Application of cerium-based catalyst containing FLPs in hydrogenation of alpha, beta-unsaturated aldehyde

Abstract

The invention discloses a preparation method and application of a Ni / CeO2 / C catalyst with hindered Lewis acid-base pairs (FLPs), the mass fraction of Ce is 5%-13.5% on the basis that the mass of the catalyst is 100%, and the preparation method comprises the following steps: 1) respectively preparing a solution A containing cerium nitrate and nickel nitrate and a solution B containing terephthalic acid; (2) mixing and stirring the solution A and the solution B, and then transferring the solution A and the solution B into a high-pressure reaction kettle with a polytetrafluoroethylene lining for heating reaction; and 3) calcining the obtained solid at a high temperature in an N2 atmosphere, and finally performing high-temperature reduction treatment in a hydrogen / argon mixed atmosphere. The catalyst is low in preparation cost and mild in preparation condition. The Ni / CeO2 / C catalyst with FLPs provided by the invention has better performance on hydrogenation catalysis of alpha, beta-unsaturated aldehyde, and realizes conversion of unsaturated aldehyde into an intermediate product with higher value.

Description

Technical Field

[0001] This invention belongs to the field of thermocatalytic materials and biomass processing and utilization technology, and specifically relates to a cerium-based catalyst for the thermocatalytic hydrogenation of Δ,β-unsaturated aldehydes, its preparation method and application. Background Technology

[0002] α,β-Unsaturated aldehydes are an important class of organic molecules in the pharmaceutical and fine chemical industries. Among various α,β-unsaturated aldehydes, cinnamaldehyde (CAL) is an important and representative model reactant, and its selective hydrogenation product is widely used in the production of fragrances, food flavorings, and synthetic pharmaceutical intermediates. CAL itself contains two types of unsaturated chemical bonds: C=C and C=O. Hydrogenation of the C=C bond of CAL yields phenylpropanal (HCAL), and hydrogenation of the C=O bond of CAL yields cinnamyl alcohol (COL). Cinnamyl alcohol can be used in the production of fragrances and is also a good solvent, representing a high-value intermediate. Further hydrogenation of both HCAL and COL yields phenylpropanol (HCOL). While conventional noble metal catalysts can achieve the conversion of unsaturated aldehydes into valuable intermediates, they are costly and may pose environmental pollution risks. Furthermore, some noble metal catalysts require H2 as a hydrogen source, which significantly increases the cost of large-scale production. Summary of the Invention

[0003] Technical Problem Solved: To address the aforementioned defects and shortcomings, this invention designs a Ni / CeO2 / C catalyst with hindered Lewis acid-base pairs (FLPs). This catalyst can activate hydrogen molecules through FLPs, thereby realizing the hydrogenation process on a non-noble metal catalyst. Simultaneously, during the reaction, the hydrogen source mainly comes from the solvent, reducing the use of hydrogen gas.

[0004] Technical solution: A method for preparing a Ni / CeO2 / C catalyst containing FLPs, comprising a Ni / CeO2 / C catalyst containing FLPs composed of cerium nitrate hexahydrate, nickel nitrate hexahydrate and terephthalic acid: (1) First, dissolve Ce(NO3)3·6H2O and Ni(NO3)2·6H2O in a certain amount of DMF to obtain solution A; (2) Add a certain proportion of organic ligand (terephthalic acid) to a certain amount of DMF to obtain solution B; (3) Then, slowly pour solution A into solution B and magnetically stir for 30-90 minutes; (4) Transfer the obtained solution to a high-pressure reactor with a polytetrafluoroethylene liner; (5) After cooling to room temperature, centrifuge the obtained green precipitate and wash it several times with deionized water and ethanol. Dry the obtained solid product; (6) Calcine it at 350-500℃ under different reaction atmospheres (N2, H2 or air) for 1-3 hours, with a heating rate of 3-5℃ / min.

