New method for olefin epoxidation and resource conversion driven by commercial carbon-based material

Abstract

The invention aims to provide a novel olefin epoxidation and resource conversion method driven by a commercial carbon-based material, belongs to the technical field of electro-catalysis energy conversion, and can be applied to olefin epoxidation and further resource utilization of epoxy compounds. According to the invention, the commercial carbon-based material is used as an electrode material to efficiently electrocatalyze olefin to generate an epoxy compound, the conversion rate and selectivity are high, and the electrode has good stability, can be repeatedly used to maintain high efficiency, and can be used as an electrocatalytic material for high-performance electrocatalytic epoxidation; efficient seawater resource utilization can be realized through a large amount of Cl <-> and Br <-> mediated reaction in seawater; the epoxy compound can be further subjected to electro-catalysis to generate a diol compound, and the reaction is carried out in pure water without adding other substances; a commercialized carbon-based material is used as an electrode to catalyze epoxidation and resource conversion of olefin, the reaction condition is simple, the cost is low, and the method is green and environment-friendly, so that commercialized application becomes possible.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrocatalytic energy conversion, and specifically relates to a new method for olefin epoxidation and resource conversion driven by commercial carbon-based materials. Background Art

[0002] Seawater accounts for about 71% of the earth's surface and has huge development potential. Taking seawater resources as an example, the utilization of seawater water resources and seawater chemical resources has a very broad prospect. Seawater resource development or seawater comprehensive utilization technology includes direct use of seawater, seawater desalination and extraction of chemical resources in seawater.

[0003] As an important class of organic synthesis intermediates, epoxy compounds are widely used in the fields of petrochemicals, fine chemicals and organic synthesis, and occupy an important position in the national economy. For example, ethylene oxide and propylene oxide are raw materials for the synthesis of epoxy resins and chlorohydrin rubbers, among which epoxy resins are widely used due to their excellent performance. Olefin epoxidation is an important way to synthesize epoxy compounds and occupies an important position in organic synthesis. Due to the polarization of charge in the epoxy group and the existence of tension in the epoxy group, the epoxy group has high reactivity and can synthesize a variety of required substances through selective ring opening (especially the formation of diol compounds) or functional group conversion; at the same time, the epoxy group is also easy to react with groups containing active hydrogen atoms, such as amines, phenolic hydroxyl groups, carboxyl groups, hydroxyl groups, amides, etc. The main direction of olefin epoxidation technology is to screen and design synthetic techniques and catalytic reaction systems with excellent performance and relatively simple operation. At present, there are two main methods for the industrial production of epoxy compounds: the halohydrin method is widely used because of its simple technology, but there are many synthetic steps in the production process, more by-products, and serious equipment corrosion; the co-oxidation method also produces by-products with low economic benefits and low atomic utilization of the reaction. Both of these traditional methods for producing epoxy compounds have certain defects, so it is of great value to develop an environmentally friendly, high-atomic-utilization, and low-energy-consumption method for producing epoxy compounds.

[0004] Diol compounds are a class of organic compounds containing two hydroxyl groups, which are widely used in chemistry, medicine, materials science and other fields. Studies have shown that some diol compounds have good application prospects as plasticizers, solvents, stabilizers, etc. in polymers and their composites; diol compounds are used as intermediates in drug synthesis, especially in the synthesis of antibiotics and other bioactive molecules. The application is growing; some diol compounds are widely used in cosmetics due to their moisturizing and solvent properties. At present, many traditional chemical synthesis methods often involve organic solvents and high energy consumption, which may cause environmental pollution. Some synthetic routes may produce a large number of by-products, which not only increases the difficulty of separation and purification, but also increases the production cost. Therefore, it is of great value to develop an environmentally friendly and simple method for producing diol compounds. Summary of the invention

[0005] The purpose of the present invention is to provide a new method for olefin epoxidation and resource conversion driven by commercial carbon-based materials to solve the current problems of low efficiency, high energy consumption and environmental pollution in olefin epoxidation and epoxy ring-opening to diols.

[0006] The present invention adopts the following technical solution: A new method for olefin epoxidation and resource conversion driven by commercial carbon-based materials, using commercial carbon-based materials as working electrodes for electrocatalysis.

