CN114682299B

CN114682299B - Polymer nanoparticle loaded acid-base synergistic catalyst and preparation method and application thereof

Info

Publication number: CN114682299B
Application number: CN202210357541.4A
Authority: CN
Inventors: 陈天有; 肖伟; 丘美爽; 易昌凤; 徐祖顺
Original assignee: Hubei University
Current assignee: Hubei University
Priority date: 2022-04-02
Filing date: 2022-04-02
Publication date: 2023-06-20
Anticipated expiration: 2042-04-02
Also published as: CN114682299A

Abstract

The embodiment of the application provides a polymer nanoparticle supported acid-base synergistic catalyst, and a preparation method and application thereof, and relates to the fields of chemical industry and organic synthesis. The polymer nanoparticle supported acid-base synergistic catalyst is mainly prepared from raw materials comprising a phenolic hydroxyl group-containing copolymer and a primary amine-containing copolymer by a nano precipitation method. The preparation method of the polymer nanoparticle supported acid-base synergistic catalyst is simple, convenient and controllable, and is easy for large-scale production; the prepared polymer nanoparticle supported acid-base synergistic catalyst has mild catalytic conditions, uses water as a solvent, is easy to recover and reuse, has high catalytic activity on aldol condensation reaction, and is beneficial to improving the production efficiency and economic benefit of aldol condensation reaction.

Description

Polymer nanoparticle loaded acid-base synergistic catalyst and preparation method and application thereof

Technical Field

The application relates to the field of chemical and organic synthesis, in particular to a polymer nanoparticle supported acid-base synergistic catalyst, and a preparation method and application thereof.

Background

Aldol condensation reaction (also called aldol condensation) is one of the basic reactions of organic synthesis, and new carbon-carbon bonds can be formed in molecules through aldol condensation reaction, so as to achieve the effect of carbon chain growth. Aldol condensation reactions include intermolecular aldol condensation and intramolecular aldol condensation, wherein the products of intermolecular aldol condensation are usually beta-hydroxy compounds and alpha, beta-unsaturated aldehydes or ketones, which are one of the important raw materials commonly used in the fields of organic synthesis, high molecular and fine chemical engineering. Along with the increasing demands of people on environmental protection, the use of clean, cheap and sustainable raw materials for aldol condensation reaction is a future trend, for example, water is selected as a reaction solvent for aldol condensation reaction at normal temperature and normal pressure. However, aldol condensation reactions are typically carried out under acidic or basic conditions, and thus require the use of a catalyst.

It is found that the homogeneous acid catalyst and/or the homogeneous alkaline catalyst has mild reaction condition and relatively high reaction activity. Further research shows that the acid component and the alkaline component in the catalyst have synergistic effect under certain conditions, so that the aldol condensation rate and conversion rate can be greatly improved. However, neutralization and deactivation of acid-base sites in a homogeneous acid-base synergistic catalytic process remains a challenging problem. The multi-component supported catalytic system provides possibility for realizing synergistic catalysis of aldol condensation in aqueous solution, wherein phenolic hydroxyl and primary amine catalytic system can efficiently catalyze aldol condensation to obtain corresponding beta-hydroxyaldehyde or ketone and alpha, beta-unsaturated aldehyde or ketone. The reaction may be carried out at normal temperature and pressure. In order to prevent neutralization of acid-base sites and deactivation of the catalyst, separation of products and reuse of the catalyst are facilitated, and the components of the phenolic hydroxyl and primary amine catalysts may be immobilized on a support.

The current research on supported catalysts that catalyze aldol reactions has focused mainly on mesoporous silica materials. The mesoporous silica supported acid-base synergistic catalyst mainly adopts grafting and co-condensation methods to fix the catalytic group on the mesoporous silica. The method can not only better avoid the neutralization of acid-base sites, but also obtain the catalyst with good appearance, easy surface modification and good catalytic performance. However, the grafting and co-condensation method used for preparing the mesoporous silica supported acid-base synergistic catalyst has the defects of high operation difficulty, complicated synthesis steps and difficulty in controlling the distribution and proportion of acid-base components.

As an alternative loading method, the copolymer loaded catalyst has the advantages of simple synthesis, easy regulation of component proportion, strong hydrophobicity and the like. Therefore, the polymer nanoparticle supported acid-base synergistic catalyst which is simpler to prepare and more flexible to regulate and control is developed, the production efficiency and the economic benefit of aldol condensation reaction are greatly improved, and a new direction is explored for the research of the supported catalyst.

Disclosure of Invention

The embodiment of the application aims to provide a polymer nanoparticle supported acid-base synergistic catalyst, a preparation method and application thereof, wherein the preparation method of the polymer nanoparticle supported acid-base synergistic catalyst is simple and controllable, is easy for large-scale production, and can control the distribution and proportion of acid-base components in the catalyst; the polymer nanoparticle supported acid-base synergistic catalyst has high catalytic activity on aldol condensation reaction.

In a first aspect, an embodiment of the present application provides a method for preparing a polymer nanoparticle supported acid-base synergistic catalyst, where a raw material including a phenolic hydroxyl group-containing copolymer and a primary amine-containing copolymer is selected and prepared by a nano precipitation method; wherein the molecular structural formula of the copolymer containing phenolic hydroxyl groups and the copolymer containing primary amine is respectively

n and l are positive integers, x and y are 10% -50%, and the weight average molecular weight of the copolymer containing phenolic hydroxyl and the copolymer containing primary amine is 5×10 ³ ～100×10 ³ 。

In the technical scheme, the activity of the polymer nanoparticle supported acid-base synergistic catalyst mainly depends on the synergistic effect between active groups of phenolic hydroxyl groups and primary amine groups, so that a composite catalytic system is formed by using a copolymer containing phenolic hydroxyl groups and primary amine groups; in addition, the copolymer containing the phenolic hydroxyl and the primary amine is favorable for improving the synergistic effect between active groups of the phenolic hydroxyl and the primary amine, so that the high catalytic activity of aldol condensation reaction and the high recycling efficiency are realized. The preparation method is simple, convenient and controllable, is easy to produce the polymer nano-particle supported acid-base synergistic catalyst on a large scale, and can control the distribution and the proportion of acid-base components in the catalyst.

In one possible implementation, the ratio of the phenolic hydroxyl-containing copolymer to the primary amine-containing copolymer in the raw materials is (25% -78%) to (22% -75%) in mass percent.

In the above technical solution, the inventors found in the process of implementing the present application that: if the ratio of the above two copolymers is not within the range defined in the present application, the catalyst formed has poor catalytic activity for aldol condensation reaction and hardly catalyzes the reaction. The phenol-containing hydroxyl copolymer and the primary amine-containing copolymer with the specific proportions have good synergistic catalytic effect and high catalytic activity.

In one possible implementation, the nano-precipitation method specifically includes the following steps:

dissolving a phenolic hydroxyl-containing copolymer and a primary amine-containing copolymer in an organic solvent to form a mixed solution;

and adding the mixed solution into the mixed deionized water solution containing the OP-10 emulsifier under the stirring condition, and reacting to obtain the polymer nano-particle supported acid-base synergistic catalyst.

In the technical scheme, two copolymers are simultaneously dissolved in an organic solvent, then the organic solvent is rapidly added into a mixed deionized water solution, and the OP-10 emulsifier in the mixed deionized water solution has the function of enabling the copolymers to form stable copolymer emulsion in the mixed water solution so as to prevent the copolymers from being aggregated in large blocks, and after the copolymers originally dissolved in the organic solvent are added into water, the copolymers precipitate out to form copolymer nano-sized particles with similar sizes. Furthermore, the inventors found in the course of implementing the present application that: the OP-10 emulsifier has good emulsification effect, is cheap and easy to obtain, and the formed copolymer emulsion is very stable and is not easy to aggregate; on the other hand, if an ionic surfactant (such as sodium dodecyl benzene sulfonate and cetyltrimethylammonium bromide) is used, the copolymer is aggregated in large blocks, and a copolymer emulsion cannot be formed, so that the catalytic effect is poor.

