阅读说明：本技术 一种连续制备间二氯苯的方法及其装置 (Method and device for continuously preparing m-dichlorobenzene ) 是由 王进 廖道华 郑金豪 谌斌斌 綦菲 潘光飞 曾挺 于 2021-08-12 设计创作，主要内容包括：本发明公开了一种连续制备间二氯苯的方法及其装置,包括以下步骤：将邻二氯苯连续进入搅拌反应器,在氯化铝和辅助催化剂的催化作用下异构化为间二氯苯；在反应温度下合成产物被汽化,得到汽体混合物；汽体混合物连续依次进入盐塔、高效精馏塔,间二氯苯连续从高效精馏塔塔顶采出,回流液体从高效精馏塔塔底返回搅拌反应釜。本发明连续制备间二氯苯的方法及其装置可以有效避免氯化铝升华而堵塞管道和精馏塔填料的问题,并且可连续操作,实现工业化生产,经济效益高,适合大规模推广。(The invention discloses a method and a device for continuously preparing m-dichlorobenzene, comprising the following steps: continuously feeding o-dichlorobenzene into a stirring reactor, and isomerizing the o-dichlorobenzene into m-dichlorobenzene under the catalytic action of aluminum chloride and an auxiliary catalyst; the synthesis product is vaporized at the reaction temperature to obtain a vapor mixture; the gas mixture continuously and sequentially enters a salt tower and a high-efficiency rectifying tower, m-dichlorobenzene is continuously extracted from the top of the high-efficiency rectifying tower, and the reflux liquid returns to the stirring reaction kettle from the bottom of the high-efficiency rectifying tower. The method and the device for continuously preparing m-dichlorobenzene can effectively avoid the problem that aluminum chloride is sublimated to block pipelines and rectifying tower fillers, can be continuously operated, realize industrial production, have high economic benefit and are suitable for large-scale popularization.)

1. An apparatus for continuously producing m-dichlorobenzene, comprising: the device comprises a stirring reactor (1), wherein a feeding hole and a discharging hole are formed in the upper part of the stirring reactor (1); the salt tower (2), the salt tower (2) is filled with solid sodium chloride, and the salt tower (2) is provided with a heating and heat-preserving device; the high-efficiency rectifying tower (3), wherein the high-efficiency rectifying tower (3) is selected from any one of a plate tower and a packed tower; a tower top condenser (4).

2. A method for continuously preparing m-dichlorobenzene by using the device of claim 1, which comprises the following steps: continuously feeding reaction raw materials into a stirring reactor (1), and isomerizing the reaction raw materials into m-dichlorobenzene under the catalytic action of aluminum chloride and an auxiliary catalyst; the synthesis product is vaporized at the reaction temperature to obtain a vapor mixture; the gas mixture continuously and sequentially enters the salt tower (2) and the high-efficiency rectifying tower (3), m-dichlorobenzene is continuously extracted from the top of the high-efficiency rectifying tower (3), and reflux liquid returns to the stirring reaction kettle from the bottom of the high-efficiency rectifying tower (3); the reaction raw material is one or two of o-dichlorobenzene and p-dichlorobenzene.

3. The method for continuously preparing m-dichlorobenzene according to claim 2, wherein the auxiliary catalyst is selected from one of magnesium chloride/hydrogen chloride and lithium chloride/hydrogen chloride.

4. The method for continuously producing m-dichlorobenzene according to claim 2, wherein the reaction temperature of said stirring reactor (1) is 180-200 ℃.

5. The method for the continuous production of m-dichlorobenzene according to claim 2, wherein said salt tower (2) is operated at a temperature of 180-200 ℃.

The process for the continuous preparation of m-dichlorobenzene according to claim 2, wherein the residence time of said vapor mixture in salt tower (2) is between 5 seconds and 100 seconds.

6. The method for continuously producing m-dichlorobenzene according to claim 2, wherein theoretical plate number of said high-efficiency rectifying tower (3) is 70-90, and operation reflux ratio is 15-20.

7. The process for the continuous preparation of m-dichlorobenzene according to claim 2, wherein said stirred reactor (1) is charged with mixed dichlorobenzene before feeding.

