Preparation method of nitrogen-doped hierarchical-porous carbon-loaded nanometer Pd catalyst and product and application thereof

Abstract

Disclosed are a nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst and a preparation method thereof. The preparation method includes preparing nitrogen-doped hierarchical-porous carbon, mixing the nitrogen-doped hierarchical-porous carbon with water, adjusting a pH value of the mixed solution to be alkaline, mixing the mixed solution with a Pd metal precursor aqueous solution, and then adding a reducing agent to obtain the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst after reduction. The prepared nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst includes a nitrogen-doped porous carbon material carrier with hierarchical pores and Pd metal nanoparticles loaded in the hierarchical pores of the carrier. The Pd metal nanoparticles have a size of 2˜14 nm and a regular polyhedron shape. The nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst has excellent catalytic performance, especially has ultra-high conversion rate, selectivity and cycle stability in the selective hydrogenation reaction of unsaturated ketones, and is a key to open a new synthetic route of vitamin E.

Claims

1. A preparation method of a nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst, comprising: 1) Preparing nitrogen-doped hierarchical-porous carbon; 2) Mixing the nitrogen-doped hierarchical-porous carbon prepared in step 1) with water, and adjusting a pH value of the mixed solution to be alkaline; and 3) Mixing the mixed solution prepared in step 2) with a Pd metal precursor aqueous solution, and then adding a reducing agent to obtain the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst after reduction.

2. The preparation method of the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst according to claim 1, wherein in step 2): a mass-volume ratio of the nitrogen-doped hierarchical-porous carbon to water is 1:20-200 g/mL; and the pH value of the mixed solution is adjusted to 8-12.

3. A nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst formed according to the method of claim 2, comprising: a nitrogen-doped porous carbon material carrier with hierarchical pores, and Pd metal nanoparticles loaded in the hierarchical pores of the carrier, wherein: the Pd metal nanoparticles have a particle size of 2-14 nm, and are each of a regular polyhedron shape; and the mass fraction of the Pd metal nanoparticles is 0.1%-10%.

4. A method of performing a catalytic hydrogenation reaction, comprising: providing the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst according to claim 3; providing a substrate for the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst; and performing a catalytic hydrogenation reaction on the substrate with the nitrogen-doped hierarchical-porous carbon loaded nano-Pd catalyst.

5. The method according to claim 4, wherein: the substrate is an unsaturated ketone; and the unsaturated ketone is at least one selected from the group consisting of 6-methyl-5-heptene-2-one, 6-methyl-3,5-heptadiene-2-one, 6,10-dimethyl-5-ene-2-undecanone, 6,10-dimethyl-5,9-diene-2-undecanone, 6,10-dimethyl-3,5-diene-2-undecanone, 6,10,14-trimethyl-5-ene-2-pentadecanone, 6,10,14-trimethyl-5,9,13-triene-2-pentadecanone, 6,10,14-trimethyl-3,5-diene-2-pentadecanone, cis-3,7-dimethyl-2,6-diene-octanal, and trans-3,7-dimethyl-2,6-diene-octanal.

6. The preparation method of the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst according to claim 1, wherein in step 3): the Pd metal precursor is selected from soluble salts of Pd metal; the concentration of the Pd metal precursor aqueous solution is 1-50 mg/mL; and a mass ratio of the nitrogen-doped hierarchical-porous carbon to the Pd metal precursor is (3-600):1.

7. A nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst formed according to the method of claim 6, comprising: a nitrogen-doped porous carbon material carrier with hierarchical pores, and Pd metal nanoparticles loaded in the hierarchical pores of the carrier, wherein: the Pd metal nanoparticles have a particle size of 2-14 nm, and are each of a regular polyhedron shape; and the mass fraction of the Pd metal nanoparticles is 0.1%-10%.

8. A method of performing a catalytic hydrogenation reaction, comprising: providing the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst according to claim 7; providing a substrate for the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst; and performing a catalytic hydrogenation reaction on the substrate with the nitrogen-doped hierarchical-porous carbon loaded nano-Pd catalyst.

