CN116099537A - Ni-NiO multiphase magnetic catalyst, preparation method and application thereof - Google Patents

Abstract

The invention relates to a Ni-NiO multiphase magnetic catalyst and a preparation method and application thereof, wherein Ni salt and a carbon source are taken as initial raw materials, the initial raw materials are mixed and dissolved in a specific solvent, ultrasonic stirring is carried out at a certain temperature, the mixture is aged and dried after stirring for a certain time, and is reduced for 1-5 hours at 200-900 ℃ under the protection of hydrogen and inert mixed gas to obtain solid powder, the solid powder is oxidized for 1-5 hours at 100-300 ℃ in oxygen and inert gas, and then the Ni-NiO multiphase magnetic catalyst is obtained after freeze drying, grinding and sieving. The Ni-NiO multiphase magnetic catalyst adopted by the invention has the advantages of low preparation cost, simple preparation process, easy recycling of magnetism and the like. The conversion rate of the furfuryl amine methylation reaction catalyzed by the catalyst is up to 99%, and the selectivity of the corresponding methylation reaction product N, N-dimethyl-2-furanmethylamine is up to 98%.

Description

A kind of Ni-NiO heterogeneous magnetic catalyst and its preparation method and application

technical field

The invention relates to the technical field of catalysts, in particular to a Ni-NiO heterogeneous magnetic catalyst, a preparation method and an application thereof.

Background technique

N-functionalized amines, especially N-methylamines and amides, are very important pharmaceutical intermediates and are widely used in the synthesis of dyes, perfumes, pesticides and pharmaceutical products. N-methylamines are usually prepared by the N-methylation method of amines, which is an effective method to adjust biological and pharmaceutical properties by adding magical methyl groups.

Traditional N-methylation methods usually employ amines and activated methyl compounds, such as toxic methyl iodide, dimethyl sulfoxide, or dimethyl carbonate. These synthetic processes are complex in operation, narrow in scope of application of amines, many by-products, and generate a large amount of waste. In recent years, the green and sustainable amine N-methylation reaction using transition metal catalysis mainly adopts more environmentally friendly and safer methylation reagents, such as MeOH, CO ₂ , HCOOH, formaldehyde, etc.

So far, various homogeneous and heterogeneous metal catalysts have been reported. For homogeneous catalyst systems, Ru complex catalysts have been widely used and investigated for the direct N-methylation of amines using CO2 as a C1 source. In 2013, the Beller research group disclosed a homogeneous catalyst system, which applied the commercially available RuCl ₂ (dmso) ₄ and BuPAd ₂ ligands to the N-methylation reaction of amine compounds with various functional groups, especially It is an amine compound with unsaturated functional groups such as C=O, C=C, C≡N, and C≡C, _PhSiH3 is used as a hydrogen source, _{and CO2} is used as a methylating agent to obtain very good amine methylation conversion and excellent selectivity to N-methylated products.

Although the N-methylation reaction of amine compounds catalyzed by homogeneous catalysts has been developed, the recovery of the currently developed homogeneous catalysts is difficult, and the ligand synthesis is complicated and the production cost is high, so it is difficult to meet the current demand for N-methylated drugs and pesticides. , A large demand for fine chemicals. There is an urgent need to explore low-cost, high-performance, stable, and easily separable sustainable heterogeneous catalysts.

Contents of the invention

Aiming at the deficiencies of the prior art, the present invention provides a Ni-NiO heterogeneous magnetic catalyst, its preparation method and its application to realize the selective N-methylation reaction of furfurylamine under mild conditions to prepare N,N-dimethyl-2 - Target of furanylamine.

The technical scheme that the present invention adopts is as follows:

The present application provides a method for preparing a Ni-NiO heterogeneous magnetic catalyst on the one hand, comprising:

Step 1: Mix metal Ni salt and carbon source in a solvent according to a certain ratio, and ultrasonically stir at 20-100°C for 1-8h, then dry the stirred mixture and reduce it at 200-900°C under the protection of hydrogen and inert mixed gas 1～5h to get solid powder;

Step 2: Oxidize the solid powder in oxygen and inert gas at 100-300°C for 1-5 hours, then freeze-dry, grind and sieve to obtain a Ni-NiO heterogeneous magnetic catalyst.

The anion of the metal Ni salt is any one of sulfate ion, nitrate ion, acetate ion, halide ion, phosphate ion;

The carbon source is any one of organic acids such as tartaric acid, malic acid, glucose, benzene citric acid, formic acid, salicylic acid, oxalic acid;

The molar ratio of the metal Ni salt to the carbon source is 1:(1～10);

The solvent is one or a mixture of ethyl acetate, petroleum ether, deionized water, methanol, ethanol, tetrahydrofuran, n-butanol, and cyclohexane.

