1 -pinacolboronate styrene for the preparation of alternating copolymers

Abstract

The application of 1-boronic acid pinacol styrene in preparation of alternating copolymer is proposed, and belongs to the field of polymer synthesis and application. The alternating copolymer is synthesized by using the 1-boronic acid pinacol styrene, so that the type range of reaction substrates can be expanded, the reaction substrates can be extended to acrylate, acrylamide, acrylonitrile, maleic anhydride or maleimide, and a series of poly(1-boronic acid pinacol styrene-alternating-copolymer) can be synthesized, and the problem of limited reaction substrates is overcome. The raw material used in the application is a commercially available compound, the cost is low, the operation is simple and convenient, and the product is free of metal residues.

Description

Technical Field

[0001] This invention belongs to the field of polymer synthesis and application, and particularly relates to the application of 1-boronate pinacol ester styrene in the preparation of alternating copolymers. Background Technology

[0002] Alternating copolymers have attracted widespread attention due to their important applications in the polymer field. Among them, the alternating copolymers of styrene and maleic anhydride are widely used in industry and daily life in molding resins, polymer additives, pigment dispersants, ink modification, powder coatings, leather retanning, floor care products, etc., demonstrating the enormous practical value of these alternating copolymers. Most known synthetic methods are free radical synthesis, with benzoyl peroxide and azobis(isobutyronitrile) being the most commonly used initiators. Copolymerization can be carried out in bulk and in common organic solvents such as tetrahydrofuran, acetone, benzene, carbon tetrachloride, and saturated hydrocarbons. However, under these conditions, styrene can only polymerize with strongly electron-withdrawing monomers such as maleic anhydride or maleimide to obtain alternating copolymers. The substrate range of the reaction is greatly limited. Summary of the Invention

[0003] The purpose of this invention is to propose the application of 1-boronate styrene in the preparation of alternating copolymers. By using 1-boronate styrene to synthesize alternating copolymers, the range of reaction substrates can be expanded to include acrylates, acrylamides, acrylonitriles, maleic anhydrides, or maleimides, etc., and a series of poly(1-boronate styrene-alternating-copolymers) can be synthesized, overcoming the problem of limited reaction substrates.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] The application of 1-boronate styrene in the preparation of alternating copolymers, specifically, 1-boronate styrene is used as a comonomer to prepare alternating copolymers.

[0006] Furthermore, styrene-1-boronate is used as a comonomer to prepare alternating copolymers, the preparation steps of which include:

[0007] Using a free radical initiator, styrene-1-boronate was used as one comonomer, and one of acrylate, acrylamide, acrylonitrile, maleic anhydride, and maleimide was used as another comonomer. The two comonomers were reacted under N2 atmosphere and in an organic solvent to obtain an alternating copolymer poly(styrene-1-boronate-copolymer).

[0008] Furthermore, the reaction equations are as follows:

[0009]

[0010] In Formula I, Ia represents styrene-1-boronate pinacol ester, IIa represents acrylate, and R 1 Representing various alkyl groups, IIIa represents poly(1-boronate styrene-alternating copolymer);

[0011]

[0012] In Formula II, Ia represents 1-boronate styrene, IIb represents acrylamide, and R 2 and R 3 Representing various alkyl groups, IIIb represents poly(1-boronate styrene-alternating copolymer);

[0013]

[0014] In Formula III, Ia represents styrene-1-boronate, IIc represents acrylonitrile, and IIIc represents poly(styrene-1-boronate-alternating copolymer);

[0015]

[0016] In Formula IV, Ia represents styrene-1-boronate, IId represents maleic anhydride, and IIId represents poly(styrene-1-boronate-alternating copolymer);

[0017]

[0018] In formula V, Ia represents styrene-1-boronate pinacol ester, IIe represents maleimide, and R 4 Represents various alkyl groups, and IIIe represents poly(1-boronate styrene-alternating copolymer).

[0019] Furthermore, in formula I, alkyl R 1 It is an alkyl group having 1 to 10 carbon atoms.

[0020] Furthermore, in formula II, alkyl R 2 R 3 It is an alkyl group having 1 to 10 carbon atoms.

[0021] Furthermore, in formula V, alkyl R 4 It is an alkyl group having 1 to 10 carbon atoms.

[0022] Furthermore, azo initiators or organic peroxide initiators are selected as free radical initiators.

