A vacuum reactor

Abstract

The utility model provides a vacuum reactor. Compared with the prior art, the vacuum reactor provided by the utility model, during the reaction process, the thionyl chloride vapor generated is condensed by a condenser, and then refluxed to the thionyl chloride outlet coil through a reflux pipe, and the discharge is achieved through a plurality of micropores on the outlet coil, so that the thionyl chloride can be gasified again due to the high temperature on the surface of the terephthalic acid material in the reactor, thereby avoiding energy waste. At the same time, the process of the thionyl chloride material being ejected from the small holes in different directions of the outlet coil participates in the mixing and stirring process with the terephthalic acid material, and the process of the sulfur dioxide gas and hydrogen chloride gas rising and overflowing generated by the contact reaction of the two materials also plays a role in mixing and stirring the materials. In addition, the vacuum reactor provided by the utility model eliminates the stirring paddle commonly used in the existing production reactor, thereby reducing the energy consumption of the reaction system.

Description

Technical Field

[0001] The utility model belongs to the technical field of organic synthesis, and specifically relates to a vacuum reactor, in particular to a vacuum reactor for producing terephthaloyl chloride. Background Art

[0002] As an important organic chemical raw material, terephthaloyl chloride has the chemical formula C8H4Cl2O2 and appears as a white crystalline powder. It is a monomer for synthesizing special fibers and can be used as a reinforcing agent for aramid and nylon. It can also be used to manufacture resin dyes, pigments, medicines and pesticides as an important organic chemical raw material.

[0003] At present, terephthalic acid is mainly used as a raw material to prepare terephthaloyl chloride. A more representative preparation method is to add a small amount of pyridine to terephthalic acid, and then reflux with excess thionyl chloride at 75-80°C for about 12 hours to generate terephthaloyl chloride, and then undergo a crystallization process to obtain a high-purity product with a melting point of 81-82°C. Generally, a vacuum reactor is required in the above preparation method. The vacuum reactor in the prior art is generally as follows: Figure 1 As shown, when the low-temperature thionyl chloride condensed and refluxed from the vacuum condensation reflux port on the kettle top contacts the higher-temperature terephthalic acid solution in the kettle, a portion of the refluxed thionyl chloride material does not participate in the reaction in time when it immediately contacts the high-temperature terephthalic acid liquid surface and evaporates, and circulates into the condensation reflux system again, resulting in waste of reaction materials and increased energy consumption, which is not conducive to energy saving. Utility Model Content

[0004] In view of this, the purpose of the utility model is to provide a vacuum reactor. The structure of the vacuum reactor can reduce reaction energy consumption and avoid waste of reaction materials.

[0005] To achieve this purpose, the utility model adopts the following technical solutions:

[0006] The utility model provides a vacuum reactor, which comprises:

[0007] A vacuum reactor body; a gas outlet is arranged above the vacuum reactor body, a thionyl chloride outlet coil is arranged below the inside of the vacuum reactor body, the thionyl chloride outlet coil is provided with micropores, a reflux pipe connected to the thionyl chloride outlet coil is arranged inside the vacuum reactor body, and the inlet of the reflux pipe is higher than the vacuum reactor body;

[0008] and a condenser arranged above the vacuum reactor body and connected to the vacuum reactor body; a gas inlet is arranged below the condenser, and a non-condensable gas outlet is arranged above the condenser;

[0009] The gas outlet of the vacuum reactor body is connected to the gas inlet of the condenser through a pipeline; the condenser is connected to the inlet of the reflux pipe through a pipeline.

[0010] Preferably, the pore size of the micropores is 0.8-3 mm.

[0011] Preferably, the spacing between the microholes is 4 to 8 cm.

[0012] Preferably, the micropores have a pore size of 1 to 2 mm.

[0013] Preferably, the spacing between the microholes is 5 to 6 cm.

[0014] Preferably, the ratio of the diameter of the vacuum reactor body to the length of the thionyl chloride outlet coil is 1:(8-15).

