WO2024000825A1

WO2024000825A1 - Method for selectively oxidizing styrene in water

Info

Publication number: WO2024000825A1
Application number: PCT/CN2022/118672
Authority: WO
Inventors: 陈新祥; 宋汪泽; 孔令蜜; 郑楠; 万洪刚; 白景佩; 王达伟; 苏振华
Original assignee: 江苏中利集团股份有限公司; 大连理工大学
Priority date: 2022-06-29
Filing date: 2022-09-14
Publication date: 2024-01-04
Also published as: CN114805246A; CN114805246B

Abstract

The present application relates to a method for selectively oxidizing styrene in water. The method comprises: adding styrene, a catalyst and an oxidizing agent to a reaction solvent, performing an oxidation reaction at 25-55°C, and filtering the resulting product after the oxidation reaction is completed, so as to obtain a filtrate, wherein the reaction solvent is water; the oxidizing agent is cumyl hydroperoxide or a hydrogen peroxide solution; and the catalyst is polymanganese porphyrin. The reaction solvent for the oxidization of styrene is water, which replaces a conventionally used organic solvent. The method is safe, inexpensive, non-toxic and pollution-free, and conforms to the modern concept of green chemistry; and the polymanganese porphyrin catalyst is used in combination with an oxidizing agent, such that a selective catalytic reaction is efficiently carried out in a water solvent. The system has short reaction time, a high conversion rate, and relatively high selectivity.

Description

A method for selective oxidation of styrene in water

This application claims the priority of the Chinese patent application with the filing date of June 29, 2022 and the application number 202210748420.2, the entire content of which is incorporated into this application by reference.

Technical field

The invention relates to the technical field of organic chemistry, and in particular to a method for selective oxidation of styrene in water.

Background technique

The styrene oxidation reaction is a classic organic reaction. The double bonds of styrene are highly reactive. Under the combined action of catalysts and oxidants, the double bonds of styrene are opened or broken to cause addition, oxidation and other reactions. , generating products such as styrene oxide, phenylacetaldehyde, benzaldehyde, and benzoic acid.

Styrene oxide can be used as a diluent, UV absorber, and flavoring agent for epoxy resin. It is also an important intermediate in organic synthesis, pharmaceuticals, and fragrance industries. For example, β-phenylethyl alcohol produced by hydrogenation of styrene oxide is rose oil, It is the main component of clove oil and neroli oil, and is widely used in the preparation of food, tobacco, soap and cosmetic flavors. In industry, styrene oxide is mainly synthesized by the halohydrin method, and a small amount is also synthesized by epoxidation of styrene with hydrogen peroxide. The halohydrin epoxidation method is simple, but has high material and energy consumption and serious pollution.

There are two main industrial production methods of benzaldehyde. One is to hydrolyze benzyl dichloride to prepare benzaldehyde, and the other is to oxidize toluene to prepare benzaldehyde. Among them, benzaldehyde prepared by hydrolysis of benzyl dichloride contains chlorine element, which affects the purity and application of the product. Although the entire process of toluene oxidation method does not contain chlorine element, in this reaction, due to the high temperature or pressure of the reaction, the product benzaldehyde is easily oxidized to benzoic acid, which not only reduces the yield of benzaldehyde but also increases the side effects. The cost of recovery and treatment of product benzoic acid.

Current research on styrene oxidation mainly focuses on designing new catalysts with higher catalytic performance. The product after the oxidation reaction of oxidant hydrogen peroxide is water, which is environmentally friendly and easy to post-process. It is in line with the development concept of green chemical industry. However, the oxidation ability of hydrogen peroxide and the selectivity of products are weak, so it requires high catalytic activity and good selectivity. Catalysts work synergistically with them to improve the yield and selectivity of reaction products. Therefore, it is necessary to develop a catalyst with high catalytic activity and good selectivity to catalyze the oxidation reaction of styrene to produce benzaldehyde.

