Supported catalyst and application thereof in preparation of remote-claw type low molecular weight polyphenylene ether
阅读说明：本技术 一种负载型催化剂及其在制备遥爪型低分子量聚苯醚中的应用 (Supported catalyst and application thereof in preparation of remote-claw type low molecular weight polyphenylene ether ) 是由 黄家辉 王奂 张好磊 郎绪志 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,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,遥爪型低分子量PPO既可以进行自身的交联反应,也可以通过末端双键与其他物质反应进行化学改性,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 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 telechelic low-molecular-weight PPO can be subjected to self-crosslinking reaction and can also be subjected to chemical modification through the reaction of a terminal double bond with other substances, the preparation process is simple and easy to implement, the product has wide development space and great market application value, is suitable for industrial production and meets the requirement of sustainable development.)
1. A method for producing a telechelic low-molecular-weight polyphenylene ether, characterized by comprising the steps of:
(1) reacting low-molecular-weight double-end hydroxyl polyphenylene oxide and acyl chloride or acid anhydride serving as raw materials in a toluene solvent at the temperature of 30-90 ℃ for 2-20 hours to obtain a reaction solution;
(2) adding the reaction solution into a hydrochloric acid-methanol mixed solution, filtering, repeatedly dissolving and precipitating a product obtained by filtering for three times by using toluene-methanol, and drying to obtain the remote claw type low molecular weight polyphenylene ether; in the hydrochloric acid-methanol mixed solution, the concentration of the hydrochloric acid is 0.5-5 wt%.
2. The production method according to claim 1,
the polyacyl chloride is methacryloyl chloride;
the acid anhydride is one or more of methacrylic anhydride and maleic anhydride;
the molar ratio of the low-molecular-weight hydroxyl-terminated polyphenyl ether to the acyl chloride or the anhydride is 1: 2-10.
3. The preparation method of claim 1, wherein the low molecular weight bis-hydroxyl-terminated polyphenylene oxide is prepared by using a supported catalyst to catalyze the oxidative copolymerization reaction of the raw materials of the phenol monomer, the bisphenol monomer and the oxidant in an oil-water two-phase medium; the number average molecular weight of the low molecular weight double-end hydroxyl polyphenylene oxide is 1000-8000;
the supported catalyst is an alumina nano particle modified by a silane coupling agent, and a complex is grafted on the surface of the alumina nano particle 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;
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 R5Is hydrogen, alkyl, haloalkyl, aminoalkyl or alkoxy having 1 to 4 carbon atoms, R6Is hydrogen or halogen;
R7、R8、R9、R10、R11and R12Independently hydrogen, alkyl with 1 to 4 carbon atoms, halogenated alkyl, amino alkyl or alkoxy.
4. The preparation method according to claim 3, wherein 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.
5. The preparation method according to claim 3, wherein the temperature of the oxidative copolymerization reaction is 10 ℃ to 80 ℃, the reaction time is 4 hours to 72 hours, and the pressure is usually 0.1MPa to 5.0 MPa; the reaction temperature in the step (2) is 30-90 ℃.
6. The preparation method according to claim 3, wherein the oil phase in the oil-water medium in the oxidative copolymerization reaction 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.
7. The method according to claim 3, wherein the oxidizing agent 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.
8. The method according to claim 3, wherein the supported catalyst is prepared by the following steps:
(1) dispersing 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 imidazole ligand, cross-linking agent and silane coupling agent modified aluminum oxide nanoparticles into 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.
9. The method according to claim 8, wherein when the metal ion is a cupric ion, the metal ion precursor is at least one of cupric chloride, cupric bromide, cupric sulfate and cupric 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.
10. The preparation method according to claim 8, wherein the silane coupling agent is one or more of 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldiethoxysilane, 4-mercaptobutyltrimethoxysilane and 4-mercaptobutyltriethoxysilane;
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.
Technical Field
The invention relates to the technical field of polymer chemical engineering, in particular to a supported catalyst, a preparation method thereof and application of the supported catalyst in preparation of a remote claw type low molecular weight polyphenylene 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 polyphenylene ether can overcome many disadvantages, and the main method for industrially producing the low molecular weight polyphenylene ether at present is redistribution reaction, and the redistribution reaction of PPO has been intensively studied by GE plastics of original U.S. and Asahi chemical company of Japan, and many patents on redistribution reaction for synthesis of low molecular weight polyphenylene ether have been filed, such as U.S. Pat. Nos. 7858726, U.S. Pat. No. 7282554, U.S. Pat. No. 6211327, U.S. Pat. No. 3962180, U.S. Pat. No. 6455663, U.S. Pat. No. 0254257, etc., as well as methods using continuous feeding in small amounts, using. However, ordinary low molecular weight PPO can only react by means of terminal hydroxyl, and it is often difficult to meet the requirements in practical applications, and the above production method is cumbersome, and often a product cannot be obtained by one-step method or precise regulation of molecular weight cannot be achieved, and the catalyst is also difficult to recover and reuse. The remote claw type low molecular weight PPO not only has all excellent properties of common PPO, such as dimensional stability, low dielectric constant and the like, but also becomes a very useful modifier due to the reaction activity, is easy to process, and opens up a wider space for the application of PPO. 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.
