Preparation method and application of a multi-metal oxide cluster electrocatalyst
By preparing (TBA)4H3[PW10Cu2O38(H2O)] foam electrocatalyst for the electrocatalytic synthesis of TBBS at room temperature and pressure, the problems of low catalytic efficiency and difficulty in catalyst recovery in traditional methods are solved, and a high-yield and environmentally friendly TBBS synthesis is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- LIAOCHENG UNIV
- Filing Date
- 2023-03-02
- Publication Date
- 2026-06-23
Smart Images
Figure CN116288467B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a (TBA)4H3[PW] 10 Cu2O 38 The preparation method of (H2O)] electrocatalyst belongs to the field of catalyst synthesis chemistry, and it is applied to the electrocatalytic synthesis of N-tert-butyl-2-benzothiazole sulfenamide at room temperature and atmospheric pressure. Background Technology
[0002] Polyoxometalates (POMs) are a class of nanoscale polyanionic clusters with unique structures and excellent acid-base and redox catalytic properties, making them a promising type of environmentally friendly catalyst. As an emerging molecular electrocatalyst, POMs can perform rapid and reversible stepwise electron transfer in electrochemical reactions, demonstrating great potential as green electrocatalysts.
[0003] N-tert-butyl-2-benzothiazole sulfenamide (TBBS) is a mercaptobenzothiazole sulfenamide derivative and a widely used rubber vulcanization accelerator. TBBS is a commonly used post-curing accelerator, possessing excellent scorch resistance and a short vulcanization time. When used in combination with small amounts of accelerators such as DPG and TMTD, it can provide a practical rubber vulcanization system with no scorch risk and rapid curing. This product is particularly suitable for synthetic rubber and high-alkalinity natural rubber, exhibiting slight discoloration, no blooming, and excellent aging resistance in vulcanized rubber. It is widely used in the production of industrial products such as cables, hoses, tires, and tapes. Therefore, the simple and efficient synthesis of TBBS has become a research hotspot. The main synthesis methods include: (1) using sodium hypochlorite as an oxidant and tert-butylamine and 2-thiol benzothiazole as a production process (Liu Yuanyuan, Research on a new process to improve the yield of accelerator TBBS, China Rubber, 2022, 1, 38); (2) the coupling oxidation reaction of TBBS prepared by hydrogen peroxide as an oxidant (Zhu Guoxu, Research on improving the yield of TBBS accelerator synthesized by hydrogen peroxide oxidation method, China Rubber, 2022, 6, 38); (3) copper-catalyzed aerobic cross-dehydrogenation coupling of 2-thiol benzothiazole and amine (H. Li, Ind. Eng. Chem. Res. 2021, 60, 14134-14142).
[0004] However, these traditional thermochemical catalytic strategies still have many drawbacks: (1) they require the addition of super-strong oxidants and generate a large amount of toxic waste; (2) they have low catalytic efficiency and are difficult to recover and reuse; (3) they require relatively high pressure and have complicated operating procedures. In 2021, the inventors applied for a method for preparing N-cyclohexyl-2-benzothiazole sulfenamide by oxygen method, which uses (TBA)4PW 11 Cu(H2O)O 39Foam catalysts are used in the oxygen-based synthesis of N-cyclohexyl-2-benzothiazole sulfenamide (Invention Patent: A method for preparing and applying a catalyst for the oxygen-based synthesis of N-cyclohexyl-2-benzothiazole sulfenamide; ZL201811337031.0). When using (TBA) 4PW... 11 Cu(H2O)O 39 When using foam catalysts for electrocatalytic synthesis of TBBS, the yield reaches 70%, but there is still room for improvement. This is because the current electrocatalyst has relatively few active sites, making the synthesis of multi-site polyoxometalate cluster electrocatalysts crucial. Furthermore, previous electrocatalysts were often applied to the electrode in a coated form, which resulted in problems such as small catalytic area, easy detachment from the electrode, and inability to be recycled (Z. Li, J. Mater. Chem. A. 2021, 9, 6152-6159). Based on the above literature, no reports have been published on the electrocatalytic synthesis of TBBS from polyoxometalates. Therefore, this invention patent provides a method for (TBA)4H3[PW 10 Cu2O 38 Preparation method of (H2O) foam electrocatalyst and its electrocatalytic synthesis of TBBS.