Li Gang et al. (Journal of Dalian University of Technology 2022, 42(5): 535-538) disclosed a TS-1 synthesized from cheap raw materials as a catalyst for epoxidation; CN201210009309 disclosed a soluble zinc salt modified titanium molecular sieve Catalyst, and after 2 hours of reaction, the styrene conversion rate reaches 86%, and the styrene oxidation selectivity reaches 64%; CN101346362B discloses a metal ion exchange zeolite, the reaction is 4 hours, the styrene conversion rate is 99.9%, and the styrene oxide selectivity is 99.9%. The property is 82.6%; Li Chengyong et al. (Journal of Central South University (Natural Science Edition), 2013, 44(8): 3142-3145) disclosed a mesoporous alumina-supported copper oxide catalyst that reacted for 6 hours at 80°C. The ethylene conversion rate was 87.94% and the styrene oxide selectivity was 91.1%.

Normally, most of these catalytic reactions are carried out in organic solvents. Organic solvents are relatively expensive, most of them are toxic and environmentally polluting, and pose certain safety risks.

Contents of the invention

The purpose of the present invention is to provide a method for selective oxidation of styrene in water, which is safe, cheap, non-toxic, non-polluting, and in line with the concept of modern green chemistry.

In order to achieve the above object, the present invention provides the following technical solution: a method for selective oxidation of styrene in water, the method includes:

Add styrene, catalyst and oxidant to the reaction solvent, and perform an oxidation reaction at 25-55°C. After the oxidation reaction is completed, the obtained product is filtered to obtain a filtrate;

Wherein, the reaction solvent is water;

The oxidant is cumene hydroperoxide or hydrogen peroxide solution;

The catalyst is polymanganese porphyrin.

Further, the molar ratio of styrene, catalyst and oxidant is 1:0.05: (2-4).

Further, the duration of the oxidation reaction is 1-2 h.

Further, the mass concentration of the hydrogen peroxide solution is 20%-30%.

Further, the preparation method of the polymanganese porphyrin is:

S1. Dissolve pyrrole and 4-bromobenzaldehyde in a mixed solution of propionic acid and acetic acid, stir and react at a temperature of 100-140°C for 1-6 hours, then cool to room temperature, and rotary evaporate under reduced pressure to remove part of the propionic acid. The mixed solution with acetic acid is washed with methanol and dried to obtain 5,10,15,20-tetrakis(4-bromophenyl)porphyrin;

S2. Dissolve manganese acetate and the 5,10,15,20-tetrakis(4-bromophenyl)porphyrin in N,N-dimethylformamide and react with stirring at a temperature of 100-130°C. 3-5h, remove N,N-dimethylformamide by rotary evaporation under reduced pressure, centrifuge and wash with water, collect the precipitate, and dry the precipitate to constant weight to obtain manganese porphyrin;

S3. Dissolve the manganese porphyrin and bis(triphenylphosphine)palladium dichloride in dimethyl sulfoxide, add 1,4-diethynylbenzene into the reaction system, and then add triethylamine slowly Add dropwise to the reaction system, evacuate the reaction system, fill it with protective gas, react at 100-130°C for 10-30 minutes, centrifuge and wash the obtained product with dichloromethane, collect the precipitate, and dry the precipitate To constant weight, polymanganese porphyrin is obtained.

Further, in the S1, the molar ratio of the pyrrole and 4-bromobenzaldehyde is 1: (0.8-1.2); the mixing ratio of the propionic acid and acetic acid is 3:1.

Further, in the S2, the molar ratio of the manganese acetate and 5,10,15,20-tetrakis(4-bromophenyl)porphyrin is (3-5):1.

Further, in the S3, the molar ratio of the manganese porphyrin, bis(triphenylphosphine)palladium dichloride, 1,4-diethynylbenzene and triethylamine is 1: (1-2) :2: (0.03-0.05).

Furthermore, when the catalyst is cumene hydroperoxide, the conversion rate of styrene is 96%, and the selectivity of styrene oxide is 93%.

Furthermore, when the catalyst is a hydrogen peroxide solution, the conversion rate of styrene is 99%, and the benzaldehyde selectivity is 99%.

The beneficial effects of the present invention are: the reaction solvent of styrene oxidation is water, which replaces the traditionally used organic solvent. The method is safe, cheap, non-toxic, non-polluting, in line with the concept of modern green chemistry, and uses a polymanganese porphyrin catalyst. , combined with an oxidant, can efficiently carry out selective catalytic reactions in water solvents. This system has short reaction time, high conversion rate and high selectivity.

