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CN-117164825-B - Conductive polymer with TEMPO-containing side chain, and preparation method and application thereof

CN117164825BCN 117164825 BCN117164825 BCN 117164825BCN-117164825-B

Abstract

The invention relates to the technical field of electrochemistry, and discloses a conductive polymer with a side chain containing TEMPO, and a preparation method and application thereof. At present, the preparation of 2, 5-diformylfuran by using 5-hydroxymethyl furfural as a raw material has the problem of difficult recovery of a catalyst and separation of the catalyst from a product. In order to solve the technical problems, the invention realizes heterogeneous electrochemical catalytic oxidation of 5-hydroxymethylfurfural by TEMPO to generate 2, 5-diformylfuran by connecting a small molecular catalyst TEMPO to a conductive polymer and connecting the conductive polymer obtained by connection. The conductive polymer is used as a catalyst for preparing 2, 5-diformylfuran by electrocatalytic oxidation of 5-hydroxymethylfurfural, so that the problem of difficult separation of the catalyst and a product is avoided, and the conductive polymer has the characteristics of high reaction rate and high product yield.

Inventors

  • LI MEICHAO
  • ZHANG CHUANYE
  • SHEN ZHENLU

Assignees

  • 浙江工业大学

Dates

Publication Date
20260508
Application Date
20230905

Claims (8)

  1. 1. A preparation method of a conductive polymer with a TEMPO-containing side chain is characterized by comprising the following steps: (1) Taking (4- (2, 3-dihydrothiophene [3,4-b ] [1,4] dioxin-2-yl) methoxy) -4-oxybutyric acid and 4-hydroxy-2, 6-tetramethyl piperidine nitroxide free radical as reaction raw materials, adding a catalyst and a dehydrating agent, and reacting to obtain 4- ((4- ((2, 3-dihydrothiophene [3,4-b ] [1,4] dioxin-2-yl) methoxy) -4-oxo butyryl) oxy) -2, 6-tetramethyl piperidine-1-oxy free radical; (2) Adopting a three-electrode system, wherein a working electrode and an auxiliary electrode are Pt electrodes, the reference electrode is an Ag/Ag+ electrode, and adding a monomer 4- ((4- ((2, 3-dihydrothiophene [3,4-b ] [1,4] dioxin-2-yl) methoxy) -4-oxo-butyryl) oxy) -2, 6-tetramethylpiperidine-1-oxy free radical and 2,2 '-dithiophene into a dichloromethane solution containing tetrabutylammonium perchlorate to perform electropolymerization reaction, wherein the mass ratio of the monomer 4- ((4- ((2, 3-dihydrothiophene [3,4-b ] [1,4] dioxin-2-yl) methoxy) -4-oxo-butyryl) oxy) -2, 6-tetramethylpiperidine-1-oxy free radical and 2,2' -dithiophene is 1:0.2-0.8; (3) After the electropolymerization reaction is finished, the surface of the working electrode is washed and dried, and the conductive polymer film with TEMPO attached to the side chain of the surface of the working electrode is obtained.
  2. 2. The method according to claim 1, wherein in the step (1), the ratio of the amount of the substance of (4- (2, 3-dihydrothiophene [3,4-b ] [1,4] dioxin-2-yl) methoxy) -4-oxybutyric acid to the amount of the substance of 4-hydroxy-2, 6-tetramethylpiperidine nitroxide is 1:1 to 1.5.
  3. 3. The method according to claim 1, wherein in the step (1), the catalyst is 4-dimethylaminopyridine.
  4. 4. The process according to claim 1, wherein in the step (1), the dehydrating agent is dicyclohexylcarbodiimide.
  5. 5. The method of claim 1, wherein in the step (1), the reaction time is 14 to 18 hours.
  6. 6. The method according to claim 1, wherein in the step (2), the mass concentration of tetrabutylammonium perchlorate in a methylene chloride solution is 0.1 to 0.15mol/L.
  7. 7. The method of claim 1, wherein in the step (2), the electropolymerization has a polymerization potential of-0.5 to 1.5V, a scanning speed of 50 mV/s and a number of scanning turns of 4 to 10.
  8. 8. The conductive polymer prepared by the preparation method according to any one of claims 1-7, which is used for catalyzing 5-hydroxymethylfurfural to generate 2, 5-diformylfuran.

