CN112321396B - Method for synthesizing hydroquinone through selective oxidation reduction of phenol - Google Patents

Abstract

This case involves a method for synthesizing hydroquinone by selective redox of phenol, which includes the following steps: adding an organic selenium catalyst containing carbon nanotubes, phenol and 30% hydrogen peroxide into a reaction flask, adding DMF, stirring evenly, filling with nitrogen, and sealing After the reaction at 60°C for 1-2 h, the filtrate and the solid were collected by filtration. The filtrate was subjected to rotary evaporation to remove DMF and then diluted with ethanol. Triisooctylamine was added to stir to precipitate p-benzoquinone from the ethanol, and p-benzoquinone was collected. Metal was added to the reaction flask. Catalyst and pyridine, the p-benzoquinone is added to the bottle, a hydrogen donor is added, and the mixture is heated and reacted for 1-2 hours; the reaction solution is concentrated, decoked, decolorized and crystallized to obtain hydroquinone. The present invention starts from phenol, utilizes a self-made organic selenium catalyst to prepare p-benzoquinone with high selectivity, and then catalyzes the hydrogenation and reduction of p-benzoquinone to hydroquinone through Pt/C, and can achieve high selectivity at medium and high temperature. At the same time, the conversion of p-benzoquinone can be almost complete.

Description

A kind of method for phenol selective redox synthesis hydroquinone

technical field

The invention relates to the technical field of hydroquinone synthesis, in particular to a method for synthesizing hydroquinone by selective oxidation and reduction of phenol.

Background technique

Phenol is a common basic chemical raw material with large output and low price, and p-benzoquinone is an intermediate in the synthesis of hydroquinone. When synthesizing hydroquinone from phenol, the selective oxidation of paraquinone is very important. Hydroquinone (Hydroquinone; HQ), also known as hydroquinone, is an important industrial intermediate. It is widely used in the preparation of electrode materials, photographic developers, anthraquinone and azo dyes, antioxidants in rubber and gasoline, as raw materials for the manufacture of dyes and pharmaceutical compounds, and in the preparation of biologically active natural products and functional materials such as polymers. Basic raw material for liquid crystals and other polymers.

At present, the most original way to synthesize hydroquinone is to form benzoquinone through the oxidation of aniline by _MnO2 and _H2SO4 aqueous solution, and then reduce the benzoquinone by iron powder or _{hydrogenation} , and finally obtain the product hydroquinone. However, this method inevitably leads to the generation of a large amount of solid waste that is difficult to handle, or the use of flammable and explosive gas hydrogen, which is potentially dangerous.

SUMMARY OF THE INVENTION

In view of the deficiencies in the prior art, the object of the present invention is to provide a kind of synthetic method of phenol high-selective redox to hydroquinone.

To achieve the above object, the present invention provides the following technical solutions:

A method for synthesizing hydroquinone by selective oxidation-reduction of phenol, comprising the steps:

S1: Add organic selenium catalyst containing carbon nanotubes, phenol and 30% hydrogen peroxide into the reaction flask, add N,N-dimethylformamide, stir evenly, fill with nitrogen, and react at 60°C for 1-2h after sealing;

S2: after the reaction is completed, the filtrate and the solid are collected by filtration, the filtrate is evaporated to remove N,N-dimethylformamide and then diluted with ethanol, followed by adding triisooctylamine to stir, so that p-benzoquinone is precipitated from ethanol, and p-benzene is collected. Quinone;

S3: add a metal catalyst and pyridine into a round-bottomed flask, add the p-benzoquinone to the flask, add a hydrogen donor, and heat the mixture at 80-100° C. for 1-2 hours;

S4: After the reaction is completed, the reaction solution is concentrated, decoked and decolorized to obtain hydroquinone.

Further, the carbon nanotube-containing organoselenium catalyst is 0.5-5 wt % of the mass of phenol, and the molar ratio of the hydrogen peroxide to the phenol is 1-3:1.

