阅读说明：本技术 联萘酚类衍生物在活性自由基光聚合反应方面的应用 (Application of binaphthol derivative in active free radical photopolymerization ) 是由 廖赛虎 马强 于 2019-12-11 设计创作，主要内容包括：联萘酚类衍生物在活性自由基光聚合反应方面的应用。本发明涉及有机光催化剂催化可控活性自由基聚合领域,具体涉及1,1’-联-2,2’-萘酚类衍生物作为有机光催化剂,在可见光下发生活性可控自由基光聚合的有机催化体系。本发明使用BINOL类聚合物作为有机光氧化还原催化剂,可以实现休眠种和活性链之间的快速可逆平衡,使得聚合反应具有可控性,可以制备得到分子量可控,低多分散性的均聚物和嵌段共聚物的同时,也为BINOL类有机聚合物提供在有机光催化活性自由基聚合上的全新应用方法；本发明所涉及的有机光催化体系具有高效率,低成本,易操作,制备的聚合物具有分子量可控,多分散性窄特点,符合环境友好型绿色生产的生产理念。(The application of the binaphthol derivative in the aspect of active free radical photopolymerization reaction. The invention relates to the field of organic photocatalyst catalytic controllable active radical polymerization, in particular to an organic catalytic system in which 1,1 '-bi-2, 2' -naphthol derivatives are used as an organic photocatalyst and active controllable radical photopolymerization is carried out under visible light. The BINOL polymer is used as an organic light oxidation-reduction catalyst, so that the rapid reversible balance between a dormant species and an active chain can be realized, the polymerization reaction has controllability, and a brand new application method on organic light catalytic activity free radical polymerization is provided for the BINOL organic polymer while the homopolymer and the block copolymer with controllable molecular weight and low polydispersity can be prepared; the organic photocatalytic system has the advantages of high efficiency, low cost and easy operation, and the prepared polymer has the characteristics of controllable molecular weight and narrow polydispersity and conforms to the production concept of environment-friendly green production.)

1.1,1 '-bi-2, 2' -naphthol derivative as photosensitizer or photocatalyst in the field of active free radical photopolymerization.

The application of 1,1 '-bi-2, 2' -naphthol derivative as photosensitizer or photocatalyst in the photo-initiated homopolymerization or block copolymerization of methacrylate monomer with active free radical.

3. Use according to claim 2, characterized in that: the 1,1 '-bi-2, 2' -naphthol derivative has the following general structure:

in the formula I, R1 and R2 are both selected from hydrogen, alkyl or aryl.

4. Use according to claim 3, characterized in that: in the formula I, R1 and R2 are both selected from one of methyl, ethyl, butyl, phenyl, 4-fluorophenyl, 3, 5-difluorophenyl, 2,4, 6-trifluorophenyl, pentafluorophenyl, 4-trifluoromethylphenyl, 3, 5-bis (trifluoromethyl) phenyl, 4-cyano-substituted phenyl, 4-nitro-substituted phenyl, 1-naphthyl, 2-naphthyl, anthracenyl, pyrenyl, pyridyl, substituted pyridyl, thienyl and substituted thienyl.

5. The active free radical photopolymerization organic catalytic system comprises at least one monomer, an organic photocatalyst, an initiator and an initiation light source, and is characterized in that: the organic photocatalyst is a 1,1 '-bi-2, 2' -naphthol derivative and has the following general structure:

in the formula I, R1 and R2 are both selected from hydrogen, alkyl or aryl.

6. The active radical photopolymerization organocatalyst system as claimed in claim 5, wherein: in the formula I, R1 and R2 are both selected from one of methyl, ethyl, butyl, phenyl, 4-fluorophenyl, 3, 5-difluorophenyl, 2,4, 6-trifluorophenyl, pentafluorophenyl, 4-trifluoromethylphenyl, 3, 5-bis (trifluoromethyl) phenyl, 4-cyano-substituted phenyl, 4-nitro-substituted phenyl, 1-naphthyl, 2-naphthyl, anthracenyl, pyrenyl, pyridyl, substituted pyridyl, thienyl and substituted thienyl.

7. The active radical photopolymerization organocatalyst system as claimed in claim 5, wherein: the initiator is an organic halide.

8. The active radical photopolymerization organocatalyst system as claimed in claim 5, wherein: the monomer at least comprises methacrylate monomers.

9. The active radical photopolymerization organocatalyst system as claimed in claim 5, wherein: the molar ratio of the monomer to the initiator is 10: 1-10000: 1, and the molar ratio of the monomer to the organic photocatalyst is as follows: 1000:1-1000000:1.

10. The active radical photopolymerization organocatalyst system as claimed in claim 9, wherein: the reaction temperature is-20 ℃ to 50 ℃; the reaction time is 2-72 h.

11. The active radical photopolymerization organocatalyst system as claimed in claim 5, wherein: the light source is visible light or near infrared light, and the wavelength is not less than 300 nm.

