A metallic copper / organic ligand modified graphene oxide catalyst and its application in fatty aldehyde oxidation

Abstract

The invention discloses a metal copper / organic ligand modified graphene oxide catalyst and its application in fatty aldehyde oxidation, and relates to the technical field of catalyst preparation. The catalyst is prepared by the following steps: step S1, epoxy modified graphene oxide; step S2, organic ligand modified graphene oxide; step S3, metal copper salt composite and reduction. The metal copper / organic ligand modified graphene oxide catalyst has significant catalytic effect, high catalytic efficiency and good product selectivity.

Description

Technical Field

[0001] The invention relates to the technical field of catalyst preparation, and in particular to a metal copper / organic ligand modified graphene oxide catalyst and application thereof in the oxidation of fatty aldehydes. Background Art

[0002] In recent years, with the continuous development of industrialization, the chemical industry has become an indispensable part of promoting the development of the world economy. Catalysts are the core of the chemical industry and production processes. They are tools that efficiently and selectively achieve the formation and breaking of chemical bonds, and can transform chemicals into products with higher value. It can be seen that the development of catalysts with high catalytic efficiency and good catalytic effect is the key to improving product production efficiency.

[0003] 2-Ethylhexanoic acid, also known as isooctanoic acid, is an important fine chemical product. It is widely used in coatings, inks, plastics, rubber, petrochemicals, papermaking, cosmetics, aerospace, military and other fields. With the development of industry and agriculture, the demand for isooctanoic acid is also increasing year by year, and its economic status is also quite important. It is imperative to seek a catalyst for the efficient preparation of isooctanoic acid.

[0004] At present, a common method for preparing isooctanoic acid is to oxidize fatty aldehydes. This method has a reliable source of raw materials and is a continuous, fully enclosed process that is easy to scale up. However, the existing reaction catalysts for preparing isooctanoic acid by oxidizing fatty aldehydes have more or less defects such as being difficult to separate and handle, or having a cumbersome and highly corrosive preparation process, or having a complex process and unsatisfactory product selectivity.

[0005] For example, the Chinese invention patent with application number CN00129414.8 discloses a method for producing 2-ethylhexanoic acid, which is prepared by oxidation reaction of a reaction mixture formed by a raw material containing 2-ethylhexanal and a solvent with an oxygen-containing gas under the action of a catalyst at 0 to 30°C. The catalyst is Mn(Ac)2 or KAc or Cu(Ac)2 or a mixture of all or part of them in any ratio. The invention has high selectivity and high yield of 2-ethylhexanoic acid, and low cost of catalyst use. However, the optimal reaction temperature disclosed in the patent is 0-15°C, and its highest selectivity is 94.9%, which still has room for improvement, and its engineering temperature control energy consumption is high, and industrialization is not ideal.

[0006] Therefore, the development of a fatty aldehyde oxidation catalyst with significant catalytic effect, high catalytic efficiency and good product selectivity meets market demand, has broad market value and application prospects, and is of great significance to promoting the development of the field of preparing isooctanoic acid by fatty aldehyde oxidation. Summary of the invention

[0007] The main purpose of the present invention is to provide a metal copper / organic ligand modified graphene oxide catalyst with significant catalytic effect, high catalytic efficiency and good product selectivity, and its application in the oxidation of fatty aldehydes.

[0008] To achieve the above object, the present invention provides a metal copper / organic ligand modified graphene oxide catalyst, which is prepared by the following steps:

[0009] Step S1, epoxy-modified graphene oxide: dispersing graphene oxide in ethanol, adding an epoxy-containing coupling agent thereto, stirring and reacting at 30-50° C. for 3-5 hours, and then removing the ethanol by rotary evaporation to obtain epoxy-modified graphene oxide;

[0010] Step S2, organic ligand modified graphene oxide: meso-tetramethyl-meso-tetraaminophenylcalix[4]pyrrole, epoxy-modified graphene oxide prepared in step S1, 2,3-epoxypropyltrimethylammonium chloride, and an alkaline catalyst are added to a high boiling point solvent, stirred and reacted at 60-80° C. for 4-6 hours, after rotary evaporation to remove the solvent, centrifuged and washed with water for 3-6 times, and then dried in a vacuum drying oven at 80-90° C. to constant weight;

[0011] Step S3, metal copper salt complexing and reduction: add the organic ligand modified graphene oxide, cupric chloride and dipotassium tetrachlorocuprate dihydrate prepared in step S2 into water, stir and react at 50-60°C for 4-6 hours, then add reducing agent NaBH4, stir and react at 90-98°C for 3-5 hours, wash with water by centrifugation and dry in an oven at 85-95°C to constant weight.

