CN219051353U

CN219051353U - Improved tubular reactor and production equipment using same

Info

Publication number: CN219051353U
Application number: CN202221026236.9U
Authority: CN
Inventors: 郭庆春; 宋海文; 郭红永; 殷祖淼; 张松
Original assignee: Inner Mongolia Lange Biotechnology Co ltd; Hebei Lansheng Biotech Co ltd
Current assignee: Inner Mongolia Lange Biotechnology Co ltd; Lansheng Biotechnology Group Co ltd
Priority date: 2022-04-30
Filing date: 2022-04-30
Publication date: 2023-05-23
Anticipated expiration: 2032-04-30

Abstract

The present application relates to an improved tubular reactor and a production facility using the same. The tubular reactor comprises a reaction tube and branch tubes, wherein the reaction tube is a continuous tube or is divided into more than two sections, and the branch tubes are directly arranged on the reaction tube and/or between the reaction tubes. The production equipment comprises a tubular reactor and a kettle reactor which are sequentially connected in series.

Description

Improved tubular reactor and production equipment using same

Technical Field

The present application relates to an improved tubular reactor and a production facility using the same.

Background

In large-scale industrial production, it is difficult to maintain absolute stability of a pump by pumping a feed, thereby causing instability and unevenness of the feed, and unevenness of a reaction material may cause a series of problems such as an increase in side reactions, local thermal runaway of the reaction, and the like. Particularly, for the reaction using and producing easily-decomposable or inflammable and explosive dangerous substances, the thermal runaway of the reaction not only causes the decomposition of the easily-decomposable substances to influence the reaction progress or the yield, but also may cause more serious risks such as burning and explosion of the inflammable and explosive substances.

For example, the sulfonyl compound 4-methanesulfonyl-2, 3-disubstituted benzene is an important intermediate for the herbicide topramezone, which is generally prepared by catalytic oxidation of the corresponding 4-methylsulfanyl-2, 3-disubstituted benzene compound with an oxidizing agent of 25-30% concentration of hydrogen peroxide (see, for example, CN1300284a, etc.).

In the current industrial production, the catalytic oxidation reaction is carried out in an intermittent mode by adopting a reaction kettle, materials are accumulated in the kettle, and mass transfer and heat transfer are poor. The risk factor of the oxidizing agent hydrogen peroxide is high, and safety problems are easily caused by excessive storage in the reaction system. In addition, the reaction heat promotes an increase in reaction rate, which in turn leads to more exotherm and thus may initiate thermal runaway. The severe temperature rise due to the heat of reaction also increases the hydrogen peroxide decomposition rate, which leads to incomplete reaction.

Disclosure of Invention

The problem of thermal runaway of the reaction can be alleviated because the liquid holdup of the tubular reactor is small. Accordingly, the present inventors have attempted to produce 4-methanesulfonyl-2, 3-disubstituted benzene by performing the above catalytic oxidation reaction using a tubular reactor.

However, the present inventors found that when a conventional tubular reactor is used, the reaction exotherm is severe, a large amount of gas is generated, and the yield is unstable. In addition, the trace of the reactant by HPLC shows that the 4-methylthio-2, 3-disubstituted benzene compound as the raw material is basically reacted, but more than 30% of sulfinyl intermediate is difficult to continue the reaction, and the measures such as further prolonging the length of the reaction tube, expanding the tube diameter, filling the tube, heating the tube and the like are difficult to effectively promote the reaction to continue.

In order to solve the above problems, the present inventors have attempted to improve a tubular reactor, and found that the residual amount of sulfinyl intermediate in the material exiting from the improved tubular reactor is reduced, but the complete reaction requirement of industrial production is still not achieved. The inventors of the present application further tried to connect a tank reactor after the tubular reactor, and unexpectedly found that after the incompletely reacted materials coming out of the tubular reactor were further introduced into the tank reactor with sufficient stirring, the reaction was sufficiently carried out, and the residual amount of the sulfinyl intermediate was less than 1% after staying in the tank reactor for 0.1 to 1 hour. The present utility model has been completed based on the above findings.

In one aspect, the present utility model provides an improved tubular reactor comprising a reactor tube that is a continuous tube or is divided into more than two sections, and a branch tube that is disposed directly on the reactor tube and/or between the reactor tubes. The stay time of the materials is differentiated through the branch pipes, so that the materials with concentration differences are remixed, the materials are more uniform, and the risk of thermal runaway of reaction is reduced.