Further, the preparation steps of the carbon nanotube-containing organoselenium catalyst are as follows:

1) Add selenium powder to distilled water, introduce nitrogen and stir evenly, then add an aqueous solution of sodium borohydride, add an equal amount of selenium powder, heat up to 50-60°C, and react for 40-60min;

2) adding saturated sodium carbonate solution dropwise to the aqueous solution of 4-bromo-2,6-difluorobenzoic acid, adjusting pH to 9-10;

3) The alkaline solution of step 2) was added dropwise to step 1), and the reaction was stirred at room temperature for 24h;

4) filter after the reaction, adjust the pH of the filtrate to 3-4 with dilute hydrochloric acid, filter with suction, wash and dry with water, and recrystallize with ethyl acetate to obtain diselenide carboxylate;

5) Place the modified carbon nanotubes in a solvent, add the carboxylate diselenide, stir and reflux at 70-80° C. for 12-24 hours, filter, wash and dry to obtain an organic selenium catalyst containing carbon nanotubes .

Further, the molar ratio of the selenium powder to sodium borohydride and halogenated carboxylic acid is 1:1:1.

Further, the modified carbon nanotubes are hydroxylated double-walled carbon nanotubes, and the mass ratio of the modified carbon nanotubes to the carboxylate diselenide is 1:5-10.

Further, the metal catalyst is selected from a platinum catalyst, a copper catalyst, a nickel catalyst or a palladium catalyst.

Further, the hydrogen donor is selected from one of cyclohexanone, isopropanol, isooctanol or cyclohexanol.

Further, the molar ratio of p-benzoquinone to hydrogen donor and pyridine is 1:5-10:1%-5%.

The beneficial effects of the invention are as follows: the invention starts from phenol, the output of phenol is large and the price is low; the self-made organic selenium catalyst is used to prepare p-benzoquinone with high selectivity. It can rapidly catalyze the synthesis of p-benzoquinone from phenol at low temperature; then the hydrogenation reduction of p-benzoquinone to hydroquinone is catalyzed by Pt/C. At medium and high temperature, high selectivity can be achieved, and the conversion of p-benzoquinone can reach nearly completely.

Detailed ways

The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

A method for synthesizing hydroquinone by selective oxidation-reduction of phenol, comprising the steps:

S1: Add organic selenium catalyst containing carbon nanotubes, phenol and 30% hydrogen peroxide into the reaction flask, add N,N-dimethylformamide, stir evenly, fill with nitrogen, and react at 60°C for 1-2h after sealing;

S2: after the reaction is completed, the filtrate and the solid are collected by filtration, the filtrate is evaporated to remove N,N-dimethylformamide and then diluted with ethanol, followed by adding triisooctylamine to stir, the phenol has a weak acidity, and the triisooctylamine and phenol are used for A similar complexing force can be formed between them, destroying the combination between phenol and p-benzoquinone, reducing the solubility of benzoquinone in ethanol, so that the benzoquinone can be separated and p-benzoquinone can be collected;

S3: add a metal catalyst and pyridine into a round-bottomed flask, add the p-benzoquinone to the flask, add a hydrogen donor, and heat the mixture at 80-100° C. for 1-2 hours;

S4: After the reaction is completed, the reaction solution is concentrated, decoked and decolorized to obtain hydroquinone.

Further, the carbon nanotube-containing organoselenium catalyst is 0.5-5 wt % of the mass of phenol, and the molar ratio of the hydrogen peroxide to the phenol is 1-3:1.

Further, the preparation steps of the carbon nanotube-containing organoselenium catalyst are as follows:

1) Add 0.8g (0.01mol) selenium powder to distilled water, introduce nitrogen and stir evenly, then add 0.75g (0.02mol) aqueous solution of sodium borohydride, add 0.8g (0.01mol) selenium powder, heat up to 50 -60℃, reaction 40-60min;

2) adding saturated sodium carbonate solution dropwise to 10 ml aqueous solution of 0.02 mol of 4-bromo-2,6-difluorobenzoic acid, adjusting pH to 9-10;

3) The alkaline solution of step 2) was added dropwise to step 1), and the reaction was stirred at room temperature for 24h;

4) filter after the reaction, adjust the pH of the filtrate to 3-4 with dilute hydrochloric acid, filter with suction, wash and dry with water, and recrystallize with ethyl acetate to obtain diselenide carboxylate;

5) Put the modified carbon nanotubes in N,N-dimethylformamide (DMF) solvent, add the carboxylate diselenide, ultrasonically disperse for 30min, stir and reflux at 70-80°C for 12h, filter, After washing and drying, an organic selenium catalyst containing carbon nanotubes is obtained.

