A ruthenium-based catalyst, its preparation method and use

Abstract

The application discloses a ruthenium-based catalyst and a preparation method and application thereof. The catalyst is prepared by embedding ruthenium into polyaniline with phytic acid as a medium and then pyrolyzing. The application adds hexamethylene diamine and deuterium water into a high-pressure reaction kettle, adds a catalyst and carries out catalytic reaction in a hydrogen atmosphere, and high deuterium substitution rate hexamethylene diamine is obtained. Through the coordination of phytic acid and ruthenium, the ruthenium is highly dispersed on the surface of polyaniline and exposes a large number of active sites. The pyrolysis temperature is controlled to control the electronic structure of ruthenium and improve the catalyst activity, so that the prepared hexamethylene diamine has a high deuterium incorporation amount. The ruthenium-based thermal catalyst has an alpha-H deuterium incorporation rate of 1,6-hexamethylene diamine up to 95.62%, and the catalyst also has good thermal catalytic stability, and shows certain practical application potential.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of material preparation, and particularly relates to a ruthenium-based catalyst and a preparation method and application thereof. BACKGROUND

[0002] Deuterated compounds play a crucial role and have immeasurable potential in analytical chemistry, medicinal chemistry and material science. Perdeuterated 1,6-hexanediamine can be used to label biological macromolecules such as proteins, nucleic acids and polysaccharides to study their biological functions and metabolic pathways. Therefore, it is of great significance to use 1,6-hexanediamine as a research object to explore the deuteration reaction system of main amine compounds.

[0003] Traditional deuteration strategies can be divided into three categories according to the overall conversion of the reaction: reduction and deuteration, dehalogenation and deuteration, and hydrogen-deuterium exchange. Among them, the hydrogen-deuterium exchange reaction can directly label the target molecule with D2O or D2, which significantly saves the time and cost of synthesis. At present, the preparation of deuterated compounds by hydrogen-deuterium exchange mainly uses the C-H bond activation strategy catalyzed by transition metals, but there are problems such as expensive deuterium source, low deuterium incorporation rate, harsh reaction conditions, and low utilization rate of deuterium source. SUMMARY

[0004] In view of the above technical problems existing in the prior art, the purpose of the present application is to provide a ruthenium-based catalyst and a preparation method and application thereof. The preparation method of the catalyst of the present application is to use a simple two-step coordination and high-temperature calcination method, to disperse ruthenium on the surface of polyaniline by coordination of phytic acid and ruthenium and in-situ phosphatization, to control the electronic structure of ruthenium and expose a large number of active sites, and to synthesize a catalyst with high deuterium incorporation for thermal catalytic hexanediamine hydrogen-deuterium exchange.

[0005] The technical scheme adopted by the present application is as follows:

[0006] A ruthenium-based catalyst, which is formed by coordinating phytic acid with ruthenium to form a ruthenium complex Ru-PA, then mixing and stirring the complex Ru-PA with polyaniline in an aqueous solution to dope it into polyaniline, then filtering and drying, and then pyrolyzing the solid product at high temperature to make ruthenium uniformly and stably distributed on the surface of polyaniline and in-situ phosphatization, while polyaniline is pyrolyzed into carbon material to obtain the ruthenium-based catalyst.

[0007] The ruthenium-based catalyst and the preparation method thereof specifically include the following steps:

[0008] 1) Disperse ruthenium salt and phytic acid in deionized water, heat and reflux and stir to form an aqueous solution containing ruthenium complex Ru-PA, denoted as Ru-PA coordination solution;

[0009] 2) dispersing aniline and p-phenylenediamine in deionized water, adding ammonium persulfate aqueous solution drop by drop in a low temperature environment to make them polymerize to obtain a polyaniline solution;

[0010] 3) adding the Ru-PA coordination solution obtained in step 1) into the polyaniline solution obtained in step 2) after low temperature treatment, stirring to make the ruthenium complex Ru-PA doped into polyaniline, and finally filtering and drying the obtained suspension to obtain black Ru-PA-PANI powder;

[0011] 4) transferring the black Ru-PA-PANI powder obtained in step 3) into a tube furnace to calcine and pyrolyze the sample at high temperature to obtain a ruthenium-based catalyst, which is recorded as Ru x / NPC-y (x represents the molar ratio of ruthenium element to phytic acid, and y represents the pyrolysis temperature).