[0005] A search revealed no publicly available patent documents related to this invention application. Summary of the Invention
[0006] The purpose of this invention is to provide a simple, economical, and recyclable one-pot method (room temperature, ambient pressure) for the synthesis of N-tert-butyl-2-benzothiazole sulfenamide (TBA)4H3[PW 10 Cu2O 38 [H2O] electrocatalyst. This electrocatalyst has the advantages of easy operation, high yield, recyclable catalyst, and non-toxicity and pollution-free.
[0007] The solution of this invention is a method based on (TBA)4H3[PW 10 Cu2O 38 Electrochemical preparation method of TBBS in the presence of (H2O) foam catalyst.
[0008] The previously mentioned (TBA)4H3[PW 10 Cu2O 38 The preparation method of the (H2O)] electrocatalyst is as follows: Sodium alginate and water are added sequentially to a clean beaker and stirred to obtain a sodium alginate solution; (TBA)4H3[PW 10 Cu2O 38(H2O)] was dissolved in 5-10 mL of acetonitrile, and then added to an aqueous solution of sodium alginate; the mixture was stirred vigorously for a certain period of time, and the resulting solution was filled into a mold and then frozen in a refrigerator for 12 hours; finally, the excess water was removed by freeze drying in a freeze dryer to obtain a solid with the same shape as the mold; after the material was removed from the mold, (TBA)4H3[PW] was obtained with a diameter of approximately 5 cm. 10 Cu2O 38 (H2O)] electrocatalyst.
[0009] A method based on (TBA)4H3[PW 10 Cu2O 38 The preparation method of TBBS in the presence of (H2O) foam catalyst includes the following steps;
[0010] At room temperature and pressure, in a 500 mL glass jar, tetrabutylammonium tetrafluoroborate, dimercaptobenzothiazole, tert-butylamine, and (TBA)₄H₃[PW] were added. 10 Cu2O 38 (H2O)] foam catalyst and acetonitrile were added sequentially to the reaction flask; carbon plate anode (5 cm * 4 cm) and carbon plate cathode (5 cm * 4 cm) were inserted into the solution and fixed on an electrochemical workstation. The electrocatalytic reaction was carried out at 400 rpm and a constant current of 200 mA for 15 h at room temperature. Then the reaction was stopped, and the acetonitrile solvent was evaporated to dryness using a rotary evaporator. The product was concentrated and obtained by rapid column chromatography. After the reaction, (TBA)4H3[PW 10 Cu2O 38 The (H2O) foam catalyst, after being washed and dried, can be used for TBBS cycling experiments.
[0011] The molecular structure of TBBS is as follows:
[0012]
[0013] The proton and carbon NMR spectra of TBBS are as follows:
[0014] 1 H NMR (500 MHz, CDCl3) δ: 7.78 (dd, J = 10.9, 8.0 Hz, 2H), 7.38 (m,1H), 7.25 (d, J = 12.3 Hz, 1H), 3.41 (s, 1H), 1.28 (s, 9H). 13C NMR (125 MHz, CDCl3) δ: 155.1, 134.9, 125.8, 123.5, 121.5, 120.9, 55.6, 29.0.
[0015] This invention has unique advantages: the synthesis method of TBBS is simple, economical, environmentally friendly, and operated by electrocatalysis (at room temperature and pressure). The catalyst is inexpensive and the yield is high. Attached Figure Description
[0016] Figure 1 This is the 1H NMR spectrum of the compound TBBS.
[0017] Figure 2 This is the carbon NMR spectrum of the compound TBBS.
[0018] Figure 3 (TBA)4H3[PW 10 Cu2O 38 Infrared spectrum of (H2O) foam catalyst.
[0019] Figure 4 (TBA)4H3[PW 10 Cu2O 38 X-ray powder diffraction pattern of (H2O) foam catalyst.
[0020] Figure 5 (TBA)4H3[PW 10 Cu2O 38 X-ray photoelectron spectroscopy of (H2O) foam catalyst.
[0021] Figure 6 (TBA)4H3[PW 10 Cu2O 38 Scanning electron microscope image of (H2O) foam catalyst.
