CN-117504754-B - Synthesis system and method of high-purity N, N-dimethylformamide

CN117504754BCN 117504754 BCN117504754 BCN 117504754BCN-117504754-B

Abstract

The invention relates to the field of N, N-dimethylformamide, in particular to a system and a method for synthesizing high-purity N, N-dimethylformamide, which comprise a fixed bed reactor, wherein a cooling pipe is fixedly connected in the fixed bed reactor, a connecting pipe is connected in the cooling pipe, an air pump is fixedly connected at one end of the connecting pipe, which is far away from the cooling pipe, when the fixed bed reactor works, the temperature in the fixed bed reactor can continuously rise, then when the temperature rises to 400 ℃, a first control valve on a water inlet pipe is opened, cold water is injected into the cooling pipe from the water inlet pipe, then the first control valve is closed, and at the moment, the cooling pipe absorbs heat in the fixed bed reactor due to the cold water, so that the effect of cooling the inside of the fixed bed reactor is achieved, and the problems of local overheating and coking of a catalyst, increase of side reactions and reduction of the catalyst utilization rate due to overhigh temperature in the reactor are reduced.

Inventors

ZHAO CHENGCHENG
TIAN JIAMIN
WANG YUBIN
WANG HANZHI
XIA JIAYONG

Assignees

安徽金禾实业股份有限公司

Dates

Publication Date: 20260508
Application Date: 20230927

Claims (7)

