阅读说明：本技术 “一锅法”制备4,4′-二氯二苯砜的工艺 (Process for preparing 4,4' -dichlorodiphenyl sulfone by one-pot method ) 是由 王敏 李玉超 黄森彪 郭计儒 刘新新 郑艳霞 廖广明 左村村 于 2021-12-03 设计创作，主要内容包括：本发明属于4,4´-二氯二苯砜的制备技术领域,具体涉及一种“一锅法”制备4,4´-二氯二苯砜的工艺。所述的“一锅法”制备4,4´-二氯二苯砜的工艺：首先将氯苯、氯化亚砜和催化剂混合,通入氧气,反应结束,过滤分离,得到反应液和催化剂；然后将反应液降温结晶,析出4,4´-二氯二苯砜；最后将4,4´-二氯二苯砜后处理,得到高纯度4,4´-二氯二苯砜；其中催化剂重复利用。本发明提供一种“一锅法”制备4,4´-二氯二苯砜的工艺,制备步骤简单,催化剂制备简单,价格低廉,催化效率高,重复利用率高,制得4,4´-二氯二苯砜得纯度高。(The invention belongs to the technical field of preparation of 4,4 '-dichlorodiphenyl sulfone, and particularly relates to a process for preparing 4,4' -dichlorodiphenyl sulfone by a 'one-pot method'. The process for preparing 4,4' -dichlorodiphenyl sulfone by the one-pot method comprises the following steps: firstly, mixing chlorobenzene, thionyl chloride and a catalyst, introducing oxygen, finishing the reaction, and filtering and separating to obtain a reaction solution and the catalyst; then cooling and crystallizing the reaction solution to separate out 4,4' -dichlorodiphenyl sulfone; finally, carrying out aftertreatment on the 4,4 '-dichlorodiphenyl sulfone to obtain high-purity 4,4' -dichlorodiphenyl sulfone; wherein the catalyst is recycled. The invention provides a process for preparing 4,4 '-dichlorodiphenyl sulfone by a one-pot method, which has the advantages of simple preparation steps, simple catalyst preparation, low price, high catalytic efficiency and high repeated utilization rate, and the prepared 4,4' -dichlorodiphenyl sulfone has high purity.)

1. A process for preparing 4,4' -dichlorodiphenyl sulfone by a one-pot method is characterized by comprising the following steps: heating a mixed solution of chlorobenzene, thionyl chloride and a catalyst for one-step reaction for 1-10 hours at 40-150 ℃, introducing oxygen to keep the pressure at 0.1-2MPa, finishing the reaction, filtering and separating out the catalyst, cooling a reaction solution to-20-10 ℃, separating out a 4,4' -dichlorodiphenyl sulfone filter cake, cleaning and drying the separated 4,4' -dichlorodiphenyl sulfone filter cake, and continuously recrystallizing to obtain high-purity 4,4' -dichlorodiphenyl sulfone; wherein the catalyst is recycled;

the catalyst is a metal phosphomolybdate catalyst or a phosphomolybdic acid ionic liquid catalyst;

the preparation method of the metal phosphomolybdate catalyst comprises the following steps: dissolving ammonium molybdate in water, dropwise adding a phosphoric acid solution for reaction and reflux, cooling, adding metal salt for continuous reflux reaction, and drying and calcining the concentrated solution to obtain a metal phosphomolybdate catalyst;

the preparation method of the phosphomolybdic acid ionic liquid catalyst comprises the following steps: dissolving ammonium molybdate in water, dropwise adding a phosphoric acid solution, reacting and refluxing, concentrating, and then putting into a drying oven for drying and calcining to obtain phosphomolybdic acid; and (2) mixing and reacting halogenated alkane and methylimidazole, refluxing, adding a phosphomolybdic acid solution for reaction, filtering and drying to obtain the phosphomolybdic acid ionic liquid catalyst.

2. The "one-pot" process for the preparation of 4,4' -dichlorodiphenyl sulfone according to claim 1, wherein: the metal salt is one of sulfate, nitrate, chloride and bromide.

3. The "one-pot" process for the preparation of 4,4' -dichlorodiphenyl sulfone according to claim 1, wherein: the mass ratio of chlorobenzene to thionyl chloride was (1: 1) - (10: 1).

