CN117003626B

CN117003626B - Reflux device for synthesizing o-methoxy benzaldehyde based on dimethyl sulfate

Info

Publication number: CN117003626B
Application number: CN202310989900.2A
Authority: CN
Inventors: 陈鑫; 李将; 刘肖晖
Original assignee: Zhejiang Hongda Chemicals Co ltd
Current assignee: Zhejiang Hongda Chemicals Co ltd
Priority date: 2023-08-07
Filing date: 2023-08-07
Publication date: 2024-04-23
Anticipated expiration: 2043-08-07
Also published as: CN117003626A

Abstract

The invention discloses a method for synthesizing o-methoxy benzaldehyde based on dimethyl sulfate, which comprises the following steps: adding 10% sodium hydroxide solution into a four-mouth bottle reaction container, stirring, adding salicylaldehyde, dropwise adding into the four-mouth bottle, adding a catalyst after the dropwise adding is finished, continuously stirring, heating to 90 ℃, dropwise adding dimethyl sulfate, controlling the reaction temperature to be lower than 101 ℃, dropwise adding as soon as possible, performing heat preservation reflux after the dropwise adding is finished, and controlling the total duration from the beginning of dropwise adding to the end of heat preservation reflux to be 3 hours; after the heat preservation is finished, regulating the PH of the system to 4-5 by sulfuric acid, pouring out materials, and standing for a certain time at a certain temperature to perform layering; separating an upper oil phase for subsequent washing treatment, and a lower water phase for subsequent synthesis treatment; the method has the advantages of few raw material types, convenient operation, simple requirements on preparation equipment and easy purchase and preparation.

Description

Reflux device for synthesizing o-methoxy benzaldehyde based on dimethyl sulfate

Technical Field

The invention relates to the field of preparation of o-methoxy benzaldehyde, in particular to a reflux device for synthesizing o-methoxy benzaldehyde based on dimethyl sulfate.

Background

O-methoxy benzaldehyde is mainly used as an organic synthesis intermediate, and is used for producing perfume, medicines and the like, so that a lot of help is provided for life and health of people; o-methoxy benzaldehyde is a toxic substance and is harmful to human body, and the raw materials for production are toxic; thus, more or less pollution is caused when o-methoxybenzaldehyde is used;

In the existing chemical preparation method of o-methoxy benzaldehyde, the preparation method is complex and the yield is low; in the preparation process, a plurality of chemical raw materials are used, and the chemical raw materials are used in a large quantity, so that the preparation method is harmful to human bodies, can pollute the environment, and has the unavoidable phenomenon of changing the environment into economic benefits; therefore, the invention provides a reflux device for synthesizing o-methoxy benzaldehyde based on dimethyl sulfate.

Disclosure of Invention

The invention aims to provide a reflux device for synthesizing o-methoxy benzaldehyde based on dimethyl sulfate, which aims to solve the problems in the background technology.

In order to achieve the above purpose, the present invention provides the following technical solutions:

a method for synthesizing o-methoxy benzaldehyde based on dimethyl sulfate, which comprises the following steps:

S1: placing dilute sodium hydroxide solution into a reaction container, adding salicylaldehyde and a catalyst, stirring and heating to more than 85 ℃;

S2: controlling the reaction temperature to be between 85 and 101 ℃, dropwise adding dimethyl sulfate, finishing the dropwise adding, carrying out heat preservation reflux, and enabling the total time period of dropwise adding to the end of the reflux to exceed 2 hours;

s3: after the heat preservation is finished, regulating the pH value of the system to be 4-5 by sulfuric acid, pouring out materials, and standing until layering under the heat preservation of more than 80 ℃; separating out an upper oil phase for washing; and washing to obtain the o-methoxy benzaldehyde finished product.

Preferably, in the step S1, the temperature is raised to 90 ℃; in the step S2, the reaction temperature is controlled to be between 90 and 101 ℃.

Preferably, the catalyst is any one or a mixture of more than two of chain polyethylene glycol, chain polyethylene glycol alkyl ether, benzyl triethyl ammonium chloride (TEBA), tetrabutylammonium bromide (TBAB), tetrabutylammonium chloride, tetrabutylammonium bisulfate, trioctylmethyl ammonium chloride, dodecyl trimethyl ammonium chloride, tetradecyl trimethyl ammonium chloride and the like.

