阅读说明：本技术 一种双金属负载复合催化剂及其催化合成对氨基苯乙炔的方法 (Bimetal loaded composite catalyst and method for catalytic synthesis of p-aminophenylacetylene by using same ) 是由 高铁军 汪友谊 于 2019-12-05 设计创作，主要内容包括：本发明公开了一种双金属负载复合催化剂及其催化合成对氨基苯乙炔的方法,其中双金属负载复合催化剂为壳聚糖/Fe<Sub>3</Sub>O<Sub>4</Sub>-Pd/Cu复合负载催化剂,是首先由改性壳聚糖包裹磁性材料Fe<Sub>3</Sub>O<Sub>4</Sub>形成带有磁性的壳聚糖/Fe<Sub>3</Sub>O<Sub>4</Sub>复合载体,再通过浸渍法将钯和铜负载在载体上,形成的具有磁性的双金属负载复合催化剂。本发明中使用了壳聚糖包裹磁性内核,不仅提了载体的机械强度,还可以通过磁性使得催化剂快速分离。应用磁性分离技术,可以快速分离细小磁性颗粒,因此,可以将载体颗粒做到微米级甚至纳米级,这样可以极大增加载体的比表面积和负载能力,极大提高催化效率。(The invention discloses a bimetal loaded composite catalyst and a method for catalytic synthesis of p-aminophenylacetylene by using the same, wherein the bimetal loaded composite catalyst is chitosan/Fe 3 O 4 the-Pd/Cu composite supported catalyst is prepared by coating magnetic material Fe with modified chitosan 3 O 4 Form magnetic chitosan/Fe 3 O 4 And (3) compounding the carrier, and then loading palladium and copper on the carrier by an impregnation method to form the magnetic bimetallic supported composite catalyst. According to the invention, the chitosan is used for coating the magnetic core, so that the mechanical strength of the carrier is improved, and the catalyst can be quickly separated through magnetism. By applying the magnetic separation technology, the fine magnetic particles can be quickly separated, so that the carrier particles can be made into micron-sized or even nano-sized particles, the specific surface area and the loading capacity of the carrier can be greatly increased, and the catalytic efficiency is greatly improved.)

1. A bimetallic supported composite catalyst characterized by:

the bimetal loaded composite catalyst is chitosan/Fe₃O₄the-Pd/Cu composite supported catalyst is prepared by coating magnetic material Fe with modified chitosan₃O₄Form magnetic chitosan/Fe₃O₄And (3) compounding the carrier, and then loading palladium and copper on the carrier by an impregnation method to form the magnetic bimetallic supported composite catalyst.

2. The bimetal supported composite catalyst according to claim 1, characterized by being prepared by a method comprising the steps of:

step 1: preparation of composite Carrier

1a, weighing a proper amount of chitosan and a pore-forming agent, dissolving the chitosan and the pore-forming agent in 1-3% acetic acid solution, stirring and dissolving, and slowly dripping aldehyde solution for crosslinking reaction; after the reaction is finished, adding the ground fine Fe into the reaction system₃O₄Granulating and uniformly stirring;

1b, preparing NaOH or KOH alcoholic solution, uniformly injecting the mixed solution obtained in the step 1a into the NaOH or KOH alcoholic solution through an injector, and curing into uniform spherical particles to obtain Fe coated by chitosan₃O₄Filtering, washing with deionized water and ethanol, drying, and storing in ethanol solution;

step 2: Chitosan/Fe₃O₄Preparation of-Pd/Cu

2a, weighing a proper amount of CuI, adding distilled water and a proper amount of NaI, stirring for dissolving, adding a proper amount of palladium acetate, and stirring uniformly;

2b, coating the chitosan obtained in the step 1b with Fe₃O₄Adding the particles into the solution obtained in step 2a, continuously stirring, heating, concentrating, adsorbing for 1-2 hr, filtering, and drying under nitrogen protection to obtain black particles, i.e. chitosan/Fe₃O₄-a Pd/Cu composite catalyst.

3. The bimetallic supported composite catalyst of claim 2, characterized in that:

in the step 1a, the molecular weight of the chitosan is 3-20 ten thousand, the deacetylation degree is 70% -95%, and the mass concentration of the dissolved chitosan in the system is 5-20%; the pore-foaming agent is selected from urea, polyvinylpyrrolidone or polyethylene glycol, and the amount of the pore-foaming agent is 2-15% of the mass of the chitosan; the aldehyde is selected from formaldehyde, acetaldehyde, benzaldehyde, glutaraldehyde or salicylaldehyde and the like, and is preferably salicylaldehyde; the concentration of the aldehyde solution is controlled between 5 and 15 percent.

