An LDH electrocatalyst in sp 2 Application of C-H activation with selective mono / dicarboxylation of CO2

Abstract

A layered double hydroxide (LDH) in a heterogeneous electrocatalytic sp 2 Application of C–H activation and CO2 carboxylation. The preparation method of a cobalt-iron molybdate intercalated hydrotalcite (CoFe-Mo LDH) catalyst is as follows: the CoFe-Mo LDH is prepared by a simple coprecipitation method. The CoFe-Mo LDH is used for a heterogeneous electrocatalytic sp 2 C–H activation and CO2 carboxylation. By changing the CoFe-Mo LDH intercalation of the CoFe-Mo LDH solvent environment, a series of mono-carboxylation and di-carboxylation products can be obtained, such as: in the case of benzene as a substrate and DMF as a solvent, a mono-carboxylation product benzoic acid is obtained; in the case of benzene as a substrate and MeCN as a solvent, a di-carboxylation product isophthalic acid is obtained. For the first time, the on-demand switching of the mono-carboxylation and di-carboxylation of phenyl substrates is realized, and this research not only provides a new heterogeneous electrocatalytic strategy to achieve the carbon neutralization target, but also successfully converts cheap and easily available chemicals into high-value and carbon chain growth carboxylic acids under mild conditions.

Description

Technical Field

[0001] An LDH electrocatalyst in sp 2 Applications of CH activation and selective mono / dicarboxylation of CO2. Background Technology

[0002] The excessive consumption of fossil fuels has led to a rise in global carbon dioxide levels, which has become a major cause of the global greenhouse effect. However, everything has two sides; CO2 can also be considered a usable, abundant, and renewable C1 resource. Therefore, the conversion of CO2 into valuable chemicals has attracted considerable interest. Besides the widely studied reduction of CO2 to various chemical products such as formic acid, carbon monoxide, formamide, methanol, and methylamine, catalytic carboxylation using CO2 as a carbon source to produce value-added fine chemicals may be a more promising option for achieving sustainable development. After nearly a decade of continuous effort, it is now possible to electrocatalytically activate C-halogen bonds and unsaturated olefins (sp...) 2 CH bond, aromatic ring sp 2 CH bonds and inert sp bonds 2 CH bonds are used to produce fine chemicals via CO2 carboxylation. To date, electrocatalytic sp... 2 CH activation and CO2 carboxylation are mainly limited to homogeneous catalytic systems. Achieving sp in heterogeneous photocatalytic systems... 2 CH activation and CO2 utilization to produce valuable carboxylic acids remain a highly challenging and attractive goal.

[0003] Heterogeneous electrocatalysis offers numerous advantages, including ease of separation, low cost, and low pollution, making it an efficient and promising approach for novel organic transformations. To date, several heterogeneous electrocatalytic reactions have been investigated to achieve the efficient synthesis of valuable chemicals. Considering the limitations of traditional oxidation processes... 2 The dependence of CH activation on a large number of expensive and dangerous oxidants affects sp. 2 The sustainability of CH activation. Electrocatalysis provides a means to achieve sp under mild conditions. 2 A promising approach to CH activation.

[0004] MoO4 2- Intercalated CoFe hydrotalcite, as a novel type of tunable electrocatalytic material, possesses excellent electronic structure tuning capabilities, good electrochemical stability, and electrical conductivity. MoO4 2- The introduction of this technology not only expands the interlayer spacing and improves ion migration and reactant accessibility, but also effectively regulates the electron density of the Co / Fe metal centers, enhancing charge separation and transport efficiency, thereby improving the activation capacity of CO2 and the aromatic ring sp. 2The directional functionalization efficiency of C–H bonds is enhanced. Furthermore, this intercalation structure can form differentiated coordination states under different solvent environments, enabling precise control of the reaction pathway and exhibiting high activity, high selectivity, and broad substrate adaptability. With its excellent structural stability, designability, and green electrocatalytic properties, MoO4… 2- Intercalated CoFe hydrotalcite shows significant potential as a high-performance electrocatalyst. Summary of the Invention

[0005] An application of an LDH electrocatalyst in sp2 CH activation and selective mono / dicarboxylation of CO2, characterized in that: when DMF is used as a solvent, it performs monocarboxylation of aromatic hydrocarbons, and when MeCN is used as a solvent, it performs dicarboxylation of aromatic hydrocarbons.