Preferably, the washing step in step S3 further comprises step S3-1, step S3-2 and step S3-3:

S3-1: pouring 5% sodium hydroxide solution or secondary washing water synthesized in the previous time into the oil phase, heating to 60-70 ℃, stirring, washing, standing for layering, discharging the oil phase, and collecting the water phase as primary washing water for later use;

S3-2: pouring 5% sodium hydroxide solution into the oil phase discharged in the step S4 again, heating to 60-70 ℃, stirring, washing, standing for layering, discharging the oil phase, and collecting the water phase as secondary washing water for later use;

S3-3: and (3) pouring clear water into the oil phase discharged in the step (S3-2), heating to 60-70 ℃, stirring, washing, standing for layering, discharging the oil phase, and collecting the water phase as three times of washing water for standby.

Preferably, the dilute sodium hydroxide solution in the step S1 is 10% sodium hydroxide solution;

The primary washing water in S3-1 and the tertiary washing water in S3-3 are used for preparing 10% sodium hydroxide solution;

The secondary wash water in S3-2 is used for washing in S3-1 or for formulating a 10% sodium hydroxide solution.

Preferably, after the step S3, the method further includes:

Step S4: step S3, a lower water phase in the step; adding 32% sodium hydroxide solution; heating to 102 ℃, refluxing for at least 30 minutes to decompose dimethyl sulfate, and then converting into distillation;

Step S5: in the distillation process, dropwise adding sodium hydroxide solution to control the pH value to be more than or equal to 9; distilled water enters sewage, or another fraction is methanol;

Step S6: concentrating until solid is separated out, and performing hot filtration after salt is separated out; the solid is wet sodium sulfate, and the filtrate is distilled continuously until the sodium sulfate is obtained after the distillation.

The method for synthesizing o-methoxy benzaldehyde based on dimethyl sulfate adopts a reflux device, wherein the steps S1-S5 are realized through the reflux device; the reflux device comprises a reflux container, and a condensing device is arranged on the upper side of the reflux container; the bottom of the condensing device is provided with a plurality of condensing pipes which can be inserted into grooves formed in the reflux container; the upper surface of the bottom of the condensing device is slidably connected with an air quantity control structure, and the air quantity control structure is used for covering the top of the condensing tube, so that the air quantity entering the condensing tube is controlled, and the reflux cooling speed of reactants is controlled.

Preferably, a fan is arranged in the condensing device, and the fan is fixedly connected with the driving device; the fan comprises two layers of fan blades with different diameters; one layer of fan blade drives the inside of the condensing device to rotate, and the other layer of fan blade transmits air quantity, so that the reflux container is cooled more uniformly.

The sodium hydroxide solution recycling system used in the method for synthesizing the o-methoxy benzaldehyde based on dimethyl sulfate comprises a washing container for preparing washing water; the washing container comprises a first washing container, a second washing container and a third washing container which are respectively used for preparing primary washing water, secondary washing water and tertiary washing water; the washing water can be conveyed into a sodium hydroxide solution preparation device to prepare 10% sodium hydroxide solution, and the conveying capacity of the washing water is controlled through a valve; wherein the secondary washing water can also be conveyed to a washing container for preparing the primary washing water; and conveying the recycled washing water to a sodium sulfate preparation area to prepare sodium sulfate solid.

Preferably, the sodium sulfate solid can be conveyed to a sodium sulfate purification zone, and sodium hydroxide solution washing water in a washing container is conveyed to the sodium sulfate purification zone, the pH value is kept neutral, and the sodium sulfate solid is evaporated and crystallized for purification.

Compared with the prior art, the invention has the beneficial effects that:

The method has the advantages of few raw material types, convenient operation and simple requirements on preparation equipment; the raw materials used are salicylaldehyde, dimethyl sulfate, a catalyst and sodium hydroxide, so that the raw materials are few in variety and easy to purchase and prepare; the oil phase generated in the preparation process can be repeatedly used after being washed, so that pollution is reduced, and the environmental protection effect is good; the water phase obtained by primary washing can be used for preparing a sodium hydroxide solution raw material, the water phase obtained by secondary washing can be directly used as a washing stock solution for primary washing, clear water is added into the water phase obtained by tertiary washing, and the obtained water phase can be used for preparing the sodium hydroxide solution raw material; the washing water is repeatedly used for a plurality of times, so that the environment is protected, and the production cost is reduced; the produced sodium sulfate can be sold, and has certain economic benefit.

