepared FDCA are specifically shown in Table 3.

[0151] Example 25 This example provides a method for preparing flanger carboxylic acid, and in this example, the polymetallic catalyst La prepared in Example 3 is used. 0.05 Co 0.5 MnV is the polymetallic catalyst La prepared in Example 5. 0.15 This example differs from Example 10 in that it is changed to CoMnV, but the other operating steps are the same as in Example 10.

[0152] According to the test results, FDCA had a yield of 75% and a purity of 99.5%.

[0153] The purity and yield of the prepared FDCA are specifically shown in Table 3.

[0154] Example 26 This example provides a method for preparing furan carboxylic acid. In this example, the multi-metal catalyst La 0.05 Co 0.5 MnV prepared in Example 3 is different from Example 10 in that it is changed to the multi-metal catalyst La 0.2 CoMnV prepared in Example 8. Other operation steps are the same as those in Example 10.

[0155] According to the test results, the yield of FDCA was 70% and the purity was 98.6%.

[0156] [[ID=十七]] The purity and yield of the prepared FDCA are specifically shown in Table 3.

[0157] Example 27 This example provides a method for preparing furan carboxylic acid. In this example, the multi-metal catalyst La<0000s88>Co[[ID=二十]] 0.5 MnV prepared in Example 3 is different from Example 10 in that it is changed to the multi-metal catalyst La 0.05 Co 0.75 MnV 0.75 prepared in Example 9. Other operation steps are the same as those in Example 10.

[0158] According to the test results, the yield of FDCA was 69% and the purity was 98.2%.

[0159] The purity and yield of the prepared FDCA are specifically shown in Table 3.

[0160]

Table 3

[0161] Example 28<## This example provides a method for preparing furan carboxylic acid. In this example, it is different from Example 10 in that the reaction temperature of 130 °C is changed to 120 °C. Other operation steps are the same as those in Example 10.

[0162] According to the test results, FDCA had a yield of 76% and a purity of 98.6%.

[0163] The purity and yield of the prepared FDCA are specifically shown in Table 4.

[0164] Example 29 This embodiment provides a method for preparing flanger carboxylic acid, and differs from Example 10 in that the reaction temperature is changed from 130°C to 150°C, while the other operating steps are the same as in Example 10.

[0165] According to the test results, FDCA had a yield of 80% and a purity of 98.4%.

[0166] The purity and yield of the prepared FDCA are specifically shown in Table 4. Example 30

[0167] This embodiment provides a method for preparing flanger carboxylic acid, and differs from Example 10 in that the reaction temperature is changed from 130°C to 160°C, while the other operating steps are the same as in Example 10.

[0168] According to the test results, FDCA had a yield of 72% and a purity of 99.1%.

[0169] The purity and yield of the prepared FDCA are specifically shown in Table 4.

[0170] Example 31 This embodiment provides a method for preparing flanger carboxylic acid, and differs from Example 10 in that oxygen gas is replaced with air, while the other operating steps are the same as in Example 10.

[0171] According to the test results, FDCA had a yield of 74% and a purity of 98.9%.

[0172] The purity and yield of the prepared FDCA are specifically shown in Table 4.

[0173] Example 32 This embodiment provides a method for preparing flanger carboxylic acid, and differs from Example 10 in that the reaction pressure is changed from 2 MPa to 0.5 MPa, while the other operating steps are the same as in Example 10.

[0174] According to the test results, FDCA had a yield of 80% and a purity of 98.6%.

[0175] The purity and yield of the prepared FDCA are specifically shown in Table 4.

[0176] Example 33 This embodiment provides a method for preparing flanger carboxylic acid, and differs from Example 10 in that the reaction pressure is changed from 2 MPa to 3 MPa, while the other operating steps are the same as in Example 10.

[0177] According to the test results, FDCA had a yield of 88% and a purity of 98.8%.

[0178] The purity and yield of the prepared FDCA are specifically shown in Table 4.

[0179] Example 34 This embodiment provides a method for preparing flanger carboxylic acid, and differs from Example 10 in that the reaction pressure is changed from 2 MPa to 4 MPa, while the other operating steps are the same as in Example 10.

[0180] According to the test results, FDCA had a yield of 92% and a purity of 99.5%.

[0181] The purity and yield of the prepared FDCA are specifically shown in Table 4.

[0182] Example 35 This example provides a method for preparing frangic acid, and differs from Example 10 in that the flow rate of the 5-hydroxymethylfurfural reaction mixture is changed from 2 mL / min to 20 mL / min, while the other operating steps are the same as in Example 10.