[0007] Furthermore, the commercial carbon-based material includes any one of carbon paper, carbon cloth, graphite felt, and graphite sheet.

[0008] Furthermore, the carbon content of the commercial carbon-based material is greater than 99%.

[0009] Further, the method comprises Cl - / Br - Mediates the formation of epoxides.

[0010] Furthermore, the epoxy compound can be further converted into a diol compound.

[0011] A new method for olefin epoxidation and resource conversion driven by commercial carbon-based materials, comprising the following steps: S1. Mix acetonitrile and water, add Cl - or Br - , stirring evenly to obtain a mixed solution; S2, adding substrate olefin to the mixed solution of S1, inserting electrodes, and reacting under constant current; S3, extracting and purifying the solution obtained after the reaction in S2 to obtain an epoxy compound; S4. Add the purified epoxy compound into water and react under constant potential to obtain a diol compound.

[0012] Further, in step S1, - or Br - Derived from NaCl or NaBr powder.

[0013] Furthermore, the volume ratio of acetonitrile to water in step S1 is 1:1-4:1.

[0014] Furthermore, the Cl - or Br - The amount added is more than 0.5 times the molar amount of olefin.

[0015] Furthermore, the extraction in step S3 refers to the use of a water-insoluble organic solvent to separate the water in the electrolyte and the salt therein, so as to facilitate the next step of purification.

[0016] Furthermore, the purification in step S3 refers to separating the epoxy compound from other impurities using thin layer chromatography.

[0017] A new method of olefin epoxidation and resource conversion driven by commercial carbon-based materials is applied to the resource utilization of seawater.

[0018] The beneficial effects of the present invention are as follows: 1. This invention successfully uses commercial carbon-based materials to drive olefin epoxidation under the mediation of seawater, providing a sustainable solution for efficient seawater resource utilization and comprehensive utilization. In the process of electrocatalytic epoxidation, due to its good conductivity and unique structure, it can quickly oxidize Cl in seawater. - Br - , it can efficiently utilize seawater resources and has good stability under long-term repeated experiments, and it is expected to become a high-performance electrocatalytic material for commercial applications; 2. The epoxidation method driven by commercial carbon-based materials under the mediation of seawater provided by the present invention utilizes renewable electric energy to drive the electrochemical epoxidation reaction in the epoxidation of olefins, providing a green way for the production of epoxy compounds, with high atomic utilization and low energy consumption, and can realize the commercial application of electrocatalytic epoxidation; 3. After the epoxy compound is generated, the present invention can further utilize commercial carbon-based materials to electrocatalytically open the epoxy compound to form a diol compound. This process can occur in pure water without any additives. The process is simple, low-cost, and green and environmentally friendly, and can realize the commercial application of electrocatalytic epoxy ring opening to diol compounds. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a scanning electron microscope image of the graphite felt in Example 1 of the present invention, and Figures a, b, c, and d are scanning electron microscope images of 2 μm, 5 μm, 10 μm, and 20 μm respectively; Figure 2 This is an X-ray diffraction (XRD) characterization test result diagram of the graphite felt in Example 2 of the present invention; Figure 3 is the hydrogen spectrum of the epoxy compound prepared in Example 3 of the present invention; Figure 4 is the carbon spectrum of the epoxy compound prepared in Example 3 of the present invention; Figure 5 The hydrogen spectrum of the epoxy compound prepared in Example 4 of the present invention is Figure 6 is the carbon spectrum of the epoxy compound prepared in Example 4 of the present invention; Figure 7 is the hydrogen spectrum of the epoxy compound prepared in Example 5 of the present invention; Figure 8 is the carbon spectrum of the epoxy compound prepared in Example 5 of the present invention; Fig. 9 is the hydrogen spectrum of the epoxy compound prepared in Example 6 of the present invention; Fig.10 is the carbon spectrum of the epoxy compound prepared in Example 6 of the present invention; Fig.11 is the hydrogen spectrum of the epoxy compound prepared in Example 7 of the present invention; Fig.12 is the carbon spectrum of the epoxy compound prepared in Example 7 of the present invention; Fig.13 This is the hydrogen spectrum of the diol compound prepared in Example 8 of the present invention; Fig.14 This is the carbon spectrum of the diol compound prepared in Example 8 of the present invention; Fig.15 This is the hydrogen spectrum of the diol compound prepared in Example 9 of the present invention; Fig.16 This is the carbon spectrum of the diol compound prepared in Example 9 of the present invention; Fig.17 This is the hydrogen spectrum of the diol compound prepared in Example 10 of the present invention; Fig.18 This is the carbon spectrum of the diol compound prepared in Example 10 of the present invention; Fig.19 This is the hydrogen spectrum of the diol compound prepared in Example 11 of the present invention; Fig. 20 This is the carbon spectrum of the diol compound prepared in Example 11 of the present invention; Fig.21 This is the hydrogen spectrum of the diol compound prepared in Example 12 of the present invention; Fig. 22 This is the carbon spectrum of the diol compound prepared in Example 12 of the present invention; Fig.23 This is a graph showing the yield of epoxy compounds obtained from repeated experiments using graphite felt as a working electrode in Example 3 of the present invention; Fig.24 It is a specific implementation diagram of the present invention. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0021] In order to make the purpose, technical scheme and advantages of the present application clearer, more thorough and more complete, the technical scheme of the present invention is clearly and completely described below through the accompanying drawings and examples. The following detailed descriptions are all descriptions of the embodiments, and are intended to provide further detailed descriptions of the present invention. Unless otherwise specified, all technical terms used in the present invention have the same meaning as those generally understood by those skilled in the art to which the present application belongs.