8. The method for continuously preparing m-dichlorobenzene according to claims 2-7, comprising the following steps: 250 parts of mixed dichlorobenzene, 60 parts of aluminum chloride and 30 parts of magnesium chloride are filled into a stirring reactor (1), the continuous feeding flow is 30g/h of o-dichlorobenzene, hydrogen chloride gas is continuously introduced, and the reaction temperature is 180-200 ℃; the vapor mixture vaporized from the stirring reactor (1) enters a salt tower (2), the operating temperature of the salt tower (2) is 180-200 ℃, and the complex NaAlCl formed is₄The molten salt is discharged from the bottom of the salt tower (2), and the vapor mixture without aluminum chloride enters the high-efficiency rectifying tower (3) from the top of the salt tower (2); the m-dichlorobenzene is continuously extracted from the top of the high-efficiency rectifying tower (3).

9. The method for continuously preparing m-dichlorobenzene according to claims 2-7, comprising the following steps: 250 parts of mixed dichlorobenzene, 60 parts of aluminum chloride and 30 parts of magnesium chloride are filled into a stirring reactor (1), the continuous feeding flow rate of the mixed dichlorobenzene is 30g/h, hydrogen chloride gas is continuously introduced, and the reaction temperature is 180-200 ℃; the vapor mixture vaporized from the stirring reactor (1) enters a salt tower (2), the operating temperature of the salt tower (2) is 180-200 ℃, and the complex NaAlCl formed is₄The molten salt is discharged from the bottom of the salt tower (2), and the vapor mixture without aluminum chloride enters the high-efficiency rectifying tower (3) from the top of the salt tower (2); m-dichlorobenzene is continuously extracted from the top of the high-efficiency rectifying tower (3); the weight ratio of o-dichlorobenzene to p-dichlorobenzene in the mixed dichlorobenzene is 1: 1.

Technical Field

The invention relates to the technical field of chemical industry, in particular to a method and a device for continuously preparing m-dichlorobenzene.

Background

M-dichlorobenzene is an important organic chemical intermediate and can be used for synthesizing bactericides such as propiconazole and difenoconazole. The isomerization of o-dichlorobenzene and p-dichlorobenzene into m-dichlorobenzene has two main types of catalysts: one is a zeolite catalyst such as ZSM-5; second is aluminum chloride. The use of zeolites as catalysts often requires high temperatures of 311 ℃ to 411 ℃ and pressures of 3MPa to 4MPa, fixed-bed reactors being used (DE3334673, US4962245, US 5466111). The use of aluminium chloride as catalyst is generally carried out batchwise at a reaction temperature of 151 ℃ to 111 ℃ and with a product composition of from 31% to 51% of m-dichlorobenzene, from 31% to 51% of o-dichlorobenzene and from 11% to 21% of p-dichlorobenzene (U.S. Pat. No. 3,2666115, U.S. Pat. No. 3,2727175, U.S. Pat. No. 3,9321). The above reaction gives mixed dichlorobenzene which usually requires separation by crystallization + rectification due to the small difference in boiling points of the three isomers.

The document (DE 1121323) reports a continuous reactive rectification process in which the starting material o-dichlorobenzene is continuously fed into a stirred reactor and isomerized into m-dichlorobenzene by the catalytic action of aluminum chloride and magnesium chloride; the reaction product is vaporized at the temperature of 111 ℃ and 115 ℃, the vapor mixture enters a high-efficiency rectifying tower, and 91 percent of m-dichlorobenzene (containing 11 percent of p-dichlorobenzene) is obtained from the top of the high-efficiency rectifying tower. However, in the experiment of the method, aluminum chloride has sublimation phenomenon, so that pipelines and rectifying tower fillers are blocked, and industrialization is difficult to realize.

Disclosure of Invention

In order to solve the defects of the prior art, the invention provides a method and a device for continuously preparing m-dichlorobenzene, which mainly solve the technical difficulty that aluminum chloride is sublimated to block pipelines and fillers in a continuous reaction rectification method.

The technical scheme adopted by the invention for solving the problems is as follows: an apparatus for continuously producing m-dichlorobenzene, comprising: the upper part of the stirring reactor is provided with a feeding hole and a discharging hole; the salt tower is filled with solid sodium chloride and is provided with a heating and heat-preserving device; the high-efficiency rectifying tower is selected from any one of a plate tower and a packed tower; a tower top condenser.