Description

Conductive polymer with TEMPO-containing side chain, and preparation method and application thereof Technical Field The invention relates to the technical field of electrochemistry, in particular to a conductive polymer with a side chain containing TEMPO, and a preparation method and application thereof. Background Along with the continuous consumption of fossil resources such as petroleum and the like, renewable biomass resources with rich reserves are developed and utilized to prepare bulk chemicals, fine chemicals and high polymer materials, and the shortage of petroleum resources is supplemented, so that the method has important significance. The biomass resource takes up the largest proportion of carbohydrate, and the 5-Hydroxymethylfurfural (HMF) with wide application market can be prepared by acid-catalyzed dehydration of fructose, glucose, cellulose and other carbohydrate. HMF is one of the biomass-based platform compounds, and is also an important intermediate for synthesizing various fine chemicals and furan-based polymers, and has received wide attention both at home and abroad. HMF oxidation produces a variety of important platform compounds such as 2, 5-Diformylfuran (DFF), 2, 5-furandicarboxylic acid (FDCA), 5-aldehyde-2-furancarboxylic acid (FFCA), and 5-hydroxymethylfuroic acid (HMFCA), with DFF, FDCA, and HMFCA being important downstream products from selective oxidation of HMF. The 2, 5-diformylfuran is one of the most important derivatives of 5-hydroxymethylfurfural, has wide application in the chemical industry field, and can be used for preparing pesticide intermediates, bactericides, heterocyclic compounds and the like. At present, the 2, 5-diformylfuran is prepared by oxidizing 5-hydroxymethylfurfural serving as a raw material by using metered oxidants such as manganese dioxide, chromium trioxide, sodium hypochlorite and the like, but the preparation method has serious environmental pollution, longer reaction time, larger consumption of the oxidants and reaction solvents, low product yield, difficult separation and unsuitable large-scale industrial production. For example, chinese patent CN101987839a discloses a method for preparing 2, 5-diformylfuran by oxidizing 5-hydroxymethylfurfural. Using Cu (NO 3)2 and VOSO 4 composite catalytic system, using molecular oxygen as oxygen source, heating to 80 ℃ in acetonitrile for reacting for 1.5h, the process is mild in reaction conditions and high in DFF yield, however, recovery and recycling of the catalyst of the system is difficult. 2, 6-Tetramethyl piperidine nitroxide radical (TEMPO) is formed into a resonance structure by the movement of contained single electron between nitroxides, so that the TEMPO is a nitroxide radical with high stability. TEMPO is widely used as a high-efficiency stable small-molecule catalyst for the selective oxidation of various hydroxyl functional groups. The TEMPO is used as a catalyst in the reaction for preparing the 2, 5-diformylfuran by using the 5-hydroxymethylfurfural as a raw material, has higher reaction yield, but is used as a homogeneous catalyst, and has the problems of difficult recovery and purification of a product and difficult separation of the catalyst and the product. Disclosure of Invention In the prior art, the preparation of 2, 5-diformylfuran by using 5-hydroxymethylfurfural as a raw material has the problem of difficult recovery of a catalyst and separation of the catalyst from a product. In order to solve the technical problems, the invention provides a conductive polymer with a TEMPO-containing side chain, and a preparation method and application thereof. According to the invention, a small molecular catalyst TEMPO is connected to the conductive polymer, and the heterogeneous electrochemical catalytic oxidation of 5-hydroxymethylfurfural by the TEMPO is realized to generate 2, 5-diformylfuran by the conductive polymer obtained through connection. The conductive polymer is used as a catalyst for preparing 2, 5-diformylfuran by electrocatalytic oxidation of 5-hydroxymethylfurfural, so that the problem of difficult separation of the catalyst and a product is avoided, and the conductive polymer has the characteristics of high reaction rate and high product yield. The specific technical scheme of the invention is as follows: in one aspect, the present invention provides a conductive polymer having TEMPO in its side chain, which has the structural formula shown below: wherein n=4 to 100, x=1 to 10, y=1 to 10. At present, in the process of preparing 2, 5-diformylfuran by using 5-hydroxymethyl furfural as a raw material, the used catalysts comprise sodium hypochlorite, TEMPO and the like, which are homogeneous catalysis, have the problem of difficult separation of the catalyst and a product, or other catalysts, such as a Cu (NO 3)2 and VOSO 4 composite catalysis system proposed by Chinese patent CN101987839A, also have the problem of difficult separation of the catalyst in a reaction solution.