La-doped Pd-CeO2 monatomic catalyzed aromatic hydrocarbon deuteration method
By reacting La-doped Pd-CeO2 single-atom catalyst with heavy water at normal pressure, the problems of expensive catalysts and harsh reaction conditions in the synthesis of existing deuterated aromatic hydrocarbons are solved, and deuterated reactions are achieved with high efficiency and good selectivity, which is suitable for industrial applications.
Patent Information
- Application Number
- CN202510280347.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-11
- Publication Date
- 2025-07-04
AI Technical Summary
The existing deuterated aromatic hydrocarbon synthesis methods have problems such as expensive catalysts, harsh reaction conditions, many by-products, low purity and yield, and it is difficult to meet industrial needs.
La doped Pd-CeO2 single-atom catalyst is used to react with heavy water at normal pressure, and the high-efficiency deuterated aromatic hydrocarbons are achieved by regulating the active site of the catalyst. The catalyst is prepared simple and the reaction conditions are mild.
It achieves a deuterated reaction with high selectivity and high yield, reduces the generation of by-products, and has high catalyst stability, making it suitable for industrial applications.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of deuterated compound production, and particularly to a method for deuterating aromatic hydrocarbons catalyzed by La-doped Pd-CeO2 single atoms. Background Art
[0002] Deuterated aromatic hydrocarbons (such as deuterated benzene, deuterated naphthalene, etc.), as important deuterated compounds, have irreplaceable application values in the fields of nuclear magnetic resonance (NMR), mass spectrometry analysis, drug metabolism research, and high-precision analysis. Especially in the fields of biomedicine and materials science, deuterated benzene and deuterated polycyclic aromatic hydrocarbons have become indispensable basic raw materials in the research and development of next-generation organic optoelectronic materials (such as deuterated OLED) and deuterated drugs due to their excellent optoelectronic properties, thermal stability, and metabolic resistance. With the growth of market demand, especially driven by deuterated OLED, deuterated drugs, and high-precision analysis technologies, the demand for deuterated aromatic hydrocarbons has increased significantly, and higher requirements have been put forward for the purity, selectivity, and economy of their synthesis processes.
[0003] However, the synthesis of deuterated aromatic hydrocarbons faces many technical challenges. Taking the preparation of deuterated benzene as an example, there are two relatively mature preparation routes: 1) Using deuterated sulfuric acid (52%) as a catalyst, benzene and heavy water are used to prepare through a hydrogen / deuterium (H / D) exchange reaction. The reaction conditions of this synthesis route are mild. After reacting at room temperature for 72 hours and undergoing four rounds of exchange, the deuteration degree can reach 99.8%. However, this method requires the use of high-concentration deuterated sulfuric acid, which is dangerous to operate, and sulfur trioxide (SO3) required for preparing deuterated sulfuric acid has a strong pungent odor and can cause serious pollution to the atmosphere and harm to the environment. Secondly, benzene will undergo a sulfonation reaction under the action of concentrated sulfuric acid to generate by-product benzenesulfonic acid, which affects the purity and yield of the reaction product (J. Chem. Soc., 1936, 915); 2) Using platinum-carbon (Pt / C) as a catalyst, benzene and heavy water are prepared through an H / D exchange reaction. After reacting at 110°C for four rounds of exchange, a deuteration degree of 95% can be obtained. The catalyst used in this method is expensive and has poor economy; at the same time, over-reduction will occur during the reaction to generate by-product cyclohexane, whose boiling point (80.74°C) is almost the same as that of deuterated benzene (79.1°C), and the reaction product cannot be separated during the post-treatment of the reaction, resulting in low purity of the reaction product. In addition, this method requires a high-temperature and high-pressure environment for the reaction, the reaction conditions are harsh, and the safety index is low, making it difficult to meet the requirements of industrial production (Can. J. Chem., 1954, 32, 813).
