Application of delta crystal form manganese dioxide in preparation of N-benzylidene benzylamine by catalyzing benzylamine

Abstract

The invention relates to an application of delta crystal form manganese dioxide in catalyzing benzylamine to prepare N-benzylidene benzylamine, and belongs to the technical field of catalyst preparation and application, the delta crystal form manganese dioxide is used as a catalyst, toluene is used as a solvent, and benzylamine is catalyzed in an oxygen atmosphere to carry out an oxidation self-coupling reaction to prepare N-benzylidene benzylamine. The maximum conversion rate of benzylamine reaches 99.9%, and the selectivity of N-benzylidene benzylamine reaches 98.0% or above. The delta crystal form manganese dioxide catalyst disclosed by the invention is simple in preparation method, low in production cost and high in selectivity, can be prepared on a large scale, is used for catalyzing aerobic oxidation self-coupling of benzylamine to prepare N-benzylidene benzylamine, can be recycled for four times, and has a wide industrialization prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of catalyst preparation, and specifically relates to a method for preparing benzylamine by catalyzing a δ-crystalline manganese dioxide. N -Application of benzalkonium chloride. Background Art

[0002] N -Benzylidenebenzylamine is a colorless liquid organic compound with an aromatic odor at room temperature. N -Benzylbutylamine is mainly used as an intermediate in organic synthesis. It has strong alkalinity and often exhibits electrophilicity in chemical reactions and can react with nucleophilic reagents. It can be chemically modified by reduction or rearrangement reactions, such as oxidation, substitution or addition. Because its molecules contain benzyl and amine groups, N -Benzalkonium chloride is also commonly used as a catalyst or ligand. N -Benzalkonium chloride can also be used as a starting material in organic synthesis, and organic molecules with different structures and properties can be synthesized by controlling the reaction conditions. Its reactivity and chemical diversity make it widely used in the fields of pharmacy, pesticides, fragrances and dyes.

[0003] Preparation by oxidative self-coupling of benzylamine N -benzylidenebenzylamine is one of the most effective methods. However, most of the reported protocols require oxidants that are harmful to humans and the environment, such as permanganate, chromate, and 2-iodoxybenzoic acid, which is very unfavorable from the perspective of green chemistry. Replacing these toxic and harmful oxidants with green oxidants such as air or O2 is an attractive and widely-attended research area. In the past decade, various heterogeneous catalysts have been applied to the self-coupling reaction of benzylamine, including noble metal-based catalysts such as Pt, Pd, Au, and Ru, and non-noble metal-based catalysts such as V, Cu, Co, and Mn, as well as other catalytic systems using MOFs, GO, and photocatalysts as catalysts. However, although some catalytic systems have obtained satisfactory N -benzylidenebenzylamine yield, but most of them either require complex catalysts, precious metals, toxic catalyst synthesis processes, harsh reaction conditions, light irradiation, excessively long reaction times, the addition of bases, or poor catalyst reusability, as well as poor selectivity due to the formation of by-products. Therefore, there has long been a need for an effective heterogeneous catalytic system for the aerobic oxidation of benzylamine to overcome and solve the above problems. Among the existing metal oxides, manganese oxide is inexpensive, non-toxic, and has efficient catalytic performance for many catalytic processes, such as the selective oxidation of various organic compounds, CO oxidation, and water decomposition reactions. Due to the rich active sites (Mn 3+), so it has excellent catalytic activity, and has excellent redox properties due to its multivalence, weaker metal-oxygen chemical bonds, rich lattice oxygen content and high oxygen mobility. In addition, among many metal oxides, manganese oxides have low preparation costs, high activity, and a variety of crystal structures. Manganese oxides with different crystal structures have different surface microstructures and chemical compositions, resulting in different catalytic properties. The δ-crystalline manganese dioxide has abundant acid-base active sites due to its unique two-dimensional layered structure. In addition, it also has abundant active sites (Mn 3 + ), weak metal-oxygen chemical bonds, rich lattice oxygen content and high oxygen mobility, and thus have excellent redox properties. N -Benzalkonylamine has high activity and can be prepared by aerobic oxidation of benzylamine via self-coupling N -The field of benzylidenebenzylamine has received extensive attention.

