A cyclic reaction device and a method for preparing sodium 3,3',4,4'-biphenyltetracarboxylate using the same

Abstract

The application relates to the technical field of fine chemical industry, in particular to a circulating reaction device and a method for preparing sodium 3,3',4,4'-biphenyltetracarboxylate by using the same. The circulating reaction device comprises: a batching kettle, a discharging pipeline and a circulating pipeline are arranged on the batching kettle; a reaction unit, an inlet pipeline and an outlet pipeline are arranged on the reaction unit; the inlet pipeline is communicated with the discharging pipeline; the outlet pipeline is communicated with the circulating pipeline; a filler area is arranged in the reaction unit; the fillers of the filler area at least comprise a catalyst; a pump is arranged on the inlet pipeline; a qualified reaction liquid kettle, a qualified liquid inlet pipeline is arranged on the qualified reaction liquid kettle, and the qualified liquid inlet pipeline is communicated with the outlet pipeline; a washing liquid kettle, a washing liquid first pipeline and a washing liquid second pipeline are arranged on the washing liquid kettle, the washing liquid first pipeline is communicated with the outlet pipeline, the inlet pipeline is communicated with the washing liquid second pipeline, and the washing liquid kettle is used for containing washing liquid for washing the catalyst. The application can effectively improve the reaction conversion rate, realize automatic production and improve the production efficiency.

Description

Technical Field

[0001] This application relates to the field of fine chemical technology, and in particular to a circulating reaction apparatus and a method for preparing sodium 3,3′,4,4′-biphenyltetracarboxylate using the same. Background Technology

[0002] 3,3′,4,4′-Biphenyltetracarboxylic acid dianhydride (BPDA) is a monomer of polyimides that can polymerize with multifunctional amines to form polyimides. Polyimides are the highest heat-resistant resins to date, and also possess excellent hydrolysis resistance, mechanical properties, and flexibility. They can be used to manufacture heat-resistant photosensitive resins, filters, liquid crystal displays, crosslinking adhesives for conductors and semiconductors, and also in lasers, lithium batteries, and protective materials used in space.

[0003] For example, Chinese patent CN101824327A discloses the use of liquid crystal polyimide as an alignment film material, and 3,3′,4,4′-biphenyltetracarboxylic acid dianhydride is the monomer for synthesizing the above material.

[0004] Currently, the main methods for preparing 3,3′,4,4′-biphenyltetracarboxylic acid dianhydride include: using chlorophthalic anhydride as a starting material, and proceeding through esterification, coupling, hydrolysis, and anhydride formation; or using chlorophthalic anhydride as a raw material to synthesize biphenyltetracarboxylic acid dianhydride under Pd / C catalysis; or using phthalic anhydride as a raw material to prepare it by oxidation in the presence of a Pd catalyst. For example, Chinese patent CN110563678A discloses a method for preparing 3,3′,4,4′-biphenyltetracarboxylic acid dianhydride, which uses phthalic anhydride as a raw material and prepares 3,3′,4,4′-biphenyltetracarboxylic acid dianhydride through chlorination, coupling, hydrolysis, acidification, and dehydration reactions.

[0005] In the above preparation methods, the preparation of sodium salt by coupling with chlorinated substrates faces significant technical bottlenecks in industrial production. Currently, mainstream domestic manufacturers use batch-type Pd / C catalytic coupling to prepare the above sodium salts. Repeated filtration and regeneration of Pd / C lead to Pd loss and reduced production efficiency, becoming a bottleneck for improving production technology and efficiency. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the purpose of this application is to provide a circulating reaction device and a method for preparing sodium 3,3′,4,4′-biphenyltetracarboxylate using it. By designing a new catalyst immobilization and loading scheme in the packing zone, and at the same time designing an integrated catalyst regeneration and washing scheme, automated production is achieved, thereby improving production efficiency and solving the problems in the prior art.

[0007] To achieve the above and other related objectives, this application provides a circulating reaction apparatus, comprising:

[0008] A batching vessel, which is equipped with a discharge pipe and a circulation pipe;

[0009] The reaction unit is equipped with an inlet pipe and an outlet pipe; the inlet pipe is connected to the outlet pipe; the outlet pipe is connected to the circulation pipe; the reaction unit is equipped with a packing zone; the packing in the packing zone includes at least a catalyst; and a pump is installed on the inlet pipe.

[0010] A qualified reaction vessel is provided with a qualified liquid inlet pipe, which is connected to the outlet pipe.

[0011] A washing liquid tank is provided with a first washing liquid pipe and a second washing liquid pipe. The first washing liquid pipe is connected to the outlet pipe, and the inlet pipe is connected to the second washing liquid pipe. The washing liquid tank is used to hold the washing liquid used for washing the catalyst.

[0012] In some embodiments of this application, the device further includes a first three-way valve, and the discharge pipe and the second washing liquid pipe are respectively connected to the inlet pipe through the first three-way valve.

[0013] In some embodiments of this application, the device further includes a second three-way valve, and the circulation pipeline and the qualified liquid inlet pipeline are respectively connected to the outlet pipeline through the second three-way valve.

[0014] In some embodiments of this application, the device further includes a third three-way valve, through which the outlet pipe is connected to the first washing liquid pipe.

[0015] In some embodiments of this application, the device further includes a fourth three-way valve and a third washing liquid pipeline, wherein the second washing liquid pipeline and the third washing liquid pipeline are connected through the fourth three-way valve, and the third washing liquid pipeline is connected to the washing liquid tank.

[0016] In some embodiments of this application, the pump is a peristaltic pump.

[0017] In some embodiments of this application, a back pressure valve is provided on the outlet pipe.

[0018] In some embodiments of this application, the batching vessel includes a first vessel body, a first stirring assembly is provided inside the first vessel body, and a first jacket is also provided on the first vessel body.

[0019] In some embodiments of this application, the qualified reaction vessel includes a second vessel body, a second stirring assembly is provided inside the second vessel body, and a second jacket is also provided on the second vessel body.

[0020] In some embodiments of this application, the washing liquid tank includes a third tank body, the third tank body is provided with a third stirring assembly, and the third tank body is also provided with a third jacket.

[0021] In some embodiments of this application, the washing solution is selected from one or more of methanol, aqueous nitric acid solution, and water. Preferably, the washing solution is a combination of methanol, aqueous nitric acid solution, and water.

[0022] In some embodiments of this application, the reaction unit is a reaction pipe with an outer diameter of 10 mm to 12 mm and an inner diameter of 7 mm to 9 mm.

[0023] In some embodiments of this application, the reaction unit is provided with a temperature control element.

[0024] In some embodiments of this application, the packing zone includes a first packing layer, a second packing layer, and a third packing layer sequentially from one end near the inlet pipe to one end near the outlet pipe. The first packing layer includes a first packing material, the second packing layer includes a second packing material, and the third packing layer includes a third packing material. The second packing material of the second packing layer includes at least a catalyst.