[0183] According to the test results, FDCA had a yield of 71% and a purity of 97.7%.

[0184] The purity and yield of the prepared FDCA are specifically shown in Table 4.

[0185] Example 36 This example provides a method for preparing frangic acid, and differs from Example 10 in that the flow rate of the 5-hydroxymethylfurfural reaction mixture is changed from 2 mL / min to 10 mL / min, while the other operating steps are the same as in Example 10.

[0186] According to the test results, FDCA had a yield of 78% and a purity of 98.6%.

[0187] The purity and yield of the prepared FDCA are specifically shown in Table 4. Example 37

[0188] This example provides a method for preparing frangic acid, and differs from Example 10 in that the flow rate of the 5-hydroxymethylfurfural reaction mixture is changed from 2 mL / min to 5 mL / min, while the other operating steps are the same as in Example 10.

[0189] According to the test results, FDCA had a yield of 89% and a purity of 99.3%.

[0190] The purity and yield of the prepared FDCA are specifically shown in Table 4.

[0191] [Table 4]

[0192] As can be seen from the above embodiments, La x Co y MnV z The FDCA prepared by catalyzing 5-HMF with the catalyst has high catalytic activity and selectivity. By changing the reaction conditions such as the reaction temperature, reaction pressure, and liquid flow rate, the yield of FDCA can be further improved, and thereby, new ideas and directions for obtaining a higher yield of FDCA are also provided to those skilled in the art.

[0193] According to the present invention, 5-hydroxymethylfurfural and an alkali are dissolved in water to obtain a 5-hydroxymethylfurfural mixed reaction solution. Using a fixed bed as the reactor and a multi-metal La x Co y MnV z as the catalyst, reacting at a certain temperature, a certain oxygen pressure, and a certain flow rate to obtain an aqueous solution of furandicarboxylate, acidifying to precipitate furandicarboxylic acid, and filtering to obtain a solid product. This method is convenient for product separation, the process is simple, and it has potential application value.

[0194] In the description of this specification, the descriptions referring to terms such as "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials, or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. The specific features, structures, materials, or characteristics described can be appropriately combined in any one or more embodiments or examples.

[0195] The basic principle, main features, and advantages of the present invention have been shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and the specification are only for explaining the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention can be variously changed and improved, and all these changes and improvements should be understood to be within the protection scope of the present invention.

Claims

1. The process includes the steps of using 5-hydroxymethylfurfural as a raw material, water as the reaction solvent, dissolving 5-hydroxymethylfurfural and alkali in water to obtain a 5-hydroxymethylfurfural mixed reaction solution, using a fixed-bed reactor, using a catalyst, filling the bed of the fixed-bed reactor with the catalyst, starting the fixed-bed reactor, setting the reaction temperature and pressure of the fixed-bed reactor, introducing gas into the fixed-bed reactor and pumping pure water into the fixed-bed reactor, pumping the 5-hydroxymethylfurfural mixed reaction solution into the fixed-bed reactor after the reaction temperature and pressure in the fixed-bed reactor reach the set values, passing the 5-hydroxymethylfurfural mixed reaction solution first through the bed of the fixed-bed reactor filled with catalyst to obtain an aqueous solution containing frangic acid salt, then acidifying the solution to precipitate a solid substance, and finally filtering the solid substance to obtain frangic acid. The catalyst is La ｘ Co ｙ MnV ｚ It is a polymetallic catalyst, as indicated by the label. In the polymetallic catalyst, the molar ratio of V / Mn is 1 to 0.5, the molar ratio of Co / Mn is 1 to 0.5, and the molar ratio of La / Mn is 0.05, 0.1, 0.15, or 0.

2. A method for preparing frangic acid, characterized in that the alkali is a mixture of one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate in any ratio.

2. In the aforementioned 5-hydroxymethylfurfural mixed reaction solution, the mass concentration of 5-hydroxymethylfurfural is 1 to 10%. The method for preparing frangic acid according to claim 1, characterized in that the molar ratio of the alkali to 5-hydroxymethylfurfural is 4:1 to 2:

1.

3. The process for preparing the polymetallic catalyst is as follows: Step S1 involves dissolving a manganese source, a vanadium source, a cobalt source, and a lanthanum source in ethanol and then ultrasonically dissolving them to prepare solution A. Step S2 involves dissolving citric acid in ethanol and preparing solution B by ultrasonic dissolution, A method for preparing a flanger carboxylic acid according to claim 1, characterized by comprising step S3, which involves vigorously stirring solution B, in which case solution A is injected into solution B during the vigorous stirring process, stirring until it becomes a viscous gel, leaving it at room temperature for 24 hours, drying it in a vacuum dryer at 60°C until it reaches a constant weight, then removing it and grinding it into a powder to obtain a polymetallic catalyst precursor, transferring the polymetallic catalyst to a muffle furnace, calcining it at 400°C for 5 hours, and further cooling, tableting and sieving to obtain a polymetallic catalyst.