[0004] In summary, the catalytic aerobic oxidation of benzylamine was self-coupling to prepare N -benzylidenebenzylamine is an efficient and applicable method, so the development is simple, green, low-cost and capable of large-scale preparation of δ-MnO2, which is used to catalyze the aerobic oxidation self-coupling of benzylamine to prepare N -benzylidenebenzylamine, is of great significance. Summary of the invention

[0005] In view of the above problems existing in the existing catalytic aerobic oxidation self-coupling reaction of benzylamine, the object of the present invention is to provide a delta crystalline manganese dioxide for catalyzing the preparation of benzylamine N - Application in benzalkonium chloride, and provide a preparation method of the catalyst. The preparation process of the catalyst is simple, the price is low, the product yield is high, and it can be prepared in large quantities, and catalyze the aerobic oxidation self-coupling reaction of benzylamine. N -Benzalbenzylamine has high activity and selectivity and good economic and practical value.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions.

[0007] The purpose of the present invention is to provide a method for preparing benzylamine by catalyzing the production of benzylamine by using delta crystalline manganese dioxide. N - Application of benzalkonium chloride in the preparation of benzalkonium chloride, using delta crystal manganese dioxide as catalyst, toluene as solvent, catalyzing benzylamine to undergo oxidative self-coupling reaction in an oxygen atmosphere N -benzylidenebenzylamine, the reaction formula is as follows:

[0008] Preferably, the δ-crystalline manganese dioxide catalyst has a conversion rate of 35.1% to benzylamine under the reaction conditions of 0.1 MPa O2 pressure, 70 °C reaction temperature, and 0.25 h reaction time. The conversion rate of benzylamine can reach 99.9% after 9 h of reaction. N The selectivity of -benzylidenebenzylamine reached over 98.0%.

[0009] Preferably, the preparation steps of the delta crystalline manganese dioxide are as follows: (1) Preheat the potassium permanganate solution and the manganese sulfate solution to a temperature T, 80 ℃ ≤ T < 90 ℃ respectively; (2) Adding potassium permanganate solution and manganese sulfate solution into the reactor of the microfluidic reaction device at the same time, reacting at a constant temperature, the reaction temperature is 80 ℃ ≤ T < 90 ℃, and the reaction time is 1 h; (3) The product obtained by the reaction was allowed to stand for 24 hours, filtered and washed until the pH value was 7, and dried at a constant temperature of 80°C. After cooling to room temperature, the product was ground to obtain delta crystalline manganese dioxide.

[0010] In the above preparation method, the microfluidic reaction device uses a disclosed technical solution, such as the invention patent with authorization announcement number CN 114956188 B, a method for continuously preparing delta crystalline manganese dioxide by microfluidics, the microfluidic reaction device includes a first raw material tank, a second raw material tank, a Hastelloy pump, a stainless steel pump, a reactor and a product tank, the first raw material tank stores potassium permanganate solution, the second raw material tank stores manganese sulfate solution, the first raw material tank and the second raw material tank are both provided with a first temperature control device for preheating the solution at the bottom, the inlet and outlet of the Hastelloy pump are respectively connected to the first raw material tank and the reactor through an insulation pipe, the inlet and outlet of the stainless steel pump are respectively connected to the second raw material tank and the reactor through an insulation pipe, the bottom of the reactor is provided with a second temperature control device, and the discharge port of the reactor is connected to the product tank through a pipe.

[0011] It should be noted that by controlling the preheating temperature and the reaction temperature, manganese dioxide of different crystal forms can be obtained. When the reaction temperature T is controlled at 0 ℃ ≤ T < 80 ℃, the product generated by the reaction is α-type manganese dioxide; when the reaction temperature T is controlled at 80 ℃ ≤ T < 90 ℃, the product generated by the reaction is δ-type manganese dioxide; when the reaction temperature T is controlled at 90 ℃ ≤ T ≤ 150 ℃, the product generated by the reaction is γ-type manganese dioxide.