[0006] CoFe-C LDH, a carbonate-intercalated cobalt-iron hydrotalcite, was synthesized in one step via a coprecipitation method. Co(NO3)2•6H2O and Fe(NO3)3•9H2O (cobalt / iron molar ratio = 3:1) were dissolved in H2O to prepare a 0.6 M solution A. Separately, 0.4 g NaOH (10 mmol) and 2.1 g Na2CO3 (20 mmol) were dissolved in H2O with stirring to obtain solution B. Solutions A and B were simultaneously and slowly added dropwise to a three-necked flask containing 5 mL of H2O under stirring in a 60 °C water bath. The pH of the system was adjusted to 9.0, and the reaction was continued with stirring for 0.5 h. The resulting suspension was then transferred to a PTFE-lined stainless steel reactor and subjected to hydrothermal reaction at 80 °C for 48 h. After cooling to room temperature, the precipitate was collected by centrifugation, thoroughly washed with deionized H₂O and EtOH, and finally dried at 60 °C to obtain CoFe-C LDH. For comparison, NiFe-C LDH and NiCo-C LDH were synthesized using the exact same experimental procedure, with only the crystallization conditions adjusted: NiFe-C was crystallized at pH 8.5 and 120 °C, while NiCo-C was prepared at pH 9 and 80 °C.

[0007] A one-step cobalt-iron hydrotalcite (CoFe-Mo LDH) intercalated with molybdate was synthesized using a co-precipitation method. Deionized water was bubbled with nitrogen for 30 min to remove CO2. The entire experiment was conducted under nitrogen protection. First, Co(NO3)2•6H2O and Fe(NO3)3•9H2O with a Co / Fe molar ratio of 3:1 were dissolved in deionized water to form a 0.6 M salt solution A. Then, 10 mL of sodium molybdate aqueous solution was prepared, n(MoO4) 2- ): n(Fe 3+The ratio of A to B was 2:1, and the pH was adjusted to 9-9.5 with 0.5M NaOH to obtain solution B. Solution A and solution B were simultaneously added dropwise to a three-necked flask containing a small amount of deionized water and stirred vigorously in a 60℃ water bath. The resulting slurry was placed in a hydrothermal reactor and heated at 80℃ for 48 h. Then, it was thoroughly washed by centrifugation with deionized water and ethanol, and finally dried at 60℃ overnight to obtain the CoFe-Mo LDH sample.

[0008] Aromatics sp 2 Preparation of monoacid products with increased carbon chains by CH activation and CO2 carboxylation: In a CO2 atmosphere at 1 atm, 15 mg of catalyst, 0.5 mmol of substrate, 1 mmol of N-Bu4NPF6 and 10 mL of DMF were placed in a three-necked flask. The reaction was carried out at a constant voltage of 1.5 V for 12 hours with zinc as the positive electrode and nickel as the negative electrode to obtain monocarboxylated products. The substrates included benzene, chlorobenzene, bromobenzene, iodobenzene, anisole, nitrobenzene, aniline, biphenyl, naphthalene, benzonitrile and p-ethylphenol.

[0009] Aromatics sp 2 Preparation of diacid products with increased carbon chains by CH activation and CO2 carboxylation: In a CO2 atmosphere at 1 atm, 15 mg of catalyst, 0.5 mmol of substrate, 1 mmol of N-Bu4NPF6 and 10 mL of MeCN were placed in a three-necked flask. The reaction was carried out at a constant voltage of 1.5 V for 12 hours with zinc as the positive electrode and nickel as the negative electrode to obtain dicarboxylated products. The substrates included benzene, chlorobenzene, bromobenzene, iodobenzene, anisole, nitrobenzene, aniline, biphenyl and naphthalene.

[0010] A layered double metal hydroxide (LDH) in heterogeneous electrocatalysis sp 2 The application of C–H activation and CO2 carboxylation is characterized by the fact that the yield of carboxylic acids with increased carbon chains can reach 53%~93%.

[0011] A layered double metal hydroxide (LDH) in heterogeneous electrocatalysis sp 2 The application of C–H activation and CO2 carboxylation is characterized by the following: 15 mg of catalyst, 0.5 mmol of substrate, 1 mmol of N-Bu4NPF6, and 10 mL of solvent are placed in a three-necked flask. A zinc plate is used as the positive electrode, a nickel plate as the negative electrode, and the reaction is carried out at a constant voltage of 1.5 V for 12 hours. When DMF is used as the solvent, the selectivity for the formation of benzoic acid from benzene reaches 94%, and the separation yield reaches 93%. When acetonitrile is used as the solvent, the selectivity for the formation of isophthalic acid from benzene reaches 93%, and the separation yield reaches 90%.