[0023] Furthermore, azo initiator is selected as azobisisobutyronitrile, and organic peroxide initiator is selected as benzoyl peroxide.

[0024] Among the free radical initiators used in the method of this invention, azo initiators such as azobisisobutyronitrile are commercially available reagents and do not require special treatment; organic peroxide initiators such as benzoyl peroxide need to be recrystallized and dehydrated before use.

[0025] Furthermore, the amount of free radical initiator used is 1%-5% molar ratio of pinacol 1-borate to styrene.

[0026] Furthermore, the copolymer monomers acrylate, acrylamide, acrylonitrile, maleic anhydride, and maleimide are all commercially available reagents. Among them, acrylate, acrylamide, and acrylonitrile need to be redistilled to remove polymerization inhibitors; maleic anhydride and maleimide need to be recrystallized.

[0027] Furthermore, the copolymer monomers acrylate, acrylamide, acrylonitrile, maleic anhydride, and maleimide are used in a molar ratio of 33% to 100% of 1-boronate styrene.

[0028] Furthermore, the organic solvent may be, but is not limited to, toluene. This organic solvent is a commercially available reagent that needs to be dried with metallic sodium and then distilled under a nitrogen atmosphere before use. The preferred dosage is 100 μL / 0.5 mmol 1-boronate styrene.

[0029] Furthermore, the reaction time is 24-96 h, with the reaction temperature for azobisisobutyronitrile being 65 °C and the reaction temperature for benzoyl peroxide being 70 °C.

[0030] Furthermore, the heating process of the reaction can be carried out using a metal heating module, an oil bath (such as silicone oil, paraffin oil, etc.), or other heating methods.

[0031] Furthermore, after the reaction is completed, the product undergoes post-processing, which includes precipitation or purification using preparative permeation gel chromatography, followed by drying in a vacuum drying oven. The precipitation is only feasible for products IIIc, IIId, and IIIe, and methanol can be used as a poor solvent while dichloromethane is used as a good solvent. The purification using preparative permeation gel chromatography is applicable to all products, and chloroform is used as the eluent during the purification process. The drying in a vacuum drying oven is applicable to all products, and the drying process lasts for at least 24 hours.

[0032] This invention provides a method for preparing alternating copolymers by using styrene-1-boronate pinacol ester as a comonomer, which can undergo free radical copolymerization reactions with acrylates, acrylamide, acrylonitrile, maleic anhydride, and maleimide, respectively. This method has low reaction costs and yields valuable alternating copolymers. Compared with existing technologies, this invention has the following advantages:

[0033] 1. In this invention, 1-boronate pinacol styrene is used as a comonomer, which can broaden the range of substrates, such as acrylates, acrylamide, acrylonitrile, maleic anhydride, maleimide, etc., and can construct a variety of alternating copolymers;

[0034] 2. This invention uses 1-boronate pinacol styrene as a comonomer, which is a commercially available compound that is inexpensive and easy to obtain;

[0035] 3. In this invention, 1-boronate pinacol styrene is used as a comonomer, the reaction conditions do not involve metals, and the product has no metal residues;

[0036] 4. In this invention, 1-boronate pinacol styrene is used as a comonomer, and the reaction conditions are mild and the operation is convenient and simple.

[0037] 5. In this invention, 1-boronate pinacol styrene is used as a comonomer. The copolymer prepared has a higher glass transition temperature, which can supplement the application range of polystyrene. Detailed Implementation

[0038] To make the various technical features, advantages, or effects of the present invention more apparent and understandable, detailed descriptions are provided below in conjunction with embodiments.

[0039] Example 1

[0040] Synthesis of poly(1-pinarate styrene-alternating-n-butyl acrylate)

[0041] Styrene-1-boronate (921 mg, 4.0 mmol, 2.0 equiv), azobisisobutyronitrile (6.56 mg, 0.04 mmol, 0.02 equiv) as initiator, n-butyl acrylate (256 mg, 2.0 mmol, 1.0 equiv), and toluene (400 μL) were added to a 4 mL vial with a polytetrafluoroethylene cap under a nitrogen atmosphere. The reaction system was heated to 65 °C and reacted for 96 hours. The polymerization reaction was quenched at room temperature. The reaction system was diluted with chloroform and purified by preparative permeation gel chromatography. The separated product was dried in a vacuum drying oven to obtain a pure product. The product was a white powder solid with a yield of 68%. The product structure is shown below:

[0042]

[0043] Its NMR data are as follows:

[0044] 1 H NMR (400MHz, CD2Cl2): δ7.52-6.68(m, 5H), 3.56-0.62(m, 26H); 13C NMR (151MHz, CD2Cl2): δ175.9, 143.1, 128.9, 127.3, 125.0, 83.3, 63.7, 43.5, 39.8, 34.5, 30.2, 25.0, 20.2, 13.9.