[0012] Further, in step 1), the molar ratio of Ru element in the ruthenium salt to phytic acid is 1-5:1, preferably 4:1, the temperature of heating reflux is 80-95℃, preferably 85-90℃, and the time of heating reflux is 5-20h, preferably 8-10h.

[0013] Further, in step 2), the molar ratio of aniline to p-phenylenediamine is 60-80:1, preferably 70-75:1, and the molar ratio of aniline to ammonium persulfate is 3-6:1, preferably 4-5:1.

[0014] Further, in step 2), the polymerization reaction is carried out at 3-5℃ for 3-5h.

[0015] Further, in step 1), the mass of Ru element in the ruthenium salt is 0.2-1.0% of the mass of aniline in step 2), preferably 0.5-0.6%.

[0016] Further, in step 3), the process of low temperature treatment of the Ru-PA coordination solution is to reduce the temperature to 3-5℃.

[0017] Further, in step 4), the calcination is carried out in a nitrogen atmosphere, the calcination temperature is 500-900℃, preferably 600℃, the calcination time is 2-10h, preferably 5-6h, and then the sample is naturally cooled to room temperature.

[0018] The application also provides the application of the phytic acid doped polyaniline coordinated ruthenium catalyst in hydrogen-deuterium exchange reaction.

[0019] Further, the catalyst is used to catalyze the hydrogen-deuterium exchange reaction of hexamethylene diamine, the catalyst, hexamethylene diamine and deuterium water are added into a high-pressure reaction kettle, after the air is replaced by hydrogen, a certain pressure of hydrogen is filled for stirring reaction, the feeding ratio of the catalyst and hexamethylene diamine is 30-50 mg: 1 mmol, preferably 40 mg: 1 mmol, the molar ratio of deuterium in deuterium water to hydrogen in hexamethylene diamine is 15-30: 1, preferably 20-25: 1. The hydrogen pressure is 1-2 MPa, the reaction temperature is 100-120 DEG C, the reaction time is 5-6 h, and the stirring speed is 300-600 r / min.

[0020] Compared with the prior art, the present application has the beneficial effects that:

[0021] 1) The raw material in the preparation of the catalyst is easy to obtain, has low toxicity, is low in cost, and has simple preparation steps and good repeatability;

[0022] 2) The reaction conditions are relatively mild, and the preparation process has few safety hazards;

[0023] 3) The ruthenium-based (Ru / NPC) thermal catalyst prepared by the above-mentioned technology has a high 1,6-hexanediamine alpha-H deuterium incorporation rate of 95.62%, and in addition, the catalyst also has good thermal catalytic stability, and shows certain practical application potential. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The SEM image of the phytic acid doped polyaniline complex ruthenium (Ru / NPC-600) thermal catalyst obtained in Example 1 of the present application;

[0025] Figure 2 The reaction liquid for the catalytic reaction of the phytic acid doped polyaniline complex ruthenium (Ru4 / NPC-600) thermal catalyst obtained in Example 1 of the present application; 1 The HNMR nuclear magnetic resonance test result, which measures the signal of hydrogen, the weaker the signal, the higher the deuterium substitution rate.

[0026] Figure 3 The stability test result graph of the phytic acid doped polyaniline complex ruthenium (Ru4 / NPC-600) thermal catalyst obtained in Example 1 of the present application. DETAILED DESCRIPTION

[0027] The present application will be described in detail below in conjunction with specific embodiments, but the protection scope of the present application is not limited thereto.