[0025] In some embodiments of this application, the first filler of the first filler layer includes glass spheres with a diameter of 0.5 mm to 2 mm, and the length of the first filler layer is 90 mm to 250 mm.

[0026] In some embodiments of this application, the length of the second filler layer is 90 mm to 250 mm.

[0027] In some embodiments of this application, the catalyst is a Pd / C supported catalyst. The second packing layer comprises a mixture of Pd / C supported catalyst, glass spheres, and diatomaceous earth.

[0028] In some embodiments of this application, the Pd / C supported spherical catalyst in the second packing layer is a (5%-10%) Pd / C supported spherical catalyst. Here, 5%-10% Pd / C supported catalyst means that the mass fraction of Pd in ​​the Pd / C catalyst is 5%-10%.

[0029] In some embodiments of this application, the catalyst has a packing volume of 0.5 cm³. 3 ~1.5cm 3 .

[0030] In some embodiments of this application, the Pd / C-supported spherical catalyst has a filling volume of 0.5 cm³ in the second packing layer. 3 ~1.5cm3 .

[0031] In some embodiments of this application, the filling volume of the glass spheres in the second filler layer is 2 cm³. 3 ~4cm 3 .

[0032] In some embodiments of this application, the diameter of the glass sphere in the second filler layer is 0.5 to 2 mm.

[0033] In some embodiments of this application, the diatomaceous earth filling volume in the second filler layer is 2 cm³. 3 ~4cm 3 .

[0034] In some embodiments of this application, the third filler of the third filler layer includes glass beads with a diameter of 0.5 to 2 mm.

[0035] In some embodiments of this application, the length of the third filler layer is 90 mm to 250 mm.

[0036] In some embodiments of this application, a packing fixing member is also included to prevent the packing from being washed away. The packing fixing member is a tempered mesh and is disposed between the third packing layer and the outlet pipe.

[0037] To achieve the above and other related objectives, this application also provides a method for preparing sodium 3,3′,4,4′-biphenyltetracarboxylate, comprising the following steps:

[0038] S1. Add the reaction raw materials to the mixing tank, and add packing material to the packing area of ​​the reaction unit, wherein the packing material includes at least a catalyst;

[0039] S2, connect the discharge pipe and the inlet pipe, and connect the outlet pipe and the circulation pipe to carry out a circulating reaction;

[0040] S3. At regular intervals, the central control unit takes samples to determine the reaction conversion rate and detect the pressure at the inlet pipe.

[0041] In some embodiments of this application, in step S1, the reaction raw materials include sodium m-chlorophthalate and sodium hydroxide, wherein the concentration of sodium m-chlorophthalate is 0.5 mol / L to 1.5 mol / L (preferably 1.0 mol / L), and the concentration of sodium hydroxide is 2.5 mol / L to 3 mol / L (preferably 2.7 mol / L).

[0042] In some embodiments of this application, in step S1, the packing includes a first packing, a second packing, and a third packing, and also includes a packing fixing member. The packing fixing member, the third packing, the second packing, and the first packing are sequentially filled from the end of the reaction unit near the outlet pipe to the end near the inlet pipe; wherein, the second packing includes at least a catalyst.

[0043] In some embodiments of this application, the first filler is a glass ball with a diameter of 0.5 to 2 mm (preferably 1 mm) and a length of 90 mm to 250 mm (preferably 100 mm).

[0044] In some embodiments of this application, the length of the second packing is 90 mm to 250 mm (preferably 100 mm).

[0045] In some embodiments of this application, the catalyst is a Pd / C supported catalyst.

[0046] In some embodiments of this application, the catalyst has a packing volume of 0.5 cm³. 3 ~1.5cm 3 .

[0047] In some embodiments of this application, the second filler is a mixture of Pd / C supported catalyst, glass beads, and diatomaceous earth.

[0048] In some embodiments of this application, the Pd / C supported catalyst is a (5%-10%) Pd / C supported catalyst, where 5%-10% Pd / C supported catalyst means that the mass fraction of Pd in ​​the Pd / C catalyst is 5%-10%.

[0049] In some embodiments of this application, the Pd / C supported catalyst is packed in the second packing material with a volume of 0.5 cm³. 3 ~1.5cm 3 (Preferred size: 1.0cm) 3 ).

[0050] In some embodiments of this application, the diameter of the glass spheres in the second filler is 0.5 mm to 1.5 mm (preferably 1.0 mm), and the filling volume of the glass spheres is 2 cm³. 3 ~4cm 3 .

[0051] In some embodiments of this application, the diatomaceous earth filling volume in the second filler is 2 cm³. 3 ~4cm 3 .

[0052] In some embodiments of this application, the third filler comprises glass spheres with a diameter of 0.5–2 mm and a filling volume of 2–4 cm³. 3 (preferably 3cm) 3 The length of the third packing is 90mm to 250mm.

[0053] In some embodiments of this application, the packing fixing element is a wire mesh.

[0054] In some embodiments of this application, during step S2, the batching vessel is heated to 60°C to 80°C (preferably 70°C) during the cyclic reaction.

[0055] In some embodiments of this application, during step S2, the reaction unit is heated to 120°C to 160°C (preferably 140°C) during the cyclic reaction.

[0056] In some embodiments of this application, during step S2, the flow rate during the cyclic reaction is 4 mL / min to 6 mL / min (preferably 5 mL / min).

[0057] In some embodiments of this application, in step S3, the time interval is the time for the reaction solution to circulate once.

[0058] In some embodiments of this application, in step S3, central control sampling is used to determine the reaction conversion rate and to detect the pressure at the pump outlet. Preferably, the pressure at the peristaltic pump outlet is detected.

[0059] The method for preparing sodium 3,3′,4,4′-biphenyltetracarboxylate also includes the following steps:

[0060] S4. Determine if the reaction conversion rate is greater than the target conversion rate, and determine if the pressure at the inlet pipe is greater than the maximum pressure limit.

[0061] When the pressure at the inlet pipe is greater than the maximum pressure limit and the reaction conversion rate is greater than the target conversion rate, connect the qualified liquid inlet pipe and the outlet pipe, discharge the material to the qualified reaction vessel, and proceed to step S5. After the catalyst is washed, proceed to step S1 or end.

[0062] When the pressure at the inlet pipe is greater than the maximum pressure limit and the reaction conversion rate is less than the target conversion rate, the reaction liquid in the reaction unit is drained into the mixing tank, and the process proceeds to step S5. After the catalyst is washed, the process proceeds to step S2.

[0063] When the pressure at the inlet pipe is less than the maximum pressure limit and the reaction conversion rate is greater than the target conversion rate, connect the qualified liquid inlet pipe and the outlet pipe, discharge the material to the qualified reaction liquid kettle, and proceed to step S1 or end.