[0015] Preferably, the reflux pipe is further provided with a branch pipe.

[0016] Preferably, the outlet of the branch pipe is located inside the vacuum reactor body.

[0017] Preferably, the condenser is connected to the inlet of the reflux pipe through a U-shaped pipeline.

[0018] Preferably, the condenser is a shell and tube heat exchanger.

[0019] Preferably, a cooling circulating water inlet is provided below the shell-and-tube heat exchanger, and a cooling circulating water outlet is provided above the shell-and-tube heat exchanger.

[0020] Preferably, 60 to 150 heat exchange tube bundles are arranged inside the shell-and-tube heat exchanger.

[0021] Preferably, the diameter of the heat exchange tube bundle is 30-80 mm.

[0022] Preferably, a feed inlet and a discharge inlet are also provided below the vacuum reactor body.

[0023] Compared with the prior art, the beneficial effects of the utility model are:

[0024] The utility model provides a vacuum reactor. Compared with the prior art, the vacuum reactor provided by the utility model, during the reaction process, the thionyl chloride vapor generated is condensed by a condenser, and then refluxed to the thionyl chloride outlet coil through a reflux pipe, and the discharge is achieved through a plurality of micropores on the outlet coil, so that the thionyl chloride can be gasified again due to the high temperature on the surface of the terephthalic acid material in the reactor and wasted, thereby avoiding energy waste. At the same time, the process of the thionyl chloride material being ejected from the small holes in different directions of the outlet coil participates in the mixing and stirring process with the terephthalic acid material, and the process of the sulfur dioxide gas and hydrogen chloride gas rising and overflowing generated by the contact reaction of the two materials also plays a role in mixing and stirring the materials. In addition, the vacuum reactor provided by the utility model eliminates the stirring paddle commonly used in the existing production reactor, thereby reducing the energy consumption of the reaction system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of a vacuum reactor in the prior art;

[0026] Figure 2 Schematic diagram of the structure of the vacuum reactor involved in Example 1;

[0027] Among them, the vacuum reactor body is 14, 1 is a reflux pipe, 2 is a branch pipe, 3 is an interface of terephthalic acid solution, 4 is a thionyl chloride outlet coil, 5 is a discharge port, 6 is a gas outlet of the vacuum reactor body, 7 is a gas inlet of a condenser, 8 is a non-condensable gas outlet of the condenser, 9 is a condenser, 10 is a cooling circulating water inlet, 11 is a cooling circulating water outlet, 12 is a pipeline, and 13 is a feed port. DETAILED DESCRIPTION

[0028] The following will be combined with the embodiments of the utility model to clearly and completely describe the technical solution of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0029] Aiming at the problem of waste of reaction materials and increased energy consumption in the vacuum reactor in the prior art, the utility model provides a structural schematic diagram as shown in Figure 2 The vacuum reactor shown comprises: a vacuum reactor body 14 , and a condenser 9 which is arranged above the vacuum reactor body 14 and is connected to the vacuum reactor body 14 .

[0030] In the utility model, a gas outlet 6 is provided above the vacuum reactor body 14, and a thionyl chloride outlet coil 4 is provided below the inside of the vacuum reactor body 14. The thionyl chloride outlet coil 4 is provided with micropores, which can be used to discharge the condensed refluxed thionyl chloride to achieve contact with the high-temperature terephthalic acid material, avoid direct gasification waste again, and effectively save energy. In some embodiments of the utility model, the pore size of the micropore is 0.8 to 3 mm, preferably 1 to 2 mm; the spacing between the micropores is 4 to 8 cm, preferably 5 to 6 cm. It should be noted that the pore size of the micropore and the spacing between the micropores can be flexibly adjusted according to actual needs. At the same time, the thionyl chloride outlet coil 4 can also be flexibly adjusted according to the size and diameter of the actual vacuum reactor. The utility model preferably defines the diameter of the vacuum reactor body 14 and the length of the thionyl chloride outlet coil 4 as 1: (8 to 15), preferably 1: (9 to 12), and more preferably 1: 10. For example, in some embodiments of the present invention, the diameter of the vacuum reactor body 14 is 3.5 m, and the length of the thionyl chloride outlet coil 4 can be limited to 35 m, and then the thionyl chloride outlet coil 4 can be coiled, and the number of coiling turns is determined by the length of the thionyl chloride outlet coil 4.