4. In step S1, the manganese source is a mixture of one or more of manganese acetate and manganese chloride in any ratio. In step S1, the vanadium source is a mixture of one or more of sodium vanadate and vanadylacetylacetonate in any ratio. In step S1, the cobalt source is a mixture of one or more of cobalt nitrate and cobalt acetate in any ratio. In step S1, the lanthanum source is a mixture of one or more of lanthanum nitrate and lanthanum acetate in any ratio. In step S1, the molar ratio of vanadium elements in the vanadium source to manganese elements in the manganese source is (0.5 to 1):

1. In step S1, the molar ratio of cobalt elements in the cobalt source to manganese elements in the manganese source is (0.5 to 1):

1. In step S1, the molar ratio of lanthanum element in the lanthanum source to manganese element in the manganese source is selected from 0.05:1, 0.1:1, 0.15:1, or 0.2:

1. The method for preparing frangic acid according to claim 3, characterized in that in step S3, the molar ratio of manganese element from the manganese source, vanadium element from the vanadium source, cobalt element from the cobalt source, and lanthanum element from the lanthanum source in solution A to citric acid in solution B is (Mn + V + Co + La):citric acid = 1:1.

5.

5. The method for preparing a flanger carboxylic acid according to claim 3, characterized in that the size of the polymetallic catalyst is 10 to 300 mesh.

6. The method for preparing flanger carboxylic acid according to claim 1, characterized in that when the catalyst is packed into the bed of a fixed-bed reactor, the amount of catalyst packed is 100%.

7. The method for preparing flanger carboxylic acid according to claim 1, characterized in that the set value of the reaction temperature is 120 to 160°C, the set value of the reaction pressure is 0.5 to 4 MPa, and the gas is air or oxygen gas.

8. The method for preparing flanger carboxylic acid according to claim 1, characterized in that, in the process of pumping the 5-hydroxymethylfurfural mixed reaction solution to a fixed-bed reactor, the flow rate of the 5-hydroxymethylfurfural mixed reaction solution is 2 to 20 mL / min.

9. The specific process of acidification involves adding an acidifying reagent to the collected aqueous solution containing frangic acid salt, and acidifying the solution until the pH of the frangic acid salt-containing aqueous solution becomes less than 1, which causes a solid to precipitate. The method for preparing frangic acid according to claim 1, characterized in that the acidifying reagent is a mixture of one or more of hydrochloric acid, sulfuric acid, and nitric acid in any ratio.

10. The system includes a supply system, a reaction system, and a product processing system, wherein the supply end and discharge end of the reaction system are in communication with the supply system and the product processing system, respectively. The supply system includes a gas source and a metering pump. The reaction system includes a fixed-bed reactor and a reactor chamber that are in communication with each other, and the gas discharge end of the gas source and the discharge end of the metering pump are both in communication with the fixed-bed reactor. The product processing system includes a cooler, a gas-liquid separator, and a storage tank. The gas source includes a nitrogen gas source and an oxygen gas / air source, and the gas discharge ends of both the nitrogen gas source and the oxygen gas / air source are connected to a fixed-bed reactor via a gas discharge pipeline, and there are two gas mass flow controllers, each of which is attached to a gas discharge pipeline. The supply end of the metering pump is connected to a supply tank, a balance is provided at the bottom of the supply tank, a preheater is provided outside the discharge end of the metering pump, and a preheating furnace is provided outside the preheater. A heat-insulating jacket is provided at one end of the discharge end of the metering pump that is close to the fixed-bed reactor on the outside, and the heat-insulating jacket is located between the preheater and the fixed-bed reactor. The aforementioned gas discharge pipeline passes through the preheater and the heat-insulating jacket in sequence and communicates with the fixed-bed reactor. A discharge pipeline is provided at the discharge port of the reactor chamber, the discharge end of the fixed-bed reactor is connected to the discharge pipeline, the discharge pipeline passes through the cooler and is connected to a gas-liquid separator, and the discharge end of the gas-liquid separator is connected to a storage tank. The preparation apparatus for a method of preparing flange carboxylic acid according to any one of claims 1 to 9, characterized in that a sampling valve is further provided in the gas-liquid separator.

Images