[0064] When the pressure at the inlet pipe is less than the maximum pressure limit and the reaction conversion rate is less than the target conversion rate, proceed to step S3;

[0065] S5. Add washing liquid to the washing liquid tank, connect the outlet pipe to the first washing liquid pipe, and connect the inlet pipe to the second washing liquid pipe, so that the washing liquid enters the reaction unit to wash the catalyst.

[0066] In some embodiments of this application, in step S4, the reaction conversion rate is 95%;

[0067] In some embodiments of this application, in step S4, the maximum pressure limit is 0.6 MPa.

[0068] In some embodiments of this application, in step S5, the washing liquid is selected from one or more of methanol, aqueous nitric acid solution, and water; preferably, the washing liquid is a combination of methanol, aqueous nitric acid solution, and water.

[0069] In some embodiments of this application, step S5 further includes connecting the second washing liquid pipe to the third washing liquid pipe, and the third washing liquid pipe to the washing liquid tank.

[0070] Compared with the prior art, the beneficial effects of this application are as follows:

[0071] According to the circulating reaction apparatus and the method for preparing sodium 3,3′,4,4′-biphenyltetracarboxylate described in the above embodiments, the washing liquid tank and the reaction unit are connected, and the catalyst is washed by the washing liquid in the washing liquid tank, forming an integrated catalyst regeneration and washing scheme. This achieves automated production, simplifies labor costs, and improves production efficiency. In a preferred embodiment, especially by selecting a suitable washing liquid, such as methanol, nitric acid aqueous solution, and pure water, to wash the catalyst (especially the Pd / C supported catalyst) sequentially, the Pd / C supported catalyst can be better regenerated.

[0072] According to the circulating reaction apparatus and method for preparing sodium 3,3′,4,4′-biphenyltetracarboxylate described in the above embodiments, the packing zone in the reaction unit is filled with a mixture of Pd / C supported spherical catalyst, glass spheres, and diatomaceous earth. Therefore, using this apparatus to prepare sodium 3,3′,4,4′-biphenyltetracarboxylate can effectively improve the reaction conversion rate. In a preferred embodiment, the second packing is a mixture of glass spheres, 10% Pd / C supported catalyst, and diatomaceous earth. Glass spheres facilitate heat transfer and create a flowable solid space, while diatomaceous earth can relatively fix the space created by the glass spheres. Diatomaceous earth can also promptly intercept and disperse particles of the supported catalyst that break off after being impacted by the flowing phase, thus not significantly increasing the pipeline pressure. In a further preferred embodiment, by appropriately increasing the amount of glass spheres or diatomaceous earth in the second packing, the apparatus resistance can be reduced and the operation can be made more stable. Furthermore, when the second packing contains a mixture of Pd / C supported spherical catalyst, glass spheres, and diatomaceous earth, the number of cycles is significantly better than that of the scheme where the second packing does not contain glass spheres or diatomaceous earth. Attached Figure Description

[0073] Figure 1 The diagram shown is a schematic representation of the cyclic reaction apparatus of this application.

[0074] Figure 2 The diagram shown is a structural schematic of the packing zone in the reaction unit of the circulating reaction apparatus of this application.

[0075] Component designation explanation

[0076] 1. Batching vessel

[0077] 101 First vessel

[0078] 102 First stirring component

[0079] 1021 First Stirring Rod

[0080] 1022 First Stirring Blade

[0081] 103 First Jacket

[0082] 2 Reaction Unit

[0083] 201 Packing Area

[0084] 2011 First packing layer

[0085] 2012 Second packing layer

[0086] 2013 Third packing layer

[0087] 3. Qualified reaction vessel

[0088] 301 Second reactor body

[0089] 302 Second stirring component

[0090] 3021 Second Stirring Rod

[0091] 3022 Second Agitator

[0092] 303 Second Jacket

[0093] 4. Washing liquid tank

[0094] 401 Third reactor body

[0095] 402 Third stirring component

[0096] 4021 Third Stirring Rod

[0097] 4022 Third Agitator

[0098] 403 Third Jacket

[0099] 5. Discharge pipe

[0100] 6. Circulation Pipeline

[0101] 7. Inlet pipe

[0102] 8. Export Pipeline

[0103] 9. Qualified liquid inlet pipeline

[0104] 10. First pipe for washing liquid

[0105] 11. Second pipe for washing liquid

[0106] 12. Washing liquid third pipe

[0107] 13 pumps

[0108] 14 Back pressure valve

[0109] 15 First three-way valve

[0110] 16 Second Three-Way Valve

[0111] 17 Third three-way valve

[0112] 18. Fourth three-way valve Detailed Implementation

[0113] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0114] In the description of this application, it should be noted that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are only for illustrative purposes to aid those skilled in the art and are not intended to limit the implementation of this application. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of this application, should still fall within the scope of the technical content disclosed in this application. Furthermore, the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0115] In the description of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0116] Furthermore, in the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0117] In the following examples, the catalyst supported by 10% Pd / C was made of coconut shell, which was purchased from Xi'an Kaili New Materials Co., Ltd.

[0118] In the following examples, unless otherwise stated, all reactants are commercially available products.

[0119] <Example 1>

[0120] like Figure 1 As shown, the embodiments of this application relate to a circulating reaction apparatus for preparing sodium 3,3′,4,4′-biphenyltetracarboxylate, including a batching vessel 1, a reaction unit 2, a qualified reaction liquid vessel 3, and a washing liquid vessel 4.

[0121] In the circulating reaction apparatus provided in this application, the mixing tank 1 is used to store the starting materials and / or intermediate products of the reaction, such as... Figure 1 The batching vessel 1 is equipped with a discharge pipe 5 and a circulation pipe 6.

[0122] Furthermore, the mixing vessel 1 includes a first vessel body 101, within which a first stirring assembly 102 is provided, and a first jacket 103 is also provided on the first vessel body 101. For example, the first jacket 103 is located on the outside of the second vessel body 301. The first stirring assembly 102 includes a first stirring rod 1021 and a first stirring paddle 1022, and the first stirring paddle 1022 stirs the liquid in the mixing vessel 1.

[0123] In the circulating reaction apparatus provided in this application, such as Figure 1 The reaction unit 2 is provided with an inlet pipe 7 and an outlet pipe 8; the inlet pipe 7 is connected to the discharge pipe 5; and the outlet pipe 8 is connected to the circulation pipe 6.

[0124] Further, reaction unit 2 is a reaction pipe with an outer diameter of 10mm to 12mm (10mm in this embodiment) and an inner diameter of 7mm to 9mm (8mm in this embodiment). The material of the reaction pipe can be, for example, soluble polytetrafluoroethylene. The reaction pipe includes an inlet and an outlet, with the inlet connected to inlet pipe 7 and the outlet connected to outlet pipe 8.