[0004] In the study of aromatic hydrocarbon deuteration, palladium (Pd) catalysis is an important method. By regulating the electronic structure of its active center, Pd catalysts can selectively introduce deuterium onto the aromatic ring without a directing group, especially showing good selectivity and high efficiency in the deuteration reactions of small aromatic hydrocarbons such as benzene and naphthalene. However, the Pd-catalyzed method also has some limitations, such as expensive catalysts, the need for specific ligands, and harsh reaction conditions (such as high temperature and high pressure), which to a certain extent limit its industrial application (Angew. Chem. Int. Ed., 2007, 46, 2269; Angew. Chem. Int. Ed., 2024, e202410162). In addition, Pd catalysts are prone to deactivation or poisoning in some reactions, further increasing the complexity and cost of the process. Therefore, the development of an efficient, highly selective, and economically feasible deuteration synthesis method has become the focus of current research. Summary of the Invention
[0005] The object of the present invention is to provide a method for deuterating aromatic hydrocarbons catalyzed by La-doped Pd-CeO2 single atoms. A La-doped Pd-CeO2 single-atom catalyst is used, and heavy water is used as the deuterium source for deuterating aromatic hydrocarbon substrates. The catalyst is simple to prepare, the reaction conditions are mild, the deuteration degree and yield are high, and the separation is simple.
[0006] The technical solution adopted by the present invention to solve its technical problems is: A method for deuterating aromatic hydrocarbons catalyzed by La-doped Pd-CeO2 single atoms, using aromatic hydrocarbons as raw materials, in an atmospheric pressure system, with or without adding a solvent, undergoes a deuteration reaction with heavy water under the action of a La-doped Pd-CeO2 single-atom catalyst, and the reaction product is separated and purified to obtain a deuterated product.
[0007] The present invention can achieve the deuteration of aromatic hydrocarbons using a relatively low catalyst dosage and mild conditions. The aromatic hydrocarbon substrates described can be directly purchased from reagent companies.
[0008] The aromatic hydrocarbon substrate is selected from one of benzene, toluene, anisole, chlorobenzene, bromobenzene, p-methylnitrobenzene, mesitylene, p-methylaniline, 2-phenylpropanol, diphenylmethane, acetophenone, methyl benzoate, naphthalene, anthracene, phenanthrene, fluorene, and carbazole; when the aromatic hydrocarbon is liquid, no solvent is added; when the aromatic hydrocarbon is solid, a solvent is added, and the dosage of the solvent is the same volume as that of heavy water, and the solvent is cyclohexane.
[0009] The molar ratio of aromatic hydrocarbon:deuterium source reagent = 1:30 - 1:100; the dosage of the La-doped Pd-CeO2 single-atom catalyst is 5 - 50% of the weight of the aromatic hydrocarbon.
[0010] The deuteration reaction temperature is 60 - 100 °C, and the reaction time is 24 - 48 hours.
[0011] The preparation method of La-doped Pd-CeO2 single-atom catalyst is as follows: 1) Dissolve cerium salt and lanthanum salt in deionized water to form a mixed solution, then add citric acid and stir to form a complex. Next, slowly add ammonia water or sodium hydroxide solution to adjust the pH value to 7-9, and the solution forms a gel. Dry the obtained gel to get a dry powder. Subsequently, transfer the dry powder to a high-temperature furnace and calcine it at 500-800 °C for 4-8 hours in an air atmosphere to obtain La-doped CeO2 powder; 2) Add the La-doped CeO2 powder into the palladium salt solution and stir evenly. Then place it under a hydrogen atmosphere or use a reducing agent for reduction. After the reduction is completed, wash it clean with deionized water and dry it to obtain the La-doped Pd-CeO2 single-atom catalyst.
[0012] In the design of the catalyst, due to its high oxygen storage capacity and rich surface defects, the CeO2 support can form a strong interaction with Pd atoms, prevent the aggregation of Pd atoms, and at the same time adjust the electronic structure of Pd, enhancing its catalytic activity. As the active center, Pd single atoms can efficiently activate the deuterium atoms in heavy water and achieve high-selectivity deuteration by precisely controlling the reaction path. La has a strong electron supply ability, which can effectively increase the density of oxygen vacancies on the surface of CeO2, improve the electronic structure of Pd. By regulating the surface defect density of the CeO2 support and the coordination environment of Pd atoms, the activity and selectivity of the catalyst can be optimized, promoting the occurrence of the deuteration reaction.