In one possible implementation, the total mass of the phenolic hydroxyl-containing copolymer and the primary amine-containing copolymer is 0.25% to 1.40% of the mass of the organic solvent;

and/or the organic solvent is at least one of N, N-dimethylformamide and tetrahydrofuran;

and/or the mass of the OP-10 emulsifier is 0.1 to 1.0 percent of the mass of the mixed deionized water solution.

In the technical scheme, the total mass of the two copolymers is 0.25-1.40% of the mass of the organic solvent, so that the copolymers can be completely dissolved and quickly precipitated after encountering deionized water. At least one of N, N-dimethylformamide and tetrahydrofuran is selected as an organic solvent, and both copolymers can be dissolved at the same time. The dosage of the OP-10 emulsifier is 0.1 to 1.0 percent of the mass of the mixed deionized water solution, and the OP-10 emulsifier has good stabilizing effect on the copolymer.

In one possible implementation, the stirring speed is 400-1800 rpm;

and/or, the reaction temperature is 30-60 ℃;

and/or the reaction time is 2-12 hours.

In the technical scheme, the rotation speed of stirring is controlled to be 400-1800 revolutions per minute, so that the polymer can be uniformly precipitated; the reaction temperature is controlled to be 30-60 ℃, the reaction time is 2-12 hours, and the smooth and thorough precipitation of the copolymer is ensured.

In one possible implementation, the mixed solution is added to the mixed deionized water solution for a period of no more than 3 seconds, wherein the mass ratio of the mixed solution to the mixed deionized water solution is (10.03-20.18) to 100.

In the technical scheme, the mixed solution is quickly added into the mixed deionized water solution, so that copolymer nano particles with uniform size and stable dispersion can be formed.

In a second aspect, an embodiment of the present application provides a polymer nanoparticle supported acid-base synergistic catalyst, which is prepared by using the preparation method of the polymer nanoparticle supported acid-base synergistic catalyst provided in the first aspect.

In the technical scheme, the polymer nanoparticle supported acid-base synergistic catalyst has high catalytic activity on aldol condensation reaction, and is beneficial to improving the production efficiency and economic benefit of aldol condensation reaction.

In a third aspect, an embodiment of the present application provides an application of the polymer nanoparticle-supported acid-base synergistic catalyst provided in the second aspect, where the polymer nanoparticle-supported acid-base synergistic catalyst is used for catalyzing aldol condensation reaction.

In the technical scheme, the polymer nanoparticle supported acid-base synergistic catalyst is used for aldol condensation reaction, and has wide selection range of substrate aldehyde and ketone and good catalytic effect.

In one possible implementation, the polymer nanoparticle-supported acid-base co-catalyst is used to catalyze an aldol condensation reaction of 4-nitrobenzaldehyde with acetone, which includes the steps of:

preparing an acetone solution of 4-nitrobenzaldehyde, wherein the molar ratio of the 4-nitrobenzaldehyde to the acetone is 1:15-25;

mixing polymer nano-particles loaded acid-base synergistic catalyst and acetone solution of 4-nitrobenzaldehyde according to the mass ratio of (2.3-9.2) to 100, and carrying out reflux reaction in nitrogen for 5-24 hours at the temperature of 30-60 ℃.

In the technical scheme, the polymer nanoparticle supported acid-base synergistic catalyst has high catalytic activity for catalyzing the condensation of acetone and 4-nitrobenzaldehyde aldol, the corresponding catalytic condition is mild and simple, water is used as a solvent, an organic solvent is not required, and the catalyst is easy to recycle and reuse.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments of the present application will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a nuclear magnetic resonance hydrogen spectrum of a phenolic hydroxyl group-containing copolymer in example 1 of the present application;

FIG. 2 is a nuclear magnetic resonance hydrogen spectrum of a primary amine-containing copolymer in example 1 of the present application;

FIG. 3 is a graph showing the particle size distribution of the polymer nanoparticle supported acid-base synergistic catalyst in example 1 of the present application;

fig. 4 is a fourier transform infrared spectrum of a polymer nanoparticle-supported acid-base synergy catalyst in example 1 of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.

The polymer nanoparticle supported acid-base synergistic catalyst of the embodiment of the application and the preparation method and application thereof are specifically described below.

The embodiment of the application provides a preparation method of a polymer nanoparticle supported acid-base synergistic catalyst, which is prepared by adopting raw materials comprising a phenolic hydroxyl group-containing copolymer and a primary amine-containing copolymer through a nano precipitation method; wherein the molecular structural formula of the copolymer containing phenolic hydroxyl groups and the copolymer containing primary amine is respectively

n and l are positive integers, and x and y are 10% -50%, for example, x and y are respectively 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% or 50% or intermediate values between any two values; the weight average molecular weight of the phenolic hydroxyl group-containing copolymer and the primary amine-containing copolymer is 5 multiplied by 10 ³ ～100×10 ³ For example, the weight average molecular weight of the phenolic hydroxyl group-containing copolymer is 5000, 10000, 20000, 30000, 40000, 50000, 60000, 70000, 80000, 90000 or 100000, or an intermediate value between any two of the above values; the weight average molecular weight of the primary amine-containing copolymer is 5000, 10000, 20000, 30000, 40000, 50000, 60000, 70000, 80000, 90000, or 100000, or an intermediate value between any two of the foregoing. The values of x and y in the two copolymers, namely the phenolic hydroxyl group-containing copolymer and the primary amine-containing copolymer, can be the same or different; weight average molecular weight of the two copolymersThe amounts may be the same or different, and the present application is not limited thereto.

As one possible embodiment, the phenolic hydroxyl group-containing copolymer may be prepared according to the following preparation process:

①

the preparation of compound 1 can be referred to as follows: dissolving caffeic acid in N, N-dimethylformamide, adding triethylamine, stirring, heating to 80-120 ℃ under the protection of nitrogen, and reacting for 0.5-2 hours.

After the reaction is finished, the mixture obtained by the reaction is cooled to room temperature, rotary evaporation is carried out to 85-95 ℃, and unreacted triethylamine and N, N-dimethylformamide are removed, so that a reaction mixture is obtained.

The reaction mixture was separated by silica chromatography to give compound 1 as a pale yellow oil.

②

The preparation of compound 2 can be referred to as follows: 2-carbonic acid-2-tertiary butyl ester is dissolved in tetrahydrofuran, then 4-dimethylaminopyridine is added as a catalyst, and finally compound 1 is added for reaction for 8-16 hours under the condition of low temperature.

After the reaction, washing the reaction mixture by using an ammonium chloride solution with the mass fraction of 4% -8%, removing excessive 2-carbonic acid-2-tert-butyl ester, extracting the product by using ethyl acetate, repeating the washing and extracting processes for three times, removing the ethyl acetate by rotary evaporation, and finally separating by using a silica chromatographic column to obtain the compound 2 as pale yellow oily liquid.

③

The preparation method of the copolymer containing the tert-butyloxycarbonyl group specifically comprises the following steps: dissolving styrene and a compound 2 in 1, 4-dioxane, adding azodiisobutyronitrile under the protection of nitrogen, and then heating to 60-80 ℃ and stirring for 20-30 hours, wherein the molar ratio of the styrene to the compound 2 is (1-9) to 1; the mass of the azodiisobutyronitrile is 1.0-3.0% of the total mass of the styrene and the compound 2; the mass of the 1, 4-dioxane is 10 to 30 times of the total mass of the styrene and the compound 2.