[0022] The instruments, equipment, reagents and materials used in the examples were obtained through commercial channels, and the composition information of the reagents used is shown in Table 1.

[0023] Table 1 Reagent composition information Example 1 The commercial carbon-based material graphite felt used in the experiment was observed by scanning electron microscopy (SEM). The results are as follows: Figure 1 As shown in Figure 1, the surface of graphite felt presents a fibrous structure. The fiber network of graphite felt can be observed under a scanning electron microscope. These fibers usually have a large porosity and form an interlaced network structure.

[0024] Example 2 The commercial carbon-based material graphite felt used in the experiment was subjected to X-ray diffraction (XRD) characterization test, and the results are as follows: Figure 2 As shown, graphite felt usually shows the (002) diffraction peak of graphite, usually at about 26° (2θ). This is a characteristic peak of the inter-layer spacing of graphite.

[0025] Example 3 Br - The electrocatalytic epoxidation method using graphite felt as an electrode is mediated, and the specific steps are as follows: Weigh 206 mg of NaBr and add it to a mixed solution of 30 ml of CH3CN and 10 ml of H2O. Stir well and then add 1 mmol of styrene. Cut a 2cm×2.5cm graphite felt and clamp it with a platinum electrode clamp as the working electrode, the carbon rod as the counter electrode, and the Ag / AgCl electrode as the reference electrode. Perform constant current polarization at an external current of 30mA for 3h to obtain Br - mediated epoxy compounds.

[0026] The hydrogen and carbon spectra of the epoxy compounds obtained are as follows: Figure 3 and Figure 4 As shown, it is consistent with the standard H NMR spectrum.

[0027] The graphite felt was used as the working electrode and the experiment was repeated 5 times. The yield of the corresponding epoxy compound was as follows: Fig.23 shown.

[0028] Example 4 The olefin in Example 3 was changed to 4-chlorostyrene, and the added amount was 1 mmol. The rest of the operations were the same as in Example 3.

[0029] The hydrogen and carbon spectra of the epoxy compounds obtained are as follows: Figure 5 and Figure 6 As shown, it is consistent with the standard H NMR spectrum.

[0030] Example 5 The olefin in Example 3 was changed to 4-vinylbiphenyl, and the added amount was 1 mmol. The rest of the operation was the same as in Example 3.

[0031] The hydrogen and carbon spectra of the epoxy compounds obtained are as follows: Figure 7 and Figure 8 As shown, it is consistent with the standard H NMR spectrum.

[0032] Example 6 The olefin in Example 3 was changed to (2,3-epoxypropyl)benzene, and the added amount was 1 mmol. The remaining operations were the same as in Example 3.

