CN109161028B - A kind of preparation method of photodegradable two-dimensional polymer with cucurbituril as structural unit - Google Patents

Abstract

The invention discloses a preparation method of a photodegradable two-dimensional macromolecule with cucurbituril as a structural unit. The structural unit of the material is cucurbituril, and the photosensitive compound spiropyran is covalently grafted on its waist. Under UV light irradiation, the merocyanine structure formed by the ring-opening of spiropyran can undergo a 2:1 coordination reaction with calcium and magnesium divalent ions, and then link the cucurbituril into a two-dimensional polymer with a monomolecular thickness along the direction measurement. flat. Under the irradiation of visible light, the merocyanine structure will close the ring to form a spiropyran, releasing calcium and magnesium divalent ions, resulting in the controllable photodegradation of the two-dimensional polymer plane. The above degradation reaction does not require the participation of high temperature, high pressure or other chemical reagents, is environmentally friendly and has spatial and temporal accuracy, which provides an important reference for solving the problem of environmental pollution caused by the accumulation of two-dimensional polymers.

Description

Preparation of a photodegradable two-dimensional polymer with cucurbituril as a structural unit method

technical field

The invention relates to a preparation method of a photodegradable two-dimensional macromolecule with cucurbituril as a structural unit, and belongs to the field of sustainable chemical industry.

Background technique

Since its advent in the early 1930s, synthetic linear or disordered cross-linked polymers have been widely used in science and technology, national defense construction and All areas of the national economy have become indispensable and important materials for modern social life. In recent years, the discovery and prosperity of graphene has stimulated interest in designing and synthesizing novel 2D materials at the atomic or molecular level. To this end, people have boldly extended the traditional Staudinger polymerization theory, extending the connection direction between monomers from a simple one-dimensional to two-dimensional, thus developing a series of two-dimensional repeating units and internal periodic structures. Dimensional polymers have shown attractive application prospects in the fields of selective separation, sensors, and energy storage.

However, as with the advent of traditional synthetic polymers, people often only focus on the application properties of materials when designing two-dimensional polymers, while ignoring another basic requirement of modern society for new materials, namely degradability. In fact, the global annual production of polymer plastic waste has reached 275 million tons, and most of them have high recycling costs and are difficult to degrade in a short period of time, which has brought huge pressure on the environment and ecology. So far, 2D polymers designed by predecessors are also difficult to degrade under mild or no secondary pollution conditions; when they are applied on a large scale, this will lead to massive accumulation of 2D polymers, creating an environment similar to traditional polymers Pollution.

SUMMARY OF THE INVENTION

The purpose of this invention is to overcome the shortcomings and deficiencies existing in the prior art, and provide a kind of preparation method of photodegradable two-dimensional macromolecule with cucurbituril as structural unit, it is characterized in that the processing steps and conditions of this method are as follows , the parts of the following materials are all parts by weight:

(1) Preparation of spiropyran with carboxyl group:

(1.1) Dissolve 3-5 parts of indoline and 4-10 parts of quaternary ammonium reagent with carboxyl group in 20-40 parts of solvent, react under nitrogen protection at 90-110 ° C for 3-5 h, the obtained product is dissolved In 100-250 parts of distilled water and repeated extraction with equal volume of chloroform, the obtained aqueous solution is dried to constant weight to obtain indoline with carboxyl group;

(1.2) Dissolve the above 1-5 parts of indoline with carboxyl group and 1-2 parts of salicylaldehyde in 20-50 parts of absolute ethanol, add 0.5-0.8 parts of catalyst, and react at 60-90 ℃ under nitrogen protection After 3-5 h, the obtained product was filtered at -20°C, washed with ice ethanol, dried to constant weight, and then the spiropyran with carboxyl group was obtained;

(2) Preparation of hydroxylated cucurbituril: Dissolve 1-5 parts of cucurbituril and 3-15 parts of persulfate in 50-100 parts of distilled water, react under nitrogen protection at 60-90°C for 6-8 h, and the reaction is over After cooling and filtering, adding 50-100 parts of acetone to the liquid to obtain a precipitate, washing with acetone and drying to constant weight to obtain hydroxylated cucurbituril;