In another aspect, the present utility model provides a novel production facility comprising the improved tubular reactor described above and a tank reactor in series therewith. The production equipment can effectively solve the problems of thermal runaway and incomplete reaction.

Drawings

FIG. 1 is a schematic structural view of one embodiment of the tubular reactor of the present application.

FIG. 2 is a schematic structural view of another embodiment of the tubular reactor of the present application.

FIG. 3 is a schematic structural view of still another embodiment of the tubular reactor of the present application.

Fig. 4 is a schematic diagram showing a specific morphological structure of the branch pipe of the present application, in which fig. 4-1 is an asymmetric mouth-shaped branch pipe structure having upper and lower branches, and fig. 4-2 is a D-shaped branch pipe structure.

Fig. 5 is a schematic diagram of the structure of an embodiment of the production apparatus of the present application.

Fig. 6 is a schematic structural view of another embodiment of the production apparatus of the present application.

Reference numerals illustrate:

1. a tubular reactor; 2. a branch pipe; 3. a reaction tube; 3-1, a first-stage reaction tube; 3-2, a second section of reaction tube; 3-3, a third section of reaction tube; 3-4, a fourth section of reaction tube; 4. a kettle type reactor.

Detailed Description

The improved tubular reactor and production apparatus configurations of the present application are described in more detail below with reference to the drawings, but the present application is not limited to this particular embodiment, and any modifications and alterations within the scope of the subject application fall within the scope of the present application.

The instability of the feed pump can lead to fluctuation of the feed rate or deviation of the feed amount, and further cause uneven axial direction of materials in the tubular reactor 1, influence the stable operation of the reaction or cause adverse side reactions and the like.

The main improvement of the tubular reactor 1 is the addition of the branch pipe 2. The branch pipe 2 has the function of differentiating the residence time of the materials in the reaction pipe 3, mixing the materials with different residence time and concentration, and reducing the axial non-uniformity of the materials in the reaction pipe 3.

The position, number and form of the branches 2 may comprise a number of different solutions as long as they are able to function to vary the residence time of the material.

The branch pipe 2 may be disposed directly on the reaction tube 3 as shown in fig. 1 and 2, or may be disposed between different sections of the reaction tube 3 when the reaction tube 3 is divided into a plurality of sections as shown in fig. 3. It is also possible to provide both the reaction tubes and the reaction tube sections or to provide a portion on the reaction tubes and a portion between the reaction tube sections.

Since the axial unevenness of the material due to the unstable feeding is generally more remarkable at the position of the reaction tube 3 closer to the feed port, it is preferable to start the branch tube 2 at the position closer to the feed end, so as to avoid the adverse problems such as side reaction, thermal runaway reaction, etc. caused by the material reacting too long in the reaction tube 3 in the uneven state. In fig. 1, 2 and 3, although a structure in which the branch pipe 2 is provided in each section of the reaction tube 3 is illustrated, this does not mean that such a structure is necessary. If the materials reach good mixing effect in the front section of the reaction tube 3, the branch tubes 2 are not required in the middle and rear sections of the reaction tube 3, or the branch tubes 2 are arranged in a larger density in the front section of the reaction tube 3 than in the middle and rear sections.

The number of branch pipes 2 is reasonably determined according to factors such as equipment scale and the like. The larger the theoretical quantity, the more times the materials with different concentrations are mixed, and the better the effect of eliminating the axial unevenness is, but other factors such as equipment cost, scale and the like are also required to be considered.

The branch pipe 2 may be asymmetric in shape as shown in fig. 4-1, D-shaped as shown in fig. 4-2, rectangular pipe, arc pipe, etc. The asymmetric shape of the mouth refers to that when the branch pipe is vertically or horizontally branched, the branch pipe is vertically asymmetric or horizontally asymmetric. For example, as shown in fig. 4-1, the upper branch length of the branch pipe is longer than the lower branch length, the lower branch pipe side of the branch pipe 2 is shorter, the stay time of the material therein is shorter, the upper branch pipe side is longer, and the stay time of the material therein is longer.