[0012] Preferably, in the step (1) of preparing the delta crystalline manganese dioxide, the feeding concentration c1 of the potassium permanganate solution is controlled to be 0 mol / L<c1≤1 mol / L.

[0013] Preferably, in the step (1) of preparing the delta crystalline manganese dioxide, the feeding concentration c2 of the manganese sulfate solution is controlled to be 0 mol / L<c2≤1 mol / L.

[0014] Preferably, in the step (2) of preparing the delta crystalline manganese dioxide, the feed flow rate Q1 of the potassium permanganate solution is controlled to be 60 g / min≤Q1≤80 g / min.

[0015] Preferably, in the step (2) of preparing the delta crystalline manganese dioxide, the feed flow rate Q2 of the manganese sulfate solution is controlled to be 70 g / min≤Q2≤120 g / min The δ-crystalline manganese dioxide prepared by the present invention has a unique two-dimensional layered structure, and its surface has not only abundant Lewis acid-base active sites, but also abundant active sites (Mn 3+ ), weaker metal-oxygen chemical bonds, rich lattice oxygen content and higher oxygen mobility, and thus have excellent redox properties. It has a better activation effect on the aerobic oxidation reaction of benzylamine, and has higher catalytic activity for the oxidation process of benzylamine. In addition, δ-type manganese dioxide has higher catalytic stability. While α-type manganese dioxide has a chain-like structure, γ-type manganese dioxide has a grain-like structure, with few active sites on its surface and relatively less catalytic activity. Therefore, δ-type manganese dioxide has better catalytic activity than other crystalline forms of manganese dioxide.

[0016] By adopting the above technology, compared with the prior art, the beneficial effects of the present invention are as follows: The delta crystal manganese dioxide of the present invention can be prepared in large quantities by adopting a microfluidic method, uses cheap raw materials, and has low production costs, so it can be industrialized.

[0017] The delta crystal manganese dioxide catalyst of the present invention has good catalytic properties for the aerobic oxidation self-coupling reaction of benzylamine. N -benzylidenebenzylamine performance; and under the reaction conditions of 0.1 MPa O2 pressure, 70 ℃ reaction temperature, 100 mg catalyst, 0.5 g benzylamine, 0.25 h reaction time and 20 mL toluene, the conversion rate of benzylamine by the δ-crystalline MnO2 catalyst reached 35.1%, and the conversion rate of benzylamine could reach 99.9% after 9 h reaction. N The selectivity of -benzylidenebenzylamine reaches over 98.0%, has the advantage of high yield, and can be recycled four times, with broad industrial prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The XRD pattern of the δ-MnO2 catalyst prepared in Example 1; Figure 2This is the XRD pattern of the α-MnO2 catalyst prepared in Example 6; Figure 3 This is the XRD pattern of the γ-MnO2 catalyst prepared in Example 7; Figure 4 TEM images of three different crystalline MnO2 catalysts; Figure 5 This is a process analysis diagram of the catalytic performance of the δ-MnO2 catalyst changing with time; Figure 6 This is the performance diagram of the δ-MnO2 catalyst stability experiment; Figure 7 Schematic diagram of the microfluidic reaction device.

[0019] In the figure: 1-first raw material tank; 2-second raw material tank; 3-Hastelloy pump; 4-stainless steel pump; 5-insulated pipe; 6-microfluidic reactor; 7-first temperature control device; 8-second temperature control device; 9-product tank. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further described below with specific embodiments, but the protection scope of the present invention is not limited thereto. Although the steps in the present invention are arranged with reference numbers, they are not used to limit the order of the steps. Unless the order of the steps is clearly stated or the execution of a certain step requires other steps as a basis, the relative order of the steps can be adjusted. Unless otherwise specified, the chemical reagents and materials in the present invention are purchased through market channels or synthesized from raw materials purchased through market channels.

[0021] In the embodiments of the present invention, products prepared under different temperature conditions, namely, delta-type, alpha-type and gamma-type manganese dioxide catalysts are used as examples to test the performance and parameters of the products and determine the best performance of the products.