[0028] Example 1: A preparation method of a ruthenium-based catalyst (Ru / NPC) is as follows:

[0029] 1) Dissolve 100 mg of ruthenium trichloride in 50 mL of deionized water, add 137 mg of phytic acid, and stir at 90°C for 10 h to form a wine red suspension, which is a phytic acid complex ruthenium solution.

[0030] 2) Take the phytic acid complex ruthenium solution prepared in 1) and perform low-temperature treatment (cool to 5°C), weigh 2 mL of aniline and 33 mg of p-phenylenediamine, and disperse them in 50 mL of deionized water and perform low-temperature treatment. When the temperature is below 5°C, add 5 mL of an aqueous ammonium persulfate solution (200 mg / mL), stir at 500 rpm for 30 min, then add 10 mL of the phytic acid complex ruthenium prepared in Example 1 (containing 9.76 mg of ruthenium element), stir for 2 h, filter, and vacuum dry at 70°C for 12 h to obtain a Ru-PA-PANI powder. Place the obtained precursor in a tube furnace and perform high-temperature calcination at 600°C under a nitrogen atmosphere for 5 h to obtain a ruthenium-based thermal catalyst, which is recorded as Ru4 / NPC-600.

[0031] The SEM image of the catalyst Ru4 / NPC-600 obtained in Example 1 is shown in Figure 1 .

[0032] Examples 2-5: A preparation method of a ruthenium-based catalyst prepared with different amounts of phytic acid doping is as follows:

[0033] The difference between the preparation method and Example 1 is that the amount of phytic acid added when preparing the phytic acid complex ruthenium solution is 548 mg, 274 mg, 183 mg, and 110 mg, respectively, and the molar ratio of ruthenium element in the ruthenium salt to phytic acid is 1:1, 2:1, 3:1, and 5:1, respectively, which is recorded as Ru x / NPC-600 (x represents the molar ratio of ruthenium to phytic acid).

[0034] Example 6: A preparation method of a ruthenium-based catalyst without adding phytic acid is as follows:

[0035] The difference between the preparation method and Example 1 is that the ruthenium-based catalyst obtained without adding phytic acid in the preparation process is recorded as Ru / NC-600.

[0036] Example 7: A preparation method of a ruthenium-based catalyst without adding phytic acid and p-phenylenediamine is as follows:

[0037] The difference between the preparation method and Example 1 is that the ruthenium-based catalyst obtained without adding phytic acid and p-phenylenediamine in the preparation process is recorded as Ru4 / NC0-600.

[0038] Examples 8-11: A preparation method of a ruthenium-based thermal catalyst (Ru4 / NPC-y, y represents the calcination temperature) calcined at 500°C and 700-900°C is as follows:

[0039] The Ru-PA-PANI powder prepared in Example 1 was calcined at 500°C and 700-900°C for 4h in nitrogen atmosphere, respectively, and then naturally cooled to room temperature to obtain a ruthenium-based thermal catalyst.

[0040] The specific thermal catalytic hexamethylene diamine hydrogen-deuterium exchange performance test will be specifically described in the application examples.

[0041] Application Example 1: Catalytic hexamethylene diamine hydrogen-deuterium exchange performance test steps:

[0042] 1) 20 mg of catalyst was added to a high-pressure reaction kettle, 0.5 mmol of hexamethylene diamine and 1 mL of deuterium water were added;

[0043] 2) After replacing the air in the high-pressure reaction kettle with hydrogen twice, 2 MPa of hydrogen was injected, and the reaction was carried out at 100°C and a stirring rate of 500 r / min for 5h, and the sample was analyzed.

[0044] When the catalysts of Examples 1-11 were used to test the catalytic hexamethylene diamine hydrogen-deuterium exchange performance according to the above steps, the test results were as shown in Table 1, taking the total deuterium incorporation rate of the hexamethylene diamine hydrogen-deuterium exchange reaction as the index, and taking 100% as the theoretical upper limit value. Among them, when the product after the reaction of Example 1 catalyst was separated and redissolved with deuterium water as the solvent, 1,4-dioxane was added as the internal standard for nuclear magnetic testing, and the results were as shown in Figure 2 .