9. The method according to claim 8, wherein: the substrate is an unsaturated ketone; and the unsaturated ketone is at least one selected from the group consisting of 6-methyl-5-heptene-2-one, 6-methyl-3,5-heptadiene-2-one, 6,10-dimethyl-5-ene-2-undecanone, 6,10-dimethyl-5,9-diene-2-undecanone, 6,10-dimethyl-3,5-diene-2-undecanone, 6,10,14-trimethyl-5-ene-2-pentadecanone, 6,10,14-trimethyl-5,9,13-triene-2-pentadecanone, 6,10,14-trimethyl-3,5-diene-2-pentadecanone, cis-3,7-dimethyl-2,6-diene-octanal, and trans-3,7-dimethyl-2,6-diene-octanal.

10. The preparation method of the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst according to claim 1, wherein in step 3): the reducing agent is selected from at least one of hydrazine hydrate, formic acid, sodium borohydride, and sodium formate; and a mass ratio of the reducing agent to the Pd metal precursor is (1-20):1.

11. The preparation method of the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst according to claim 10, wherein the reducing agent is added in a form of a reducing agent aqueous solution, and a mass-volume ratio of the reducing agent to water is 1-20 mg/mL.

12. A nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst formed according to the method of claim 11, comprising: a nitrogen-doped porous carbon material carrier with hierarchical pores, and Pd metal nanoparticles loaded in the hierarchical pores of the carrier, wherein: the Pd metal nanoparticles have a particle size of 2-14 nm, and are each of a regular polyhedron shape; and the mass fraction of the Pd metal nanoparticles is 0.1%-10%.

13. A nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst formed according to the method of claim 10, comprising: a nitrogen-doped porous carbon material carrier with hierarchical pores, and Pd metal nanoparticles loaded in the hierarchical pores of the carrier, wherein: the Pd metal nanoparticles have a particle size of 2-14 nm, and are each of a regular polyhedron shape; and the mass fraction of the Pd metal nanoparticles is 0.1%-10%.

14. The preparation method of the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst according to claim 1, wherein in step 3): the reduction temperature is 0-80° C., and the reduction time is 1-360 min.

15. A nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst formed according to the method of claim 14, comprising: a nitrogen-doped porous carbon material carrier with hierarchical pores, and Pd metal nanoparticles loaded in the hierarchical pores of the carrier, wherein: the Pd metal nanoparticles have a particle size of 2-14 nm, and are each of a regular polyhedron shape; and the mass fraction of the Pd metal nanoparticles is 0.1%-10%.

16. The preparation method of the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst according to claim 1, wherein in step 3): the reduced product is filtered to obtain the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst; and the water content of the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst is 5-75 wt %.

17. A nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst formed according to the method of claim 16, comprising: a nitrogen-doped porous carbon material carrier with hierarchical pores, and Pd metal nanoparticles loaded in the hierarchical pores of the carrier, wherein: the Pd metal nanoparticles have a particle size of 2-14 nm, and are each of a regular polyhedron shape; and the mass fraction of the Pd metal nanoparticles is 0.1%-10%.

18. A nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst formed according to the method of claim 1, comprising: a nitrogen-doped porous carbon material carrier with hierarchical pores, and Pd metal nanoparticles loaded in the hierarchical pores of the carrier, wherein: the Pd metal nanoparticles have a particle size of 2-14 nm, and are each of a regular polyhedron shape; and the mass fraction of the Pd metal nanoparticles is 0.1%-10%.

19. A method of performing a catalytic hydrogenation reaction, comprising: providing of the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst according to claim 18; providing a substrate for the nitrogen-doped hierarchical-porous carbon loaded nano-Pd catalyst; and performing a catalytic hydrogenation reaction on the substrate with the nitrogen-doped hierarchical-porous carbon loaded nano-Pd catalyst.

20. The method according to claim 19, wherein: the substrate is an unsaturated ketone; and the unsaturated ketone is at least one selected from the group consisting at least one of 6-methyl-5-heptene-2-one, 6-methyl-3,5-heptadiene-2-one, 6,10-dimethyl-5-ene-2-undecanone, 6,10-dimethyl-5,9-diene-2-undecanone, 6,10-dimethyl-3,5-diene-2-undecanone, 6,10,14-trimethyl-5-ene-2-pentadecanone, 6,10,14-trimethyl-5,9,13-triene-2-pentadecanone, 6,10,14-trimethyl-3,5-diene-2-pentadecanone, cis-3,7-dimethyl-2,6-diene-octanal, and trans-3,7-dimethyl-2,6-diene-octanal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is an X-ray diffraction diagram of a nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst prepared in Example 1;