[0013] In the catalytic mechanism, the oxygen vacancies on the surface of La-doped CeO2 can adsorb and activate D2O molecules, dissociating them into deuterium atoms (D*). As the active center, Pd single atoms further promote the dissociation process of D2O and reduce the activation energy. Aromatic molecules bind to the surface of CeO2 through π-π interactions. At the same time, under the action of Pd single atoms, the C-H bonds on the aromatic ring are activated to form C-H intermediates. The activated deuterium atoms (D) react with the C-H* intermediates on the aromatic ring to undergo a hydrogen-deuterium exchange reaction, generating deuterated products. The high dispersion of Pd single atoms and the synergistic effect of the La-CeO2 support enable the deuteration reaction to proceed efficiently under mild conditions. After deuteration, the molecules desorb from the catalyst surface, releasing the active sites to prepare for the next catalytic cycle. The oxygen vacancies on the surface of La-doped CeO2 are dynamically regenerated during the reaction, ensuring the long-term stability of the catalyst.
[0014] A kind of La-doped Pd-CeO2 single-atom catalyst is prepared by the following steps: 1) Dissolve cerium salt and lanthanum salt in deionized water to form a mixed solution, then add citric acid and stir to form a complex. Next, slowly add ammonia water or sodium hydroxide solution to adjust the pH value to 7-9, and the solution forms a gel. Dry the obtained gel to get a dry powder. Subsequently, transfer the dry powder to a high-temperature furnace and calcine it at 500-800 °C for 4-8 hours in an air atmosphere to obtain La-doped CeO2 powder. This process not only removes the organic matter in the gel but also promotes the doping of La and CeO2, resulting in La-doped CeO2 powder.
[0015] 2) Add the La-doped CeO2 powder to the palladium salt solution and stir evenly. Then place it under a hydrogen atmosphere or use a reducing agent for reduction. After the reduction is completed, wash it thoroughly with deionized water and dry it to obtain the La-doped Pd-CeO2 single-atom catalyst. Reduction is to ensure that Pd ions are reduced to the single-atom form and are evenly dispersed on the surface of CeO2. After the reduction is completed, wash the catalyst thoroughly with deionized water to remove the unreacted Pd residues.
[0016] The catalyst of the present invention is simple to prepare. The deuteration reaction uses heavy water as the deuterium source, and has the characteristics of mild reaction conditions, a wide substrate range, and easy amplification of the reaction scale, and has potential commercial prospects.
[0017] In step 1), the cerium salt is one of Ce(NO3)3, Ce(NO3)3·6H2O, CeCl3, CeCl3·7H2O; The lanthanum salt is one of La(NO3)3, La(NO3)36H2O, LaCl3, LaCl3·7H2O; The molar ratio of cerium ions to lanthanum ions is 1-X∶X, where 0.1≤X≤0.3. In the mixed solution, the total concentration of cerium ions and lanthanum ions is 0.1-1.0 mol / L.
[0018] The total molar amount of cerium salt and lanthanum salt: the molar amount of citric acid = 1:1-3.
[0019] In step 2), the palladium salt is sodium chloropalladate, potassium chloropalladate or ammonium chloropalladate, and the mass ratio of CeO2∶Pd = 4-6:1.
[0020] In step 2), the reduction temperature under a hydrogen atmosphere is set between 100-200 °C and the reduction continues for 2-4 hours.
[0021] The beneficial effects of the present invention are: The La-doped Pd-CeO2 single-atom catalyst used in the present invention is simple to prepare, has high stability, and exhibits excellent performance in the synthesis of deuterated aromatics. By precisely regulating the active sites of the catalyst, efficient and highly selective deuteration reactions are achieved, while solving the limitations of traditional Pd catalysts. In the deuteration reaction of benzene and its derivatives, this catalyst can achieve a deuteration rate of up to 95% under heating conditions, and the product yield exceeds 90%. For the deuteration reaction of aromatics, this catalyst shows excellent catalytic activity, can achieve efficient deuteration at multiple different active positions, and significantly reduces the generation of by-products. The method for deuterating aromatics developed in the present invention has good operability, mild reaction conditions, high catalytic efficiency, a wide substrate range, and is easy to scale up the reaction scale, etc., and has potential commercial prospects. Detailed implementation manners
[0022] The technical solutions of the present invention will be further specifically described below through specific examples.
