阅读说明：本技术 一种催化选择性制备2,4’-二羟基二苯砜的方法 (Method for preparing 2,4' -dihydroxydiphenyl sulfone by catalytic selectivity ) 是由 骆建轻 周以鸿 程龙进 赖立冬 殷栎 于 2021-08-21 设计创作，主要内容包括：本发明公开了一种催化选择性制备2,4～(,)-二羟基二苯砜的方法,包括以下步骤,S1：向三口烧瓶内加入苯酚、高沸点有机溶剂和磁性纳米粒子负载的离子液体催化剂搅拌,获得第一混合液；S2：将第一混合液加热至100-145℃后添加浓硫酸,加毕体系回流分水至反应结束,获得第三混合液；S3：向第三混合液加入苯酚溶解,溶解结束后,回收纳米磁性负载的离子液体催化剂,将混合液降温至7-12℃析晶,体系过滤,滤饼用甲醇水洗涤得2,4～(,)-二羟基二苯砜粗品；S4：利用20-40％甲醇水溶液精制粗品得2,4～(,)-二羟基二苯砜。本发明加入磁性粒子负载的离子液体催化剂,在反应中,改变异变体的选择性,使苯酚和浓硫酸反应主要生成物2,4～(,)-二羟基二苯砜。(The invention discloses a catalytic selective preparation method of 2,4 ， -dihydroxydiphenyl sulfone, comprising the following step, S1: adding phenol, a high-boiling-point organic solvent and a magnetic nanoparticle-loaded ionic liquid catalyst into a three-neck flask, and stirring to obtain a first mixed solution; s2: heating the first mixed solution to the temperature of 100-145 ℃, adding concentrated sulfuric acid, and refluxing the water distribution of the added system until the reaction is finished to obtain a third mixed solution; s3: adding phenol into the third mixed solution for dissolving, recovering the nano magnetic loaded ionic liquid catalyst after the dissolving is finished, cooling the mixed solution to 7-12 ℃ for crystallization, filtering the system, and washing a filter cake with methanol water to obtain 2,4 ， -crude dihydroxydiphenylsulfone; s4: refining the crude product with 20-40% methanol water solution to obtain 2, 4% ， -dihydroxydiphenyl sulfone. The invention adds magnetic particlesThe sub-loaded ionic liquid catalyst changes the selectivity of variant in the reaction, so that the main products 2,4 are generated by the reaction of phenol and concentrated sulfuric acid ， -dihydroxydiphenyl sulfone.)

1. A method for preparing 2,4' -dihydroxy diphenyl sulfone by catalytic selectivity, which is characterized by comprising the following steps:

s1, adding 220 parts of phenol mixed solution and 3-6 parts of nano magnetically-loaded ionic liquid catalyst into a three-neck flask, and stirring to obtain a first mixed solution;

s2, heating the first mixed solution to the temperature of 100-;

s3, cooling the third mixed solution to 140-150 ℃, adding 65-85 parts of phenol into the third mixed solution for dissolving, recovering by using an external magnetic field after the dissolution is finished to obtain an ionic liquid catalyst and a filtrate loaded with magnetic nanoparticles, cooling the recovered filtrate to 7-12 ℃, crystallizing to obtain crystals, filtering, and washing a filter cake by using a methanol water solution to obtain a 2,4' -dihydroxy diphenyl sulfone crude product;

s4, refining the 2,4 '-dihydroxy diphenyl sulfone crude product by using a methanol water solution refining process to obtain the 2,4' -dihydroxy diphenyl sulfone.

2. The method for the catalytic selective preparation of 2,4' -dihydroxydiphenyl sulfone according to claim 1, wherein said step S1 is preceded by the further step of:

under the condition that the temperature is 20-30 ℃, firstly, stirring phenol and a high-boiling point solvent, wherein the mass ratio of the phenol to the high-boiling point solvent is 1:1, and stirring to obtain the phenol mixed solution.

3. The process according to claim 2, wherein the high boiling point solvent is a mixture of one or more of trimethylbenzene and m-dichlorotoluene.

4. The method for selectively preparing 2,4' -dihydroxydiphenyl sulfone according to claim 2, wherein in step S2, after the reflux reaction for 2-5min, the mixed gas of helium and nitrogen is introduced into the mixed solution.