After cooling to room temperature, the solution is dripped into the stirred methanol solution to obtain white solid, and the tert-butoxycarbonyl copolymer is obtained after filtration and drying, and the yield is generally 40% -60%.

④

The preparation method of the phenolic hydroxyl group-containing copolymer specifically comprises the following steps: dissolving the obtained copolymer containing the tert-butyloxycarbonyl group into dichloromethane, adding trifluoroacetic acid under stirring, and reacting for 10-15 hours at room temperature, wherein the molar ratio of the trifluoroacetic acid to the copolymer containing the tert-butyloxycarbonyl group is (10-15) to 1; the mass of the methylene dichloride is 10 to 20 times of that of the copolymer containing the tert-butyloxycarbonyl group.

The reaction mixture is dried by spin, then dissolved by a proper amount of tetrahydrofuran, the mass of the tetrahydrofuran is 10-20 times of the mass of the copolymer containing tert-butyloxycarbonyl group, the obtained solution is dripped into petroleum ether which is stirred to obtain brown solid, the precipitate is collected by filtration and dried, and the copolymer containing phenolic hydroxyl group is obtained, and the yield is generally 40-60%.

As one possible embodiment, the primary amine-containing copolymer may be prepared according to the following preparation procedure:

①

the preparation method of the compound 3 specifically comprises the following steps: dissolving 4-chloromethyl styrene and potassium phthaloyl in N, N-dimethylformamide, stirring at room temperature for 20-30 hours, adding the solution into aqueous sodium hydroxide solution (0.8-1.2 mol/L) to obtain precipitate, filtering, dissolving the filter residue in ethyl acetate, filtering to obtain insoluble substances as white salt, rotationally evaporating the filtrate to obtain yellow solid, and finally recrystallizing in methanol to obtain the compound 3.

②

The preparation method of the phthaloyl-containing copolymer specifically comprises the following steps: dissolving styrene and compound 3 in 1, 4-dioxane; under the protection of nitrogen, azodiisobutyronitrile is added, then the temperature is raised to 60 ℃ to 80 ℃ and stirred for 20 to 30 hours, wherein the mol ratio of the styrene to the compound 3 is (1 to 9) to 1; the mass of the azodiisobutyronitrile is 1.0-3.0% of the total mass of the styrene and the compound 3; the mass of the 1, 4-dioxane is 10 to 30 times of the total mass of the styrene and the compound 3.

After cooling to room temperature, the solution is dripped into the stirred methanol solution to obtain white phthaloyl-containing copolymer solid, and the phthaloyl-containing copolymer is obtained after filtration and drying, wherein the yield is 40% -60%.

③

The preparation method of the primary amine-containing copolymer specifically comprises the following steps: dissolving the copolymer containing the phthaloyl group in 1, 4-dioxane, heating to 75-85 ℃ under the protection of nitrogen, and then adding hydrazine hydrate under stirring to react for 10-15 hours, wherein the molar ratio of the hydrazine hydrate to the copolymer containing the phthaloyl group is (10-15) to 1; the mass of the 1, 4-dioxane is 10 to 30 times of that of the copolymer containing phthaloyl.

After cooling to room temperature, the reaction mixture is filtered, the filtrate is dripped into the stirred methanol solution to obtain a white solid, and the primary amine-containing copolymer is obtained after filtration and drying, and the yield is generally 40% -60%.

In the embodiment of the application, the nano precipitation method specifically includes the following steps:

step (1): the phenolic hydroxyl group-containing copolymer and the primary amine-containing copolymer are dissolved in an organic solvent to form a mixed solution. In the embodiment, the weight percentage of the phenolic hydroxyl-containing copolymer and the primary amine-containing copolymer in the raw materials is 25% -78% to 22% -75%, for example, the weight percentage of the two copolymers is 25% -75% or 36% -64% or 78% -22%. The total mass of the phenolic hydroxyl group-containing copolymer and the primary amine-containing copolymer is 0.25% to 1.40%, such as 0.25%, 0.50%, 0.60%, 1.15%, 1.20% or 1.40%, or an intermediate value between any two of the foregoing values, by mass of the organic solvent. The organic solvent is at least one of N, N-dimethylformamide and tetrahydrofuran, preferably N, N-dimethylformamide.

Step (2): and dissolving the OP-10 emulsifier in deionized water to prepare a mixed deionized water solution containing the OP-10 emulsifier. In this embodiment, the mixed deionized water solution is prepared from OP-10 emulsifier and deionized water, wherein the mass of OP-10 emulsifier is 0.1% -1.0% of the mass of the mixed deionized water solution, such as 0.1%, 0.3%, 0.5%, 0.7%, 0.9% or 1.0%, or an intermediate value between any two of the above values.

Step (3): the mixed solution is added into the mixed deionized water solution rapidly under the stirring condition, specifically in the time of not more than 3 seconds, and the mass ratio of the mixed solution to the mixed deionized water solution is (10.03-20.18) to 100; stirring at 400-1800 rpm, such as 400 rpm, 600 rpm, 700 rpm, 800 rpm, 1000 rpm, 1200 rpm, 1400 rpm, 1600 rpm or 1800 rpm, and reacting at 30-60deg.C, such as 30deg.C, 45deg.C, 50deg.C or 60deg.C; the reaction time is 2-12 hours, such as 2 hours, 4 hours, 6 hours, 8 hours, 10 hours or 12 hours, and the polymer nano particle supported acid-base synergistic catalyst is obtained.

The embodiment of the application also provides a polymer nanoparticle supported acid-base synergistic catalyst, which is prepared by adopting the preparation method of the polymer nanoparticle supported acid-base synergistic catalyst, wherein the polymer nanoparticle supported acid-base synergistic catalyst can be an aqueous solution system comprising a phenolic hydroxyl copolymer and a primary amine copolymer. The catalyst is in full contact with a substrate depending on the high specific surface area of the polymer nano particles under the condition of water. On the basis, the phenolic hydroxyl group-containing copolymer which is in weak acidity in the polymer nano-particles provides phenolic hydroxyl groups as acid sites, and forms hydrogen bond connection with carbonyl groups containing alpha-H of a substrate; the primary amine-containing copolymer, which is weakly basic, provides primary amine groups that bind to the activated substrate carbonyl groups. Meanwhile, the other carbonyl-containing substrate and the hydroxyl carried by the polymer nano-particles form hydrogen bonds to be activated, and the two activated substrates rapidly undergo aldol condensation and are separated from the polymer nano-particles, so that heterogeneous synergistic catalysis of the aldol condensation reaction of the acetone and the 4-nitrobenzaldehyde is realized.

The embodiment of the application also provides application of the polymer nanoparticle supported acid-base synergistic catalyst, which is used for catalyzing aldol condensation reaction. In practical application, the polymer nanoparticle supported acid-base synergistic catalyst is mainly used for catalyzing aldol condensation reaction of acetone and 4-nitrobenzaldehyde, and has high catalytic activity. The corresponding aldol condensation reaction method comprises the following steps: mixing polymer nano-particles loaded with acid-base synergistic catalyst (aqueous solution system) and acetone solution of 4-nitrobenzaldehyde with the molar ratio of 1: (15-25) according to the mass ratio of (2.3-9.2) to 100, and carrying out reflux reaction in nitrogen for 5-24 hours at 30-60 ℃.

The features and capabilities of the present application are described in further detail below in connection with the examples.

Example 1

The embodiment provides a polymer nanoparticle supported acid-base synergistic catalyst, which is prepared according to the following preparation method:

(1) Preparing raw materials:

phenolic hydroxyl group-containing copolymer：

Compound 1: 8.0 g of caffeic acid was dissolved in 60 ml of N, N-dimethylformamide, 13.48 g of triethylamine was then added thereto, and the mixture was stirred and heated to 100℃under nitrogen atmosphere to react for 60 minutes. After the reaction was completed, the mixture was cooled to room temperature, and was then subjected to rotary evaporation to 90℃to remove unreacted N, N-dimethylformamide and triethylamine, whereby a brown-yellow oily liquid was obtained. The yellowish oily liquid was separated by silica chromatography to give a pale yellow oily liquid, compound 1, which had a mass of 2.50 g.

