CN114904556A - Preparation method of benzyl alcohol selective oxidation heterogeneous catalyst under solvent-free oxygen condition - Google Patents

Preparation method of benzyl alcohol selective oxidation heterogeneous catalyst under solvent-free oxygen condition Download PDF

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CN114904556A
CN114904556A CN202210657442.8A CN202210657442A CN114904556A CN 114904556 A CN114904556 A CN 114904556A CN 202210657442 A CN202210657442 A CN 202210657442A CN 114904556 A CN114904556 A CN 114904556A
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catalyst
benzyl alcohol
preparation
selective oxidation
heterogeneous catalyst
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许杰
李春芫
杜娟
王非
柳娜
薛冰
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Changzhou University
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    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
    • B01J27/24—Nitrogen compounds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/30—Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
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    • C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
    • C07C45/27—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation
    • C07C45/32—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with molecular oxygen
    • C07C45/37—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with molecular oxygen of >C—O—functional groups to >C=O groups
    • C07C45/38—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with molecular oxygen of >C—O—functional groups to >C=O groups being a primary hydroxyl group
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Abstract

The patent belongs to the field of solid catalyst preparation and application, and relates to a preparation method of a heterogeneous catalyst for selective oxidation of benzyl alcohol under the condition of no solvent oxygen. The catalyst is prepared by roasting cyanamide, dicyanodiamine or melamine precursor to obtain graphite phase carbon nitride (g-C) 3 N 4 ) A material; then g-C is added 3 N 4 Roasting in a certain atmosphere to obtain exfoliated graphite phase carbon nitride (eg-C) 3 N 4 ) A material. PdCl 2 By impregnation and NaBH 4 Reduction to obtain the supported Pd catalyst (Pd/eg-C) 3 N 4 ). The catalyst is applied to the selective oxidation reaction of benzyl alcohol under the condition of no solvent oxygen, and the yield of benzaldehyde can reach 80-95%. After the reaction is finished, the reaction system is subjected to simple centrifugation or filtration,thus realizing catalyst recovery and product separation.

Description

Preparation method of benzyl alcohol selective oxidation heterogeneous catalyst under solvent-free oxygen condition
Technical Field
The invention belongs to the field of heterogeneous catalysis, and particularly relates to a preparation method of a supported heterogeneous catalyst for synthesizing benzaldehyde by selective oxidation of benzyl alcohol under the condition of no solvent oxygen.
Background
Benzaldehyde is an aromatic compound commonly used in industry, and has extremely wide application in the aspects of raw material synthesis, medicines, spices, pesticides and the like. The industrially common method for preparing benzyl alcohol is benzyl chloride hydrolysis, which employs toluene and chlorine as raw materials, chlorinates the side chain of toluene under appropriate conditions, and then hydrolyzes to obtain benzaldehyde. The industrial process of the method is complicated, the pollution is high, and the obtained benzaldehyde contains chloride ions, so that the later application is influenced. In addition, the direct oxidation of toluene uses toluene as the starting material in KMnO 4 、K 2 CrO 4 Under the action of an equal-strength oxidant, toluene is oxidized to benzaldehyde in one step. Although this method is large in supply amount and low in cost, there are problems that the product is easily excessively oxidized and contains metal ion impurities. Selective oxidation of benzyl alcohol using H 2 O 2 、O 2 And the like as an oxygen source, and the benzyl alcohol is oxidized into benzaldehyde under the action of a catalyst, so that compared with the two methods, the method is more green and clean, environment-friendly and simple in process conditions, and has a better industrial application prospect.
From the environmental point of view, O is developed 2 The catalyst which is an oxygen source and catalyzes the oxidation of the benzyl alcohol under the solvent-free condition has higher research and application significance. The catalysts reported at present are mainly supported catalysts which are used for supporting noble metals (such as Pd, Pt and Au).