Drawings

FIG. 1 is a schematic view of the overall structure of a reflow apparatus according to the present invention;

FIG. 2 is a schematic view of the structure of the reflux vessel of the present invention;

FIG. 3 is a schematic view of the structure of the condensing unit of the present invention;

FIG. 4 is a schematic cross-sectional view of the condensing unit of the present invention at the top;

FIG. 5 is a schematic plan view of a stationary barrel of the present invention;

FIG. 6 is a schematic view of the structure of the condenser tube of the present invention;

FIG. 7 is a schematic view of the structure of the inner unfolding part of the fixing barrel for blocking cloth;

FIG. 8 is a schematic view of the structure at the top of the condensing unit of the present invention;

FIG. 9 is a flow chart of the recycling system of the present invention.

In the figure: 1a reflux device, 11 a reflux container, 111 an annular groove, 112 a liquid outlet, 113 a liquid inlet, 12a condensing device, 13 a fan, 21 a condensing tube, 22 a fixed cylinder, 222 a moving groove, 223 a blocking cloth, 224 a blocking plate, 23 a rotating ring, 24 a fixed ring, 25 an air volume control structure 25, 31 a connecting part, 311 an anti-drop ring, 32 a condensing part and 100 valves.

Detailed Description

Example 1:

250 g of 10% sodium hydroxide solution is put into a four-mouth bottle to be stirred, 50 g of salicylaldehyde is added dropwise, then 0.25 g of chain polyethylene glycol is added, stirring is continued and the temperature is raised to 90 ℃; then 56.8 g of dimethyl sulfate is added dropwise, the reaction temperature is controlled below 101 ℃, then the heat preservation reflux is carried out, and the total time length from the beginning of the dropwise addition to the end of the heat preservation reflux is controlled to be 3 hours; adjusting the pH of the system to 4-5 with sulfuric acid, pouring out the materials, standing for 30 minutes at 80 ℃ for layering; separating an upper oil phase for subsequent washing treatment, and a lower water phase for subsequent synthesis treatment;

washing the oil phase, adding 50 g of 5% sodium hydroxide solution into the oil phase, heating to 60-70 ℃, stirring, washing, standing, layering, discharging the oil phase, and collecting the water phase as primary washing water;

Adding 50 g of sodium hydroxide solution into the oil phase again, heating to 60-70 ℃, stirring and washing, standing for layering, discharging the oil phase, and collecting the water phase as secondary washing water;

Adding 50 g of clear water into the oil phase again, heating to 60-70 ℃, stirring, washing, standing for layering, discharging an oil phase, and collecting the water phase as three times of washing water;

putting about 240 g of the synthesized water phase into a four-mouth bottle, adding 37.5 g of 32% sodium hydroxide solution, heating and refluxing for 30 minutes through a reflux device 1 to decompose dimethyl sulfate, and then converting into distillation;

In the distillation process, the pH value is always kept to be equal to or larger than 9; distilled water enters sewage or is rectified to recycle methanol; concentrating to a certain extent, starting to precipitate solid, and performing hot filtration after the precipitation amount reaches a certain extent; the solid is sodium sulfate wet product, and the filtrate is distilled continuously until the filtrate is evaporated to dryness; the yield of the o-methoxybenzaldehyde is 86.4% and the purity is 99.1%.