Compound 2: 16.03 g of 2-tert-butyl 2-carbonate was dissolved in 15 ml of tetrahydrofuran, 225 mg of 4-dimethylaminopyridine was added as a catalyst, and 2.50 g of Compound 1 was added thereto, followed by reaction at low temperature for 12 hours. After the reaction was completed, 50 ml of an aqueous ammonium chloride solution having a mass fraction of 5% was added for washing, and after the completion of the washing, 10 ml of ethyl acetate was used for extraction, the washing and the extraction were repeated three times, the excess 2-tert-butyl carbonate in the reaction system was removed to obtain a mixed solution, finally, the ethyl acetate was removed by rotary evaporation to 40℃to obtain a dark yellow oily liquid, which was separated by silica chromatography to obtain pale yellow compound 2 having a mass of 1.92 g.

T-butyloxycarbonyl-containing copolymer: 1.61 g of styrene and 500 mg of Compound 2 were dissolved in 30 ml of 1, 4-dioxane, 63 mg of azobisisobutyronitrile were added under nitrogen protection, then heated to 80℃and stirred for 24 hours; after cooling to room temperature, the solution was added dropwise to a stirred methanol solution to obtain a white solid, and the t-butoxycarbonyl-containing copolymer was obtained after filtration and drying in 40% yield. The weight average molecular weight of the t-butoxycarbonyl-containing copolymer was 9160 as determined by gel permeation chromatography, and the value of x in the t-butoxycarbonyl-containing copolymer was 50% as determined by nuclear magnetic resonance hydrogen spectrometry.

Phenolic hydroxyl group-containing copolymer: 800 mg of the above t-butoxycarbonyl-containing copolymer (x=50%; weight average molecular weight of 9160) was dissolved in methylene chloride, 0.9 ml of trifluoroacetic acid was added, and stirred at room temperature for 12 hours; the reaction mixture was dried by spinning, tetrahydrofuran was added to dissolve, and this solution was added dropwise to stirring petroleum ether to give a light brown solid, and the precipitate was collected by filtration and dried to give a phenolic hydroxyl group-containing copolymer in a yield of 50%. The weight average molecular weight of the phenolic hydroxyl group-containing copolymer was 5000 as determined by gel permeation chromatography.

FIG. 1 is a nuclear magnetic resonance hydrogen spectrum of the phenolic hydroxyl group-containing copolymer prepared in this example, and FIG. 1 demonstrates the successful preparation of the phenolic hydroxyl group-containing copolymer, wherein the characteristic peaks at 1.27ppm and 1.66ppm are the polymer backbone hydrogens; characteristic peaks of benzene ring hydrogen at 6.62ppm and 7.04ppm are measured by nuclear magnetic resonance hydrogen spectrum, and the value of x in the phenolic hydroxyl group-containing copolymer is 50%.

Primary amine-containing copolymers：

Compound 3: dissolving 4-chloromethyl styrene and potassium phthaloyl in N, N-dimethylformamide, stirring at room temperature for 24 hours, adding the solution into 1000 ml of sodium hydroxide aqueous solution (1 mol/L) to obtain precipitate, filtering, dissolving the filter residue in ethyl acetate, filtering to obtain insoluble substances as white salt, rotary evaporating to obtain yellow solid, and recrystallizing in methanol to obtain the compound 3.

Phthaloyl-containing copolymer: 1.07 g of styrene and 900 mg of Compound 3 were dissolved in 30 ml of 1, 4-dioxane, 59 mg of azobisisobutyronitrile were added under nitrogen protection, then heated to 70℃and stirred for 24 hours; after cooling to room temperature, the solution was added dropwise to a stirred methanol solution to give a white solid, and the phthaloyl-containing copolymer was obtained after filtration and drying in 60% yield. The weight average molecular weight of the phthaloyl-containing copolymer was 13000 as determined by gel permeation chromatography, and the value of y in the phthaloyl-containing copolymer was 25% as determined by nuclear magnetic resonance hydrogen spectrometry.

Primary amine-containing copolymer: 800 mg of the phthaloyl-containing copolymer (y=25%; weight average molecular weight is 13000) was dissolved in 20 ml of 1, 4-dioxane, 0.7 ml of hydrazine hydrate was added, and the mixture was heated to 80 ℃ under the protection of nitrogen and reacted for 12 hours; after cooling to room temperature, the reaction mixture was filtered, the filter residue was a white solid, the filtrate was added dropwise to petroleum ether under stirring to give a white solid, and the precipitate was collected by filtration and dried to give a primary amine-containing copolymer in 40% yield. The weight average molecular weight of the primary amine-containing copolymer was 10000 as determined by gel permeation chromatography.

FIG. 2 is a nuclear magnetic resonance hydrogen spectrum of the primary amine-containing copolymer prepared in this example, and FIG. 2 demonstrates the successful preparation of the primary amine-containing copolymer, wherein the characteristic peaks at 1.43ppm and 1.85ppm are the polymer backbone hydrogens; characteristic peaks of benzene ring hydrogen at 6.56ppm and 7.05 ppm; 3.77ppm is the characteristic peak of hydrogen on carbon attached to amino group; the value of y in the primary amine-containing copolymer was 25% as determined by nuclear magnetic resonance hydrogen spectrometry.

(2) 5 mg of the phenolic hydroxyl group-containing copolymer (x=50%; weight average molecular weight: 5000) and 9 mg of the primary amine-containing copolymer (y=25%; weight average molecular weight: 10000) were dissolved in 2 ml of N, N-dimethylformamide to obtain a solution a.

(3) 30 mg of OP-10 emulsifier was dissolved in 10 ml of deionized water to give aqueous solution B.

(4) And adding the solution A into the aqueous solution B within 3 seconds under the condition of stirring at 60 ℃ (700 parts per minute) to form polymer nano-particles, and keeping stirring for 2 hours to obtain the polymer nano-particle supported acid-base synergistic catalyst.

Fig. 3 is a graph showing a particle size distribution of the polymer nanoparticle supported acid-base catalyst prepared in this example, and as can be seen from fig. 3, the polymer nanoparticle supported acid-base catalyst in this example is a nanoparticle with an average diameter of 60 nm.

FIG. 4 is a Fourier transform infrared spectrum of a polymer nanoparticle supported acid-base synergistic catalyst prepared in the present example, and FIG. 4 demonstrates the successful preparation of the catalyst, wherein 2923cm ^-1 And 2852cm ^-1 is-CH ₂ -a characteristic absorption peak; 3386cm ^-1 、1604cm ^-1 Is the characteristic absorption peak of N-H on primary amine; 1450cm ^-1 Is the characteristic absorption peak of benzene ring where phenolic hydroxyl is located; 700cm ^-1 The characteristic absorption peak of benzene ring is shown. The polymer nanoparticle supported acid-base synergistic catalyst is an aqueous solution dispersion system, can be directly used for catalysis, and does not need to be separated and dried, so that the steps are few and the operation is convenient.

The catalytic performance of the polymer nanoparticle-supported acid-base synergistic catalyst of this example was verified as follows.

Catalytic reaction: dissolving 30 mg of 4-nitrobenzaldehyde in 232 mg of acetone to obtain an acetone solution of the 4-nitrobenzaldehyde, adding the acetone solution of the 4-nitrobenzaldehyde into the polymer nanoparticle supported acid-base synergistic catalyst prepared in the embodiment, and carrying out reflux reaction in nitrogen at 60 ℃ for 5 hours; then adding 10 ml of ethyl acetate for extraction, separating ethyl acetate phase and rotary evaporating to obtain aldol condensation product, wherein the extracted water phase contains polymer nano-particle supported acid-base synergistic catalyst, and continuously adding acetone solution of 4-nitrobenzaldehyde for repeated use and catalysis.