[0022] Figure 7 (TBA)4H3[PW 10 Cu2O 38 Mapping diagram of (H2O) foam catalyst. Detailed Implementation
[0023] The present invention will now be described in detail with reference to the embodiments, but the scope of protection is not limited thereto. Unless otherwise specified, the experimental methods in the following embodiments are conventional methods, and the materials and reagents used in the following embodiments are commercially available unless otherwise specified. Example 1:
[0024] (TBA)4H3[PW 10 Cu2O38 Preparation of (H2O)] electrocatalyst: Sodium alginate and water were added sequentially to a clean beaker and stirred to obtain a sodium alginate solution. (TBA)4H3[PW 10 Cu2O 38 (H₂O)₃ was dissolved in 10 mL of acetonitrile and then added to an aqueous solution of sodium alginate. The mixture was stirred vigorously for a certain period of time, and the resulting solution was filled into a mold and then frozen for 12 h. Finally, the solution was freeze-dried to remove excess moisture, yielding a solid with the same shape as the mold. After removing the material from the mold, (TBA)₄H₃[PW]₃ was obtained. 10 Cu2O 38 (H2O) Foam electrocatalyst. Example 2:
[0025] (TBA)4H3[PW 10 Cu2O 38 (H2O) Preparation of the electrocatalyst: Sodium alginate and water were added sequentially to a clean beaker and stirred to obtain a sodium alginate solution. (TBA)₄H₃[PW 10 Cu2O 38 (H2O) [The solution was dissolved in 8 mL of acetonitrile, and then added to an aqueous solution of sodium alginate. The mixture was stirred vigorously for a certain period of time, and the resulting solution was filled into a mold and then frozen for 12 hours. Finally, the solution was freeze-dried to remove excess moisture, yielding a solid with the same shape as the mold. After removing the material from the mold, (TBA)₄H₃[PW] was obtained. 10 Cu2O 38 (H2O)] foam electrocatalyst. Example 3:
[0026] (TBA)4H3[PW 10 Cu2O 38 Preparation of (H2O)] electrocatalyst: Sodium alginate and water were added sequentially to a clean beaker and stirred to obtain a sodium alginate solution. (TBA)4H3[PW 10 Cu2O 38 (H₂O)₃ was dissolved in 5 mL of acetonitrile and then added to an aqueous solution of sodium alginate. The mixture was stirred vigorously for a certain period of time, and the resulting solution was filled into a mold and then frozen for 12 h. Finally, the solution was freeze-dried to remove excess moisture, yielding a solid with the same shape as the mold. After removing the material from the mold, (TBA)₄H₃[PW]₃ was obtained. 10 Cu2O 38 (H2O)] foam electrocatalyst. Example 4:
[0027] (TBA)4H3[PW 10 Cu2O 38 Preparation of (H2O)] electrocatalyst: Sodium alginate and water were added sequentially to a clean beaker and stirred to obtain a sodium alginate solution. (TBA)4H3[PW 10 Cu2O 38 (H2O) was dissolved in a certain amount of acetonitrile, and then added to an aqueous solution of sodium alginate. The mixture was stirred vigorously for a certain period of time, and the resulting solution was filled into a mold and then frozen in a refrigerator for 6 hours. Finally, it was freeze-dried in a freeze dryer to remove excess moisture, yielding a solid with the same shape as the mold. After removing the material from the mold, (TBA)4H3[PW 10 Cu2O 38 (H2O)] foam electrocatalyst. Example 5:
[0028] At room temperature and pressure, in a 500 mL glass jar, tetrabutylammonium tetrafluoroborate (0.5 mol), dimercaptobenzothiazole (0.6 mol), tert-butylamine (1.8 mol), and (TBA)4H3[PW] were added. 10 Cu2O 38 The (H₂O) electrocatalyst (600 mg) and acetonitrile (300 mL) were added sequentially to the reaction flask. A carbon plate anode (5 cm * 4 cm) and a carbon plate cathode (5 cm * 4 cm) were inserted into the solution and fixed on an electrochemical workstation. The electrocatalytic reaction was carried out at room temperature and a constant current of 200 mA at a rate of 400 rpm for 10 h. The reaction was then stopped, and the acetonitrile solvent was evaporated to dryness using a rotary evaporator. The product was concentrated and obtained by rapid column chromatography in 90% yield. Example 6:
[0029] At room temperature and pressure, in a 500 mL glass jar, tetrabutylammonium tetrafluoroborate (0.5 mol), dimercaptobenzothiazole (0.6 mol), tert-butylamine (1.8 mol), and (TBA)4H3[PW] were added. 10 Cu2O 38The (H₂O) electrocatalyst (800 mg) and acetonitrile (300 mL) were added sequentially to the reaction flask. A carbon plate anode (5 cm * 4 cm) and a carbon plate cathode (5 cm * 4 cm) were inserted into the solution and fixed on an electrochemical workstation. The electrocatalytic reaction was carried out at room temperature and a constant current of 200 mA at a rate of 400 rpm for 10 h. The reaction was then stopped, and the acetonitrile solvent was evaporated to dryness using a rotary evaporator. The product was concentrated and obtained by rapid column chromatography in 89% yield. Example 7:
[0030] At room temperature and pressure, in a 500 mL glass jar, tetrabutylammonium tetrafluoroborate (0.5 mol), dimercaptobenzothiazole (0.6 mol), tert-butylamine (1.8 mol), and (TBA)4H3[PW] were added. 10 Cu2O 38 The (H₂O) electrocatalyst (400 mg) and acetonitrile (300 mL) were added sequentially to the reaction flask. A carbon plate anode (5 cm * 4 cm) and a carbon plate cathode (5 cm * 4 cm) were inserted into the solution and fixed on an electrochemical workstation. The electrocatalytic reaction was carried out at room temperature and a constant current of 200 mA at a rate of 400 rpm for 10 h. The reaction was then stopped, and the acetonitrile solvent was evaporated to dryness using a rotary evaporator. The product was concentrated and obtained by rapid column chromatography in 83% yield. Example 8:
[0031] At room temperature and pressure, in a 500 mL glass jar, tetrabutylammonium tetrafluoroborate (0.5 mol), dimercaptobenzothiazole (0.6 mol), tert-butylamine (1.8 mol), and (TBA)4H[PW] were added. 11 CuO 39 (H₂O) foam catalyst (600 mg) and acetonitrile (300 mL) were added sequentially to the reaction flask. A carbon plate anode (5 cm * 4 cm) and a carbon plate cathode (5 cm * 4 cm) were inserted into the solution and fixed on an electrochemical workstation. The electrocatalytic reaction was carried out at room temperature and a constant current of 200 mA at a rate of 400 rpm for 8 h. The reaction was then stopped, and the acetonitrile solvent was evaporated to dryness using a rotary evaporator. The product was concentrated and obtained by rapid column chromatography in 80% yield.
[0032] Comparative Example 1:
[0033] At room temperature and pressure, in a 500 mL glass jar, tetrabutylammonium tetrafluoroborate (0.5 mol), dimercaptobenzothiazole (0.6 mol), tert-butylamine (1.8 mol), and (TBA)4H3[PW] were added.10 Cu2O 38 The (H₂O) electrocatalyst (200 mg) and acetonitrile (300 mL) were added sequentially to the reaction flask. A carbon plate anode (5 cm * 4 cm) and a carbon plate cathode (5 cm * 4 cm) were inserted into the solution and fixed on an electrochemical workstation. The electrocatalytic reaction was carried out at room temperature and a constant current of 200 mA at a rate of 400 rpm for 10 h. The reaction was then stopped, and the acetonitrile solvent was evaporated to dryness using a rotary evaporator. The product was concentrated and obtained by rapid column chromatography in 56% yield.
[0034] Comparative Example 2:
[0035] Without adding a catalyst, tetrabutylammonium tetrafluoroborate (0.5 mol), dimercaptobenzothiazole (0.6 mol), tert-butylamine (1.8 mol), and acetonitrile (300 mL) were sequentially added to a reaction flask in a 500 mL glass container. A carbon plate anode (5 cm * 4 cm) and a carbon plate cathode (5 cm * 4 cm) were inserted into the solution and fixed on an electrochemical workstation. The electrocatalytic reaction was carried out at room temperature and a constant current of 200 mA at a rate of 400 rpm for 8 h. The reaction was then stopped, and the acetonitrile solvent was evaporated to dryness using a rotary evaporator. The product was concentrated and obtained by rapid column chromatography in 10% yield.
