Catalyst as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of chemical synthesis, and particularly relates to a catalyst and a preparation method and application thereof. The catalyst comprises an active component, an auxiliary agent and a carrier, the active component is one or two of Rh and Pd, the auxiliary agent is one or more of Cr, Zn, Fe, Ru and In, and the carrier is modified ZSM-5; the weight fraction of the active metal component is 0.5%-10%, and the weight fraction of the auxiliary agent is 5%-30%. The noble metal active component is loaded on the surface of a specific carrier by adopting an improved impregnation method. The catalyst shows excellent deuterium directional binding capacity, and the preparation method is high in reliability, has universality and can be prepared and used on a large scale. The catalyst has high activity and deuterated ethanole-d6 selectivity for preparation of deuterated ethanole-d6 through deuterated conversion of saccharides, the deuterated rate of generated deuterated ethanol after rectification treatment is larger than or equal to 99.0%, and the catalyst has good application value.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical synthesis, and in particular relates to a catalyst, a preparation method and an application thereof. Background Art

[0002] Deuterated compounds are formed by replacing hydrogen atoms in a molecule with deuterium atoms, creating isotopically labeled derivatives. Their unique properties stem from the close similarity between deuterium and hydrogen in atomic radius and spatial configuration. This allows them to retain the biological activity of the parent molecule while also producing a significant deuterium kinetic isotope effect due to the shorter and more stable CD bond compared to the CH bond. This effect manifests as an increase in CD bond dissociation energy, leading to a decrease in metabolic rate, making them uniquely valuable in a variety of fields.

[0003] Deuterated ethanol (CD3CD2OD) is a typical example, possessing the dual attributes of a platform compound and a strategic reagent. In terms of industrial applications, this substance is both a key intermediate for deuterium-labeled macromolecular drugs and a core raw material for the synthesis of high-end functional materials. However, my country currently faces the dilemma of its preparation technology being constrained by human factors. Dependence on imports has led to high raw material costs, which has seriously restricted the development of related fields. The currently disclosed method for preparing deuterated ethanol is to utilize a hydrogen-deuterium (HD) exchange reaction. Using D2 or D2O as a deuterium source, the H atoms in CH3CH2OH are exchanged for D atoms under the action of a metal catalyst. Traditional hydrogen-deuterium exchange reactions may involve problems such as incomplete deuteration and complex product separation processes. Deuterated ethanol can also be produced through a fixed-bed synthesis gas reaction. Although the deuteration rate is guaranteed, side reactions may occur.

[0004] Biomass is considered the most promising new energy source to replace fossil resources due to its wide distribution, high yield, and pollution-free nature, as well as being the only recyclable carbon resource. The production of chemicals such as deuterated ethanol from biomass has attracted increasing attention. Deuterated ethanol production from sugars (glucose, xylose, etc.) produced by plants grown in deuterium water ensures an overall deuteration rate while avoiding negative reactions and the significant waste of deuterium in hydrogen-deuterium exchange reactions. This holds great potential for the efficient production of deuterated ethanol, but a specialized, efficient catalyst has been lacking. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a catalyst and its preparation method and application, which can be applied to the reaction of synthesizing deuterated ethanol-d6 using mixed sugar solution as raw material. The technical solution adopted is:

[0006] A catalyst comprises an active component, an auxiliary agent and a carrier, wherein the active component is one or two of Rh and Pd, the auxiliary agent is one or more of Cr, Zn, Fe, Ru and In, and the carrier is modified ZSM-5; the weight fraction of the active metal component is 0.5%-10%, and the weight fraction of the auxiliary agent is 5%-30%.

[0007] A method for preparing a catalyst comprises the following steps:

[0008] 1) dissolving an active metal component precursor and an auxiliary component precursor in a water-ethanol mixed solution to prepare a mixed precursor solution;

[0009] 2) taking a carrier, adding the above mixed precursor solution dropwise therein, and ball milling;

[0010] 3) When the mixture becomes viscous, the mixture is transferred to a vacuum oven for drying; the sample is then calcined in a tube furnace to obtain a catalyst.

[0011] Preferably, in step 1), the active metal component precursor is any one of rhodium nitrate and palladium nitrate.

[0012] Preferably, in step 1), the auxiliary component precursor is any one or more of Cr nitrate, Zn acetate, Fe nitrate, Ru chloride, and In nitrate; and the modified ZSM-5 is HZSM-5, i.e., hydrogen-modified ZSM-5. The ZSM-5 molecular sieve is ion-exchanged with an ammonium salt solution to remove sodium ions and introduce hydrogen ions. Subsequently, physically adsorbed moisture and organic templates are removed through steps such as calcination to obtain the final HZSM-5 molecular sieve.

[0013] Preferably, in step 2), the ball milling conditions are those conventionally set in the prior art, and the ball milling time is 1-3 hours.

[0014] Preferably, in step 3), the calcination temperature is 300-600°C and the calcination time is 3-6 hours.