5. The method for the catalytic selective preparation of 2,4' -dihydroxydiphenyl sulfone according to claim 1, wherein the preparation method of the magnetic nanoparticle-supported ionic liquid catalyst comprises:

a: mixing and stirring 10-16 parts of 3-chloropropyl-triethoxysilane, 3-4 parts of imidazole and 40-65 parts of toluene, introducing nitrogen gas for reflux reaction for 4-8 hours to obtain a first intermediate;

b: adding 200-310 parts of magnetic nanoparticles into the first intermediate to perform reflux reaction for 5-24h, and collecting the magnetic part by using a magnet after the reaction is finished to obtain a second intermediate;

c: adding 0.1-1 part of chloropropylamine into the second intermediate to perform a reflux reaction for 4-12h, continuously adding toluene into the second intermediate during the reaction, and collecting a magnetic part by using a magnet after the reaction is finished to obtain a third intermediate;

d: carrying out reflux reaction on the third intermediate and 0.1-1 part of 2-aldehyde pyridine for 4-12h, continuously adding toluene into the second intermediate during the reaction, cooling to room temperature after the reaction is finished, and collecting a magnetic part by using a magnet to obtain a fourth intermediate;

e: stirring the fourth intermediate and 0.1-1 part of palladium acetate to perform reflux reaction for 2-8h, continuously adding acetone into the second intermediate during the reaction, collecting a magnetic part by using a magnet after the reaction is finished, and washing and drying at 80 ℃ under a vacuum condition to obtain the magnetic nanoparticle-loaded ionic liquid catalyst.

6. The method of claim 5, wherein step b further comprises:

adding magnetic nano particles into the first intermediate body for reaction for 5-8min, then adding 1-3 parts of ethylenediamine tetraacetic acid, stirring until the reaction is finished, and collecting magnetic parts by using a magnet to obtain a second intermediate, wherein the second intermediate is a final product.

7. The method for the catalytic selective preparation of 2,4' -dihydroxydiphenyl sulfone according to claim 5, wherein the nano-magnetic particle preparation step comprises:

mixing and stirring 50-70 parts of ferric chloride and 15-25 parts of nitric acid solution to obtain magnetic mixed solution, adding 20-40 parts of sodium hydroxide solution and 10-15 parts of complexing agent into the magnetic mixed solution, stirring at high speed for 10-20min, and performing magnetic separation to obtain nano-magnetic F₃O₄。

8. The method of claim 7, wherein the magnetic separation to obtain nanomagnetic F is performed to obtain 2,4' -dihydroxydiphenyl sulfone₃O₄Comprises the following steps:

washing the nano magnetic particles obtained by magnetic separation with clear water for 2 times, washing with ethanol solution for 1 time, drying for 10-15min, calcining the dried nano magnetic particles, and calcining for 2h in the mixed atmosphere of nitrogen and helium to obtain the nano magnetic F₃O₄。

9. The method of claim 8, wherein the calcining step comprises:

and calcining the dried nano magnetic particles for 2 hours in a mixed atmosphere of nitrogen and helium, wherein the calcining temperature is 350-550 ℃.

10. The process for the catalytic selective preparation of 2,4' -dihydroxydiphenyl sulfone according to claim 7, wherein the complexing agent is sodium pyrophosphate or sodium hexametaphosphate.

Technical Field

The invention relates to a preparation method of a compound, in particular to a method for preparing 2,4' -dihydroxydiphenyl sulfone by catalytic selectivity.

Background

2,4' -dihydroxydiphenyl sulfone (abbreviated as 2,4' -BPS), english name 2,4' -sulfophenylenedienol, CAS number: 5397-34-2, white powder; density: 1.432g/cm 3; melting point: 184 ℃. It can be used not only as lubricant for tanning and metal processing, and as bactericide, but also as developer for thermosensitive recording paper. Because of excellent light resistance, oil resistance and adsorption resistance, the color rendering property of the composite material is better than that of the common 4,4 '-dihydroxy diphenyl sulfone (4, 4' -BPS for short). The existing method for preparing 2,4' -BPS mainly focuses on purifying 4, 4' -BPS and 2,4' -BPS isomers, and the operation method is very complicated, has low yield and cannot expand the capacity, thereby restricting the application of the method. Therefore, it is important to develop a method for directly and selectively preparing 2,4' -dihydroxydiphenyl sulfone.