(2) FIG. 2 is a scanning electron micrograph of the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst prepared in Example 1;

(3) FIG. 3 is a transmission electron micrograph of the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst prepared in Example 1, in which a further enlarged image of the catalyst and the particle size distribution are provided in small pictures respectively;

(4) FIG. 4 is a chemical reaction formula of a selective hydrogenation reaction of monoketene on the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst in the present invention;

(5) FIG. 5 is a chemical reaction formula of a selective hydrogenation reaction of diketene and triketene on the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst in the present invention;

(6) FIG. 6 is a chemical reaction formula of a selective hydrogenation reaction of diketene and triketene on the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst in the present invention;

(7) FIG. 7 shows cyclic application performance comparison curves of the preparation of 6-methyl-2-heptanone (II) by the selective hydrogenation of 6-methyl-3,5-heptadiene-2-one (VII) in the catalysts prepared in Example 1, Comparative Example 1 and Comparative Example 2;

(8) FIG. 8 shows a cyclic application performance comparison curve of the preparation of 6,10-dimethyl-2-undecanone (IV) by the selective hydrogenation of 6,10-dimethyl-3,5-diene-2-undecanone (IX) in the catalyst prepared in Example 1;

(9) FIG. 9 shows a cyclic application performance comparison curve of the preparation of 6,10,14-trimethyl-2-pentadecanone (VI) by the selective hydrogenation of 6,10,14-trimethyl-3,5-diene-2-pentadecanone (X) in the catalyst prepared in Example 1.

DETAILED DESCRIPTION

(10) The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

Example 1

(11) 4 g of cellulose, 12 g of sodium bicarbonate and 12 g of ammonium oxalate are weighed, mechanically mixed and transferred to a 30 mL crucible, and then calcined in a nitrogen furnace. The calcination step is as follows: heating up to 800° C. at 10° C./min; calcining at 800° C. for 1 h; and then naturally cooling to room temperature. The calcined product is ground and mixed with deionized water, and then filtered after standing for 24 hours. The precipitate is then washed to neutrality, and dried to obtain a nitrogen-doped hierarchical-porous carbon material for later use.

(12) 1 g of nitrogen-doped hierarchical-porous carbon material is weighed, added to 60 mL of deionized water, stirred at room temperature, and slowly added with 100 mg/mL NaOH aqueous solution dropwise to adjust the pH value of the mixed solution to 10. 1 mL of 10 mg/mL PdCl.sub.2 aqueous solution is then added dropwise, and continuously stirred for 1 h at room temperature. 2 mL of 10 mg/mL formic acid aqueous solution is added dropwise under stirring conditions, continuously stirred at room temperature for 1 h, filtered and washed to neutrality, to obtain a nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst.

(13) An actual load of Pd in the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst prepared in this example is tested by using an atomic emission spectroscopy, to obtain a result of 0.59%, which is basically consistent with a theoretical load of the Pd.

(14) An X-ray diffraction test is performed on the nitrogen-doped porous carbon composite material prepared in this embodiment, and the results are shown in FIG. 1. As can be seen from FIG. 1, characteristic diffraction peaks of Pd metal can be clearly observed at 40.1° and 46.7°. A scanning electron microscopy test is performed on the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst prepared in this example, and the results are shown in FIG. 2. As can be seen from FIG. 2, a rich pore structure can be clearly observed. A transmission electron microscope test is performed on the nitrogen-doped porous carbon composite material prepared in this example, and the results are shown in FIG. 3. As can be seen from FIG. 3, Pd nanoparticles are uniformly dispersed in the nitrogen-doped porous carbon material, and have a particle size conforming to a normal distribution. The average particle size of the Pd nanoparticles is about 8 nm, and the content of Pd nanoparticles with a particle size less than 4 nm is extremely low.

Example 2

(15) 1 g of nitrogen-doped hierarchical-porous carbon material prepared in Example 1 is weighed, added to 60 mL of deionized water, stirred at room temperature, and slowly added with 100 mg/mL NaOH aqueous solution dropwise to adjust the pH value of the mixed solution to 9. 1 mL of 10 mg/mL Pd(NO.sub.3).sub.2 aqueous solution is then added dropwise, and continuously stirred for 1 h at room temperature. 2 mL of 15 mg/mL formic acid aqueous solution is added dropwise under stirring conditions, continuously stirred at room temperature for 1 h, filtered and washed to neutrality, to obtain a nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst.