[0022] Example 1: Preparation of δ-MnO2 1 mol / L potassium permanganate solution and 0.8 mol / L manganese sulfate solution were preheated to 85 °C respectively, and then the potassium permanganate solution at a feed rate of 60 g / min and the manganese sulfate solution at a feed rate of 100 g / min were simultaneously added to the reactor of the microfluidic reaction device for reaction to obtain δ-manganese dioxide.

[0023] The specific steps for preparing delta-manganese dioxide are as follows: Figure 7In the process flow, potassium permanganate solution and manganese sulfate solution are respectively placed in the first raw material tube tank 1 and the second raw material tank 2, and the potassium permanganate solution and the manganese sulfate solution are heated to a predetermined temperature by the first temperature control device 7. The heated potassium permanganate solution enters the reactor 6 through the Hastelloy pump 3 and the insulation pipe 5. At the same time, the heated manganese sulfate solution enters the reactor 6 through the insulation pipe 5 through the stainless steel pump 4. The two solutions are controlled to enter the reactor 6 at the same time for reaction. The temperature of the reactor 6 is adjusted and controlled by the second temperature control device 8. The manganese dioxide generated by the reaction is transported to the product tank 9 through the insulation pipe 5. The product in the product tank 9 is allowed to stand for 24 hours, and then filtered and washed to a pH value of 7, and then placed in a drying oven at 80°C for drying. After cooling to room temperature, it is ground to obtain a product of δ-MnO2.

[0024] In addition, the specific preparation process of the manganese dioxide of different crystal forms obtained in the subsequent examples is the same as the preparation process of Example 1.

[0025] The performance test of the δ-MnO2 catalyst prepared in Example 1 is as follows: Weigh 100 mg of catalyst into a high-pressure reactor, then weigh (0.5 g) of benzylamine and 20 mL of toluene and mix them evenly, then transfer the mixed solution into the high-pressure reactor, seal the high-pressure reactor and place it in a magnetic heating stirrer, first pass 0.1 MPa of O2 to check the airtightness of the high-pressure reactor, if there is no O2 leakage, discharge the O2 in the autoclave, fill and discharge the air three times to ensure that there is no air in the autoclave, and finally make the pressure of the high-pressure reactor reach 0.1 MPa.

[0026] Adjust the magnetic speed to 500 rpm, and start timing when the reactor temperature rises to 70 ℃. After 0.25 h of reaction, take out the reactor, let its temperature drop to room temperature, then open the gas valve of the autoclave to evacuate O2 until the pressure is 0MPa, and finally open the autoclave to take out the reaction liquid. Use a filter needle to extract and filter the reaction liquid, then use the gas chromatography micro-injection needle to draw 0.6 μl of the filtrate in the filtrate, and use gas chromatography for component analysis. The gas chromatography H2 flow rate is set to 50~80 mL / min, the air flow rate is 200~300 mL / min, the carrier gas flow rate is 3~5 mL / min, the injection temperature is set to 280.0 ℃, the column furnace initial temperature is set to 130 ℃ and maintained for 6 min, then the temperature is increased to 220 ℃ at 25 ℃ / min and maintained for 10 min, and the FID temperature is set to 280.0 ℃.

[0027] After the chromatographic peak emerges, the conversion rate of benzylamine is calculated by the peak area.

[0028] Under the reaction conditions of O2 pressure of 0.1 MPa, temperature of 70 ℃, reaction time of 0.25 h, δ-MnO2 of 100 mg, toluene of 20 mL and benzylamine of 0.5 g, the conversion rate of benzylamine by the catalyst reached 35.1%. When the reaction time was 9 h, the conversion rate of benzylamine could reach 99.9%. N -The selectivity of benzalkonium chloride is over 98.0% and it can be recycled four times.

[0029] Example 2: Preparation of δ-MnO2 1 mol / L potassium permanganate solution and 0.6 mol / L manganese sulfate solution were preheated to 85 °C respectively, and then the potassium permanganate solution at a feed rate of 60 g / min and the manganese sulfate solution at a feed rate of 100 g / min were simultaneously added to the reactor of the microfluidic reaction device for reaction to obtain δ-manganese dioxide.