[0005] Preferably, in step (1), 1.0 g of Ce(NO3)3·6H2O and 0.7 g of Ni(NO3)2·6H2O are added, and 30 mL of DMF solution is taken.

[0006] Preferably, in step (2) above, the amount of DMF is 30 mL and the amount of terephthalic acid is 1.5 g;

[0007] Preferably, the stirring time in step (3) above is 60 minutes;

[0008] Preferably, the temperature in step (4) above is 120°C and the reaction time is 36 hours;

[0009] Preferably, the drying temperature in step (5) above is 70°C and the drying time is 12 hours;

[0010] Preferably, in step (6) above, the temperature is 500℃ and the time is 2h;

[0011] The cerium-based catalyst prepared by the above method.

[0012] The aforementioned Ni / CeO2 / C catalyst containing FLPs is characterized by being composed of cerium nitrate hexahydrate, nickel nitrate hexahydrate, and terephthalic acid, forming a Ni / CeO2 / C catalyst with FLPs.

[0013] The above-mentioned Ni / CeO2 / C catalyst containing FLPs is used in the catalysis of cinnamaldehyde.

[0014] The application of the above-mentioned Ni / CeO2 / C catalyst containing FLPs in cinnamaldehyde is characterized by the presence of 0.1 mmol of cinnamaldehyde in 5 ml of solvent and a reaction temperature of 70 °C.

[0015] Beneficial effects: (1) The catalyst is composed entirely of non-precious metals, resulting in extremely low cost; (2) The catalyst is prepared in one step and possesses extremely high catalytic activity and catalytic stability; (3) The catalyst preparation cost is low, the preparation conditions are mild, the operation is convenient, and it is easy to scale up production in industry; (4) The Ni / CeO2 / C containing FLPs provided by this invention belongs to the field of thermocatalytic materials and biomass processing and utilization technology, and particularly relates to a cerium-based catalyst for thermocatalytic hydrogenation of cinnamaldehyde, its preparation method, and its application. Attached Figure Description

[0016] Figure 1 Schematic diagram of the synthesized catalyst Detailed Implementation

[0017] To better illustrate the present invention and facilitate understanding of its technical solutions, typical but non-limiting embodiments of the present invention are as follows:

[0018] Example 1

[0019] A method for preparing a Ni / CeO2 / C catalyst containing FLPs, comprising a Ni / CeO2 / C catalyst composed of cerium nitrate hexahydrate, nickel nitrate hexahydrate and terephthalic acid: (1) First, 0.5g of Ce(NO3)3·6H2O and 0.7g of Ni(NO3)2·6H2O are dissolved in 30ml of DMF to obtain solution A; (2) 1.5g of organic ligand (terephthalic acid) is added to 30ml of DMF to obtain solution B; (3) Subsequently, solution A is slowly poured into solution B and magnetically stirred for 60 minutes; (4) The obtained solution is transferred to a high-pressure reactor with a polytetrafluoroethylene liner; (5) After cooling to room temperature, the obtained green precipitate is centrifuged and washed several times with deionized water and ethanol. The obtained solid product is dried; (6) calcined at 500℃ in N2 atmosphere for 2h and then cooled to room temperature. Finally, it is reduced at 500℃ in H2 atmosphere to obtain the final product.

[0020] Comparison Column 1

[0021] A method for preparing a cerium-free catalyst: (1) First, dissolve 0.7g of Ni(NO3)2·6H2O in 30ml of DMF to obtain solution A; (2) Add 1.5g of organic ligand (terephthalic acid) to 30ml of DMF to obtain solution B; (3) Then, slowly pour solution A into solution B and magnetically stir for 60 minutes; (4) Transfer the obtained solution to a high-pressure reactor with a polytetrafluoroethylene liner; (5) After cooling to room temperature, centrifuge the obtained green precipitate and wash it several times with deionized water and ethanol. Dry the obtained solid product; (6) calcine it at 500℃ in N2 atmosphere for 2h and then cool it to room temperature. Finally, reduce it at 500℃ in H2 atmosphere to obtain the final product.

