阅读说明：本技术 一种乙基纤维素衍生的铁掺杂碳材料及其制备方法和应用 (Iron-doped carbon material derived from ethyl cellulose and preparation method and application thereof ) 是由 黄和 林雅玫 张幸 王飞 于 2021-08-20 设计创作，主要内容包括：本发明公开了一种乙基纤维素衍生的铁掺杂碳材料及其制备方法和应用,其包括如下步骤：(1)将乙基纤维素加热溶解于无水乙醇中配成第一溶液,将Fe(NO-(3))-(3)·9H-(2)O和2,2′-联吡啶的混合物溶解于无水乙醇中配成第二溶液,第一溶液和第二溶液进行混合,反应得混合液；(2)将氮源和锌源粉末添加到步骤(1)所得的混合液中,蒸干溶剂得到固体后干燥；(3)将步骤(2)所得固体在惰性气体氛围下煅烧,得到乙基纤维素衍生的铁掺杂碳材料。按照上述方法制备得到的碳材料作为催化剂被用于催化N-H卡宾插入反应,制备非天然氨基酸衍生物。和已有催化剂相比,该催化剂具有更好的活性、选择性和稳定性,且催化效率高,重复利用性好。(The invention discloses an iron-doped carbon material derived from ethyl cellulose, a preparation method and application thereof, wherein the preparation method comprises the following steps: (1) heating ethyl cellulose to dissolve in anhydrous ethanol to obtain first solution, and dissolving Fe (NO) 3 ) 3 ·9H 2 Dissolving a mixture of O and 2, 2' -bipyridyl in absolute ethyl alcohol to prepare a second solution, mixing the first solution and the second solution, and reacting to obtain a mixed solution; (2) adding a nitrogen source and zinc source powder into the mixed solution obtained in the step (1), evaporating the solvent to obtain a solid, and drying; (3) and (3) calcining the solid obtained in the step (2) in an inert gas atmosphere to obtain the iron-doped carbon material derived from the ethyl cellulose. Prepared according to the methodThe obtained carbon material is used as a catalyst to catalyze N-H carbene insertion reaction to prepare the unnatural amino acid derivative. Compared with the existing catalyst, the catalyst has better activity, selectivity and stability, high catalytic efficiency and good reutilization property.)

1. An ethylcellulose-derived iron-doped carbon material, characterized by comprising as the carbon material, carbonized ethylcellulose, an element of nitrogen, an element of zinc, iron present in the form of particles; the iron particles are surrounded by a porous carbon material, nitrogen element is doped into the carbon material, and the whole surface has spherical aggregate particles.

2. The ethylcellulose-derived iron-doped carbon material of claim 1, wherein the iron particles are predominantly Fe₂O₃FeO, and Fe.

3. The ethylcellulose-derived iron-doped carbon material of claim 1, wherein the carbon material is a graphitic carbon structure.

4. A method of preparing an ethylcellulose-derived iron-doped carbon material as claimed in claim 1, characterized in that it comprises the steps of:

(1) heating ethyl cellulose to dissolve in anhydrous ethanol to obtain first solution, and dissolving Fe (NO)₃)₃·9H₂Dissolving a mixture of O and 2, 2' -bipyridyl in absolute ethyl alcohol to prepare a second solution, mixing the first solution and the second solution, and reacting to obtain a mixed solution;

(2) adding a nitrogen source and zinc source powder into the mixed solution obtained in the step (1), evaporating the solvent to obtain a solid, and drying;

(3) and (3) calcining the solid obtained in the step (2) in an inert gas atmosphere to obtain the iron-doped carbon material derived from the ethyl cellulose.

5. The method for producing an ethylcellulose-derived iron-doped carbon material as claimed in claim 4, wherein said heating temperature in step (1) is 70-90 ℃; fe (NO)₃)₃·9H₂The feeding molar ratio of O to 2, 2' -bipyridine is 1: 1-1: 2.

6. The method for producing an ethylcellulose-derived iron-doped carbon material according to claim 4, wherein said nitrogen source in step (2) is melamine; the zinc source is zinc nitrate hexahydrate; the drying temperature is 55-65 ℃.

7. The method for producing an ethylcellulose-derived iron-doped carbon material according to claim 4, wherein the inert gas in the step (3) is nitrogen or argon; the calcination is carried out at 800-1000 ℃; in the calcining process, the heating rate is 3-8 ℃/min, and the calcining time is 2-3 h.

8. Use of the ethylcellulose-derived iron-doped carbon material as described in claim 1 for catalyzing N-H carbene insertion reactions.

9. Use of the ethylcellulose-derived iron-doped carbon material as claimed in claim 1 for the preparation of non-natural amino acid derivatives.