(3) Preparation of spiropyran-modified cucurbituril: 5-10 parts of hydroxylated cucurbituril and 2-8 parts of spiropyran with carboxyl groups are dissolved in 20-50 parts of solvent, 1-3 parts of catalyst are added, and 1-3 parts of catalyst are added. The reaction is carried out at room temperature for 36-48 h, and after the reaction is completed, it is cooled and filtered, and 40-80 parts of distilled water are added to the liquid to obtain a precipitate, which is washed with acetone and dried to constant weight to obtain the spiropyran-modified cucurbituril;

(4) Preparation of photodegradable two-dimensional polymers: 0.5-4 parts of the spiropyran-modified cucurbituril prepared above and an equimolar divalent metal salt were added to 100 parts of dimethyl sulfoxide, and UV light ( Wavelength 315-400 nm) irradiation for 0.5-1 h.

In the above method, the indoline in step (1.1) is one or more of 3-methylindoline, 2,5-dimethylindoline and 2,3,3-trimethylindoline kind.

In the above method, the quaternization reagent with carboxyl group described in step (1.1) is one or more of 2-iodoacetic acid, 3-iodopropionic acid and 4-iodobutyric acid.

In the above method, the solvent described in step (1.1) and step (3) is one or more of toluene, N,N -dimethylformamide, N,N -dimethylacetamide, and tetrahydrofuran.

In the above method, the salicylaldehyde described in step (1.2) is 5-nitrosalicylaldehyde, 4-diethylaminosalicylaldehyde, 5-chloromethylsalicylaldehyde, 3-chloromethyl-5-nitro One or more of salicylaldehyde.

In the above method, the catalyst described in step (1.2) is pyridine, 4-nitropyridine, 1-carboxypyridine, 2-aminomethylpyridine, 4-piperidinylpyridine, piperidine, 1-carboxypiperidine, 4-nitropyridine One or more of the group consisting of piperidine, 2-aminomethyl piperidine and 4-aminomethyl piperidine.

In the above method, the cucurbituril described in step (2) is one or more of cucurbit[5]uril, cucurbit[6]uril, cucurbit[7]uril, and cucurbit[8]uril.

In the above method, the persulfate in step (2) is one or more of potassium persulfate, ammonium persulfate and sodium persulfate.

In the above method, the catalyst described in step (3) is dicyclohexylcarbodiimide, diisopropylcarbodiimide, 1- ( 3 -dimethylaminopropyl) -3 -ethylcarbodiimide hydrochloride one or more of the salts.

In the above method, the divalent metal salt in step (4) is one or more of magnesium chloride and calcium chloride.

Compared with the prior art, the present invention has the following positive effects:

1. The spiropyran branched on the waist of cucurbituril will open the ring to form a merocyanine structure under the irradiation of ultraviolet light (wavelength 315-400 nm), and the phenolic anion contained can form a 2:1 coordination with calcium and magnesium divalent ions. site reaction, and then the cucurbituril monomers are connected laterally into a two-dimensional polymer plane.

2. The formation of the above-mentioned two-dimensional polymers is carried out in solution without any template or support material.

3. When 2:1 coordination reaction occurs between phenolic oxygen anion and divalent ions such as calcium and magnesium, the cyanine structure at the waist of cucurbituril is positively charged. Due to the repulsion of charges, the stacking between two-dimensional polymer planes will be inhibited , the product has a monomolecular thickness.

4. In the above-mentioned two-dimensional polymer plane, the cavity of cucurbituril and the host-guest reaction ability are preserved, which lays a foundation for the application of the plane in selective separation, and also creates conditions for its surface functionalization.

5. Under the irradiation of visible light, the merocyanine structure will spontaneously close the ring to form a spiropyran, releasing calcium and magnesium divalent ions, leading to the degradation of the two-dimensional polymer plane. This process does not require high temperature, high pressure or other chemical reagents (no two). Sub-pollution) participation, environment-friendly and with spatial and temporal precision.

Description of drawings

Fig. 1 is the preparation route of the spiropyran modified cucurbituril involved in the present invention.

FIG. 2 is a schematic diagram of the principle of two-dimensional polymer formation and photodegradation involved in the present invention.