4. The "one-pot" process for the preparation of 4,4' -dichlorodiphenyl sulfone according to claim 1, wherein: the mass ratio of the total mass sum of the thionyl chloride and chlorobenzene to the catalyst is (1: 0.01) - (1: 1).

5. The "one-pot" process for the preparation of 4,4' -dichlorodiphenyl sulfone according to claim 1, wherein: the metal phosphomolybdate is iron phosphomolybdate.

Technical Field

The invention belongs to the technical field of preparation of 4,4 '-dichlorodiphenyl sulfone, and particularly relates to a process for preparing 4,4' -dichlorodiphenyl sulfone by a 'one-pot method'.

Background

4,4' -dichlorodiphenyl sulfone (DDS) is an important organic synthesis product, is a main raw material for preparing engineering plastics such as polysulfone, polyether sulfone and the like, and is also an intermediate of medicines, dyes, pesticides and the like. With the wide application of polymer materials, the demand of DDS is also increasing.

In the traditional sulfoxide oxidation method, hydrogen peroxide is used as an oxidant, concentrated sulfuric acid or an acetic acid mixture is mostly used as a catalyst for obtaining high-purity 4,4' -dichlorodiphenyl sulfone, but the use amount of acid is large, so that the equipment is highly corrosive; therefore, many studies have been made on the use of the catalyst.

CN201410765930.6 adopts a sulfoxide oxidation method, anhydrous aluminum trichloride is used as a catalyst to prepare DDS, but a large amount of corrosive acidic wastewater generated by the process is extremely difficult to treat, and the loss of aluminum chloride is serious.

CN202010249481.5 adopts a sulfoxide oxidation method, and a superparamagnetic nanoparticle-loaded ionic liquid is used as a catalyst to prepare DDS, the catalyst added with a magnetic substance is easy to separate from a reaction system, but the preparation process of the catalyst is complicated, and a byproduct is also generated in the DDS preparation process, so that the purity of 4,4' -dichlorodiphenyl sulfone is reduced.

CN201610086910.5 adopts phosphotungstic heteropoly acid quaternary ammonium salt as a catalyst, benzene as a solvent, hydrogen peroxide as an oxidant and the molar ratio of hydrogen peroxide to 4,4' -dichlorodiphenyl sulfoxide is 4-6: 1, 4' -dichlorodiphenyl sulfoxide is oxidized into 4,4' -dichlorodiphenyl sulfone, and the catalyst can be repeatedly used, but the preparation process of the catalyst is complicated, and the matched special quaternary ammonium salt phase transfer agent is expensive, so that the cost is considered, enterprises are limited in popularization and application, the use amount of hydrogen peroxide is large, and a strong carcinogenic substance benzene is used as the solvent, so that the yield of the product is low.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a process for preparing 4,4 '-dichlorodiphenyl sulfone by a one-pot method, the preparation steps are simple, the catalyst is simple to prepare, the price is low, the catalytic efficiency is high, the repeated utilization rate is high, and the purity of the prepared 4,4' -dichlorodiphenyl sulfone is high.

The invention relates to a process for preparing 4,4' -dichlorodiphenyl sulfone by a one-pot method, which comprises the following steps: firstly, heating a mixed solution of chlorobenzene, thionyl chloride and a catalyst to 40-150 ℃, reacting for 1-10 hours, introducing oxygen to keep the pressure at 0.1-2Mpa, filtering and separating out the catalyst after the reaction is finished, cooling and crystallizing the obtained reaction solution to-20-10 ℃, and continuously recrystallizing the separated 4,4 '-dichlorodiphenyl sulfone filter cake after cleaning and drying to obtain high-purity 4,4' -dichlorodiphenyl sulfone; wherein the catalyst is recycled.

The catalyst is a metal phosphomolybdate catalyst or a phosphomolybdic acid ionic liquid catalyst.

The preparation method of the metal phosphomolybdate catalyst comprises the following steps: dissolving ammonium molybdate in water, dropwise adding a phosphoric acid solution, and reacting and refluxing; and after the temperature is reduced, adding metal salt to continue reflux reaction, and drying and calcining the concentrated solution to obtain the metal phosphomolybdate catalyst.