Wherein, the metal catalyst is selected from a platinum catalyst, a copper catalyst, a nickel catalyst or a palladium catalyst.

Wherein, the hydrogen donor is selected from one of cyclohexanone, isopropanol, isooctanol or cyclohexanol.

Wherein, the molar ratio of p-benzoquinone to hydrogen donor and pyridine is 1:5-10:1%-5%.

Example: prepared by the above steps, wherein,

The organic selenium catalyst containing carbon nanotubes can be prepared by the following steps: 1) adding 0.8g (0.01mol) selenium powder to distilled water, introducing nitrogen and stirring evenly, then adding 0.75g (0.02mol) sodium borohydride Add 0.8g (0.01mol) selenium powder, heat up to 50-60°C, and react for 40-60min; 2) Add saturated sodium carbonate solution dropwise to 0.02mol of 4-bromo-2,6-difluoro 10ml aqueous solution of benzoic acid, adjust the pH to 9-10; 3) Add the alkaline solution of step 2) dropwise to step 1), and stir at room temperature for 24 hours; 4) After the reaction is completed, filter the filtrate and adjust the filtrate with dilute hydrochloric acid pH to 3-4, suction filtered, washed with water and dried, recrystallized with ethyl acetate to obtain carboxylic acid diselenide; 5) Put the modified carbon nanotubes in N,N-dimethylformamide (DMF) solvent , adding the carboxylate diselenide, ultrasonically dispersing for 30 minutes, stirring and refluxing at 70-80° C. for 12 hours, filtering, washing, and drying to obtain an organic selenium catalyst containing carbon nanotubes.

The p-benzoquinone can be prepared by the following steps: add 0.47 mg of organic selenium catalyst containing carbon nanotubes, 0.47 g of phenol and 0.56 g of 30% hydrogen peroxide into the reaction flask, add 10 ml of DMF, stir evenly, fill with nitrogen, and seal at 60° C. The reaction was continued for 2h; after the reaction, the reaction solution was concentrated, decoked, and decolorized to obtain hydroquinone.

Example 1: 540mg platinum catalyst and 0.8mmol pyridine were added to a round-bottomed flask, 50mmol of the p-benzoquinone was added to the flask, 300mmol of cyclohexanone was added, and the mixture was heated at 80°C for 2 hours; after the reaction, the reaction solution was Concentration, decoking, decolorization and crystallization to obtain hydroquinone.

Example 2: Add 540 mg of copper catalyst and 1.2 mmol of pyridine into a round-bottomed flask, add 50 mmol of the p-benzoquinone to the flask, add 350 mmol of isopropanol, and heat the mixture at 80° C. for 2 hours; Concentration, decoking, decolorization and crystallization to obtain hydroquinone.

Example 3: 540mg nickel catalyst and 1.30mmol pyridine were added to a round-bottomed flask, 50mmol of the p-benzoquinone was added to the flask, 300mmol of isooctanol was added, and the mixture was heated at 80°C for 2 hours; Concentration, decoking, decolorization and crystallization to obtain hydroquinone.

Example 4: 540mg platinum catalyst and 1.65mmol pyridine were added to a round-bottomed flask, 50mmol of the p-benzoquinone was added to the flask, 450mmol of cyclohexanone was added, and the mixture was heated at 80°C for 2 hours; after the reaction, the reaction solution was Concentration, decoking, decolorization and crystallization to obtain hydroquinone.

Example 5: 540mg platinum catalyst and 3.0mmol pyridine were added to a round-bottomed flask, 50mmol of the p-benzoquinone was added to the flask, 500mmol of cyclohexanone was added, and the mixture was heated at 80°C for 2 hours; after the reaction, the reaction solution was Concentration, decoking, decolorization and crystallization to obtain hydroquinone.