In step 1, the reduction method of the mixture under the condition of hydrogen and inert gas is as follows: at room temperature, the temperature is raised to 200-900°C at a rate of 1-5°C/min, and the highest temperature is maintained for 1-5h, and naturally cooled to room temperature in _N2 flow .

In step 2, the method of heating and oxidizing the solid powder in oxygen and inert gas is: at room temperature at a rate of 1-5 °C/min _to 100-300 °C, maintaining the highest temperature for 1-5 hours, and naturally cooling to room temperature.

In the second step, the volume ratio of oxygen in the mixed gas of oxygen and inert gas is 0.1-10 vol%.

The second aspect of the present application provides a Ni-NiO heterogeneous magnetic catalyst obtained according to the method for preparing the Ni-NiO heterogeneous magnetic catalyst, which is composed of Ni and NiO.

The third aspect of the present application provides an application of the Ni-NiO heterogeneous magnetic catalyst in the furfurylamine methylation process, including:

Put the catalyst in a high-pressure reactor, add formaldehyde, furfurylamine and solvent, seal it, pass in a certain pressure of hydrogen, set the reaction time, stirring speed, and reaction temperature, carry out the furfurylamine methylation reaction, and cool down after the set time is over to room temperature, the methylated product was obtained.

The solvent is toluene, methanol, ethanol, deionized water, acetonitrile, ethyl acetate, 1,4 dioxane, cyclohexane, 2-butanol, methylene chloride, isopropanol, N,N-di One or more of methylformamide, chloroform, tetrahydrofuran.

The pressure of hydrogen is 0.1-5.0Mpa, the reaction temperature is 30-150°C, and the reaction time is 0.5-6h.

The catalyst after the catalyzed reaction is separated magnetically, fully washed in water until neutral, freeze-dried, and recycled.

The beneficial effects of the present invention are as follows:

The present invention rationally designs and prepares a Ni-NiO heterogeneous magnetic catalyst through an ultrasonic in-situ synthesis process, and at the same time constructs a highly efficient and mild furfuryl amine methylation reaction catalytic system, which can improve the conversion rate of furfuryl amine and the corresponding target product N, The selectivity of N-dimethyl-2-furylmethylamine is high. Under the conditions of 2.0MPa, 80°C and methanol as the solvent, the catalyst can realize the efficient and selective methylation reaction of furfurylamine to generate N,N-dimethyl-2-furylamine.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention.

Description of drawings

Fig. 1 is a hydrogen temperature programmed reduction (H ₂ -TPR) diagram of the catalyst in Example 1 of the present invention.

Detailed ways

The specific embodiments of the present invention will be described below in conjunction with the accompanying drawings.

Example 1

The preparation method of a Ni-NiO heterogeneous magnetic catalyst Ni-NiO@-H-O-S of the present embodiment, wherein H represents the reduction temperature, O represents the oxidation temperature, and S represents the solvent, comprising the following steps:

S1. Mix 0.03mmol of nickel nitrate, 0.03mmol of citric acid and 20mL of deionized water, and then ultrasonically stir at 70°C for 3h. The stirred mixture is dried at 100°C for 24h, and then placed in a nitrogen and hydrogen atmosphere at 700°C. Reduction 3h obtains solid powder;

S2. Oxidize the solid powder obtained in S1 at 200°C in oxygen and inert gas for 1 h, then freeze-dry, grind, and sieve to obtain Ni-NiO heterogeneous magnetic catalyst Ni-NiO@-700-200-H ₂ O .

As shown in Fig. 1, it can be clearly observed that the catalyst has two _H2 reduction peaks, which further illustrates that the catalyst is composed of Ni and NiO.

Example 2-8

Four groups of Ni-NiO heterogeneous magnetic catalysts Ni-NiO@-600-200-H 2 O, Ni-NiO@-700-200-H ₂ O, Ni-NiO@-700-200-H ₂ O, Ni-NiO@-600-200-EtOH, Ni-NiO@-700-200-EtOH and purchased commercial catalysts, see Table 1 for details, each group of Ni-NiO heterogeneous magnetic catalysts Ni-NiO@-HOS and purchased The commercial catalyst of is applied in the reaction of furfurylamine methylation respectively, comprises the following steps:

Put 10mg of catalyst, 0.5mmol of furfurylamine, 3mmol of formaldehyde and 5mL of methanol solvent into the autoclave and seal it, pour in 2MPa hydrogen, set the reaction temperature at 80°C and keep it at 80°C for 4h, the stirring rate is 300rpm, set the reaction After the time ended, the reaction kettle was naturally cooled, and the mixture of the reaction liquid and the catalyst was poured out after the pressure was released. Using magnetic force to fix the Ni-NiO heterogeneous magnetic catalyst in the above reaction solution, filter other commercial catalysts with filter paper, and pour out the clear reaction solution to obtain the reacted catalyst.

