Method for synthesizing aminobenzaldehyde by using waste heat and nano thermoelectric composite catalyst to catalyze oxidation of aminobenzyl alcohol

Abstract

The application belongs to the field of machine conversion catalysis, and discloses a method for synthesizing aminobenzaldehyde by oxidizing aminobenzyl alcohol by using waste heat and a nano thermoelectric composite catalyst. The nano thermoelectric composite catalyst takes Bi2Te3 nanosheet thermoelectric material as a matrix, and a coating layer is a metal organic framework Fe-MOF loaded with iron. The nano thermoelectric composite catalyst utilizes the temperature difference caused by waste heat to perform a thermoelectric catalytic Fenton reaction, and the steps are as follows: the nano thermoelectric composite catalyst is sprayed and adhered to the outer wall of a heat source, a cooling jacket circulating device is fixed outside the heat source shell, an aminobenzyl alcohol aqueous solution is added into the cooling jacket as a cooling liquid, a cooling pipeline is connected into the cooling jacket circulating system, the aminobenzyl alcohol aqueous solution is passed into O2 before the reaction starts, and then the cooling system is started to cool the heat source. The temperature difference is kept at 45-50 DEG C, the temperature difference effect is kept for 150 min, the conversion rate is 57%, and the purity is 99%. The method improves the utilization of waste heat, is green and environment-friendly, and has a good application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to a green energy-saving synthesis strategy for converting aminobenzyl alcohol into aminobenzaldehyde, a high-value pharmaceutical intermediate, using industrial and domestic waste heat and thermoelectric effect. Specifically, it relates to the catalytic effect of a metal-organic framework (Fe-MOF) thermoelectric nanosheet composite material loaded with iron, and particularly to a green energy-saving new method for efficiently oxidizing aminobenzyl alcohol into aminobenzaldehyde through a thermoelectric catalytic Fenton reaction using the temperature difference caused by waste heat. BACKGROUND

[0002] Aminobenzaldehyde is a high-value organic compound with the chemical formula C7H7NO. It is a yellow crystalline solid with a special aromatic odor and is often used as an important raw material for dyes, perfumes, and pharmaceutical production. In the pharmaceutical field, aminobenzaldehyde can form compounds with pharmacological activity by reacting with other compounds. It is a key intermediate for the synthesis of antibiotics, anticancer drugs, and other products.

[0003] The conventional preparation method of aminobenzaldehyde has the problems of high energy consumption and the use of toxic heavy metal strong oxidants, which causes serious environmental pollution and does not meet the principles of green chemistry and the "double carbon" goal of today's society. The presence of heavy metal strong oxidants also causes excessive oxidation of the target product. Therefore, the traditional synthesis route has the disadvantages of low purity, low efficiency, and high energy consumption. Therefore, it is of great market value to develop an environmentally friendly and efficient, low-energy, and high-purity product catalytic reaction new strategy.

[0004] Thermoelectric materials can cause directional migration of electrons or holes from the hot end to the cold end under the action of a certain temperature difference, and then a large number of electric charges are enriched on the surface of the material to participate in surface reactions and generate active free radical species. The use of waste heat and residual heat can easily generate a temperature difference between the two ends of the thermoelectric material, realize the generation of active substances, and then start the catalytic conversion reaction. Therefore, this idea not only utilizes the waste heat released into the environment, but also provides a green and environmentally friendly new way for industrial production of aromatic aldehydes. The key to this technology is how to design efficient thermoelectric catalysts and how to effectively utilize waste heat.

[0005] So far, there has been no report on the use of thermoelectric materials to catalyze the oxidation of aminobenzyl alcohol to synthesize aminobenzaldehyde. SUMMARY

[0006] The main purpose of the present application is to provide a green energy-saving new method for catalytic synthesis of aminobenzaldehyde pharmaceutical intermediates using waste heat. The thermoelectric catalyst composite material contacts the heating area, a temperature difference is generated on the front and back of the thermoelectric material, causing the thermoelectric effect of the material, and using this as the driving force for the catalytic reaction to oxidize aminobenzyl alcohol to obtain aminobenzaldehyde pharmaceutical intermediates.

