Ultrahigh molecular weight star-shaped polyvinylpyrrolidone and synthesis method thereof
阅读说明：本技术 超高分子量星型聚乙烯基吡咯烷酮及其合成方法 (Ultrahigh molecular weight star-shaped polyvinylpyrrolidone and synthesis method thereof ) 是由 安泽胜 李若雨 于 2020-07-29 设计创作，主要内容包括：本发明涉及一种超高分子量星型聚乙烯基吡咯烷酮及其制备方法。该方法首先合成星型链转移剂,然后通过控制星型链转移剂与N-乙烯基吡咯烷酮的比例,以葡萄糖氧化酶为催化剂,在光照的条件下无需除氧合成分子量可控的超高分子量星型聚乙烯基吡咯烷酮。聚合过程简单易操作,聚合之前无需除氧,提高了聚合效率并降低了设备费用；合成可在水溶液中进行,也可以在水溶液与乙腈的混合溶液中进行,增加了反应体系的多样性。合成的超高分子量星型聚乙烯基吡咯烷酮分子量可控且分子量分布窄,具有紧凑的空间三维结构,并增加了进一步功能化的机会。(The invention relates to star-shaped polyvinylpyrrolidone with ultrahigh molecular weight and a preparation method thereof. The method comprises the steps of firstly synthesizing a star-shaped chain transfer agent, then synthesizing the ultrahigh molecular weight star-shaped polyvinylpyrrolidone with controllable molecular weight without removing oxygen under the condition of illumination by controlling the proportion of the star-shaped chain transfer agent to N-vinyl pyrrolidone and taking glucose oxidase as a catalyst. The polymerization process is simple and easy to operate, and oxygen removal is not needed before polymerization, so that the polymerization efficiency is improved, and the equipment cost is reduced; the synthesis can be carried out in aqueous solution or mixed solution of the aqueous solution and acetonitrile, and the diversity of the reaction system is increased. The synthesized ultrahigh molecular weight star-shaped polyvinylpyrrolidone has controllable molecular weight, narrow molecular weight distribution, compact space three-dimensional structure and increased opportunity of further functionalization.)
1. The ultrahigh molecular weight star-shaped polyvinylpyrrolidone is characterized in that the structural formula of the ultrahigh molecular weight star-shaped polyvinylpyrrolidone is as follows:
R1is alkylene containing 1 to 18 carbons
R2Is an alkyl, alkylbenzene, cyano, carboxyl or ester group containing 1-18 carbons
R3Is H or an alkyl, alkylbenzene, cyano, carboxyl or ester group containing 1 to 18 carbons
R4Is an alkyl, alkylbenzene, cyano, carboxyl or ester group containing 1-18 carbons
n is: 1000-10000, the molecular weight of the obtained star-shaped polyvinylpyrrolidone is not less than 200000 g/mol;
core is the crosslink point of the star-shaped polyvinylpyrrolidone arms.
2. The ultrahigh molecular weight star-shaped polyvinylpyrrolidone of claim 1, wherein the ultrahigh molecular weight star-shaped polyvinylpyrrolidone has a structural formula:
3. the ultra-high molecular weight star polyvinylpyrrolidone of claim 1, wherein the ultra-high molecular weight star polyvinylpyrrolidone has a dispersity of less than 1.35.
4. A process for the preparation of the ultra-high molecular weight star polyvinylpyrrolidone of claim 1, 2 or 3, characterized by the specific steps of:
a. dissolving a hydroxyl-containing multi-arm compound and bromopropionyl bromide in trichloromethane according to the molar ratio of hydroxyl to carbonyl functional groups of 1 to (1.05-1.5) until the reactants are fully dissolved, and stirring for reaction for 10-48 hours to obtain a multi-arm star-shaped brominated precursor, wherein the structural formula of the precursor is as follows:the hydroxyl-containing multi-arm compound has a structural formula as follows:
b. b, dissolving the multi-arm star-shaped brominated precursor and the xanthate obtained in the step a in trichloromethane according to the molar ratio of the functional group 1 to (1.1-2.5) until the reactants are fully dissolved, stirring and reacting for 10-48 hours to obtain a crude product, and purifying the crude product to obtain a star-shaped chain transfer agent, wherein the structural formula of the star-shaped chain transfer agent is as follows:the structural formula of the xanthate is as follows:
c. and c, adding the star-shaped chain transfer agent obtained in the step b and N-vinyl pyrrolidone into 20mM PBS buffer solution with pH of 7 according to a molar ratio of 1: 1000-50000, adding glucose and glucose oxidase to make the concentrations of the glucose and glucose oxidase be 0.1-100mM and 0.1-200 mu M respectively, and reacting for 18-48 hours at-5-40 ℃ under the irradiation of purple or blue light to obtain the ultrahigh molecular weight star-shaped polyvinylpyrrolidone.