[0015] Preferably, the heating rate during calcination is 1-10°C / min, and the atmosphere used is 10% H2 / Ar.

[0016] The catalyst prepared by the method of the present invention is used in the direct synthesis of deuterated ethanol-d6 from a deuterated mixed sugar solution. A mixture of deuterated sugars produced by plants with a mass content of 0.5-5 g / L is dissolved in deuterium water, stirred evenly, and then transferred to a high-pressure reactor. The deuterated ethanol-d6 reaction is carried out under a hydrogen atmosphere of 3-6 MPa.

[0017] Preferably, the mixture of deuterated sugars is any one or more of glucose, xylose and fructose.

[0018] Preferably, the reaction time is 12-36 h, the temperature is 200-250° C., and the stirring speed is 300-800 rpm.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The dedicated catalyst system provided by this invention uses deuterated mixed sugar compounds and deuterated water (D2O) as starting materials in the direct synthesis of deuterated ethanol (d6) from a deuterated mixed sugar solution. The target product is produced through a thermal catalytic reaction under high temperature and high pressure. Targeting the characteristics of this synthesis process, this patent innovatively develops an adapted noble metal catalyst and its preparation process: an improved impregnation method is used to load the noble metal active component onto a specific support surface. This catalyst not only exhibits excellent directional deuterium binding ability but also achieves high selectivity for deuterated ethanol.

[0021] The catalyst preparation method of the present invention is highly reliable and universally applicable, allowing for large-scale production and use. The catalyst exhibits high activity and selectivity for the deuterated conversion of carbohydrates to produce deuterated ethanol-d6. The generated deuterated ethanol exhibits a deuteration rate of ≥99.0% after distillation, demonstrating excellent application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a flow chart of the preparation method of the present invention.

[0023] Figure 2 This is the selectivity distribution diagram of the catalyst prepared in Example 4 of the present invention after reaction. DETAILED DESCRIPTION

[0024] The present invention will be further described below with reference to specific examples, but the scope of the present invention is not limited thereto. The chemical reagents used in the present invention can be purchased through conventional commercial channels unless otherwise specified, and the detection or testing methods can be detected or tested according to conventional methods unless otherwise specified.

[0025] Example 1

[0026] like Figure 1 As shown, a method for preparing a catalyst comprises the following steps:

[0027] Weigh 5.7 mL of palladium nitrate solution (9 g Pd / L) and 0.71g of chromium nitrate powder were dissolved in 15mL of deionized water to prepare a mixed precursor solution. Then, 1g of ZSM-5 was weighed, and the mixed precursor solution was added dropwise to the mixture, followed by ball milling for 1.2 hours. The paste was then transferred to a 100°C oven for drying for 12 hours. The sample was then calcined in a tube furnace at 500°C for 3 hours at a heating rate of 1°C / min to obtain a Pd-Cr / ZSM-5 catalyst containing 4.5% by weight of the active metal component Pd and 8% by weight of the additive Cr.

[0028] Example 2

[0029] A method for preparing a catalyst comprises the following steps:

[0030] Weigh 3.6 mL of rhodium nitrate solution (5 g Rh / L -1 ) and 0.9g zinc acetate powder were dissolved in 13mL of deionized water to prepare a mixed precursor solution. 1.5g of ZSM-5 was then weighed and added dropwise to the mixed precursor solution, followed by ball milling for 1.5 hours. The paste was then dried in a 100°C oven for 12 hours and calcined in a tube furnace at 600°C for 4 hours at a heating rate of 5°C / min to obtain a Rh-Zn / ZSM-5 catalyst. The active metal component Rh contained 1% by weight, and the additive Zn contained 15% by weight.

[0031] Example 3

[0032] A method for preparing a catalyst comprises the following steps:

[0033] Weigh 6.4 mL of palladium nitrate solution (9 g Pd / L -1 ) and 2.4g of ferric nitrate (0.0045mol) were dissolved in 15mL of deionized water to prepare a mixed precursor solution; then 1.25g of ZSM-5 was weighed, the mixed precursor solution was added dropwise thereto, and ball milled for 3h. The paste was then transferred to a 100°C oven for drying for 12h, and the sample was placed in a tube furnace and calcined at 350°C for 6h with a heating rate of 10°C / min to obtain a Pd-Fe / ZSM-5 catalyst. The weight percentage of the active metal component Pd was 3.5%, and the weight percentage of the auxiliary agent Fe was 20%.

[0034] Example 4

[0035] A method for preparing a catalyst comprises the following steps:

[0036] Weigh 4.1 mL of rhodium nitrate solution (5 g Rh / L -1 ) and 13.5 mL of ruthenium chloride solution (10 g Rh / L -1 ) was dissolved in 10 mL of deionized water to prepare a mixed precursor solution. 1.2 g of ZSM-5 was then weighed, the mixed precursor solution was added dropwise, and ball-milled for 2 hours. The paste was then transferred to a 100°C oven for drying for 12 hours. The sample was then calcined in a tube furnace at 300°C for 6 hours at a heating rate of 2°C / min to obtain a Rh-Ru / ZSM-5 catalyst. The weight percentage of the active metal component Rh was 1.5%, and the weight percentage of the additive Ru was 10%.