The nuclear magnetic resonance hydrogen spectrum proves that the reaction product is beta-hydroxy ketone and alpha, beta-unsaturated ketone, namely, the aldol condensation product is successfully prepared, the catalytic activity of the polymer nanoparticle supported acid-base synergistic catalyst is high, and the time required for complete catalytic reaction is short; meanwhile, the polymer nanoparticle supported acid-base synergistic catalyst of the embodiment has excellent catalytic effect, and the aldol condensation conversion rate of the catalytic acetone and 4-nitrobenzaldehyde is more than 98%. In addition, the acid-base synergistic catalyst loaded by the polymer nano particles after the reaction can be continuously used, so that the catalyst has reusability, and the conversion rate of more than 90% can be achieved after the catalyst is reused for three times.

Example 2

(1) The respective raw materials were prepared in a similar manner to example 1, and a description thereof will not be repeated here.

(2) 10 mg of the phenolic hydroxyl group-containing copolymer (x=50%; weight average molecular weight: 5000) and 17 mg of the primary amine-containing copolymer (y=25%; weight average molecular weight: 10000) were dissolved in 2 ml of N, N-dimethylformamide to obtain a solution a.

(3) 100 mg of OP-10 emulsifier was dissolved in 10 ml of deionized water to give aqueous solution B.

(4) And adding the solution A into the aqueous solution B within 3 seconds under the condition of stirring at 30 ℃ (1800 rpm) to form polymer nano-particles, and keeping stirring for 2 hours to obtain the polymer nano-particle supported acid-base synergistic catalyst.

Catalytic reaction: dissolving 30 mg of 4-nitrobenzaldehyde in 290 mg of acetone to obtain an acetone solution of the 4-nitrobenzaldehyde, adding the acetone solution of the 4-nitrobenzaldehyde into the polymer nanoparticle supported acid-base synergistic catalyst prepared in the embodiment, and carrying out reflux reaction in nitrogen at 30 ℃ for 24 hours; then 10 ml of ethyl acetate is added for extraction, the ethyl acetate phase is separated and rotary evaporation is carried out to obtain aldol condensation products, and nuclear magnetic resonance hydrogen spectrum proves that the conversion rate of catalyzing aldol condensation of acetone and 4-nitrobenzaldehyde is more than 98 percent.

Example 3

(2) 2 mg of the phenolic hydroxyl group-containing copolymer (x=50%; weight average molecular weight: 5000) and 4 mg of the primary amine-containing copolymer (y=25%; weight average molecular weight: 10000) were dissolved in 1 ml of N, N-dimethylformamide to obtain a solution a.

(4) And adding the solution A into the aqueous solution B within 3 seconds under the condition of stirring at 60 ℃ (1800 rpm) to form polymer nano-particles, and keeping stirring for 2 hours to obtain the polymer nano-particle supported acid-base synergistic catalyst.

Catalytic reaction: dissolving 30 mg of 4-nitrobenzaldehyde in 232 mg of acetone to obtain an acetone solution of the 4-nitrobenzaldehyde, adding the acetone solution of the 4-nitrobenzaldehyde into the polymer nanoparticle supported acid-base synergistic catalyst prepared in the embodiment, and carrying out reflux reaction in nitrogen at 60 ℃ for 5 hours; then 10 ml of ethyl acetate was added for extraction, the ethyl acetate phase was separated and the aldol condensation product was obtained by rotary evaporation. The nuclear magnetic resonance hydrogen spectrum proves that the aldol condensation conversion rate of the catalytic acetone and 4-nitrobenzaldehyde is more than 98%.

Example 4

(3) 10 mg of OP-10 emulsifier was dissolved in 10 ml of deionized water to give aqueous solution B.

(4) And (3) under the condition of stirring at 30 ℃ (1800 rpm), rapidly adding the solution A into the aqueous solution B to form polymer nano-particles, and keeping stirring for 12 hours to obtain the polymer nano-particle supported acid-base synergistic catalyst.

Catalytic reaction: dissolving 30 mg of 4-nitrobenzaldehyde in 174 mg of acetone to obtain an acetone solution of 4-nitrobenzaldehyde, adding the acetone solution of 4-nitrobenzaldehyde into the polymer nanoparticle-supported acid-base synergistic catalyst prepared in the embodiment, and carrying out reflux reaction in nitrogen at 30 ℃ for 24 hours; then 10 ml of ethyl acetate was added for extraction, the ethyl acetate phase was separated and the aldol condensation product was obtained by rotary evaporation. The nuclear magnetic resonance hydrogen spectrum proves that the aldol condensation conversion rate of the catalytic acetone and 4-nitrobenzaldehyde is more than 98%.

Example 5

(1) Preparing raw materials:

phenolic hydroxyl group-containing copolymer：

Compound 1: 8.0 g of caffeic acid was dissolved in 60 ml of N, N-dimethylformamide, 13.48g of triethylamine was then added thereto, and the mixture was stirred and heated to 100℃under nitrogen atmosphere to react for 60 minutes. After the reaction was completed, the mixture was cooled to room temperature, and was then subjected to rotary evaporation to 90℃to remove unreacted N, N-dimethylformamide and triethylamine, whereby a brown-yellow oily liquid was obtained. The yellowish oily liquid was separated by silica chromatography to give a pale yellow oily liquid, compound 1, which had a mass of 2.50 g.

Compound 2: 16.03 g of 2-tert-butyl 2-carbonate was dissolved in 15 ml of tetrahydrofuran, 225 mg of 4-dimethylaminopyridine was added as a catalyst, and 2.50 g of Compound 1 was added thereto, followed by reaction at low temperature for 12 hours. After the reaction was completed, 50 ml of an aqueous ammonium chloride solution having a mass fraction of 5% was added for washing, and after the completion of the washing, 10 ml of ethyl acetate was used for extraction, the washing and the extraction were repeated three times, the excess 2-tert-butyl carbonate in the reaction system was removed to obtain a mixed solution, and finally, the ethyl acetate was removed by rotary evaporation to 40℃to obtain a dark yellow oily liquid, which was passed through a silica column to obtain pale yellow compound 2 having a mass of 1.92 g.

T-butyloxycarbonyl-containing copolymer: 1.61 g of styrene and 610 mg of Compound 2 were dissolved in 30 ml of 1, 4-dioxane, 22 mg of azobisisobutyronitrile were added under nitrogen protection, then heated to 60℃and stirred for 24 hours; after cooling to room temperature, the solution was added dropwise to a stirred methanol solution to obtain a white solid, and the t-butoxycarbonyl-containing copolymer was obtained after filtration and drying in 55% yield. The weight average molecular weight of the t-butoxycarbonyl-containing copolymer was 180000 as determined by gel permeation chromatography, and the value of x in the t-butoxycarbonyl-containing copolymer was 45% as determined by nuclear magnetic resonance hydrogen spectrometry.

Phenolic hydroxyl group-containing copolymer: 900 mg of the above t-butoxycarbonyl-containing copolymer (x=45%; weight average molecular weight is 180000) was dissolved in methylene chloride, 0.9 ml of trifluoroacetic acid was added, and stirred at room temperature for 12 hours; the reaction mixture was dried by spinning, tetrahydrofuran was added to dissolve, and this solution was added dropwise to stirring petroleum ether to give a light brown solid, and the precipitate was collected by filtration and dried to give a phenolic hydroxyl group-containing copolymer in a yield of 60%. The weight average molecular weight of the phenolic hydroxyl group-containing copolymer was 100000 as determined by gel permeation chromatography, and the value of x in the phenolic hydroxyl group-containing copolymer was 45% as determined by nuclear magnetic resonance hydrogen spectrometry.