(16) In contrast to Example 1, the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst prepared in this example is adjusted in the pH value of the mixed solution, the type of precursor salt, and the type and concentration of the reducing agent in the preparation process. The particle size of the Pd nanoparticles of the prepared catalyst conforms to the normal distribution, and the average particle size is about 6 nm, wherein the content of Pd nanoparticles with a particle size of less than 4 nm accounts for ˜10%, which is more than that of Example 1.

Example 3

(17) 1 g of nitrogen-doped hierarchical-porous carbon material prepared in Example 1 is weighed, added to 60 mL of deionized water, stirred at room temperature, and slowly added with 100 mg/mL NaOH aqueous solution dropwise to adjust the pH value of the mixed solution to 10. 1 mL of 10 mg/mL Pd(NH.sub.3).sub.4(NO.sub.3).sub.2 aqueous solution is then added dropwise, and continuously stirred for 1 h at room temperature. 2 mL of 20 mg/mL sodium borohydride aqueous solution is added dropwise under stirring conditions, continuously stirred at room temperature for 1 h, filtered and washed to neutrality, to obtain a nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst.

(18) In contrast to Example 1, the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst prepared in this example is adjusted in the type of precursor salt, and the type and concentration of the reducing agent in the preparation process. The particle size of the Pd nanoparticles of the prepared catalyst conforms to the normal distribution, and the average particle size is about 5 nm, wherein the content of Pd nanoparticles with a particle size of less than 4 nm accounts for ˜40%, which is more than that of Example 1.

Comparative Example 1

(19) 1 g of commercially available activated carbon material is weighed, added to 60 mL of deionized water, stirred at room temperature, and slowly added with 1 mL of 100 mg/mL PdCl.sub.2 solution, stirred for half an hour and then added with 100 mg/mL of NaOH aqueous solution to adjust the pH value of the mixed solution to 10, and then continuously stirred at room temperature for 1 h. 2 mL of 20 mg/mL formic acid aqueous solution is added dropwise under stirring conditions, continuously stirred at room temperature for 1 h, filtered and washed to neutrality, to obtain an activated carbon-loaded nano-Pd catalyst (referred to as a Pd/AC catalyst).

(20) In contrast to Example 1, the Pd/AC catalyst prepared in this comparative example is prepared by a conventional low-temperature liquid phase reduction method. That is, the addition orders of a Pd salt precursor and lye are exchanged, i.e., the Pd salt precursor is added first, and the pH of the solution is then adjusted.

(21) After testing, the Pd nanoparticles on the Pd/AC catalyst prepared in this comparative example have nonuniform particle sizes, and agglomerate. The Pd nanoparticles have an average particle size of about 5 nm, and are spherical or ellipsoidal, wherein the content of Pd nanoparticles with a particle size of less than 4 nm accounts for 35%, which is more than that of Example 1.

Comparative Example 2

(22) 1 g of nitrogen-doped hierarchical-porous carbon material prepared in Example 1 is weighed, added to 60 mL of deionized water, stirred at room temperature, added with 1 mL of 10 mg/mL PdCl.sub.2 aqueous solution, stirred for half an hour and then added with 100 mg/mL NaOH aqueous solution dropwise to adjust the pH value of the mixed solution to 10, and continuously stirred at room temperature for 1 h. 2 mL of 20 mg/mL formic acid aqueous solution is added dropwise under stirring conditions, continuously stirred at room temperature for 1 h, filtered and washed to neutrality, to obtain a nitrogen-doped hierarchical-porous carbon-loaded Pd/CN catalyst.

(23) The preparation method of the catalyst in Comparative Example 2 is the same as that in Comparative Example 1, but the nitrogen-doped hierarchical-porous carbon is used as a catalyst carrier. The Pd nano-particles on the prepared Pd/CN catalyst have a uniform particle size. The Pd nano-particles have an average particle size of about 2 nm, and are spherical or ellipsoidal.

Application Example 1

(24) A selective hydrogenation reaction of catalyzing 6-methyl-5-hepten-2-one (I) is specifically as follows: a 50 mL high pressure reaction kettle is used and added with 50 mg of the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst prepared in Example 1, 15 mmol of 6-methyl-5-hepten-2-one (I) serving as a substrate, and 10 mL of ethanol; 2 MPa of hydrogen is introduced; the reaction temperature is 30° C.; the reaction time is 4 h.