Technical Field
The invention relates to water-soluble star-shaped high polymer-star-shaped polyvinylpyrrolidone used in the fields of personal care, drug delivery, food, daily chemical industry and the like and a synthesis method thereof, in particular to ultra-high molecular weight star-shaped polyvinylpyrrolidone and a synthesis method thereof.
Background
Star polyvinylpyrrolidone (PNVP) is a highly functionalized polymeric material with a compact spatial three-dimensional structure that gives it unique physical properties and increases the opportunity for further functionalization. Due to the unique structure of star-shaped PNVP, star-shaped PNVP exhibits some significant features and properties not achieved by simple linear PNVP. The star-shaped PNVP has the advantages of good water solubility, strong thermal stability and the like, is used as a viscosity modifier and a lubricant in industry at present, and is also under research in potential application in the fields of drug carriers, interface stabilizers and the like.
N-vinyl pyrrolidone (NVP) is a non-conjugated monomer, and the synthesis of linear PNVP with controllable molecular weight and low dispersity is difficult; the synthesis of star-shaped PNVP, especially ultra-high molecular weight star-shaped PNVP, is more difficult. The development of controlled radical polymerization has facilitated the synthesis of star-shaped PNVP. The star-shaped PNVP can be synthesized by Atom Transfer Radical Polymerization (ATRP), nitroxide-regulated polymerization (NMP), ring-opening polymerization (ROP) and other controllable polymerization methods. However, the PNVP synthesized by the method has low molecular weight and large dispersity, and is not beneficial to further modification and application of products.
To date, most PNVP have been synthesized by reversible addition fragmentation chain transfer polymerization (RAFT). Conventional thermally initiated RAFT polymerisation requires continuous heating of the reaction during the synthesis of the PNVP, which not only consumes resources but also is prone to environmental pollution. As the reaction proceeds, the concentration of initiator radicals gradually decays, failing to continue the reaction, resulting in a low molecular weight of the synthesized PNVP. RAFT polymerisation is easily inhibited or quenched by oxygen and requires that the reaction apparatus be deoxygenated prior to polymerisation. The manual deoxidization increases the operation difficulty and increases the equipment cost.
The development of photo-regulated polymerization has promoted the further development of RAFT polymerization. However, most of the light-operated RAFT polymerization uses a toxic catalyst, and the development of a more environment-friendly and green catalytic system is more meaningful.
Disclosure of Invention
The invention aims to provide the ultrahigh molecular weight star-shaped polyvinylpyrrolidone.
The invention also aims to provide a preparation method of the ultrahigh molecular weight star-shaped polyvinylpyrrolidone, which can be used for simply and efficiently synthesizing the ultrahigh molecular weight star-shaped PNVP in a PBS buffer solution or a mixed solution of PBS and acetonitrile at room temperature or below in the presence of oxygen.
The enzyme is a natural catalyst existing in nature, and has the advantages of high efficiency, high selectivity and the like. When the enzyme is used as the catalyst, high temperature and high pressure are not needed, and the reaction condition is very mild. The invention combines light-operated polymerization and enzyme-catalyzed RAFT polymerization to develop a method for synthesizing the ultra-high molecular weight star-shaped PNVP. The method has high synthesis efficiency and low production cost, greatly improves the molecular weight of star-shaped PVNP, and reduces the dispersion degree of star-shaped PNVP.
The star-shaped PNVP can be synthesized by the method in a PBS buffer (20mM, pH 7) at-5-40 ℃ or a mixed solution of the PBS buffer and acetonitrile. The whole polymerization process does not need to remove oxygen, and the ultra-high molecular weight star-shaped PNVP with controllable molecular weight and low dispersity can be synthesized by consuming lower energy. The star-shaped PNVP synthesized by the method has the molecular weight as high as 106g/mol, and narrow molecular weight distributionThe method can synthesize the ultra-high molecular weight star-shaped PNVP with different arm numbers by changing the type of the chain transfer agent. The star-shaped PNVP with different molecular weights can also be obtained by changing the ratio of the chain transfer agent to NVP.
The invention adopts the photocatalysis RAFT polymerization to synthesize the ultra-high molecular weight star-shaped PNVP by two steps, which is shown in figure 1. The natural oxygen removing function of the glucose oxidase is combined with the photocatalysis function of the glucose oxidase, so that the optically controlled RAFT polymerization with oxygen tolerance is realized.