[0125] Furthermore, the reaction unit 2 is provided with a packing zone 201; the packing material in the packing zone 201 includes at least a catalyst. The catalyst includes a Pd / C supported catalyst.

[0126] Furthermore, the packing zone 201, from one end near the inlet pipe 7 to the other end near the outlet pipe 8, sequentially includes a first packing layer 2011, a second packing layer 2012, and a third packing layer 2013. The first packing layer 2011 includes a first packing material, the second packing layer 2012 includes a second packing material, and the third packing layer 2013 includes a third packing material. The second packing material in the second packing layer 2012 is a mixture of Pd / C supported catalyst, glass beads, and diatomaceous earth. Figure 2 This is a schematic diagram of the structure of the first packing layer 2011, the second packing layer 2012, and the third packing layer 2013, intended only to illustrate that the pipeline is a straight pipe. In this application, the reaction pipeline can be a serpentine pipe, a straight pipe, etc., and the shape of the reaction pipeline does not affect the reaction process.

[0127] Furthermore, the first filler of the first filler layer 2011 includes glass spheres with a diameter of 0.5 mm to 2 mm (1 mm in this embodiment) and a length of 90 mm to 250 mm (100 mm in this embodiment).

[0128] Furthermore, the length of the second filler layer 2012 is 90mm to 250mm (in this embodiment, the length of the second filler layer 2012 is 100mm).

[0129] Furthermore, the packing volume of the Pd / C supported catalyst is 0.5 cm³. 3 ~1.5cm 3 (In this embodiment, it is 1cm) 3 The Pd / C supported catalyst can be, for example, a (5%-10%) Pd / C supported spherical catalyst, and in this embodiment, a 10% Pd / C supported spherical catalyst.

[0130] Furthermore, in this embodiment, the Pd / C supported catalyst, glass spheres, and diatomaceous earth mixture has a packing volume of 0.5 cm³ for the Pd / C supported catalyst. 3 ~1.5cm 3 (In this embodiment, the packing volume of the Pd / C supported catalyst is 1 cm³) 3 The filling volume of the glass sphere is 2 cm³. 3 ~4cm 3 (In this embodiment, the filling volume of the glass sphere is 2cm³) 3 The diameter of the glass sphere is 0.5–2 mm (1 mm in this embodiment), and the filling volume of the diatomaceous earth is 2 cm³. 3 ~4cm 3 (In this embodiment, the filling volume of diatomaceous earth is 2 cm³) 3 )

[0131] Furthermore, the third filler layer 2013 comprises glass spheres, the diameter of which is between 0.5 and 2 mm, with an average diameter of 1 mm. The length of the third filler layer 2013 is between 90 mm and 250 mm (in this embodiment, the total filling amount of glass spheres is 3 cm). 3 ).

[0132] Furthermore, it also includes a packing retainer for preventing the packing from being washed away. The packing retainer is a tempered steel mesh used to intercept the first packing, the second packing, and the third packing. The packing retainer is located between the third packing layer 2013 and the outlet pipe 8.

[0133] Furthermore, the reaction unit 2 is equipped with a temperature control element for controlling the internal temperature of the reaction unit 2. The temperature control element can be, for example, any existing heating element, and can be arranged inside or outside the reaction pipe.

[0134] Furthermore, such as Figure 1A pump is installed on the inlet pipe 7. Preferably, a peristaltic pump is installed on the inlet pipe 7 for transporting liquid and controlling the flow rate.

[0135] Furthermore, such as Figure 1 The outlet pipe 8 is equipped with a back pressure valve 14 for regulating the pipe pressure.

[0136] In the circulating reaction apparatus provided in this application, the qualified reaction vessel 3 is used to collect qualified products, such as... Figure 1 The qualified reaction vessel 3 is equipped with a qualified liquid inlet pipe 9, which is connected to the outlet pipe 8.

[0137] Furthermore, the qualified reaction vessel 3 includes a second vessel body 301, within which a second stirring assembly 302 is provided, and a second jacket 303 is also provided on the second vessel body 301. For example, the second jacket 303 is located on the outside of the second vessel body 301. The second stirring assembly 302 includes a second stirring rod 3021 and a second stirring paddle 3022, and the qualified liquid in the qualified reaction vessel 3 is stirred by the second stirring paddle 3022.

[0138] In the circulating reaction apparatus provided in this application, the washing liquid tank 4 is used to store the washing liquid, such as... Figure 1 The washing liquid tank 4 is provided with a first washing liquid pipe 10 and a second washing liquid pipe 11. The first washing liquid pipe 10 is connected to the outlet pipe 8, and the inlet pipe 7 is connected to the second washing liquid pipe 11.

[0139] Furthermore, the washing liquid tank 4 includes a third tank body 401, within which a third stirring assembly 402 is provided, and a third jacket 403 is also provided on the third tank body 401. For example, the third jacket 403 is located on the outside of the third tank body 401. The third stirring assembly 402 includes a third stirring rod 4021 and a third stirring paddle 4022, and the washing liquid in the washing liquid tank 4 is stirred by the third stirring paddle 4022.

[0140] The circulating reaction apparatus provided in this application further includes a first three-way valve 15, through which the discharge pipe 5 and the second washing liquid pipe 11 are respectively connected to the inlet pipe 7. The apparatus also includes a second three-way valve 16, through which the circulating pipe 6 and the qualified liquid inlet pipe 9 are respectively connected to the outlet pipe 8. Finally, the apparatus includes a third three-way valve 17, through which the outlet pipe 8 is connected to the first washing liquid pipe 10.

[0141] In a preferred embodiment, the device further includes a fourth three-way valve 18 and a third washing liquid pipeline 12. The second washing liquid pipeline 11 and the third washing liquid pipeline 12 are connected via the fourth three-way valve 18, and the third washing liquid pipeline 12 is connected to the washing liquid vessel 4. Considering that sometimes the pressure at the bottom of the washing liquid vessel 4 is too high, making it difficult for the liquid in the reaction unit 2 to enter the washing liquid vessel 4, the fourth three-way valve 18 connects the second washing liquid pipeline 11 and the third washing liquid pipeline 12, allowing the liquid to enter the washing liquid vessel 4 from above.

[0142] The working process of the circulating reaction device in this application includes the following steps: packing step, circulating reaction step, collecting qualified products step, and washing step, specifically:

[0143] The packing process specifically includes: first, in the packing area 201 of reaction unit 2, from the end of reaction unit 2 near the outlet pipe 8 to the end near the inlet pipe 7, the aforementioned packing fixture, third packing, second packing and first packing are sequentially packed.