The preparation method of the phosphomolybdic acid ionic liquid catalyst comprises the following steps: dissolving ammonium molybdate in water, dropwise adding a phosphoric acid solution, and reacting and refluxing; concentrating, drying in a drying oven, and calcining to obtain phosphomolybdic acid; and (2) mixing and reacting halogenated alkane and methylimidazole, refluxing, adding a phosphomolybdic acid solution for reaction, filtering and drying to obtain the phosphomolybdic acid ionic liquid catalyst.

The metal salt is one of sulfate, nitrate, chloride and bromide.

The mass ratio of chlorobenzene to thionyl chloride was (1: 1) - (10: 1).

The metal phosphomolybdate is iron phosphomolybdate.

The metal phosphomolybdate catalyst provided by the invention adjusts the acidity and the oxidation-reduction property of a reaction system, and shows a quasi-liquid phase behavior, and the catalyst provided by the invention has the acidity of B acid and simultaneously introduces the acidity of L acid by substituting hydrogen ions of heteropoly acid with metal cations, so that the purpose of dual acidity is achieved, and the catalyst becomes a green catalyst without environmental pollution; according to the phosphomolybdic acid ionic liquid catalyst adopted by the invention, ionic liquid is introduced into phosphomolybdic acid, so that the phosphomolybdic acid ionic liquid catalyst has different types and different strength of acid sites; and the adopted catalyst is a solid catalyst, so that the separation from a reaction system is facilitated, the generation of isomeric monomer 2,4 '-dichlorodiphenyl sulfone or 3, 4' -dichlorodiphenyl sulfone is reduced through the regulation and control of the catalyst, and the purity of the product is improved.

According to the preparation method, the metal phosphomolybdate catalyst or phosphomolybdic acid ionic liquid catalyst, chlorobenzene and thionyl chloride are mixed in one step, and the 4,4' -dichlorodiphenyl sulfone is prepared by a one-pot method, so that the production steps of the process are simplified, the process flow is shortened, and the safety coefficient is improved.

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

(1) the process for preparing 4,4' -dichlorodiphenyl sulfone by the one-pot method is improved to the one-pot method from a multi-step method, so that the process steps are shortened, the process flow is simplified, and the enterprise benefit is improved;

(2) according to the process for preparing 4,4 '-dichlorodiphenyl sulfone by the one-pot method, the preparation method of the catalyst is simple, the cost is low, the repeated utilization rate is high, the catalytic efficiency is high, the selectivity is high, the service life is long, and the purity of the prepared 4,4' -dichlorodiphenyl sulfone is high;

(3) the process for preparing 4,4' -dichlorodiphenyl sulfone by the one-pot method saves the consumption of hydrogen peroxide, reduces the danger coefficient, reduces the utilization of water resources and saves energy consumption;

(4) according to the process for preparing 4,4' -dichlorodiphenyl sulfone by the one-pot method, the catalyst is used without harm to equipment and pollution to the environment, so that the process becomes a green process and an environment-friendly process.

Drawings

FIG. 1 is a high performance liquid chromatogram of 4,4' -dichlorodiphenyl sulfone produced in example 1 of the present invention.

Detailed Description

The invention provides a process for preparing 4,4' -dichlorodiphenyl sulfone by a one-pot method, and a person skilled in the art can use the content of the text for reference and appropriately improve the process parameters to realize the process. It is expressly intended that all such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the scope and ambit of the invention. While the process of the present invention has been described in terms of preferred embodiments, it will be apparent to those skilled in the art that variations and appropriate modifications and combinations of the process of the present invention may be made to implement and use the techniques of the present invention without departing from the spirit and scope of the invention.