In the case where the concentration of the material deviates from a predetermined value due to the unstable pumping, if the branch pipe 2 is not provided, the concentration deviation is always kept in the axial direction in the reaction tube 3, and in the case where the branch pipe 2 is provided, the flow path is different in different branch pipes after the material of the concentration deviation is branched into the branch pipe 2, and the residence time is different, so that the concentration deviation is reduced.

The pipe diameter of the branch pipe 2 may be the same as or different from the reaction pipe 3.

The reaction tube 3 may be a continuous structure as shown in fig. 1, or may be a segmented structure as shown in fig. 2 and 3. When the structure is of a continuous structure, the structure is a front section close to the feed inlet, a rear section close to the discharge outlet and a middle section in the middle.

In general, in the initial reaction stage where the concentration of the reaction raw materials is high, the reaction speed is high, and the subsequent reaction is gradually slowed down, so that the residence of the reactants in the tube and the reaction time are required to be delayed. Thus, in some embodiments, the reaction tube 3 has a small tube diameter in the front section, a small tube volume, a fast flow rate of the material in this section, and a short residence time, but the middle and rear sections have a larger volume than the front section, thereby increasing the residence time of the material in the sections of tubes. The volume of the middle and rear stages of the reaction tube 3 can be increased by increasing the tube diameter and/or the length of the tube.

For the segmented structure, taking FIG. 2 as an example, it is preferable that the volume of the first-stage reaction tube 3-1 > the volume of the second-stage reaction tube 3-2 > the volume of the third-stage reaction tube 3-3. Gtoreq.the volume of the fourth-stage reaction tube 3-4.

In some embodiments, where reactor tube 3 comprises a 2-stage reactor tube, first-stage reactor tube 3-1: the volume ratio of the second stage reaction tube 3-2 may be about 1 (5-15); when the reactor comprises 3 sections of reaction tubes, the first section of reaction tube 3-1: second stage reaction tube 3-2: the volume ratio of the third stage reaction tube 3-3 may be about 1: (5-15): (20-40); when the reactor comprises 4 sections of reaction tubes, the first section of reaction tube 3-1: second stage reaction tube 3-2: third stage reaction tube 3-2: the volume ratio of the fourth stage reaction tubes 3-4 may be about 1: (5-15): (20-40): (20-40).

The specific size of the pipe diameter of the reaction pipe 3 is reasonably determined according to factors such as productivity on the premise of ensuring that the materials can reach the required flow rate in the pipe so as to realize full mixing. Tube diameters of, for example, about 2-10mm may be used in small scale production and tube diameters of, for example, about 15-40mm may be used in large scale production.

In large-scale production, the tube diameter of the reaction tube 3 is increased, and in order to improve the mixing efficiency of the materials therein, it is preferable to provide a static mixer in the reaction tube 3. The static mixture is prepared by adopting known products, and no special requirement exists. The amount is also reasonably determined according to the desired mixing effect, equipment size, and other factors.

The improved tubular reactor 1 of the present utility model can be used in any application where conventional tubular reactors can be used.

In the present inventors produced sulfonyl compounds by oxidizing sulfur-based compounds with hydrogen peroxide as a catalyst through the above-mentioned modified tubular reactor 1, it was found that the modified tubular reactor 1 could solve the problem of thermal runaway of the reaction and promote the progress of the reaction to some extent, but could not proceed sufficiently, and that more than 30% of the sulfinyl intermediate could not continue to react in the tubular reactor 1.

The production plant according to the utility model is mainly characterized in that the improved tubular reactor 1 described above is used in series with a tank reactor 7.

Such a serial structure can solve the problem of thermal runaway of the reaction by the tubular reactor 1, while allowing the reaction to proceed sufficiently by the tank reactor 7.

The tank reactor 7 may be any known one, and is not particularly limited. Preferably, the tank reactor 7 is provided with stirring or external circulation means.

In order to achieve continuous production, 2 or more tank reactors 7 may be provided in series as shown in fig. 5, or 2 or more tank reactors 7 may be provided in parallel as shown in fig. 6.

The tank reactor 7 may be withdrawn in a continuous, semi-continuous or batch mode.

In some embodiments, the ratio of the total volume of the reaction tubes 3 of the tubular reactor 7 to the volume of the tank reactor 7 is about 1 (5-1000).

Other necessary components may be further included in the production apparatus of the present application as needed.