[0033] The hydrogen and carbon spectra of the epoxy compounds obtained are as follows: Fig. 9 and Fig.10 As shown, it is consistent with the standard H NMR spectrum.

[0034] Example 7 The olefin in Example 3 was changed to β-methylstyrene, and the added amount was 1 mmol. The remaining operations were the same as in Example 3.

[0035] The hydrogen and carbon spectra of the epoxy compounds obtained are as follows: Fig.11 and Fig.12 As shown, it is consistent with the standard H NMR spectrum.

[0036] Example 8 The epoxy compound prepared in Example 3 was purified by thin layer chromatography, and the purified epoxy compound was added to 24 ml of H2O.

[0037] Cut a 2cm×2.5cm graphite felt, clamp it with a platinum electrode clamp as the working electrode, the carbon rod as the counter electrode, and the Ag / AgCl electrode as the reference electrode. Perform constant potential polarization at an external voltage of 1V for 6 hours to open the epoxy compound into a diol compound.

[0038] The hydrogen and carbon spectra of the obtained diol compound are as follows Fig.13 and Fig.14 As shown, it is consistent with the standard H NMR spectrum.

[0039] Example 9 The epoxy compound prepared in Example 4 was purified by thin layer chromatography, and the purified epoxy compound was added to 24 ml of H2O.

[0040] Cut a 2cm×2.5cm graphite felt, clamp it with a platinum electrode clamp as the working electrode, the carbon rod as the counter electrode, and the Ag / AgCl electrode as the reference electrode. Perform constant potential polarization at an external voltage of 1V for 6 hours to open the epoxy compound into a diol compound.

[0041] The hydrogen and carbon spectra of the obtained diol compound are as follows Fig.15 and Fig.16 As shown, it is consistent with the standard H NMR spectrum.

[0042] Example 10 The epoxide prepared from 4-bromostyrene was purified by thin layer chromatography and the purified epoxide was added to 24 ml of H2O.

[0043] Cut a 2cm×2.5cm graphite felt, clamp it with a platinum electrode clamp as the working electrode, the carbon rod as the counter electrode, and the Ag / AgCl electrode as the reference electrode. Perform constant potential polarization at an external voltage of 1V for 6 hours to open the epoxy compound into a diol compound.

[0044] The hydrogen and carbon spectra of the obtained diol compound are as follows Fig.17 and Fig.18 As shown, it is consistent with the standard H NMR spectrum.

[0045] Embodiment 11 The epoxy compound prepared using stilbene was purified by thin layer chromatography and the purified epoxy compound was added to 24 ml of H2O.

[0046] Cut a 2cm×2.5cm graphite felt, clamp it with a platinum electrode clamp as the working electrode, the carbon rod as the counter electrode, and the Ag / AgCl electrode as the reference electrode. Perform constant potential polarization at an external voltage of 1V for 6 hours to open the epoxy compound into a diol compound.

[0047] The hydrogen and carbon spectra of the obtained diol compound are as follows Fig.19 and Fig. 20 As shown, it is consistent with the standard H NMR spectrum.

[0048] Example 12 The epoxy compound prepared using α-methylstyrene was purified by thin layer chromatography and the purified epoxy compound was added to 24 ml of H2O.

[0049] Cut a 2cm×2.5cm graphite felt, clamp it with a platinum electrode clamp as the working electrode, the carbon rod as the counter electrode, and the Ag / AgCl electrode as the reference electrode. Perform constant potential polarization at an external voltage of 1V for 6 hours to open the epoxy compound into a diol compound.

[0050] The hydrogen and carbon spectra of the obtained diol compound are as follows Fig.21 and Fig. 22 As shown, it is consistent with the standard H NMR spectrum.

[0051] Embodiment 13 Cl - The electrocatalytic epoxidation method using graphite felt as an electrode is mediated. The specific steps are as follows: The specific steps are exactly the same as those in Example 3, except that 206 mg of NaBr is replaced by 117 mg of NaCl to obtain Cl - mediated epoxy compounds.

[0052] Embodiment 14 Electrocatalytic synthesis of epoxy compounds under seawater mediation: the volume ratios of acetonitrile and seawater were 3:1 and 1:1 respectively, the seawater was from the South my country Sea, East China Sea, Yellow Sea and Bohai Sea, the amounts of seawater used were 10 ml (volume ratio 3:1) and 20 ml (volume ratio 1:1) respectively, graphite felt was used as electrode, the olefin used was styrene, and the yields of epoxy compounds obtained are shown in Table 2.