(25) After testing, a conversion rate of 6-methyl-5-hepten-2-one (I) is 100%, and the selectivity of 6-methyl-2-heptanone (II) is 99.9%.

Application Example 2

(26) A selective hydrogenation reaction of catalyzing 6-methyl-5-hepten-2-one (I) is specifically as follows: a 50 mL high pressure reaction kettle is used and added with 50 mg of the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst prepared in Example 2, 15 mmol of 6-methyl-5-hepten-2-one (I) serving as a substrate, and 10 mL of ethanol; 2 MPa of hydrogen is introduced; the reaction temperature is 30° C.; the reaction time is 4 h.

(27) After testing, a conversion rate of 6-methyl-5-hepten-2-one (I) is 100%, and the selectivity of 6-methyl-2-heptanone (II) is 98.9%.

Application Example 3

(28) A selective hydrogenation reaction of catalyzing 6-methyl-5-hepten-2-one (I) is specifically as follows: a 50 mL high pressure reaction kettle is used and added with 50 mg of the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst prepared in Example 3, 15 mmol of 6-methyl-5-hepten-2-one (I) serving as a substrate, and 10 mL of ethanol; 2 MPa of hydrogen is introduced; the reaction temperature is 30° C.; the reaction time is 4 h.

(29) After testing, a conversion rate of 6-methyl-5-hepten-2-one (I) is 100%, and the selectivity of 6-methyl-2-heptanone (II) is 96.9%.

Comparative Application Examples 1 to 2

(30) The process conditions are exactly the same as those of Application Example 1, except that the catalysts are respectively replaced with Pd/AC and Pd/CN catalysts prepared in Comparative Example 1 and Comparative Example 2 by the traditional low-temperature reduction method.

(31) After testing, the conversion rate and selectivity of the Pd/AC catalyst are 90% and 72%, respectively, and the conversion rate and selectivity of the Pd/CN catalyst are 95% and 90%, respectively.

(32) It can be seen that the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst prepared in Example 1 of the present invention is used in the selective hydrogenation reaction of unsaturated ketone, while maintaining the catalyst activity and greatly improving the selectivity.

Application Example 4

(33) The selective hydrogenation reaction of catalyzing 6,10-dimethyl-5-ene-2-undecanone (III) is specifically as follows: a 50 mL high pressure reaction kettle is used and added with 50 mg of the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst prepared in Example 1, 15 mmol of 6,10-dimethyl-5-ene-2-undecanone (III) serving as a substrate, and 10 mL of ethanol; 2 MPa of hydrogen is introduced; the reaction temperature is 30° C.; the reaction time is 4 h.

(34) After testing, the conversion rate of 6,10-dimethyl-5-ene-2-undecanone (III) is 100%, and the selectivity of 6,10-dimethyl-2-undecanone (IV) is 99.9%.

Application Example 5

(35) The selective hydrogenation reaction of catalyzing 6,10,14-trimethyl-5-ene-2-pentadecanone (V) is specifically as follows: a 50 mL high pressure reaction kettle is used and added with 50 mg of the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst prepared in Example 1, 15 mmol of 6,10,14-trimethyl-5-ene-2-pentadecanone (V) serving as a substrate, and 10 mL of ethanol; 2 MPa of hydrogen is introduced; the reaction temperature is 30° C.; the reaction time is 4 h.

(36) After testing, the conversion rate of 6,10,14-trimethyl-5-ene-2-pentadecanone (V) is 100%, and the selectivity of 6,10,14-trimethyl-2-pentadecanone (VI) is 99.8%.

Application Example 6

(37) The selective hydrogenation reaction of catalyzing 6-methyl-3,5-heptadiene-2-one (VII) is specifically as follows: a 50 mL high pressure reaction kettle is used and added with 50 mg of the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst prepared in Example 1, 15 mmol of 6-methyl-3,5-heptadiene-2-one (VII) serving as a substrate, and 10 mL of ethanol; 2 MPa of hydrogen is introduced; the reaction temperature is 30° C.; the reaction time is 4 h.

(38) After testing, the conversion rate of 6-methyl-3,5-heptadiene-2-one (VII) is 100%, and the selectivity of 6-methyl-2-heptanone (II) is 99.8%.