It can be seen from the data in Table 1 that the conversion and selectivity of Comparative Examples 1-3 and Example 1 (using platinum catalyst and cyclohexanone as hydrogen donor) are better than those of Examples 2 and 3. On the basis, increasing the dosage of pyridine and cyclohexanone, the dosage of Example 4 can reach the best quality value of this case, and when the dosage is increased again, there is no obvious promoting effect on the conversion rate and selectivity.

Table 1

Although the embodiment of the present invention has been disclosed as above, it is not limited to the application listed in the description and the embodiment, and it can be applied to various fields suitable for the present invention. For those skilled in the art, it can be easily Therefore, the invention is not limited to the specific details without departing from the general concept defined by the appended claims and the scope of equivalents.

Claims (7)

1. a method for phenol selective redox synthesis of hydroquinone, is characterized in that, comprises the steps: S1: Add organic selenium catalyst containing carbon nanotubes, phenol and 30% hydrogen peroxide into the reaction flask, add N,N-dimethylformamide, stir evenly, fill with nitrogen, and react at 60 °C for 1-2 h after sealing; S2: after the reaction is completed, the filtrate and the solid are collected by filtration, the filtrate is evaporated to remove N,N-dimethylformamide and then diluted with ethanol, followed by adding triisooctylamine to stir, so that p-benzoquinone is precipitated from ethanol, and p-benzene is collected. Quinone; S3: add a metal catalyst and pyridine into a round-bottomed flask, add the p-benzoquinone to the flask, add a hydrogen donor, and heat the mixture at 80-100 °C for 1-2 hours; S4: after the reaction finishes, the reaction solution is concentrated, decoked, decolorized and crystallized to obtain hydroquinone; Wherein, the preparation steps of the carbon nanotube-containing organoselenium catalyst are as follows: 1) Add selenium powder to distilled water, stir evenly with nitrogen, then add an aqueous solution of sodium borohydride, add an equal amount of selenium powder, heat up to 50-60 °C, and react for 40-60 min; 2) Add the saturated sodium carbonate solution dropwise to the aqueous solution of 4-bromo-2,6-difluorobenzoic acid, and adjust the pH to 9-10; 3) The alkaline solution of step 2) was added dropwise to step 1), and the reaction was stirred at room temperature for 24 h; 4) After the reaction is completed, filter, adjust the pH of the filtrate to 3-4 with dilute hydrochloric acid, filter with suction, wash with water and dry, and recrystallize with ethyl acetate to obtain carboxylic acid diselenide; 5) Put the modified carbon nanotubes in a solvent, add the carboxylate diselenide, stir and reflux at 70-80 °C for 12-24 hours, filter, wash, and dry to obtain an organic selenium catalyst containing carbon nanotubes . 2. the method for phenol selective redox synthesis hydroquinone as claimed in claim 1, is characterized in that, the organic selenium catalyst of described carbon nanotube is 0.5-5wt% of phenol quality, and described hydrogen peroxide and phenol The molar ratio is 1-3:1. 3. the method for phenol selective redox synthesis hydroquinone as claimed in claim 1, is characterized in that, the mol ratio of described selenium powder and sodium borohydride, halogenated carboxylic acid is 1: 1: 1. 4. the method for phenol selective redox synthesis hydroquinone as claimed in claim 1, is characterized in that, described modified carbon nanotube is hydroxylated double-walled carbon nanotube, and described modified carbon nanotube and The mass ratio of the carboxylic acid diselenide is 1:5~10. 5. The method for synthesizing hydroquinone by selective redox of phenol as claimed in claim 1, wherein the metal catalyst is selected from a platinum catalyst, a copper catalyst, a nickel catalyst or a palladium catalyst. 6. the method for phenol selective redox synthesis hydroquinone as claimed in claim 1, is characterized in that, described hydrogen donor is selected from cyclohexanone, isopropanol, isooctanol or cyclohexanol A sort of. 7. the method for phenol selective redox synthesis hydroquinone as claimed in claim 1, is characterized in that, the mol ratio of p-benzoquinone and hydrogen donor, pyridine is 1:5～10:1%～5% .