CN110105547B

CN110105547B - Preparation method of catalyst for silica-supported carbene polymerization reaction

Info

Publication number: CN110105547B
Application number: CN201910424916.2A
Authority: CN
Inventors: 肖龙强; 郭博庚; 侯琳熙
Original assignee: Fuzhou University
Current assignee: Fuzhou University
Priority date: 2019-05-21
Filing date: 2019-05-21
Publication date: 2021-04-27
Anticipated expiration: 2039-05-21
Also published as: CN110105547A

Abstract

The invention provides a preparation method of a catalyst for silica-supported carbene polymerization reaction, belonging to the field of synthesis of high polymer materials, wherein the structural formula of the catalyst is as follows:

the catalyst can be circularly used for carbene polymerization reaction, can maintain high-efficiency catalytic polymerization activity, and can successfully overcome the problems of resource waste and environmental damage of the existing metal catalyst.

Description

Preparation method of catalyst for silica-supported carbene polymerization reaction

Technical Field

The invention belongs to the field of synthesis of high polymer materials, and particularly relates to a silica-supported recyclable catalyst for carbene polymerization reaction and a preparation method thereof, in particular to a recyclable novel catalyst for synthesis of ethyl diazoacetate polymers.

Background

Carbon chain polymers are typically obtained by olefin polymerization from ethylene or derivatives thereof. Although olefin polymerization has been widely used in the fields of plastics, synthetic fibers, synthetic rubbers, etc., and has formed a huge industry, there are some limitations such as the inability to obtain polymers having polar groups per carbon atom in the carbon chain, and the difficulty in controlling the stereochemistry of polyolefins. The carbene polymerization reaction breaks through the conventional limitations and provides a new way for developing carbon chain polymers with unique structures.

Currently, carbene polymerizations are mainly carried out with the aid of metal-based catalysts, such as organoaluminum, organopalladium, organocopper, organorhodium, and the like. While these studies have achieved some encouraging progress and show significant promise, these catalysts are not recyclable and the removal of residual catalyst limits the batch use of transition metal catalysts and can be environmentally damaging. Therefore, the heterogeneous catalyst is obtained by combining the carbene polymerization catalyst with the silica microspheres with sulfydryl by using the existing carbene polymerization catalyst preparation method for reference, and can be efficiently recycled for catalyzing carbene polymerization reaction, so that the resource waste and the damage to the environment are reduced.

Disclosure of Invention

The invention aims to provide a preparation method of a silica-supported catalyst for carbene polymerization reaction, which can relieve resource waste and environmental damage caused by the use of the existing metal catalyst.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation method of a catalyst for silica-supported carbene polymerization reaction comprises the following steps:

(1) adding Boc-L hydroxyproline and triethylamine into a flask filled with a solvent A in sequence, stirring, diluting acryloyl chloride with the solvent A, adding into a mixed solution, stirring at normal temperature for 10-15 h, filtering to remove solids, extracting the filtrate, and drying to obtain a product A, wherein the structural formula is as follows:

；

(2) dissolving the product A in a solvent B, stirring for 5-10 min, adding trifluoroacetic acid, stirring at room temperature for 2-5 h, and recrystallizing to obtain a product B without Boc, wherein the structural formula is as follows:

；

(3) adding the product B and the mercapto silica gel into a solvent C, and carrying out reflux stirring reaction for 10-15 h to obtain a load product C, wherein the structural formula is as follows:

；

(4) adding the product C into a solution in which a (1, 5-cyclooctadiene) chlororhodium (I) dimer is dissolved, and reacting for 3-5 h at normal temperature to obtain the catalyst for carbene polymerization reaction, wherein the structural formula of the catalyst is as follows:

。

in the step (1), the mole ratio of Boc-L hydroxyproline to acryloyl chloride to triethylamine is 1.0:1.1: 2.1-1.0: 1.2: 2.1; the solvent A used is tetrahydrofuran.

The molar ratio of the product A to the trifluoroacetic acid in the step (2) is 1.0: 5.0-1.0: 6.0; the solvent B used was dichloromethane.

The molar ratio of the number of sulfydryl groups on the silica gel to the product B in the step (3) is 1.0: 1.1-1.0: 1.2; the solvent C used was toluene.

The temperature of the reflux stirring reaction in the step (3) is 70-80 ℃.

The molar ratio of the product C to the (1, 5-cyclooctadiene) chlororhodium (I) dimer in the step (4) is 1.0: 1.5-1.0: 2.0; the solvent used in the solution was acetone.

Compared with the prior art, the invention has the following advantages and beneficial effects:

1. the catalyst prepared by the invention belongs to a heterogeneous catalyst, and is convenient to separate.

2. The metal rhodium in the catalyst prepared by the invention is loaded on the silicon dioxide microspheres and can be recycled.

3. The catalyst for carbene polymerization reaction prepared by the invention has the advantages of high catalytic activity and good cyclicity.

Drawings

FIG. 1 is a graph showing the infrared comparison of the catalyst obtained in example 1 with Boc-L hydroxyproline, (1, 5-cyclooctadiene) chlororhodium (I) dimer, and mercaptosilica gel as a starting material.

FIG. 2 is a GPC chart of a product obtained by polymerizing ethyl diazoacetate for 12 h in example 2.

FIG. 3 shows the monomer conversion rate of 5 times of the catalyst cycle-catalyzed ethyl diazoacetate polymerization.

Detailed Description

In order to make the present invention more comprehensible, the technical solutions of the present invention are further described below with reference to specific embodiments, but the present invention is not limited thereto.