The invention relates to a process for preparing 4,4' -dichlorodiphenyl sulfone by a one-pot method, which comprises the following steps: the method comprises the following steps:

firstly, chlorobenzene, thionyl chloride and a catalyst are mixed in a high-pressure reaction kettle according to a proportion, oxygen with the pressure of 0.1-2MPa is introduced, the mixture reacts for 1-10 hours at the temperature of 40-150 ℃, and after the reaction is finished, the mixture is filtered and separated while the mixture is hot to obtain reaction liquid and the catalyst;

then cooling the reaction liquid to-20-10 ℃, crystallizing, and separating out 4,4' -dichlorodiphenyl sulfone;

finally, cleaning the 4,4 '-dichlorodiphenyl sulfone crystals with deionized water, drying at 50-100 ℃, and recrystallizing and purifying to obtain high-purity 4,4' -dichlorodiphenyl sulfone;

wherein the catalyst is recycled.

The catalyst is a metal phosphomolybdate catalyst or a phosphomolybdic acid ionic liquid catalyst, and the metal phosphomolybdate is iron phosphomolybdate.

Preferably, the preparation method of the metal phosphomolybdate catalyst comprises the following steps: dissolving 8mmol of ammonium heptamolybdate in water, heating to 85 ℃, dropwise adding 5mmol of 35% phosphoric acid solution, and heating to 110 ℃, and carrying out reaction reflux for 4 hours; and cooling to 85 ℃, adding 15mmol of metal salt, continuing reflux reaction, drying the solution concentrated at 85 ℃, and calcining at 360 ℃ for 12 hours to obtain the metal phosphomolybdate catalyst. Wherein the ratio of phosphoric acid: ammonium molybdate: the mass molar ratio of the metal salt is preferably: 7:12:7.

Preferably, the preparation method of the phosphomolybdic acid ionic liquid catalyst comprises the following steps: adding 8.7g (0.05 mol) of 1 methylimidazole and 6.65g (0.05 mol) of n-butyl chloride into a three-neck flask provided with a reflux condenser, stirring and reacting at 110 ℃ for 24 hours, taking out and cooling after the reaction is finished, repeatedly washing with equal volume of ethyl acetate, drying in vacuum, and removing residual ethyl acetate to obtain light yellow liquid, namely ionic liquid [ Bmim ] Cl;

the metal salt is one of sulfate, nitrate, chloride and bromide.

The mass ratio of chlorobenzene to thionyl chloride is (1: 1) - (10: 1), and the preferred ratio is (2.5: 1) - (10: 1).

The mass ratio of the total mass sum of thionyl chloride and chlorobenzene to the catalyst is (1: 0.01) - (1: 1), preferably (4: 1) - (10: 1).

In order to further illustrate the present invention, the process for preparing 4,4' -dichlorodiphenyl sulfone according to the "one-pot method" and the preparation of the catalyst according to the present invention will be described in detail with reference to the following examples.

Example 1

The preparation method of the iron phosphomolybdate catalyst comprises the following steps:

dissolving 10.5g (8 mmol) of ammonium heptamolybdate in 100mL of water, heating to 85 ℃, dropwise adding 1.42g (5 mmol) of 35% phosphoric acid solution within 15min, and carrying out oil bath reaction at 110 ℃ for refluxing for 5 h; and then cooling to 85 ℃, adding ferric nitrate, continuously reacting and refluxing for 3h, concentrating, drying in a drying oven at 85 ℃ for 12h, and calcining at 360 ℃ for 12h to obtain the iron phosphomolybdate catalyst.

The process for preparing 4,4' -dichlorodiphenyl sulfone by the one-pot method comprises the following steps:

placing 5.6g (50 mmol) of chlorobenzene, 1.19g (10 mmol) of thionyl chloride and 1.19g (0.66 mmol) of the iron phosphomolybdate in a high-pressure reaction kettle, introducing 0.7MPa of oxygen, reacting for 4 hours at 75 ℃, filtering the reaction solution after reaction while hot, and separating out a catalyst to obtain a mixed reaction solution of the chlorobenzene and 4,4' -dichlorodiphenyl sulfone;

then cooling the mixed reaction solution to-10 ℃, crystallizing, and separating out 4,4' -dichlorodiphenyl sulfone;

and finally, washing the filter cake filtered by the 4,4 '-dichlorodiphenyl sulfone crystal with deionized water, drying, and then recrystallizing and purifying to obtain the high-purity 4,4' -dichlorodiphenyl sulfone.