The above description is only an overview of the technical solutions of the present invention. In order to have a clearer understanding of the technical means of the present invention and implement them according to the contents of the description, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings.

Description of drawings

Figure 1 is the NMR pattern of 5,10,15,20-tetrakis(4-bromophenyl)porphyrin (TBrPP) prepared in Example 1 of the present invention.

Figure 2 is an infrared image of the manganese porphyrin prepared in Example 1 of the present invention.

Figure 3 is an infrared image of the polymanganese porphyrin prepared in Example 1 of the present invention.

Detailed ways

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

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

The method for selective oxidation of styrene in water shown in this application includes: adding styrene, a catalyst and an oxidizing agent into a reaction solvent, and performing an oxidation reaction at 25-55°C. After the oxidation reaction is completed, the obtained product Perform filtration to obtain filtrate.

The reaction solvent is water, which can be deionized water or tap water, and is not specifically limited here. Water replaces the traditionally used organic solvents. This method is safe, cheap, non-toxic, non-polluting and in line with the concept of modern green chemistry.

The oxidizing agent is cumene hydroperoxide or hydrogen peroxide solution. The catalyst is polymanganese porphyrin. The polymanganese porphyrin is combined with an oxidant to efficiently perform a selective catalytic reaction on styrene in a water solvent. This system has a short reaction time, high conversion rate and high selectivity.

When the catalyst is cumene hydroperoxide, the styrene conversion rate is 96% and the styrene oxidation selectivity is 93%. When the catalyst is a hydrogen peroxide solution, the conversion rate of styrene is 99% and the selectivity of benzaldehyde is 99%.

In the oxidation reaction, the molar ratio of styrene, catalyst and oxidant is 1:0.05: (2-4), and the oxidation reaction time is 1-2h. The specific temperature of the oxidation reaction can be selected from 25-55°C according to actual needs. There is no specific limitation on the heating of the reaction system, and heating methods such as heating plates and oil baths can be used. There are no specific restrictions on the utensils used to hold the reaction system, and they can be selected according to implementation needs, such as round-bottomed flasks.

In addition, during the oxidation reaction, the reactants need to be stirred, and magnetic stirring can be used. There is no specific limit on the stirring speed, as long as the reactants are mixed.

The mass concentration of hydrogen peroxide solution is 20%-30%. In this embodiment, the mass concentration of the hydrogen peroxide solution is 30%, but it is not limited thereto. Hydrogen peroxide solutions with mass concentrations of 21%, 22%, 23%, 24%, 25%, etc. may also be used.

In this embodiment, the preparation method of polymanganese porphyrin is:

S1. Dissolve pyrrole and 4-bromobenzaldehyde in a mixed solution of propionic acid and acetic acid, stir and react at a temperature of 100-140°C for 1-6 hours, then cool to room temperature, and rotary evaporate under reduced pressure to remove part of the propionic acid and acetic acid. The mixed solution was washed with methanol and dried to obtain 5,10,15,20-tetrakis(4-bromophenyl)porphyrin;

S2. Dissolve manganese acetate and 5,10,15,20-tetrakis(4-bromophenyl)porphyrin in N,N-dimethylformamide and react with stirring at a temperature of 100-130°C 3- 5h, remove N,N-dimethylformamide by rotary evaporation under reduced pressure, centrifuge and wash with water, collect the precipitate, and dry the precipitate to constant weight to obtain manganese porphyrin;

S3. Dissolve manganese porphyrin and bis(triphenylphosphine)palladium dichloride in dimethyl sulfoxide, add 1,4-diethynylbenzene into the reaction system, and then slowly add triethylamine dropwise Into the reaction system, evacuate the reaction system, fill it with protective gas, and react at 100-130°C for 10-30 minutes. The obtained product is centrifuged and washed with dichloromethane, and the precipitate is collected and dried to constant weight. Polymanganese porphyrin was obtained.

Among them, in S1, the molar ratio of pyrrole and 4-bromobenzaldehyde is 1: (0.8-1.2); the mixing ratio of propionic acid and acetic acid is 3:1.