[0144] The cyclic reaction steps include: connecting the discharge pipe 5 and the inlet pipe 7 by adjusting the first three-way valve 15, allowing the raw materials or intermediate products in the batching vessel 1 to enter the reaction unit 2 through the discharge pipe 5; further connecting the outlet pipe 8 and the circulation pipe 6 by adjusting the second three-way valve 16, allowing the reaction liquid in the reaction unit 2 to return to the batching vessel 1 through the outlet pipe 8 and the circulation pipe 6. This forms a circulation loop between the batching vessel 1 and the reaction unit 2.

[0145] The steps for collecting qualified products include: connecting the discharge pipe 5 and the inlet pipe 7 by adjusting the first three-way valve 15, allowing the raw materials or intermediate products in the batching vessel 1 to enter the reaction unit 2 through the discharge pipe 5; and further connecting the outlet pipe 8 and the qualified liquid inlet pipe 9 by adjusting the second three-way valve 16, so that the qualified reaction liquid after the reaction in the reaction unit 2 enters the qualified reaction liquid vessel 3 through the outlet pipe 8 and the qualified liquid inlet pipe 9.

[0146] The washing steps include: when the catalyst in the packing zone 201 of reaction unit 2 needs to be washed, the first washing liquid pipe 10 is connected to the outlet pipe 8 by adjusting the second three-way valve 16, so that the washing liquid enters the packing zone 201 of reaction unit 2 from the washing liquid tank 4 to wash the catalyst. The first washing liquid pipe 10 is connected to the inlet pipe 7 by adjusting the first three-way valve 15. After washing, the washing liquid enters the washing liquid tank 4 through the inlet pipe 7 and the second washing liquid pipe 11. In some cases, considering that the pressure at the bottom of the washing liquid tank 4 may be too high and the liquid in reaction unit 2 may not easily enter the washing liquid tank 4, the second washing liquid pipe 11 is connected to the third washing liquid pipe 12 by the fourth three-way valve 18. The third washing liquid pipe 12 is further connected to the washing liquid tank 4, and the washing liquid enters the washing liquid tank 4 from above.

[0147] <Example 2>

[0148] A method for preparing sodium 3,3′,4,4′-biphenyltetracarboxylate using the apparatus provided in Example 1 includes the following steps:

[0149] S1. Add sodium m-chlorophthalate and sodium hydroxide solution to the mixing tank 1, and fill the reaction pipeline with 10% Pd / C supported spherical catalyst. The reaction pipeline is a serpentine pipeline (although it is a serpentine pipeline in this embodiment, it can be any other shape in other embodiments. The shape of the reaction pipeline will not affect the reaction). The device is purged with nitrogen.

[0150] S2. Adjust the second three-way valve 16 to connect the circulation pipe 6 with the outlet pipe 8; adjust the first three-way valve 15 to connect the discharge pipe 5 with the inlet pipe 7; adjust the third three-way valve 17 to connect the outlet pipe 8 with the circulation pipe 6 to carry out the circulation reaction.

[0151] S3. At regular intervals, the central control unit takes samples to determine the reaction conversion rate and detects the pressure at the outlet of the peristaltic pump.

[0152] S4. Central control sampling to determine if the reaction conversion rate is greater than the target conversion rate.

[0153] Simultaneously, the pressure at the outlet of the peristaltic pump is detected to determine whether the pressure at the outlet of the peristaltic pump is greater than the maximum pressure limit;

[0154] When the pressure at the outlet of the peristaltic pump is greater than the maximum pressure limit and the reaction conversion rate is greater than the target conversion rate, adjust the second three-way valve 16 to connect the qualified liquid inlet pipe 9 with the outlet pipe 8, discharge the material to the qualified reaction liquid vessel 3, and enter S5. After the catalyst is washed, enter S1 or end.

[0155] When the pressure at the outlet of the peristaltic pump is greater than the maximum pressure limit and the reaction conversion rate is less than the target conversion rate, the reaction liquid in the pipeline is drained into the mixing tank 1 and enters S5. After the catalyst is washed, it enters S2.

[0156] When the pressure at the outlet of the peristaltic pump is less than the maximum pressure limit and the reaction conversion rate is greater than the target conversion rate, adjust the second three-way valve 16 to connect the qualified liquid inlet pipe 9 with the outlet pipe 8, and discharge the material to the qualified reaction liquid kettle 3, and enter S1 or end.

[0157] When the pressure at the outlet of the peristaltic pump is less than the maximum pressure limit and the reaction conversion rate is less than the target conversion rate, proceed to S3;

[0158] S5. Add washing liquid to washing liquid tank 4, adjust the first three-way valve 15 to connect inlet pipe 7 to washing liquid second pipe 11; adjust the third three-way valve 17 to connect outlet pipe 8 to washing liquid first pipe 10; adjust the fourth three-way valve 18 to connect washing liquid third pipe 12 to washing liquid second pipe 11, so that washing liquid enters the reaction pipe through washing liquid first pipe 10 and outlet pipe 8 to wash the catalyst. If multiple washing liquids are required to wash the catalyst in sequence, the washing liquid after washing can be discharged into washing liquid tank 4. After discharge, the next washing liquid is replaced until all the required washing liquids are used. In this embodiment, the catalyst needs to be washed with methanol, 1wt% nitric acid aqueous solution and pure water in sequence. In other embodiments, one or more washing liquids can be selected according to actual needs.

[0159] <Example 3>

[0160] A method for preparing sodium 3,3′,4,4′-biphenyltetracarboxylate includes the following steps:

[0161] S1. Add 200 mL of reaction solution (sodium chlorophthalate concentration of 1 mol / L and sodium hydroxide concentration of 2.7 mol / L) to mixing tank 1. Fill the reaction pipeline with packing material, starting from the end near the outlet pipe 8 and ending near the inlet pipe 7, sequentially filling with wire mesh (to prevent the packing material from being washed away by the reaction solution), and then the third packing material (3 cm). 3 Glass spheres with a diameter of 0.5-2mm), and a second filler (filled with 1cm of... 3 10% Pd / C supported catalyst, 2cm 3 A glass ball with a diameter of 1mm and a diameter of 2cm 3 Diatomaceous earth, after being mixed evenly, is filled in a length of 100mm. Near the inlet, the first filler (glass spheres with a diameter of 1mm) is filled in a length of 200mm; the device is purged with nitrogen.

[0162] S2. Adjust the second three-way valve 16 to connect the circulation pipe 6 to the outlet pipe 8; adjust the first three-way valve 15 to connect the discharge pipe 5 to the inlet pipe 7; adjust the third three-way valve 17 to connect the outlet pipe 8 to the circulation pipe 6, raise the temperature of the mixing vessel 1 to 70℃, raise the temperature of the reaction pipe to 140℃, and set the flow rate to 5mL / min; then carry out the circulation reaction.