Disclosure of Invention

In order to solve the above defects of the prior art, the invention provides a method for preparing 2,4' -dihydroxydiphenyl sulfone by catalytic selectivity, which comprises the following steps:

s1, adding 220 parts of phenol mixed solution and 3-6 parts of magnetic nanoparticle loaded ionic liquid catalyst into a three-neck flask, and stirring to obtain a first mixed solution;

s2, heating the first mixed solution to the temperature of 100-;

s3, cooling the third mixed solution to 140-150 ℃, adding 65-85 parts of phenol into the third mixed solution for dissolving, recovering by using an external magnetic field after the dissolution is finished to obtain the ionic liquid catalyst and filtrate loaded by the magnetic nanoparticles, cooling the recovered filtrate to 7-12 ℃ for crystallization, filtering, and washing the crystals by using methanol aqueous solution to obtain a 2, 4-dihydroxy diphenyl sulfone crude product;

because the ionic liquid catalyst loaded by the magnetic nanoparticles is insoluble in phenol, the ionic liquid catalyst loaded by the magnetic nanoparticles is separated from the filtrate by using a magnet;

s4, refining the 2,4 '-dihydroxy diphenyl sulfone crude product by using a methanol water solution refining process to obtain the 2,4' -dihydroxy diphenyl sulfone.

Preferably, step S1 is preceded by:

under the condition that the temperature is 20-30 ℃, firstly, stirring phenol and a high-boiling point solvent, wherein the mass ratio of the phenol to the high-boiling point solvent is 1:1, and stirring to obtain a phenol mixed solution.

Preferably, the high boiling point solvent is trimethylbenzene, m-dichlorotoluene or a mixture of the trimethylbenzene and the m-dichlorotoluene, and the high boiling point organic solvent is added, so that the temperature can be effectively controlled, and simultaneously, water generated in the reaction can be brought out through refluxing and water splitting, so that the consumption of phenol is reduced, and the yield of the crude 2,4' -dihydroxydiphenyl sulfone is improved.

Preferably, the preparation method of the magnetic nanoparticle-supported ionic liquid catalyst comprises the following steps:

a: mixing and stirring 10-16 parts of 3-chloropropyl-triethoxysilane, 3-4 parts of imidazole and 40-65 parts of toluene, introducing nitrogen gas for reflux reaction for 4-8 hours to obtain a first intermediate;

b: adding 200-310 parts of magnetic nanoparticles into the first intermediate to perform reflux reaction for 5-24h, and collecting the magnetic part by using a magnet after the reaction is finished to obtain a second intermediate;

c: adding 0.1-1 part of chloropropylamine into a second intermediate to perform a reflux reaction for 4-12h, continuously adding toluene into the second intermediate during the reaction, and collecting a magnetic part by using a magnet after the reaction is finished to obtain a third intermediate;

d: carrying out reflux reaction on the third intermediate and 0.1-1 part of 2-aldehyde pyridine for 4-12h, continuously adding toluene into the second intermediate during the reaction, cooling to room temperature after the reaction is finished, and collecting a magnetic part by using a magnet to obtain a fourth intermediate;

e: stirring the fourth intermediate and 0.1-1 part of palladium acetate to perform reflux reaction for 2-8h, continuously adding acetone into the second intermediate during the reaction, collecting magnetic parts by using a magnet after the reaction is finished, and washing and drying at 80 ℃ under a vacuum condition to obtain the nano magnetically-loaded ionic liquid catalyst.

The catalyst has the following chemical formula:

the reaction equation of the catalyst is as follows:

preferably, step b further comprises:

adding magnetic nano particles into the first intermediate body for reaction for 5-8min, then adding 1-3 parts of ethylenediamine tetraacetic acid, stirring until the reaction is finished, collecting the magnetic part by using a magnet to obtain a second intermediate, wherein the second intermediate is a final product, the ethylenediamine tetraacetic acid can be used as a complexing agent and can also be used as a pH value regulator, and the pH value is controlled to be 6-10.

Preferably, in step S2, after the reflux reaction is performed for 2 to 5min, a mixed gas of helium and nitrogen is introduced into the mixed solution, the helium is an inert gas, the helium has a small surface tension and a strong thermal conductivity, and the reaction rate of concentrated sulfuric acid and phenol can be increased by matching with nitrogen.