Example 2:

On the basis of the example 1, 250 g of 10% sodium hydroxide solution prepared from primary washing water is put into a four-mouth bottle to be stirred, 50 g of salicylaldehyde is added dropwise, 0.25 g of chain polyethylene glycol is added, stirring is continued, and the temperature is raised to 90 ℃; then 56.8 g of dimethyl sulfate is added dropwise, the reaction temperature is controlled below 101 ℃, then the heat preservation reflux is carried out, and the total time length from the beginning of the dropwise addition to the end of the heat preservation reflux is controlled to be 3 hours; adjusting the pH of the system to 4-5 with sulfuric acid, pouring out the materials, standing for 30 minutes at 80 ℃ for layering; separating an upper oil phase for subsequent washing treatment, and a lower water phase for subsequent synthesis treatment;

the oil phase was subjected to the same washing treatment as in example 1;

In the distillation process, the pH value is always kept to be equal to or larger than 9; distilled water enters sewage or is rectified to recycle methanol; concentrating to a certain extent, starting to precipitate solid, and performing hot filtration after the precipitation amount reaches a certain extent; the solid is sodium sulfate wet product, and the filtrate is distilled continuously until the filtrate is evaporated to dryness; the yield of o-methoxybenzaldehyde was 93.3% and the purity was 98.6%.

Example 3:

On the basis of the example 1, 250 g of 10% sodium hydroxide solution prepared from three times of washing water is placed into a four-mouth bottle to be stirred, 50 g of salicylaldehyde is dropwise added, 0.25 g of chain polyethylene glycol is added, stirring is continued, and the temperature is raised to 90 ℃; then 56.8 g of dimethyl sulfate is added dropwise, the reaction temperature is controlled below 101 ℃, then the heat preservation reflux is carried out, and the total time length from the beginning of the dropwise addition to the end of the heat preservation reflux is controlled to be 3 hours; adjusting the pH of the system to 4-5 with sulfuric acid, pouring out the materials, standing for 30 minutes at 80 ℃ for layering; separating an upper oil phase for subsequent washing treatment, and a lower water phase for subsequent synthesis treatment;

the oil phase was subjected to the same washing treatment as in example 1;

in the distillation process, the pH value is always kept to be equal to or larger than 9; distilled water enters sewage or is rectified to recycle methanol; concentrating to a certain extent, starting to precipitate solid, and performing hot filtration after the precipitation amount reaches a certain extent; the solid is sodium sulfate wet product, and the filtrate is distilled continuously until the filtrate is evaporated to dryness; the yield of o-methoxybenzaldehyde was 91.2% and the purity was 98.5%.

Example 4:

placing 250 g of 10% sodium hydroxide solution prepared by using the primary washing water in the example 2 into a four-mouth bottle, stirring, dripping 50g of salicylaldehyde, adding 0.25 g of chain polyethylene glycol, continuously stirring, and heating to 90 ℃; then 56.8 g of dimethyl sulfate is added dropwise, the reaction temperature is controlled below 101 ℃, then the heat preservation reflux is carried out, and the total time length from the beginning of the dropwise addition to the end of the heat preservation reflux is controlled to be 3 hours; adjusting the pH of the system to 4-5 with sulfuric acid, pouring out the materials, standing for 30 minutes at 80 ℃ for layering; separating an upper oil phase for subsequent washing treatment, and a lower water phase for subsequent synthesis treatment;

the oil phase was subjected to the same washing treatment as in example 1;

In the distillation process, the pH value is always kept to be equal to or larger than 9; distilled water enters sewage or is rectified to recycle methanol; concentrating to a certain extent, starting to precipitate solid, and performing hot filtration after the precipitation amount reaches a certain extent; the solid is sodium sulfate wet product, and the filtrate is distilled continuously until the filtrate is evaporated to dryness; the yield of o-methoxybenzaldehyde was 92.2% and the purity was 98.8%.

Example 5:

Placing the three-time washing water in the example 2 for preparing 250 g of 10% sodium hydroxide solution into a four-mouth bottle for stirring, dropwise adding 50g of salicylaldehyde, adding 0.25 g of chain polyethylene glycol, continuously stirring and heating to 90 ℃; then 56.8 g of dimethyl sulfate is added dropwise, the reaction temperature is controlled below 101 ℃, then the heat preservation reflux is carried out, and the total time length from the beginning of the dropwise addition to the end of the heat preservation reflux is controlled to be 3 hours; adjusting the pH of the system to 4-5 with sulfuric acid, pouring out the materials, standing for 30 minutes at 80 ℃ for layering; separating an upper oil phase for subsequent washing treatment, and a lower water phase for subsequent synthesis treatment;

the oil phase was subjected to the same washing treatment as in example 1;

In the distillation process, the pH value is always kept to be equal to or larger than 9; distilled water enters sewage or is rectified to recycle methanol; concentrating to a certain extent, starting to precipitate solid, and performing hot filtration after the precipitation amount reaches a certain extent; the solid is sodium sulfate wet product, and the filtrate is distilled continuously until the filtrate is evaporated to dryness; the yield of o-methoxybenzaldehyde was 92.3% and the purity was 98.5%.