[0012] Preferably, the mass ratio of graphene oxide, ethanol and epoxy-containing coupling agent in step S1 is 1: (3-5): (0.1-0.3).

[0013] Preferably, the graphene oxide is Liugong LG-1401 graphene oxide.

[0014] Preferably, the epoxy-containing coupling agent is silane coupling agent KH560.

[0015] Preferably, the mass ratio of meso-tetramethyl-meso-tetraaminophenylcalix[4]pyrrole, epoxy-modified graphene oxide, 2,3-epoxypropyltrimethylammonium chloride, alkaline catalyst and high boiling point solvent in step S2 is (3-5): 1: (0.3-0.5): (0.1-0.3): (15-25).

[0016] Preferably, the preparation method of the meso-tetramethyl-meso-tetraaminophenylcalix[4]pyrrole is described in: Guo Yong, Shao Shijun, He Lijun, et al. Synthesis and Characterization of Meso-tetramethyl-meso-tetraaminophenylcalix[4]pyrrole [J]. Chemical Reagents, 2002(6):344-345.

[0017] Preferably, the alkaline catalyst is at least one of sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate.

[0018] Preferably, the high boiling point solvent is at least one of dimethyl sulfoxide, N,N-dimethylformamide and N-methylpyrrolidone.

[0019] Preferably, the mass ratio of the organic ligand-modified graphene oxide, cupric chloride, dipotassium tetrachlorocuprate dihydrate, water, and NaBH4 in step S3 is (3-5):(0.4-0.8):(0.1-0.3):(15-25):(0.8-1.2).

[0020] Another object of the present invention is to provide an application of the metallic copper / organic ligand modified graphene oxide catalyst in the oxidation of fatty aldehydes.

[0021] Due to the application of the above technical solution, the present invention has the following beneficial effects:

[0022] (1) The metal copper / organic ligand modified graphene oxide catalyst disclosed in the present invention has a simple preparation process, convenient operation and control, high preparation efficiency and finished product qualification rate, is suitable for continuous large-scale production, and has a high value for promotion and application.

[0023] (2) The metal copper / organic ligand modified graphene oxide catalyst disclosed in the present invention contains graphene, metal copper, quaternary ammonium salt and organic ligand structure at the same time, which work together to effectively improve the catalytic effect and catalytic efficiency and enhance the reaction selectivity.

[0024] (3) The metal copper / organic ligand modified graphene oxide catalyst disclosed in the present invention can react with the amino groups on the epoxy-modified graphene oxide and 2,3-epoxypropyltrimethylammonium chloride to form an epoxy ring-opening reaction, thereby combining these effective components. The catalytic stability of the catalyst is improved, the loss of catalyst components is effectively delayed, thereby extending its service life and improving the conversion rate and selectivity of the catalyst in the oxidation reaction of fatty aldehydes. At the same time, 2,3-epoxypropyltrimethylammonium chloride can undergo ion exchange with dipotassium tetrachlorocuprate dihydrate, so that the metal copper can be dispersed more evenly in the catalyst. DETAILED DESCRIPTION

[0025] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art may think of other obvious variations. Example 1

[0026] A metal copper / organic ligand modified graphene oxide catalyst is prepared by the following steps:

[0027] Step S1, epoxy-modified graphene oxide: 10 g of graphene oxide was dispersed in 30 g of ethanol, and 1 g of an epoxy-containing coupling agent was added thereto, and the mixture was stirred and reacted at 30° C. for 3 h, and then the ethanol was removed by rotary evaporation to obtain epoxy-modified graphene oxide;