10. Use according to any one of claims 8-9, characterized in that it comprises the following steps: adding amine, an iron-doped carbon material derived from ethyl cellulose, ethyl diazoacetate and a solvent into a reaction container, sealing the reaction container under the condition of normal pressure and nitrogen, reacting at room temperature, after the reaction is finished, centrifugally separating the iron-doped carbon material derived from ethyl cellulose as a catalyst, removing an organic phase by rotary evaporation to obtain a crude product, and finally separating and purifying by column chromatography to obtain the target product.

Technical Field

The invention relates to a catalyst, a preparation method and application thereof, in particular to an iron-doped carbon material derived from ethyl cellulose, and a preparation method and application thereof.

Background

N-H carbene insertion of amines with ethyl diazoacetate is a powerful tool for the formation of alpha-amino acid esters, which are key intermediates for the synthesis of pharmaceuticals, agrochemicals and natural products. Homogeneous catalytic systems for catalyzing N-H carbene insertion reactions have been greatly developed over the past decades, but most of these homogeneous catalytic systems suffer from problems of catalyst recovery and product separation. Compared with homogeneous catalysts, heterogeneous catalysts have the advantages of stability, recoverability, environmental protection and the like. Furthermore, the introduction of inexpensive transition metals into heterogeneous catalysts would be more consistent with the concept of sustainable development.

Part of the research reports that heterogeneous catalysts with cheap transition metals as active centers are used for catalyzing N-H carbene insertion reactions, such as PS-TTM-Cu (NCMe) [ PF6 ]]Iron-porphyrin coated Fe₃O₄Nanoparticles and rare earth cluster-based iron-porphyrin scaffolds. However, porphyrin derivatives are expensive due to their low selectivity and yield in the synthesis process. Therefore, the development of an iron-based heterogeneous catalyst which is convenient and economical to prepare is of great significance.

On the other hand, the porous carbon material has advantages of large specific surface area, controllable pore size, stable chemical and mechanical properties, diverse structure, good conductivity, etc., and is considered to be a good organic synthesis catalyst. The ethyl cellulose is a cellulose derivative, has the advantages of low cost, reproducibility and good solubility, and can be selected as a carbon source to prepare a carbon material. In addition, the existence of nitrogen not only can play a role in dispersing iron atoms, but also can improve the catalytic activity of iron.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to provide an iron-doped carbon material derived from ethyl cellulose, and the material as a catalyst has better activity, selectivity and stability compared with other existing catalysts for catalyzing N-H carbene insertion reaction. Another object of the present invention is to provide a method for preparing the ethylcellulose-derived iron-doped carbon material. It is also an object of the present invention to demonstrate the use of ethylcellulose-derived iron-doped carbon materials for catalyzing N-H carbene insertion reactions.

The technical scheme is as follows: the iron-doped carbon material derived from the ethyl cellulose comprises carbonized ethyl cellulose serving as a carbon material, nitrogen element, zinc element and iron existing in a particle form; the iron particles are surrounded by a porous carbon material, nitrogen element is doped into the carbon material, and the whole surface has spherical aggregate particles.

The iron-doped carbon material derived from ethyl cellulose has iron particles mainly made of Fe₂O₃FeO, and Fe.

The iron-doped carbon material derived from the ethyl cellulose has a graphite carbon structure.

The preparation method of the iron-doped carbon material derived from the ethyl cellulose comprises the following steps:

(1) heating ethyl cellulose to dissolve in anhydrous ethanol to obtain first solution, and dissolving Fe (NO)₃)₃·9H₂Dissolving a mixture of O and 2, 2' -bipyridyl in absolute ethyl alcohol to prepare a second solution, mixing the first solution and the second solution, and reacting to obtain a mixed solution;

(2) adding a nitrogen source and zinc source powder into the mixed solution obtained in the step (1), evaporating the solvent to obtain a solid, and drying;

(3) and (3) calcining the solid obtained in the step (2) in an inert gas atmosphere to obtain the iron-doped carbon material derived from the ethyl cellulose.

The preparation method of the iron-doped carbon material derived from the ethyl cellulose comprises the following steps of (1) heating at the temperature of 70-90 ℃, preferably 80 ℃; fe (NO)₃)₃·9H₂The feeding molar ratio of the O and the 2, 2' -bipyridyl is 1: 1-1: 2, and the preferable ratio is 1: 1.

According to the preparation method of the iron-doped carbon material derived from the ethyl cellulose, the nitrogen source in the step (2) is melamine; the zinc source is zinc nitrate hexahydrate; the drying temperature is 55-65 ℃.