[0012] A layered double metal hydroxide (LDH) in heterogeneous electrocatalysis sp 2The application of C–H activation and CO2 carboxylation is characterized by the following: CoFe-Mo LDH is recovered after use, washed, centrifuged, and dried for use in the next cycle. In the second, third, and fourth cycle experiments, the toluene conversion rate and selectivity can be maintained at a level of over 90%; by the fifth cycle, the conversion rate is maintained at over 86% and the selectivity is maintained at over 89%. Attached Figure Description

[0013] Figure 1 is the XRD pattern of the LDH catalyst prepared in Example 1; Figure 2 a) shows a scanning electron microscope (SEM) image of CoFe-Mo LDH, a transmission electron microscope (TEM) image of CoFe-Mo LDH b) and c) shows a high-resolution transmission electron microscope (HRTEM) image; Figure 3 a) shows the full X-ray photoelectron spectroscopy (XPS) of CoFe-Mo LDH, b) Co 2p, c) Fe 2p, d) Mo 3d, and e) O 1s XPS; Figure 4 a) XRD patterns of the two catalytic systems CoFe-Mo LDH before and after cycling, b) TGA curves of acetonitrile-intercalated CoFe-Mo LDH and CoFe-Mo LDH. Detailed Implementation

[0014] The present invention will now be described in detail with reference to specific embodiments.

[0015] Example 1: CoFe-C LDH, a carbonate-intercalated cobalt-iron hydrotalcite, was synthesized in one step via a coprecipitation method. Co(NO3)2•6H2O and Fe(NO3)3•9H2O (cobalt / iron molar ratio = 3:1) were dissolved in H2O to prepare a 0.6 M solution A. Separately, 0.4 g NaOH (10 mmol) and 2.1 g Na2CO3 (20 mmol) were dissolved in H2O with stirring to obtain solution B. Solutions A and B were simultaneously and slowly added dropwise to a three-necked flask containing 5 mL of H2O under stirring in a 60 °C water bath. The pH of the system was adjusted to 9.0, and the reaction was continued with stirring for 0.5 h. The resulting suspension was then transferred to a PTFE-lined stainless steel reactor and subjected to hydrothermal reaction at 80 °C for 48 h. After cooling to room temperature, the precipitate was collected by centrifugation, thoroughly washed with deionized H₂O and EtOH, and finally dried at 60 °C to obtain CoFe-C LDH. For comparison, NiFe-C LDH and NiCo-C LDH were synthesized using the exact same experimental procedure, with only the crystallization conditions adjusted: NiFe-C was crystallized at pH 8.5 and 120 °C, while NiCo-C was prepared at pH 9 and 80 °C. Preparation of molybdate-intercalated cobalt-iron layered double hydroxide catalyst: CoFe-MoLDH was synthesized in one step via a coprecipitation method. Deionized water was bubbled with nitrogen for 30 min to remove CO2, and the entire experiment was conducted under nitrogen protection. First, Co(NO3)2•6H2O and Fe(NO3)3•9H2O with a Co / Fe molar ratio of 3:1 were dissolved in deionized water to form a 0.6 M salt solution C. Then, 10 mL of sodium molybdate aqueous solution was prepared, n(MoO4) 2- ): n(Fe 3 + The ratio of solution C to solution D was 2:1, and the pH was adjusted to 9-9.5 with 0.5M NaOH. Solutions C and D were simultaneously added dropwise to a three-necked flask containing a small amount of deionized water, and the mixture was vigorously stirred in a 60℃ water bath. The resulting slurry was placed in a hydrothermal reactor and crystallized at 80℃ for 48 h. It was then thoroughly washed by centrifugation with deionized water and ethanol, and finally dried overnight at 60℃ to obtain the CoFe-Mo LDH sample.

[0016] X-ray diffraction patterns were used to detect the crystal phase of CoFe-Mo LDH. Figure 1 shows the diffraction peaks of CoFe-Mo LDH in two solvent systems. All diffraction peaks of CoFe-Mo LDH correspond to the layered structure of LDH. The characteristic peaks are at 11.4°, 23.2°, 34.0°, and 58.9°, which correspond to the (003), (006), (012), and (110) crystal planes of CoFe-Mo LDH (JCPDS No. 50-0235 and JCPDS No. 50.0739, respectively).