Example 6:

Placing 250 g of 10% sodium hydroxide solution prepared by using the primary washing water in the example 3 into a four-mouth bottle, stirring, dripping 50g of salicylaldehyde, adding 0.25 g of chain polyethylene glycol, continuously stirring, and heating to 90 ℃; then 56.8 g of dimethyl sulfate is added dropwise, the reaction temperature is controlled below 101 ℃, then the heat preservation reflux is carried out, and the total time length from the beginning of the dropwise addition to the end of the heat preservation reflux is controlled to be 3 hours; adjusting the pH of the system to 4-5 with sulfuric acid, pouring out the materials, standing for 30 minutes at 80 ℃ for layering; separating an upper oil phase for subsequent washing treatment, and a lower water phase for subsequent synthesis treatment;

the oil phase was subjected to the same washing treatment as in example 1;

In the distillation process, the pH value is always kept to be equal to or larger than 9; distilled water enters sewage or is rectified to recycle methanol; concentrating to a certain extent, starting to precipitate solid, and performing hot filtration after the precipitation amount reaches a certain extent; the solid is sodium sulfate wet product, and the filtrate is distilled continuously until the filtrate is evaporated to dryness; the yield of o-methoxybenzaldehyde was 91.9% and the purity was 98.7%.

Example 7:

Placing the three-time washing water in the example 3 into a four-mouth bottle for stirring to prepare 250 g of 10% sodium hydroxide solution, dropwise adding 50g of salicylaldehyde, adding 0.25 g of chain polyethylene glycol, continuously stirring and heating to 90 ℃; then 56.8 g of dimethyl sulfate is added dropwise, the reaction temperature is controlled below 101 ℃, then the heat preservation reflux is carried out, and the total time length from the beginning of the dropwise addition to the end of the heat preservation reflux is controlled to be 3 hours; adjusting the pH of the system to 4-5 with sulfuric acid, pouring out the materials, standing for 30 minutes at 80 ℃ for layering; separating an upper oil phase for subsequent washing treatment, and a lower water phase for subsequent synthesis treatment;

the oil phase was subjected to the same washing treatment as in example 1;

in the distillation process, the pH value is always kept to be equal to or larger than 9; distilled water enters sewage or is rectified to recycle methanol; concentrating to a certain extent, starting to precipitate solid, and performing hot filtration after the precipitation amount reaches a certain extent; the solid is sodium sulfate wet product, and the filtrate is distilled continuously until the filtrate is evaporated to dryness; the yield of o-methoxybenzaldehyde was 92.7% and the purity was 98.9%.

The sodium hydroxide solution in example 2 and example 3 was formulated for the primary wash water and the tertiary wash water in example 1, and was called primary wash water; the wash water produced in example 2 and example 3 is referred to as second generation wash water; examples 4 and 5 were formulated with the primary wash water and the tertiary wash water in example 2, and examples 6 and 7 were formulated with the primary wash water and the tertiary wash water in example 3; from the yields and purities of examples 2 to 7, it was found that higher yields and purities were obtained both with the sodium hydroxide solutions of examples 2 and 3 formulated with the primary wash water and with the sodium hydroxide solutions of examples 4 to 7 formulated with the secondary wash water.

Example 8

The chain polyethylene glycol of example 1 was replaced with a chain polyethylene glycol alkyl ether, and the remainder was the same as in example 1, except that the yield of o-methoxybenzaldehyde was 91.3% and the purity was 97.5%.

Example 9

The linear polyethylene glycol of example 1 was replaced with tetrabutylammonium chloride, and the rest was the same as in example 1, the yield of o-methoxybenzaldehyde was 89.4% and the purity was 96.1%.

Example 10

The chain polyethylene glycol of example 1 was replaced with dodecyltrimethylammonium chloride, and the remainder was the same as in example 1, wherein the yield of o-methoxybenzaldehyde was 92.2% and the purity was 94.5%.