Example 2

The process for preparing 4,4' -dichlorodiphenyl sulfone by the one-pot method comprises the following steps:

placing 6.7g (60 mmol) of chlorobenzene, 2.38g (20 mmol) of thionyl chloride and 0.19g (0.66 mmol) of iron phosphomolybdate of example 1 in an autoclave, introducing 0.7MPa of oxygen, reacting at 75 ℃ for 4 hours, filtering the reaction solution after the reaction while hot, and separating the catalyst to obtain a mixed reaction solution of chlorobenzene and 4,4' -dichlorodiphenyl sulfone;

then cooling the mixed reaction solution to-10 ℃, crystallizing, and separating out 4,4' -dichlorodiphenyl sulfone;

and finally, washing the filter cake filtered by the 4,4 '-dichlorodiphenyl sulfone crystal with deionized water, drying, and then recrystallizing and purifying to obtain the high-purity 4,4' -dichlorodiphenyl sulfone.

Example 3

The process for preparing 4,4' -dichlorodiphenyl sulfone by the one-pot method comprises the following steps:

placing 11.2g (100 mmol) of chlorobenzene, 2.38g (20 mmol) of thionyl chloride and 1.36g (0.72 mmol) of iron phosphomolybdate of example 1 in an autoclave, introducing oxygen of 0.7MPa, reacting at 75 ℃ for 4 hours, filtering the reaction solution after the reaction while hot, and separating the catalyst to obtain a mixed reaction solution of chlorobenzene and 4,4' -dichlorodiphenyl sulfone;

then cooling the mixed reaction solution to-10 ℃, crystallizing, and separating out 4,4' -dichlorodiphenyl sulfone;

and finally, washing the filter cake filtered by the 4,4 '-dichlorodiphenyl sulfone crystal with deionized water, drying, and then recrystallizing and purifying to obtain the high-purity 4,4' -dichlorodiphenyl sulfone.

Example 4

The process for preparing 4,4' -dichlorodiphenyl sulfone by the one-pot method comprises the following steps:

placing 5.6g (50 mmol) of chlorobenzene and 5.95g (50 mmol) of thionyl chloride 1.15g (0.58 mmol) of the iron phosphomolybdate of example 1 in an autoclave, introducing 0.7MPa of oxygen, reacting at 75 ℃ for 4h, filtering the reaction solution after reaction while hot, and separating out the catalyst to obtain a mixed reaction solution of chlorobenzene and 4,4' -dichlorodiphenyl sulfone;

then cooling the mixed reaction solution to-10 ℃, crystallizing, and separating out 4,4' -dichlorodiphenyl sulfone;

and finally, washing the filter cake filtered by the 4,4 '-dichlorodiphenyl sulfone crystal with deionized water, drying, and then recrystallizing and purifying to obtain the high-purity 4,4' -dichlorodiphenyl sulfone.

Example 5

The process for preparing 4,4' -dichlorodiphenyl sulfone by the one-pot method comprises the following steps:

placing 5.6g (50 mmol) of chlorobenzene, 1.19g (10 mmol) of thionyl chloride and 1.19g (0.66 mmol) of the iron phosphomolybdate in a high-pressure reaction kettle, introducing 0.5MPa of oxygen, reacting at 75 ℃ for 4h, filtering the reaction solution after reaction while hot, and separating out a catalyst to obtain a mixed reaction solution of the chlorobenzene and 4,4' -dichlorodiphenyl sulfone;

then cooling the mixed reaction solution to-10 ℃, crystallizing, and separating out 4,4' -dichlorodiphenyl sulfone;

and finally, washing the filter cake filtered by the 4,4 '-dichlorodiphenyl sulfone crystal with deionized water, drying, and then recrystallizing and purifying to obtain the high-purity 4,4' -dichlorodiphenyl sulfone.