Another object of the present invention is to provide a method for continuously preparing m-dichlorobenzene using said apparatus, comprising the steps of: continuously feeding reaction raw materials into a stirring reactor, and isomerizing the reaction raw materials into m-dichlorobenzene under the catalytic action of aluminum chloride and an auxiliary catalyst; the synthesis product is vaporized at the reaction temperature to obtain a vapor mixture; the gas mixture continuously and sequentially enters a salt tower and a high-efficiency rectifying tower, m-dichlorobenzene is continuously extracted from the top of the high-efficiency rectifying tower, and reflux liquid returns to the stirring reaction kettle from the bottom of the high-efficiency rectifying tower; the reaction raw material is one or two of o-dichlorobenzene and p-dichlorobenzene.

Wherein a small amount of aluminum chloride dimer sublimate in the vapor mixture entering the salt tower forms a complex (NaAlCl) with sodium chloride₄) And is trapped.

Further, the auxiliary catalyst is selected from one of magnesium chloride/hydrogen chloride and lithium chloride/hydrogen chloride, wherein the magnesium chloride and the lithium chloride can respectively form a complex or a molten salt with aluminum chloride under reaction conditions so as to reduce or avoid sublimation of the aluminum chloride, and the hydrogen chloride provides protons required for intramolecular transfer (isomerization) of chlorine radicals.

Further, the reaction temperature of the stirred reactor was 111 ℃ 1211 ℃, which is just slightly above the boiling temperature of dichlorobenzene (due to the resistance of the rectification column) under atmospheric pressure.

Further, the operating temperature of the salt column was 1211 ℃ at 111 ℃.

Wherein, in order to make aluminum chloride sublimate fully react with sodium chloride solid, the vaporThe residence time of the mixture flowing through the salt tower is more than 5 seconds, the operating temperature of the salt tower is more than 111 ℃, and the complex (NaAlCl)₄) The melting point is 145-151 ℃ and the operating temperature of the salt column is preferably 111-211 ℃ so that the complex (NaAlCl) formed₄) The salt tower is discharged as molten salt from the bottom of the salt tower. And the vapor mixture without aluminum chloride enters the high-efficiency rectifying tower from the top of the salt tower.

Further, the residence time of the vapor mixture in the salt tower is between 5 seconds 1111 seconds.

Furthermore, the theoretical plate number of the high-efficiency rectifying tower is 71-91, and the operation reflux ratio is 15-21. Due to the corrosiveness of the hydrogen chloride, an anticorrosive material such as a ceramic filler is selected, the boiling point difference between o-dichlorobenzene and m-dichlorobenzene is small, namely 5-7 ℃, so that the theoretical plate number of the high-efficiency rectifying tower is 71-91, and the operation reflux ratio is 15-21.

Further, the stirred reactor was charged with mixed dichlorobenzene just prior to feeding.

Further, a method for continuously preparing m-dichlorobenzene, comprising the following steps: 251 parts of mixed dichlorobenzene, 61 parts of aluminum chloride and 31 parts of magnesium chloride are filled into a stirring reactor, the continuous feeding flow is 31g/h of o-dichlorobenzene, hydrogen chloride gas is continuously fed in, and the reaction temperature is 1211 ℃ at 111 ℃; the vapor mixture vaporized from the stirring reactor enters a salt tower, the operating temperature of the salt tower is 1211 ℃ at 111 ℃, and the complex NaAlCl is formed₄Discharging the molten salt from the bottom of the salt tower, and allowing the vapor mixture without aluminum chloride to enter a high-efficiency rectifying tower from the top of the salt tower; m-dichlorobenzene is continuously extracted from the top of the high-efficiency rectifying tower.

Further, a method for continuously preparing m-dichlorobenzene, comprising the following steps: 251 parts of mixed dichlorobenzene, 61 parts of aluminum chloride and 31 parts of magnesium chloride are filled into a stirring reactor, the continuous feeding flow rate of the mixed dichlorobenzene is 31g/h, hydrogen chloride gas is continuously fed in, and the reaction temperature is 1211 ℃ at 111 ℃; the vapor mixture vaporized from the stirring reactor enters a salt tower, the operating temperature of the salt tower is 1211 ℃ at 111 ℃, and the complex NaAlCl is formed₄Discharging as molten salt from the bottom of the salt tower, and removing aluminum chloride from the vapor mixture at the top of the salt towerPart of the wastewater enters a high-efficiency rectifying tower; m-dichlorobenzene is continuously extracted from the top of the high-efficiency rectifying tower; the weight ratio of o-dichlorobenzene to p-dichlorobenzene in the mixed dichlorobenzene is 1: 1.