The invention provides a preparation method of telechelic low molecular weight polyphenylene ether, which comprises the following steps:
(1) reacting low-molecular-weight double-end hydroxyl polyphenylene oxide and acyl chloride or acid anhydride serving as raw materials in a toluene solvent at the temperature of 30-90 ℃ for 2-20 hours to obtain a reaction solution;
(2) adding the reaction solution into a hydrochloric acid-methanol mixed solution, filtering, repeatedly dissolving and precipitating a product obtained by filtering for three times by using toluene-methanol, and drying to obtain the remote claw type low molecular weight polyphenylene ether; in the hydrochloric acid-methanol mixed solution, the concentration of the hydrochloric acid is 0.5-5 wt%.
Based on the technical scheme, the preferable reaction temperature is 60-80 ℃, the reaction time is 6-8 hours, the reaction rate is high under the reaction condition, and the volatilization amount of the raw materials is small.
The polyacyl chloride is methacryloyl chloride;
the acid anhydride is one or more of methacrylic anhydride and maleic anhydride;
the molar ratio of the low-molecular-weight hydroxyl-terminated polyphenyl ether to the acyl chloride or the anhydride is 1: 2-10.
Based on the technical scheme, the preferable molar ratio of the low-molecular-weight hydroxyl-terminated polyphenyl ether to the acyl chloride or the anhydride is 1: 5-8, the ratio range can ensure that the terminal hydroxyl of the polyphenyl ether can be reacted sufficiently, and meanwhile, the economic benefit is considered.
The low molecular weight hydroxyl-terminated polyphenyl ether is prepared by catalyzing a phenol monomer, a bisphenol monomer and an oxidant in an oil-water two-phase medium by using a supported catalyst to perform an oxidation copolymerization reaction; the oxidant is oxygen, air or mixed gas formed by mixing oxygen and inert gas, and the mixed gas plays an oxidizing role in being oxygen, so the oxidant is used in the amount counted by oxygen in the invention.
In practice, oxygen is not metered and is generally added in excess, so that the upper limit of the amount of the oxidant is not strictly limited.
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 R5Is hydrogen, alkyl, haloalkyl, aminoalkyl or alkoxy having 1 to 4 carbon atoms, 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;
the supported catalyst is an alumina nano particle modified by a silane coupling agent, and a complex is grafted on the surface of the alumina nano particle 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, and the molar ratio of the imidazole monomer to the metal ions is preferably 2-20: 1, so that the reaction rate is higher, the selectivity is better, and the yield of the polyphenyl ether is higher. .
The mol ratio of the raw materials in the oxidation 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 oil phase in the oil-water medium in the oxidation copolymerization reaction is at least one of benzene, toluene, nitrobenzene, trichloromethane or dichloromethane; the volume ratio of the oil phase to the water phase is 50-10: 1.
The oxidant is oxygen, air or a mixed gas of 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 at least one of carbon dioxide, nitrogen, helium, neon and argon.
The preparation steps of the supported catalyst are as follows:
(1) dispersing 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 imidazole ligand, cross-linking agent and silane coupling agent modified aluminum oxide nanoparticles into 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.
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 dihydroxy-terminated polyphenylene oxide.
When the metal ions are bivalent copper ions, 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.
The silane coupling agent is one or more of 3-mercaptopropyl trimethoxysilane, 3-mercaptopropyl triethoxysilane, 3-mercaptopropyl methyldimethoxysilane, 3-mercaptopropyl methyldiethoxysilane, 4-mercaptobutyl trimethoxysilane and 4-mercaptobutyl triethoxysilane;
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.
Advantageous effects
(1) The method for synthesizing the remote-claw type low-molecular-weight PPO has simple steps, and realizes the accurate regulation and control of the molecular weight according to the requirements.
(2) 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.
(3) The product of the invention is characterized by low content of residual metal catalyst, low dielectric constant and dielectric loss, good processing performance and the like; the application space is wide.
(3) 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
- 上一篇：一种医用注射器针头装配设备
- 下一篇：一种共聚半芳香尼龙的合成方法