[0030] Under the reaction conditions of O2 pressure of 0.1 MPa, temperature of 70 ℃, reaction time of 0.25 h, δ-MnO2 of 100 mg, toluene of 20 mL and benzylamine of 0.5 g, the conversion rate of benzylamine by the catalyst reached 30.1%. N -The selectivity of benzalkonium chloride is over 98.0%.

[0031] The reaction performance test conditions and steps for the application of the δ-MnO2 catalyst in this embodiment are the same as those in Example 1.

[0032] Example 3: Preparation of δ-MnO2 1 mol / L potassium permanganate solution and 1 mol / L manganese sulfate solution were preheated to 85 °C respectively, and then the potassium permanganate solution at a feed rate of 60 g / min and the manganese sulfate solution at a feed rate of 100 g / min were simultaneously added to the reactor of the microfluidic reaction device for reaction to obtain δ-manganese dioxide.

[0033] Under the reaction conditions of O2 pressure of 0.1 MPa, temperature of 70 ℃, reaction time of 0.25 h, δ-MnO2 of 100 mg, toluene of 20 mL and benzylamine of 0.5 g, the conversion rate of benzylamine by the catalyst reached 25.0%. N -The selectivity of benzalkonium chloride is over 98.0%.

[0034] The reaction performance test conditions and steps for the application of the δ-MnO2 catalyst in this embodiment are the same as those in Example 1.

[0035] Example 4: Preparation of δ-MnO2 1 mol / L potassium permanganate solution and 0.8 mol / L manganese sulfate solution were preheated to 85 °C respectively, and then the potassium permanganate solution at a feed rate of 60 g / min and the manganese sulfate solution at a feed rate of 80 g / min were simultaneously added to the reactor of the microfluidic reaction device for reaction to obtain δ-manganese dioxide.

[0036] Under the reaction conditions of O2 pressure of 0.1 MPa, temperature of 70 ℃, reaction time of 0.25 h, δ-MnO2 of 100 mg, toluene of 20 mL and benzylamine of 0.5 g, the conversion rate of benzylamine by the catalyst reached 20.3%. N -The selectivity of benzalkonium chloride is over 98.0%.

[0037] The reaction performance test conditions and steps for the application of the δ-MnO2 catalyst in this embodiment are the same as those in Example 1.

[0038] Example 5: Preparation of δ-MnO2 1 mol / L potassium permanganate solution and 0.8 mol / L manganese sulfate solution were preheated to 85 °C respectively, and then the potassium permanganate solution at a feed rate of 60 g / min and the manganese sulfate solution at a feed rate of 120 g / min were simultaneously added to the reactor of the microfluidic reaction device for reaction to obtain δ-manganese dioxide.

[0039] Under the reaction conditions of O2 pressure of 0.1 MPa, temperature of 70 ℃, reaction time of 0.25 h, δ-MnO2 of 100 mg, toluene of 20 mL and benzylamine of 0.5 g, the conversion rate of benzylamine by the catalyst reached 13.3%. N -The selectivity of benzalkonium chloride is over 98.0%.

[0040] The reaction performance test conditions and steps for the application of the δ-MnO2 catalyst in this embodiment are the same as those in Example 1.

[0041] Example 6: Preparation of α-MnO2 A 0.3 mol / L potassium permanganate solution and a 0.5 mol / L manganese sulfate solution were preheated to 60°C respectively, and then the potassium permanganate solution at a feed rate of 65 g / min and the manganese sulfate solution at a feed rate of 70 g / min were simultaneously added to the reactor of the microfluidic reaction device for reaction to obtain α-manganese dioxide.

[0042] Under the reaction conditions of O2 pressure of 0.1 MPa, temperature of 70 ℃, reaction time of 0.25 h, α-MnO2 of 100 mg, toluene of 20 mL and benzylamine of 0.5 g, the conversion rate of benzylamine by the catalyst reached 11.5%. N-The selectivity of benzalkonium chloride is over 97.0%.

[0043] The reaction performance test conditions and steps for the application of the α-MnO2 catalyst in this embodiment are the same as those in Example 1.