Patent CN108772087A discloses a Pd-based catalyst for catalyzing selective oxidation of benzyl alcohol under solvent-free conditions. The catalyst is prepared by taking nitrogen-containing ordered mesoporous carbon (NOMC) as a carrier through impregnation and reduction of loaded Pd. Although the catalyst has a high catalytic effect, the preparation of the NOMC carrier adopts a soft template method, and the preparation process is complicated. Patent CN113042089A reports that carbon nitride is used as a carrier to load Pd for catalyzing the selective oxidation of benzyl alcohol to prepare benzaldehyde, the catalyst has short preparation period and simple method, but an organic solvent (such as toluene) is required in the reaction process. Patent CN101648137B discloses a metal carrier supported gold catalyst for selective oxidation of benzyl alcohol, but the reaction conditions required by the reaction are high and the catalyst is poor in recycling effect.
Graphite phase carbon nitride (g-C) 3 N 4 ) As a novel nitrogen-containing carbon material with a graphite-like structure, abundant nitrogen-containing functional groups can load and disperse metal nanoparticles. In another aspect, g-C 3 N 4 The distribution and content of the various nitrogen-containing functional groups on the surface have an important relationship with the dispersion degree of the catalyst active components. Therefore, the invention prepares a series of different eg-C by adjusting the preparation conditions 3 N 4 A support, synthesizing a Pd-supported catalyst (Pd/eg-C) 3 N 4 ) The method is applied to the selective oxidation reaction of the benzyl alcohol taking oxygen without solvent as an oxygen source.
Disclosure of Invention
The invention aims to solve the technical problem of designing a preparation method of a supported heterogeneous catalyst with high activity aiming at the selective oxidation reaction of benzyl alcohol taking oxygen as an oxygen source under the condition of no solution.
A method for preparing a heterogeneous catalyst for selective oxidation of benzyl alcohol under the condition of no solvent oxygen comprises the following steps:
(1) graphite phase carbon nitride (g-C) 3 N 4 ) Preparation of the material: baking a certain amount of cyanamide, dicyanodiamine or melamine precursor in the atmosphere of nitrogen (N) or air (A) at a certain temperature for a period of time to obtain g-C 3 N 4 A material;
(2) exfoliated graphite phase carbon nitride (eg-C) 3 N 4 ) Preparation of the material: a certain amount of g-C 3 N 4 Calcining the material in nitrogen (N) or air (A) atmosphere at a certain temperature for a certain period of time to obtain eg-C 3 N 4 A material. The suffix of the material represents the atmosphere, eg-C 3 N 4 -AN represents the preparation atmosphere and the stripping atmosphere of the material as air and nitrogen, respectively;
(3) preparation of supported Pd heterogeneous catalyst: 0.2 part by mass of eg-C 3 N 4 Adding into 20 parts by mass of water, and ultrasonically stirring to obtain eg-C 3 N 4 Uniformly dispersing in water; then, PdCl was added dropwise to the above liquid under stirring 2 Wherein Pd comprises eg-C 3 N 4 The mass percentage of the component (A) is 1-4%; adding excessive NaBH into the mixed solution 4 Solution, reacting NaBH 4 PdCl 2 All are reduced to Pd; filtering the obtained mixed solution, washing the mixed solution for many times by distilled water, and drying the mixed solution to obtain the heterogeneous catalyst which is recorded as Pd/eg-C 3 N 4 。
As a limitation to the invention, in the preparation method, the precursor in the step (1) is preferably dicyandiamide or melamine;
in the preparation method, the roasting temperature in the step (1) is 500-600 ℃;
in the preparation method, the roasting time in the step (1) is 2-8 hours, and preferably 2-4 hours.
In the preparation method, the roasting temperature in the step (2) is 450-550 ℃;
in the preparation method, the roasting time in the step (2) is 2-4 hours.
The catalyst obtained according to the technical scheme is suitable for normal pressure reaction without solvent (namely, the reaction liquid only contains benzyl alcohol) and oxygen as an oxidant.
The application process comprises the steps of adding benzyl alcohol and Pd/eg-C into a reaction vessel such as a flask with condensation reflux 3 N 4 Introducing oxygen (the flow rate is 10-40mL/min), and setting the reaction time at a certain reaction temperature.
In the application process, the catalytic reaction temperature is 85-100 ℃.