In the preparation method of the iron-doped carbon material derived from the ethyl cellulose, the inert gas in the step (3) is nitrogen or argon; the calcination is carried out at 800-1000 ℃, preferably 900 ℃; in the calcining process, the heating rate is 3-8 ℃/min, preferably 5 ℃/min, and the calcining time is 2-3 h.

The application of the iron-doped carbon material derived from the ethyl cellulose in catalyzing N-H carbene insertion reaction.

The application of the iron-doped carbon material derived from the ethyl cellulose in preparing the unnatural amino acid derivative.

The application comprises the following steps: adding amine, an iron-doped carbon material derived from ethyl cellulose, ethyl diazoacetate and a solvent into a reaction container, sealing the reaction container under the condition of normal pressure and nitrogen, reacting at room temperature, after the reaction is finished, centrifugally separating the iron-doped carbon material derived from ethyl cellulose as a catalyst, removing an organic phase by rotary evaporation to obtain a crude product, and finally separating and purifying by column chromatography to obtain the target product.

In the invention, the iron-doped carbon material catalyst derived from the ethyl cellulose is marked as Fe @ CN-Zn, wherein Fe represents an iron element, NC represents a nitrogen-doped carbon material, and Zn represents a zinc element.

According to some preferred aspects of the invention, in step (1), the second solution is added to the first solution under stirring, the mixture is stirred for a while, and after the reaction is finished, the melamine powder and Zn (NO) are added₃)₂·6H₂O powder was added to the intermediate reaction mixture obtained in the above step (1), respectively. A solid was obtained by evaporation of the solution and dried at 55-65 ℃ for 12 h.

According to some preferred aspects of the invention, in step (2), the reaction is carried out at a temperature of 80 ℃.

According to some preferred aspects of the invention, in step (1), the second solution is first sonicated for 5 minutes.

According to some preferred aspects of the present invention, in the step (1), the first solution and the second solution are mixed to add the second solution to the first solution, and then stirred for 30 minutes.

According to some specific aspects of the invention, the calcining is performed in a tube furnace.

According to some preferred and specific aspects of the invention, in said use, the solvent is dichloromethane.

According to some preferred and specific aspects of the present invention, in said application, the feeding molar ratio of said amine to said ethyl diazoacetate is 2: 1.

According to some preferred and specific aspects of the present invention, in the application, the amount of the amine is 1mmol, based on the amine, and the Fe/N co-doped carbon material catalyst is 10 mg.

Has the advantages that: compared with the prior art, the invention has the following remarkable advantages: (1) compared with other existing catalysts for catalyzing N-H carbene insertion reaction, the catalyst has the advantages of better activity, more excellent selectivity and stability, high catalytic efficiency, good reusability, mild reaction conditions and good substrate tolerance. (2) The method for preparing the iron-doped carbon material catalyst derived from the ethyl cellulose has the advantages of simple process, cheap and easily-obtained raw materials, mild and environment-friendly conditions and easy large-scale production. (3) The preparation method is novel, simple and expandable.

Drawings

FIG. 1 is an SEM image of an ethylcellulose-derived iron-doped carbon material prepared in example 1;

FIG. 2 is a TEM image of an ethylcellulose-derived iron-doped carbon material prepared in example 1;

FIG. 3 is an XPS plot of an ethylcellulose-derived iron-doped carbon material prepared in example 1.

Detailed Description

In the following, all starting materials are either commercially available or prepared by conventional methods in the art, unless otherwise specified.

EXAMPLE 1 preparation of the catalyst Fe @ CN-Zn

The present example provides a method for preparing an ethylcellulose-derived iron-doped carbon material catalyst, comprising the steps of:

(1) dissolving 2.8g of ethyl cellulose in 50mL of absolute ethyl alcohol to prepare a first solution, and stirring for 1h at 80 ℃; 1mmol Fe (NO)₃)₃·9H₂Dissolving a mixture of O and 1mmol of 2, 2' -bipyridyl in 30mL of absolute ethanol by ultrasonic waves for 5 minutes to obtain a second solution; the second solution is then poured into the stirring first solution, the suspension is stirred for a further 30 minutes, mixed and finally 2.8g of melamine powder and 1.4g of Zn (NO)₃)₂·6H₂And adding O powder into the mixed solution. Stirring at 80 deg.C for 20h, after reaction, evaporating the obtained solid, and drying at 60 deg.C for 12 h;

(2) and (2) calcining the solid obtained in the step (1) at 900 ℃ for 2h in a tubular furnace in a nitrogen atmosphere (the heating rate is 5 ℃/min), and obtaining the final iron-doped carbon material derived from the ethyl cellulose, wherein the mark is Fe @ CN-Zn (Fe represents an iron atom, CN represents a nitrogen-doped carbon material, and Zn represents a zinc element). The obtained ethylcellulose-derived iron-doped carbon material was subjected to the following tests, and SEM images, TEM images, and XRD images thereof are respectively shown in fig. 1, fig. 2, and fig. 3, and the SEM images and TEM images illustrate that the ethylcellulose-derived iron-doped carbon material surface forms spherical aggregated particles, iron exists mainly in the form of particles, and the iron particles are surrounded by the carbon material, and the structure of the graphitic carbon-coated iron particles can inhibit the loss of iron during the reaction. XRD pattern indicates that iron is mainly Fe₂O₃FeO and Fe.