Preferably, the magnetic nanoparticle preparation step comprises:

mixing and stirring 50-70 parts of ferric chloride and 15-25 parts of nitric acid solution to obtain a magnetic mixed solution;

adding 20-40 parts of sodium hydroxide solution and 10-15 parts of complexing agent into the magnetic mixed solution, stirring at high speed for 10-20min, and performing magnetic separation to obtain magnetic nanoparticles F₃O₄。

Preferably, the separation is magneticObtaining magnetic nanoparticles F₃O₄Comprises the following steps:

washing the magnetic nanoparticles obtained by magnetic separation with clear water for 2 times, washing with ethanol solution for 1 time, drying for 10-15min, calcining the dried magnetic nanoparticles in the mixed atmosphere of nitrogen and helium for 2h at the calcining temperature of 350-550 ℃ to obtain magnetic nanoparticles F₃O₄。

Preferably, the complexing agent is sodium pyrophosphate or sodium hexametaphosphate, and both the sodium pyrophosphate and the sodium hexametaphosphate have strong complexing ability with Fe ions and can absorb redundant moisture.

The method is characterized in that the ionic liquid catalyst loaded with the magnetic nanoparticles is added in the reaction of phenol and concentrated sulfuric acid, the selectivity of a variant is changed in the reaction, the reaction product of the phenol and the concentrated sulfuric acid is 2,4 '-dihydroxy diphenyl sulfone, the yield of the 2,4' -dihydroxy diphenyl sulfone is increased, the ionic liquid catalyst loaded with the magnetic nanoparticles can be recovered by an external magnetic field after the reaction, the recovered ionic liquid catalyst loaded with the magnetic nanoparticles can still be continuously put into the reaction, and the 2,4 '-dihydroxy diphenyl sulfone generated by the reaction of the ionic liquid catalyst loaded with the magnetic nanoparticles can be repeatedly utilized without influencing the yield of the 2,4' -dihydroxy diphenyl sulfone.

Compared with the prior art, the invention has the beneficial effects that: adding an ionic liquid catalyst loaded by magnetic nano particles, and changing the selectivity of a variant in the reaction to ensure that the reaction product of phenol and concentrated sulfuric acid is 2,4' -dihydroxy diphenyl sulfone.

Drawings

FIG. 1 is a graph of the reaction rate of phenol and concentrated sulfuric acid.

FIG. 2 is a graph of the reaction rate for the production of intermediate 2.

Detailed Description

The invention is described in detail below with reference to the figures and examples.

Example 1

The invention provides a method for preparing 2,4' -dihydroxy diphenyl sulfone by catalytic selectivity, which comprises the following steps,

s1, under the condition that the temperature is 20 ℃, firstly stirring phenol and a high-boiling point solvent, wherein the mass ratio of the phenol to the high-boiling point solvent is 1:1, stirring to obtain a phenol mixed solution, the high-boiling point solvent is a mixture of trimethylbenzene and m-dichlorotoluene, the mass ratio of the trimethylbenzene to the m-dichlorotoluene is 1:1, adding 200 parts of the phenol mixed solution and 3 parts of a magnetic nanoparticle-loaded ionic liquid catalyst into a three-neck flask, and stirring to obtain a first mixed solution;

s2, heating the first mixed solution to 100 ℃, adding concentrated sulfuric acid into the first mixed solution, wherein the molar ratio of the concentrated sulfuric acid to phenol in the mixed solution is 1:2.0, obtaining a second mixed solution, heating the temperature of the second mixed solution to 170 ℃, performing reflux water diversion reaction, after performing reflux reaction for 2min, introducing a mixed gas of helium and nitrogen into the mixed solution, continuing performing reflux water diversion reaction, and after reacting for 12h, obtaining a third mixed solution;

s3, cooling the third mixed solution to 140 ℃, adding 65 parts of phenol into the third mixed solution to dissolve, recovering (attaching a magnet to the outer surface of a three-neck flask, sucking out liquid by using a suction pump to achieve the separation effect) by using an external magnetic field after the dissolution is finished to obtain the ionic liquid catalyst and filtrate loaded with the magnetic nanoparticles, cooling the recovered filtrate to 7 ℃ for crystallization, filtering, and washing a filter cake by using methanol water to obtain a 2,4' -dihydroxy diphenyl sulfone crude product;

s4, obtaining the 2,4' -dihydroxy diphenyl sulfone by using a methanol water solution refining process of the 2,4' -dihydroxy diphenyl sulfone crude product, wherein the refining process comprises the steps of heating and dissolving the 2,4' -dihydroxy diphenyl sulfone crude product in a methanol water solution, wherein the concentration of methanol is about 20%, and then cooling and precipitating a product.