[0017] The morphology and structural characteristics of CoFe-Mo LDH were analyzed by scanning electron microscopy (SEM). Figure 2 The SEM images in image a show that the material exhibits a nanosheet morphology with a smooth surface and disordered stacking. Numerous uniformly sized nanosheets are in close contact, evenly distributed, and exhibit an interlaced stacking phenomenon. This interfacial structure exposes more active sites, thereby enhancing catalytic performance. Transmission electron microscopy (TEM) is also used. Figure 2 b) Further verification of its nanosheet morphology; under high-resolution transmission electron microscopy (HRTEM, Figure 2 c) Lattice fringes can be observed in the image, with a spacing of approximately 0.29 nm, corresponding to the (110) crystal plane of CoFe-MoLDH. X-ray photoelectron spectroscopy (XPS) measurements were performed to investigate the surface chemical state of the material: full spectrum ( Figure 3 a) The presence of Co, Fe, Mo, and O elements was confirmed, indicating that MoO4 2- Intercalation successful. In Co 2p ( Figure 3 b) In the spectrum, the characteristic peaks at 780.4 eV and 795.9 eV correspond to Co. 3+ The peaks at 782.2 eV and 797.4 eV are attributed to Co. 2+ Satellite peaks appeared at 786.0 eV and 802.9 eV, respectively. In the Fe 2p spectrum ( Figure 3 c) The peaks at 711.5 eV and 723.9 eV are attributed to Fe. 3+ The peaks at 715.0 eV and 726.6 eV correspond to Fe 2+ Simultaneously, satellite peaks appear at 717.5 eV and 734.4 eV. In the Mo 3d spectrum ( Figure 3 d) The binding energy peaks of 231.9 eV and 234.8 eV are attributed to the spin orbitals of Mo 3d 5 / 2 and Mo 3d 3 / 2, respectively. In the O 1s spectrum ( Figure 3e) The three characteristic peaks of 530.0 eV, 531.3 eV, and 532.8 eV correspond to the metal-oxygen bond, hydroxyl group, and adsorbed water, respectively. All the above XPS results are consistent with those of MoO4. 2- The intercalated cobalt-iron hydrotalcite exhibits consistent structural characteristics. After the reaction in DMF and acetonitrile, the CoFe-Mo LDH was characterized by XRD (Figure 4a). No significant changes were observed in the DMF catalytic system. In the MeCN catalytic system, a new diffraction peak was observed at 2θ = 29.6°, attributed to the intercalation of acetonitrile molecules into the interlayer of CoFe-Mo LDH. Thermogravimetric analysis (TGA) curves of CoFe–Mo LDH (Figure 4b) showed four main weight loss processes within four temperature ranges: 50–160 °C, 180–300 °C, 300–370 °C, and 370–600 °C. The total weight loss rates of the original CoFe–Mo LDH and the acetonitrile-recovered sample were 32.8% and 35.7%, respectively. The weight loss at each stage can be attributed as follows: the first stage corresponds to the removal of surface-adsorbed water; the second stage is attributed to the release of interlayer water; and the third stage originates from the removal of interlayer hydroxide ions. Within this temperature range, the layered bimetallic hydroxide undergoes decarbonization and dehydroxylation reactions, releasing water and ultimately forming a metal oxide. The weight loss in the fourth (final) stage is attributed to the removal of acetonitrile, an organic complex tightly bound to CoFe–Mo LDH.

[0018] Example 2 (Reaction reference Table 1, Item 1) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol benzene, 1 mmol n-Bu4NPF6, and 10 mL DMF were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, a nickel electrode as the negative electrode, and the reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of benzene and the selectivity of benzoic acid were analyzed by HPLC. The conversion rate of benzene was 94%, and the selectivity of benzoic acid was 100%.

[0019] Example 3 (Reaction reference Table 1, item 2) In a CO2 atmosphere at 1 atm, 0 mg CoFe-Mo LDH, 0.5 mmol benzene, 1 mmol n-Bu4NPF6, and 10 mL DMF were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, a nickel electrode as the negative electrode, and the reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of benzene and the selectivity of benzoic acid were analyzed by HPLC. The conversion rate of benzene was 12%, and the selectivity of benzoic acid was 100%.

[0020] Example 4 (Reaction reference Table 1, item 3) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol benzene, 1 mmol n-Bu4NPF6, and 10 mL DMF were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, and a nickel electrode as the negative electrode. The reaction was carried out at a constant voltage of 0.0 V for 12 hours. The conversion rate of benzene and the selectivity of benzoic acid were analyzed by HPLC. The conversion rate of benzene was 0%.

[0021] Example 5 (Reaction reference Table 1, item 4) In an argon atmosphere, 15 mg of CoFe-Mo LDH, 0.5 mmol of benzene, 1 mmol of N-Bu4NPF6, and 10 mL of DMF were placed in a three-necked flask as solvents. A zinc electrode was used as the positive electrode, and a nickel electrode as the negative electrode. The reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of benzene and the selectivity of benzoic acid were analyzed by HPLC. The conversion rate of benzene was 0%.