4. The bimetallic supported composite catalyst of claim 2, characterized in that:

in the step 1a, when the chitosan and the aldehyde are subjected to crosslinking reaction, the crosslinking degree is controlled to be 1-10%, and the crosslinking time is controlled to be 2-8 hours.

5. The bimetallic supported composite catalyst of claim 2, characterized in that:

in the step 2a, the concentration of CuI is kept between 0.01 and 0.2 mol/L; the molar weight of the palladium acetate is 10-50% of the CuI.

6. The bimetallic supported composite catalyst of claim 1 or 2, characterized in that:

the loading range of the bimetal in the bimetal loaded composite catalyst is as follows: calculated by CuI, the mass ratio of the CuI to the composite carrier is 0.5-5%, and Cu: pd molar ratio is 10: 1-2: 1.

7. the method for catalytic synthesis of p-aminophenylacetylene by using the bimetallic supported composite catalyst as claimed in claim 1, which is characterized in that: taking p-aminoiodobenzene and R-based acetylene as raw materials, carrying out Sonogashira reaction under the action of a composite catalyst to generate 4-R-based ethynylaniline, and removing the R group to obtain a target product, namely p-aminophenylacetylene; the synthetic route is as follows:

8. the method of claim 7, comprising the steps of:

step 1: synthesis of 4-R-ethynyl aniline

Dissolving p-aminoiodobenzene and R-acetylene in a solvent in a nitrogen atmosphere, adding a composite catalyst and a proper amount of alkali, and stirring for reaction; after the reaction is finished, filtering the catalyst, adding a proper amount of diethyl ether, and respectively using 1mol/L NH₄Washing Cl and saturated saline solution, collecting an organic phase, drying the organic phase through anhydrous sodium sulfate, and removing a solvent to obtain a crude product of 4-R-based ethynylaniline;

step 2: synthesis of p-aminophenylacetylene

And (2) dissolving the 4-R-ethynyl aniline obtained in the step (1) in a solvent, adding an R-removing reagent, stirring at room temperature for reaction, removing the solvent after the reaction is finished, and recrystallizing to obtain a light brown solid product, namely the target product.

9. The method of claim 8, wherein:

in the step 1, the structural formula of the R-based acetylene is C ≡ C-R, wherein R is trimethylsilyl, triethylsilyl, triisopropylsilyl, tributyltin and the like;

the catalyst is calculated by uniformly loading palladium and copper, the catalytic amount of the palladium is kept to be 1 mol% -5 mol% of the p-aminoiodobenzene, and the molar ratio of the p-aminoiodobenzene to the R-acetylene is controlled to be 1: 0.5-2.

10. The method of claim 8, wherein:

in the step 2, the R group removing reagent is selected from cesium fluoride, tetrabutylammonium fluoride, cesium carbonate or potassium carbonate, and the dosage of the R group removing reagent is 0.5-3eq of the molar weight of 4-R-ethynyl aniline.

Technical Field

The invention belongs to the technical field of compound preparation, and particularly relates to a bimetallic supported composite catalyst and a method for catalytic synthesis of p-aminophenylacetylene by the bimetallic supported composite catalyst.

Background

Phenylacetylene and derivatives thereof are important intermediates in organic synthesis and also important industrial raw materials. The p-aminophenylacetylene as a key intermediate has a plurality of applications in the aspects of synthesizing high polymers, biomedicines, liquid crystal display and the like. Up to now, the synthesis of p-aminophenylacetylene by various means, such as utilizing Wittig reaction to synthesize alkyne from aldehyde, is an effective method for synthesizing p-aminophenylacetylene, but the experimental conditions have higher requirements and the operation is complicated. The synthesis of p-aminophenylacetylene by using Vilsmeier reaction is also a common method, for example, Wanghao and the like use p-nitroacetophenone as a raw material, construct molecules containing substituted olefinic bonds by Vilsmeier reaction, and obtain the p-aminophenylacetylene by multiple steps of reaction. The Sonogashira reaction is a classical reaction for realizing the coupling of terminal alkyne and aryl halide, has mild reaction conditions, simple and convenient operation and high yield, and is a very feasible path for synthesizing aromatic alkyne by utilizing the Sonogashira reaction. The Sonogashira reaction is a homogeneous catalytic reaction of noble metal palladium and copper double catalysts in the presence of organic ligands. The separation and recovery of the noble metal catalyst and the expensive ligand is a major factor that limits the industrial production thereof.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a bimetallic supported composite catalyst and a method for catalytically synthesizing p-aminophenylacetylene by the bimetallic supported composite catalyst. The invention adopts Sonogashira reaction, and utilizes the novel supported catalyst to catalyze halogenated aromatic hydrocarbon and end-position alkyne to efficiently synthesize p-aminophenylacetylene, and realizes simple and convenient recovery and circulation of the catalyst and ligand.