The preparation method of the nano magnetic supported ionic liquid catalyst comprises the following steps:

a: mixing and stirring 10 parts of 3-chloropropyl-triethoxysilane, 3 parts of imidazole and 40 parts of toluene, introducing nitrogen gas for reflux reaction for 4 hours to obtain a first intermediate;

b: adding 200 parts of magnetic nanoparticles into the first intermediate to perform reflux reaction, adding 1 part of ethylenediamine tetraacetic acid after 5min of reaction, stirring until the reaction is finished, wherein the reflux reaction time is 5h, and collecting the magnetic part by using a magnet after the reaction is finished to obtain a second intermediate;

c: adding 0.1 part of chloropropylamine into a second intermediate to perform a reflux reaction, wherein the reaction time is 4h, continuously adding toluene into the second intermediate during the reaction, and collecting a magnetic part by using a magnet after the reaction is finished to obtain a third intermediate;

d: carrying out reflux reaction on the third intermediate and 0.1 part of 2-aldehyde pyridine for 4 hours, continuously adding toluene into the second intermediate during the reaction, cooling to room temperature after the reaction is finished, and collecting a magnetic part by using a magnet to obtain a fourth intermediate;

e: stirring the fourth intermediate and 0.1 part of palladium acetate to perform reflux reaction, wherein the reaction time is 2h, continuously adding acetone into the second intermediate during the reaction, collecting a magnetic part by using a magnet after the reaction is finished, and washing and drying under the vacuum condition of 80 ℃ to obtain the magnetic nanoparticle-loaded ionic liquid catalyst.

The magnet collection method is consistent with the method of recovering the magnetic nanoparticle-supported ionic liquid catalyst in step S3.

The preparation method of the magnetic nanoparticles comprises the following steps:

mixing and stirring 50 parts of ferric chloride and 15 parts of nitric acid solution to obtain a magnetic mixed solution;

adding 20 parts of sodium hydroxide solution and 10 parts of complexing agent and sodium pyrophosphate as complexing agent into the magnetic mixed solution, stirring at high speed, after 10min and magnetic separation, cleaning the magnetic part with clear water for 2 times, then washing with ethanol solution for 1 time, drying for 10min after washing, calcining the dried magnetic nanoparticles for 2h under the mixed atmosphere of nitrogen and helium to obtain magnetic nanoparticles F₃O₄。

Example 2

A method for preparing 2,4' -dihydroxydiphenyl sulfone by catalytic selectivity comprises the following steps,

s1, stirring phenol and a high-boiling-point solvent at the temperature of 24 ℃, wherein the mass ratio of the phenol to the high-boiling-point solvent is 1:1, stirring to obtain a phenol mixed solution, the high-boiling-point solvent is a mixture of trimethylbenzene and m-dichlorotoluene, the mass ratio of the trimethylbenzene to the m-dichlorotoluene is 1:1, adding 217 parts of the phenol mixed solution and 5 parts of a nano magnetically-loaded ionic liquid catalyst into a three-neck flask, and stirring to obtain a first mixed solution;

s2, heating the first mixed solution to 125 ℃, adding concentrated sulfuric acid into the first mixed solution, wherein the molar ratio of the concentrated sulfuric acid to phenol in the mixed solution is 1:2.1, obtaining a second mixed solution, heating the temperature of the second mixed solution to 180 ℃, performing reflux water diversion reaction, after 3min of reflux reaction, introducing mixed gas of helium and nitrogen into the mixed solution, continuing performing reflux water diversion reaction, and after 12h of reaction, obtaining a third mixed solution;

s3, cooling the third mixed solution to 147 ℃, adding 70 parts of phenol into the third mixed solution for dissolving, recovering (attaching a magnet to the outer surface of a three-neck flask, pouring out liquid) by using an external magnetic field after the dissolution is finished to obtain the ionic liquid catalyst and filtrate loaded with the magnetic nanoparticles, cooling the recovered filtrate to 10 ℃ for crystallization, filtering, and washing a filter cake with methanol water to obtain a 2, 4-dihydroxy diphenyl sulfone crude product;

s4, obtaining the 2,4' -dihydroxy diphenyl sulfone by using a methanol water solution refining process of the 2,4' -dihydroxy diphenyl sulfone crude product, wherein the refining process comprises the steps of heating and dissolving the 2,4' -dihydroxy diphenyl sulfone crude product in a methanol water solution, wherein the concentration of methanol is about 20%, and then cooling and precipitating a product.