[0028] Step S2, organic ligand modified graphene oxide: 30 g of meso-tetramethyl-meso-tetraaminophenylcalix[4]pyrrole, 10 g of epoxy-modified graphene oxide prepared in step S1, 3 g of 2,3-epoxypropyltrimethylammonium chloride, and 1 g of alkaline catalyst are added to a high boiling point solvent 150, stirred and reacted at 60° C. for 4 hours, the solvent was removed by rotary evaporation, and the mixture was washed by centrifugation with water for 3 times, and then dried in a vacuum drying oven at 80° C. to constant weight;

[0029] Step S3, metal copper salt complexation and reduction: add 30 g of organic ligand-modified graphene oxide prepared in step S2, 4 g of copper chloride, and 1 g of dipotassium tetrachlorocuprate dihydrate to 150 g of water, stir and react at 50° C. for 4 hours, then add 48 g of reducing agent NaBH, stir and react at 90° C. for 3 hours, wash with water by centrifugation, and dry in an oven at 85° C. to constant weight.

[0030] The graphene oxide is Liugong LG-1401 graphene oxide; the epoxy-containing coupling agent is silane coupling agent KH560. The preparation method of Meso-tetramethyl-meso-tetraaminophenyl cup [4] pyrrole, see: Guo Yong, Shao Shijun, He Lijun, et al. Synthesis and Characterization of Meso-tetramethyl-meso-tetraaminophenyl cup [4] pyrrole [J]. Chemical Reagents, 2002 (6): 344-345; the alkaline catalyst is sodium hydroxide; the high boiling point solvent is dimethyl sulfoxide.

[0031] An application of the metallic copper / organic ligand modified graphene oxide catalyst in the oxidation of fatty aldehydes. Example 2

[0032] A metal copper / organic ligand modified graphene oxide catalyst is prepared by the following steps:

[0033] Step S1, epoxy-modified graphene oxide: 10 g of graphene oxide was dispersed in 35 g of ethanol, and 1.5 g of an epoxy-containing coupling agent was added thereto, and the mixture was stirred and reacted at 35° C. for 3.5 h, and then the ethanol was removed by rotary evaporation to obtain epoxy-modified graphene oxide;

[0034] Step S2, organic ligand modified graphene oxide: 35 g of meso-tetramethyl-meso-tetraaminophenylcalix[4]pyrrole, 10 g of epoxy-modified graphene oxide prepared in step S1, 3.5 g of 2,3-epoxypropyltrimethylammonium chloride, and 1.5 g of alkaline catalyst were added to 170 g of a high boiling point solvent, stirred and reacted at 65° C. for 4.5 hours, the solvent was removed by rotary evaporation, and the mixture was washed by centrifugation with water for 4 times, and then dried in a vacuum drying oven at 83° C. to constant weight;

[0035] Step S3, metal copper salt complexation and reduction: 35 g of the organic ligand-modified graphene oxide prepared in step S2, 5 g of copper chloride, and 1.5 g of dipotassium tetrachlorocuprate dihydrate were added to water, stirred and reacted at 52° C. for 4.5 hours, and then 49 g of the reducing agent NaBH was added, stirred and reacted at 93° C. for 3.5 hours, and the mixture was centrifuged and washed with water and dried in an oven at 88° C. to constant weight.

[0036] The graphene oxide is Liugong LG-1401 graphene oxide; the epoxy-containing coupling agent is silane coupling agent KH560. The preparation method of Meso-tetramethyl-meso-tetraaminophenyl cup [4] pyrrole, see: Guo Yong, Shao Shijun, He Lijun, et al. Synthesis and Characterization of Meso-tetramethyl-meso-tetraaminophenyl cup [4] pyrrole [J]. Chemical Reagents, 2002 (6): 344-345; the alkaline catalyst is potassium hydroxide; the high boiling point solvent is N, N-dimethylformamide.