Detailed ways

The present invention will be specifically described below through examples, which are only used to further illustrate the present invention, and should not be construed as limiting the scope of protection of the present invention. Technical engineers in this field can make some non-essential improvements and Adjustment.

Example 1:

(1) Preparation of indoline with carboxyl group: 3 parts of 3-methylindoline and 4 parts of 3-iodopropionic acid were dissolved in 20 parts of toluene, reacted at 90 °C for 3 h under nitrogen protection, and the obtained product was dissolved in Repeated extraction with equal volume of chloroform in 100 parts of distilled water. The obtained aqueous solution is dried to constant weight to obtain indoline with carboxyl group;

(2) Preparation of spiropyran with carboxyl group: Dissolve 1 part of indoline with carboxyl group and 1 part of 5-nitrosalicylaldehyde in 20 parts of absolute ethanol, add 0.5 part of hexahydropyridine, at 60 ° C The reaction was carried out under nitrogen protection for 3 h, and the obtained product was filtered at -20°C, washed with ice ethanol, dried to constant weight, and then the spiropyran with carboxyl group was obtained;

(3) Preparation of hydroxy-modified cucurbituril: Dissolve 1 part of cucurbit[5]uril and 3 parts of potassium persulfate in 50 parts of distilled water, react under nitrogen protection at 60 °C for 6 h, after the reaction, cool and filter, add to the liquid 50 parts of acetone were collected and precipitated, washed with acetone and dried to constant weight to obtain hydroxyl-modified cucurbit[5]uril;

(4) Preparation of spiropyran-modified cucurbituril: 5 parts of hydroxyl-modified cucurbit[5]uril and 2 parts of carboxyl-modified spiropyran were dissolved in 20 parts of dimethyl sulfoxide, and 1 part of dicyclohexyl was added. Carbodiimide, reacted at room temperature for 36 h, cooled and filtered after the reaction, added 40 parts of distilled water to the liquid to obtain the product, washed with acetone and dried to constant weight to obtain spiropyran-modified cucurbit[5]uril;

(5) Preparation of two-dimensional polymers: 1 part of spiropyran-modified cucurbit[5]uril and equimolar calcium chloride were added to 100 parts of dimethyl sulfoxide, and irradiated with ultraviolet light (wavelength 360 nm) for 0.5 h.

The two-dimensional polymer prepared by the above method is measured as the single-molecule thickness by atomic force microscope. After 1 h of visible light irradiation, transmission electron microscopy and dynamic light scattering experiments showed that the two-dimensional polymers could be rapidly degraded into cucurbit[5]urea and its oligomers.

Example 2:

(1) Preparation of indoline with carboxyl group: Dissolve 5 parts of 2,5-dimethylindoline and 10 parts of 2-iodoacetic acid in 40 parts of N,N-dimethylformamide, under nitrogen at 110°C The reaction was carried out under protection for 5 h, and the obtained product was dissolved in 250 parts of distilled water and repeatedly extracted with an equal volume of chloroform. The obtained aqueous solution is dried to constant weight to obtain indoline with carboxyl group;

(2) Preparation of spiropyran with carboxyl group: Dissolve 5 parts of carboxyindoline and 2 parts of 5-chloromethyl salicylaldehyde in 50 parts of absolute ethanol, add 0.8 part of 4-nitropyridine, The reaction was carried out under nitrogen protection at 90 °C for 5 h, and the obtained product was filtered at -20 °C, washed with ice ethanol, dried to constant weight, and then the spiropyran with carboxyl group was obtained;

(3) Preparation of hydroxy-modified cucurbituril: Dissolve 5 parts of cucurbit[6]uril and 15 parts of ammonium persulfate in 100 parts of distilled water, react at 90 °C for 8 h under nitrogen protection, cool and filter after the reaction, and add to the liquid 100 parts of acetone were collected and precipitated, washed with acetone and dried to constant weight to obtain hydroxyl-modified cucurbit[6]uril;