[0007] The application innovatively proposes to design Fe-MOF (Fe-UIO-66-NH2)-thermoelectric material composite as a catalyst, which shows good organic matter catalytic oxidation performance under a continuous temperature difference. This is due to the fact that the Bi2Te3 nanosheet thermoelectric material has good room-temperature thermoelectric performance, such as a high Seebeck coefficient and good electrical conductivity, and can generate stable thermoelectric effects under the action of a temperature difference, so that a large number of electrons and holes are accumulated at both ends of the material. Meanwhile, the Fe-MOF layer on the surface of the thermoelectric material can promote the surface catalytic conversion reaction.

[0008] By reasonably designing a reaction system, using the natural heat dissipation process of heat sources such as high-temperature industrial pipelines and air conditioner outdoor units, coating the catalyst material on the outer shell of high-temperature objects, and assisting with a cooling jacket circulating device, the waste heat released by the pipelines and fans can be fully utilized to transfer heat to the catalyst material, start the thermoelectric effect of the catalyst, and realize the continuous conversion reaction of aminobenzyl alcohol while cooling.

[0009] The application is realized by the following technical scheme:

[0010] The application discloses a nano thermoelectric composite catalyst, which comprises a nanosheet thermoelectric material as a matrix and Fe-MOF material compounded on the surface of the thermoelectric material; wherein the nanosheet thermoelectric material is Bi2Te3; and the Fe-MOF material is Fe-UiO-66-NH2.

[0011] The nano thermoelectric composite catalyst can make electrons and holes migrate from the hot end to the cold end under the action of a temperature difference, a large number of electric charges are accumulated at the cold end, and H2O2 and other oxidizing substances are generated in an O2-containing environment; Fe 2+ Fenton reaction occurs with H2O2 to generate a large number of high-activity species, and the surface catalytic conversion reaction is improved, so that efficient organic matter catalytic conversion is realized.

[0012] The application further discloses a preparation method of the nano thermoelectric composite catalyst, which comprises the following steps:

[0013] Firstly, inert gas is introduced into N,N-dimethylformamide (DMF) for a certain time, then FeSO4·7H2O, ZrCl4 and the nanosheet thermoelectric material are sequentially added, the system is heated to a first preset temperature, and then kept for a certain time; then 2-amino terephthalic acid is added, the system is continuously heated to a second preset temperature, and then kept for a certain time; the obtained powder is cleaned with DMF, centrifuged, and vacuum dried to obtain the nano thermoelectric composite catalyst of the Fe-MOF-coated nanosheet thermoelectric material, which is recorded as Bi2Te3@Fe-MOF.

[0014] The amount ratio of FeSO4·7H2O, ZrCl4 and nanosheet thermoelectric material is 46mg: 46.6mg: 100mg;

[0015] The molar ratio of 2-amino terephthalic acid and ZrCl4 is 1:1.

[0016] The first preset temperature is 60℃, and the holding time is 30min.

[0017] The second preset temperature is 120℃, and the holding time is 60min.

[0018] The nanometer thermoelectric composite catalyst is used for catalyzing and oxidizing aminobenzyl alcohol into aminobenzaldehyde.

[0019] Further, the application provides a method for catalyzing and oxidizing aminobenzyl alcohol into aminobenzaldehyde by using waste heat and the nanometer thermoelectric composite catalyst. The specific operation is as follows: the prepared nanometer thermoelectric composite catalyst is mixed with carbon-containing glue material, the mixed material is coated on the outer shell of a high-temperature pipeline by using a spraying technology, then a cooling jacket is fixed outside the high-temperature pipeline, 500-1000mL of aminobenzyl alcohol aqueous solution with a concentration of 0.05-0.07g / L is added into the cooling jacket as a cooling liquid, the cooling jacket is connected into a cooling circulation system through a pipeline, and the aminobenzyl alcohol aqueous solution is bubbled with O2 for 30-60min before the reaction starts. The temperature of the cooling circulation system is set to 10℃-room temperature, then the cooling circulation system is started to cool the aminobenzyl alcohol aqueous solution, and after the temperature difference between the cold end and the hot end is stable and greater than 20℃, the timing is started, and the sample is taken every 30min for detection.