In some specific embodiments, a solution obtained by dissolving 4-methylthio-2, 3-dimethylbromobenzene in a solvent such as acetic acid, etc., an aqueous sodium tungstate solution as a catalyst, and hydrogen peroxide as an oxidant are respectively injected into a feed pipe as three feeds, and then are converged and enter the tubular reactor 1.

In the front stage of the reaction tube 3 near the feed port, for example, the first stage reaction tube 3-1 in fig. 2,3 and 6, the reaction rate is very fast and the heat release amount is large, and therefore, it is preferable to design the stage reaction tube to be smaller in tube diameter and smaller in volume than the subsequent reaction tube in order to increase the specific surface area of flow rate and heat release and shorten the residence and reaction time of the reactants in the stage reaction tube.

In the middle section of the reaction tube 3, for example, the second-stage reaction tube 3-2 in fig. 2,3 and 6, the reaction speed of the material is somewhat slowed down, and therefore, the volume of the middle section of the reaction tube 3 is appropriately increased compared to the front section of the reaction tube 3 to increase the residence and reaction time of the material in the section of the tube.

In the rear section of the reaction tube 3, for example, the third-stage reaction tube 3-3 and the fourth-stage reaction tube 3-4 in fig. 2,3 and 6, the material concentration and the reaction speed are further reduced, and therefore, the volume of the rear section of the reaction tube 3 can be further appropriately increased as compared with the middle section of the reaction tube 3 to increase the residence and reaction time of the material in the section of the tube.

The volume expansion of the middle and rear pipes of the reaction pipe 3 can be achieved by increasing the pipe diameter and/or extending the pipe length, the pipe diameter is related to the flow velocity and mixing effect of the materials in the pipe, the pipe length is related to the pressure drop and the whole scale of the equipment, and the person skilled in the art can reasonably determine the factors.

In some embodiments, the total residence time of the material in the tubular reactor 1 is about 2 to 10 minutes, preferably 3 to 5 minutes.

The tubular reactor 1 and the tank reactor 7 are each independently and optionally placed in a jacket, and medium is introduced into the jacket to control the temperature to a desired range.

By the tandem structure of the present utility model, most of the reaction is completed in the tubular reactor 1, the hydrogen peroxide concentration with high risk coefficient is reduced to a low level, and then the material is introduced into the tank reactor 7, and the sulfinyl intermediate which cannot continue to react in the tubular reactor 1 is finally fully reacted by stirring and/or external circulation, thereby achieving both safety and efficiency of the reaction.

Example 1

The production equipment shown in FIG. 6 is adopted in the embodiment, wherein the tubular reactor 1 is a tetrafluoro tubular reactor, the first section of reaction tube 3-1 has an inner diameter of 2mm and a length of 2m, the second section of reaction tube 3-2 has an inner diameter of 3mm and a length of 10m, the third section of reaction tube 3-3 has an inner diameter of 3mm and a length of 20m, and the fourth section of reaction tube 3-4 has an inner diameter of 3mm and a length of 20m. The kettle reactor 7 is a conventional reaction kettle with stirring.

Dissolving 4-methylthio-2, 3-dimethyl bromobenzene in acetic acid at room temperature, and stirring thoroughly until the solid is completely dissolved (raw material solution A); 25-30% hydrogen peroxide water solution is used as a raw material solution B; sodium tungstate dihydrate was added to deionized water and stirred well until the solid was completely dissolved (stock solution C). Heating the raw material solution A to 60 ℃; the raw material solution A, the raw material solution B and the raw material solution C are simultaneously conveyed into the tubular reactor 1 by three plunger pumps according to the feeding speeds of 44g/min, 37.57g/min and 8.68g/min, the jacket outside the tubular reactor 1 is heated and kept at 85-90 ℃ by introducing hot water, and the materials coming out from the fourth-stage reaction tube 3-4 are introduced into the kettle reactor 7 and fully stirred for about 30min. HPLC monitors the material coming out of the fourth stage reaction tube 3-4 and 30min after introduction into the tank reactor 7. Slowly cooling and crystallizing after the reaction is completed, adding sodium bisulphite to quench system peroxide after the temperature of the solution is reduced to 0-10 ℃, and stirring and crystallizing for 1h; the system was filtered under reduced pressure, the filter cake was washed once with ice water, filtered and dried to finally obtain 4-methanesulfonyl-2, 3-dimethylbromobenzene, the content and yield of which are shown in the following table.