The preparation method of the magnetic nanoparticle supported ionic liquid catalyst comprises the following steps:

a: mixing and stirring 12 parts of 3-chloropropyl-triethoxysilane, 3.5 parts of imidazole and 50 parts of toluene, introducing nitrogen gas for reflux reaction for 7.4 hours to obtain a first intermediate;

b: adding 250 parts of magnetic nanoparticles into the first intermediate to perform reflux reaction, adding 1.5 parts of ethylenediamine tetraacetic acid after 5-8min of reaction, stirring until the reaction is finished, wherein the reflux reaction time is 12h, and collecting the magnetic part by using a magnet after the reaction is finished to obtain a second intermediate;

c: adding 0.6 part of chloropropylamine into a second intermediate to perform a reflux reaction, wherein the reaction time is 11h, continuously adding toluene into the second intermediate during the reaction, and collecting a magnetic part by using a magnet after the reaction is finished to obtain a third intermediate;

d: carrying out reflux reaction on the third intermediate and 0.55 part of 2-aldehyde pyridine for 11h, continuously adding toluene into the second intermediate during the reaction, cooling to room temperature after the reaction is finished, and collecting a magnetic part by using a magnet to obtain a fourth intermediate;

e: stirring the fourth intermediate and 0.7 part of palladium acetate to perform reflux reaction, wherein the reaction time is 6h, continuously adding acetone into the second intermediate during the reaction, collecting a magnetic part by using a magnet after the reaction is finished, and washing and drying under the vacuum condition of 80 ℃ to obtain the magnetic nanoparticle-loaded ionic liquid catalyst.

The magnet collection method is consistent with the method of recovering the magnetic nanoparticle-supported ionic liquid catalyst in step S3.

The preparation method of the magnetic nanoparticles comprises the following steps:

mixing and stirring 56 parts of ferric chloride and 18 parts of nitric acid solution to obtain a magnetic mixed solution;

adding 29 parts of sodium hydroxide solution and 12 parts of complexing agent and sodium pyrophosphate as complexing agent into the magnetic mixed solution, stirring at high speed, performing magnetic separation after 10-20min, cleaning the magnetic part with clear water for 2 times, washing with ethanol solution for 1 time, drying for 12min after washing, calcining the dried magnetic nanoparticles for 2h under the mixed atmosphere of nitrogen and helium to obtain magnetic nanoparticles F₃O₄。

Example 3

A method for preparing 2,4' -dihydroxydiphenyl sulfone by catalytic selectivity comprises the following steps,

s1, stirring phenol and a high-boiling-point solvent at the temperature of 30 ℃, wherein the mass ratio of the phenol to the high-boiling-point solvent is 1:1, stirring to obtain a phenol mixed solution, the high-boiling-point solvent is a mixture of trimethylbenzene and m-dichlorotoluene, the mass ratio of the trimethylbenzene to the m-dichlorotoluene is 1:1, adding 220 parts of the phenol mixed solution and 6 parts of a nano magnetically-loaded ionic liquid catalyst into a three-neck flask, and stirring to obtain a first mixed solution;

s2, heating the first mixed solution to 145 ℃, adding concentrated sulfuric acid into the first mixed solution, wherein the molar ratio of the concentrated sulfuric acid to phenol in the mixed solution is 1:2.2, obtaining a second mixed solution, heating the second mixed solution to 200 ℃, performing reflux water diversion reaction, after the reflux reaction is performed for 5min, introducing mixed gas of helium and nitrogen into the mixed solution, continuing performing the reflux water diversion reaction, and after the reflux reaction is performed for 12h, obtaining a third mixed solution;

s3, cooling the third mixed solution to 150 ℃, adding 85 parts of phenol into the third mixed solution for dissolving, recovering (attaching a magnet to the outer surface of a three-neck flask, pouring out liquid) by using an external magnetic field after the dissolution is finished to obtain the ionic liquid catalyst and filtrate loaded with the magnetic nanoparticles, cooling the recovered filtrate to 12 ℃, crystallizing, filtering, and washing a filter cake with methanol water to obtain a 2,4' -dihydroxy diphenyl sulfone crude product;

s4, obtaining the 2,4' -dihydroxy diphenyl sulfone by using a methanol water solution refining process of the 2,4' -dihydroxy diphenyl sulfone crude product, wherein the refining process comprises the steps of heating and dissolving the 2,4' -dihydroxy diphenyl sulfone crude product in a methanol water solution, wherein the concentration of methanol is about 20%, and then cooling and precipitating a product.