[0020] The working principle of the application is as follows:

[0021] In the prepared nanometer thermoelectric composite material catalyst of Fe-MOF coated Bi2Te3, the nanosheet thermoelectric material Bi2Te3 substrate has excellent thermoelectric performance, the Fe-MOF coating layer has a high specific surface area, and contains a large amount of Fe 2+ Under the action of temperature difference, a thermoelectric effect is generated, a large amount of electric charges are accumulated at the cold end and the hot end of the nanosheet thermoelectric material respectively, H2O2 is generated, and the surrounding Fe 2+ Fenton reaction occurs to generate a large amount of high-activity species, and the catalytic oxidation reaction of aminobenzyl alcohol is efficiently improved.

[0022] The beneficial technical effects of the application are as follows:

[0023] (1) Compared with other thermoelectric materials, Bi2Te3 has a higher Seebeck coefficient at room temperature, can generate obvious thermoelectric effect at a lower temperature difference, and can generate more electric charges at the cold end and the hot end; Fe-MOF has a larger specific surface area, and can provide more reaction active sites for the catalytic reaction.

[0024] (2) Compared with the traditional synthesis method of p-aminobenzaldehyde, the waste heat is utilized to provide driving force for the reaction, the waste heat released into the environment is utilized, the utilization rate of energy is improved, the environment is not polluted, it is a new green energy-saving method with low energy consumption and high conversion rate. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 Figure is a schematic diagram of the preparation method of the Fe-MOF coated Bi2Te3 nano thermoelectric composite catalyst.

[0026] Figure 2 (a) is a transmission electron microscope image of Bi2Te3 nano material, Figure 2 (b) is a transmission electron microscope image of the Fe-MOF coated Bi2Te3 nano thermoelectric composite catalyst.

[0027] Figure 3 Figure is an XRD pattern of the Bi2Te3@Fe-MOF nano thermoelectric composite catalyst and a standard pattern.

[0028] Figure 4 Figure is a schematic diagram of the process of catalysis by cooling the high-temperature industrial pipeline.

[0029] Figure 5 Figure is a catalytic oxidation efficiency diagram of the Fe-MOF coated Bi2Te3 nano thermoelectric composite catalyst for aminobenzyl alcohol.

[0030] Figure 6 Figure is a comparison diagram of the catalytic oxidation efficiency of the Fe-MOF coated Bi2Te3 nano thermoelectric composite catalyst for aminobenzyl alcohol under different temperature differences. DETAILED DESCRIPTION

[0031] The present application encompasses any alternatives, modifications, equivalent methods and solutions made within the essence and scope of the present application as defined by the claims. Further, in order to make the public have a better understanding of the present application, some specific details are described in detail in the following detailed description of the present application. The present application can also be fully understood without the description of these details by those skilled in the art.

[0032] In one aspect, the embodiment of the present application provides a nano thermoelectric composite catalyst, which comprises a nanosheet thermoelectric material as a matrix, and a Fe-MOF material coated on the surface of the thermoelectric material.

[0033] Among them, the Fe-MOF is selected from Fe-UiO-66-NH2. Figure 1 The Fe-MOF coated Bi2Te3 nano thermoelectric composite catalyst is prepared by a wet chemical method:

[0034] Put 70 mL of N,N-dimethylformamide (DMF) into a three-necked flask, remove oxygen in the solution by inert gas for 30 min, add 46 mg of FeSO4·7H2O into the three-necked flask, after dissolution, sequentially add 46.6 mg of ZrCl4 and 100 mg of Bi2Te3 nanosheet powder, heat to 60℃, and keep for 30 min, then add 36 mg of 2-amino terephthalic acid into the solution, stir for 2 min, heat to 120℃, and keep for 60 min, cool, centrifugal, wash with DMF, centrifugal, and vacuum dry to obtain a Fe-MOF coated Bi2Te3 nanometer thermoelectric composite catalyst.

