阅读说明：本技术 一种负载型催化剂及其在制备低分子量双端羟基聚苯醚中的应用 (Supported catalyst and application thereof in preparation of low-molecular-weight hydroxyl-terminated polyphenyl ether ) 是由 黄家辉 王奂 尚遇青 王晓光 于 2019-12-06 设计创作，主要内容包括：本发明公开了一种负载型催化剂及其在制备低分子量双端羟基聚苯醚中的应用,为经过表面改性的纳米氧化铝粒子表面接枝的咪唑类配体与金属离子的配合物；所述的经过表面改性的纳米氧化铝粒子为经过硅烷偶联剂改性的纳米氧化铝粒子；本发明催化剂催化效率高、选择性好,并可通过离心或过滤的方式从反应体系中分离出来,进行回收并实现循环利用。解决了目前催化剂在PPO生产过程中难以回收利用的问题。产物具有残留金属催化剂含量少、介电常数和介质损耗低、加工性能好等特点,制备过程简便易行,具有广阔的发展空间和极大的市场应用价值,适于工业化生产,符合可持续发展的要求。(The invention discloses a supported catalyst and application thereof in preparing low molecular weight double-end hydroxyl polyphenylene oxide, which is a complex of imidazole ligands and metal ions grafted on the surface of a nano-alumina particle subjected to surface modification; the surface-modified nano alumina particles are modified by a silane coupling agent; the catalyst has high catalytic efficiency and good selectivity, can be separated from a reaction system in a centrifugal or filtering mode, and is recycled and recycled. Solves the problem that the existing catalyst is difficult to recycle in the PPO production process. The product has the characteristics of low content of residual metal catalyst, low dielectric constant and dielectric loss, good processability and the like, the preparation process is simple and easy to implement, has wide development space and great market application value, is suitable for industrial production, and meets the requirement of sustainable development.)

1. The supported catalyst is characterized by being alumina nano particles modified by a silane coupling agent, wherein a complex is grafted on the surface of the alumina nano particles modified by the silane coupling agent; the complex is a complex of an imidazole ligand and metal ions;

the imidazole ligand is a cross-linked copolymer containing an N-vinyl imidazole monomer;

the metal ions are divalent copper ions or divalent manganese ions;

the N-vinyl imidazole monomer is a compound shown in a structural formula (I);

in the formula (I), R₁、R₂And R₃Independently is hydrogen or C₁～C₄Alkyl groups of (a);

in the complex, the molar ratio of the imidazole ligand to the metal ions is 0.5-200: 1.

2. A method of preparing a supported catalyst according to claim 1, comprising the steps of:

(1) dissolving a silane coupling agent and aluminum oxide nanoparticles in a mixed solvent of toluene and methanol to obtain a mixed solution, carrying out reflux reaction on the mixed solution at 110 ℃ for 24 hours, and after the reaction is finished, centrifuging, washing and drying to obtain silane coupling agent modified aluminum oxide nanoparticles; in the mixed solvent, the volume ratio of toluene to methanol is 2-9: 1;

(2) ultrasonically dispersing N-vinyl imidazole monomer, cross-linking agent and silane coupling agent modified alumina nano particles in ethyl acetate, adding initiator, and adding N₂Reacting for 24 hours at 110 ℃, drying and grinding to obtain the crosslinked polyvinyl imidazole ligand grafted on the surface of the alumina nano particles;

(3) respectively dissolving and dispersing a metal ion precursor and the crosslinked polyvinyl imidazole ligand grafted on the surface of the alumina nano particle in water, mixing and carrying out ultrasonic treatment for 30 minutes, centrifuging and drying to obtain the supported catalyst.

3. The method for preparing a supported catalyst according to claim 2, wherein when the metal ion is a divalent copper ion, the metal ion precursor is at least one of copper chloride, copper bromide, copper sulfate and copper nitrate;

when the metal ions are divalent manganese ions, the metal ion precursor is at least one of manganese chloride, manganese bromide, manganese iodide, manganese carbonate, manganese acetate, manganese nitrate, manganese sulfate and manganese phosphate.

4. The method for preparing the supported catalyst according to claim 3, wherein the silane coupling agent is one or more of 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldiethoxysilane, 4-mercaptobutyltrimethoxysilane and 4-mercaptobutyltriethoxysilane.