[0163] S3. Samples were taken every 40 minutes (approximately the time it takes for 200 mL of reaction solution to circulate once) to determine the reaction conversion rate and to detect the pressure at the outlet of the peristaltic pump. Some data are shown in Table 1.

[0164] S4. Central control sampling to determine if the reaction conversion rate is greater than 95%.

[0165] At the same time, the pressure at the outlet of the peristaltic pump is detected to determine whether the pressure at the outlet of the peristaltic pump is greater than 0.6 MPa;

[0166] When the pressure at the outlet of the peristaltic pump is greater than 0.6 MPa and the reaction conversion rate is greater than 95%, adjust the second three-way valve 16 to connect the qualified liquid inlet pipe 9 with the outlet pipe 8, discharge the material to the qualified reaction liquid kettle 3, enter S5, and after the catalyst is washed, enter S1 or end.

[0167] When the pressure at the outlet of the peristaltic pump is greater than 0.6 MPa and the reaction conversion rate is less than 95%, the reaction liquid in the pipeline is drained into the mixing tank 1 and enters S5. After the catalyst is washed, it enters S2.

[0168] When the pressure at the outlet of the peristaltic pump is less than 0.6 MPa and the reaction conversion rate is greater than 95%, adjust the second three-way valve 16 to connect the qualified liquid inlet pipe 9 with the outlet pipe 8, and discharge the material to the qualified reaction liquid kettle 3, and enter S1 or end the process.

[0169] When the pressure at the outlet of the peristaltic pump is less than 0.6 MPa and the reaction conversion rate is less than 95%, it enters S3;

[0170] S5. Add washing liquid to washing liquid tank 4, adjust the first three-way valve 15 to connect inlet pipe 7 to washing liquid second pipe 11; adjust the third three-way valve 17 to connect outlet pipe 8 to washing liquid first pipe 10; adjust the fourth three-way valve 18 to connect washing liquid third pipe 12 to washing liquid second pipe 11, so that washing liquid enters the reaction pipe through washing liquid first pipe 10 and outlet pipe 8 to wash the catalyst. If multiple washing liquids are required to wash the catalyst in sequence, the washing liquid after washing can be discharged into washing liquid tank 4. After discharge, the next washing liquid is replaced until all the required washing liquids are used. In this embodiment, each time the catalyst is washed, 100mL of methanol, 100mL of 1wt% nitric acid aqueous solution and 100mL of pure water are used in sequence. In other embodiments, one or more washing liquids can be selected according to actual needs.

[0171] Table 1

[0172]

[0173] <Example 4>

[0174] This embodiment is based on Embodiment 3, except that the amount of glass beads in the second packing material filled into the reaction pipeline is 4 cm. 3 Except for the steps described in Example 3, the rest of the steps are the same.

[0175] After 30 cycles, the reaction conversion rate was measured to be 95.5%. However, after 30 cycles, the apparatus used a 4cm... 3 The glass bulb peristaltic pump has an outlet pressure of 0.40 MPa, which is higher than that of a 2cm pump. 3 The glass bulb peristaltic pump outlet pressure of 0.43MPa is smaller, resulting in less device resistance and smoother operation.

[0176] <Example 5>

[0177] This embodiment is based on Embodiment 3, except that the amount of diatomaceous earth in the second packing material filled into the reaction pipeline is 4 cm. 3 Except for the steps described in Example 3, the rest of the steps are the same.

[0178] After 30 cycles, the reaction conversion rate was measured to be 95.4%. However, after 30 cycles, the apparatus used a 4cm... 3 The outlet pressure of the diatomaceous earth peristaltic pump is 0.41 MPa, which is higher than that of a 2cm pump. 3 The outlet pressure of the peristaltic pump made of diatomaceous earth is 0.43MPa, which is lower, resulting in less resistance and smoother operation.

[0179] <Example 6>

[0180] stress test

[0181] Three different reaction apparatuses using different second packing materials were tested. Except for the second packing material, the rest of the reaction apparatuses were identical to those in Example 1.

[0182] Group A: The second packing material consists of 1cm 3 10% Pd / C supported catalyst, 2cm 3 A glass ball with a diameter of 1mm and a diameter of 2cm 3 It is made by uniformly mixing diatomaceous earth.

[0183] Group B: The second packing material consists of 1cm 3 10% Pd / C supported catalyst, 2cm 3 It is made by uniformly mixing diatomaceous earth.

[0184] Group C: The second packing material consists of 1cm 3 10% Pd / C supported catalyst, 2cm 3 It is made by uniformly mixing glass spheres with a diameter of 1mm.

[0185] The testing method is as follows:

[0186] S1. Add 200 mL of reaction solution (sodium chlorophthalate concentration of 1 mol / L and sodium hydroxide concentration of 2.7 mol / L) to mixing tank 1. Fill the reaction pipeline with packing material, successively filling with wire mesh (to prevent the packing material from being washed away by the reaction solution), and then the third packing material (3 cm). 3 The first packing material (glass spheres with a diameter of 0.5-2mm) is used as the second packing material, and the first packing material (glass spheres with a diameter of 1mm) is used near the inlet with a packing length of 200mm; the device is purged with nitrogen.

[0187] S2. Adjust the second three-way valve 16 to connect the circulation pipe 6 with the outlet pipe 8; adjust the first three-way valve 15 to connect the discharge pipe 5 with the inlet pipe 7; adjust the third three-way valve 17 to connect the outlet pipe 8 with the circulation pipe 6, raise the temperature of the mixing tank 1 to 70°C, raise the temperature of the reaction pipe to 140°C, and set the flow rate to 5 mL / min.

[0188] S3. Perform a cyclic reaction, taking samples every 40 minutes (approximately the time it takes to circulate 200 mL of reaction solution once) to determine the reaction conversion rate and monitor the pressure at the peristaltic pump outlet. When the pressure at the peristaltic pump outlet is detected to be ≥0.6 MPa, the system crashes and the test ends. Some data are shown in Table 2.

[0189] Table 2

[0190]

[0191]

[0192] *The reaction conversion rate reaches 100% after 50 cycles.

[0193] The role and effect of the embodiments

[0194] According to the circulating reaction device and the method for preparing sodium 3,3′,4,4′-biphenyltetracarboxylate involved in the above embodiments, after connecting the washing liquid tank 4 and the reaction unit 2, the catalyst is washed by the washing liquid in the washing liquid tank 4, forming an integrated catalyst regeneration and washing scheme, realizing automated production, simplifying labor costs, and improving production efficiency.

[0195] Furthermore, selecting a suitable washing solution, such as methanol, nitric acid aqueous solution, and pure water, to wash the catalyst (especially the Pd / C supported catalyst) in sequence, can better regenerate the Pd / C supported catalyst.