The invention has the advantages that:

(1) the device for continuously preparing m-dichlorobenzene comprises three parts of a stirring reactor, a salt tower, a high-efficiency rectifying tower and a tower top condenser, wherein the salt tower is provided with a salt tower device, solid sodium chloride is filled in the salt tower, and a small amount of aluminum chloride dimer sublimate in a vapor mixture entering the salt tower forms a complex (NaAlCl) with sodium chloride₄) The gas mixture without aluminum chloride enters the efficient rectifying tower from the top of the salt tower after being intercepted, so that the problem that the aluminum chloride is sublimated to block pipelines and fillers of the rectifying tower can be effectively avoided;

(2) auxiliary agents of magnesium chloride/hydrogen chloride and lithium chloride/hydrogen chloride are added into a stirring reactor, the magnesium chloride and the lithium chloride can respectively form a complex or molten salt with aluminum chloride under the reaction condition so as to reduce or avoid the sublimation of the aluminum chloride, and the hydrogen chloride provides protons required by the intramolecular transfer (isomerization) of chlorine radicals;

(3) the method and the device for continuously preparing m-dichlorobenzene can effectively avoid the problem that aluminum chloride is sublimated to block pipelines and rectifying tower fillers, the content of the obtained product, namely m-dichlorobenzene, is high and is 11191 percent, few byproducts are generated, the method and the device can be continuously operated, the industrial production is realized, the economic benefit is high, and the method and the device are suitable for large-scale popularization.

In addition to the objects, features and advantages described above, other objects, features and advantages of the present invention are also provided. The present invention will be described in further detail below.

Drawings

FIG. 1 is an apparatus for continuously preparing m-dichlorobenzene according to the present invention.

Description of reference numerals: 1-stirring reactor, 2-salt tower, 3-high-efficiency rectifying tower, 4-tower top condenser, D-tower top collecting material (m-dichlorobenzene), E-NaCl, F-feeding material (o-dichlorobenzene or mixture of o-dichlorobenzene and p-dichlorobenzene), and G-NaAlCl₄。

Detailed Description

The following detailed description of embodiments of the invention, but the invention can be practiced in many different ways, as defined and covered by the claims.

Example 1

Method and device for continuously preparing m-dichlorobenzene

251g of mixed dichlorobenzene, 61g of aluminum chloride and 31g of magnesium chloride are filled into the stirring reactor 1, the continuous feeding flow F is 31g/h of o-dichlorobenzene, hydrogen chloride gas is continuously introduced, and the reaction temperature (boiling point temperature) is 115 ℃; the vapor mixture vaporized from the stirring reactor 1 enters a salt tower 2, the operating temperature of the salt tower 2 is 115 ℃, and the complex NaAlCl formed is₄And discharging the molten salt from the bottom of the salt tower 2, introducing the vapor mixture without aluminum chloride into the high-efficiency rectifying tower 3 from the top of the salt tower 2, and continuously extracting m-dichlorobenzene from the top of the high-efficiency rectifying tower 3 at an extraction flow D of 31g/h, wherein the contents of the m-dichlorobenzene, the p-dichlorobenzene and the o-dichlorobenzene are 91%, 9.5% and 1.5%.

Wherein the operation reflux ratio of the high-efficiency rectifying tower 3 is 17, and reflux liquid returns to the stirring reactor 1 from the bottom of the high-efficiency rectifying tower 3; the salt tower 2 is provided with a heating and heat-preserving device such as a jacket and the like, and the theoretical plate number of the high-efficiency rectifying tower 3 is 11; the residence time of the vapor mixture in the salt tower was 11 seconds.

1611g of m-dichlorobenzene is cumulatively extracted from the top of the high-efficiency rectifying tower 3, the catalyst in the stirring reactor 1 needs to be replaced, and the solid sodium chloride in the salt tower 2 needs to be supplemented.

Example 2

Method and device for continuously preparing m-dichlorobenzene

251g of mixed dichlorobenzene, 61g of aluminum chloride and 31g of magnesium chloride are filled into the stirring reactor 1, the continuous feeding flow F is 31g/h of o-dichlorobenzene, hydrogen chloride gas is continuously introduced, and the reaction temperature (boiling point temperature) is 111 ℃; the vapor mixture vaporized from the stirring reactor 1 enters a salt tower 2, the operating temperature of the salt tower 2 is 111 ℃, and the complex NaAlCl is formed₄The molten salt is discharged from the bottom of the salt tower 2, and the vapor mixture without aluminum chloride enters the high-efficiency rectifying tower 3 from the top of the salt tower 2; m-dichlorobenzene is continuously extracted from the top of the high-efficiency rectifying tower 3 to obtain an extracted flowThe amount D is 31g/h, and the contents are 15% of m-dichlorobenzene, 14% of p-dichlorobenzene and 1% of o-dichlorobenzene.