Application Example 7

(39) The selective hydrogenation reaction of catalyzing 6,10-dimethyl-5,9-diene-2-undecanone (VIII) is specifically as follows: a 50 mL high pressure reaction kettle is used and added with 50 mg of the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst prepared in Example 1, 15 mmol of 6,10-dimethyl-5,9-diene-2-undecanone (VIII) serving as a substrate, and 10 mL of ethanol; 2 MPa of hydrogen is introduced; the reaction temperature is 30° C.; the reaction time is 4 h.

(40) After testing, the conversion rate of 6,10-dimethyl-5,9-diene-2-undecanone (VIII) is 100%, and the selectivity of 6,10-dimethy-2-undecanone (IV) is 99.8%.

Application Example 8

(41) The selective hydrogenation reaction of catalyzing 6,10-dimethyl-3,5-diene-2-undecanone (IX) is specifically as follows: a 50 mL high pressure reaction kettle is used and added with 50 mg of the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst prepared in Example 1, 15 mmol of 6,10-dimethyl-3,5-diene-2-undecanone (IX) serving as a substrate, and 10 mL of ethanol; 2 MPa of hydrogen is introduced; the reaction temperature is 30° C.; the reaction time is 4 h.

(42) After testing, the conversion rate of 6,10-dimethyl-3,5-diene-2-undecanone (IX) is 100%, and the selectivity of 6,10-dimethy-2-undecanone (IV) is 99.9%.

Application Example 9

(43) The selective hydrogenation reaction of catalyzing 6,10,14-trimethyl-3,5-diene-2-pentadecanone (X) is specifically as follows: a 50 mL high pressure reaction kettle is used and added with 50 mg of the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst prepared in Example 1, 15 mmol of 6,10,14-trimethyl-3,5-diene-2-pentadecanone (X) serving as a substrate, and 10 mL of ethanol; 2 MPa of hydrogen is introduced; the reaction temperature is 30° C.; the reaction time is 4 h.

(44) After testing, the conversion rate of 6,10,14-trimethyl-3,5-diene-2-pentadecanone (X) is 100%, and the selectivity of 6,10,14-trimethyl-2-pentadecanone (VI) is 99.9%.

Application Example 10

(45) The selective hydrogenation reaction of catalyzing 6,10,14-trimethyl-5,9,13-triene-2-pentadecanone (XI) is specifically as follows: a 50 mL high pressure reaction kettle is used and added with 50 mg of the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst prepared in Example 1, 15 mmol of 6,10,14-trimethyl-5,9,13-triene-2-pentadecanone (XI) serving as a substrate, and 10 mL of ethanol; 2 MPa of hydrogen is introduced; the reaction temperature is 30° C.; the reaction time is 4 h.

(46) After testing, the conversion rate of 6,10,14-trimethyl-5,9,13-triene-2-pentadecanone (XI) is 100%, and the selectivity of 6,10,14-trimethyl-2-pentadecanone (VI) is 99.8%.

Application Example 11

(47) The selective hydrogenation reaction of catalyzing cis-3,7-dimethyl-2,6-diene-octanal (XII) is specifically as follows: a 50 mL high pressure reaction kettle is used and added with 50 mg of the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst prepared in Example 1, 15 mmol of cis-3,7-dimethyl-2,6-diene-octanal (XII) serving as a substrate, and 10 mL of ethanol; 2 MPa of hydrogen is introduced; the reaction temperature is 30° C.; the reaction time is 4 h.

(48) After testing, the conversion rate of the cis-3,7-dimethyl-2,6-diene-octanal (XII) is 100%, and the selectivity of the 3,7-dimethyl-octanal (XIII) is 99.6%.

Application Example 12

(49) The selective hydrogenation reaction of catalyzing trans-3,7-dimethyl-2,6-diene-octanal (XIV) is specifically as follows: a 50 mL high pressure reaction kettle is used and added with 50 mg of the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst prepared in Example 1, 15 mmol of trans-3,7-dimethyl-2,6-diene-octanal (XIV) serving as a substrate, and 10 mL of ethanol; 2 MPa of hydrogen is introduced; the reaction temperature is 30° C.; the reaction time is 4 h.

(50) After testing, the conversion rate of the trans-3,7-dimethyl-2,6-diene-octanal (XIV) is 100%, and the selectivity of the 3,7-dimethyl-octanal (XIII) is 99.8%.