[0196] Furthermore, the packing zone in the reaction unit is filled with a mixture of Pd / C-supported spherical catalyst, glass spheres, and diatomaceous earth. Therefore, using this device to prepare sodium 3,3′,4,4′-biphenyltetracarboxylate can effectively improve the reaction conversion rate.

[0197] Furthermore, since the second packing material is a mixture of glass spheres, 10% Pd / C supported catalyst, and diatomaceous earth, the glass spheres are beneficial for heat transfer and creating a flowable solid space. The diatomaceous earth can relatively fix the space created by the glass spheres. The diatomaceous earth can also intercept and disperse the particles that break off after the supported catalyst is impacted by the flowing phase. Therefore, it will not significantly increase the pipeline pressure.

[0198] Furthermore, the second filler layer is 1 cm thick. 3 Pd / C supported spherical catalysts, 2cm 3 Glass ball and 2cm 3 When using diatomaceous earth, the reaction conversion rate was measured to be 95.8% after 30 cycles, and the peristaltic pump outlet pressure was 0.43 MPa.

[0199] When the amount of glass beads in the second packing is increased, for example, to 4 cm, 3 After 30 cycles, the reaction conversion rate was measured to be 95.5%. However, after 30 cycles of the device, a 4cm [device] was used. 3 The glass bulb peristaltic pump has an outlet pressure of 0.40 MPa, which is higher than that of a 2cm pump. 3 The peristaltic pump outlet pressure of 0.43 MPa using glass beads is lower, resulting in less resistance and smoother operation. Therefore, appropriately increasing the amount of glass beads in the second packing can further reduce resistance and improve operational stability.

[0200] When the amount of diatomaceous earth in the second packing material is increased, for example, when the amount of diatomaceous earth in the second packing material is increased to 4 cm...3 After 30 cycles, the reaction conversion rate was measured to be 95.5%, and after another 30 cycles, it was measured to be 95.4%. However, after the apparatus was cycled 30 times, a 4cm... 3 The outlet pressure of the diatomaceous earth peristaltic pump is 0.41 MPa, which is higher than that of a 2cm pump. 3 The outlet pressure of a peristaltic pump using diatomaceous earth is less than 0.43 MPa. Therefore, appropriately increasing the amount of diatomaceous earth in the second packing can reduce the resistance of the device and make its operation more stable.

[0201] Furthermore, when the second packing material is a mixture of Pd / C-supported spherical catalyst, glass spheres, and diatomaceous earth, the peristaltic pump outlet pressure is less than 0.6 MPa after less than 50 cycles. After 50 cycles, the peristaltic pump outlet pressure is >0.6 MPa, and the reaction conversion rate reaches 100%. When the second packing material does not contain diatomaceous earth, the peristaltic pump outlet pressure is >0.6 MPa after 5 cycles; when the second packing material does not contain glass spheres, the peristaltic pump outlet pressure is >0.6 MPa after 25 cycles. It is evident that when the second packing material does not contain glass spheres or diatomaceous earth, the number of cycles is significantly reduced. Therefore, the preferred technical solution for the second packing material is a mixture of Pd / C-supported spherical catalyst, glass spheres, and diatomaceous earth.

[0202] Furthermore, by setting packing fixing components, especially tempered mesh, it is possible to prevent the packing from being washed away.

[0203] The above embodiments are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention.

[0204] In summary, this application effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0205] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this application should still be covered by the claims of this application.

Claims

1. A method for preparing sodium 3,3',4,4'-biphenyltetracarboxylate, comprising using a circulating reaction apparatus, characterized in that, The circulating reaction apparatus includes: A batching vessel (1) is provided with a discharge pipe (5) and a circulation pipe (6). The reaction unit (2) is provided with an inlet pipe (7) and an outlet pipe (8); the inlet pipe (7) is connected to the discharge pipe (5); the outlet pipe (8) is connected to the circulation pipe (6); the reaction unit (2) is provided with a packing zone (201); the packing in the packing zone (201) includes at least a catalyst; the inlet pipe (7) is provided with a pump (13); A qualified reaction vessel (3) is provided with a qualified liquid inlet pipe (9), which is connected to the outlet pipe (8). The washing liquid tank (4) is provided with a first washing liquid pipe (10) and a second washing liquid pipe (11). The first washing liquid pipe (10) is connected to the outlet pipe (8), and the inlet pipe (7) is connected to the second washing liquid pipe (11). The washing liquid tank (4) is used to hold the washing liquid used to wash the catalyst. The method for preparing sodium 3,3',4,4'-biphenyltetracarboxylate includes the following steps: S1. Add the reaction raw materials to the mixing tank (1) and add packing material to the packing area (201) of the reaction unit (2). The packing material includes at least a catalyst. The reaction raw materials include sodium m-chlorophthalate and sodium hydroxide. S2, connect the discharge pipe (5) and the inlet pipe (7), connect the outlet pipe (8) and the circulation pipe (6) to carry out the circulation reaction; S3. At regular intervals, the central control unit takes samples to determine the reaction conversion rate and detects the pressure at the inlet pipe (7).

2. The method for preparing sodium 3,3',4,4'-biphenyltetracarboxylate according to claim 1, characterized in that, It also includes one or more of the following features: A1) The device also includes a first three-way valve (15), and the discharge pipe (5) and the washing liquid second pipe (11) are respectively connected to the inlet pipe (7) through the first three-way valve (15); A2) The device also includes a second three-way valve (16), and the circulation pipeline (6) and the qualified liquid inlet pipeline (9) are respectively connected to the outlet pipeline (8) through the second three-way valve (16); A3) The device further includes a third three-way valve (17), and the outlet pipe (8) is connected to the first washing liquid pipe (10) through the third three-way valve (17); A4) The device also includes a fourth three-way valve (18) and a third washing liquid pipeline (12). The second washing liquid pipeline (11) and the third washing liquid pipeline (12) are connected through the fourth three-way valve (18). The third washing liquid pipeline (12) is connected to the washing liquid tank (4). A5) The pump (13) is a peristaltic pump; A6) A back pressure valve (14) is provided on the outlet pipe (8); A7) The batching vessel (1) includes a first vessel body (101), a first stirring assembly (102) is provided inside the first vessel body (101), and a first jacket (103) is also provided on the first vessel body (101). A8) The qualified reaction vessel (3) includes a second vessel body (301), a second stirring assembly (302) is provided inside the second vessel body (301), and a second jacket (303) is also provided on the second vessel body (301). A9) The washing liquid tank (4) includes a third tank body (401), a third stirring assembly (402) is provided inside the third tank body (401), and a third jacket (403) is also provided on the third tank body (401). A10) The washing solution is selected from one or more of methanol, aqueous nitric acid solution and water.