Example 6

The process for preparing 4,4' -dichlorodiphenyl sulfone by the one-pot method comprises the following steps:

placing 5.6g (50 mmol) of chlorobenzene, 1.19g (10 mmol) of thionyl chloride and 1.19g (0.66 mmol) of iron phosphomolybdate of example 1 in an autoclave, introducing 1MPa of oxygen, reacting at 75 ℃ for 4h, filtering the reaction solution after reaction while hot, and separating out the catalyst to obtain a mixed reaction solution of chlorobenzene and 4,4' -dichlorodiphenyl sulfone;

then cooling the mixed reaction solution to-10 ℃, crystallizing, and separating out 4,4' -dichlorodiphenyl sulfone;

and finally, washing the filter cake filtered by the 4,4 '-dichlorodiphenyl sulfone crystal with deionized water, drying, and then recrystallizing and purifying to obtain the high-purity 4,4' -dichlorodiphenyl sulfone.

Example 7

The preparation method of the phosphomolybdic acid ionic liquid catalyst comprises the following steps:

dissolving 10.5g (8 mmol) of ammonium heptamolybdate in 100mL of water, heating to 85 ℃, dropwise adding 1.42g (5 mmol) of 35% phosphoric acid solution within 15min, and carrying out oil bath reaction at 110 ℃ for refluxing for 5 h; then cooling to 85 ℃, concentrating, drying in a drying oven at 85 ℃ for 12h, and calcining at 360 ℃ for 12h after drying to obtain phosphomolybdic acid; mixing 8.21g (0.1 mol) of methylimidazole and 6.808g (0.1 mol) of n-butyl chloride in a three-neck flask, stirring, and carrying out reflux reaction at 150 ℃ for 2 hours to obtain [ Bmim ] Cl; dissolving 18.25g (10 mmol) of phosphomolybdic acid in water, heating to 30 ℃, adding 5.21g (30 mmol) [ Bmim ] Cl, heating to 85 ℃, reacting for 5h, concentrating, and drying for 6h to obtain the phosphomolybdic acid ionic liquid catalyst.

The process for preparing 4,4' -dichlorodiphenyl sulfone by the one-pot method comprises the following steps:

placing 5.6g (50 mmol) of chlorobenzene, 1.19g (10 mmol) of thionyl chloride and 1.19g (0.65 mmol) of the prepared phosphomolybdic acid ionic liquid catalyst in a high-pressure reaction kettle, introducing 0.7MPa of oxygen, reacting for 4 hours at 75 ℃, filtering the reaction liquid after reaction while hot, and separating out the catalyst to obtain a mixed reaction liquid of the chlorobenzene and 4,4' -dichlorodiphenyl sulfone;

then cooling the mixed reaction solution to-10 ℃, crystallizing, and separating out 4,4' -dichlorodiphenyl sulfone;

and finally, washing the filter cake filtered by the 4,4 '-dichlorodiphenyl sulfone crystal with deionized water, drying, and then recrystallizing and purifying to obtain the high-purity 4,4' -dichlorodiphenyl sulfone.

Example 8

The process for preparing 4,4' -dichlorodiphenyl sulfone by the one-pot method comprises the following steps:

placing 6.7g (60 mmol) of chlorobenzene, 1.19g (10 mmol) of thionyl chloride and 1.19g (0.65 mmol) of the phosphomolybdic acid ionic liquid catalyst prepared in example 7 in an autoclave, introducing 0.7MPa of oxygen, reacting at 75 ℃ for 4h, filtering the reaction solution after reaction while hot, and separating out the catalyst to obtain a mixed reaction solution of chlorobenzene and 4,4' -dichlorodiphenyl sulfone;

then cooling the mixed reaction solution to-10 ℃, crystallizing, and separating out 4,4' -dichlorodiphenyl sulfone;

and finally, washing the filter cake filtered by the 4,4 '-dichlorodiphenyl sulfone crystal with deionized water, drying, and then recrystallizing and purifying to obtain the high-purity 4,4' -dichlorodiphenyl sulfone.

Example 9

The process for preparing 4,4' -dichlorodiphenyl sulfone by the one-pot method comprises the following steps:

placing 5.6g (50 mmol) of chlorobenzene, 1.19g (10 mmol) of thionyl chloride and 1.19g (0.65 mmol) of the phosphomolybdic acid ionic liquid catalyst prepared in example 7 in an autoclave, introducing 0.5MPa of oxygen, reacting at 75 ℃ for 4h, filtering the reaction solution after reaction while hot, and separating out the catalyst to obtain a mixed reaction solution of the chlorobenzene and 4,4' -dichlorodiphenyl sulfone;

then cooling the mixed reaction solution to-10 ℃, crystallizing, and separating out 4,4' -dichlorodiphenyl sulfone;

and finally, washing the filter cake filtered by the 4,4 '-dichlorodiphenyl sulfone crystal with deionized water, drying, and then recrystallizing and purifying to obtain the high-purity 4,4' -dichlorodiphenyl sulfone.