[0053] Table 2 Results of electrocatalytic synthesis of epoxy compounds mediated by seawater As can be seen from Table 2, the present invention can successfully electrocatalyze the synthesis of epoxy compounds under the mediation of seawater.

[0054] Embodiment 15 Using other commercial carbon-based materials, the experimental steps were the same as in Example 3, and the results of the obtained epoxy compounds and diol compounds are shown in Table 3.

[0055] Table 3 Results of epoxy compounds and diol compounds obtained from other commercial carbon-based materials The present invention successfully invented a new method for olefin epoxidation and resource conversion driven by commercial carbon-based materials, which provides a sustainable solution for efficient seawater resource utilization and comprehensive utilization. In the process of electrocatalytic epoxidation, due to its good conductivity and unique structure, Cl in seawater can be quickly oxidized. - Br -, efficiently utilize seawater resources, and have good stability under long-term repeated experiments, and can be used as a high-performance electrocatalytic material with potential for commercial application; in the epoxidation of olefins, the use of renewable electricity to drive the electrochemical epoxidation reaction provides a green way for the production of epoxy compounds, and has high atomic utilization and low energy consumption, which can realize the commercial application of electrocatalytic epoxidation; after the epoxide is generated, commercial carbon-based materials can be further used to electrocatalyze the ring-opening of the epoxide to form a diol compound. This process can occur in pure water without any additives. The process is simple, low-cost, and green and environmentally friendly, which can realize the commercial application of electrocatalytic epoxide ring-opening.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A new method for olefin epoxidation and resource conversion driven by commercial carbon-based materials, characterized in that: The method uses commercial carbon-based materials as working electrodes for electrocatalysis.

2. The novel method for olefin epoxidation and resource conversion driven by commercial carbon-based materials according to claim 1, characterized in that: The commercial carbon-based material includes any one of carbon paper, carbon cloth, graphite felt, and graphite sheet, and the carbon content of the commercial carbon-based material is greater than 99%.

3. The novel method for olefin epoxidation and resource conversion driven by commercial carbon-based materials according to claim 1, characterized in that: The method is carried out by Cl - / Br - Mediates the formation of epoxides.

4. The novel method for olefin epoxidation and resource conversion driven by commercial carbon-based materials according to claim 3 is characterized in that: The epoxy compound can be further converted into a diol compound.

5. A novel method for olefin epoxidation and resource conversion driven by commercial carbon-based materials as claimed in any one of claims 1 to 4, characterized in that: The steps include: S1. Mix acetonitrile and water, add Cl - or Br - , stirring evenly to obtain a mixed solution; S2, adding substrate olefin to the mixed solution of S1, inserting electrodes, and reacting under constant current; S3, extracting and purifying the solution obtained after the reaction in S2 to obtain an epoxy compound; S4. Add the purified epoxy compound into water and react under constant potential to obtain a diol compound.

6. The novel method for olefin epoxidation and resource conversion driven by commercial carbon-based materials according to claim 5, characterized in that: The Cl in step S1 - or Br - Derived from NaCl or NaBr powder.

7. The novel method of olefin epoxidation and resource conversion driven by commercial carbon-based materials according to claim 5, characterized in that: The volume ratio of acetonitrile to water is 1:1-4:1; the Cl - or Br - The amount added is more than 0.5 times the molar amount of olefin.

8. The novel method of olefin epoxidation and resource conversion driven by commercial carbon-based materials according to claim 5, characterized in that: Extraction in step S3 refers to the use of a water-insoluble organic solvent to separate the water in the electrolyte from the salt therein, so as to facilitate the next step of purification.

9. The novel method of olefin epoxidation and resource conversion driven by commercial carbon-based materials according to claim 5, characterized in that: The purification in step S3 refers to separating the epoxy compound from other impurities using thin layer chromatography.

10. A new method for olefin epoxidation and resource conversion driven by commercial carbon-based materials as described in any one of claims 1 to 4, applied to the resource utilization of seawater.

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