3. The method for preparing sodium 3,3',4,4'-biphenyltetracarboxylate as described in claim 1, characterized in that, It also includes one or more of the following features: B1) The reaction unit (2) is a reaction pipe with an outer diameter of 10mm~12mm and an inner diameter of 7mm~9mm. B2) The reaction unit (2) is equipped with a temperature control device; B3) The packing zone (201) includes a first packing layer (2011), a second packing layer (2012) and a third packing layer (2013) from one end near the inlet pipe (7) to one end near the outlet pipe (8). The first packing layer (2011) includes a first packing, the second packing layer (2012) includes a second packing, and the third packing layer (2013) includes a third packing. The second packing of the second packing layer (2012) includes at least a catalyst.

4. The method for preparing sodium 3,3',4,4'-biphenyltetracarboxylate as described in claim 3, characterized in that, It also includes one or more of the following features: B31) The first filler of the first filler layer (2011) includes glass spheres with a diameter of 0.5 mm to 2 mm, and the length of the first filler layer (2011) is 90 mm to 250 mm. B32) The length of the second filler layer (2012) is 90mm~250mm; B33) The catalyst is a Pd / C supported catalyst; the filler of the second packing layer (2012) is a mixture of Pd / C supported catalyst, glass spheres and diatomaceous earth; B34) The catalyst has a packing volume of 0.5 cm³. 3 ~1.5 cm 3 ; B35) The third packing of the third packing layer (2013) includes glass beads with a diameter of 0.5~2mm; B36) The length of the third filler layer (2013) is 90mm~250mm; B37) also includes a packing retainer for preventing the packing from being washed away, the packing retainer being a tempered mesh, the packing retainer being disposed between the third packing layer (2013) and the outlet pipe (8).

5. The method for preparing sodium 3,3',4,4'-biphenyltetracarboxylate as described in claim 4, characterized in that, It also includes one or more of the following features: B331) In the second packing layer (2012), the Pd / C supported catalyst is (5%-10%) Pd / C supported catalyst; B332) In the second packing layer (2012), the Pd / C supported catalyst has a packing volume of 0.5 cm³. 3 ~1.5cm 3 ; B333) In the second filler layer (2012), the filling volume of the glass spheres is 2 cm³. 3 ~4cm 3 ; B334) In the second filler layer (2012), the diameter of the glass sphere is 0.5~2mm; B335) In the second filler layer (2012), the diatomaceous earth filling volume is 2 cm³. 3 ~4 cm 3 .

6. The method for preparing sodium 3,3',4,4'-biphenyltetracarboxylate according to claim 1, characterized in that, The method further includes one or more of the following features: C1) In step S1, the concentration of sodium m-chlorophthalate is 0.5 mol / L to 1.5 mol / L, and the concentration of sodium hydroxide is 2.5 mol / L to 3 mol / L; C2) In step S1, the packing includes a first packing, a second packing and a third packing, and also includes a packing fixing member. The packing fixing member, the third packing, the second packing and the first packing are sequentially filled from one end of the reaction unit (2) near the outlet pipe (8) to the other end near the inlet pipe (7); wherein, the second packing includes at least a catalyst. C3) In step S2, during the cyclic reaction, the mixing vessel (1) is heated to 60℃~80℃; C4) In step S2, during the cyclic reaction, the reaction unit (2) is heated to 120℃~160℃; C5) In step S2, during the cyclic reaction, the flow rate is 4 mL / min ~ 6 mL / min; C6) In step S3, the reaction solution is circulated once every certain period of time; In step S3 (C7), the central control sampling determines the reaction conversion rate and detects the pressure at the outlet of pump (13).

7. The method for preparing sodium 3,3',4,4'-biphenyltetracarboxylate according to claim 6, characterized in that, The method further includes one or more of the following features: C21) The first packing material is a glass ball with a diameter of 0.5~2mm and a length of 90mm~250mm. C22) The length of the second packing is 90 mm to 250 mm; C23) The catalyst is a Pd / C supported catalyst; the second packing is a mixture of Pd / C supported catalyst, glass beads and diatomaceous earth; C24) The catalyst has a packing volume of 0.5 cm³. 3 ~1.5 cm 3 ; C25) The third filler includes glass beads with a diameter of 0.5~2mm; (C26) The length of the third packing is 90 mm to 250 mm; C27) The packing fixing component is a steel wire mesh.

8. The method for preparing sodium 3,3',4,4'-biphenyltetracarboxylate according to claim 7, characterized in that, The method further includes one or more of the following features: C231) The Pd / C supported catalyst is (5%-10%) Pd / C supported catalyst; The packing volume of the Pd / C supported catalyst (C232) is 0.5 cm³. 3 ~1.5 cm 3 ; (C233) In the second filler, the filling volume of the glass spheres is 2 cm³. 3 ~4cm 3 ; (C234) In the second filler, the diameter of the glass sphere is 0.5mm~1.5mm; (C235) In the second filler, the diatomaceous earth has a filling volume of 2 cm³. 3 ~4 cm 3 .

9. The method for preparing sodium 3,3',4,4'-biphenyltetracarboxylate according to claim 1, characterized in that, The method for preparing sodium 3,3',4,4'-biphenyltetracarboxylate further includes the following steps: S4. Determine whether the reaction conversion rate is greater than the target conversion rate, and determine whether the pressure at the inlet pipe (7) is greater than the maximum pressure limit. When the pressure at the inlet pipe (7) is greater than the maximum pressure limit and the reaction conversion rate is greater than the target conversion rate, connect the qualified liquid inlet pipe (9) and the outlet pipe (8) to discharge the material to the qualified reaction vessel (3) and proceed to step S5. After the catalyst is washed, proceed to step S1 or end. When the pressure at the inlet pipe (7) is greater than the maximum pressure limit and the reaction conversion rate is less than the target conversion rate, the reaction liquid in the reaction unit (2) is drained into the mixing tank (1) and the process proceeds to step S5. After the catalyst is washed, the process proceeds to step S2. When the pressure at the inlet pipe (7) is less than the maximum pressure limit and the reaction conversion rate is greater than the target conversion rate, connect the qualified liquid inlet pipe (9) and the outlet pipe (8) to discharge the material to the qualified reaction vessel (3) and proceed to step S1 or end. When the pressure at the inlet pipe (7) is less than the maximum pressure limit and the reaction conversion rate is less than the target conversion rate, proceed to step S3; S5. Add washing liquid to the washing liquid tank (4), connect the outlet pipe (8) to the first washing liquid pipe (10), and connect the inlet pipe (7) to the second washing liquid pipe (11) so that the washing liquid enters the reaction unit (2) to wash the catalyst.

10. The method for preparing sodium 3,3',4,4'-biphenyltetracarboxylate according to claim 9, characterized in that, It also includes one or more of the following features: D1) In step S4, the target conversion rate is 95%; D2) In step S4, the maximum pressure limit is 0.6 MPa; D3) In step S5, the washing solution is selected from one or more of methanol, nitric acid aqueous solution and water.

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