[0031] In the present invention, a reflux pipe 1 connected to the thionyl chloride outlet coil 4 is provided inside the vacuum reactor body 14, and the reflux pipe 1 is used to reflux the thionyl chloride condensed and refluxed in the condenser 9 to the thionyl chloride outlet coil 4. It should be noted that the inlet of the reflux pipe 1 is preferably higher than the vacuum reactor body 14. In some embodiments of the present invention, the reflux pipe 1 is also provided with a branch pipe 2, and the outlet of the branch pipe 2 exists inside the vacuum reactor body 14, which mainly plays a role of pressure balance to prevent the vacuum system from being unstable, causing the reaction materials in the vacuum reactor body 14 to be sucked back through the thionyl chloride outlet coil 4, thereby entering the condenser 9.

[0032] In some embodiments of the present invention, a feed port 13 and a discharge port 5 are further provided below the vacuum reactor body 14 .

[0033] In the present invention, a gas inlet 7 is provided below the condenser 9, and a non-condensable gas outlet 8 is provided above the condenser 9. In some embodiments of the present invention, the condenser 9 can be selected as a shell-and-tube heat exchanger, and a heat exchange tube bundle is provided inside the shell-and-tube heat exchanger; the number of the heat exchange tube bundle can be selected as needed, such as 60 to 150 tubes, preferably 80 to 100 tubes; the diameter of the heat exchange tube bundle is preferably 30 to 80 mm, more preferably 40 to 50 mm. When the shell-and-tube heat exchanger is in working state, the thionyl chloride gas discharged from the gas outlet 6 of the vacuum reactor body 14 is transported to the tube path of the shell-and-tube heat exchanger through the gas inlet 7 of the shell-and-tube heat exchanger, and a cooling circulating water inlet 10 is provided below the shell-and-tube heat exchanger, and a cooling circulating water outlet 11 is provided above the shell-and-tube heat exchanger. The flow rate of the cooling circulating water can be selected according to actual needs.

[0034] It should be noted that the cooling circulating water directly enters the shell side of the shell-and-tube heat exchanger through the cooling circulating water inlet 10, cools the thionyl chloride gas in the tube side of the shell-and-tube heat exchanger, and condenses the thionyl chloride gas. After cooling, the cooling circulating water is discharged through the cooling circulating water outlet 11, and the generated non-condensable gas is discharged from the non-condensable gas outlet 8. At the same time, the condensed thionyl chloride liquid is transported to the reflux pipe 1 through the pipeline 12. In the utility model, the pipeline 12 is a U-shaped pipeline. It should be noted that the reason for designing it as a U-shaped pipeline is that the U-shaped pipeline can store liquid and play a liquid sealing role. The purpose of the liquid seal is that when vacuuming through the non-condensable gas outlet 8, the U-shaped pipeline liquid seal system prevents the gas inside the reactor from passing through the U-shaped pipeline.

[0035] In some specific embodiments of the present invention, phthalic acid solution and thionyl chloride are reacted as raw materials in a vacuum reactor body 14 to obtain terephthaloyl chloride as an example (in this scheme, the condenser 9 is represented by a shell and tube heat exchanger 9, and the pipeline 12 is represented by a U-shaped bend 12):

[0036] The vacuum reactor body 14 contains a terephthalic acid solution, and the upper interface thereof can be represented by 3;