12. The active radical photopolymerization organocatalyst system as claimed in claim 5, wherein: the reaction system also comprises a solvent, wherein the solvent is selected from one or more of N, N-dimethylformamide, acetonitrile, N-Dimethylacetamide (DMA), toluene, dichloromethane, dimethyl sulfoxide and water.

Technical Field

The invention relates to the field of organic photocatalyst catalytic controllable active radical polymerization, in particular to an organic catalytic system for carrying out active controllable free radical photopolymerization on a methacrylate monomer by taking 1,1 '-bi-2, 2' -naphthol (BINOL) derivatives as an organic photocatalyst under visible light.

Background

Since Szwarc et al suggested the concept of living polymerization in 1956, living polymerization became the most effective method for synthesizing polymers, since it could actually achieve precise control of molecular weight and molecular structure by precisely designing the molecules of the polymer to prepare polymers with specific structures and properties. The activity-controlled/living radial polymerization (CRP) has the characteristics of relatively mild reaction conditions, wide applicable monomer range, simple operation, low industrial cost, wide application range of products and the like, and has the advantage of unique processing technology. In living radical polymerization, compounds such as catalysts or chain transfer agents, which are specific to the living radical polymerization, play a role in the polymerization process, so that the molecular weight of the polymer is increased along with the continuous increase of the monomer conversion rate, and a narrow molecular weight distribution is maintained. Currently, most living radical polymerization reactions are thermal polymerization, i.e., both chain initiation and chain propagation reactions are achieved by thermochemical reaction processes in the polymerization system.

Photopolymerization has been receiving much attention in recent years as a new radical polymerization method. Compared with thermal initiation polymerization reaction, the photopolymerization reaction can be carried out at normal temperature or even low temperature, the operation is simple, the reaction is stable, the polymerization can be quickly started and stopped through the on/off of the light source, and the polymerization reaction can be accurately controlled in time and space scale. The mechanism of the organic photocatalyst for regulating and controlling the free radical polymerization reaction is as follows: the organic photocatalyst is excited after absorbing photons and has stronger reducibility, can transfer an electron to an initiator and lead the initiator to crack out an alkyl radical to initiate polymerization, and the catalyst has stronger oxidizability after losing an electron and can extract an electron from a halide ion or a related active species to convert an active lengthening chain into a dormant state, so that the circulation and balance of activation and deactivation are realized through a photooxidation-reduction process.

The introduction of the organic photocatalyst not only enables the traditional active radical polymerization to be carried out at normal temperature or low temperature, but also overcomes the adverse effect of the traditional metal catalyst catalytic system on the generated polymer, and provides more possibility for the application of the polymer in the industries of food, biomedicine, microelectronics and the like.

For example, the chinese patent with the publication number CN106674394B discloses an initiation system for active radical photopolymerization of methacrylate monomers, which is composed of an organic halide initiator, an aromatic tertiary amine reducing agent and a benzaldehyde photocatalyst with a substituent group. The system can initiate the living radical polymerization of methacrylate monomers at room temperature by taking visible light as a light source. However, the catalytic efficiency of the system is low, long-time illumination is needed to reach a certain conversion rate, an electron-donating amine system also causes increase of polymerization side reaction, the control on the molecular weight of a polymer is weakened, the theoretical molecular weight and the actual molecular weight have large deviation, the increase of the molecular weight in the polymerization process does not show good linear trend, and the control on the polydispersity is also poor (PDI is more than 1.40). The catalyst dosage is large, 5-80% of the monomer is generally needed, and cannot be reduced to one thousandth (1%) or less.

Disclosure of Invention

The invention aims to provide a catalytic system which takes BINOL compounds as a novel photopolymerization catalyst, and provides a high-efficiency, low-cost and easy-to-operate active free radical polymerization method while realizing organic photocatalytic initiation of active free radical photopolymerization of methacrylate monomers; the photocatalyst without metal elements is used for synthesis, and meets the requirement of environment-friendly green production.

The technical scheme of the invention is as follows:

the 1,1 '-bi-2, 2' -naphthol derivative is used as an organic photocatalyst in the aspect of active free radical photopolymerization.

Preferably, the 1,1 '-bi-2, 2' -naphthol derivative is used as a photosensitizer or a photocatalyst in the aspect of the active free radical photoinitiation homopolymerization or block copolymerization of methacrylate monomers.

Preferably, the 1,1 '-bi-2, 2' -naphthol derivative has the following general structure:

in the formula I, R1 and R2 are both selected from hydrogen, alkyl or aryl.

Preferably, in formula I, R1 and R2 are both selected from one of methyl, ethyl, butyl, phenyl, 4-fluorophenyl, 3, 5-difluorophenyl, 2,4, 6-trifluorophenyl, pentafluorophenyl, 4-trifluoromethylphenyl, 3, 5-bis (trifluoromethyl) phenyl, 4-cyano substituted phenyl, 4-nitro substituted phenyl, 1-naphthyl, 2-naphthyl, anthracenyl, pyrenyl, pyridyl, substituted pyridyl, thienyl and substituted thienyl.