[0045] Table 1

[0046] Catalyst Total deuterium incorporation (%) Example 1 [Ru4 / NPC-600] 91.70 Example 2 <![CDATA[Ru1 / NPC-600]]> 54.77 Example 3 <![CDATA[Ru2 / NPC-600]]> 65.22 Example 4 [Ru3 / NPC-600] 83.47 Example 5 <![CDATA[Ru5 / NPC-600]]> 74.06 Example 6 Ru / NC-600 27.59 Example 7 [Ru / NC 0-600] 13.00 Example 8 <![CDATA[Ru4 / NPC-500]]> 27.60 Example 9 [Ru4 / NPC-700] 60.13 Example 10 <![CDATA[Ru4 / NPC-800]]> 51.05 Example 11 <![CDATA[Ru4 / NPC-900]]> 38.20

[0047] As to the thermal catalytic hydrogen-deuterium exchange reaction of hexanediamine, the total deuterium incorporation rate is taken as the main thermal catalytic performance evaluation index, and the long-time stability is also a high performance embodiment of the thermal catalyst. According to the summary of the performance of the prepared ruthenium-based thermal catalyst (Ru / NPC) in Table 1, it is found that, by comparing Example 1 to Example 6, the phytic acid doping can effectively improve the catalytic activity of the catalyst for the hydrogen-deuterium exchange of hexanediamine, and there is a large difference between the performances of the catalysts prepared under different phytic acid doping amounts. The catalyst prepared when the molar ratio of ruthenium in the ruthenium salt to phytic acid is 4:1: has the best catalytic performance, and the reason may be that the appropriate amount of phytic acid doping can make the active metal more uniformly dispersed (for example, if the amount of phytic acid is too large, a part of the free phytic acid grafted to the polyaniline carrier will not be grafted to the polyaniline carrier, causing part of the ruthenium to be lost during the preparation of the catalyst, and reducing the activity of the catalyst). It can be known by comparing Example 6 and Example 7 that the addition of p-phenylenediamine for preparing the catalyst can improve the catalytic performance of the catalyst, and the reason may be that the polyaniline synthesized by adding p-phenylenediamine is more disordered, and can form a certain three-dimensional spatial structure. By comparing Example 1 and Example 8 to Example 11, it is found that there is a large difference between the performances of the catalysts prepared under different calcination conditions, and the reason is that the different pyrolysis temperatures lead to different physical structures and chemical states of the active components of the catalysts. When the nitrogen calcination temperature is 600°C, the performance of the Ru / NPC-600 catalyst prepared reaches the optimum among the tested catalysts (total deuterium substitution rate: 91.70%), and after 5 times of stability test, the performance does not obviously decrease (see the stability test results of the phytic acid-doped polyaniline coordinated ruthenium (Ru4 / NPC-600) thermal catalyst obtained in Example 1 of the present application). Figure 3 The stability test results of the phytic acid-doped polyaniline coordinated ruthenium (Ru4 / NPC-600) thermal catalyst obtained in Example 1 of the present application show that the ruthenium-based thermal catalyst (Ru / NPC) of the present application has excellent catalytic activity for the hydrogen-deuterium exchange reaction of 1,6-hexanediamine, and can achieve a high deuterium substitution rate, and has very excellent stability.

[0048] The content described in the specification is only a list of implementation forms of the inventive concept, and the protection scope of the present application should not be regarded as limited to the specific forms stated in the examples.

Claims

1. Application of a ruthenium-based catalyst in a hydrogen-deuterium exchange reaction, characterized in that The catalyst forms a ruthenium complex Ru-PA by coordinating phytic acid with ruthenium. The complex Ru-PA is then mixed and stirred with polyaniline in an aqueous solution to be doped into the polyaniline. The mixture is then filtered and dried. The solid product is then pyrolyzed at high temperature to uniformly and stably distribute ruthenium on the surface of the polyaniline and in-situ phosphating the polyaniline. Simultaneously, the polyaniline is pyrolyzed into a carbon material to obtain a ruthenium-doped carbon material catalyst.