1. The synthesis system of the high-purity N, N-dimethylformamide is characterized by comprising a fixed bed reactor (1), wherein a cooling pipe (5) is connected in the fixed bed reactor (1), the cooling pipe (5) is connected with an air pump (2), a piston (6) is connected in a sliding manner in the cooling pipe (5), a first water outlet pipe (9) and a water inlet pipe (7) are connected in the fixed bed reactor (1), and a first control valve (4) is fixedly arranged on each of the first water outlet pipe (9) and the water inlet pipe (7); The cooling device is characterized in that a U-shaped pipe (18) is communicated in the cooling pipe (5), an air outlet pipe (19) is connected in the cooling pipe (5), a first electromagnetic valve is fixedly arranged on the air outlet pipe (19), one side, close to the air pump (2), of the piston (6) is connected with an elastic rope (20), and one end, far away from the piston (6), of the elastic rope (20) is fixedly connected with the inner wall of the cooling pipe (5); The inside of the cooling pipe (5) is communicated with the guide pipe (10), a fixed plate (11) is fixedly connected to the inner wall of the cooling pipe (5), a rotating shaft (12) is rotatably connected to one side, close to the piston (6), of the fixed plate (11), and a plurality of stirring blades (13) are fixedly connected to the rotating shaft (12); The cooling pipe (5) is internally communicated with a connecting pipe (3), one end, away from the cooling pipe (5), of the connecting pipe (3) is fixedly connected with an air pump (2), a second control valve (8) is fixedly installed on the connecting pipe (3), and a guide pipe (10) is communicated with the connecting pipe (3).
2. The synthesis system of high-purity N, N-dimethylformamide as claimed in claim 1, wherein the bending part of the U-shaped pipe (18) is communicated with a second water outlet pipe (21), and a second electromagnetic valve (26) is fixedly connected to the second water outlet pipe (21).
3. The synthesis system of high-purity N, N-dimethylformamide as claimed in claim 1, wherein a plurality of stirring blades (13) are fixedly connected with connecting wires (14) respectively, and one end, far away from the stirring blades (13), of each connecting wire (14) is fixedly connected with a ball (15).
4. The synthesis system of high-purity N, N-dimethylformamide as set forth in claim 1, wherein the cooling tube (5) is fixedly connected with a first magnet (16) at an inner wall corresponding to the stirring blades (13), a plurality of the stirring blades are fixedly connected with second magnets (17), when the second magnets (17) move to the positions of the first magnets (16), one ends of the second magnets (17) close to the first magnets (16) attract the first magnets, and one ends of the second magnets (17) far away from the first magnets (16) repel the second magnets.
5. The synthesis system of high-purity N, N-dimethylformamide according to claim 1, wherein one end of the first water outlet pipe (9) far away from the cooling pipe (5) is communicated with a recovery box (24), one side of the recovery box (24) is fixedly connected with the fixed bed reactor (1), a drawer (25) is slidably connected in the recovery box (24), a sleeve (22) is sleeved on the surface of the cooling pipe (5), a heat conducting pipe (23) is communicated in the sleeve (22), and the other end of the heat conducting pipe (23) is communicated with the recovery box (24).
6. A method for synthesizing high-purity N, N-dimethylformamide, which is suitable for the synthesis system of high-purity N, N-dimethylformamide according to any one of claims 1 to 5, and is characterized by comprising the steps of: (1) Dimethylamine and CO are selected as raw materials, then CO is introduced into a fixed bed reactor, and dimethylamine is placed into the fixed bed reactor (1) for reaction; (2) Adding a composite catalyst into a reaction tube of the fixed bed reactor (1) to react with raw materials, wherein the reaction pressure is 1.2-8.4 MPa, and when the temperature in the fixed bed reactor (1) is too high, cooling the inside of the fixed bed reactor (1) by adding water into a cooling tube (5); (3) Waiting for raw materials to synthesize N, N-dimethylformamide in a fixed bed reactor (1) under the conditions of high temperature and catalyst reaction.
7. The method for synthesizing high-purity N, N-dimethylformamide as claimed in claim 6, wherein the specific step of cooling the inside of the fixed bed reactor (1) by adding water into the cooling tube (5) is as follows: (1) Opening a first control valve (4) on the water inlet pipe (7), injecting cold water from the water inlet pipe (7) into the cooling pipe, and then closing the first control valve (4) on the water inlet pipe (7); (2) When the temperature of the water is constant, a first control valve (4) on a first water outlet pipe (9) is opened, so that the water is discharged from the first water outlet pipe (9), an air pump (2) is started, the air pump (2) injects air into a connecting pipe (3), the air enters a cooling pipe (5) to push a piston (6), and the piston (6) pushes all the water in the cooling pipe (5) out of the first water outlet pipe (9); When the cooling pipe is filled with water, the water flows into the communicated U-shaped pipe (18), the air pump (2) continuously injects air into the cooling pipe (5), the air pushes the piston (6), the piston (6) can push the cooling pipe (5) and the water in the U-shaped pipe (18) to flow, when the piston (6) cannot be pushed, the first electromagnetic valve on the air outlet pipe (19) is automatically opened, air is discharged from the air outlet pipe (19), the elastic rope (20) pulls the piston (6) to reset, when the piston (6) moves to the rear of the air outlet pipe (19), the first electromagnetic valve is closed, the air continues to push the piston (6), and at the moment, the piston (6) pushes the water to flow back and forth in the cooling pipe (5) and the U-shaped pipe (18); When the air pump (2) injects air into the piston (6), a part of air enters the guide pipe (10), the air in the guide pipe (10) enters the water of the cooling pipe (5), the water flow impacts the stirring blades (13), the stirring blades (13) stir the water of the cooling pipe (5), meanwhile, the air sprayed out of the guide pipe (10) can apply an acting force to the liquid at one end of the U-shaped pipe (18) close to the stirring blades (13) so as to promote the water flow in the U-shaped pipe (18); when the stirring blade (13) rotates, the connecting wire (14) drives the ball (15) to rotate, the ball (15) stirs water, the stirring blade (13) rotates anticlockwise under the impact of water flow, when the second magnet (17) does not pass through the first magnet (16), the first magnet (16) and the second magnet (17) are attracted, when the second magnet (17) passes through the first magnet (16), the first magnet (16) and the second magnet (17) repel, and the rotation speed of the stirring blade (13) is improved through the repulsive force and the attractive force of the first magnet (16) and the second magnet (17); When the water in U type pipe (18) is discharged, take away the sealing plug on second outlet pipe (21), the water can be discharged in second outlet pipe (21) this moment, absorb the heat of fixed bed reactor (1) through sleeve (22), make the heat enter into retrieve in box (24) through heat pipe (23), dry other things in retrieving box (24) this moment, play the effect of retrieving the heat, when the water in cooling tube (5) is discharged, water enters into drawer (25) from first outlet pipe (9) and is retrieved by drawer (25).