Application Example 13

(51) The comparison of mechanical application performances of the selective hydrogenation reaction of catalyzing 6-methyl-3,5-heptadiene-2-one (VII) is specifically as follows: a double-kettle parallel experiment is adopted in the mechanical application of each catalyst. A 50 mL high pressure reaction kettle is used and respectively added with the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst in Example 1, 50 mg of the catalysts prepared in Comparative Example 1 and Comparative Example 2, 15 mmol of 6-methyl-3,5-heptadiene-2-one (VII) and 10 mL of ethanol; 2 MPa of hydrogen is introduced; the reaction temperature is 30° C.; the reaction time is 4 h. After the reaction, the catalysts in the two kettles are taken out by centrifugation, washed with ethanol for 3 times, and dried in vacuum at 40° C. The catalyst in one of the kettles is supplemented with the catalyst in the parallel experiment kettle and then continues to be used for the selective hydrogenation reaction of the 6-methyl-3,5-heptadiene-2-one (VII).

(52) The results of the mechanical application are shown in FIG. 7. It can be found that the performances of the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst of Example 1 are stable, and the activity and selectivity can still be maintained after 100 times of mechanical application. The activity and selectivity of the Pd/AC catalyst prepared in Comparative Example 1 decrease significantly with the increase in the number of mechanical applications. After 100 times of mechanical applications, the conversion rate and selectivity could only be maintained at about 50% and 60%, respectively. The conversion rate and selectivity of the Pd/CN catalyst prepared in Comparative Example 2 are maintained at initial values of approximately 90% and 95%.

Application Example 14

(53) The comparison of mechanical application performances of catalyzing the selective hydrogenation reaction of 6,10-dimethyl-3,5-diene-2-undecanone (IX) is specifically as follows: a double-kettle parallel experiment is adopted in the mechanical application of a catalyst. a 50 mL high pressure reaction kettle is used and added with 50 mg of the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst prepared in Example 1, 15 mmol of 6,10-dimethyl-3,5-diene-2-undecanone (IX) and 10 mL of ethanol; 2 MPa of hydrogen is introduced; the reaction temperature is 30° C.; the reaction time is 4 h. After the reaction, the catalysts in the two kettles are taken out by centrifugation, washed with ethanol 3 for times, and dried in vacuum at 40° C. The catalyst in one of the kettles is supplemented with the catalyst in the parallel experiment kettle and continues to be used for the selective hydrogenation reaction of the 6,10-dimethyl-3,5-diene-2-undecanone (IX).

(54) The results of the mechanical application are shown in FIG. 8. It can be found that the performances of the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst of Example 1 are stable, and the selectivity can still be maintained after 100 times of mechanical application, with only a slight decrease in activity.

Application Example 15

(55) The comparison of mechanical application performances of catalyzing the selective hydrogenation reaction of 6,10,14-trimethyl-3,5-diene-2-pentadecanone (X) is specifically as follows: a double-kettle parallel experiment is adopted in the mechanical application of a catalyst. a 50 mL high pressure reaction kettle is used and added with 50 mg of the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst prepared in Example 1, 15 mmol of 6,10,14-trimethyl-3,5-diene-2-pentadecanone (X) and 10 mL of ethanol; 2 MPa of hydrogen is introduced; the reaction temperature is 30° C.; the reaction time is 4 h. After the reaction, the catalysts in the two kettles are taken out by centrifugation, washed with ethanol for 3 times, and dried in vacuum at 40° C. The catalyst in one of the kettles is supplemented with the catalyst in the parallel experiment kettle and continues to be used for the selective hydrogenation reaction of the 6,10,14-Trimethyl-3,5-diene-2-pentadecanone (X).

(56) The results of the mechanical application are shown in FIG. 9. It can be found that the performances of the nitrogen-doped hierarchical-porous carbon-loaded nano-Pd catalyst of Example 1 are stable, and the selectivity can still be maintained after 100 times of mechanical application, with only a slight decrease in activity.

(57) The technical features of the above-described examples may be arbitrarily combined. For the sake of brevity of description, all possible combinations of the technical features in the above examples are not described. However, as long as there is no contradiction between the combinations of these technical features, they should be considered as the scope of the description.

(58) The above-described examples are merely illustrative of several embodiments of the present invention, and the description thereof is more specific and detailed, but is not to be construed as limiting the scope of the present invention. It should be noted that a number of variations and modifications may be made by those of ordinary skill in the art without departing from the concept of the present invention, all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the appended claims.