Example 8-example 10 is the effect of different catalysts on the yield of o-methoxybenzaldehyde.

Example 11

Reflux unit 1 was suitable for use in the reflux step of the reaction of example 1; as shown in fig. 1 to 8, the reflux apparatus 1 includes a reflux vessel 11, a condensing apparatus 12, and a blower 13; a plurality of condensation pipes 21 are arranged at the bottom of the condensation device 12, the condensation pipes 21 are annularly distributed at the bottom of the condensation device 12, the condensation pipes 21 can be inserted into annular grooves 111 formed in the top of the reflux container 11, and the number of the annular grooves 111 is multiple; the fan 13 is positioned at the upper side inside the condensing device 12; the reflux container 11 is a main body part consisting of a column body and a hemispherical shape, wherein the bottom of the column body is fixedly connected with a liquid outlet 112, and the upper side of the column body is fixedly connected with a liquid inlet 113;

The condensing device 12 comprises a fixed cylinder 22, a rotating ring 23, a fixed ring 24 and a fixed frame; the condensing tube 21 is connected with the bottom of the fixed cylinder 22 through bolts; the outer wall of the top of the fixed cylinder 22 is connected with a rotating ring 23 through bolts; the outer wall of the rotating ring 23 is rotationally connected with the fixed ring 24; the fixed ring 24 is fixedly connected to the fixed frame;

The middle part of the fixed cylinder 22 is hollowed out from the middle part to the upper side, the middle part to the lower side of the fixed cylinder 22 is solid, and the bottom is provided with a hemispherical groove; the hemispherical groove is matched with the annular groove 111 in size; the condensing tube 21 is connected with the middle to lower part of the fixed cylinder 22 by bolts and leaks out of the hemispherical groove, so that the condensing tube 21 can be inserted into the annular groove 111; the condensation duct 21 includes a connection portion 31 and a condensation portion 32; the number of the condensation pipes 21 is plural; the bottom of the connecting part 31 is fixedly connected with the top of the condensing part 32; the outer wall of the connecting part 31 is provided with threads for being connected with the fixed cylinder 22 through bolts; the top of the connecting part 31 is fixedly connected with an anti-drop ring 311, and the diameter of the anti-drop ring 311 is larger than that of the connecting part 31, so as to prevent the condenser tube 21 from dropping off from the fixed cylinder 22; the bottom of the condensing part 32 is hemispherical, and the outer wall of the condensing part 32 is provided with air holes, so that the air is blown to the annular groove 111 from the air holes;

The middle part of the fixed cylinder 22 is a plane, and the anti-drop ring 311 is positioned on the upper side of the plane of the middle part of the fixed cylinder 22; the plane in the middle of the fixed cylinder 22 is connected with an air quantity control structure 25 in a sliding way; the air volume control structure 25 includes a pair of moving grooves 222, a pair of sliding blocks, a blocking cloth 223, a pair of traction ropes and springs; a pair of moving grooves 222 are parallel, and a sliding block is connected in a sliding manner in each moving groove 222; the blocking cloth 223 is circular when unfolded, the diameter of the circular shape is smaller than the inner wall of the fixed cylinder 22, and the circular area can cover all the condensation pipes 21; the two ends of the spring are fixedly connected to the two sides of the middle part of the fixed cylinder 22, and the main body part between the two ends of the spring is fixedly connected with the half round periphery of the barrier cloth 223 when the barrier cloth is unfolded; the blocking cloth 223 is positioned between the inner wall of the fixed cylinder 22 and the circle formed by the outermost Zhou Lengning pipe 21 when being folded, and the spring gradually changes into an arc state along with the folding of the blocking cloth 223 and is adapted to the shape of the circular periphery of half of the blocking cloth 223; the sliding block is fixedly connected with one side of the blocking cloth 223 containing the springs, and the sliding block is lower than the blocking cloth 223 and the springs; a pair of traction ropes are fixedly connected and extend to two sides through the sliding block, and finally penetrate through the fixed cylinder 22; the traction rope can be fixed on the outer wall of the fixed cylinder 22; by pulling one end of the traction rope from the outside of the fixed cylinder 22, the traction rope drives the sliding block to slide in the moving groove 222, and the sliding block drives the blocking cloth 223 to overcome the elastic movement of the spring, so that the top of the condensing tube 21 is covered by the blocking cloth 223, and the air quantity entering the condensing tube 21 is reduced; the other end of the traction rope is pulled reversely, and the sliding block moves reversely, so that the blocking cloth 223 is driven to move reversely, and finally the blocking cloth 223 is positioned at the edge of the inner wall of the fixed cylinder 22 and does not cover the top of the condensation tube 21.