Another object of the present invention is to provide a living radical photopolymerization organic catalytic system.

The active free radical photopolymerization organic catalytic system comprises at least one monomer, an organic photocatalyst, an initiator and an initiation light source, wherein the organic photocatalyst is a 1,1 '-bi-2, 2' -naphthol derivative and has the following general structure:

in the formula I, R1 and R2 are both selected from hydrogen, alkyl or aryl.

Preferably, in formula I, R1 and R2 are both selected from one of methyl, ethyl, butyl, phenyl, 4-fluorophenyl, 3, 5-difluorophenyl, 2,4, 6-trifluorophenyl, pentafluorophenyl, 4-trifluoromethylphenyl, 3, 5-bis (trifluoromethyl) phenyl, 4-cyano substituted phenyl, 4-nitro substituted phenyl, 1-naphthyl, 2-naphthyl, anthracenyl, pyrenyl, pyridyl, substituted pyridyl, thienyl and substituted thienyl.

Preferably, the initiator is an organic halide.

Preferably, the monomer includes at least a methacrylate-based monomer.

Preferably, the molar ratio of the monomer to the initiator is 10: 1-10000: 1, and the molar ratio of the monomer to the organic photocatalyst is: 1000:1-1000000:1.

Preferably, the reaction temperature is-20 ℃ to 50 ℃; the reaction time is 2-72 h.

Preferably, the light source is visible light or near infrared light, and the wavelength is not less than 300 nm.

Preferably, the reaction system further comprises a solvent selected from one or more of N, N-dimethylformamide, acetonitrile, N-Dimethylacetamide (DMA), toluene, dichloromethane, dimethylsulfoxide and water.

The method comprises the steps of sequentially adding a methacrylate monomer, an initiator, a photocatalyst and a solvent into a reaction container, filling inert gas for atmosphere protection, fully stirring the mixture at a specific temperature, irradiating by a light source, and then carrying out controllable active radical polymerization at a proper reaction time and reaction temperature. Meanwhile, a small amount of the reaction mixture was withdrawn at the same time intervals and added to deuterated chloroform containing BHT (e.g., 250 ppm) to terminate the polymerization, and after the conversion was monitored by nuclear magnetism and reached a predetermined conversion, the remaining reaction solution was settled in a rapidly stirred poor solvent such as methanol to obtain the final polymerization product.

According to the technical scheme, the controllable active free radical photopolymerization can be carried out: the polymerization product with a certain molecular weight can be prepared and obtained as the macromolecular initiator by feeding according to a certain monomer/initiator ratio, and the macromolecular initiator can be separated or not separated through sedimentation; then adding a certain amount of the same monomer and a certain amount of solvent to carry out photopolymerization again to carry out chain extension reaction to obtain a chain-extended polymer; if a certain amount of another monomer and solvent are added for photopolymerization again, block polymers are obtained, and repeating the steps in sequence, a multi-block polymer can be obtained.

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

the BINOL polymer is used as an organic light oxidation-reduction catalyst, so that the rapid reversible balance between a dormant species and an active chain can be realized, the polymerization reaction has controllability, and a brand new application method on organic light catalytic activity free radical polymerization is provided for the BINOL organic polymer while the homopolymer and the block copolymer with controllable molecular weight and low polydispersity can be prepared; the organic photocatalytic system has the advantages of high efficiency, low cost and easy operation, and the prepared polymer has the characteristics of controllable molecular weight and narrow polydispersity and conforms to the production concept of environment-friendly green production. The BINOL compound used in the invention has the advantages of low price, easy preparation, lower air sensitivity, better solubility, high modification easiness and longer shelf life. As a series of novel organic photocatalysts, the photocatalyst has very strong reducibility, can be changed from a ground state to an excited state under the action of illumination without adding amine additionally, and can reduce alkyl bromide to generate alkyl free radicals and bromine negative ions, thereby initiating the chain extension reaction of monomers and easily forming homopolymers and copolymers. The method avoids the toxicity of a polymer material prepared by a metal catalyst due to metal residues or initiates the degradation reaction of the polymer, can realize the controlled polymerization of a plurality of monomers and an initiator in proportion and with low catalyst dosage (0.01 percent relative to the monomers) at the temperature of between 20 ℃ below zero and 50 ℃, efficiently prepare the polymer with controllable molecular weight and narrow polydispersity, provide a new opportunity for the synthesis of photocatalytic macromolecules and micromolecules, better utilize the application of the polymer material prepared by the method in the aspects of food packaging, medical materials, electronic materials and the like, and accord with the production concept of environment-friendly green production.

Drawings

FIG. 1 is a GPC chart of the chain extension of an example tetrameric initiator and an example quincopolymerization experiment;

FIG. 2 is a first order kinetic diagram of an example homopolymer preparation;

FIG. 3 is a nuclear magnetic map representation of the polymer PMMA obtained in example III.

Detailed Description

In order to more clearly illustrate the solution in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly described below.