Wherein the operation reflux ratio of the high-efficiency rectifying tower 3 is 15, and reflux liquid returns to the stirring reactor 1 from the bottom of the high-efficiency rectifying tower 3; the salt tower 2 is provided with a heating and heat-preserving device, and the theoretical plate number of the high-efficiency rectifying tower 3 is 71; the residence time of the vapor mixture in the salt tower was 5 seconds.

1211g of m-dichlorobenzene is cumulatively extracted from the top of the high-efficiency rectifying tower 3, the catalyst in the stirring reactor 1 needs to be replaced, and the solid sodium chloride in the salt tower 2 needs to be supplemented appropriately.

Example 3

Method and device for continuously preparing m-dichlorobenzene

251g of mixed dichlorobenzene, 61g of aluminum chloride and 31g of magnesium chloride are filled into the stirring reactor 1, the continuous feeding flow F is 31g/h of o-dichlorobenzene, hydrogen chloride gas is continuously introduced, and the reaction temperature (boiling point temperature) is 191 ℃; the vapor mixture vaporized from the stirring reactor 1 enters a salt tower 2, the operating temperature of the salt tower 2 is 191 ℃, and the complex NaAlCl formed is₄The molten salt is discharged from the bottom of the salt tower 2, and the vapor mixture without aluminum chloride enters the high-efficiency rectifying tower 3 from the top of the salt tower 2; m-dichlorobenzene is continuously extracted from the top of the high-efficiency rectifying tower 3, the extraction flow D is 31g/h, and the contents of the m-dichlorobenzene, the p-dichlorobenzene and the o-dichlorobenzene are 17.5%, 11.9% and 1.6%.

Wherein the operation reflux ratio of the high-efficiency rectifying tower 3 is 21, and reflux liquid returns to the stirring reactor 1 from the bottom of the high-efficiency rectifying tower 3; the salt tower 2 is provided with a heating and heat-preserving device; the theoretical plate number of the high-efficiency rectifying tower 3 is 91; the residence time of the vapor mixture in the salt tower was 111 seconds.

1111g m-dichlorobenzene is cumulatively extracted from the top of the high-efficiency rectifying tower 3, the catalyst in the stirring reactor 1 needs to be replaced, and the solid sodium chloride in the salt tower 2 needs to be supplemented properly.

Example 4

Method and device for continuously preparing m-dichlorobenzene

251g of mixed dichlorobenzene, 61g of aluminum chloride and 31g of magnesium chloride are charged into the stirred reactor 1, and the mixture is continuously fed at a flow rate F of 31g/hDichlorobenzene is mixed, wherein the weight ratio of o-dichlorobenzene to p-dichlorobenzene in the mixed dichlorobenzene is 1:1, hydrogen chloride gas is continuously introduced, and the reaction temperature (boiling point temperature) is 115 ℃; the vapor mixture vaporized from the stirring reactor 1 enters a salt tower 2, the operating temperature of the salt tower 2 is 115 ℃, and the complex NaAlCl formed is₄The molten salt is discharged from the bottom of the salt tower 2, the vapor mixture without aluminum chloride enters the high-efficiency rectifying tower 3 from the top of the salt tower 2, m-dichlorobenzene is continuously extracted from the top of the high-efficiency rectifying tower 3, the extraction flow is 31g/h, and the contents of m-dichlorobenzene, p-dichlorobenzene and o-dichlorobenzene are 15.2%, 14.3% and 1.5%.

Wherein the operation reflux ratio of the high-efficiency rectifying tower 3 is 17, and reflux liquid returns to the stirring reactor 1 from the bottom of the high-efficiency rectifying tower 3; the salt tower 2 is provided with a heating and heat-preserving device such as a jacket and the like, and the theoretical plate number of the high-efficiency rectifying tower 3 is 11; the residence time of the vapor mixture in the salt tower was 51 seconds.

1611g of m-dichlorobenzene is cumulatively extracted from the top of the high-efficiency rectifying tower 3, the catalyst in the stirring reactor 1 needs to be replaced, and the solid sodium chloride in the salt tower 2 needs to be supplemented.