The reaction time of the application process is 1 to 10 hours, and preferably 6 to 8 hours.
After adopting the technical scheme, compared with the prior art, the invention has the beneficial effects that: the catalyst has the advantages of simple preparation, high catalytic activity in solvent-free reaction and the like, and after the reaction is finished, the catalyst recovery and product separation can be realized by simple centrifugation or filtration of a reaction system.
Drawings
FIG. 1 shows 2.5Pd/eg-C obtained in example 5 3 N 4 -X-ray diffraction pattern of NN catalyst. The catalyst has weak diffraction peak corresponding to g-C at 2 theta 13.1 DEG 3 N 4 The layers of the structure are stacked, i.e., (100) crystal planes. And a relatively clear diffraction peak at 27.3 ℃ corresponding to g-C 3 N 4 The interlaminar stacking structure of the structure, namely the (002) crystal face. The 39.5 ° and 45.5 ° diffraction peaks were ascribed to metallic palladium (Pd) 0 ) The (111) and (200) crystal planes of (a).
FIG. 2 is the 2.5Pd/eg-C obtained in example 5 3 N 4 -transmission electron microscopy of AN catalyst. As can be seen, the Pd particles are uniformly distributed on the surface of the catalyst.
Detailed Description
The invention will be further described in the following examples, but it is to be understood that these examples are for illustrative purposes only and are not to be construed as limiting the practice of the invention.
Example 1
(1) Catalyst preparation
6g of cyanamide is calcined at 500 ℃ for 8h in nitrogen to obtain g-C 3 N 4 -a N material; 2g of g-C 3 N 4 Roasting the-N material at 450 ℃ for 4h in nitrogen to obtain eg-C 3 N 4 -an NN material. 0.2 part by mass of eg-C 3 N 4 -NN was added to 20 parts by mass of water, and uniformly dispersed in the water by ultrasonic and stirring. Then, PdCl was added dropwise to the above liquid under stirring 2 (control Pd to be eg-C) 3 N 4 The mass percentage of (b) is 2%). Adding excessive NaBH into the mixed solution 4 Solution (excess means NaBH 4 Can convert PdCl into 2 All reduced to Pd). And filtering the mixed solution, washing the mixed solution for many times by using distilled water, and drying the mixed solution to obtain the catalyst.
(2) Catalytic reaction
A reaction vessel such as a flask equipped with a condensing reflux was charged with 30g of a catalyst and 4mL of benzyl alcohol, and reacted at a reaction temperature of 85 ℃ for 10 hours while passing oxygen (flow rate: 30 mL/min).
(3) Catalyst and product separation
After the catalytic reaction was completed, the reactor was rapidly cooled to room temperature. And slowly opening an air valve to exhaust the air in the air valve. Taking out the mixture of the reaction liquid and the catalyst in the reactor, and centrifuging or filtering to separate the catalyst and the reaction liquid. The isolated catalyst was washed with 20mL of ethanol for 30 minutes and then filtered. After repeating the above step for 3 times, the catalyst obtained by filtration was placed in a forced air oven and heated at 100 ℃ for 4 hours to obtain a recovered catalyst.
(4) Product analysis
The gas chromatography uses nitrogen as carrier gas, and is equipped with FFAP type capillary chromatographic column with column length of 30m and hydrogen ion flame detector. The vaporizer and detector temperatures were 250 ℃. The column box temperature program was as follows: the mixture is kept at 80 ℃ for 2 minutes, and then heated to 160 ℃ at a heating rate of 20 ℃/min, and kept for 2 minutes. The product was analyzed by gas chromatography, and the yield of benzaldehyde was 85%.
Example 2
(1) Catalyst preparation
6g of dicyanodiamine is roasted in air at 550 ℃ for 6h to obtain g-C 3 N 4 -a material; 2g of g-C 3 N 4 The material-A is roasted in air at 500 ℃ for 3h to obtain eg-C 3 N 4 -AA material. 0.2 part by mass of eg-C 3 N 4 -AA is added to 20 parts by mass of water and uniformly dispersed in the water by ultrasonic and stirring. Then, PdCl was added dropwise to the above liquid under stirring 2 (controlling Pd to be eg-C) 3 N 4 The mass percentage of (b) is 3%). Adding excessive NaBH into the mixed solution 4 Solution (excess means NaBH 4 Can convert PdCl into 2 All reduced to Pd). And filtering the mixed solution, washing the mixed solution for many times by using distilled water, and drying the mixed solution to obtain the catalyst.