[0037] An application of the metallic copper / organic ligand modified graphene oxide catalyst in the oxidation of fatty aldehydes. Example 3

[0038] A metal copper / organic ligand modified graphene oxide catalyst is prepared by the following steps:

[0039] Step S1, epoxy-modified graphene oxide: 10 g of graphene oxide was dispersed in 40 g of ethanol, and 2 g of an epoxy-containing coupling agent was added thereto, and the mixture was stirred and reacted at 40° C. for 4 h, and then the ethanol was removed by rotary evaporation to obtain epoxy-modified graphene oxide;

[0040] Step S2, organic ligand modified graphene oxide: 40 g of meso-tetramethyl-meso-tetraaminophenylcalix[4]pyrrole, 10 g of epoxy-modified graphene oxide prepared in step S1, 4 g of 2,3-epoxypropyltrimethylammonium chloride, and 2 g of alkaline catalyst were added to 200 g of a high boiling point solvent, stirred and reacted at 70° C. for 5 hours, the solvent was removed by rotary evaporation, and the mixture was washed by centrifugation with water for 5 times, and then dried in a vacuum drying oven at 85° C. to constant weight;

[0041] Step S3, metal copper salt complexing and reduction: add 40 g of organic ligand-modified graphene oxide prepared in step S2, 6 g of copper chloride, and 2 g of dipotassium tetrachlorocuprate dihydrate to 200 g of water, stir and react at 55° C. for 5 hours, then add 10 g of reducing agent NaBH4, stir and react at 95° C. for 4 hours, wash with water by centrifugation, and dry in an oven at 90° C. to constant weight.

[0042] The graphene oxide is Liugong LG-1401 graphene oxide; the epoxy-containing coupling agent is silane coupling agent KH560. The preparation method of Meso-tetramethyl-meso-tetraaminophenyl cup [4] pyrrole can be found in: Guo Yong, Shao Shijun, He Lijun, et al. Synthesis and Characterization of Meso-tetramethyl-meso-tetraaminophenyl cup [4] pyrrole [J]. Chemical Reagents, 2002 (6): 344-345; the alkaline catalyst is sodium carbonate; the high boiling point solvent is N-methylpyrrolidone.

[0043] An application of the metallic copper / organic ligand modified graphene oxide catalyst in the oxidation of fatty aldehydes. Example 4

[0044] A metal copper / organic ligand modified graphene oxide catalyst is prepared by the following steps:

[0045] Step S1, epoxy-modified graphene oxide: 10 g of graphene oxide was dispersed in 45 g of ethanol, and 2.5 g of an epoxy-containing coupling agent was added thereto, and the mixture was stirred and reacted at 45° C. for 4.5 h, and then the ethanol was removed by rotary evaporation to obtain epoxy-modified graphene oxide;

[0046] Step S2, organic ligand modified graphene oxide: 45 g of meso-tetramethyl-meso-tetraaminophenylcalix[4]pyrrole, 10 g of epoxy-modified graphene oxide prepared in step S1, 4.5 g of 2,3-epoxypropyltrimethylammonium chloride, and 2.5 g of alkaline catalyst were added to 230 g of a high boiling point solvent, stirred and reacted at 75° C. for 5.5 hours, the solvent was removed by rotary evaporation, and the mixture was washed by centrifugation with water for 5 times, and then dried in a vacuum drying oven at 88° C. to constant weight;

[0047] Step S3, metal copper salt complexing and reduction: 45 g of organic ligand-modified graphene oxide prepared in step S2, 7.5 g of cupric chloride, and 2.5 g of dipotassium tetrachlorocuprate dihydrate are added to 230 g of water, and the mixture is stirred and reacted at 58° C. for 5.5 hours. Then, 11 g of reducing agent NaBH4 is added, and the mixture is stirred and reacted at 96° C. for 4.5 hours. The mixture is washed by centrifugation with water and dried in an oven at 93° C. to constant weight.