Primary amine-containing copolymers：

Phthaloyl-containing copolymer: 1.42 g of styrene and 400 mg of Compound 3 are dissolved in 30 ml of 1, 4-dioxane, 18 mg of azobisisobutyronitrile are added under nitrogen protection, then the temperature is raised to 60℃and stirred for 24 hours; after cooling to room temperature, the solution was added dropwise to a stirred methanol solution to give a white solid, and the phthaloyl-containing copolymer was obtained after filtration and drying in 60% yield. The weight average molecular weight of the phthaloyl-containing copolymer was 115000 as determined by gel permeation chromatography, and the value of y in the phthaloyl-containing copolymer was 10% as determined by nuclear magnetic resonance hydrogen spectrometry.

Primary amine-containing copolymer: 800 mg of the phthaloyl-containing copolymer (y=10%; weight average molecular weight is 115000) was dissolved in 20 ml of 1, 4-dioxane, 0.35 ml of hydrazine hydrate was added, and the mixture was heated to 80 ℃ under the protection of nitrogen and reacted for 12 hours; after cooling to room temperature, the reaction mixture was filtered, the filter residue was a white solid, the filtrate was added dropwise to petroleum ether under stirring to give a pale yellow solid, the precipitate was collected by filtration and dried to give a primary amine-containing copolymer in 50% yield. The weight average molecular weight of the primary amine-containing copolymer was 100000 as determined by gel permeation chromatography, and the value of y in the primary amine-containing copolymer was 10% as determined by nuclear magnetic resonance hydrogen spectrometry.

(2) 2 mg of the phenolic hydroxyl group-containing copolymer (x=45%; weight average molecular weight: 100000) and 6 mg of the primary amine-containing copolymer (y=10%; weight average molecular weight: 100000) were dissolved in 2 ml of tetrahydrofuran to obtain a solution A.

(4) And adding the solution A into the aqueous solution B within 3 seconds under the condition of stirring at 45 ℃ (700 revolutions per minute) to form polymer nano-particles, and keeping stirring for 6 hours to obtain the polymer nano-particle supported acid-base synergistic catalyst.

Catalytic reaction: dissolving 30 mg of 4-nitrobenzaldehyde in 232 mg of acetone to obtain an acetone solution of the 4-nitrobenzaldehyde, adding the acetone solution of the 4-nitrobenzaldehyde into the polymer nanoparticle supported acid-base synergistic catalyst prepared in the embodiment, and carrying out reflux reaction in nitrogen at 45 ℃ for 12 hours; then 10 ml of ethyl acetate was added for extraction, the ethyl acetate phase was separated and the aldol condensation product was obtained by rotary evaporation. The nuclear magnetic resonance hydrogen spectrum proves that the aldol condensation conversion rate of the catalytic acetone and 4-nitrobenzaldehyde is more than 98%.

Example 6

(1) Preparing raw materials:

phenolic hydroxyl group-containing copolymer：

Compound 1: 8.0 g of caffeic acid was dissolved in 60 ml of N, N-dimethylformamide, 13.48 g of triethylamine was then added thereto, and the mixture was stirred and heated to 100℃under nitrogen atmosphere to react for 60 minutes. After the reaction was completed, the mixture was cooled to room temperature, and was then subjected to rotary evaporation to 90℃to remove unreacted N, N-dimethylformamide and triethylamine, whereby a brown-yellow oily liquid was obtained. The yellowish oily liquid was passed through a silica column to give a pale yellow oily liquid, namely, compound 1, which had a mass of 2.50 g.

T-butyloxycarbonyl-containing copolymer: 760 mg of styrene and 1.05 g of Compound 2 are dissolved in 30 ml of 1, 4-dioxane, 54 mg of azobisisobutyronitrile are added under nitrogen protection, then the temperature is raised to 80℃and stirred for 24 hours; after cooling to room temperature, the solution was added dropwise to a stirred methanol solution to obtain a white solid, and the t-butoxycarbonyl-containing copolymer was obtained after filtration and drying in 60% yield. The weight average molecular weight of the t-butoxycarbonyl-containing copolymer was 7600 as determined by gel permeation chromatography, and the value of x in the t-butoxycarbonyl-containing copolymer was 30% as determined by nuclear magnetic resonance hydrogen spectrometry.

Phenolic hydroxyl group-containing copolymer: 900 mg of the above t-butoxycarbonyl-containing copolymer (x=30%; weight average molecular weight 7600) was dissolved in methylene chloride, 0.7 ml of trifluoroacetic acid was added, and stirred at room temperature for 12 hours; the reaction mixture was dried by spinning, tetrahydrofuran was added for dissolution, and this solution was added dropwise to stirred petroleum ether to give a light brown solid, i.e., a phenolic hydroxyl group-containing copolymer. The precipitate was collected by filtration and dried to give a phenolic hydroxyl group-containing copolymer in 40% yield. The weight average molecular weight of the phenolic hydroxyl group-containing copolymer was 5000 as determined by gel permeation chromatography, and the value of x in the phenolic hydroxyl group-containing copolymer was 30% as determined by nuclear magnetic resonance hydrogen spectrometry.

Primary amine-containing copolymers：

Phthaloyl-containing copolymer: 1.19 g of styrene and 900 mg of Compound 3 were dissolved in 30 ml of 1, 4-dioxane, 63 mg of azobisisobutyronitrile were added under nitrogen protection, then heated to 70℃and stirred for 24 hours; after cooling to room temperature, the solution was added dropwise to a stirred methanol solution to give a white solid, and the phthaloyl-containing copolymer was obtained after filtration and drying in 50% yield. The weight average molecular weight of the phthaloyl-containing copolymer was 12000 as determined by gel permeation chromatography, and the value of y in the phthaloyl-containing copolymer was 19% as determined by nuclear magnetic resonance hydrogen spectrometry.

Primary amine-containing copolymer: 800 mg of the phthaloyl-containing copolymer (y=19%; weight average molecular weight is 12000) was dissolved in 20 ml of 1, 4-dioxane, 0.7 ml of hydrazine hydrate was added, and the mixture was heated to 80 ℃ under the protection of nitrogen and reacted for 12 hours; the reaction mixture was filtered, the filter residue was a white solid, the filtrate was added dropwise to stirred petroleum ether to obtain a pale yellow solid, and the precipitate was collected by filtration and dried to obtain a primary amine-containing copolymer in a yield of 60%. The weight average molecular weight of the primary amine-containing copolymer was 10000 as determined by gel permeation chromatography, and the value of y in the primary amine-containing copolymer was 19% as determined by nuclear magnetic resonance hydrogen spectrometry.

(2) 4 mg of the phenolic hydroxyl group-containing copolymer (x=30%; weight average molecular weight: 5000) and 6 mg of the primary amine-containing copolymer (y=19%; weight average molecular weight: 10000) were dissolved in 2 ml of N, N-dimethylformamide to obtain a solution a.

(4) And adding the solution A into the aqueous solution B within 3 seconds under the condition of stirring at 30 ℃ (700 revolutions per minute) to form polymer nano-particles, and keeping stirring for 2 hours to obtain the polymer nano-particle supported acid-base synergistic catalyst.

Catalytic reaction: dissolving 30 mg of 4-nitrobenzaldehyde in 232 mg of acetone to obtain an acetone solution of the 4-nitrobenzaldehyde, adding the acetone solution of the 4-nitrobenzaldehyde into the polymer nanoparticle supported acid-base synergistic catalyst prepared in the embodiment, and carrying out reflux reaction in nitrogen at 30 ℃ for 24 hours; then 10 ml of ethyl acetate was added for extraction, the ethyl acetate phase was separated and the aldol condensation product was obtained by rotary evaporation. The nuclear magnetic resonance hydrogen spectrum proves that the aldol condensation conversion rate of the catalytic acetone and 4-nitrobenzaldehyde is more than 98%.