[0022] Example 6 (Reaction reference Table 1, item 5) In a CO2 atmosphere at 1 atm, 15 mg NiFe-C LDH, 0.5 mmol benzene, 1 mmol n-Bu4NPF6, and 10 mL DMF were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, and a nickel electrode as the negative electrode. The reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of benzene and the selectivity of benzoic acid were analyzed by HPLC. The conversion rate of benzene was 80%, and the selectivity of benzoic acid was 100%.

[0023] Example 7 (Reaction reference Table 1, item 6) In a CO2 atmosphere at 1 atm, 15 mg CoFe-C LDH, 0.5 mmol benzene, 1 mmol n-Bu4NPF6, and 10 mL DMF were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, a nickel electrode as the negative electrode, and the reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of benzene and the selectivity of benzoic acid were analyzed by HPLC. The conversion rate of benzene was 87%, and the selectivity of benzoic acid was 100%.

[0024] Example 8 (Reaction reference Table 1, item 7) In a CO2 atmosphere at 1 atm, 15 mg NiCo-C LDH, 0.5 mmol benzene, 1 mmol n-Bu4NPF6, and 10 mL DMF were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, a nickel electrode as the negative electrode, and the reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of benzene and the selectivity of benzoic acid were analyzed by HPLC. The conversion rate of benzene was 84%, and the selectivity of benzoic acid was 100%.

[0025] Example 9 (Reaction reference Table 1, item 8) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol benzene, 1 mmol n-Bu4NPF6, and 10 mL DMF were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, a nickel electrode as the negative electrode, and the reaction was carried out at a constant voltage of 0.5 V for 12 hours. The conversion rate of benzene and the selectivity of benzoic acid were analyzed by HPLC. The conversion rate of benzene was 0%, and the selectivity of benzoic acid was 100%.

[0026] Example 10 (Reaction reference Table 1, item 9) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol benzene, 1 mmol n-Bu4NPF6, and 10 mL DMF were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, and a nickel electrode as the negative electrode. The reaction was carried out at a constant voltage of 1.0 V for 12 hours. The conversion rate of benzene and the selectivity of benzoic acid were analyzed by HPLC. The conversion rate of benzene was 56%, and the selectivity of benzoic acid was 100%.

[0027] Example 11 (Reaction reference Table 1, item 10) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol benzene, 1 mmol n-Bu4NPF6, and 10 mL DMF were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, a nickel electrode as the negative electrode, and the reaction was carried out at a constant voltage of 2.0 V for 12 hours. The conversion rate of benzene and the selectivity of benzoic acid were analyzed by HPLC. The conversion rate of benzene was 94%, and the selectivity of benzoic acid was 100%.

[0028] Example 12 (Reaction reference Table 1, item 11) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol benzene, 1 mmol n-Bu4NPF6, and 10 mL DMF were added as solvents to a three-necked flask. An aluminum plate was used as the positive electrode, a nickel plate as the negative electrode, and the reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of benzene and the selectivity of benzoic acid were analyzed by HPLC. The conversion rate of benzene was 85%, and the selectivity of benzoic acid was 100%.

[0029] Example 13 (Reaction reference Table 1, item 12) In a CO2 atmosphere at 1 atm, 15 mg of CoFe-Mo LDH, 0.5 mmol of benzene, 1 mmol of n-Bu4NPF6, and 10 mL of DMF were placed in a three-necked flask as solvents. An iron plate was used as the positive electrode, a nickel plate as the negative electrode, and the reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of benzene and the selectivity of benzoic acid were analyzed by HPLC. The conversion rate of benzene was 88%, and the selectivity of benzoic acid was 100%.

[0030] Example 14 (Reaction reference Table 1, item 13) In a CO2 atmosphere at 1 atm, 15 mg of CoFe-Mo LDH, 0.5 mmol of benzene, 1 mmol of n-Bu4NPF6, and 10 mL of NMP were placed in a three-necked flask as solvents. A zinc electrode was used as the positive electrode, and a nickel electrode as the negative electrode. The reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of benzene and the selectivity of benzoic acid were analyzed by HPLC. The conversion rate of benzene was 60%, and the selectivity of benzoic acid was 95%.

[0031] Example 15 (Reaction reference Table 1, item 14) In a CO2 atmosphere at 1 atm, 15 mg of CoFe-Mo LDH, 0.5 mmol of benzene, 1 mmol of n-Bu4NPF6, and 10 mL of DMA were placed in a three-necked flask as solvents. A zinc electrode was used as the positive electrode, and a nickel electrode as the negative electrode. The reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of benzene and the selectivity of benzoic acid were analyzed by HPLC. The conversion rate of benzene was 83%, and the selectivity of benzoic acid was 94%.