[0037] The temperature inside the vacuum reactor body 14 is 100°C, and the reaction system is given a vacuum degree of 90kpa through the non-condensable gas outlet 8 of the shell-and-tube heat exchanger 9. Under this reaction condition, a part of the thionyl chloride material will volatilize without participating in the chemical reaction. The volatilized thionyl chloride enters the tube side of the shell-and-tube heat exchanger 9 through the gas outlet 6 and the gas inlet 7. The shell-and-tube heat exchanger 9 has 120 heat exchange tube bundles, and the diameter of each heat exchange tube bundle is 50mm. The shell-and-tube heat exchanger 9 is provided with a cooling circulating water inlet 10 at the bottom and a cooling circulating water outlet 11 at the top. When working, the cooling circulating water directly enters the shell side of the shell-and-tube heat exchanger 9 through the cooling circulating water inlet 10, cools the thionyl chloride gas in the tube side of the shell-and-tube heat exchanger 9, and condenses the thionyl chloride gas. After cooling, the cooling circulating water is discharged through the cooling circulating water outlet 11, and the generated non-condensable gas is discharged from the non-condensable gas outlet 8. At the same time, the condensed thionyl chloride liquid is gathered through the U-shaped bend 12, and when it is fully gathered, it refluxes into the thionyl chloride outlet coil 4 through the reflux pipe 1 and continues to enter the vacuum reactor body 14 to participate in the reaction.

[0038] In summary, compared with the prior art, the vacuum reactor provided by the utility model, during the reaction process, the thionyl chloride steam generated is condensed by the condenser 9, and then refluxed to the thionyl chloride outlet coil 4 through the reflux pipe 1, and the discharge is realized through the multiple micropores on the thionyl chloride outlet coil 4, so that the thionyl chloride can be gasified again due to the high temperature of the surface of the terephthalic acid material in the reactor, thereby avoiding energy waste. At the same time, the process of the thionyl chloride material being ejected from the small holes in different directions of the thionyl chloride outlet coil 4 participates in the mixing and stirring process with the terephthalic acid material, and the process of the sulfur dioxide gas and hydrogen chloride gas rising and overflowing generated by the contact reaction of the two materials also plays a role in mixing and stirring the materials. In addition, the vacuum reactor provided by the utility model cancels the stirring paddle commonly used in the existing production reactor, thereby reducing the energy consumption of the reaction system.

[0039] After testing, it was found that the vacuum reactor provided by the utility model was used for continuous feeding and continuous discharging, and the reaction conversion rate of terephthalic acid could reach 45-50%. The reaction conversion rate of terephthalic acid could be further improved by using the vacuum reactors in series. For example, in some embodiments of the utility model, by using four sets of the vacuum reactors in series, the reaction conversion rate of terephthalic acid could reach 99.96%.

[0040] In order to further illustrate the utility model, the following examples are used to explain the utility model in detail. The experimental raw materials used in the following examples of the utility model are all common commercial products.

[0041] Example 1

[0042] This embodiment provides a vacuum reactor, and its structural schematic diagram is as follows Figure 2As shown, including:

[0043] Vacuum reactor body 14 (diameter 3.5m), reflux pipe 1, branch pipe 2, interface 3 of terephthalic acid solution, thionyl chloride outlet coil 4 (the length of thionyl chloride outlet coil is 35m, and the number of circles is 12), discharge port 5, vacuum port or gas outlet 6 of vacuum reactor body, gas inlet 7 of condenser, non-condensable gas outlet 8 of condenser, condenser 9 (this embodiment is a shell and tube heat exchanger 9, with 120 tubes and a tube diameter of 50mm), cooling circulating water inlet 10, cooling circulating water outlet 11, pipeline 12 (this embodiment is a U-shaped bend 12), feed port 13;

[0044] Working status:

[0045] A mixed reaction material containing 0.717 kg of terephthalic acid solution, 1.08 kg of thionyl chloride and 0.0063 kg of N,N-dimethylformamide (DMF) continuously enters the interior of the vacuum reactor body 14 from the bottom through the feed port 13 at 80° C. (3 represents the interface of the terephthalic acid solution) until it reacts in the vacuum reactor body 14 for 16 hours and then is discharged from the bottom discharge port 5. In this process, a vacuum degree of 90 kPa is given to the reaction system through the non-condensable gas outlet 8. The thionyl chloride volatilized from the vacuum reactor body 14 enters the tube path of the shell-and-tube heat exchanger through the gas outlet 6 and the gas inlet 7 in turn. At the same time, the cooling circulating water is cooled at 30 mm 3 / h enters the shell side of the tube heat exchanger through the cooling circulating water inlet 10 of the tube heat exchanger to cool the thionyl chloride gas, and the cooling circulating water is discharged from the tube heat exchanger 9 through the cooling circulating water outlet 11. During the cooling process, the gaseous thionyl chloride condenses in the tube heat exchanger 9 and gathers through the U-bend 12. When it is fully gathered, it refluxes into the thionyl chloride outlet coil 4 through the reflux pipe 1, flows out from the small holes (hole diameter of 10mm, hole spacing of 50mm) of the thionyl chloride outlet coil 4, and continues to enter the vacuum reactor body 14 to participate in the reaction.

[0046] The vacuum reactor provided in this embodiment continuously feeds and discharges, and the reaction conversion rate of terephthalic acid reaches 45%. Four sets of vacuum reactors of this embodiment are connected in series in sequence to continuously feed and participate in the reaction, and the reaction conversion rate of terephthalic acid can reach 99.96%, and the final reaction product is a mixture of terephthaloyl chloride and DMF.

[0047] Compared with the vacuum reactor of the prior art (such as Figure 1Compared with the vacuum reactor provided by the utility model, its reaction energy consumption is twice that of the vacuum reactor provided by the utility model, and its reaction time is 1.5 times that of the vacuum reactor provided by the utility model. It can be seen that compared with the prior art, the vacuum reactor provided by the utility model reduces reaction energy consumption, saves resources and time.

[0048] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A vacuum reactor, characterized in that: include: A vacuum reactor body; a gas outlet is arranged above the vacuum reactor body, a thionyl chloride outlet coil is arranged below the inside of the vacuum reactor body, the thionyl chloride outlet coil is provided with micropores, a reflux pipe connected to the thionyl chloride outlet coil is arranged inside the vacuum reactor body, and the inlet of the reflux pipe is higher than the vacuum reactor body; and a condenser disposed above the vacuum reactor body and connected to the vacuum reactor body; a gas inlet is disposed below the condenser, and a non-condensable gas outlet is disposed above the condenser; The gas outlet of the vacuum reactor body is connected to the gas inlet of the condenser through a pipeline; the condenser is connected to the inlet of the reflux pipe through a pipeline.

2. The vacuum reactor according to claim 1, characterized in that: The pore size of the micropores is 0.8 to 3 mm; The spacing between the microholes is 4 to 8 cm.

3. The vacuum reactor according to claim 2, characterized in that: The micropores have a pore size of 1 to 2 mm; The spacing between the microholes is 5 to 6 cm.

4. The vacuum reactor according to claim 1 or 2, characterized in that: The ratio of the diameter of the vacuum reactor body to the length of the thionyl chloride outlet coil is 1:(8-15).

5. The vacuum reactor according to claim 1 or 2, characterized in that: The reflux pipe is also provided with a branch pipe; The outlet of the branch pipe exists inside the vacuum reactor body.

6. The vacuum reactor according to claim 1 or 2, characterized in that: The condenser is connected to the inlet of the reflux pipe through a U-shaped pipeline.

7. The vacuum reactor according to claim 1, characterized in that: The condenser is a shell and tube heat exchanger.

8. The vacuum reactor according to claim 7, characterized in that: A cooling circulating water inlet is arranged below the shell-and-tube heat exchanger, and a cooling circulating water outlet is arranged above the shell-and-tube heat exchanger.

9. The vacuum reactor according to claim 7 or 8, characterized in that: The shell-and-tube heat exchanger is provided with 60 to 150 heat exchange tube bundles inside; The diameter of the heat exchange tube bundle is 30-80 mm.

10. The vacuum reactor according to claim 1, characterized in that: A feed inlet and a discharge inlet are also provided below the vacuum reactor body.

Images