5. A process for preparing a supported catalyst according to claim 3 wherein the cross-linking agent is divinylbenzene or N, N' -methylene-bis (acrylamide); the initiator is at least one of azobisisobutyronitrile, azobisisoheptonitrile, potassium persulfate, sodium persulfate, ammonium persulfate, benzoyl peroxide, dicumyl peroxide, tert-butyl hydroperoxide and cumene hydroperoxide.

6. Use of the supported catalyst of claim 1 in oxidative copolymerization for the preparation of low molecular weight hydroxy-terminated polyphenylene ether; the oxidative copolymerization takes a phenol monomer, a bisphenol monomer and an oxidant as raw materials to prepare the low-molecular-weight hydroxyl-terminated polyphenyl ether in an oil-water two-phase medium; the structure of the phenol monomer is shown as a formula (II); the structure of the bisphenol monomer is shown as a formula (III); the structure of the low molecular weight double-end hydroxyl polyphenylene oxide is shown as a formula (IV);

R₄and R₅Independently hydrogen, alkyl with 1 to 4 carbon atoms, halogenated alkyl, aminoalkyl or alkoxy; r₆Is hydrogen or halogen;

R₇、R₈、R₉、R₁₀、R₁₁and R₁₂Independently hydrogen, alkyl with 1 to 4 carbon atoms, halogenated alkyl, aminoalkyl or alkoxy;

the number average molecular weight of the low molecular weight double-end hydroxyl polyphenylene oxide is 1000-8000.

7. The use according to claim 6, wherein the oxidative copolymerization reaction comprises the following raw materials in a molar ratio:

wherein the sum of the molar ratio composition of the phenol monomer and the bisphenol monomer is 1.

8. The use of claim 6, wherein the oxidative copolymerization reaction temperature is 10 ℃ to 80 ℃, the reaction time is 4 hours to 72 hours, and the pressure is 0.1MPa to 5.0 MPa.

9. The use according to claim 6, wherein in the oxidative copolymerization, the oil phase in the oil-water two-phase medium is at least one of benzene, toluene, nitrobenzene, chloroform or dichloromethane; the volume ratio of the oil phase to the water phase is 50-10: 1.

10. The use of claim 6, wherein the oxidant is oxygen, air or a mixture of oxygen and an inert gas; in the mixed gas of the oxygen and the inert gas, the volume ratio of the oxygen to the inert gas is 0.05-100: 1; the inert gas is at least one of carbon dioxide, nitrogen, helium, neon and argon.

Technical Field

The invention relates to the technical field of polymer chemical industry, in particular to a supported catalyst, a preparation method thereof and application of the supported catalyst in preparation of low-molecular-weight hydroxyl-terminated polyphenyl ether in an oil-water two-phase medium.

Background

Polyphenylene Oxide (PPO) is an engineering plastic with excellent comprehensive performance, not only has good mechanical properties, but also has outstanding performances such as low dielectric constant, low dielectric loss, low hygroscopicity, high glass transition temperature, acid and alkali corrosion resistance and the like, thereby having wide application prospects in the fields of automobile parts, electronic devices, office equipment, coatings, additives and the like. However, as a thermoplastic resin, high molecular weight PPO has high melt viscosity, poor processability, and low reactivity when used in additives and composites. The low molecular weight double-end hydroxyl PPO oligomer not only has all the excellent properties of the common single-end hydroxyl PPO, such as dimensional stability, low dielectric constant and the like, but also becomes a very useful modifier due to the reactivity and is easy to process.

The traditional synthesis methods of low molecular weight double-end hydroxyl PPO mainly comprise three methods. 1. Carrying out redistribution reaction on high molecular weight PPO and diphenol monomer, and degrading to obtain low molecular weight hydroxyl-terminated polyphenyl ether, wherein the molecular weight of the product is bimodal distribution; 2. two molecules of low molecular weight polyphenylene ether and trioxymethylene are condensed under the catalysis of Lewis acid to obtain low molecular weight double-end hydroxyl polyphenylene ether, however, the preparation of the low molecular weight polyphenylene ether has great difficulty; 3. DMP and 3,3 ', 5, 5' -tetramethyl bisphenol A carry out copolymerization reaction, but the copolymerization reaction carried out in an organic solvent is very quick, and the molecular weight and the structure of the product are difficult to control. Therefore, the continuous and accurate regulation and control of the molecular weight in the one-step production of the low molecular weight dihydroxy-terminated polyphenylene oxide is still an unsolved technical problem.