[0035] In another aspect, the present application provides a new green energy-saving method for catalytic oxidation of aminobenzyl alcohol to aminobenzaldehyde by using waste heat and a nanometer thermoelectric composite catalyst.

[0036] Mix 680 mg of thermoelectric catalytic material with carbon-containing glue material, coat the mixed catalytic material on the outer shell of a high-temperature pipeline by using a spraying technique, fix a cooling jacket outside the high-temperature pipeline, then pass 500-1000 mL of an aminobenzyl alcohol aqueous solution with a concentration of 0.05-0.07 g / L into the cooling jacket as a cooling liquid, connect the cooling pipeline into a cooling circulation system, and pass the aminobenzyl alcohol aqueous solution into the O2 bubble for about 30-60 min before starting the reaction. Start the cooling circulation system to cool the aminobenzyl alcohol aqueous solution, and take samples for detection every 30 min.

[0037] Optionally, the temperature difference between the cold end and the hot end is greater than 20℃, and the temperature of the cooling circulation system is set to 10℃-room temperature.

[0038] The actual effect of the present application is proved by experiments.

[0039] The present application provides an application of the above-mentioned nanometer thermoelectric composite catalyst in catalytic oxidation of aminobenzyl alcohol. The thermoelectric effect is generated by temperature difference, and the Fenton reaction cooperates with the thermoelectric effect to initiate the catalytic oxidation reaction of aminobenzyl alcohol.

[0040] Example 1

[0041] Put 70 mL of DMF into a three-necked flask, remove oxygen in the solution by N2 for 30 min, add 46 mg of FeSO4·7H2O into the three-necked flask, wait for dissolution, then sequentially add 46.6 mg of ZrCl4 and 100 mg of Bi2Te3 into the three-necked flask, gradually heat the reaction device to 60℃, and keep for 30 min, then add 36 mg of 2-amino terephthalic acid into the solution, stir for 2 min, heat to 120℃, and keep for 60 min, cool, centrifugal, wash with DMF, centrifugal, and vacuum dry to obtain a nanometer thermoelectric composite catalyst with core-shell structure.

[0042] Take 680 mg of the above-synthesized nano-thermoelectric composite catalyst and mix with carbon-containing glue material, coat the mixed catalyst material on the high-temperature pipeline shell. Fix the cooling jacket circulating device outside the high-temperature industrial pipeline, then add 300-800 ml of 0.05-0.07 g / L concentration of aminobenzyl alcohol aqueous solution into the cooling jacket, connect the cooling pipeline into the cooling jacket circulating system, and pass the aminobenzyl alcohol aqueous solution into O2 bubbling for 30-60 min before the reaction starts. After the heat source temperature and the cooling circulating system temperature are stabilized, start the cooling system to cool the heat source, and take samples every 30 min for detection. The temperature difference is maintained at 45-50℃, and the temperature difference effect is maintained for 150 min, the conversion rate is 23%, and the purity is 99%.

[0043] Example 2

[0044] Take the nano-thermoelectric composite catalyst obtained in Example 1 and perform aminobenzyl alcohol catalytic oxidation synthesis of p-aminobenzaldehyde experiment, the temperature difference is maintained at 35-40℃, and the temperature difference effect is maintained for 150 min, the conversion rate is 21%, and the purity is 99%.

[0045] Example 3

[0046] Take the nano-thermoelectric composite catalyst obtained in Example 1 and perform aminobenzyl alcohol catalytic oxidation synthesis of p-aminobenzaldehyde experiment, the temperature difference is maintained at 55-60℃, and the temperature difference effect is maintained for 150 min, the conversion rate is 57%, and the purity is 99%.

[0047] Figure 1 The preparation method flowchart of the Fe-MOF-coated Bi2Te3 nano-thermoelectric composite catalyst Bi2Te3@Fe-MOF.