Example 10

The process for preparing 4,4' -dichlorodiphenyl sulfone by the one-pot method comprises the following steps:

placing 5.6g (50 mmol) of chlorobenzene, 1.19g (10 mmol) of thionyl chloride and 1.19g (0.65 mmol) of the phosphomolybdic acid ionic liquid catalyst prepared in example 7 in an autoclave, introducing 1MPa of oxygen, reacting at 75 ℃ for 4 hours, filtering the reaction solution after the reaction while hot, and separating the catalyst to obtain a mixed reaction solution of chlorobenzene and 4,4' -dichlorodiphenyl sulfone;

then cooling the mixed reaction solution to-10 ℃, crystallizing, and separating out 4,4' -dichlorodiphenyl sulfone;

and finally, washing the filter cake filtered by the 4,4 '-dichlorodiphenyl sulfone crystal with deionized water, drying, and then recrystallizing and purifying to obtain the high-purity 4,4' -dichlorodiphenyl sulfone.

Example 11

The process for preparing 4,4' -dichlorodiphenyl sulfone by the one-pot method comprises the following steps:

placing 5.6g (50 mmol) of chlorobenzene, 1.19g (10 mmol) of thionyl chloride and 1.8g (1 mmol) of the phosphomolybdic acid ionic liquid catalyst prepared in example 7 in an autoclave, introducing 0.7MPa of oxygen, reacting at 75 ℃ for 4 hours, filtering the reaction solution after the reaction while hot, and separating the catalyst to obtain a mixed reaction solution of chlorobenzene and 4,4' -dichlorodiphenyl sulfone;

then cooling the mixed reaction solution to-10 ℃, crystallizing, and separating out 4,4' -dichlorodiphenyl sulfone;

and finally, washing the filter cake filtered by the 4,4 '-dichlorodiphenyl sulfone crystal with deionized water, drying, and then recrystallizing and purifying to obtain the high-purity 4,4' -dichlorodiphenyl sulfone.

Example 12

The process for preparing 4,4' -dichlorodiphenyl sulfone by the one-pot method comprises the following steps:

placing 5.6g (50 mmol) of chlorobenzene, 2.38g (20 mmol) of thionyl chloride and 1.19g (0.65 mmol) of the phosphomolybdic acid ionic liquid catalyst prepared in example 7 in an autoclave, introducing 0.7MPa of oxygen, reacting at 75 ℃ for 4h, filtering the reaction solution after reaction while hot, and separating out the catalyst to obtain a mixed reaction solution of the chlorobenzene and 4,4' -dichlorodiphenyl sulfone;

then cooling the mixed reaction solution to-10 ℃, crystallizing, and separating out 4,4' -dichlorodiphenyl sulfone;

and finally, washing the filter cake filtered by the 4,4 '-dichlorodiphenyl sulfone crystal with deionized water, drying, and then recrystallizing and purifying to obtain the high-purity 4,4' -dichlorodiphenyl sulfone.

Example 13

After the catalyst separated in example 6 was recycled six times according to the same conditions as in example 6, the prepared 4,4' -dichlorodiphenyl sulfone was collected and tested for purity and yield.

Example 14

After the catalyst separated in example 11 was recycled six times according to the same conditions as in example 11, the prepared 4,4' -dichlorodiphenyl sulfone was collected and tested for purity and yield.