The recycling of the catalyst can greatly reduce the production cost, save resources, reduce the discharge of three wastes and have high economic and environmental protection values. At present, catalysts for synthesizing polyphenylene oxide are mainly homogeneous and are not easy to separate, the catalysts are loaded on inert carriers, and the catalysts can be separated by simple filtration or centrifugation means after the reaction is finished, but the catalytic efficiency of the catalysts is greatly reduced, so that the recycling of PPO catalysts still remains to be solved.

Disclosure of Invention

The invention provides a supported catalyst which has high catalytic efficiency and good selectivity and is easy to recycle.

The invention also provides a preparation method of the supported catalyst, which is simple to operate and easy to control, and the composition of the catalyst can be adjusted according to production requirements so as to adjust the performance index of the product.

The invention also provides a method for preparing low molecular weight hydroxyl-terminated polyphenylene oxide by using the supported catalyst in an oil-water two-phase medium, wherein the catalyst can be recovered and reused as expected.

A supported catalyst is an alumina nanoparticle modified by a silane coupling agent, and a complex is grafted on the surface of the alumina nanoparticle modified by the silane coupling agent; the complex is a complex of an imidazole ligand and metal ions;

the imidazole ligand is a cross-linked copolymer containing an N-vinyl imidazole monomer;

the metal ions are divalent copper ions or divalent manganese ions;

wherein the N-vinyl imidazole monomer is a compound shown in a structural formula (I);

in the formula (I), R₁、R₂And R₃Independently is hydrogen or C₁～C₄Alkyl groups of (a);

the molar ratio of the imidazole monomer to the metal ions in the complex is 0.5-200: 1, the molar ratio of the imidazole monomer to the metal ions is preferably 2-20: 1, and within the range, the reaction rate is higher, the selectivity is better, and the yield of the polyphenyl ether is higher.

The invention also provides a preparation method of the supported catalyst, which comprises the following steps:

(1) dissolving a silane coupling agent and aluminum oxide nanoparticles in a mixed solvent of toluene and methanol to obtain a mixed solution, carrying out reflux reaction on the mixed solution at 110 ℃ for 24 hours, and after the reaction is finished, centrifuging, washing and drying to obtain silane coupling agent modified aluminum oxide nanoparticles; the volume ratio of the toluene to the methanol is 2-9: 1; the step (1) can be summarized as follows: carrying out coupling reaction on the alumina nano particles and a silane coupling agent to obtain surface-modified nano alumina;

(2) ultrasonically dispersing imidazole monomers, a cross-linking agent and the silane coupling agent modified aluminum oxide nanoparticles in ethyl acetate, adding an initiator, and adding N₂Reacting for 24 hours at 110 ℃, drying and grinding to obtain the crosslinked polyvinyl imidazole ligand grafted on the surface of the alumina nano particles; the step (2) can be summarized as follows: initiating a crosslinking copolymerization reaction of vinyl imidazole monomers and a crosslinking agent by free radicals in the presence of the surface-modified nano alumina particles;

(3) respectively dissolving and dispersing a metal ion precursor and the crosslinked polyvinyl imidazole ligand grafted on the surface of the alumina nano particle in water, mixing and carrying out ultrasonic treatment for 30 minutes, centrifuging and drying to obtain the supported catalyst; the step (3) can be summarized as that the imidazole group and the metal ion are subjected to coordination reaction to prepare the supported catalyst.

Based on the technical scheme, preferably, when the metal ions are divalent copper ions, the metal ion precursor is at least one of copper chloride, copper bromide, copper sulfate and copper nitrate;

based on the above technical scheme, preferably, when the metal ion is a divalent manganese ion, the metal ion precursor is at least one of manganese chloride, manganese bromide, manganese iodide, manganese carbonate, manganese acetate, manganese nitrate, manganese sulfate and manganese phosphate.

Based on the technical scheme, preferably, the silane coupling agent is one or more of 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldiethoxysilane, 4-mercaptobutyltrimethoxysilane and 4-mercaptobutyltriethoxysilane;

based on the technical scheme, the cross-linking agent is preferably divinylbenzene or N, N' -methylene-bis (acrylamide); the initiator, the azodiisoheptonitrile, the potassium persulfate, the sodium persulfate, the ammonium persulfate, the benzoyl peroxide, the dicumyl peroxide, the tert-butyl hydroperoxide and the cumene hydroperoxide.