[0048] Figure 2 (a) is a transmission electron microscope image of Bi2Te3 nanomaterials, Figure 2 (b) is a transmission electron microscope image of Bi2Te3@Fe-MOF nano-thermoelectric composite catalyst. It can be seen from the figure that Fe-MOF has completely coated the surface of Bi2Te3 nanomaterials. The size is: 200 nm long and 20 nm thick, in the shape of a hexagon.

[0049] Figure 3 The XRD pattern of the Bi2Te3@Fe-MOF nano-thermoelectric composite catalyst and the standard pattern.

[0050] Figure 4The schematic diagram of the catalytic process using the waste heat emitted by high-temperature industrial pipelines. First, the catalyst is sprayed on the outer shell of the heat dissipation pipeline, then the cooling jacket is assembled on the catalyst-coated pipe and sealed, and finally the cooling system is set up and opened to start circulation, and the thermoelectric catalytic organic synthesis is carried out.

[0051] Figure 5 The efficiency comparison chart of Bi2Te3@Fe-MOF nano thermoelectric composite catalyst in catalytic oxidation of aminobenzyl alcohol under a temperature difference of 45-50℃. As can be seen from the chart, the Fe-MOF coated Bi2Te3 nano thermoelectric composite catalyst has obvious effect on the catalytic oxidation synthesis of p-aminobenzaldehyde.

[0052] Figure 6 The efficiency chart of Bi2Te3@Fe-MOF nano thermoelectric composite catalyst in catalytic oxidation of aminobenzyl alcohol to synthesize aminobenzaldehyde under different temperature differences. As can be seen from the chart, the catalytic efficiency is closely related to the temperature difference, and the efficiency is the highest when the temperature difference is 45-50℃.

Claims

1. A method for synthesizing aminobenzaldehyde by using waste heat and a nano thermoelectric composite catalyst to catalyze oxidation of aminobenzyl alcohol, characterized in that, The steps are: Mix the nano thermoelectric composite catalyst with carbon-containing glue material, coat the mixed material on the high-temperature pipeline shell by spraying technology, fix the cooling jacket outside the high-temperature pipeline shell, then add the aqueous solution of aminobenzyl alcohol in the cooling jacket as the cooling liquid, connect the cooling jacket into the cooling circulation system through the pipeline, bubble the aqueous solution of aminobenzyl alcohol with O2 before the reaction starts, set the temperature of the cooling circulation system to 10℃-room temperature, then start the cooling circulation system to cool the aqueous solution of aminobenzyl alcohol, and after the temperature difference between the cold and hot ends is stable and greater than 20℃, start timing; The nano thermoelectric composite catalyst comprises a nanosheet thermoelectric material as a matrix and a Fe-MOF material coated on the surface of the thermoelectric material. The nanosheet thermoelectric material is Bi2Te3, and the Fe-MOF material is Fe-UiO-66-NH2.

2. The method of claim 1, wherein, The volume of the aqueous solution of aminobenzyl alcohol is 500-1000mL, and the concentration is 0.05-0.07g / L.

3. The method of claim 1, wherein, The bubbling time of O2 is 30-60min.

4. The method of claim 1, wherein, The nano thermoelectric composite catalyst is prepared by the following steps: First, inert gas is introduced into N,N-dimethylformamide (DMF) for a certain period of time, then FeSO4·7H2O, ZrCl4 and nanosheet thermoelectric material are added in sequence, the system is heated to a first preset temperature and maintained for a certain period of time, then 2-amino terephthalic acid is added, the system is continuously heated to a second preset temperature and maintained for a certain period of time, the obtained powder is washed with DMF, centrifuged and vacuum dried to obtain a nano thermoelectric composite catalyst of Fe-MOF coated nanosheet thermoelectric material.

5. The method of claim 4, wherein, The amount ratio of FeSO4·7H2O, ZrCl4 and nanosheet thermoelectric material is 46mg:46.6mg:100mg.

6. The method of claim 4, wherein, The molar ratio of 2-amino terephthalic acid to ZrCl4 is 1:

1.

7. The method of claim 4, wherein, The first preset temperature is 60℃, and the holding time is 30min; the second preset temperature is 120℃, and the holding time is 60min.

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