Example 5

Method and device for continuously preparing m-dichlorobenzene

251g of mixed dichlorobenzene, 61g of aluminum chloride and 31g of magnesium chloride are filled into a stirring reactor 1, the continuous feeding flow F is 31g/h of mixed dichlorobenzene, the weight ratio of o-dichlorobenzene to p-dichlorobenzene in the mixed dichlorobenzene is 1:1, hydrogen chloride gas is continuously fed in, and the reaction temperature (boiling point temperature) is 211 ℃; the vapor mixture vaporized from the stirring reactor 1 enters a salt tower 2, the operating temperature of the salt tower 2 is 211 ℃, and the complex NaAlCl formed is₄The molten salt is discharged from the bottom of the salt tower 2, and the vapor mixture without aluminum chloride enters the high-efficiency rectifying tower 3 from the top of the salt tower 2; m-dichlorobenzene is continuously extracted from the top of the high-efficiency rectifying tower 3, the extraction flow D is 31g/h, and the contents of the m-dichlorobenzene, the p-dichlorobenzene and the o-dichlorobenzene are 11%, 19.2% and 1.1%.

Wherein the operation reflux ratio of the high-efficiency rectifying tower 3 is 15, and reflux liquid returns to the stirring reactor 1 from the bottom of the high-efficiency rectifying tower 3; the salt tower 2 is provided with a heating and heat-preserving device, and the theoretical plate number of the high-efficiency rectifying tower 3 is 71; the residence time of the vapor mixture in the salt tower was 15 seconds.

1211g of m-dichlorobenzene is cumulatively extracted from the top of the high-efficiency rectifying tower 3, the catalyst in the stirring reactor 1 needs to be replaced, and the solid sodium chloride in the salt tower 2 needs to be supplemented appropriately.

Example 6

Method and device for continuously preparing m-dichlorobenzene

251g of mixed dichlorobenzene, 61g of aluminum chloride and 31g of lithium chloride are filled into the stirring reactor 1, the continuous feeding flow F is 31g/h of o-dichlorobenzene, hydrogen chloride gas is continuously introduced, and the reaction temperature (boiling point temperature) is 115 ℃; the vapor mixture vaporized from the stirring reactor 1 enters a salt tower 2, the operating temperature of the salt tower 2 is 115 ℃, and the complex NaAlCl formed is₄And discharging the molten salt from the bottom of the salt tower 2, feeding the vapor mixture without aluminum chloride into the high-efficiency rectifying tower 3 from the top of the salt tower 2, continuously extracting m-dichlorobenzene from the top of the high-efficiency rectifying tower 3, wherein the flow rate of the extracted material is 31g/h, and the contents of the extracted material are 16.2% of m-dichlorobenzene, 13% of p-dichlorobenzene and 1.1% of o-dichlorobenzene.

Wherein the operation reflux ratio of the high-efficiency rectifying tower 3 is 17, and reflux liquid returns to the stirring reactor 1 from the bottom of the high-efficiency rectifying tower 3; the salt tower 2 is provided with a heating and heat-preserving device such as a jacket and the like, and the theoretical plate number of the high-efficiency rectifying tower 3 is 11; the residence time of the vapor mixture in the salt tower was 21 seconds.

1611g of m-dichlorobenzene is cumulatively extracted from the top of the high-efficiency rectifying tower 3, the catalyst in the stirring reactor 1 needs to be replaced, and the solid sodium chloride in the salt tower 2 needs to be supplemented.

Example 7

Method and device for continuously preparing m-dichlorobenzene

251g of mixed dichlorobenzene, 61g of aluminum chloride and 31g of lithium chloride are filled into the stirring reactor 1, the continuous feeding flow F is 31g/h of o-dichlorobenzene, hydrogen chloride gas is continuously introduced, and the reaction temperature (boiling point temperature) is 111 ℃; the vapor mixture vaporized from the stirring reactor 1 enters a salt tower 2, the operating temperature of the salt tower 2 is 111 ℃, and the complex NaAlCl is formed₄Discharged as molten salt from the bottom of the salt tower 2, and vapor with aluminum chloride removedThe mixture enters the high-efficiency rectifying tower 3 from the top of the salt tower 2, m-dichlorobenzene is continuously extracted from the top of the high-efficiency rectifying tower 3, the flow rate of the extracted material is 31g/h, and the contents of m-dichlorobenzene, p-dichlorobenzene and o-dichlorobenzene are 11.4%, 11.2% and 1.4%.