[0032] Example 16 (Reaction reference Table 1, item 15) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol benzene, 1 mmol n-Bu4NPF6, and 10 mL MeCN were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, a nickel electrode as the negative electrode, and the reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of benzene and the selectivity of benzoic acid were analyzed by HPLC. The conversion rate of benzene was 95%, and the selectivity of isophthalic acid was 95%.

[0033] Example 17 (Reaction reference Table 1, item 16) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol benzene, 1 mmol n-Bu4NPF6, and 10 mL H2O were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, and a nickel electrode as the negative electrode. The reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of benzene and the selectivity of benzoic acid were analyzed by HPLC. The conversion rate of benzene was 86%, and the selectivity of benzoic acid was 93%.

[0034] Example 18 (Reaction reference Table 1, item 17) In a CO2 atmosphere at 1 atm, 15 mg of CoFe-Mo LDH, 0.5 mmol of benzene, 1 mmol of n-Bu4NBF4, and 10 mL of DMF were placed in a three-necked flask as solvents. A zinc electrode was used as the positive electrode, a nickel electrode as the negative electrode, and the reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of benzene and the selectivity of benzoic acid were analyzed by HPLC. The conversion rate of benzene was 86%, and the selectivity of benzoic acid was 100%.

[0035] Example 19 (Reaction reference Table 1, item 18) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol benzene, 1 mmol n-BuNClO4, and 10 mL DMF were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, a nickel electrode as the negative electrode, and the reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of benzene and the selectivity of benzoic acid were analyzed by HPLC. The conversion rate of benzene was 87%, and the selectivity of benzoic acid was 99%.

[0036] Example 20 (Reaction reference Table 1, item 19) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol benzene, 1 mmol n-Et4NBr, and 10 mL DMF were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, a nickel electrode as the negative electrode, and the reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of benzene and the selectivity of benzoic acid were analyzed by HPLC. The conversion rate of benzene was 84%, and the selectivity of benzoic acid was 98%.

[0037] Example 21 (Reaction reference Table 1, item 20) In a CO2 atmosphere at 1 atm, 15 mg of recycled CoFe-Mo LDH (recycled four times), 0.5 mmol of benzene, 1 mmol of n-Et4NBr, and 10 mL of DMF were placed in a three-necked flask as solvents. A zinc electrode was used as the positive electrode, a nickel electrode as the negative electrode, and the reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of benzene and the selectivity of benzoic acid were analyzed by HPLC. The conversion rate of benzene was 90%, and the selectivity of benzoic acid was 100%.

[0038]

[0039] Example 22 (Reaction reference Table 2, substrate 2a) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol chlorobenzene, 1 mmol n-Bu4NPF6, and 10 mL DMF were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, a nickel electrode as the negative electrode, and the reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of chlorobenzene and the selectivity of benzoic acid were analyzed by HPLC. The conversion rate of chlorobenzene was 92%, and the separation yield of benzoic acid was 90%.

[0040] Example 23 (Reaction reference Table 2, substrate 3a) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol bromobenzene, 1 mmol n-Bu4NPF6, and 10 mL DMF were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, a nickel electrode as the negative electrode, and the reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of bromobenzene and the selectivity of benzoic acid were analyzed by HPLC. The conversion rate of bromobenzene was 98%, and the separation yield of benzoic acid was 95%.

[0041] Example 24 (Reaction reference Table 2, Substrate 4a) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol iodobenzene, 1 mmol n-Bu4NPF6, and 10 mL DMF were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, a nickel electrode as the negative electrode, and the reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of iodobenzene and the selectivity of benzoic acid were analyzed by HPLC. The conversion rate of iodobenzene was 96%, and the separation yield of benzoic acid was 94%.

[0042] Example 25 (Reaction reference Table 2, substrate 5a) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol nitrobenzene, 1 mmol n-Bu4NPF6, and 10 mL DMF were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, and a nickel electrode as the negative electrode. The reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of nitrobenzene and the selectivity of m-nitrobenzene were analyzed by HPLC. The conversion rate of nitrobenzene was 61%, and the separation yield of m-nitrobenzene was 58%.

[0043] Example 26 (Reaction reference Table 2, substrate 6a) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol aniline, 1 mmol n-Bu4NPF6, and 10 mL DMF were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, a nickel electrode as the negative electrode, and the reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of aniline and the selectivity of p-aminobenzoic acid were analyzed by HPLC. The conversion rate of aniline was 88%, and the separation yield of p-aminobenzoic acid was 85%.