[0044] Example 7: Preparation of γ-MnO2 A 0.17 mol / L potassium permanganate solution and a 0.5 mol / L manganese sulfate solution were preheated to 90 °C respectively, and then the potassium permanganate solution at a feed rate of 65 g / min and the manganese sulfate solution at a feed rate of 70 g / min were simultaneously added to the reactor of the microfluidic reaction device for reaction to obtain γ-manganese dioxide.

[0045] Under the reaction conditions of O2 pressure of 0.1 MPa, temperature of 70 ℃, reaction time of 0.25 h, γ-MnO2 of 100 mg, toluene of 20 mL and benzylamine of 0.5 g, the conversion rate of benzylamine by the catalyst reached 5.5%. N -The selectivity of benzalkonium chloride is over 96.0%.

[0046] The application of the γ-MnO2 catalyst in this embodiment, and the reaction performance test conditions and steps are the same as those in Example 1.

[0047] The catalysts used in the following Examples 8 to 17 are all the δ-MnO2 catalysts prepared in Example 1.

[0048] Example 8: The mass of benzylamine is 0.25 g Under the reaction conditions of O2 pressure of 0.1 MPa, temperature of 70 ℃, reaction time of 0.25 h, δ-MnO2 of 100 mg, toluene of 20 mL and benzylamine of 0.25 g, the conversion rate of benzylamine by the catalyst reached 78.9%. N -The selectivity of benzylidenebenzylamine reaches over 98.8%.

[0049] The reaction performance test conditions and steps for the application of δ-MnO2 catalyst are the same as those in Example 1.

[0050] Example 9: The mass of benzylamine is 1.5 g Under the reaction conditions of O2 pressure of 0.1 MPa, temperature of 70 ℃, reaction time of 0.25 h, δ-MnO2 of 100 mg, toluene of 20 mL and benzylamine of 1.5 g, the conversion rate of benzylamine by the catalyst reached 10.3%. N -The selectivity of benzylidenebenzylamine reaches over 99.5%.

[0051] The reaction performance test conditions and steps for the application of δ-MnO2 catalyst are the same as those in Example 1.

[0052] Example 10: Reaction temperature is 50 °C Under the reaction conditions of O2 pressure of 0.1 MPa, temperature of 50 ℃, reaction time of 0.25 h, δ-MnO2 of 100 mg, toluene of 20 mL and benzylamine of 0.5 g, the conversion rate of benzylamine by the catalyst reached 18.8%. N -The selectivity of benzylidenebenzylamine reaches over 99.5%.

[0053] The reaction performance test conditions and steps for the application of δ-MnO2 catalyst are the same as those in Example 1.

[0054] Example 11: Reaction temperature is 60 °C Under the reaction conditions of O2 pressure 0.1 MPa, temperature 60 ℃, reaction time 0.25 h, δ-MnO2 100 mg, 20 mL toluene and benzylamine 0.5 g, the conversion rate of benzylamine by the catalyst reached 20.5%. N -The selectivity of benzylidenebenzylamine reaches over 99.0%.

[0055] The reaction performance test conditions and steps for the application of δ-MnO2 catalyst are the same as those in Example 1.

[0056] Example 12: Reaction temperature is 80 °C Under the reaction conditions of O2 pressure of 0.1 MPa, temperature of 80 ℃, reaction time of 0.25 h, δ-MnO2 of 100 mg, toluene of 20 mL and benzylamine of 0.5 g, the conversion rate of benzylamine by the catalyst reached 50.3%. N -The selectivity of benzylidenebenzylamine reaches over 97.5%.

[0057] The reaction performance test conditions and steps for the application of δ-MnO2 catalyst are the same as those in Example 1.

[0058] Example 13: Reaction temperature is 100 °C Under the reaction conditions of O2 pressure 0.1 MPa, temperature 100 ℃, reaction time 0.25 h, δ-MnO2 100 mg, 20 mL toluene and benzylamine 0.5 g, the conversion rate of benzylamine by the catalyst reached 70.6%. N -The selectivity of benzylidenebenzylamine reaches over 96.5%.

[0059] The reaction performance test conditions and steps for the application of δ-MnO2 catalyst are the same as those in Example 1.