The preparation method of the magnetic nanoparticle supported ionic liquid catalyst comprises the following steps:

a: mixing and stirring 16 parts of 3-chloropropyl-triethoxysilane, 4 parts of imidazole and 65 parts of toluene, introducing nitrogen gas for reflux reaction for 8 hours to obtain a first intermediate;

b: adding 310 parts of magnetic nanoparticles into the first intermediate to perform reflux reaction, adding 1-3 parts of ethylenediamine tetraacetic acid after 8min of reaction, stirring until the reaction is finished, wherein the reflux reaction time is 24h, and collecting the magnetic part by using a magnet after the reaction is finished to obtain a second intermediate;

c: adding 1 part of chloropropylamine into a second intermediate to perform a reflux reaction, wherein the reaction time is 12h, continuously adding toluene into the second intermediate during the reaction, and collecting a magnetic part by using a magnet after the reaction is finished to obtain a third intermediate;

d: carrying out reflux reaction on the third intermediate and 1 part of 2-aldehyde pyridine for 12h, continuously adding toluene into the second intermediate during the reaction, cooling to room temperature after the reaction is finished, and collecting a magnetic part by using a magnet to obtain a fourth intermediate;

e: stirring the fourth intermediate and 1 part of palladium acetate to perform reflux reaction for 8 hours, continuously adding acetone into the second intermediate during the reaction, collecting a magnetic part by using a magnet after the reaction is finished, and washing and drying the magnetic part under the vacuum condition of 80 ℃ to obtain the magnetic nanoparticle-loaded ionic liquid catalyst.

The magnet collection method is consistent with the method of recovering the magnetic nanoparticle-supported ionic liquid catalyst in step S3.

The preparation method of the magnetic nanoparticles comprises the following steps:

mixing and stirring 70 parts of ferric chloride and 25 parts of nitric acid solution to obtain a magnetic mixed solution;

adding 40 parts of sodium hydroxide solution and 15 parts of complexing agent and sodium pyrophosphate as complexing agent into the magnetic mixed solution, stirring at high speed, after 20min and magnetic separation, cleaning the magnetic part with clear water for 2 times, then washing with ethanol solution for 1 time, drying for 15min after washing, calcining the dried magnetic nanoparticles for 2h under the mixed atmosphere of nitrogen and helium to obtain magnetic nanoparticles F₃O₄。

Comparative example 1

This comparative example is substantially the same as example 2 except that:

in step S1, the phenol mixed solution and the magnetic nanoparticle-supported ionic liquid catalyst are not stirred, but the phenol and the magnetic nanoparticle-supported ionic liquid catalyst are directly stirred.

Comparative example 2

This comparative example is substantially the same as example 2 except that:

in step S1, the high boiling point solvent is not added to the phenol mixed solution and stirred.

Comparative example 3

This comparative example is substantially the same as example 2 except that:

in step S2, a mixed gas of helium and nitrogen is not introduced into the reflux water-splitting reaction.

Comparative example 4

This comparative example is substantially the same as example 2 except that:

and adding solid particles into the first intermediate for reflux reaction, and stirring without adding ethylenediamine tetraacetic acid.

Comparative example 5

This comparative example is substantially the same as example 2 except that:

the high boiling point solvent is m-dichlorotoluene.

Comparative example 6

This comparative example is substantially the same as example 2 except that:

the high boiling point solvent is trimethylbenzene.

Comparative example 7

This comparative example is substantially the same as example 2 except that:

the complexing agent is not added in the preparation method of the fixed particles.

2,4 '-dihydroxydiphenyl sulfone was prepared by the preparation methods of examples 1-3 and comparative example 1, wherein the content was measured by liquid chromatography, and the crude yield of 2,4' -dihydroxydiphenyl sulfone was measured by weighing, as shown in Table 1.