[0048] The graphene oxide is Liugong LG-1401 graphene oxide; the epoxy-containing coupling agent is silane coupling agent KH560. The preparation method of Meso-tetramethyl-meso-tetraaminophenyl cup [4] pyrrole, see: Guo Yong, Shao Shijun, He Lijun, et al. Synthesis and Characterization of Meso-tetramethyl-meso-tetraaminophenyl cup [4] pyrrole [J]. Chemical Reagents, 2002 (6): 344-345; the alkaline catalyst is a mixture of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate in a mass ratio of 1:2:1:1; the high boiling point solvent is a mixture of dimethyl sulfoxide, N,N-dimethylformamide, N-methylpyrrolidone in a mass ratio of 1:3:2.

[0049] An application of the metallic copper / organic ligand modified graphene oxide catalyst in the oxidation of fatty aldehydes. Example 5

[0050] A metal copper / organic ligand modified graphene oxide catalyst is prepared by the following steps:

[0051] Step S1, epoxy-modified graphene oxide: 10 g of graphene oxide was dispersed in 50 g of ethanol, and 3 g of an epoxy-containing coupling agent was added thereto, and the mixture was stirred and reacted at 50° C. for 5 h, and then the ethanol was removed by rotary evaporation to obtain epoxy-modified graphene oxide;

[0052] Step S2, organic ligand modified graphene oxide: 50 g of meso-tetramethyl-meso-tetraaminophenylcalix[4]pyrrole, 10 g of epoxy-modified graphene oxide prepared in step S1, 5 g of 2,3-epoxypropyltrimethylammonium chloride, and 3 g of alkaline catalyst were added to 250 g of a high boiling point solvent, stirred and reacted at 80° C. for 6 hours, the solvent was removed by rotary evaporation, and the mixture was washed by centrifugation with water for 6 times, and then dried in a vacuum drying oven at 90° C. to constant weight;

[0053] Step S3, metal copper salt complexation and reduction: 50 g of the organic ligand-modified graphene oxide prepared in step S2, 8 g of copper chloride, and 3 g of dipotassium tetrachlorocuprate dihydrate were added to 250 g of water, and stirred for reaction at 60° C. for 6 hours. Then 12 g of reducing agent NaBH4 was added, and stirred for reaction at 98° C. for 5 hours. The mixture was washed by centrifugation with water and dried in an oven at 95° C. to constant weight.

[0054] The graphene oxide is Liugong LG-1401 graphene oxide; the epoxy-containing coupling agent is silane coupling agent KH560. The preparation method of Meso-tetramethyl-meso-tetraaminophenyl cup [4] pyrrole can be found in: Guo Yong, Shao Shijun, He Lijun, et al. Synthesis and Characterization of Meso-tetramethyl-meso-tetraaminophenyl cup [4] pyrrole [J]. Chemical Reagents, 2002 (6): 344-345; the alkaline catalyst is potassium carbonate; the high boiling point solvent is dimethyl sulfoxide.

[0055] An application of the metallic copper / organic ligand modified graphene oxide catalyst in the oxidation of fatty aldehydes.

[0056] Comparative Example 1

[0057] A metal copper / organic ligand modified graphene oxide catalyst is substantially the same as Example 1, except that 2,3-epoxypropyltrimethylammonium chloride is not added.

[0058] Comparative Example 2

[0059] A metallic copper / organic ligand modified graphene oxide catalyst is substantially the same as Example 1, except that dipotassium tetrachlorocuprate dihydrate is not added.

[0060] In order to further illustrate the beneficial technical effects of the metal copper / organic ligand modified graphene oxide catalyst prepared in each embodiment of the present invention, the metal copper / organic ligand modified graphene oxide catalyst prepared in Examples 1-5 and Comparative Examples 1-2 was subjected to relevant performance tests. The test results are shown in Table 1. The test method is as follows: in a dry 1L three-necked flask, isooctyl aldehyde (160g, 1.25mol) and solvent 2-ethylhexanoic acid 160g, metal copper / organic ligand modified graphene oxide catalyst 6.4mg were added, and then placed in a water bath, mechanically stirred under a nitrogen atmosphere, and after the temperature rose to 20°C, air was introduced at a flow rate of 11.9g / h. The reaction temperature was maintained at 20-25°C by adding cooling water to the water bath. After 8h of reaction, the reaction solution was centrifuged and filtered, the catalyst was recovered, and sampling was performed for GC analysis. For the analytical instrument and method, the calculation formula of conversion rate, selectivity and yield, please refer to CN108250069B.