[0045] Example 2

[0046] Synthesis of poly(1-boronate styrene-alternating-N,N-dimethylacrylamide)

[0047] Styrene-1-boronate (921 mg, 4.0 mmol, 2.0 equiv), azobisisobutyronitrile (6.56 mg, 0.04 mmol, 0.02 equiv), N,N-dimethylacrylamide (198 mg, 2.0 mmol, 1.0 equiv), and toluene (400 μL) were added to a 4 mL vial with a polytetrafluoroethylene cap under a nitrogen atmosphere. The reaction system was heated to 65 °C and reacted for 96 hours. The polymerization reaction was quenched at room temperature. The reaction system was diluted with chloroform and purified by preparative permeation gel chromatography. The separated product was dried in a vacuum drying oven to obtain a pure product. The product was a white powder solid with a yield of 46%. The product structure is shown below:

[0048]

[0049] Its NMR data are as follows:

[0050] 1 H NMR (400MHz, CD2Cl2): δ7.06 (br, 5H), 2.95-0.80 (m, 23H); 13 C NMR (151MHz, CD2Cl2): δ175.3, 144.2, 129.5, 127.4, 125.2, 83.1, 46.5, 36.8, 35.6, 25.6.

[0051] Example 3

[0052] Synthesis of poly(pinarate-1-borate styrene-alternating-acrylonitrile)

[0053] Styrene-1-boronate (921 mg, 4.0 mmol, 2.0 equiv), azobisisobutyronitrile (6.56 mg, 0.04 mmol, 0.02 equiv) as initiator, acrylonitrile (106 mg, 2.0 mmol, 1.0 equiv) and toluene (400 μL) were added to a 4 mL vial with a polytetrafluoroethylene cap under a nitrogen atmosphere. The reaction system was heated to 65 °C and reacted for 96 hours. The polymerization reaction was quenched at room temperature. The reaction system was precipitated with methanol at room temperature. The separated product was dried in a vacuum drying oven to obtain a pure product. The product was a white powdery solid with a yield of 75%. The product structure is shown below:

[0054]

[0055] Its NMR data are as follows:

[0056] 1 H NMR (400MHz, CD2Cl2): δ7.22 (br, 5H), 2.46-1.36 (m, 5H), 1.37-0.92 (m, 12H); 13 CNMR (151MHz, CD2Cl2): δ142.4, 141.8, 128.8, 128.1, 126.9, 123.0, 84.8, 84.6, 43.3, 40.5, 36.7, 34.7, 25.4, 25.1.

[0057] Example 4

[0058] Synthesis of poly(1-boronate styrene-alternating-maleic anhydride)

[0059] Styrene-1-boronate (690 mg, 3.0 mmol, 1.5 equiv), azobisisobutyronitrile (6.56 mg, 0.04 mmol, 0.02 equiv) as initiator, maleic anhydride (196 mg, 2.0 mmol, 1.0 equiv), and toluene (400 μL) were added to a 4 mL vial with a polytetrafluoroethylene cap under a nitrogen atmosphere. The reaction system was heated to 65 °C and reacted for 24 hours. The polymerization reaction was quenched at room temperature. The reaction system was precipitated with methanol at room temperature. The separated product was dried in a vacuum drying oven to obtain a pure product. The product was a white powdery solid with a yield of 68%. The product structure is shown below:

[0060]

[0061] Its NMR data are as follows: 1H NMR (400MHz, CD2Cl2): δ8.28-6.17(m, 5H), 4.01-1.75(m, 4H), 1.19(br, 12H); 13 C NMR (151MHz, CD2Cl2): δ174.07, 172.75, 139.96, 129.86, 128.86, 86.62, 86.39, 84.83, 76.34, 43.69, 38.28, 26.63, 25.89, 25.72, 25.43.