(2) Catalytic reaction
A reaction vessel such as a flask with a condensing reflux was charged with 30g of a catalyst and 4mL of benzyl alcohol, and reacted at a reaction temperature of 100 ℃ for 4 hours by introducing oxygen (flow rate: 10 mL/min).
(3) Catalyst and product separation
After the catalytic reaction was completed, the reactor was rapidly cooled to room temperature. And slowly opening an air valve to exhaust the air in the air valve. Taking out the mixture of the reaction liquid and the catalyst in the reactor, and centrifuging or filtering to separate the catalyst and the reaction liquid. The isolated catalyst was washed with 20mL of ethanol for 30 minutes and then filtered. After repeating the above step for 3 times, the catalyst obtained by filtration was placed in a forced air oven and heated at 100 ℃ for 4 hours to obtain a recovered catalyst.
(4) Product analysis
The gas chromatography uses nitrogen as carrier gas, and is equipped with FFAP type capillary chromatographic column with column length of 30m and hydrogen ion flame detector. The vaporizer and detector temperatures were 250 ℃. The column box temperature program was as follows: the mixture is kept at 80 ℃ for 2 minutes, and then heated to 160 ℃ at a heating rate of 20 ℃/min, and kept for 2 minutes. The product was analyzed by gas chromatography and the yield of benzaldehyde was 90%.
Example 3
(1) Catalyst preparation
6g of melamine are calcined at 600 ℃ for 2h in nitrogen to give g-C 3 N 4 -a N material; 2g of g-C 3 N 4 Roasting the material-A in air at 550 ℃ for 2h to obtain eg-C 3 N 4 -a NA material. 0.2 part by mass of eg-C 3 N 4 -NA is added in 20 parts by mass of water, and is dispersed uniformly in water by ultrasonic and stirring. Then, PdCl was added dropwise to the above liquid under stirring 2 (control Pd to be eg-C) 3 N 4 The mass percentage of (b) is 1%). Adding excessive NaBH into the mixed solution 4 Solution (excess means NaBH 4 Can convert PdCl into 2 All reduced to Pd). And filtering the mixed solution, washing the mixed solution for many times by using distilled water, and drying the mixed solution to obtain the catalyst.
(2) Catalytic reaction
A reaction vessel such as a flask with a condensing reflux was charged with 30g of a catalyst and 4mL of benzyl alcohol, and reacted at a reaction temperature of 95 ℃ for 6 hours while passing oxygen (flow rate: 40 mL/min).
(3) Catalyst and product separation
After the catalytic reaction was completed, the reactor was rapidly cooled to room temperature. And slowly opening an air valve to exhaust the air in the air valve. Taking out the mixture of the reaction liquid and the catalyst in the reactor, and centrifuging or filtering to separate the catalyst and the reaction liquid. The isolated catalyst was washed with 20mL of ethanol for 30 minutes and then filtered. After repeating the above step for 3 times, the catalyst obtained by filtration was placed in a forced air oven and heated at 100 ℃ for 4 hours to obtain a recovered catalyst.
(4) Product analysis
The gas chromatography uses nitrogen as carrier gas, and is equipped with FFAP type capillary chromatographic column with column length of 30m and hydrogen ion flame detector. The vaporizer and detector temperatures were 250 ℃. The column box temperature program was as follows: the mixture is kept at 80 ℃ for 2 minutes, and then heated to 160 ℃ at a heating rate of 20 ℃/min, and kept for 2 minutes. The product is analyzed by gas chromatography, and the yield of the benzaldehyde is 80%.