[0044] Example 27 (Reaction reference Table 2, substrate 7a) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol anisole, 1 mmol n-Bu4NPF6, and 10 mL DMF were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, a nickel electrode as the negative electrode, and the reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of anisole and the selectivity for p-methoxybenzoic acid were analyzed by HPLC. The conversion rate of anisole was 84%, and the separation yield of p-methoxybenzoic acid was 80%.

[0045] Example 28 (Reaction reference Table 2, substrate 8a) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol biphenyl, 1 mmol n-Bu4NPF6, and 10 mL DMF were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, a nickel electrode as the negative electrode, and the reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of biphenyl and the selectivity of 4-phenylbenzoic acid were analyzed by HPLC. The conversion rate of biphenyl was 76%, and the yield of 4-phenylbenzoic acid was 71%.

[0046] Example 29 (Reaction reference Table 2, substrate 9a) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol naphthalene, 1 mmol n-Bu4NPF6, and 10 mL DMF were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, a nickel electrode as the negative electrode, and the reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of naphthalene and the selectivity for 1-naphthoic acid were analyzed by HPLC. The conversion rate of naphthalene was 80%, and the yield of 1-naphthoic acid was 76%.

[0047] Example 30 (Reaction reference Table 2, substrate 10a) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol benzonitrile, 1 mmol n-Bu4NPF6, and 10 mL DMF were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, and a nickel electrode as the negative electrode. The reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of benzonitrile and the selectivity of m-cyanobenzoic acid were analyzed by HPLC. The conversion rate of benzonitrile was 60%, and the separation yield of m-cyanobenzoic acid was 56%.

[0048] Example 31 (Reaction reference Table 2, substrate 11a) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol p-ethylanisole, 1 mmol n-Bu4NPF6, and 10 mL DMF were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, a nickel electrode as the negative electrode, and the reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of p-ethylanisole and the selectivity for 2-methoxy-5-ethylbenzoic acid were analyzed by HPLC. The conversion rate of p-ethylanisole was 74%, and the yield of 2-methoxy-5-ethylbenzoic acid was 70%.

[0049]

[0050] Example 32 (Reaction reference Table 3, Substrate 2a) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol chlorobenzene, 1 mmol n-Bu4NPF6, and 10 mL MeCN were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, a nickel electrode as the negative electrode, and the reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of chlorobenzene and the selectivity of isophthalic acid were analyzed by HPLC. The conversion rate of benzene was 77%, and the separation yield of isophthalic acid was 70%.

[0051] Example 33 (Reaction reference Table 3, Substrate 3a) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol bromobenzene, 1 mmol n-Bu4NPF6, and 10 mL MeCN were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, a nickel electrode as the negative electrode, and the reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of bromobenzene and the selectivity of isophthalic acid were analyzed by HPLC. The conversion rate of benzene was 86%, and the separation yield of isophthalic acid was 82%.

[0052] Example 34 (Reaction reference Table 3, Substrate 4a) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol iodobenzene, 1 mmol n-Bu4NPF6, and 10 mL MeCN were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, a nickel electrode as the negative electrode, and the reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of iodobenzene and the selectivity of isophthalic acid were analyzed by HPLC. The conversion rate of benzene was 96%, and the separation yield of benzoic acid was 90%.

[0053] Example 35 (Reaction reference Table 3, Substrate 6a) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol nitrobenzene, 1 mmol n-Bu4NPF6, and 10 mL MeCN were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, a nickel electrode as the negative electrode, and the reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of nitrobenzene and the selectivity for 5-nitroisophthalic acid were analyzed by HPLC. The conversion rate of benzene was 58%, and the yield of 5-nitroisophthalic acid was 53%.

[0054] Example 36 (Reaction reference Table 3, Substrate 7a) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol aniline, 1 mmol n-Bu4NPF6, and 10 mL MeCN were added as solvent to a three-necked flask. A zinc electrode was used as the positive electrode, a nickel electrode as the negative electrode, and the reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of aniline and the selectivity of 5-aminoisophthalic acid were analyzed by HPLC. The conversion rate of benzene was 85%, and the yield of 5-aminoisophthalic acid was 81%.

[0055] Example 37 (Reaction reference Table 3, Substrate 8a) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol phenol, 1 mmol n-Bu4NPF6, and 10 mL MeCN were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, a nickel electrode as the negative electrode, and the reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of phenol and the selectivity for 2-hydroxyisophthalic acid were analyzed by HPLC. The conversion rate of benzene was 80%, and the yield of 2-hydroxyisophthalic acid was 76%.

[0056] Example 38 (Reaction reference Table 3, Substrate 9a) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol anisole, 1 mmol n-Bu4NPF6, and 10 mL MeCN were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, a nickel electrode as the negative electrode, and the reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of anisole and the selectivity for 3-methoxyisophthalic acid were analyzed by HPLC. The conversion rate of benzene was 82%, and the yield of 3-methoxyisophthalic acid was 80%.