[0022] Example 2

[0023] A method for preparing a Ni / CeO2 / C catalyst containing FLPs, comprising a Ni / CeO2 / C catalyst composed of cerium nitrate hexahydrate, nickel nitrate hexahydrate and terephthalic acid: (1) First, 0.8 g of Ce(NO3)3·6H2O and 0.7 g of Ni(NO3)2·6H2O are dissolved in 30 ml of DMF to obtain solution A; (2) 1.5 g of organic ligand (terephthalic acid) is added to 30 ml of DMF to obtain solution B; (3) Subsequently, solution A is slowly poured into solution B and magnetically stirred for 60 minutes; (4) The obtained solution is transferred to a high-pressure reactor with a polytetrafluoroethylene liner; (5) After cooling to room temperature, the obtained green precipitate is centrifuged and washed several times with deionized water and ethanol. The obtained solid product is dried; (6) calcined at 500 °C in N2 atmosphere for 2 h and then cooled to room temperature. Finally, it is reduced at 500 °C in H2 atmosphere to obtain the final product.

[0024] Example 3

[0025] A method for preparing a Ni / CeO2 / C catalyst containing FLPs, comprising a Ni / CeO2 / C catalyst composed of cerium nitrate hexahydrate, nickel nitrate hexahydrate and terephthalic acid: (1) First, 1.0 g of Ce(NO3)3·6H2O and 0.7 Ni(NO3)2·6H2O are dissolved in 30 ml of DMF to obtain solution A; (2) 1.5 g of organic ligand (terephthalic acid) is added to 30 ml of DMF to obtain solution B; (3) Subsequently, solution A is slowly poured into solution B and magnetically stirred for 60 minutes; (4) The obtained solution is transferred to a high-pressure reactor with a polytetrafluoroethylene liner; (5) After cooling to room temperature, the obtained green precipitate is centrifuged and washed several times with deionized water and ethanol. The obtained solid product is dried; (6) calcined at 500 °C in N2 atmosphere for 2 h and then cooled to room temperature. Finally, it is reduced at 500 °C in H2 atmosphere to obtain the final product.

[0026] Example 4

[0027] A method for preparing a Ni / CeO2 / C catalyst containing FLPs, comprising a Ni / CeO2 / C catalyst consisting of cerium nitrate hexahydrate, nickel nitrate hexahydrate and terephthalic acid: (1) First, 1.2g of Ce(NO3)3·6H2O and 0.7g of Ni(NO3)2·6H2O are dissolved in 30ml of DMF to obtain solution A; (2) 1.5g of organic ligand (terephthalic acid) is added to 30ml of DMF to obtain solution B; (3) Subsequently, solution A is slowly poured into solution B and magnetically stirred for 60 minutes; (4) The obtained solution is transferred to a high-pressure reactor with a polytetrafluoroethylene liner; (5) After cooling to room temperature, the obtained green precipitate is centrifuged and washed several times with deionized water and ethanol. The obtained solid product is dried; (6) calcined at 500℃ in N2 atmosphere for 2h and then cooled to room temperature. Finally, it is reduced at 500℃ in H2 atmosphere to obtain the final product.

[0028] Example 5

[0029] A method for preparing a Ni / CeO2 / C catalyst containing FLPs, comprising a Ni / CeO2 / C catalyst composed of cerium nitrate hexahydrate, nickel nitrate hexahydrate and terephthalic acid: (1) First, 1.5g of Ce(NO3)3·6H2O and 0.7g of Ni(NO3)2·6H2O are dissolved in 30ml of DMF to obtain solution A; (2) 1.5g of organic ligand (terephthalic acid) is added to 30ml of DMF to obtain solution B; (3) Subsequently, solution A is slowly poured into solution B and magnetically stirred for 60 minutes; (4) The obtained solution is transferred to a high-pressure reactor with a polytetrafluoroethylene liner; (5) After cooling to room temperature, the obtained green precipitate is centrifuged and washed several times with deionized water and ethanol. The obtained solid product is dried; (6) calcined at 500℃ in N2 atmosphere for 2h and then cooled to room temperature. Finally, it is reduced at 500℃ in H2 atmosphere to obtain the final product.