Description

Synthesis system and method of high-purity N, N-dimethylformamide Technical Field The invention relates to the technical field of N, N-dimethylformamide synthesis, and relates to a system and a method for synthesizing high-purity N, N-dimethylformamide. Background Existing N, N-dimethylformamide synthesis systems are formed from a combination of a plurality of instruments, the most important of which is a fixed bed reactor in which operation under high temperature conditions is required. One chinese patent with publication No. CN112898174a discloses a process for the preparation of N, N-dimethylformamide, which employs dimethylamine and carbon monoxide (CO) as reactants, and prepares DMF by CO-inserted carbonylation under catalytic action. The reaction conditions are as follows, the reaction is carried out in a fixed bed reactor, and the reaction pressure is 1.0-8.0 MPa. When N, N-dimethylformamide is synthesized in a fixed bed reactor, a plurality of reactors are required to be connected in parallel in the fixed bed reactor, a catalyst is required to be filled in a pipe for reaction, the temperature in the reactor is required to be controlled in time, and when the temperature in the reactor is too high, the problems of local overheating and coking of the catalyst, increased side reactions, reduced catalyst utilization rate and the like can occur. Disclosure of Invention Aiming at the technical problems in the prior art, the invention aims to provide a synthesis system and a method of high-purity N, N-dimethylformamide, which can enable a fixed bed reactor to be rapidly cooled. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: the synthesis system of the high-purity N, N-dimethylformamide comprises a fixed bed reactor, wherein a cooling pipe is connected in the fixed bed reactor, the cooling pipe is connected with an air pump, a piston is connected in a sliding manner in the cooling pipe, a first water outlet pipe and a water inlet pipe are connected in the fixed bed reactor, and a first control valve is fixedly arranged on each of the first water outlet pipe and the water inlet pipe. Further, the U-shaped tube is connected in the cooling tube, the air outlet tube is connected in the cooling tube, a first electromagnetic valve is fixedly arranged on the air outlet tube, one side, close to the air pump, of the piston is connected with an elastic rope, and one end, far away from the piston, of the elastic rope is fixedly connected with the inner wall of the cooling tube. During operation, through pouring water into the cooling tube, water can flow into U type intraductal this moment, U type pipe can increase the heat absorption rate to the fixed bed reactor in, water in the cooling tube is in not full state simultaneously, afterwards use the air pump to continuously pour into gas in the cooling tube, make gas promote the piston, the piston can promote the water in cooling tube 5 and the U type intraductal this moment, when the piston can't be promoted, first solenoid valve on the outlet duct can be opened voluntarily, the air can be discharged from the outlet duct this moment, afterwards, the elastic rope can pull the piston and reset, then after the piston moves to the outlet duct rear, first solenoid valve is closed, gas continues to promote the piston, this moment the piston can make a round trip to promote water and flow in cooling tube and U type intraductal, the water has been played and has been flowed, thereby strengthen the heat absorption effect of water in to the fixed bed reactor 1. Further, the bending part of the U-shaped pipe provided by the invention is communicated with a second water outlet pipe, and the second water outlet pipe is fixedly connected with a second electromagnetic valve. Further, the cooling pipe is internally communicated with the guide pipe, the inner wall of the cooling pipe is fixedly connected with a fixing plate, one side, close to the piston, of the fixing plate is rotatably connected with a rotating shaft, and the rotating shaft is fixedly connected with a plurality of stirring blades. Further, a connecting pipe is connected in the cooling pipe, an air pump is fixedly connected to one end, far away from the cooling pipe, of the connecting pipe, a second control valve is fixedly installed on the connecting pipe, and a guide pipe is communicated with the connecting pipe. When the air pump injects air into the piston, because the pressure of pushing the piston is adopted, a part of air enters the guide pipe, at the moment, the air in the guide pipe can enter the water of the cooling pipe, so that water flows impact the stirring blades, at the moment, the stirring blades can stir the water of the cooling pipe, the water flow stirring can improve the heat absorption effect in the fixed bed reactor, the temperature equalizing effect of the water is improved, meanwhile, the air sprayed out of the guide pipe can apply acting fo