Example 7

(1) The respective raw materials were prepared in a similar manner to example 6, and a description thereof will not be repeated here.

(4) And adding the solution A into the aqueous solution B within 3 seconds under the condition of stirring at 60 ℃ (400 revolutions per minute) to form polymer nano-particles, and keeping stirring for 12 hours to obtain the polymer nano-particle supported acid-base synergistic catalyst.

Catalytic reaction: dissolving 30 mg of 4-nitrobenzaldehyde in 232 mg of acetone to obtain an acetone solution of the 4-nitrobenzaldehyde, adding the acetone solution of the 4-nitrobenzaldehyde into the polymer nanoparticle supported acid-base synergistic catalyst prepared in the embodiment, and carrying out reflux reaction in nitrogen at 60 ℃ for 5 hours; then 10 ml of ethyl acetate is added for extraction, the ethyl acetate phase is separated and rotary evaporation is carried out to obtain aldol condensation products, and nuclear magnetic resonance hydrogen spectrum proves that the conversion rate of catalyzing aldol condensation of acetone and 4-nitrobenzaldehyde is more than 98 percent.

Example 8

(3) 50 mg of OP-10 emulsifier was dissolved in 10 ml of deionized water to give aqueous solution B.

(4) And adding the solution A into the aqueous solution B within 3 seconds under the condition of stirring at 60 ℃ (1800 rpm) to form polymer nano-particles, and keeping stirring for 12 hours to obtain the polymer nano-particle supported acid-base synergistic catalyst.

Example 9

(1) Preparing raw materials:

phenolic hydroxyl group-containing copolymer：

Boc copolymer: 1.48 g of styrene and 530 mg of Compound 2 were dissolved in 30 ml of 1, 4-dioxane, 40 mg of azobisisobutyronitrile were added under nitrogen protection, then heated to 70℃and stirred for 24 hours; after cooling to room temperature, the solution was added dropwise to a stirred methanol solution to obtain a white solid, and the t-butoxycarbonyl-containing copolymer was obtained after filtration and drying in 60% yield. The weight average molecular weight of the t-butoxycarbonyl-containing copolymer was 95000 as determined by gel permeation chromatography, and the value of x in the t-butoxycarbonyl-containing copolymer was 10% as determined by nuclear magnetic resonance hydrogen spectrometry.

Phenolic hydroxyl group-containing copolymer: 900 mg of the above t-butoxycarbonyl-containing copolymer (x=10%; weight average molecular weight: 95000) was dissolved in methylene chloride, 0.4 ml of trifluoroacetic acid was added, and stirred at room temperature for 12 hours; the reaction mixture was dried by spinning, tetrahydrofuran was added for dissolution, and this solution was added dropwise to stirred petroleum ether to give a light brown solid, i.e., a phenolic hydroxyl group-containing copolymer. The precipitate was collected by filtration and dried to give a phenolic hydroxyl group-containing copolymer in a yield of 50%. The weight average molecular weight of the phenolic hydroxyl group-containing copolymer was 80000 as determined by gel permeation chromatography, and the value of x in the hydroxyl group-containing copolymer was 10% as determined by nuclear magnetic resonance hydrogen spectrometry.

Primary amine-containing copolymers：

Phthaloyl-containing copolymer: 1.60 g of styrene and 500 mg of Compound 3 are dissolved in 30 ml of 1, 4-dioxane, 63 mg of azobisisobutyronitrile are added under nitrogen protection, then the temperature is raised to 80℃and stirred for 24 hours; after cooling to room temperature, the solution was added dropwise to a stirred methanol solution to give a white solid, and the phthaloyl-containing copolymer was obtained after filtration and drying in 40% yield. The weight average molecular weight of the phthaloyl-containing copolymer was 5700 as determined by gel permeation chromatography and the value of y in the phthaloyl-containing copolymer was 11% as determined by nuclear magnetic resonance hydrogen spectroscopy.

Primary amine-containing copolymer: 800 mg of the phthaloyl-containing copolymer (y=11%; weight average molecular weight: 5700) was dissolved in 20 ml of 1, 4-dioxane, 0.4 ml of hydrazine hydrate was added, and the mixture was heated to 80 ℃ under nitrogen protection and reacted for 12 hours; the reaction mixture was filtered, the filter residue was a white solid, the filtrate was added dropwise to stirred petroleum ether to obtain a pale yellow solid, and the precipitate was collected by filtration and dried to obtain a primary amine-containing copolymer in a yield of 60%. The weight average molecular weight of the primary amine-containing copolymer was 5000 as determined by gel permeation chromatography, and the value of y in the primary amine-containing copolymer was 11% as determined by nuclear magnetic resonance hydrogen spectrometry.

(2) 18 mg of the phenolic hydroxyl group-containing copolymer (x=10%; weight average molecular weight: 80000) and 6 mg of the primary amine-containing copolymer (y=11%; weight average molecular weight: 5000) were dissolved in 2 ml of tetrahydrofuran, to obtain a solution a.

(4) And adding the solution A into the aqueous solution B within 3 seconds under the condition of stirring at 50 ℃ (700 revolutions per minute) to form polymer nano-particles, and keeping stirring for 2 hours to obtain the polymer nano-particle supported acid-base synergistic catalyst.

Catalytic reaction: dissolving 30 mg of 4-nitrobenzaldehyde in 232 mg of acetone to obtain an acetone solution of the 4-nitrobenzaldehyde, adding the acetone solution of the 4-nitrobenzaldehyde into the polymer nanoparticle-supported acid-base synergistic catalyst prepared in the embodiment, and carrying out reflux reaction in nitrogen at 50 ℃ for 10 hours; then 10 ml of ethyl acetate was added for extraction, the ethyl acetate phase was separated and the aldol condensation product was obtained by rotary evaporation. The nuclear magnetic resonance hydrogen spectrum proves that the aldol condensation conversion rate of the catalytic acetone and 4-nitrobenzaldehyde is more than 98%.

Example 10

(1) Preparing raw materials:

phenolic hydroxyl group-containing copolymer：

T-butyloxycarbonyl-containing copolymer: 1.48 g of styrene and 530 mg of Compound 2 were dissolved in 30 ml of 1, 4-dioxane, 40 mg of azobisisobutyronitrile were added under nitrogen protection, then heated to 70℃and stirred for 24 hours; after cooling to room temperature, the solution was added dropwise to a stirred methanol solution to obtain a white solid, and the t-butoxycarbonyl-containing copolymer was obtained after filtration and drying in 60% yield. The weight average molecular weight of the t-butoxycarbonyl-containing copolymer was 95000 as determined by gel permeation chromatography, and the value of x in the t-butoxycarbonyl-containing copolymer was 10% as determined by nuclear magnetic resonance hydrogen spectrometry.

Phenolic hydroxyl group-containing copolymer: 900 mg of the above t-butoxycarbonyl-containing copolymer (x=10%; weight average molecular weight: 95000) was dissolved in methylene chloride, 0.4 ml of trifluoroacetic acid was added, and stirred at room temperature for 12 hours; the reaction mixture was dried by spinning, tetrahydrofuran was added for dissolution, and this solution was added dropwise to stirred petroleum ether to give a light brown solid, i.e., a phenolic hydroxyl group-containing copolymer. The precipitate was collected by filtration and dried to give a phenolic hydroxyl group-containing copolymer in a yield of 60%. The weight average molecular weight of the phenolic hydroxyl group-containing copolymer was 80000 as determined by gel permeation chromatography, and the value of x in the hydroxyl group-containing copolymer was 10% as determined by nuclear magnetic resonance hydrogen spectrometry.