2. The use according to claim 1, characterized in that The preparation method of the ruthenium-based catalyst comprises the following steps: 1) Dispersing ruthenium salt and phytic acid in deionized water, heating under reflux and stirring to form an aqueous solution containing a ruthenium complex Ru-PA, which is referred to as the Ru-PA coordination solution; 2) Aniline and p-phenylenediamine are dispersed in deionized water, and an aqueous ammonium persulfate solution is added dropwise at low temperature to polymerize the mixture to obtain a polyaniline solution; 3) The Ru-PA coordination solution obtained in step 1) is added to the polyaniline solution obtained in step 2) after low-temperature treatment, and stirred to dope the ruthenium complex Ru-PA into the polyaniline. Finally, the resulting suspension is filtered and dried to obtain a black Ru-PA-PANI powder; 4) The black Ru-PA-PANI powder obtained in step 3) is transferred to a tube furnace for calcination, and the sample is subjected to high-temperature pyrolysis to obtain a ruthenium-based catalyst.

3. The use according to claim 2, characterized in that The molar ratio of Ru element to phytic acid in the ruthenium salt in step 1) is 3-5:1, the heating reflux temperature is 80-95° C., and the heating reflux time is 5-20 hours.

4. The use according to claim 3, characterized in that The molar ratio of Ru element to phytic acid in the ruthenium salt in step 1) is 4:1, the heating reflux temperature is 85-90° C., and the heating reflux time is 8-10 hours.

5. The use according to claim 2, characterized in that In step 2), the molar ratio of aniline to p-phenylenediamine is 60-80:1, and the molar ratio of aniline to ammonium persulfate is 3-6:

1.

6. The use according to claim 5, characterized in that In step 2), the molar ratio of aniline to p-phenylenediamine is 70-75:1, and the molar ratio of aniline to ammonium persulfate is 4-5:

1.

7. The use according to claim 2, characterized in that In step 2), the polymerization reaction is carried out at a temperature of 3-5°C for 3-5 hours. In step 3), the low-temperature treatment process of the Ru-PA coordination solution is to cool the solution to 3-5°C.

8. The use according to claim 2, characterized in that The mass of the Ru element in the ruthenium salt in step 1) is 0.2-1.0% of the mass of the aniline in step 2).

9. The use according to claim 8, characterized in that The mass of the Ru element in the ruthenium salt in step 1) is 0.5-0.6% of the mass of the aniline in step 2).

10. The use according to claim 2, characterized in that The calcination in step 4) is carried out in a nitrogen atmosphere at a temperature of 500-900° C. for 2-10 hours, followed by natural cooling to room temperature.

11. The use according to claim 10, characterized in that The calcination in step 4) is performed at a temperature of 800° C. and for a time of 5-6 hours.

12. The use according to claim 1, characterized in that The catalyst is used to catalyze the hydrogen-deuterium exchange reaction of hexamethylenediamine. The catalyst, hexamethylenediamine and deuterium water are added to a high-pressure reactor. After the air is replaced by hydrogen, hydrogen at a certain pressure is introduced for stirring reaction. The feed ratio of the catalyst to hexamethylenediamine is 30-50 mg:1 mmol, and the molar ratio of deuterium in the deuterium water to hydrogen in the hexamethylenediamine is 15-30:

1.

13. The use according to claim 12, characterized in that The feed ratio of the catalyst to hexamethylenediamine is 40 mg:1 mmol, and the molar ratio of deuterium in deuterium water to hydrogen in hexamethylenediamine is 20-25:

1.

14. The use according to claim 12, characterized in that The hydrogen pressure is 1~2MPa, the reaction temperature is 100~120℃, the reaction time is 5~6h, and the stirring speed is 300-600r / min.

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