(4) Preparation of spiropyran-modified cucurbituril: Dissolve 10 parts of hydroxyl-modified cucurbit[6]uril and 8 parts of carboxyl-modified spiropyran in 50 parts of toluene, and add 3 parts of 1-(3-dimethicone) Methylaminopropyl)-3-ethylcarbodiimide, reacted at room temperature for 48h, cooled and filtered after the reaction, added 80 parts of distilled water to the liquid to obtain the product, washed with acetone and dried to constant weight to obtain spiropyran Modified cucurbit[6]urea;

(5) Preparation of two-dimensional polymers: 4 parts of spiropyran-modified cucurbit[6]uril and equimolar magnesium chloride were added to 100 parts of dimethyl sulfoxide, and irradiated with ultraviolet light (wavelength 360 nm) for 0.5 h.

The two-dimensional polymer prepared by the above method is measured as the single-molecule thickness by atomic force microscope. After 1 h of visible light irradiation, transmission electron microscopy and dynamic light scattering experiments showed that the two-dimensional polymer could be rapidly degraded into cucurbit[6]urea and its oligomers.

Example 3:

(1) Preparation of indoline with carboxyl group: 4 parts of 2,3,3-trimethylindoline and 8 parts of 4-iodobutyric acid were dissolved in 30 parts of toluene and reacted at 100 °C for 4 h under nitrogen protection , the obtained product was dissolved in 150 parts of distilled water and repeatedly extracted with an equal volume of chloroform. The obtained aqueous solution is dried to constant weight to obtain indoline with carboxyl group;

(2) Preparation of spiropyran with carboxyl group: Dissolve 3 indoline with carboxyl group and 1.5 parts of 3-chloromethyl-5-nitrosalicylaldehyde in 30 parts of absolute ethanol, add 0.5 part of 4- Piperidinylpyridine was reacted under nitrogen protection at 80°C for 4 h, the obtained product was filtered at -20°C, washed with ice ethanol, dried to constant weight, and then spiropyran with carboxyl group was obtained;

(3) Preparation of hydroxy-modified cucurbituril: Dissolve 3 parts of cucurbit[7]uril and 12 parts of sodium persulfate in 75 parts of distilled water, react under nitrogen protection at 75°C for 7 h, cool and filter after the reaction, add to the liquid 70 parts of acetone were collected and precipitated, washed with acetone and dried to constant weight to obtain hydroxyl-modified cucurbit[7]uril;

(4) Preparation of spiropyran-modified cucurbituril: 7 parts of hydroxyl-modified cucurbit[7]uril and 5 parts of carboxyl-modified spiropyran were dissolved in 40 parts of dimethyl sulfoxide, and 2 parts of dicyclohexyl were added. Carbodiimide, reacted at room temperature for 40 h, cooled and filtered after the reaction, added 60 parts of distilled water to the liquid to obtain the product, washed with acetone and dried to constant weight to obtain spiropyran-modified cucurbit[7]uril;

(5) Preparation of two-dimensional polymers: 2 parts of spiropyran-modified cucurbit[7]uril and equimolar calcium chloride were added to 100 parts of dimethyl sulfoxide, and UV light (wavelength 360 nm) was irradiated for 0.5 h.

The two-dimensional polymer prepared by the above method is measured as the single-molecule thickness by atomic force microscope. After 1 h of visible light irradiation, transmission electron microscopy and dynamic light scattering experiments showed that the two-dimensional polymers could be rapidly degraded into cucurbit[7]urea and its oligomers.

Claims (9)