Example 4
(1) Catalyst preparation
6g of dicyanodiamine are calcined for 3h at 550 ℃ in nitrogen to obtain g-C 3 N 4 -a N material; 2g of g-C 3 N 4 Roasting the-N material at 550 ℃ for 3h in nitrogen to obtain eg-C 3 N 4 -an NN material. 0.2 part by mass of eg-C 3 N 4 -NN was added to 20 parts by mass of water, and uniformly dispersed in the water by ultrasonic and stirring. Then, PdCl was added dropwise to the above liquid under stirring 2 (control Pd to be eg-C) 3 N 4 The mass percentage of (b) is 4%). Adding excessive NaBH into the mixed solution 4 Solution (excess means NaBH 4 Can convert PdCl into 2 All reduced to Pd). And filtering the mixed solution, washing the mixed solution for many times by using distilled water, and drying the mixed solution to obtain the catalyst.
(2) Catalytic reaction
A reaction vessel such as a flask equipped with a condensing reflux was charged with 30g of a catalyst and 4mL of benzyl alcohol, and reacted at a reaction temperature of 90 ℃ for 8 hours while passing oxygen (flow rate: 15 mL/min).
(3) Catalyst and product separation
After the catalytic reaction was completed, the reactor was rapidly cooled to room temperature. And slowly opening an air valve to exhaust the air in the air valve. Taking out the mixture of the reaction liquid and the catalyst in the reactor, and centrifuging or filtering to separate the catalyst and the reaction liquid. The isolated catalyst was washed with 20mL of ethanol for 30 minutes and then filtered. After repeating the above step for 3 times, the catalyst obtained by filtration was placed in a forced air oven and heated at 100 ℃ for 4 hours to obtain a recovered catalyst.
(4) Product analysis
The gas chromatography uses nitrogen as carrier gas, and is equipped with FFAP type capillary chromatographic column with column length of 30m and hydrogen ion flame detector. The vaporizer and detector temperatures were 250 ℃. The column box temperature program was as follows: the mixture is kept at 80 ℃ for 2 minutes, and then heated to 160 ℃ at a heating rate of 20 ℃/min, and kept for 2 minutes. The product was analyzed by gas chromatography and the yield of benzaldehyde was 88%.
Example 5
(1) Catalyst preparation
6g of dicyanodiamine is roasted in air at 550 ℃ for 4h to obtain g-C 3 N 4 -a material; 2g of g-C 3 N 4 -N material was calcined at 500 ℃ for 3h in nitrogen to get eg-C 3 N 4 -AN material. 0.2 part by mass of eg-C 3 N 4 -AN is added to 20 parts by mass of water, and is uniformly dispersed in the water by ultrasonic and stirring. Then, PdCl was added dropwise to the above liquid under stirring 2 (control Pd to be eg-C) 3 N 4 The mass percentage of (b) is 2.5%). Adding excessive NaBH into the mixed solution 4 Solution (excess means NaBH 4 Can convert PdCl into 2 All reduced to Pd). And filtering the mixed solution, washing the mixed solution for many times by using distilled water, and drying the mixed solution to obtain the catalyst.
(2) Catalytic reaction
A reaction vessel such as a flask with a condensing reflux was charged with 30g of a catalyst and 4mL of benzyl alcohol, and reacted at a reaction temperature of 95 ℃ for 5 hours while passing oxygen (flow rate: 20 mL/min).
(3) Catalyst and product separation
After the catalytic reaction was completed, the reactor was rapidly cooled to room temperature. And slowly opening an air valve to exhaust the air in the air valve. Taking out the mixture of the reaction liquid and the catalyst in the reactor, and centrifuging or filtering to separate the catalyst and the reaction liquid. The isolated catalyst was washed with 20mL of ethanol for 30 minutes and then filtered. After repeating the above step for 3 times, the catalyst obtained by filtration was placed in a forced air oven and heated at 100 ℃ for 4 hours to obtain a recovered catalyst.
(4) Product analysis
The gas chromatography uses nitrogen as carrier gas, and is equipped with FFAP type capillary chromatographic column with column length of 30m and hydrogen ion flame detector. The vaporizer and detector temperatures were both 250 ℃. The column box temperature program was as follows: the mixture is kept at 80 ℃ for 2 minutes, and then heated to 160 ℃ at a heating rate of 20 ℃/min, and kept for 2 minutes. The product was analyzed by gas chromatography and the yield of benzaldehyde was 95%.