[0036] The synthesis of TBBS is a coupling reaction, and the selection of the reactant ratio and catalyst dosage is crucial. After repeated experiments, the catalyst chosen was (TBA)₄H₃[PW 10 Cu2O 38 The electrocatalyst (H2O) was reacted under the following conditions: the mass ratio of dimercaptobenzothiazole:cyclohexylamine:electrocatalyst was 8.4~10.0:13.0~15.6:0.4~0.9. The optimal reaction conditions were 10 h of electrocatalysis at room temperature and pressure.
[0037] When the amount of electrocatalyst is insufficient or not used, the yield decreases significantly. When no electrocatalyst is used, the yield is only 10%, and when the amount of electrocatalyst is 200 mg, the yield is only 56%. This indicates that the catalyst can activate the substrate in the synthesis of TBBS, enabling better electrochemical synergy between substrate molecules, and ultimately producing the target product.
Claims
1. A (TBA)4H3[PW 10 Cu2O 38 The method for preparing the (H2O)] electrocatalyst is characterized by, The steps are as follows: Add sodium alginate and water to a container in sequence, stir well to obtain a sodium alginate solution; then add (TBA)4H3[PW 10 Cu2O 38 (H2O)] was dissolved in acetonitrile, and then added to an aqueous solution of sodium alginate; the mixture was stirred vigorously for a certain period of time, and the resulting solution was filled into a mold and then frozen in a refrigerator for 12 hours; finally, the excess water was removed by freeze-drying to obtain a solid with the same shape as the mold; after the material was removed from the mold, (TBA)4H3[PW 10 Cu2O 38 (H2O)] electrocatalyst.
2. The preparation method according to claim 1, characterized in that, (TBA)4H3[PW 10 Cu2O 38 The mass ratio of (H2O) to acetonitrile to sodium alginate to H2O is 0.5~2:3~6:1~5:80~150.
3. The preparation method according to claim 2, characterized in that, (TBA)4H3[PW 10 Cu2O 38 The mass ratio of (H2O) to acetonitrile to sodium alginate to H2O is 1.2:4:3:
120.
4. The preparation method according to claim 1, characterized in that, Vigorous stirring time is 50~100 min.
5. The preparation method according to claim 4, characterized in that, The vigorous stirring time is 70 minutes.
6. The preparation method according to claim 1, characterized in that, The freeze-drying time is 40 h to 72 h.
7. The preparation method according to claim 6, characterized in that, The freeze-drying time is 40 hours.
8. (TBA)4H3[PW] prepared by any one of the preparation methods described in claims 1-7 10 Cu2O 38 Use of (H2O)] electrocatalyst in the preparation of N-tert-butyl-2-benzothiazole sulfenamide.
9. The use as described in claim 8, characterized in that, (TBA)4H3[PW 10 Cu2O 38 The preparation method of N-tert-butyl-2-benzothiazole sulfenamide in the presence of (H2O)] electrocatalyst is as follows: First, under normal temperature and pressure, tetrabutylammonium tetrafluoroborate, dimercaptobenzothiazole, tert-butylamine, and (TBA)4H3[PW 10 Cu2O 38 [H2O] The electrocatalyst and acetonitrile were added sequentially to the reaction flask; the carbon plate anode and carbon plate cathode were inserted into the solution and equipped with an electrochemical workstation. The reaction was electrolyzed at a constant current of 200 mA at a rate of 400 rpm for 10 h at room temperature; then the reaction was stopped, and the acetonitrile solvent was evaporated to dryness using a rotary evaporator and concentrated to obtain the crude product; the product was obtained by rapid column chromatography on a silica gel column using a petroleum ether:ethyl acetate = 15:1, v:v.
10. The use as described in claim 9, characterized in that, The mass ratio of dimercaptobenzothiazole:cyclohexylamine:electrocatalyst is 8.4~10.0:13.0~15.6:0.4~0.9.