[0037] Example 5

[0038] A method for preparing a catalyst comprises the following steps:

[0039] Weigh 28mL of rhodium nitrate solution (5g Rh / L -1 ) and 1.9g indium nitrate solution (0.05gm) were dissolved in 10ml deionized water to prepare a mixed precursor solution; then 1.3g ZSM-5 was weighed, the mixed precursor solution was added dropwise thereto, and ball milled for 5h. The paste was then transferred to a 100°C oven for drying for 12h, and the sample was placed in a tube furnace and calcined at 450°C for 6h with a heating rate of 1°C / min to obtain a Rh-In / ZSM-5 catalyst. The weight percentage of the active metal component Rh is 7.3%, and the weight percentage of the auxiliary agent In is 25%.

[0040] Example 6

[0041] A method for preparing a catalyst comprises the following steps:

[0042] The catalyst and sugar mixture was added to an autoclave, followed by 80 mL of deuterated water. The mixture was stirred for 5 minutes. The atmosphere was then displaced with high-purity hydrogen three times at 2 MPa and three times at 5 MPa. The pressure was then increased to 5 MPa, equilibrated for 20 minutes, and then reacted at this pressure for 12 hours at 230°C and 600 rpm. After the reaction, the mixture was cooled to 10°C in an ice-water bath, and the reacted liquid was collected.

[0043] The properties of the target product, deuterated ethanol (d6), prepared using the catalyst of Example 4 were analyzed. The reaction exhaust was collected using a custom-made collector, and the reaction products were analyzed using a liquid chromatograph (Agilent 1260) equipped with a RID detector (Metacarb 87H column, 300 mm × 7.8 mm).

[0044] After distillation and separation, the product is analyzed. The test results are as follows Figure 2 shown.

[0045] from Figure 2 It can be seen that the catalyst has relatively high activity and deuterated ethanol selectivity, with a sugar conversion rate of 100% and an ethanol yield of 65%. When the catalyst of this embodiment is used to directly synthesize deuterated ethanol-d6 from a deuterated mixed sugar solution, the ethanol deuteration rate is 99.2%.

[0046] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the scope of protection of the present invention.

Claims

1. A catalyst, characterized in that The invention comprises an active component, an auxiliary agent and a carrier, wherein the active component is one or two of Rh and Pd, the auxiliary agent is one or more of Cr, Zn, Fe, Ru and In, and the carrier is modified ZSM-5; the weight fraction of the active metal component is 0.5%-10%, and the weight fraction of the auxiliary agent is 5%-30%.

2. The method for preparing a catalyst according to claim 1, wherein: The specific steps include: 1) dissolving an active metal component precursor and an auxiliary component precursor in a water-ethanol mixed solution to prepare a mixed precursor solution; 2) Take a carrier and drop the above mixed precursor solution into it. and ball milling; 3) ball milling the mixture until it becomes viscous and then transferring it to a vacuum oven for drying; The sample was then calcined in a tube furnace to obtain the catalyst.

3. The method for preparing a catalyst according to claim 2, wherein: In the step 1), the active metal component precursor is any one of rhodium nitrate and palladium nitrate.

4. The method for preparing a catalyst according to claim 2, wherein: In the step 1), the auxiliary component precursor is any one or more of Cr nitrate, Zn acetate, Fe nitrate, Ru chloride, and In nitrate; and the modified ZSM-5 is HZSM-5.

5. The method for preparing a catalyst according to claim 2, wherein: In the step 2), the ball milling time is 1-3 hours.

6. The method for preparing a catalyst according to claim 2, wherein: In the step 3), the calcination temperature is 300-600° C. and the calcination time is 3-6 hours.

7. The method for preparing a catalyst according to claim 6, characterized in that: The heating rate during calcination is 1-10°C / min, and the atmosphere used is 10% H2 / Ar.

8. Use of the catalyst prepared by the method according to any one of claims 2 to 7 in the direct synthesis of deuterated ethanol-d6 from a deuterated mixed sugar solution, characterized in that: A mixture of deuterated sugars produced by plants with a mass content of 0.5-5 g / L is dissolved in deuterated water, stirred evenly, and then transferred to a high-pressure reactor to carry out a deuterated ethanol-d6 reaction under a hydrogen atmosphere of 3-6 MPa.

9. Use according to claim 8, characterized in that The deuterated sugar mixture is any one or more of glucose, xylose and fructose.

10. The use according to claim 8, characterized in that The reaction time is 12-36 hours, the temperature is 200-250°C, and the stirring speed is 300-800 rpm.

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