Example 6
(1) Catalyst preparation
6g of dicyanodiamine is roasted in the air for 6 hours at 500 ℃ to obtain g-C 3 N 4 -a material; 2g of g-C 3 N 4 Calcining the material-A in nitrogen at 550 ℃ for 2h to obtain eg-C 3 N 4 -AN material. 0.2 part by mass of eg-C 3 N 4 -AN is added in 20 parts by mass of water, and is dispersed uniformly in water by ultrasonic and stirring. Then, PdCl was added dropwise to the above liquid under stirring 2 (control Pd to be eg-C) 3 N 4 2.5% by mass). Adding excessive NaBH into the mixed solution 4 Solution (excess means NaBH 4 Can convert PdCl into 2 All reduced to Pd). And filtering the mixed solution, washing the mixed solution for many times by using distilled water, and drying the mixed solution to obtain the catalyst.
(2) Catalytic reaction
A reaction vessel such as a flask equipped with a condensing reflux was charged with 30g of a catalyst and 4mL of benzyl alcohol, and reacted at a reaction temperature of 90 ℃ for 6 hours while passing oxygen (flow rate: 25 mL/min).
(3) Catalyst and product separation
After the catalytic reaction was completed, the reactor was rapidly cooled to room temperature. And slowly opening an air valve to exhaust the air in the air valve. Taking out the mixture of the reaction liquid and the catalyst in the reactor, and centrifuging or filtering to separate the catalyst and the reaction liquid. The isolated catalyst was washed with 20mL of ethanol for 30 minutes and then filtered. After repeating the above step for 3 times, the catalyst obtained by filtration was placed in a forced air oven and heated at 100 ℃ for 4 hours to obtain a recovered catalyst.
(4) Product analysis
The gas chromatography uses nitrogen as carrier gas, and is equipped with FFAP type capillary chromatographic column with column length of 30m and hydrogen ion flame detector. The vaporizer and detector temperatures were 250 ℃. The column box temperature program was as follows: the mixture is kept at 80 ℃ for 2 minutes, and then heated to 160 ℃ at a heating rate of 20 ℃/min, and kept for 2 minutes. The product was analyzed by gas chromatography, and the yield of benzaldehyde was 92%.
Table 1 shows 2.5Pd/eg-C of example 5 3 N 4 -reuse of AN catalyst.
TABLE 1 2.5Pd/eg-C from example 5 3 N 4 Reuse of AN catalyst
Number of repeated use Benzaldehyde yield (%)
0 95
1 94
2 94
3 93
4 94
5 94
Catalyst support of the invention (eg-C) 3 N 4 ) Is obtained by roasting a precursor in two steps. For comparison, g-C obtained by a one-step calcination 3 N 4 The preparation procedure and catalytic performance of Pd supported on the carrier were as follows.
Comparative example 1
(1) Catalyst preparation
6g of dicyanodiamine is roasted in air at 550 ℃ for 4h to obtain g-C 3 N 4 -a material. 0.2 part by mass of eg-C 3 N 4 The compound (A) is added to 20 parts by mass of water, and is uniformly dispersed in the water by ultrasonic and stirring. Then, PdCl was added dropwise to the above liquid under stirring 2 (control Pd to be eg-C) 3 N 4 2.5% by mass). Adding excessive NaBH into the mixed solution 4 Solution (excess means NaBH 4 Can convert PdCl into 2 All reduced to Pd). And filtering the mixed solution, washing the mixed solution for many times by using distilled water, and drying the mixed solution to obtain the catalyst.
(2) Catalytic reaction
A reaction vessel such as a flask with a condensing reflux was charged with 30g of a catalyst and 4mL of benzyl alcohol, and reacted at a reaction temperature of 95 ℃ for 5 hours while passing oxygen (flow rate: 20 mL/min).