[0023] In the present invention, unless otherwise specified, the raw materials and equipment used can be purchased from the market or are commonly used in the art. The methods in the following examples are all conventional methods in the art unless otherwise specified.
[0024] Example 1: Cerium nitrate (0.0144 mol) and lanthanum nitrate (0.0016 mol) were added to 40 mL of deionized water, and heated and stirred until completely dissolved to obtain a precursor solution with a total concentration of Ce 3+ and La 3+ of 0.4 mol / L, and the molar ratio of Ce 3+ :La 3+ of 9:1. Then, an appropriate amount of citric acid (0.016 mol) was added and stirred to form metal ion complexes to ensure their uniform dispersion. Next, the pH value of the solution was adjusted. Ammonia water was slowly added dropwise to the solution to adjust the pH value to 7 until the solution began to form a transparent gel. The obtained gel was dried by hot air drying at 80 °C to obtain a dry powder. Subsequently, the dry powder was transferred to a high-temperature furnace and calcined at 800 °C in an air atmosphere for 4 hours. This process not only removed the organic matter in the gel but also promoted the doping of La and CeO2 to obtain La-doped CeO2 powder.
[0025] Take 30 mL of deionized water, add 4.5 g of the prepared La-doped CeO2 powder (Ce / La = 9 / 1), and then add 10 mL of an aqueous solution of sodium palladium chloride with a concentration of 100 g / L in deionized water. Stir at room temperature for 30 min. After dissolution, a metal salt solution is obtained. Place the mixed solution under a hydrogen atmosphere and continuously reduce it at 120 °C for 4 hours to ensure that Pd ions are reduced to the single-atom form and uniformly dispersed on the surface of CeO2. After the reduction is completed, thoroughly wash the catalyst with deionized water to remove unreacted Pd residues. Place the ceria-supported palladium solid in an environment with a temperature of 80 °C and dry it for 12 hours to obtain a Pa-La-CeO2 (Ce / La = 9 / 1) catalyst with a loading of approximately 4.8 wt%.
[0026] Example 2: The difference between this example and Example 1 is that: Add cerium nitrate (0.0032 mol) and lanthanum nitrate (0.0008 mol) to 40 mL of deionized water, heat and stir until dissolved to obtain a precursor solution with a total concentration of Ce 3+ and La 3+ of 0.1 mol / L and a Ce 3+ :La 3+ ratio of 8:2. Then, add an appropriate amount of citric acid (0.004 mol) and stir to form metal ion complexes and ensure their uniform dispersion.
[0027] Finally, a Pa-La-CeO2 (Ce / La = 8 / 2) catalyst with a loading of approximately 4.56 wt% is obtained.
[0028] Example 3: The difference between this example and Example 1 is that: Add cerium nitrate (0.028 mol) and lanthanum nitrate (0.012 mol) to 40 mL of deionized water, heat and stir until dissolved to obtain a precursor solution with a total concentration of Ce 3+ and La 3+ of 0.1 mol / L and a Ce 3+ :La 3+ ratio of 7:3. Then, add an appropriate amount of citric acid (0.08 mol) and stir to form metal ion complexes and ensure their uniform dispersion.
[0029] Finally, a Pa-La-CeO2 (Ce / La = 7 / 3) catalyst with a loading of approximately 4.1 wt% is obtained.
[0030] Example 4: The difference between this example and Example 1 is that: The cerium salt used is cerium chloride and the lanthanum salt is lanthanum chloride; According to the mass ratio of CeO2∶Pd = 6:1, take 30 mL of deionized water, add the prepared La-doped CeO2 powder (Ce / La = 9 / 1), and then add an aqueous solution of sodium palladium chloride with a concentration of 100 g / L in deionized water. Stir at room temperature for 30 min, and a metal salt solution is obtained after dissolution. Finally, a Pa-La-CeO2 (Ce / La = 9 / 1) catalyst with a loading of about 4.84 wt% is obtained.
[0031] Example 5: The difference between this example and Example 1 is that: Add cerium nitrate (0.0144 mol) and lanthanum nitrate (0.0016 mol) to 16 mL of deionized water, heat and stir until completely dissolved to obtain a precursor solution with a total concentration of Ce 3+ and La 3+ of 1 mol / L and a Ce 3+ :La 3+ ratio of 9:1. Then, add an appropriate amount of citric acid (0.048 mol) and stir to form metal ion complexes to ensure their uniform dispersion.