In S2, the molar ratio of manganese acetate and 5,10,15,20-tetrakis(4-bromophenyl)porphyrin is (3-5):1.

In S3, the molar ratio of manganese porphyrin, bis(triphenylphosphine)palladium dichloride, 1,4-diethynylbenzene and triethylamine is 1: (1-2): 2: (0.03-0.05 ).

Among them, in S3, in order to seal the reaction system, a rubber stopper can be used for sealing. The protective gas is gas such as nitrogen or argon, which is not specifically limited here. When washing the product obtained in each step, the corresponding solvent is generally used for washing three times, but it can also be washed twice, four times, etc. To dry the product, a vacuum drying oven can be used to avoid components in the air from affecting the product during heating.

The method of removing solvent by vacuum rotary evaporation is an existing technology and will not be described in detail here.

The above-mentioned powder samples can be weighed using an electronic balance, and the liquid samples can be weighed using a pipette, graduated cylinder, etc. For example, the above-mentioned 1,4-diethynylbenzene can be accurately transferred using a pipette.

Regarding the method for selective oxidation of styrene in water, the details are as follows:

The synthesis steps of polymanganese porphyrin include:

Accurately weigh 1 molar equivalent of pyrrole and 0.8-1.2 molar equivalent of 4-bromobenzaldehyde, dissolve in a mixed solution of propionic acid and acetic acid (3:1), stir and react at a temperature of 100-140°C for 1-6 hours and then cool. to room temperature, evaporate under reduced pressure to remove most of the propionic acid and acetic acid, wash three times with methanol, and dry to obtain 5,10,15,20-tetrakis(4-bromophenyl)porphyrin.

Accurately weigh 3-5 molar equivalents of manganese acetate and 1 molar equivalent of 5,10,15,20-tetrakis(4-bromophenyl)porphyrin, dissolve in dimethylformamide (DMF) and incubate at 100-130℃ The reaction was carried out for 3-5 hours under stirring at high temperature, and then the solvent N,N-dimethylformamide was removed by rotary evaporation under reduced pressure, and centrifuged and washed three times with deionized water to collect the precipitate. The precipitate was placed in a vacuum drying oven and dried to constant weight. Obtain manganese porphyrin.

Accurately weigh 1 molar equivalent of manganese porphyrin and 1-2 molar equivalents of bis(triphenylphosphine)palladium dichloride and dissolve them in dimethyl sulfoxide (DMSO). Use a pipette to take 2 molar equivalents of 1,4 -Add diethynylbenzene into the reaction system, then slowly add 0.03-0.05 molar equivalent of triethylamine into the system dropwise, cover with a rubber stopper, evacuate, fill with N ₂ , and react at 100-130°C for 10-30 minutes. The obtained reaction product is washed and centrifuged three times with dichloromethane (DCM), the precipitate is collected, and the precipitate is placed in a vacuum drying oven and dried to constant weight to obtain polymanganese porphyrin.

The specific oxidation reaction is: accurately weigh 1 molar equivalent of styrene and add it to water, add 0.05 molar equivalent of polymanganese porphyrin and 2-4 molar equivalents of cumene hydroperoxide, control the temperature at 25-55°C, and react 1- 2h, filter the product and collect the filtrate. In this reaction, styrene is selectively oxidized to product A, styrene oxide

The conversion rate of styrene and the selectivity of product A for oxidation of styrene were determined by high performance liquid chromatography (HPLC).

Another oxidation reaction is as follows: accurately weigh 1 molar equivalent of styrene and add it to water, add 0.05 molar equivalent of polymanganese porphyrin and 2-4 molar equivalents of hydrogen peroxide, control the temperature at 25-55°C, and react for 1-2 hours , filter the product and collect the filtrate. In this reaction, styrene is selectively oxidized to product B benzaldehyde

The conversion rate of styrene and the selectivity of product B benzaldehyde were determined by high performance liquid chromatography (HPLC).

The preparation method is further described below with reference to specific examples.