The bimetal supported composite catalyst of the invention is chitosan/Fe₃O₄the-Pd/Cu composite supported catalyst is prepared by coating magnetic material Fe with modified chitosan₃O₄Form magnetic chitosan/Fe₃O₄And (3) compounding the carrier, and then loading palladium and copper on the carrier by an impregnation method to form the magnetic bimetallic supported composite catalyst.

The bimetal supported composite catalyst is prepared by the method comprising the following steps:

step 1: preparation of composite Carrier

1a, weighing a proper amount of chitosan and a pore-forming agent, dissolving the chitosan and the pore-forming agent in 1-3% acetic acid solution, stirring and dissolving, and slowly dripping aldehyde solution for crosslinking reaction; after the reaction is finished, adding the ground fine Fe into the reaction system₃O₄The particles (diameter is 10-1000 μm) are stirred uniformly;

1b, preparing NaOH or KOH alcoholic solution, uniformly injecting the mixed solution obtained in the step 1a into the NaOH or KOH alcoholic solution through an injector, and curing into uniform spherical particles to obtain Fe coated by chitosan₃O₄Filtering, washing with deionized water and ethanol, drying, and storing in ethanol solution;

step 2: Chitosan/Fe₃O₄Preparation of-Pd/Cu

2a, weighing a proper amount of CuI, adding distilled water and a proper amount of NaI, stirring for dissolving, adding a proper amount of palladium acetate, and stirring uniformly;

2b, coating the chitosan obtained in the step 1b with Fe₃O₄Adding the particles into the solution obtained in step 2a, continuously stirring, heating, concentrating, adsorbing for 1-2 hr, filtering, and drying under nitrogen protection to obtain black particles, i.e. chitosan/Fe₃O₄-a Pd/Cu composite catalyst.

In the step 1a, the molecular weight of the chitosan is 3-20 ten thousand, the deacetylation degree is 70% -95%, and the mass concentration of the dissolved chitosan in the system is 5-20%.

In the step 1a, the pore-foaming agent is selected from urea, polyvinylpyrrolidone or polyethylene glycol, and the amount of the pore-foaming agent is 2-15% of the mass of the chitosan.

In step 1a, the aldehyde is selected from formaldehyde, acetaldehyde, benzaldehyde, glutaraldehyde or salicylaldehyde and the like, and is preferably salicylaldehyde; the concentration of the aldehyde solution is controlled between 5 and 15 percent.

In the step 1a, when the chitosan and the aldehyde are subjected to crosslinking reaction, the crosslinking degree is controlled to be 1-10%, and the crosslinking time is controlled to be 2-8 hours.

In step 1b, the mass concentration of NaOH or KOH alcoholic solution is 5-10%.

In step 2a, the concentration of CuI is kept between 0.01 and 0.2mol/L, preferably between 0.06 and 0.1 mol/L; the molar amount of palladium acetate is 10% -50%, preferably 15% of the CuI.

The chitosan/Fe prepared by the invention₃O₄The loading range of the bimetal in the Pd/Cu composite catalyst is as follows: calculated by CuI, the mass ratio of the CuI to the composite carrier is 0.5-5%, and Cu: pd molar ratio is 10: 1-2: 1.

in the invention, the modification of the chitosan is mainly to generate Schiff base through cross-linking of aldehyde compounds and the chitosan so as to enhance the matching capacity with bivalent palladium and serve as a ligand, and other ligands do not need to be added during the reaction. The metal palladium and copper are loaded on the carrier, so that the recycling and high-efficiency recovery of the catalyst can be realized, the service efficiency of the catalyst is improved, and the service life of the catalyst is prolonged. Magnetic material Fe₃O₄The catalyst is convenient to separate, and the separation efficiency is greatly improved.