Comparative example 1

Basically, the method is the same as the method of the embodiment 1, and the method only differs from the method in that: the step (1) is different, and the step (1) is concretely as follows: (1) dissolving 2.8g of ethyl cellulose in 50mL of absolute ethyl alcohol to prepare a first solution, and stirring for 1h at 80 ℃; 1mmol of FeCl₃·6H₂Dissolving O in 30mL of absolute ethanol by ultrasonic waves for 5 minutes to obtain a second solution; the second solution is then poured into the stirring first solution, the suspension is stirred for a further 30 minutes, mixed and finally 2.8g of melamine powder and 1.4g of Zn (OAc)₂·2H₂And adding O powder into the mixed solution. Stirring at 80 deg.C for 20h, and evaporating the solutionObtaining a solid, and drying at 60 ℃ for 12 h;

comparative example 2

Basically, the method is the same as the method of the embodiment 1, and the method only differs from the method in that: the step (1) is different, and the step (1) is concretely as follows: (1) dissolving 2.8g of ethyl cellulose in 50mL of absolute ethyl alcohol to prepare a first solution, and stirring for 1h at 80 ℃; 1mmol of FeCl₃·6H₂Dissolving a mixture of O and 1mmol of 2, 2' -bipyridyl in 30mL of absolute ethanol by ultrasonic waves for 5 minutes to obtain a second solution; the second solution is then poured into the stirring first solution, the resulting suspension is stirred for a further 30 minutes, mixed and finally 1.4g of Zn (OAc)₂·2H₂And adding O powder into the mixed solution. Stirring at 80 deg.C for 20h, after reaction, evaporating the obtained solid, and drying at 60 deg.C for 12 h;

comparative example 3

Basically, the method is the same as the method of the embodiment 1, and the method only differs from the method in that: the step (1) is different, and the step (1) is concretely as follows: (1) dissolving 2.8g of ethyl cellulose in 50mL of absolute ethyl alcohol to prepare a first solution, and stirring for 1h at 80 ℃; 1mmol of Fe (NO)₃)₃·9H₂Dissolving a mixture of O and 1mmol of 2, 2' -bipyridyl in 30mL of absolute ethanol by ultrasonic waves for 5 minutes to obtain a second solution; the second solution was then poured into the stirring first solution, the suspension was stirred for a further 30 minutes, mixed and finally 2.8g of melamine powder were added to the mixture. Stirring at 80 deg.C for 20h, after reaction, evaporating the obtained solid, and drying at 60 deg.C for 12 h;

example 2N-H carbene insertion reaction

1mmol of amine of different structures as shown in Table 1, 10mg of Fe @ CN-Zn prepared in example 1, 0.5mmol of ethyl diazoacetate, 2mL of dichloromethane were added in this order to a reaction vessel, N₂The reaction was stirred at room temperature for 12h, and after completion of the reaction, ethyl acetate (4.0mL) was added to the mixture. The organic phase was removed by rotary evaporation to give the crude product. Finally, the pure product was obtained by simple silica gel column chromatography. The catalyst Fe @ CN-Zn can be recovered by simple centrifugation, washed with ethanol and dried in vacuo, and then directly reused in another reaction cycleAnd (4) a ring. The specific reaction yield of the catalyst Fe @ CN-Zn is shown in Table 1.

Application comparative example 1

Basically, the method is the same as the method of the embodiment 2, and the method only differs from the method in that: the "Fe @ CN-Zn prepared in example 1" was replaced with the catalyst prepared in comparative example 1.

Comparative application example 2

Basically, the method is the same as the method of the embodiment 2, and the method only differs from the method in that: "Fe @ CN-Zn prepared in example 1" was replaced with the catalyst prepared in comparative example 2.

TABLE 1

Therefore, the iron-doped carbon material derived from the ethyl cellulose can catalyze the N-H carbene insertion reaction well, and the reaction yield is improved. The N-H carbene complex has good application prospect in preparing non-natural amino acid derivatives as a catalyst of N-H carbene insertion reaction.