The fan 13 is fixedly connected with two layers of fan blades; the fan comprises a first layer of fan blades and a second layer of fan blades, wherein the second layer of fan blades are positioned on the upper side of the first layer of fan blades, and the diameter formed by the periphery of the first layer of fan blades is smaller than the diameter formed by the periphery of the first layer of fan blades; the inner wall of the upper side of the middle part of the fixed cylinder 22 is rotationally connected with a plurality of blocking plates 224, the rotation angle of the blocking plates 224 is smaller than 90 degrees, and the rotation direction of the blocking plates 224 is consistent with the rotation direction of the fan 13; when the blocking plate 224 rotates out of the rotating groove formed in the fixed cylinder 22, the first layer of fan blades can push the baffle plate 224 to rotate, so that the fixed cylinder 22 is driven to rotate; the outer diameter of the second layer of fan blades is smaller than that of the blocking plate 224 after being opened, and the air quantity generated by the second layer of fan blades enters the condensing tube 21 through the fixed cylinder 22 and then blows to the annular groove 111, so that the reflux container 11 is cooled more uniformly.

When in use, the aqueous phase added with sodium hydroxide solution is put into the reflux container 11 from the liquid inlet 113, the blower 13 is started, the air quantity brought by the blower 13 is blown into the fixed cylinder 22 and enters the condensing tube 21, and the aqueous phase is blown into the inner wall of the annular groove 11 from the air hole of the condensing tube 21, so as to assist cooling;

In addition, one end of the traction rope can be pulled; the barrier cloth 223 in the folded state starts to move to cover the top of the condenser pipe 21, so that the air quantity can only enter part of the condenser pipe 21, and the reflux reaction rate is adjusted; after covering the appointed part, fixing the traction rope; then the blocking plate 224 is opened by rotation, and then the fan 13 is restarted, the first layer of fan blades push the blocking plate 224 to rotate, the blocking plate 224 drives the fixed cylinder 22 to rotate, and the fixed cylinder 22 drives the rotating ring 23 to rotate relative to the fixed ring 24; thereby, the partial condenser tube 21 which can enter the air volume after being covered can be cooled more uniformly by rotating.

The foregoing is only illustrative of the preferred embodiments of the present invention and is not to be construed as limiting the invention, but rather as various modifications, equivalent arrangements, improvements, etc., within the spirit and principles of the present invention.

Claims

1. Reflux unit based on dimethyl sulfate synthesizes o-methoxy benzaldehyde, its characterized in that: comprises a reflux container (11), a condensing device (12) and a fan (13); a plurality of condensing pipes (21) are arranged at the bottom of the condensing device (12), the condensing pipes (21) are annularly distributed at the bottom of the condensing device (12), the condensing pipes (21) can be inserted into annular grooves (111) formed in the top of the reflux container (11), and the number of the annular grooves (111) is multiple; the fan (13) is positioned at the upper side inside the condensing device (12); the reflux container (11) is a main body part consisting of a column body and a hemispherical shape, wherein the bottom of the column body is fixedly connected with a liquid outlet (112), and the upper side of the column body is fixedly connected with a liquid inlet (113);

The condensing device (12) comprises a fixed cylinder (22), a rotating ring (23), a fixed ring (24) and a fixed frame; the condensing pipe (21) is connected with the bottom of the fixed cylinder (22) through bolts; the outer wall of the top of the fixed cylinder (22) is connected with a rotating ring (23) through bolts; the outer wall of the rotating ring (23) is rotationally connected with the fixed ring (24); the fixed ring (24) is fixedly connected to the fixed frame;