Comparative example 1

A process for preparing 4,4' -dichlorodiphenyl sulfone comprises the following steps:

(1) adding 1.33g (10 mmol) of aluminum chloride into 5.6g (50 mmol) of chlorobenzene, uniformly stirring, adding 1.19g (10 mmol) of thionyl chloride at 30 ℃, heating to 75 ℃ and reacting for 4 hours;

(2) dropwise adding 10mL of distilled water into the reaction solution, and heating to 110 ℃;

(3) stirring for 1h, cooling to 0-5 ℃, separating out crystals, filtering, and drying at 75 ℃ for 12h to obtain 4,4' -dichlorodiphenyl sulfoxide;

(4) dissolving the sulfoxide intermediate product with a solvent of glacial acetic acid, adding 1g of 35% hydrogen peroxide for oxidation to obtain a crude product of 4,4 '-dichlorodiphenyl sulfone, and performing secondary oxidation refining on the crude product to obtain the 4,4' -dichlorodiphenyl sulfone.

Comparative example 2

A process for preparing 4,4' -dichlorodiphenyl sulfone comprises the following steps:

5.6g (50 mmol) of chlorobenzene, 1.19g (10 mmol) of thionyl chloride and 0.4mmol (1.19 g) of phosphotungstic acid (H)₃PW₁₂O₄₀) The method comprises the following steps of placing a catalyst in a high-pressure reaction kettle, introducing 1MPa oxygen, reacting for 4 hours at 75 ℃, filtering the reaction liquid after reaction while the reaction liquid is hot, and separating out the catalyst to obtain a mixed reaction liquid of chlorobenzene and 4,4' -dichlorodiphenyl sulfone;

then cooling the mixed reaction solution to-10 ℃, crystallizing, and separating out 4,4' -dichlorodiphenyl sulfone;

and finally, washing the filter cake filtered by the 4,4 '-dichlorodiphenyl sulfone crystal with deionized water, drying, and then performing recrystallization purification to obtain the 4,4' -dichlorodiphenyl sulfone.

Comparative example 3

A process for preparing 4,4' -dichlorodiphenyl sulfone comprises the following steps:

dissolving 2.7 g (10mmo1) of 4,4 '-dichlorodiphenyl sulfoxide in 20 mL of benzene, adding 0.27g of composite catalyst of tridemorph quaternary ammonium salt and phosphotungstic heteropoly acid 0.27g, dropwise adding 50% hydrogen peroxide 3mL at 90 ℃, stirring for reaction for 120 minutes, standing, cooling to room temperature, separating, filtering, concentrating an upper organic layer, separating, and drying to obtain 4,4' -dichlorodiphenyl sulfone.

Comparative example 4

A process for preparing 4,4' -dichlorodiphenyl sulfone comprises the following steps:

placing 1.12g (10 mmol) of chlorobenzene, 2.38g (20 mmol) of thionyl chloride and 1.8g (1 mmol) of iron phosphomolybdate of example 1 in a high-pressure reaction kettle, introducing 1MPa of oxygen, reacting at 75 ℃ for 4h, filtering the reaction solution after reaction while hot, and separating out a catalyst to obtain a mixed reaction solution of chlorobenzene and 4,4' -dichlorodiphenyl sulfone;

then cooling the mixed reaction solution to-10 ℃, crystallizing, and separating out 4,4' -dichlorodiphenyl sulfone;

and finally, washing the filter cake filtered by the 4,4 '-dichlorodiphenyl sulfone crystal with deionized water, drying, and then performing recrystallization purification to obtain the 4,4' -dichlorodiphenyl sulfone.

4,4' -dichlorodiphenyl sulfone prepared in the above examples 1 to 14 and comparative examples 1 to 4 was subjected to high performance liquid chromatography to examine its purity, and its yield and the kind of produced wastewater, the amount of water resources used were calculated. The results are shown in table 1:

TABLE 1 test results

As can be seen from the above table and the combined preparation method, although the 4,4' -dichlorodiphenyl sulfone prepared in comparative example 1 and comparative example 3 has high purity and yield, a large amount of mixed acid is applied, and the steps are complicated and require two different operation steps, so that the work efficiency is reduced, the operation difficulty is increased, the equipment maintenance and labor costs are increased, and the cost of wastewater treatment by a large amount of mixed acid is extremely harmful to the environment.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and should not be taken as limiting the scope of the embodiments of the present invention. The present invention is not limited to the above examples, and equivalent changes and modifications made by those skilled in the art within the spirit and scope of the present invention should be construed as being included in the scope of the present invention.