[0061] Table 1

[0062] project Conversion rate of isooctylaldehyde Selectivity of 2-ethylhexanoic acid Yield unit % % % Example 1 99.5 98.7 98.2 Example 2 99.7 99.0 98.7 Example 3 99.8 99.4 99.2 Example 4 99.9 99.6 99.5 Example 5 99.9 99.7 99.6 Comparative Example 1 98.7 98.2 96.9 Comparative Example 2 98.3 98.0 96.3

[0063] As can be seen from Table 1, the metal copper / organic ligand modified graphene oxide catalyst disclosed in the embodiment of the present invention has a better catalytic effect than the comparative example product; the addition of 2,3-epoxypropyltrimethylammonium chloride and dipotassium tetrachlorocuprate dihydrate is beneficial to improving the above performance.

[0064] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A metallic copper / organic ligand modified graphene oxide catalyst, characterized in that: It is made by the following steps: Step S1, epoxy-modified graphene oxide: dispersing graphene oxide in ethanol, adding an epoxy-containing coupling agent thereto, stirring and reacting at 30-50° C. for 3-5 hours, and then removing the ethanol by rotary evaporation to obtain epoxy-modified graphene oxide; Step S2, organic ligand modified graphene oxide: meso-tetramethyl-meso-tetraaminophenylcalix[4]pyrrole, epoxy-modified graphene oxide prepared in step S1, 2,3-epoxypropyltrimethylammonium chloride, and an alkaline catalyst are added to a high boiling point solvent, stirred and reacted at 60-80° C. for 4-6 hours, the solvent is removed by rotary evaporation, and the mixture is centrifuged and washed with water for 3-6 times, and then dried in a vacuum drying oven at 80-90° C. to constant weight; Step S3, metal copper salt complexing and reduction: add the organic ligand modified graphene oxide, cupric chloride and dipotassium tetrachlorocuprate dihydrate prepared in step S2 into water, stir and react at 50-60°C for 4-6 hours, then add reducing agent NaBH4, stir and react at 90-98°C for 3-5 hours, wash with water by centrifugation and dry in an oven at 85-95°C to constant weight.

2. The metallic copper / organic ligand modified graphene oxide catalyst according to claim 1, characterized in that: The mass ratio of graphene oxide, ethanol and epoxy-containing coupling agent in step S1 is 1: (3-5): (0.1-0.3).

3. The metallic copper / organic ligand modified graphene oxide catalyst according to claim 1, characterized in that: The epoxy-containing coupling agent is silane coupling agent KH560.

4. The metallic copper / organic ligand modified graphene oxide catalyst according to claim 1, characterized in that: The mass ratio of meso-tetramethyl-meso-tetraaminophenylcalix[4]pyrrole, epoxy-modified graphene oxide, 2,3-epoxypropyltrimethylammonium chloride, alkaline catalyst and high boiling point solvent in step S2 is (3-5): 1: (0.3-0.5): (0.1-0.3): (15-25).

5. The metallic copper / organic ligand modified graphene oxide catalyst according to claim 1, characterized in that: The alkaline catalyst is at least one of sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate.

6. The metallic copper / organic ligand modified graphene oxide catalyst according to claim 1, characterized in that: The high boiling point solvent is at least one of dimethyl sulfoxide, N,N-dimethylformamide and N-methylpyrrolidone.

7. The metallic copper / organic ligand modified graphene oxide catalyst according to claim 1, characterized in that: The mass ratio of the organic ligand-modified graphene oxide, cupric chloride, dipotassium tetrachlorocuprate dihydrate, water, and NaBH4 in step S3 is (3-5): (0.4-0.8): (0.1-0.3): (15-25): (0.8-1.2).

8. Use of the metallic copper / organic ligand modified graphene oxide catalyst according to any one of claims 1 to 7 in the oxidation of fatty aldehydes.