The invention relates to a method for catalytic synthesis of p-aminophenylacetylene by using a bimetallic supported composite catalyst, which takes p-aminoiodobenzene and R-based acetylene as raw materials, generates Sonogashira reaction under the action of the composite catalyst to generate 4-R-based ethynylaniline, and then removes the R group to obtain a target product of the p-aminophenylacetylene. The synthetic route is as follows:

the method for catalytically synthesizing p-aminophenylacetylene by using the bimetal loaded composite catalyst comprises the following steps:

step 1: synthesis of 4-R-ethynyl aniline

Dissolving p-aminoiodobenzene and R-acetylene in a solvent in a nitrogen atmosphere, adding a composite catalyst and a proper amount of alkali, and stirring for reaction; after the reaction is finished, filtering the catalyst, adding a proper amount of diethyl ether, and respectively using 1mol/L NH₄Washing with Cl and saturated brine, collecting the organic phase, drying over anhydrous sodium sulfate, and removing the solventPreparing the mixture to obtain a crude product of the 4-R-ethynyl aniline. The catalyst is washed by ethanol and then dried and recovered.

In the step 1, the structural formula of the R-based acetylene is C ≡ C-R, wherein R is trimethylsilyl, triethylsilyl, triisopropylsilyl, tributyltin and the like.

In the step 1, the reaction temperature is 5-60 ℃, preferably 30-40 ℃; the reaction time is from 1 to 30 hours, preferably from 6 to 8 hours.

In the step 1, the solvent is one or a combination of several of dichloromethane, acetonitrile, DMF, pyridine, triethylamine, THF, diethyl ether, methyl tert-butyl ether and the like. The alkali can be inorganic alkali such as sodium carbonate, potassium carbonate, etc., or organic alkali such as pyridine, triethylamine, ethylenediamine, piperidine, etc., and the adding proportion of the alkali is 1-1.5eq of p-aminoiodobenzene.

In the step 1, the catalyst is calculated by uniformly loading palladium and copper, and the catalytic amount of the palladium is kept to be 1-5 mol% of the p-aminoiodobenzene. The molar ratio of the p-aminoiodobenzene to the R-acetylene is controlled to be 1:0.5-2, preferably 1: 1.1.

Step 2: synthesis of p-aminophenylacetylene

And (2) dissolving the 4-R-ethynyl aniline obtained in the step (1) in a solvent, adding an R-removing reagent, stirring at room temperature for reaction, removing the solvent after the reaction is finished, and recrystallizing to obtain a light brown solid product, namely the target product.

In step 2, the reagent for removing R group is usually cesium fluoride, tetrabutylammonium fluoride, cesium carbonate or potassium carbonate, etc., and the amount is 0.5 to 3eq, preferably 1 to 1.5eq, based on the molar amount of 4-R-ethynylaniline.

In step 2, the solvent is selected from methanol, ethanol, acetonitrile, acetone, diethyl ether or THF, etc.

In step 2, the reaction time is controlled to 10 to 200 minutes, preferably 30 to 60 minutes.

In the step 2, the recrystallization solvent is one or a mixture of ethyl acetate, methyl tert-butyl ether, diethyl ether, acetone, petroleum ether and the like.

The invention has the beneficial effects that:

1. the method for synthesizing the p-aminophenylacetylene has the advantages of simple operation, mild condition, safety, controllability and good repeatability.

2. The modified chitosan can be used as a carrier, and can be efficiently chelated with divalent palladium to serve as a ligand. The carrier adopted by the invention loads both the metal catalyst and the ligand, so that the high-efficiency recovery of the metal catalyst and the ligand can be realized, and the use efficiency of the catalyst and the ligand is increased.

3. The invention converts the homogeneous reaction system into the heterogeneous reaction system by loading the catalyst and the ligand, not only solves the problem that the catalyst is easy to agglomerate, but also can realize the high-efficiency separation of the catalyst and the ligand, and the separated catalyst can be reused by simple treatment after the reaction is finished, thereby greatly reducing the production cost.

4. According to the invention, the chitosan is used for coating the magnetic core, so that the mechanical strength of the carrier is improved, and the catalyst can be quickly separated through magnetism. By applying the magnetic separation technology, the fine magnetic particles can be quickly separated, so that the carrier particles can be made into micron-sized or even nano-sized particles, the specific surface area and the loading capacity of the carrier can be greatly increased, and the catalytic efficiency is greatly improved. The maximum adsorption capacity of the carrier is 6-8g/100g (calculated as CuI) when the particle size of the carrier is 0.5-1mm, 10-15g/100g when the particle size of the carrier is reduced to 10-200 μm, and the maximum adsorption capacity is increased when the particle size of the carrier is smaller.

Detailed Description