Primary amine-containing copolymers：

Phthaloyl-containing copolymer: 0.52 g of styrene and 1.32 g of Compound 3 are dissolved in 30 ml of 1, 4-dioxane, 19 mg of azobisisobutyronitrile are added under nitrogen protection, then the temperature is raised to 60℃and stirred for 24 hours; after cooling to room temperature, the solution was added dropwise to a stirred methanol solution to give a white solid, and the phthaloyl-containing copolymer was obtained after filtration and drying in 50% yield. The weight average molecular weight of the phthaloyl-containing copolymer was 160000 as determined by gel permeation chromatography, and the value of y in the phthaloyl-containing copolymer was 50% as determined by nuclear magnetic resonance hydrogen spectrometry.

Primary amine-containing copolymer: 800 mg of the phthaloyl-containing copolymer (y=50%; weight average molecular weight is 160000) was dissolved in 20 ml of 1, 4-dioxane, 1.5 ml of hydrazine hydrate was added, and the mixture was heated to 80 ℃ under nitrogen protection and reacted for 12 hours; after cooling to room temperature, the reaction mixture was filtered, the filter residue was a white solid, the filtrate was added dropwise to petroleum ether under stirring to give a pale yellow solid, the precipitate was collected by filtration and dried to give a primary amine-containing copolymer in 50% yield. The weight average molecular weight of the primary amine-containing copolymer was 100000 as determined by gel permeation chromatography, and the value of y in the primary amine-containing copolymer was 50% as determined by nuclear magnetic resonance hydrogen spectrometry.

(2) 18 mg of the phenolic hydroxyl group-containing copolymer (x=10%; weight average molecular weight: 80000) and 5 mg of the primary amine-containing copolymer (y=50%; weight average molecular weight: 100000) were dissolved in 2 ml of tetrahydrofuran, to obtain a solution a.

Comparative example 1

This comparative example provides a polymer nanoparticle supported acid catalyst prepared in substantially the same manner as in example 1, except that: in this comparative example, 6 mg of a phenolic hydroxyl group-containing copolymer (x=50%; weight average molecular weight: 5000) was dissolved in 2 ml of N, N-dimethylformamide to obtain a solution a.

30 mg of OP-10 emulsifier was dissolved in 10 ml of deionized water to give aqueous solution B.

And adding the solution A into the aqueous solution B in 3 seconds under the condition of stirring at 60 ℃ (700 revolutions per minute) to form polymer nano-particles, and keeping stirring for 2 hours to obtain the polymer nano-particle supported acid synergistic catalyst.

Catalytic reaction: dissolving 30 mg of 4-nitrobenzaldehyde in 232 mg of acetone to obtain an acetone solution of 4-nitrobenzaldehyde, adding the acetone solution of 4-nitrobenzaldehyde into the polymer nanoparticle supported acid and catalyst prepared in the comparative example, and reacting for 24 hours at 60 ℃ in nitrogen; then 10 ml of ethyl acetate was added for extraction, the ethyl acetate phase was separated and the aldol condensation product was obtained by rotary evaporation. The nuclear magnetic resonance hydrogen spectrum confirms the conversion rate of the aldol condensation of the catalytic acetone and the 4-nitrobenzaldehyde. The ethyl acetate phase is separated and rotary evaporated to give the aldol condensation product. The nuclear magnetic resonance hydrogen spectrum proves that the aldol condensation conversion rate of the catalytic acetone and 4-nitrobenzaldehyde is lower than 20%.

Comparative example 2

This comparative example provides a polymer nanoparticle supported base catalyst prepared in substantially the same manner as in example 1, except that: in this comparative example, 9 mg of a primary amine-containing copolymer (x=25%; weight average molecular weight: 10000) was dissolved in 2 ml of N, N-dimethylformamide to obtain a solution a.

And adding the solution A into the aqueous solution B in 3 seconds under the condition of stirring at 60 ℃ (700 revolutions per minute) to form polymer nano-particles, and keeping stirring for 2 hours to obtain the polymer nano-particle supported base synergistic catalyst.

Catalytic reaction: dissolving 30 mg of 4-nitrobenzaldehyde in 232 mg of acetone to obtain an acetone solution of 4-nitrobenzaldehyde, adding the acetone solution of 4-nitrobenzaldehyde into the polymer nanoparticle-supported base catalyst prepared in the comparative example, and carrying out reflux reaction in nitrogen at 60 ℃ for 24 hours; then 10 ml of ethyl acetate was added for extraction, the ethyl acetate phase was separated and the aldol condensation product was obtained by rotary evaporation. The nuclear magnetic resonance hydrogen spectrum proves that the aldol condensation conversion rate of the catalytic acetone and 4-nitrobenzaldehyde is 35 percent.

In conclusion, the preparation method of the polymer nanoparticle supported acid-base synergistic catalyst is simple, convenient and controllable, and is easy for mass production; the polymer nanoparticle supported acid-base synergistic catalyst has high catalytic activity on aldol condensation reaction of acetone and 4-nitrobenzaldehyde.

The foregoing is merely exemplary embodiments of the present application and is not intended to limit the scope of the present application, and various modifications and variations may be suggested to one skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. The preparation method of the polymer nanoparticle supported acid-base synergistic catalyst is characterized in that raw materials comprising a phenolic hydroxyl copolymer and a primary amine copolymer are selected to be prepared by a nano precipitation method, and the dosage ratio of the phenolic hydroxyl copolymer to the primary amine copolymer in the raw materials is (25% -78%) to (22% -75%) in percentage by mass; wherein the molecular structural formulas of the phenolic hydroxyl group-containing copolymer and the primary amine-containing copolymer are respectively

2. The method for preparing the polymer nanoparticle supported acid-base synergistic catalyst according to claim 1, wherein the nano precipitation method specifically comprises the following steps:

dissolving the phenolic hydroxyl group-containing copolymer and the primary amine-containing copolymer in an organic solvent to form a mixed solution;

and under the stirring condition, adding the mixed solution into the mixed deionized water solution containing the OP-10 emulsifier, and reacting to obtain the polymer nanoparticle supported acid-base synergistic catalyst.

3. The method for preparing the polymer nanoparticle supported acid-base synergistic catalyst according to claim 2, wherein the total mass of the phenolic hydroxyl group-containing copolymer and the primary amine-containing copolymer is 0.25% -1.40% of the mass of the organic solvent;

4. The method for preparing the polymer nanoparticle supported acid-base synergistic catalyst according to claim 2, wherein the stirring speed is 400-1800 rpm;

and/or, the temperature of the reaction is 30-60 ℃;

and/or the reaction time is 2-12 hours.

5. The method for preparing the polymer nanoparticle supported acid-base synergistic catalyst according to claim 2, wherein the mixed solution is added to the mixed deionized water solution in a mass ratio of (10.03-20.18) to 100 in not more than 3 seconds.

6. A polymer nanoparticle supported acid-base synergistic catalyst, which is prepared by the preparation method of the polymer nanoparticle supported acid-base synergistic catalyst according to any one of claims 1 to 5.

7. The use of the polymer nanoparticle supported acid-base synergistic catalyst as claimed in claim 6, wherein the polymer nanoparticle supported acid-base synergistic catalyst is used for catalyzing aldol condensation reaction.

8. The use of the polymer nanoparticle supported acid-base co-catalyst according to claim 7, wherein the polymer nanoparticle supported acid-base co-catalyst is used for catalyzing an aldol condensation reaction of 4-nitrobenzaldehyde and acetone, and the aldol condensation reaction comprises the following steps:

mixing the polymer nanoparticle supported acid-base synergistic catalyst with the acetone solution of 4-nitrobenzaldehyde according to the mass ratio of (2.3-9.2) to 100, and carrying out reflux reaction in nitrogen for 5-24 hours at the temperature of 30-60 ℃.