[0032] According to the mass ratio of CeO2∶Pd = 4:1, take 30 mL of deionized water, add the prepared La-doped CeO2 powder (Ce / La = 9 / 1), and then add an aqueous solution of sodium palladium chloride with a concentration of 100 g / L in deionized water. Stir at room temperature for 30 min, and a metal salt solution is obtained after dissolution.
[0033] Example 6: Synthesis of deuterated benzene In a 15 mL dry sealed tube, successively add 1.0 mmol (78 mg) of benzene, the Pa-La-CeO2 (Ce / La = 9 / 1) catalyst prepared in Example 1 (16 mg, 20 w%), 1.0 mL of D2O, and stir at 80 °C under a nitrogen atmosphere for 24 hours.
[0034] After the reaction is completed, stop stirring, cool to room temperature, filter off the catalyst, separate the liquid with a separatory funnel, retain the upper layer liquid, then dry with anhydrous sodium sulfate, filter, and rotary evaporate to obtain the product; 72 mg of the target compound deuterated benzene is obtained with a yield of 91% and a deuteration degree of 98%. 1 H NMR (400 MHz, DMSO-d6) δ7.26( s, 0.12H )。
[0035] Under the same substrate as in Example 5, change the reaction parameters: Example 7 The difference between this example and Example 6 is that: The addition amount of D2O is 30 mmol.
[0036] Example 8 The difference between this example and Example 6 is that: The addition amount of D2O is 100 mmol.
[0037] Example 9: Synthesis of deuterated naphthalene Into a 15 mL dry sealed tube, 1.0 mmol (128 mg) of naphthalene, the Pa-La-CeO2 (Ce / La = 9 / 1) catalyst prepared in Example 1 (16 mg, 20 w%), 1.0 mL of D2O, and 1.0 mL of cyclohexane were successively added, and stirred at 80 °C under a nitrogen atmosphere for 24 hours.
[0038] After the reaction was completed, the stirring was stopped, cooled to room temperature, the catalyst was filtered off, the liquid was separated with a separatory funnel, the upper layer liquid was retained, then dried over anhydrous sodium sulfate, filtered, and rotary evaporated to obtain the product; 122 mg of the compound deuterated naphthalene, the yield was 90%, and the deuteration degrees were 95% and 90%. 1 H NMR (400 MHz, DMSO-d6) δ 7.92 (s, 0.20H), 7.51 (s, 0.40H).
[0039] Using the process conditions of Example 6, the corresponding deuterated products were formed by replacing the substrates: Deuterated toluene: The product mass was 81 mg, the yield was 84%, and the deuteration degree was 95%. 1 H NMR (400 MHz, DMSO-d6) δ 7.22–7.07 (m, 0.25H), 2.33 (d, J = 1.1 Hz, 3H). Deuterated anisole: The product mass was 107 mg, the yield was 95%, and the deuteration degree was 95%. 1 H NMR (400 MHz, Chloroform-d) δ 7.29–7.22 (m, 0.1H), 7.14–7.07 (m, 0.05H), 6.91–6.85 (m, 0.1H), 3.78 (s, 3H). Deuterated chlorobenzene: The product mass was 100 mg, the yield was 85%, and the deuteration degree was 94%. 1 H NMR (400 MHz, DMSO-d6) δ 7.50–7.07 (m, 0.3H). Deuterated bromobenzene: The product mass was 141 mg, the yield was 87%, and the deuteration degree was 95%. 11H NMR (400 MHz, DMSO-d6) δ 7.58–7.46 (m, 0.1H), 7.38–7.27 (m, 0.15H). Mesitylene-d12: Product mass 106 mg, yield 86%, deuterium incorporation 95%, 1 1H NMR (400 MHz, Chloroform-d) δ 6.84 (s, 0.15H), 2.25 (s, 9H). 2-Phenylpropan-2-ol-d1: Product mass 128 mg, yield 91%, deuterium incorporation 95%, 1 1H NMR (400 MHz, Chloroform-d) δ 7.32–7.20 (m, 0.25H), 3.59 (s, 1H), 1.51 (s, 6H). Acetophenone-d1: Product mass 119 mg, yield 95%, deuterium incorporation 92%, 1 1H NMR (400 MHz, Chloroform-d) δ 7.89–7.81 (m, 0.16H), 7.55–7.44 (m, 0.24H), 2.56 (s, 3H). Methyl benzoate-d1: Product mass 127 mg, yield 90%, deuterium incorporation 94%, 1 1H NMR (400 MHz, Chloroform-d) δ 7.99–7.93 (m, 0.12H), 7.54 (ddt, J = 8.2, 6.9, 1.5 Hz, 0.06H), 7.49–7.41 (m, 0.12H), 3.89 (s, 3H).