[0057] Example 39 (Reaction reference Table 3, Substrate 10a) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol biphenyl, 1 mmol n-Bu4NPF6, and 10 mL MeCN were added as solvents to a three-necked flask. A zinc electrode was used as the positive electrode, a nickel electrode as the negative electrode, and the reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of biphenyl and the selectivity for 4,4'-biphenyl dicarboxylic acid were analyzed by HPLC. The conversion rate of benzene was 75%, and the yield of 4,4'-biphenyl dicarboxylic acid was 71%.

[0058] Example 40 (Reaction reference Table 3, Substrate 11a) In a CO2 atmosphere at 1 atm, 15 mg CoFe-Mo LDH, 0.5 mmol naphthalene, 1 mmol n-Bu4NPF6, and 10 mL MeCN were added as solvent to a three-necked flask. A zinc electrode was used as the positive electrode, a nickel electrode as the negative electrode, and the reaction was carried out at a constant voltage of 1.5 V for 12 hours. The conversion rate of benzene and the selectivity of benzoic acid were analyzed by HPLC. The conversion rate of naphthalene was 80%, and the yield of 2,6-naphthalenedicarboxylic acid was 75%.

[0059]

Claims

1. An LDH electrocatalyst in sp 2 Its application in CH activation and selective mono / dicarboxylation of CO2 is characterized by Aromatic hydrocarbons underwent monocarboxylation with DMF as the solvent and dicarboxylation with MeCN as the solvent. A co-precipitation method was used to synthesize molybdate-intercalated cobalt-iron hydrotalcite (CoFe-Mo LDH) in one step. Deionized water was bubbled with nitrogen for 30 min to remove CO2. The entire experiment was conducted under nitrogen protection. First, Co(NO3)2•6H2O and Fe(NO3)3•9H2O with a Co / Fe molar ratio of 3:1 were dissolved in deionized water to form a 0.6 M salt solution A. Then, 10 mL of sodium molybdate aqueous solution was prepared, n(MoO4) 2- ): n(Fe 3+ The ratio of A to B was 2:1, and the pH was adjusted to 9-9.5 with 0.5M NaOH to obtain solution B. Solution A and solution B were simultaneously added dropwise to a three-necked flask containing a small amount of deionized water and stirred vigorously in a 60℃ water bath. The resulting slurry was placed in a hydrothermal reactor and heated at 80℃ for 48 h. Then, it was thoroughly washed by centrifugation with deionized water and ethanol, and finally dried at 60℃ overnight to obtain the CoFe-Mo LDH sample. Aromatics sp 2 Preparation of monoacid products with increased carbon chains by CH activation and CO2 carboxylation: In a CO2 atmosphere at 1 atm, 15 mg of catalyst, 0.5 mmol of substrate, 1 mmol of N-Bu4NPF6 and 10 mL of DMF were placed in a three-necked flask. The reaction was carried out at a constant voltage of 1.5 V for 12 hours with zinc as the positive electrode and nickel as the negative electrode to obtain monocarboxylated products. The substrates included benzene, chlorobenzene, bromobenzene, iodobenzene, anisole, nitrobenzene, aniline, biphenyl, naphthalene, benzonitrile and p-ethylphenol. Aromatics sp 2 Preparation of diacid products with increased carbon chains by CH activation and CO2 carboxylation: In a CO2 atmosphere at 1 atm, 15 mg of catalyst, 0.5 mmol of substrate, 1 mmol of N-Bu4NPF6 and 10 mL of MeCN were placed in a three-necked flask. The reaction was carried out at a constant voltage of 1.5 V for 12 hours with zinc as the positive electrode and nickel as the negative electrode to obtain dicarboxylated products. The substrates included benzene, chlorobenzene, bromobenzene, iodobenzene, anisole, nitrobenzene, aniline, biphenyl and naphthalene.

2. An LDH electrocatalyst in sp 2 Its application in CH activation and selective mono / dicarboxylation of CO2 is characterized by... The yield of carboxylic acids with increased carbon chain can reach 56% to 95%.

3. An LDH electrocatalyst in sp 2 Its application in CH activation and selective mono / dicarboxylation of CO2 is characterized by... CoFe-Mo LDH was recovered after use, washed, centrifuged, and dried for use in the next cycle. In the second, third, and fourth cycles, the benzene conversion and selectivity were maintained at over 90%. By the fifth cycle, the conversion was maintained at over 89% and the selectivity was maintained at 100%.

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