Example 1

Use a pipette to absorb pyrrole (2mL, 1equiv, 30mmol), use an electronic balance to weigh 4-bromobenzaldehyde (5g, 1equiv, 30mmol), and add it to a 250mL round-bottomed flask. Weigh 45mL propionic acid and 15mL acetic acid in a graduated cylinder respectively. In a round-bottom flask, add a magnet, use an oil bath to heat, stir the reaction at 120°C for 2 hours, then cool to room temperature, rotary evaporate under reduced pressure to remove most of the propionic acid and acetic acid, wash three times with methanol, and dry to obtain 5,10 ,15,20-tetrakis(4-bromophenyl)porphyrin. Please refer to Figure 1 to demonstrate the NMR pattern of 5,10,15,20-tetrakis(4-bromophenyl)porphyrin obtained in this example.

Use an electronic balance to weigh manganese acetate (268 mg, 1 equiv, 1 mmol) and 5,10,15,20-tetrakis(4-bromophenyl)porphyrin (200 mg, 0.33 equiv, 0.33 mmol) respectively, and add them to a 25 mL reaction bottle and graduated cylinder. Weigh 6mL of DMF into the reaction flask, add a magnet, and react for 3 hours with stirring at a temperature of 110°C. Then remove the solvent DMF by rotary evaporation under reduced pressure, use deionized water and centrifuge at 8800r/min for 5min, and repeat washing three times. , put the obtained precipitate into an oven and dry it to obtain manganese porphyrin. Please refer to Figure 2 to demonstrate the infrared pattern of the manganese porphyrin obtained in this example.

Use an electronic balance to weigh manganese porphyrin (200mg, 1equiv, 0.2mmol) and bis(triphenylphosphine)palladium dichloride (112.6mg, 1.25equiv, 0.16mmol) respectively, add them to a 25mL reaction bottle, and use a pipette to take 1 , 4-Diethynylbenzene (50.0 mg, 2 equiv, 0.4 mmol) was added to the reaction bottle, then triethylamine (894 μL, 0.03 equiv, 0.006 mmol) was slowly added dropwise to DMSO, a magnet was added, and the rubber stopper was capped. Evacuate, fill with N ₂ , place in a 100°C reaction platform, stir, and react for 30 minutes. Use DCM to centrifuge at 8800 r/min for 5 minutes. Repeat washing three times. Place the precipitate in an oven to dry to obtain polymanganese porphyrin. Please refer to Figure 3 to demonstrate the infrared pattern of the polymanganese porphyrin obtained in this example.

Example 2

Add styrene (11.5 μL, 0.1 equiv, 0.1 mmol) to 1 mL of water, add polymanganoporphyrin (5.0 mg, 0.005 equiv, 0.0005 mmol), and then add cumene hydroperoxide (43.4 μL, 0.3 equiv, 0.3 mmol) ), react with magnetic stirring at 25°C for 1 hour, and obtain the product styrene oxide.

Among them, the styrene conversion rate is 42% and the styrene oxidation selectivity is 84%.

Example 3

Add styrene (11.5 μL, 0.1 equiv, 0.1 mmol) to 1 mL of water, add polymanganoporphyrin (5.0 mg, 0.005 equiv, 0.0005 mmol), and then add cumene hydroperoxide (43.4 μL, 0.3 equiv, 0.3 mmol) ), react with magnetic stirring at 40°C for 1 hour, and obtain the product styrene oxide.

Among them, the styrene conversion rate is 74% and the styrene oxidation selectivity is 80%.

Example 4

Add styrene (11.5 μL, 0.1 equiv, 0.1 mmol) to 1 mL of water, add polymanganoporphyrin (5.0 mg, 0.005 equiv, 0.0005 mmol), and then add cumene hydroperoxide (43.4 μL, 0.3 equiv, 0.3 mmol) ), react with magnetic stirring at 55°C for 1 hour, and obtain the product styrene oxide.

Among them, the styrene conversion rate is 96% and the styrene oxidation selectivity is 93%.

Example 5

Add styrene (11.5 μL, 0.1 equiv, 0.1 mmol) to 1 mL of water, add polymanganoporphyrin (5.0 mg, 0.005 equiv, 0.0005 mmol), then add hydrogen peroxide solution (30.6 μL, 0.3 equiv, 0.3 mmol), The reaction was carried out with magnetic stirring at 55°C for 1 hour to obtain the product benzaldehyde.