[0040] Under the process conditions of Example 9, replace the substrate to form the corresponding deuterated product: p-Nitrotoluene-d1: Product mass 127 mg, yield 90%, deuterium incorporation 90%, 1 1H NMR (400 MHz, Chloroform-d) δ 8.22–7.93 (m, 0.2H), 7.44–7.29 (m, 0.2H), 2.37 (d, J = 1.0 Hz, 3H). p-Toluidine-d1: Product mass 96 mg, yield 87%, deuterium incorporation 95%, 1 1H NMR (400 MHz, Chloroform-d) δ 7.12–6.92 (m, 0.1H), 6.69–6.47 (m, 0.1H), 4.11–3.91 (s, 2H), 2.35 (d, J = 0.9 Hz, 3H). Diphenylmethane-d2: Product mass 167 mg, yield 94%, deuterium incorporation 94%, 11H NMR (400 MHz, Chloroform-d) δ 7.31–7.19 (m, 0.6H), 3.94 (p, J=1.1 Hz, 2H). Deuterated anthracene: The product mass was 162 mg, the yield was 86%, and the deuteration degree was 96% / 92% / 90%. 1 1H NMR (400 MHz, DMSO-d6): δ 8.43 (s, 0.08H), 8.02 - 7.99 (m, 0.32H), 7.48 - 7.44 (m, 0.4H). Deuterated phenanthrene: The product mass was 169 mg, the yield was 90%, and the deuteration degree was 97% / 93% / 90% / 85%. 1 1H NMR (400 MHz, DMSO-d6) δ 8.18 (dd, J=8.2, 1.3 Hz, 0.06H), 8.04–7.99 (m, 0.14H), 7.91 (s, 0.2H), 7.58–7.50 (m, 0.6H). Deuterated fluorene: The product mass was 168 mg, the yield was 97%, and the deuteration degree was 95% / 93% / 90%. 1 1H NMR (400 MHz, Chloroform-d) δ 7.95–7.87 (m, 0.10H), 7.53–7.45 (m, 0.14H), 7.40–7.31 (m, 0.4H), 4.26–4.00 (m, 2H). Deuterated carbazole: The product mass was 159 mg, the yield was 91%, and the deuteration degree was 95% / 93% / 90%. 1 1H NMR (400 MHz, Chloroform-d) δ 10.2 (brs, 1H), 8.19–8.16 (m, 0.16H), 7.40–7.32 (m, 0.10H), 7.22–7.16 (m, 0.4H).
[0041] The above-described embodiments are only a preferred solution of the present invention and do not impose any form of limitation on the present invention. There are other variations and modifications without exceeding the technical solutions described in the claims.
Claims
1. A method for deuterating aromatic hydrocarbons catalyzed by La-doped Pd-CeO2 single atoms, characterized in that, Using aromatic hydrocarbons as raw materials, in an atmospheric pressure system, with or without the addition of a solvent, a deuteration reaction occurs with heavy water under the action of a La-doped Pd-CeO₂ single-atom catalyst. The reaction products are separated and purified to obtain deuterated products.
2. The method for deuterating aromatic hydrocarbons by La-doped Pd-CeO2 single-atom catalysis according to claim 1, wherein The aromatic hydrocarbon substrate is selected from one of benzene, toluene, anisole, chlorobenzene, bromobenzene, p-methylnitrobenzene, mesitylene, p-methylaniline, 2-phenylpropanol, diphenylmethane, acetophenone, methyl benzoate, naphthalene, anthracene, phenanthrene, fluorene, and carbazole; When the aromatic hydrocarbon is liquid, no solvent is added; when the aromatic hydrocarbon is solid, a solvent is added, and the amount of the solvent is the same volume as that of heavy water. The solvent is cyclohexane.