[0030] Example 6

[0031] Cinnamaldehyde was selected as the substrate for this reaction. Specific steps: 150 mg of the catalyst prepared according to the methods described in Examples 1-5 and Comparative Example 1 was dispersed in 5 mL of isopropanol solution containing 0.1 mmol of cinnamaldehyde. Nitrogen gas was purged through the entire reactor to maintain a nitrogen-filled state, and the reactor pressure was maintained at 0.1 MPa. The reaction was carried out in an oil bath at 70°C for 2 hours. The resulting mixed solution was centrifuged and filtered to obtain the supernatant, which was then analyzed by gas chromatography (GC7900, FID).

[0032]

[0033] Table 1. Activity evaluation results of Ni / CeO2 / C catalysts containing FLPs

[0034]

[0035] As shown in Table 1, this invention, by constructing hindered Lewis acid-base pairs (FLPs), can effectively convert α,β-unsaturated aldehydes into other intermediate products with higher value, thus realizing the hydrogenation process on a non-precious metal catalyst. It can also be seen that both excessively low and excessively high cerium content in the catalyst will affect its performance.

[0036] The foregoing description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a cerium-based catalyst, characterized in that, The mass fraction of Ce is 5% to 13.5% based on 100% of the catalyst mass. Ni / CeO2 / C catalyst with hindered Lewis acid-base pairs (FLPs) composed of cerium nitrate hexahydrate, nickel nitrate hexahydrate and terephthalic acid: (1) First, dissolve Ce(NO3)3·6H2O and Ni(NO3)2·6H2O in a certain amount of DMF to obtain solution A; (2) Add a certain proportion of organic ligand (terephthalic acid) to a certain amount of DMF to obtain solution B; (3) Then, slowly pour solution A into solution B and magnetically stir for 30-90 minutes; (4) Transfer the obtained solution to a high-pressure reactor with a polytetrafluoroethylene liner; (5) After cooling to room temperature, centrifuge the obtained green precipitate and wash it several times with deionized water and ethanol. Dry the obtained solid product; (6) Calcine it at 350℃-500℃ using different gases (N2, H2 or air) for 1-3 hours with a heating rate of 3-5℃ / min.

2. The method for preparing the Ni / CeO2 / C catalyst containing FLPs according to claim 1, characterized in that, In step (1), 0.5-1.5 g of Ce(NO3)3·6H2O and 0.3-1.0 g of Ni(NO3)2·6H2O are added, and 15-30 mL of DMF solution is taken.

3. The method for preparing the Ni / CeO2 / C catalyst containing FLPs according to claim 1, characterized in that, In step (2), the amount of DMF is 15-30 mL and the amount of terephthalic acid is 0.7-1.5 g.

4. The method for preparing the manganese carbonate catalyst according to claim 1, characterized in that, The drying temperature in step (4) is 60-180℃ and the time is 20-40h.

5. The cerium-based catalyst prepared by any one of the preparation methods described in claims 1-5.

6. The Ni / CeO2 / C catalyst containing FLPs according to claim 6, characterized in that... It is composed of cerium nitrate hexahydrate, nickel nitrate hexahydrate and terephthalic acid, forming a cerium-based catalyst.

7. The application of the Ni / CeO2 / C catalyst containing FLPs as described in claim 7 in the catalysis of α,β-unsaturated aldehydes (taking cinnamaldehyde as an example).

8. The application of the Ni / CeO2 / C catalyst containing FLPs as described in claim 8 in the catalysis of cinnamaldehyde, characterized in that, The cinnamaldehyde content is 0.1 mmol-1.0 mmol, and the reaction temperature is 50-100℃.

Images