[0062] Example 5

[0063] Synthesis of poly(1-boronate styrene-alternating-N-ethylmaleimide)

[0064] Styrene-1-boronate (690 mg, 3.0 mmol, 1.5 equiv), azobisisobutyronitrile (6.56 mg, 0.04 mmol, 0.02 equiv) as initiator, N-ethylmaleimide (250 mg, 2.0 mmol, 1.0 equiv) and toluene (400 μL) were added to a 4 mL vial with a polytetrafluoroethylene cap under a nitrogen atmosphere. The reaction system was heated to 65 °C and reacted for 48 hours. The polymerization reaction was quenched at room temperature. The reaction system was precipitated with methanol at room temperature. The separated product was dried in a vacuum drying oven to obtain a pure product. The product was a white powdery solid with a yield of 68%. The product structure is shown below:

[0065]

[0066] Its NMR data are as follows:

[0067] 1 H NMR (400MHz, CD2Cl2): δ7.08 (br, 5H), 3.93-0.39 (m, 21H); 13 C NMR (151MHz, CD2Cl2): δ179.2, 143.2, 128.0, 84.2, 83.5, 40.6, 36.7, 34.2, 25.7, 13.3.

[0068] Although the present invention has been disclosed above with reference to embodiments, it is not intended to limit the present invention. Appropriate modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention should be covered within the protection scope of the present invention, which is defined by the claims.

Claims

The application of 1,1-pinarate styrene in the preparation of alternating copolymers, characterized in that, Styrene-1-boronate is used as a comonomer to prepare alternating copolymers. The preparation steps include: Using a free radical initiator, styrene-1-boronate is used as one comonomer, and one of acrylate, acrylamide, acrylonitrile, and maleic anhydride is used as another comonomer. The two comonomers are reacted under N2 atmosphere and in an organic solvent to obtain an alternating copolymer (styrene-1-boronate-alternating copolymer).

2. The application as described in claim 1, characterized in that, The reaction equations are as follows: Formula I In Formula I, Ia represents styrene-1-boronate pinacol ester, IIa represents acrylate, and R 1 Represents various alkyl groups, with IIIa representing poly(1-boronate styrene-alternating copolymer). Formula II In Formula II, Ia represents 1-boronate styrene, IIb represents acrylamide, and R 2 and R 3 Represents various alkyl groups, with IIIb representing poly(1-boronate styrene-alternating copolymer). Formula III In Formula III, Ia represents styrene-1-boronate, IIc represents acrylonitrile, and IIIc represents poly(styrene-1-boronate-alternating copolymer). Formula IV In Formula IV, Ia represents styrene-1-boronate, IId represents maleic anhydride, and IIId represents poly(styrene-1-boronate-alternating copolymer).

3. The application as described in claim 2, characterized in that, In formula I, R 1 It is an alkyl group having 1 to 10 carbon atoms; R in Formula II 2 R 3 It is an alkyl group having 1 to 10 carbon atoms.

4. The application as described in claim 1 or 2, characterized in that, The free radical initiator is an azo initiator or an organic peroxide initiator; the azo initiator is azobisisobutyronitrile, and the organic peroxide initiator is benzoyl peroxide; the amount of free radical initiator is 1%-5% molar ratio of pinacol 1-borate to styrene.

5. The application as described in claim 1 or 2, characterized in that, Acrylic esters, acrylamide, and acrylonitrile are used as comonomers after being redistilled to remove polymerization inhibitors; maleic anhydride is used as a comonomer after recrystallization.

6. The application as described in claim 1 or 2, characterized in that, The copolymer monomers acrylate, acrylamide, acrylonitrile, and maleic anhydride are used in a molar ratio of 33% to 100% of 1-boronate styrene.

7. The application as described in claim 1 or 2, characterized in that, Toluene was chosen as the organic solvent. After being dried with metallic sodium, it was distilled under a nitrogen atmosphere and used at a rate of 100 μL / 0.5 mmol 1-boronate styrene.

8. The application as described in claim 1 or 2, characterized in that, The reaction time is 24-96 hours.

9. The application as described in claim 1 or 2, characterized in that, After the reaction is complete, the product is post-processed, which includes: firstly, precipitation, or purification using preparative permeation gel chromatography; and then drying using a vacuum drying oven.

Images