The invention also provides an application of the supported catalyst, and the supported catalyst can be used for preparing low-molecular-weight hydroxyl-terminated polyphenyl ether in an oil-water two-phase medium and can be used for catalyzing oxidative polymerization reaction for preparing the low-molecular-weight hydroxyl-terminated polyphenyl ether in the oil-water two-phase medium by taking a phenol monomer, a bisphenol monomer and an oxidant as raw materials.

The supported catalyst can be separated and recycled by a filtering or centrifuging method after the oxidative polymerization reaction is finished.

The method for preparing the low-molecular-weight hydroxyl-terminated polyphenyl ether in the oil-water two-phase medium by using the supported catalyst comprises the following steps: dissolving a phenol monomer and a bisphenol monomer in an organic solvent, dispersing a supported catalyst in water, mixing oil and water, carrying out oxidative polymerization reaction in the presence of an oxidant, standing for layering after the reaction is finished, separating the supported catalyst from a reaction system by using a filtering or centrifuging method, washing and drying the recovered supported catalyst, and recycling the catalyst for the next reaction. And (3) taking methanol as a precipitator for the reaction product, and filtering and separating to obtain the crosslinkable polyphenyl ether.

The phenol monomer and the bisphenol monomer are respectively compounds shown in the structures of a formula (II) and a formula (III):

R₄and R₅Independently hydrogen, alkyl with 1 to 4 carbon atoms, halogenated alkyl, aminoalkyl or alkoxy;

R₆is hydrogen or halogen;

R₇、R₈、R₉、R₁₀、R₁₁and R₁₂Independently hydrogen, alkyl with 1 to 4 carbon atoms, halogenated alkyl, amino alkyl or alkoxy

The number average molecular weight of the low molecular weight double-end hydroxyl polyphenylene oxide is 1000-8000.

Based on the above technical scheme, preferably, the molar ratio of the raw materials in the oxidative copolymerization reaction is as follows:

wherein the sum of the molar ratio composition of the phenol monomer and the bisphenol monomer is 1.

The temperature of the oxidation copolymerization reaction is 10-80 ℃, preferably 20-60 ℃, the reaction rate is high in the temperature range, and reaction byproducts are few; the reaction time is 4 to 72 hours; the pressure is 0.1MPa to 5.0MPa, preferably 0.1MPa to 2.0MPa, and the pressure range has higher safety in industrial production operation.

The oxidative copolymerization medium oil phase is one or more of good solvents of phenol monomers such as benzene, toluene, nitrobenzene, trichloromethane or dichloromethane and the like; the volume ratio of oil to water is 50-10: 1.

The oxidant is oxygen, air or mixed gas formed by mixing oxygen and inert gas; in the mixed gas of the oxygen and the inert gas, the volume ratio of the oxygen to the inert gas is 0.05-100: 1; the inert gas is one or a mixture of more of carbon dioxide, nitrogen, helium, neon and argon in any proportion; the oxidizing effect of the mixed gas is oxygen, so that the amount of the oxidant is calculated by the oxygen in the invention.

Advantageous effects

(1) The catalyst combines the characteristics of the nano particles and the metal ion-crosslinked polyvinyl imidazole ligand complex; the nano particles are used as the carrier of the catalyst, have small size and large specific surface area, so that the catalyst is fully contacted with a reaction substrate, have high catalytic efficiency and are beneficial to effective loading and catalysis of the catalyst, and meanwhile, the nano particles are the core of the catalyst, and the catalyst can be recovered in a centrifugal or filtering mode. The obtained low molecular weight double-end hydroxyl polyphenylene oxide has the characteristics of low content of residual metal catalyst, low dielectric constant and dielectric loss, good processability and the like.

(2) The preparation method disclosed by the invention is simple and easy to operate, has wide development space and great market application value, is suitable for industrial production, meets the requirement of sustainable development, is easy to control, and is suitable for industrial production.

Drawings

FIG. 1 is a schematic diagram of the structure of a supported catalyst according to the present invention; wherein: the curve of class a represents- (CH-CH)₂) -a crosslinked network formed by copolymerization with a crosslinking agent; the b-type curve represents the omitted cross-linked network.

Detailed Description