[0060] Example 14: Reaction temperature is 120 °C Under the reaction conditions of O2 pressure of 0.1 MPa, temperature of 120 ℃, reaction time of 0.25 h, δ-MnO2 of 100 mg, toluene of 20 mL and benzylamine of 0.5 g, the conversion rate of benzylamine by the catalyst reached 99.9%. N -The selectivity of benzalkonium chloride is over 92.5%.

[0061] The reaction performance test conditions and steps for the application of δ-MnO2 catalyst are the same as those in Example 1.

[0062] Example 15: Reaction temperature is 150 °C Under the reaction conditions of O2 pressure of 0.1 MPa, temperature of 150 ℃, reaction time of 0.25 h, δ-MnO2 of 100 mg, toluene of 20 mL and benzylamine of 0.5 g, the conversion rate of benzylamine by the catalyst reached 99.9%. N -The selectivity of benzalkonium chloride is over 90.0%.

[0063] The reaction performance test conditions and steps for the application of δ-MnO2 catalyst are the same as those in Example 1.

[0064] Example 16: Oxygen reaction pressure is 0.5 MPa Under the reaction conditions of O2 pressure 0.5MPa, temperature 70℃, reaction time 0.25h, δ-MnO2 100mg, 20mL toluene and benzylamine 0.5g, the conversion rate of benzylamine by the catalyst reached 35.0%. N -The selectivity of benzalkonium chloride is over 97.0%.

[0065] The reaction performance test conditions and steps for the application of δ-MnO2 catalyst are the same as those in Example 1.

[0066] Example 17: Oxygen reaction pressure is 1 MPa Under the reaction conditions of O2 pressure 1 MPa, temperature 70 ℃, reaction time 0.25 h, δ-MnO2 100 mg, 20 mL toluene and benzylamine 0.5 g, the conversion rate of benzylamine by the catalyst reached 35.1%. N -The selectivity of benzalkonium chloride reached 96.0%.

[0067] The reaction performance test conditions and steps for the application of δ-MnO2 catalyst are the same as those in Example 1.

[0068] For the XRD diagram of the δ-MnO2 catalyst prepared in Example 1 of the present invention, it can be seen from the figure that there are six diffraction peaks at approximately 2θ=12.51°, 25.21°, 37.31°, 40.01° and 66.21°, corresponding to the six crystal planes of the crystal (001), (002), (100), (201) and (110).

[0069] Figure 2 This is the XRD diagram of α-MnO2 catalyst. It can be seen from the figure that there are 14 diffraction peaks at approximately 2θ=12.71°, 18.11°, 25.71°, 28.81°, 37.51°, 39.01°, 41.91°, 47.31°, 49.81°, 56.31°, 60.21°, 65.11°, 69.71° and 72.71°, corresponding to the 14 crystal planes of the crystal: (110), (200), (220), (310), (211), (330), (301), (510), (411), (600), (521), (002), (541) and (312).

[0070] Figure 3 This is the XRD diagram of the γ-MnO2 catalyst. It can be seen from the figure that there are 6 diffraction peaks at approximately 2θ=22.41°, 34.41°, 38.71°, 42.61°, 57.31°, and 68.81°, corresponding to the 6 crystal planes of the crystal: (120), (031), (131), (300), (160) and (003).

[0071] Figure 4 The transmission electron microscope images of three different crystalline γ-MnO2 catalysts show that Figure 4 (a) The δ-MnO2 catalyst consists of a spherical daisy structure composed of stacked nanosheets. Figure 4 (b) The α-MnO2 catalyst is in the form of nanofibers. Figure 4 (c) The γ-MnO2 catalyst presents a grain-like structure. From the perspective of morphology, the δ-MnO2 catalyst has a spherical daisy structure composed of stacked nanosheets. Compared with α-MnO2 and γ-MnO2 catalysts, δ-MnO2 can expose more active sites and contact areas with substrate benzylamine and oxygen. Therefore, the catalytic activity of the δ-MnO2 catalyst is higher than that of the α-MnO2 and γ-MnO2 catalysts.