TABLE 1

As shown in table 1, the example liquid catalyst without magnetic nanoparticle support can only obtain a mixture of a small amount of 2,4' -dihydroxydiphenyl sulfone and a large amount of 4, 4' -dihydroxydiphenyl sulfone by directly reacting phenol with concentrated sulfuric acid, while the example liquid catalyst with magnetic nanoparticle support can improve the selectivity of 2,4' -isomer, so that 2,4' -dihydroxydiphenyl sulfone can be directly generated when phenol is reacted with concentrated sulfuric acid, the obtained content of 2,4' -dihydroxydiphenyl sulfone can be improved, and the subsequent purification steps can also be reduced, and after the reaction is finished, the ionic liquid catalyst with magnetic nanoparticle support can be recovered by using a magnet, the ionic liquid catalyst with magnetic nanoparticle support after recovery can be put into reaction again for use, and the specific data can be seen in table 2, therefore, the 2,4' -dihydroxy diphenyl sulfone prepared by the ionic liquid catalyst loaded by the magnetic nanoparticles has high content.

TABLE 2

As can be seen from the table 2, the magnetic nanoparticle supported ionic liquid catalyst can be reused, and as can be seen from the data in the table, the yield and purity of the crude 2,4 '-dihydroxydiphenyl sulfone product are not much different when the catalyst is used for the fourth time and the catalyst is used for the first time, so that the production cost is reduced while the yield of the 2,4' -dihydroxydiphenyl sulfone product is increased.

2,4 '-dihydroxy diphenyl sulfone prepared by putting the same weight of raw materials into the reaction by using the ionic liquid catalyst loaded with the magnetic nanoparticles prepared in examples 1-3, comparative example 2 and comparative example 7, and measuring the content by using a liquid chromatograph, and the crude yield of the 2,4' -dihydroxy diphenyl sulfone by using a weighing mode are shown in table 3.

TABLE 3

As can be seen from Table 3, the yield of the comparative examples without adding the high-boiling organic solvent is lower than that of examples 1-3, and the reaction requires high temperature, so that the addition of the high-boiling organic solvent can effectively control the temperature, and simultaneously, the water generated in the reaction can be taken away in the reflux water separation, thereby reducing the consumption of phenol and improving the yield of the crude product of 2,4' -dihydroxydiphenyl sulfone.

As can be seen from Table 3, in the preparation of immobilized particles, no complexing agent is added, so that the content of the prepared ionic liquid catalyst loaded on the magnetic nanoparticles is lower than that of the ionic liquid catalyst prepared in examples 1-3 and comparative example 2, thereby affecting the yield of the crude 2,4' -dihydroxydiphenyl sulfone.

The reaction rates of phenol and concentrated sulfuric acid were observed using the preparation methods of example 2 and comparative example 3, and specifically, see fig. 1.

As can be seen from FIG. 1, the reaction starts gradually and gradually gently in example 2 at 10h, while in comparative example 3 at 11h, so that the reaction is accelerated by introducing the mixed gas of helium and nitrogen during the reaction, and the reaction efficiency is accelerated.

The reaction rate of the intermediate 2 in the preparation of the magnetic nanoparticle-supported ionic liquid catalyst was observed by using the preparation methods of example 2 and comparative example 4, and is shown in fig. 2.

As shown in fig. 2, in comparative example 4, after the intermediate 1 is not added with the solid particles for the reflux reaction, the ethylenediamine tetraacetic acid is added and stirred, and the ethylenediamine tetraacetic acid can be used as a complexing agent to accelerate the generation of the intermediate 2. And the ethylene diamine tetraacetic acid can also be used as a regulator of the pH value to control the pH value during reaction.

Using the 2,4 '-dihydroxydiphenyl sulfone prepared in examples 1-3 and comparative examples 5-6, the crude yield of 2,4' -dihydroxydiphenyl sulfone was determined by weighing, as shown in Table 4.

As can be seen from Table 4, the yield of crude 2,4' -dihydroxydiphenyl sulfone was the highest when the high boiling solvent was a mixture of trimethylbenzene and m-dichlorotoluene.

The above additional technical features can be freely combined and used in superposition by those skilled in the art without conflict.

The above examples only show some embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the patent and protection scope of the present invention should be subject to the appended claims.