(3) Catalyst and product separation
After the catalytic reaction was completed, the reactor was rapidly cooled to room temperature. And slowly opening an air valve to exhaust the air in the air valve. Taking out the mixture of the reaction liquid and the catalyst in the reactor, and centrifuging or filtering to separate the catalyst and the reaction liquid. The isolated catalyst was washed with 20mL of ethanol for 30 minutes and then filtered. After repeating the above step for 3 times, the catalyst obtained by filtration was placed in a forced air oven and heated at 100 ℃ for 4 hours to obtain a recovered catalyst.
(4) Product analysis
The gas chromatography uses nitrogen as carrier gas, and is equipped with FFAP type capillary chromatographic column with column length of 30m and hydrogen ion flame detector. The vaporizer and detector temperatures were 250 ℃. The column box temperature program was as follows: the mixture is kept at 80 ℃ for 2 minutes, and then heated to 160 ℃ at a heating rate of 20 ℃/min, and kept for 2 minutes. The product was analyzed by gas chromatography and the yield of benzaldehyde was 25%.
Comparative example 2
(1) Catalyst preparation
6g of dicyanodiamine are calcined at 550 ℃ for 4h in nitrogen to obtain g-C 3 N 4 -N material. 0.2 part by mass of eg-C 3 N 4 -N is added to 20 parts by mass of water, and is uniformly dispersed in the water by ultrasonic and stirring. Then, PdCl was added dropwise to the above liquid under stirring 2 (control Pd to be eg-C) 3 N 4 The mass percentage of (b) is 2.5%). Adding excessive NaBH into the mixed solution 4 Solution (excess means NaBH 4 Can convert PdCl into 2 All reduced to Pd). And filtering the mixed solution, washing the mixed solution for many times by using distilled water, and drying the mixed solution to obtain the catalyst.
(2) Catalytic reaction
A reaction vessel such as a flask with a condensing reflux was charged with 30g of a catalyst and 4mL of benzyl alcohol, and reacted at a reaction temperature of 95 ℃ for 5 hours while passing oxygen (flow rate: 20 mL/min).
(3) Catalyst and product separation
After the catalytic reaction was completed, the reactor was rapidly cooled to room temperature. And slowly opening an air valve to exhaust the air in the air valve. Taking out the mixture of the reaction liquid and the catalyst in the reactor, and centrifuging or filtering to separate the catalyst and the reaction liquid. The isolated catalyst was washed with 20mL of ethanol for 30 minutes and then filtered. After repeating the above step for 3 times, the catalyst obtained by filtration was placed in a forced air oven and heated at 100 ℃ for 4 hours to obtain a recovered catalyst.
(4) Product analysis
The gas chromatography uses nitrogen as carrier gas, and is equipped with FFAP type capillary chromatographic column with column length of 30m and hydrogen ion flame detector. The vaporizer and detector temperatures were 250 ℃. The column box temperature program was as follows: the mixture is kept at 80 ℃ for 2 minutes, and then heated to 160 ℃ at a heating rate of 20 ℃/min, and kept for 2 minutes. The product was analyzed by gas chromatography and the yield of benzaldehyde was 34%.
As can be seen by comparing the above comparative examples and examples: Pd/eg-C prepared by one-step roasting 3 N 4 The activity of the catalyst is obviously lower than that of Pd/eg-C prepared by two-step roasting in the example 3 N 4 A catalyst.
In light of the foregoing description of the preferred embodiment of the present invention, many modifications and variations will be apparent to those skilled in the art without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.