The qualitative and quantitative analysis of the reaction products in the reaction liquid was carried out by NMR and GC-MS, and the conversion rate of furfurylamine and the selectivity of the corresponding products were obtained.

A total of 7 groups of catalysts in Examples 2-8 include commercial catalysts and prepared Ni-NiO heterogeneous magnetic catalysts. The conversion rate and the selectivity results of the corresponding products in the methylation reaction of furfuryl amine are shown in Table 1.

Table 1

Table 1 shows the furfurylamine methylation chemical formula shown in the head of the table, as can be seen from Examples 2-8, different reduction temperatures, and catalyst preparation solvents for Ni-NiO heterogeneous magnetic catalyst Ni-NiO@-HOS furfurylamine first The performance of the methylation reaction has a greater impact, and different commercial catalysts have a greater impact on the performance of the methylation reaction of furfurylamine. When the reduction temperature is 700°C and the solvent used for catalyst preparation is H ₂ O, under mild reaction conditions (2MPa H ₂ , 80°C, 4h), the conversion rate of furfurylamine reaches 99%, corresponding to the target product N,N - The selectivity of dimethyl-2-furylmethylamine reaches 99%.

Examples 9-14

In order to verify the effect of different solvents on the performance of Ni-NiO heterogeneous magnetic catalyst Ni-NiO@-HOS furfurylamine methylation reaction. Set up Examples 9-14, all using the preparation method of Example 1 to prepare Ni-NiO heterogeneous magnetic catalyst Ni-NiO@-700-200-H ₂ O, and apply it to the methylation reaction of furfurylamine, Specifically include the following steps:

Put 10mg of catalyst, 0.5mmol of furfurylamine, 3mmol of formaldehyde and 5mL of solvent into the autoclave and seal it, pour in 2MPa of H ₂ , set the reaction temperature to 80°C and keep it at 80°C for 4h, the stirring rate is 300rpm, set the reaction After the time ended, the reaction kettle was naturally cooled, and the mixture of the reaction liquid and the catalyst was poured out after the pressure was released. Using magnetic force to fix the Ni-NiO heterogeneous magnetic catalyst in the above reaction solution, pouring out the clear reaction solution to obtain the reacted catalyst.

The qualitative and quantitative analysis of the reaction products in the reaction liquid was carried out by NMR and GC-MS, and the conversion rate of furfurylamine and the selectivity of the corresponding products were obtained.

The solvents used in Examples 9-14 and the reaction products in the reaction solutions obtained in each example were qualitatively and quantitatively analyzed by NMR and GC-MS, and the results of the conversion rate of furfurylamine and the selectivity of the corresponding products are shown in Table 2.

Table 2

The header of Table 2 shows the chemical formula of the methylation reaction of furfurylamine. It can be known from Examples 9-14 that different solvents have a great influence on the performance of the catalyst for the methylation reaction of furfurylamine. In solvents such as methanol and ethanol, the catalyst activity is relatively high, and in methanol solvent, the catalyst activity and product selectivity reach the best results, the conversion rate of furfurylamine is 99%, and the product selectivity is 99%. In dichloromethane, ethyl acetate, cyclohexane, tetrahydrofuran and other solvents, although the catalytic activity of the catalyst for the methylation of furfurylamine is high, and the conversion rate of furfurylamine reaches 99%, the target product N,N-dimethyl- The selectivity of 2-furylmethylamine is low, and a large amount of by-products are generated.

Examples 15-19

In order to verify the effect of different molar ratios of formaldehyde and furfuryl amine on the performance of Ni-NiO heterogeneous magnetic catalyst Ni-NiO@-HOS furfuryl amine methylation reaction. Set up Examples 15-19, all using the preparation method of Example 1 to prepare Ni-NiO heterogeneous magnetic catalyst Ni-NiO@-700-200-H ₂ O, and apply it in the methylation reaction of furfurylamine, Specifically include the following steps:

Put 10mg of catalyst, 0.5mmol of furfurylamine, certain mmol of formaldehyde and 5mL of solvent into the autoclave and seal it, pour in 2MPa of H ₂ , set the reaction temperature at 80°C and keep it at 80°C for 4h, the stirring rate is 300rpm, set After the given reaction time is over, the reaction kettle is naturally cooled, and the mixture of the reaction liquid and the catalyst is poured out after the pressure is released. Using magnetic force to fix the Ni-NiO heterogeneous magnetic catalyst in the above reaction solution, pouring out the clear reaction solution to obtain the reacted catalyst.

The qualitative and quantitative analysis of the reaction products in the reaction liquid was carried out by NMR and GC-MS, and the conversion rate of furfurylamine and the selectivity of the corresponding products were obtained.