Wherein the operation reflux ratio of the high-efficiency rectifying tower 3 is 21, and reflux liquid returns to the stirring reactor 1 from the bottom of the high-efficiency rectifying tower 3; the salt tower 2 is provided with a heating and heat-preserving device such as a jacket and the like, and the theoretical plate number of the high-efficiency rectifying tower 3 is 91; the residence time of the vapor mixture in the salt tower was 5 seconds.

1611g of m-dichlorobenzene is cumulatively extracted from the top of the high-efficiency rectifying tower 3, the catalyst in the stirring reactor 1 needs to be replaced, and the solid sodium chloride in the salt tower 2 needs to be supplemented.

Example 8

Method and device for continuously preparing m-dichlorobenzene

251g of mixed dichlorobenzene, 61g of aluminum chloride and 31g of lithium chloride are filled into a stirring reactor 1, the continuous feeding flow F is 31g/h of mixed dichlorobenzene, the weight ratio of o-dichlorobenzene to p-dichlorobenzene in the mixed dichlorobenzene is 1:1, hydrogen chloride gas is continuously fed in, and the reaction temperature (boiling point temperature) is 191 ℃; the vapor mixture vaporized from the stirring reactor 1 enters a salt tower 2, the operating temperature of the salt tower 2 is 191 ℃, and the complex NaAlCl formed is₄The molten salt is discharged from the bottom of the salt tower 2, the vapor mixture without aluminum chloride enters the high-efficiency rectifying tower 3 from the top of the salt tower 2, m-dichlorobenzene is continuously extracted from the top of the high-efficiency rectifying tower 3, the flow rate of the extracted material is 31g/h, and the contents of the extracted material are 14.3% of m-dichlorobenzene, 15.2% of p-dichlorobenzene and 1.5% of o-dichlorobenzene.

Wherein the operation reflux ratio of the high-efficiency rectifying tower 3 is 15, and reflux liquid returns to the stirring reactor 1 from the bottom of the high-efficiency rectifying tower 3; the salt tower 2 is provided with a heating and heat-preserving device such as a jacket and the like, and the theoretical plate number of the high-efficiency rectifying tower 3 is 71; the residence time of the vapor mixture in the salt tower was 11 seconds.

1111g of m-dichlorobenzene is cumulatively extracted from the top of the high-efficiency rectifying tower 3, the catalyst in the stirring reactor 1 needs to be replaced, and the solid sodium chloride in the salt tower 2 is supplemented.

Example 9

Method and device for continuously preparing m-dichlorobenzene

251g of mixed dichlorobenzene, 61g of aluminum chloride and 31g of lithium chloride are filled into a stirring reactor 1, the continuous feeding flow F is 31g/h of mixed dichlorobenzene, the weight ratio of o-dichlorobenzene to p-dichlorobenzene in the mixed dichlorobenzene is 1:1, hydrogen chloride gas is continuously fed in, and the reaction temperature (boiling point temperature) is 115 ℃; the vapor mixture vaporized from the stirring reactor 1 enters a salt tower 2, the operating temperature of the salt tower 2 is 115 ℃, and the complex NaAlCl formed is₄The molten salt is discharged from the bottom of the salt tower 2, the vapor mixture without aluminum chloride enters the high-efficiency rectifying tower 3 from the top of the salt tower 2, m-dichlorobenzene is continuously extracted from the top of the high-efficiency rectifying tower 3, the flow rate of the extracted material is 31g/h, and the contents of the extracted material are 14.7% of m-dichlorobenzene, 14.5% of p-dichlorobenzene and 1.1% of o-dichlorobenzene.

Wherein the operation reflux ratio of the high-efficiency rectifying tower 3 is 17, and reflux liquid returns to the stirring reactor 1 from the bottom of the high-efficiency rectifying tower 3; the salt tower 2 is provided with a heating and heat-preserving device such as a jacket and the like, and the theoretical plate number of the high-efficiency rectifying tower 3 is 11; the residence time of the vapor mixture in the salt tower was 151 seconds.

1411g of m-dichlorobenzene is cumulatively extracted from the top of the high-efficiency rectifying tower 3, the catalyst in the stirring reactor 1 needs to be replaced, and the solid sodium chloride in the salt tower 2 is supplemented.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.