Claims (6)

1. A preparation method of a heterogeneous catalyst for selective oxidation of benzyl alcohol under the condition of no solvent oxygen is characterized by comprising the following steps:
(1) graphite phase carbon nitride (g-C) 3 N 4 ) Preparation of the material: roasting a certain amount of cyanamide, dicyanodiamine or melamine precursor in nitrogen or air atmosphere at a certain temperature for a period of time to obtain g-C 3 N 4 A material;
(2) exfoliated graphite phase carbon nitride (eg-C) 3 N 4 ) Preparation of the material: a certain amount of g-C 3 N 4 The material is roasted in nitrogen or air atmosphere at a certain temperature for a period of time to obtain eg-C 3 N 4 A material;
(3) preparation of supported Pd heterogeneous catalyst: 0.2 part by mass of eg-C 3 N 4 Adding 20 parts by mass ofSubjecting to ultrasonic treatment and stirring in water to obtain eg-C 3 N 4 Uniformly dispersing in water; then, PdCl was added dropwise to the above liquid under stirring 2 Wherein Pd comprises eg-C 3 N 4 The mass percentage of the components is 1-4 percent; adding excessive NaBH into the mixed solution 4 Solution, reacting NaBH 4 PdCl 2 All are reduced to Pd; filtering the obtained mixed solution, washing the mixed solution for many times by distilled water, and drying the mixed solution to obtain the heterogeneous catalyst which is recorded as Pd/eg-C 3 N 4 。
2. The method as claimed in claim 1, wherein the calcination temperature in step (1) is 500-600 ℃.
3. The method for preparing the heterogeneous catalyst for the selective oxidation of benzyl alcohol under the solvent-free oxygen condition as claimed in claim 1, wherein the calcination time in step (1) is 2-8 hours.
4. The method as claimed in claim 1, wherein the calcination temperature in step (2) is 450-550 ℃.
5. The method for preparing the heterogeneous catalyst for the selective oxidation of benzyl alcohol under the solvent-free oxygen condition as claimed in claim 1, wherein the calcination time in the step (2) is 2-4 hours.
6. The use of the heterogeneous catalyst for the selective oxidation of benzyl alcohol under the condition of no solvent oxygen as claimed in claim 1, wherein the heterogeneous catalyst is used in the selective oxidation of benzyl alcohol by the following steps: adding benzyl alcohol and Pd/eg-C into a flask reaction vessel with condensation reflux 3 N 4 Introducing oxygen into the catalyst at the flow rate of 10-40mL/min, reacting at the reaction temperature of 85-100 ℃ for 1-10 hours, and centrifuging or filtering to separate the catalyst and the reaction liquid.
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5995238A (en) * 1982-11-19 1984-06-01 Mitsubishi Petrochem Co Ltd Preparation of phenylacetic acid derivative
CN108772087A (en) * 2018-05-17 2018-11-09 常州大学 A kind of Supported Pd-Catalyst and preparation method thereof for benzyl alcohol oxidation synthesizing benzaldehyde under solvent-free system
CN110479253A (en) * 2019-09-12 2019-11-22 大连理工大学 A kind of Nano diamond-carried palladium catalyst and its preparation method and application for benzyl alcohol producing benzaldehyde
CN111185220A (en) * 2020-03-20 2020-05-22 中国科学院长春应用化学研究所 Carbon nitride supported Pd-based catalyst, and preparation method and application thereof
CN113042089A (en) * 2021-03-31 2021-06-29 常州大学 Supported nano palladium catalyst for synthesizing benzaldehyde from oxygen and benzyl alcohol and preparation method thereof

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5995238A (en) * 1982-11-19 1984-06-01 Mitsubishi Petrochem Co Ltd Preparation of phenylacetic acid derivative
CN108772087A (en) * 2018-05-17 2018-11-09 常州大学 A kind of Supported Pd-Catalyst and preparation method thereof for benzyl alcohol oxidation synthesizing benzaldehyde under solvent-free system
CN110479253A (en) * 2019-09-12 2019-11-22 大连理工大学 A kind of Nano diamond-carried palladium catalyst and its preparation method and application for benzyl alcohol producing benzaldehyde
CN111185220A (en) * 2020-03-20 2020-05-22 中国科学院长春应用化学研究所 Carbon nitride supported Pd-based catalyst, and preparation method and application thereof
CN113042089A (en) * 2021-03-31 2021-06-29 常州大学 Supported nano palladium catalyst for synthesizing benzaldehyde from oxygen and benzyl alcohol and preparation method thereof

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
XIN-TONG YI ET AL.: "The solvent-free and aerobic oxidation of benzyl alcohol catalyzed by Pd supported on carbon nitride/CeO2 composites", 《NEW J. CHEM.》, vol. 46, pages 7108 - 7117 *

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