The middle part of the fixed cylinder (22) is hollowed out from the middle part to the upper side, the middle part to the lower side of the fixed cylinder (22) is solid, and the bottom is provided with a hemispherical groove; the hemispherical groove is matched with the annular groove (111) in size; the condensing tube (21) is connected with the middle part to the lower part of the fixed cylinder (22) through bolts and leaks out of the hemispherical groove, so that the condensing tube (21) can be inserted into the annular groove (111); the condensing tube (21) comprises a connecting part (31) and a condensing part (32); the number of the condensation pipes (21) is plural; the bottom of the connecting part (31) is fixedly connected with the top of the condensing part (32); the outer wall of the connecting part (31) is provided with threads for being connected with the fixed cylinder (22) through bolts; the top of the connecting part (31) is fixedly connected with an anti-falling ring (311), and the diameter of the anti-falling ring (311) is larger than that of the connecting part (31) and is used for preventing the condenser tube (21) from falling off from the fixed cylinder (22); the bottom of the condensing part (32) is hemispherical, and an air hole is arranged on the outer wall of the condensing part (32) so that the air is blown to the annular groove (111) from the air hole;

The middle part of the fixed cylinder (22) is a plane, and the anti-drop ring (311) is positioned on the upper side of the plane of the middle part of the fixed cylinder (22); the plane in the middle of the fixed cylinder (22) is connected with an air quantity control structure (25) in a sliding way; the air quantity control structure (25) comprises a pair of moving grooves (222), a pair of sliding blocks, a blocking cloth (223), a pair of traction ropes and springs; a pair of moving grooves (222) are parallel, and a sliding block is connected in a sliding manner in each moving groove (222); the blocking cloth (223) is circular when unfolded, the diameter of the circular shape is smaller than the inner wall of the fixed cylinder (22), and the circular area can cover all the condensation pipes (21); the two ends of the spring are fixedly connected to the two sides of the middle part of the fixed cylinder (22), and the main body part between the two ends of the spring is fixedly connected with the semicircular periphery of the blocking cloth (223) when the blocking cloth is unfolded; the blocking cloth (223) is positioned between the inner wall of the fixed cylinder (22) and the circle formed by the outermost Zhou Lengning pipe (21) when being folded, and the spring is gradually changed into an arc state along with the folding of the blocking cloth (223) and is matched with the semicircular periphery shape of the blocking cloth (223); the sliding block is fixedly connected with one side of the blocking cloth (223) containing the springs, and the sliding block is lower than the blocking cloth (223) and the springs; the traction ropes are fixedly connected and penetrate through the sliding blocks and extend to two sides, and finally penetrate through the fixed cylinder (22); the traction rope can be fixed on the outer wall of the fixed cylinder (22); one end of a traction rope is pulled from the outside of the fixed cylinder (22), the traction rope drives a sliding block to slide in the moving groove (222), and the sliding block drives a blocking cloth (223) to overcome the elastic movement of a spring, so that the top of the condensing tube (21) is covered by the blocking cloth (223), and the air quantity entering the condensing tube (21) is reduced; the other end of the traction rope is pulled reversely, and the sliding block moves reversely, so that the blocking cloth (223) is driven to move reversely, and finally the blocking cloth (223) is positioned at the edge of the inner wall of the fixed cylinder (22) without covering the top of the condensing tube (21);

The fan (13) is fixedly connected with two layers of fan blades; the fan comprises a first layer of fan blades and a second layer of fan blades, wherein the second layer of fan blades are positioned on the upper side of the first layer of fan blades, and the diameter formed by the periphery of the first layer of fan blades is smaller than the diameter formed by the periphery of the first layer of fan blades; the inner wall of the upper side of the middle part of the fixed cylinder (22) is rotationally connected with a plurality of blocking plates (224), the rotation angle of the blocking plates (224) is smaller than 90 degrees, and the rotation direction of the blocking plates (224) is consistent with the rotation direction of the fan (13); when the blocking plate (224) rotates out of the rotating groove formed in the fixed cylinder (22), the first layer of fan blades can push the baffle plate (224) to rotate so as to drive the fixed cylinder (22) to rotate; the peripheral diameter formed by the second layer of fan blades is smaller than that formed by the baffle plate (224) after being opened, and the air quantity generated by the second layer of fan blades enters the condensing tube (21) through the fixed cylinder (22) and then is blown to the annular groove (111), so that the reflux container (11) is cooled more uniformly.