1. a preparation method of the photodegradable two-dimensional macromolecule taking cucurbituril as structural unit is characterized in that the processing steps and conditions of the method are as follows, and the following parts of materials used are parts by weight: (1) preparation of spiropyran with carboxyl group: (1.1) Dissolve 3-5 parts of indoline and 4-10 parts of quaternary ammonium reagent with carboxyl group in 20-40 parts of solvent, react at 90-110 ℃ under nitrogen protection for 3-5 h, and the obtained product is dissolved in 100-250 parts of distilled water and repeated extraction with equal volume of chloroform, the obtained aqueous solution is dried to constant weight to obtain indoline with carboxyl group; (1.2) Dissolve the above 1-5 parts of indoline with carboxyl group and 1-2 parts of salicylaldehyde in 20-50 parts of absolute ethanol, add 0.5-0.8 parts of catalyst, and react at 60-90 ° C under nitrogen protection After 3-5h, the obtained product was filtered at -20°C, washed with ice ethanol, dried to constant weight, and then the spiropyran with carboxyl group was obtained; (2) Preparation of hydroxylated cucurbituril: Dissolve 1-5 parts of cucurbituril and 3-15 parts of persulfate in 50-100 parts of distilled water, react under nitrogen protection at 60-90° C. for 6-8h, after the reaction finishes Cool and filter, add 50-100 parts of acetone to the liquid to obtain precipitation, wash with acetone and dry to constant weight to obtain hydroxylated cucurbituril; (3) preparation of spiropyran-modified cucurbituril: take 5-10 parts of hydroxylated cucurbituril and 2-8 parts of spiropyran with carboxyl group to dissolve in 20-50 parts of solvent, add 1-3 parts of catalyst, in The reaction is carried out at room temperature for 36-48 h, and after the reaction is completed, it is cooled and filtered, and 40-80 parts of distilled water is added to the liquid to obtain a precipitate, which is washed with acetone and dried to constant weight to obtain the spiropyran-modified cucurbituril; (4) Preparation of photodegradable two-dimensional polymer: add 0.5-4 parts of spiropyran-modified cucurbituril obtained above and equimolar magnesium chloride or calcium chloride into 100 parts of dimethyl sulfoxide, and use the wavelength of 315-400nm UV light irradiation for 0.5-1h. 2. a kind of preparation method of the photodegradable two-dimensional macromolecule taking cucurbituril as structural unit according to claim 1, is characterized in that the described indoline of step (1.1) is 3-methyl indoline , one or more of 2,5-dimethylindoline and 2,3,3-trimethylindoline. 3. the preparation method of a kind of photodegradable two-dimensional macromolecule with cucurbituril as structural unit according to claim 1, it is characterized in that the quaternization reagent with carboxyl group described in step (1.1) is 2-iodine One or more of acetic acid, 3-iodopropionic acid and 4-iodobutyric acid. 4. the preparation method of a kind of photodegradable two-dimensional macromolecule with cucurbituril as structural unit according to claim 1, is characterized in that the solvent described in step (1.1) and step (3) is toluene, N, One or more of N-dimethylformamide, N,N-dimethylacetamide and tetrahydrofuran. 5. the preparation method of a kind of photodegradable two-dimensional macromolecule taking cucurbituril as structural unit according to claim 1, is characterized in that the salicylaldehyde described in step (1.2) is 5-nitrosalicylaldehyde , one or more of 4-diethylaminosalicylaldehyde, 5-chloromethylsalicylaldehyde and 3-chloromethyl-5-nitrosalicylaldehyde. 6. the preparation method of a kind of photodegradable two-dimensional macromolecule with cucurbituril as structural unit according to claim 1, is characterized in that the catalyst described in step (1.2) is pyridine, 4-nitropyridine, 1 -Carboxypyridine, 2-aminomethylpyridine, 4-piperidinylpyridine, piperidine, 1-carboxypiperidine, 4-nitropiperidine, 2-aminomethylpiperidine, 4-aminomethylpiperidine one or more of. 7. the preparation method of a kind of photodegradable two-dimensional macromolecule with cucurbituril as structural unit according to claim 1, it is characterized in that the cucurbituril described in step (2) is cucurbit[5]uril, cucurbit[5] 6] One or more of urea, cucurbit[7]urea, and cucurbit[8]urea. 8. the preparation method of a kind of photodegradable two-dimensional macromolecule with cucurbituril as structural unit according to claim 1, is characterized in that the described persulfate of step (2) is potassium persulfate, ammonium persulfate , one or more of sodium persulfate. 9. the preparation method of a kind of photodegradable two-dimensional macromolecule with cucurbituril as structural unit according to claim 1, is characterized in that the catalyst described in step (3) is dicyclohexylcarbodiimide, dicyclohexylcarbodiimide, dicyclohexylcarbodiimide, dicyclohexylcarbodiimide, dicyclohexylcarbodiimide One or more of isopropylcarbodiimide and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride.

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