Example 1

(1) Adding 21.6 mmol of Boc-L hydroxyproline and 45.4mmol of triethylamine into a flask filled with tetrahydrofuran in sequence, stirring, diluting 23.8 mmol of acryloyl chloride with tetrahydrofuran, adding into a mixed solution, stirring at normal temperature for 10-15 h, filtering to remove solids, drying the filtrate in vacuum, dissolving in 100 mL of deionized water, extracting and washing with 200 mL of dichloromethane for three times, and drying the obtained organic phase in vacuum on sodium sulfate to obtain a product A, wherein the structural formula of the product A is as follows:

；

(2) dissolving 20 mmol of the product A in dichloromethane, stirring for 5-10 min, adding 120 mmol of trifluoroacetic acid, stirring for 2-5 h at room temperature, and recrystallizing to obtain a product B without Boc, wherein the structural formula is as follows:

；

(3) adding 21 mmol of the product B and 4.2 mmol of mercapto silica gel (the content of mercapto in the mercapto silica gel is 1.2 mmol/g) into toluene, and carrying out reflux stirring reaction at 70-80 ℃ for 10-15 h to obtain a load product C, wherein the structural formula is as follows:

；

(4) adding 4mmol of the product C into acetone dissolved with 8 mmol of (1, 5-cyclooctadiene) chlororhodium (I) dimer, and reacting for 3-5 h at normal temperature to obtain the catalyst for carbene polymerization, wherein the structural formula is as follows:

。

FIG. 1 shows the catalyst obtained andinfrared comparison of Boc-L hydroxyproline, (1, 5-cyclooctadiene) chlororhodium (I) dimer, mercaptosilica gel. As can be seen from the figure, Boc-L hydroxyproline is at 1660-1750 cm-¹Carboxyl carbon oxygen double bonds and keto carbon oxygen double bonds exist nearby and still exist in the synthesized catalyst, and the rhodium catalyst is 2900 cm-¹The expansion vibration of saturated hydrocarbon is nearby and is 1465 cm-¹The nearby saturated hydrocarbon bending vibration, and the synthesized catalyst is 2800 cm-¹There is a waveform change in the vicinity, which is caused by the introduction of the rhodium catalyst and is at 1300 cm-¹The absorption enhancement happens nearby due to the conjugation of carbon-nitrogen bonds, thereby proving that the catalyst is successfully synthesized.

Example 2

0.02 mg of the catalyst prepared in example 1 was added to a 25 ml reaction tube, 5 ml of methylene chloride was added, and oxygen was removed by bubbling nitrogen for 5 min. 0.126 g (1 mmol) of ethyl diazoacetate was dissolved in 3 ml of dichloromethane, and the solution was injected into a reaction tube using a needle tube and stirred at room temperature for 12 hours. And after the reaction is finished, centrifugally separating out the solid catalyst, drying and weighing, adding a drop of methanol into supernatant obtained by centrifugation, stirring for 1 min at normal temperature, dropwise adding the obtained solution into 100 ml of methanol for precipitation, centrifugally taking out precipitate, and drying in vacuum to obtain the ethyl diazoacetate polymer.

Example 3

The dried catalyst of example 2 was added to a 25 ml reaction tube, 5 ml of dichloromethane was added, and oxygen was removed by bubbling nitrogen for 5 min. 0.126 g (1 mmol) of ethyl diazoacetate was dissolved in 3 ml of dichloromethane, and the solution was injected into a reaction tube using a needle tube and stirred at room temperature for 12 hours. And (3) after the reaction is finished, centrifugally separating out the solid catalyst, drying and weighing, adding a drop of methanol into the supernatant obtained by centrifugation, stirring at normal temperature for 1 min, dropwise adding the obtained solution into 100 ml of methanol for precipitation, centrifugally taking out the precipitate, and drying in vacuum to obtain the ethyl diazoacetate polymer. The procedure of this example was repeated 3 times, and the monomer conversion of ethyl diazoacetate per time is shown in FIG. 3.

The above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made in accordance with the claims of the present invention should be covered by the present invention.

Claims

1. A preparation method of a catalyst for silica-supported carbene polymerization reaction is characterized by comprising the following steps: the method comprises the following steps:

(1) the method comprises the following steps of dissolving Boc-L hydroxyproline and triethylamine in a solvent A in sequence, adding acryloyl chloride, stirring at normal temperature for 10-15 hours, filtering to remove solids, extracting the filtrate, and drying to obtain a product A, wherein the structural formula of the product A is as follows:

；

；

；

。

2. the method for producing a silica-supported carbene polymerization catalyst according to claim 1, characterized in that: in the step (1), the mole ratio of Boc-L hydroxyproline to acryloyl chloride to triethylamine is 1.0:1.1: 2.1-1.0: 1.2: 2.1;

the solvent A used is tetrahydrofuran.

3. The method for producing a silica-supported carbene polymerization catalyst according to claim 1, characterized in that: the molar ratio of the product A to the trifluoroacetic acid in the step (2) is 1.0: 5.0-1.0: 6.0;

the solvent B used was dichloromethane.

4. The method for producing a silica-supported carbene polymerization catalyst according to claim 1, characterized in that: the molar ratio of the number of sulfydryl groups on the silica gel to the product B in the step (3) is 1.0: 1.1-1.0: 1.2;

the solvent C used was toluene.

5. The method for producing a silica-supported carbene polymerization catalyst according to claim 1, characterized in that: the temperature of the reflux stirring reaction in the step (3) is 70-80 ℃.

6. The method for producing a silica-supported carbene polymerization catalyst according to claim 1, characterized in that: the molar ratio of the product C to the (1, 5-cyclooctadiene) chlororhodium (I) dimer in the step (4) is 1.0: 1.5-1.0: 2.0;

the solvent used in the solution was acetone.

7. The application of the catalyst for carbene polymerization reaction prepared by the preparation method of claim 1 in catalyzing the synthesis of diazoethyl acetate polymer.