Firstly, synthesizing a star-shaped chain transfer agent through an organic reaction; and step two, synthesizing the ultra-high molecular weight star-shaped PNVP through the photocatalytic RAFT polymerization. The glucose oxidase plays a role in oxygen removal and catalysis in the polymerization process. Through non-natural photocatalyst catalysis, free radicals are maintained at a relatively low but stable level, so that the ultra-high molecular weight star-shaped PNVP can be synthesized under mild conditions.
The synthesis mechanism of the chain transfer agent in the first step is as follows:
R1is alkylene containing 1 to 18 carbons
R2Is alkyl, alkylbenzene, cyano, carboxyl and ester group containing 1-18 carbon atoms
R3Is H or alkyl, alkylbenzene, cyano, carboxyl or ester group containing 1-18 carbon atoms
R4Is alkyl, alkylbenzene, cyano, carboxyl and ester group containing 1-18 carbon atoms
The core (core) is the crosslink point of the multi-arm star-shaped brominated precursor.
The reaction mechanism of synthesizing the ultra-high molecular weight star-shaped PNVP through the photocatalytic RAFT polymerization in the second step is as follows:
R1is alkylene containing 1 to 18 carbons
R2Is alkyl, alkylbenzene, cyano, carboxyl and ester group containing 1-18 carbon atoms
R3Is H or alkyl, alkylbenzene, cyano, carboxyl or ester group containing 1-18 carbon atoms
R4Is alkyl, alkylbenzene, cyano, carboxyl and ester group containing 1-18 carbon atoms
According to the reaction mechanism, the invention adopts the following technical scheme:
the ultrahigh molecular weight star-shaped polyvinylpyrrolidone is characterized in that the structural formula of the ultrahigh molecular weight star-shaped polyvinylpyrrolidone is as follows:
R1is alkylene containing 1 to 18 carbons
R2Is an alkyl, alkylbenzene, cyano, carboxyl or ester group containing 1-18 carbons
R3Is H or an alkyl, alkylbenzene, cyano, carboxyl or ester group containing 1 to 18 carbons
R4To contain 1Alkyl, alkylbenzene, cyano, carboxyl or ester group of 18 carbons
n is: 1000-10000
Core is the crosslinking point of the arms of the star-shaped polyvinylpyrrolidone, and the molecular weight of the obtained star-shaped polyvinylpyrrolidone is not less than 200000 g/mol.
The structural formula of the ultrahigh molecular weight star-shaped polyvinylpyrrolidone is as follows:
the dispersity of the ultrahigh molecular weight star-shaped polyvinylpyrrolidone is less than 1.33.
The method for preparing the ultrahigh molecular weight star-shaped polyvinylpyrrolidone is characterized by comprising the following specific steps:
a. hydroxyl-containing multi-arm compounds and bromopropionyl bromide were reacted according to the ratio of hydroxyl and carbonyl functional groups 1: (1.05-1.5) until the reactant is fully dissolved, stirring and reacting for 10-48 hours to obtain a multi-arm star-shaped brominated precursor, wherein the structural formula of the precursor is as follows:
b. b, mixing the multi-arm star-shaped brominated precursor obtained in the step a and xanthate according to the ratio of the functional group 1: (1.1-2.5) dissolving in chloroform until the reactant is fully dissolved, stirring for reaction for 10-48 hours to obtain a crude product, and purifying the crude product to obtain the star-shaped chain transfer agent, wherein the structural formula of the star-shaped chain transfer agent is as follows:
c. and c, adding the star-shaped chain transfer agent obtained in the step b and N-vinyl pyrrolidone into 20mM PBS buffer solution with pH of 7 according to a molar ratio of 1 (1000-50000), adding glucose and glucose oxidase to make the concentrations of the glucose and glucose oxidase be 0.1-100mM and 0.1-200 mu M respectively, and reacting for 18-48 hours at-5-40 ℃ under the irradiation of purple or blue light to obtain the ultrahigh molecular weight star-shaped polyvinylpyrrolidone.
The star-shaped polyvinylpyrrolidone with the ultrahigh molecular weight has controllable molecular weight, narrow molecular weight distribution and compact space three-dimensional structure, and provides possibility for further functionalization. The method has simple and easy operation of polymerization process, does not need to remove oxygen before polymerization, improves the polymerization efficiency and reduces the equipment cost; the synthesis of the ultrahigh molecular weight star-shaped polyvinylpyrrolidone can be carried out in an aqueous solution or a mixed solution of the aqueous solution and acetonitrile, so that the diversity of a reaction system is increased.
Drawings
FIG. 1 is a hydrogen spectrum of example one of the present invention.
FIG. 2 is a hydrogen spectrum of example two of the present invention.
FIG. 3 is a GPC chart of example two of the present invention.
FIG. 4 is a hydrogen spectrum of example three of the present invention.
FIG. 5 is a GPC chart of example three of the present invention.
Detailed Description
According to