HPLC conditions:

the monitoring method comprises the following steps:

the appropriate amount of reaction solution was sucked up by capillary tubes and the centrifuge tubes were topped up with pure acetonitrile. 60 mu L of the mixture was injected into a liquid chromatograph by a flat head microsyringe, and 4-methylsulfanyl-2, 3-dimethylbromobenzene (raw material), 4-methylsulfonyl-2, 3-dimethylbromobenzene (product) and 4-methylsulfinyl-2, 3-dimethylbromobenzene (intermediate) were integrated, and the results were expressed by an area normalization method. 4-methylsulfonyl-2, 3-dimethylbromobenzene has a retention time of about 4.0min, 4-methylsulfanyl-2, 3-dimethylbromobenzene has a retention time of about 11.5min, 4-methylsulfinyl-2, 3-dimethylbromobenzene has a retention time of about 3.5min, and the remaining amount of 4-methylsulfanyl-2, 3-dimethylbromobenzene is not more than 1% and 4-methylsulfinyl-2, 3-dimethylbromobenzene is not more than 1%.

TABLE 1 discharge tracking data for tubular reactors

	1	2	3	4	5
						Raw materials	---	---	---	---	---
Intermediate products	41.49％	47.78％	41.72％	39.18％	42.64％
						Product(s)	58.51％	52.22％	58.28％	60.82％	57.36％

Note that: the reaction was completed, and the trace detection showed no substance, as follows.

Table 2 tank reactor material tracking data

	1	2
			Raw materials	---	---
Intermediate products	0.13％	0.31％
			Product(s)	99.87％	99.69％

Example 2

The same as in example 1 was conducted except that the branch pipe 2 was not provided in the tubular reactor 1.

The discharge of the tubular reactor 1 and the material tracking data of the tank reactor 7 of this example are shown in tables 3 and 4, respectively.

TABLE 3 discharge tracking data for tubular reactors

	1	2	3
				Raw materials	---	---	---
Intermediate products	63.32％	58.80％	63.09％
				Product(s)	36.68％	41.20％	36.91％

Table 4 tank reactor material tracking data

	1	2
			Raw materials	---	---
Intermediate products	0.17％	0.20％
			Product(s)	99.83％	99.80％

As is evident from the results of examples 1 and 2, the reaction of the material exiting the tubular reactor 1 was insufficient, more than 30% of the sulfinyl intermediate was unreacted, and the reaction was carried out in the tank reactor 7 until the residual amount of intermediate was < 1%. In addition, the tubular reactor 1 of example 1 allows more sulfinyl intermediate to react therein, which is advantageous in reducing the hydrogen peroxide concentration entering the tank reactor 7 and better controlling the risk of thermal runaway of the reaction.

Claims

1. The tubular reactor is characterized by comprising a reaction tube and branch tubes, wherein the reaction tube is a continuous tube or is divided into more than two sections, and the branch tubes are directly arranged on the reaction tube and/or between the reaction tubes.

2. The tubular reactor of claim 1, wherein the reaction tube is divided into two sections, the first section of reaction tube: the volume ratio of the second stage reaction tube is 1 (5-15).

3. The tubular reactor of claim 2, wherein the reaction tube is divided into three sections, the first section reaction tube: second stage reaction tube: the volume ratio of the third section reaction tube is 1: (5-15): (20-40).

4. The tubular reactor of claim 2, wherein the reaction tube is divided into four sections, the first section reaction tube: second stage reaction tube: third stage reaction tube: the volume ratio of the fourth section reaction tube is 1: (5-15): (20-40): (20-40).

5. A tubular reactor according to any one of claims 1 to 4, wherein a static mixer is provided in the reaction tube.

6. The tubular reactor according to any one of claims 1 to 4, wherein the tubular reactor is placed in a jacket.

7. A production facility comprising a tubular reactor and a tank reactor in series, the tubular reactor being as claimed in any one of claims 1 to 6.

8. The production facility of claim 7 wherein the tank reactors are more than 2 tank reactors in series or parallel.

9. The production plant according to claim 7 or 8, characterized in that the tank reactor is provided with stirring and/or external circulation means.

10. The production facility as claimed in claim 7, wherein the ratio of the total volume of the reaction tubes of the tubular reactor to the volume of the tank reactor is 1 (5-1000).