The solvents used in Examples 15-19 and the reaction products in the reaction solutions obtained in each example were qualitatively and quantitatively analyzed by NMR and GC-MS. The results of the conversion of furfurylamine and the selectivity of the corresponding products are shown in Table 3.

table 3

The header of Table 3 shows the chemical formula of the furfurylamine methylation reaction. From Examples 15-19, it can be known that different molar ratios of formaldehyde/furfurylamine have a great influence on the performance of the catalyst for the furfurylamine methylation reaction. When the molar ratio of formaldehyde/furfurylamine is 1/2, the conversion rate of furfurylamine reaches 99%, and the product selectivity of N,N-dimethyl-2-furylamine reaches 97%.

Those of ordinary skill in the art can understand that: the above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, It is still possible to modify the technical solutions described in the foregoing embodiments, or to perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. a preparation method of Ni-NiO heterogeneous magnetic catalyst, is characterized in that, comprises: Step 1: Mix metal Ni salt and carbon source in a solvent according to a certain ratio, and ultrasonically stir at 20-100°C for 1-8h, then dry the stirred mixture and reduce it at 200-900°C under the protection of hydrogen and inert mixed gas 1～5h to get solid powder; Step 2: Oxidize the solid powder in oxygen and inert gas at 100-300°C for 1-5 hours, then freeze-dry, grind and sieve to obtain a Ni-NiO heterogeneous magnetic catalyst. 2. the preparation method of a kind of Ni-NiO heterogeneous magnetic catalyst according to claim 1 is characterized in that, the anion of described metal Ni salt is sulfate ion, nitrate ion, acetate ion, halide ion, phosphoric acid Any of the root ions; The carbon source is any one of organic acids such as tartaric acid, malic acid, glucose, benzene citric acid, formic acid, salicylic acid, oxalic acid; The molar ratio of the metal Ni salt to the carbon source is 1:(1～10); The solvent is one or a mixture of ethyl acetate, petroleum ether, deionized water, methanol, ethanol, tetrahydrofuran, n-butanol, and cyclohexane. 3. the preparation method of a kind of Ni-NiO heterogeneous magnetic catalyst according to claim 1 is characterized in that, in step 1, the reduction method of the mixture under hydrogen and inert gas conditions is: at room temperature at a rate of 1 to 5 °C/min rises to 200-900 °C, maintains the highest temperature for 1-5 hours, and naturally cools to room temperature in _N2 flow. 4. the preparation method of a kind of Ni-NiO heterogeneous magnetic catalyst according to claim 1 is characterized in that, in step 2, the method for heating up and oxidizing solid powder in oxygen and inert gas is: at room temperature at a rate of 1～ Rise to 100-300°C at 5°C/min, maintain the highest temperature for 1-5h, and cool naturally to room temperature in _N2 flow. 5. the preparation method of a kind of Ni-NiO heterogeneous magnetic catalyst according to claim 1, is characterized in that, in described step 2, the volume ratio of oxygen in the mixed gas of described oxygen and inert gas is 0.1～ 10vol%. 6. A Ni-NiO heterogeneous magnetic catalyst obtained by the method for preparing the Ni-NiO heterogeneous magnetic catalyst according to any one of claims 1-5, wherein the catalyst is composed of Ni and NiO. 7. an application of Ni-NiO heterogeneous magnetic catalyst according to claim 6 in furfurylamine methylation process, is characterized in that, comprises: Put the catalyst in a high-pressure reactor, add formaldehyde, furfurylamine and solvent, seal it, pass in a certain pressure of hydrogen, set the reaction time, stirring speed, and reaction temperature, carry out the furfurylamine methylation reaction, and cool down after the set time is over to room temperature, the methylated product was obtained. 8. the application of Ni-NiO heterogeneous magnetic catalyst according to claim 7 in furfurylamine methylation process is characterized in that, described solvent is toluene, methyl alcohol, ethanol, deionized water, acetonitrile, ethyl acetate , 1,4-dioxane, cyclohexane, 2-butanol, dichloromethane, isopropanol, N,N-dimethylformamide, chloroform, tetrahydrofuran or one or more. 9. The application of the Ni-NiO heterogeneous magnetic catalyst in the furfurylamine methylation process according to claim 7, characterized in that the pressure of hydrogen is 0.1-5.0Mpa, the reaction temperature is 30-150°C, and the reaction time is 0.5 ~6h. 10. the application of Ni-NiO heterogeneous magnetic catalyst according to claim 7 in furfuryl amine methylation process is characterized in that, the catalyzer after the catalyzed reaction is separated through magnetic easy, fully washes to neutrality in water, After freeze-drying, it is recycled.

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