3. A method for deuterating aromatic hydrocarbons by La-doped Pd-CeO2 single-atom catalysis according to claim 1, characterized in that, The molar ratio of aromatic hydrocarbon: deuterium source reagent = 1:30 - 1:100; the dosage of the La-doped Pd-CeO₂ single-atom catalyst is 5 - 50% of the weight of the aromatic hydrocarbon.
4. A method for deuterating aromatic hydrocarbons by La-doped Pd-CeO2 single-atom catalysis according to claim 1, characterized in that, The deuteration reaction temperature is 60 - 100 °C, and the reaction time is 24 - 48 hours.
5. The method for deuterating aromatic hydrocarbons by La-doped Pd-CeO2 single-atom catalysis according to claim 1, wherein The preparation method of the La-doped Pd-CeO₂ single-atom catalyst is as follows: 1) Dissolve cerium salt and lanthanum salt in deionized water to form a mixed solution, then add citric acid and stir to form a complex. Then, slowly add ammonia water or sodium hydroxide solution to adjust the pH value to 7 - 9, and the solution forms a gel; dry the obtained gel to obtain a dry powder. Subsequently, transfer the dry powder to a high-temperature furnace and calcine it at 500 - 800 °C in an air atmosphere for 4 - 8 hours to obtain La-doped CeO₂ powder; 2) Add the La-doped CeO₂ powder to the palladium salt solution and stir evenly; then place it under a hydrogen atmosphere or use a reducing agent for reduction. After the reduction is completed, wash it clean with deionized water and dry it to obtain the La-doped Pd-CeO₂ single-atom catalyst.
6. A La-doped Pd-CeO2 single-atom catalyst, characterized in that, It is prepared through the following steps: 1) Dissolve cerium salt and lanthanum salt in deionized water to form a mixed solution, then add citric acid and stir to form a complex. Then, slowly add ammonia water or sodium hydroxide solution to adjust the pH value to 7 - 9, and the solution forms a gel; dry the obtained gel to obtain a dry powder. Subsequently, transfer the dry powder to a high-temperature furnace and calcine it at 500 - 800 °C in an air atmosphere for 4 - 8 hours to obtain La-doped CeO₂ powder; 2) Add the La-doped CeO₂ powder to the palladium salt solution and stir evenly; then place it under a hydrogen atmosphere or use a reducing agent for reduction. After the reduction is completed, wash it clean with deionized water and dry it to obtain the La-doped Pd-CeO₂ single-atom catalyst.
7. A method for deuterating aromatic hydrocarbons by La-doped Pd-CeO2 single-atom catalysis according to claim 5 or 6, characterized in that In step 1), the cerium salt is one of Ce(NO₃)₃, Ce(NO₃)₃·6H₂O, CeCl₃, CeCl₃·7H₂O; the lanthanum salt is one of La(NO₃)₃, La(NO₃)₃·6H₂O, LaCl₃, LaCl₃·7H₂O; The molar ratio of cerium ions to lanthanum ions is 1 - X∶X, where 0.1 ≤ X ≤ 0.
3. In the mixed solution, the total concentration of cerium ions and lanthanum ions is 0.1 - 1.0 mol / L.
8. A method for deuterating aromatic hydrocarbons catalyzed by La-doped Pd-CeO2 single atoms according to claim 5 or 6, characterized in that, The total molar amount of cerium salt and lanthanum salt: the molar amount of citric acid = 1:1 - 3.
9. A method for deuterating aromatic hydrocarbons catalyzed by La-doped Pd-CeO2 single atoms according to claim 5 or 6, characterized in that, In step 2), the palladium salt is sodium chloropalladate, potassium chloropalladate or ammonium chloropalladate, and the mass ratio of CeO2∶Pd = 4-6:
1.
10. A method for deuterating aromatic hydrocarbons catalyzed by La-doped Pd-CeO2 single atoms according to claim 5 or 6, characterized in that, In step 2), the reduction is carried out at a set temperature between 100 and 200 °C under a hydrogen atmosphere for 2 to 4 hours.