Among them, the styrene conversion rate is 99% and the benzaldehyde selectivity is 99%.

In summary, the reaction solvent for styrene oxidation is water, which replaces the traditionally used organic solvents. This method is safe, cheap, non-toxic, and non-polluting. It is in line with the concept of modern green chemistry and uses polymanganese porphyrin catalysts and oxidants. The selective catalytic reaction is efficiently carried out in aqueous solvent. The system has short reaction time, high conversion rate and high selectivity.

The technical features of the above embodiments can be combined in any way. To simplify the description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, all possible combinations should be used. It is considered to be within the scope of this manual.

The above embodiments only express several embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention. It should be noted that, for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the scope of protection of the patent of the present invention should be determined by the appended claims.

Claims

A method for selective oxidation of styrene in water, characterized in that the method includes:

Add styrene, catalyst and oxidant to the reaction solvent, and perform an oxidation reaction at 25-55°C. After the oxidation reaction is completed, the obtained product is filtered to obtain a filtrate;

Wherein, the reaction solvent is water;

The oxidant is cumene hydroperoxide or hydrogen peroxide solution;

The catalyst is polymanganese porphyrin.
The method for selective oxidation of styrene in water according to claim 1, wherein the molar ratio of styrene, catalyst and oxidant is 1:0.05: (2-4).
The method for selective oxidation of styrene in water according to claim 1, wherein the duration of the oxidation reaction is 1-2 h.
The method for selective oxidation of styrene in water according to claim 1, wherein the mass concentration of the hydrogen peroxide solution is 20%-30%.
The method for selective oxidation of styrene in water according to claim 1, wherein the preparation method of the polymanganese porphyrin is:

S1. Dissolve pyrrole and 4-bromobenzaldehyde in a mixed solution of propionic acid and acetic acid, stir and react at a temperature of 100-140°C for 1-6 hours, then cool to room temperature, and rotary evaporate under reduced pressure to remove part of the propionic acid. The mixed solution with acetic acid is washed with methanol and dried to obtain 5,10,15,20-tetrakis(4-bromophenyl)porphyrin;

S2. Dissolve manganese acetate and the 5,10,15,20-tetrakis(4-bromophenyl)porphyrin in N,N-dimethylformamide and react with stirring at a temperature of 100-130°C. 3-5h, remove N,N-dimethylformamide by rotary evaporation under reduced pressure, centrifuge and wash with water, collect the precipitate, and dry the precipitate to constant weight to obtain manganese porphyrin;

S3. Dissolve the manganese porphyrin and bis(triphenylphosphine)palladium dichloride in dimethyl sulfoxide, add 1,4-diethynylbenzene into the reaction system, and then add triethylamine slowly Add dropwise to the reaction system, evacuate the reaction system, fill it with protective gas, react at 100-130°C for 10-30 minutes, centrifuge and wash the obtained product with dichloromethane, collect the precipitate, and dry the precipitate To constant weight, polymanganese porphyrin is obtained.
The method for selective oxidation of styrene in water according to claim 5, wherein in the S1, the molar ratio of the pyrrole and 4-bromobenzaldehyde is 1: (0.8-1.2); The mixing ratio of acid and acetic acid is 3:1.
The method for selective oxidation of styrene in water according to claim 5, wherein in the S2, the ratio of the manganese acetate and 5,10,15,20-tetrakis (4-bromophenyl) porphyrin The molar ratio is (3-5):1.
The method for selective oxidation of styrene in water according to claim 5, wherein in the S3, the manganese porphyrin, bis(triphenylphosphine)palladium dichloride, 1,4-diethyne The molar ratio of benzene and triethylamine is 1: (1-2): 2: (0.03-0.05).
The method for selective oxidation of styrene in water according to claim 1, wherein when the catalyst is cumene hydroperoxide, the conversion rate of styrene is 96%, and the styrene oxidation selectivity is 93%.
The method for selective oxidation of styrene in water according to claim 1, wherein when the catalyst is a hydrogen peroxide solution, the conversion rate of styrene is 99% and the benzaldehyde selectivity is 99%.