[0072] Figure 5is the time course analysis diagram of δ-MnO2 catalyst. It can be seen from the figure that when the reaction time is 0 h, 0.125 h, 0.25 h, 0.5 h, 1 h, 2 h, 4 h, 8 h and 9 h, the conversion rate of benzylamine is 0.0%, 20.5%, 35.1%, 44.3%, 55.6%, 66.5%, 81.3%, 99.2% and 99.9%, respectively. N The selectivity of -benzylidenebenzylamine was maintained above 98.0%, which shows that the δ-MnO2 catalyst has a high catalytic activity.

[0073] Figure 6 The stability experimental performance diagram of δ-MnO2 catalyst (Fig. Represents the conversion rate of benzylamine, and the blue bar represents N -benzylidenebenzylamine selectivity), as can be seen from the figure, when the catalyst cycle number is the first, second, third and fourth times, the conversion rate of benzylamine is 35.1%, 35.1%, 35.0% and 35.1% respectively, N The selectivity of -benzylidenebenzylamine was maintained above 98.0%, which shows that the δ-MnO2 catalyst has high stability.

[0074] The catalytic performance of three crystalline manganese dioxide catalysts for benzylamine under the same reaction conditions is shown in Table 1.

[0075] Table 1

[0076] The reaction conditions in Table 1 are: 0.5 g benzylamine, 100 mg catalyst, reaction temperature 70 °C, oxygen pressure 0.1 MPa, 20 mL toluene, and reaction time 9 h.

[0077] Through the data analysis in Table 1, it is found that the δ-MnO2 catalyst can achieve the complete catalytic conversion of benzylamine into N -benzylidenebenzylamine, it can be concluded that δ-MnO2 has the best performance under the same reaction conditions.

[0078] The experimental performance diagram of the catalytic stability of three crystalline manganese dioxide catalysts on benzylamine under the same reaction conditions is shown in Table 2.

[0079] Table 2

[0080] The reaction conditions in Table 2 are: 0.5 g benzylamine, 100 mg catalyst, reaction temperature 70 °C, oxygen pressure 0.1 MPa, 20 mL toluene, and reaction time 0.25 h.

[0081] By analyzing the data in Table 2, the catalytic stability experimental performance of δ-MnO2 catalyst for benzylamine under the same reaction conditions can be concluded that δ-MnO2 has the best performance under the same reaction conditions.

[0082] Through Examples 1, 10 to 15, it can be seen that the catalytic performance of the δ-MnO2 catalyst for benzylamine under different temperature reaction conditions is shown in Table 3.

[0083] Table 3

[0084] The reaction conditions in Table 3 are: 0.5 g benzylamine, 100 mg catalyst, reaction temperature 70 °C, oxygen pressure 0.1 MPa, 20 mL toluene, and reaction time 0.25 h.

[0085] By analyzing the data in Table 3, we can study the catalytic performance of δ-MnO2 catalyst for benzylamine at different reaction temperatures. It can be concluded that under the same reaction conditions, as the reaction temperature increases, the conversion rate of δ-MnO2 catalyst for benzylamine increases continuously, but N The selectivity of -benzylidenebenzylamine decreases with increasing temperature because the increase in temperature leads to excessive oxidation, which results in an increase in by-products. N -The selectivity of benzylidenebenzylamine decreases.

[0086] Through the data analysis of Example 1, Example 16 and Example 17, the catalytic performance of δ-MnO2 catalyst on benzylamine under different pressure conditions can be concluded that under different pressure conditions, the δ-MnO2 catalyst has little effect on the conversion rate of benzylamine. N The selectivity of -benzylidenebenzylamine is more obvious, because the higher the oxygen pressure, the more by-products will be produced due to over-oxidation. Therefore, the catalytic performance of δ-MnO2 is the best under 0.1 MPa O2 conditions.

[0087] Through the data analysis of Example 1, Example 8 and Example 9, the catalytic performance of the δ-MnO2 catalyst for benzylamine under different concentrations of benzylamine can be concluded that under different reactant concentrations, too high or too low concentrations of benzylamine will affect the conversion rate of the catalyst for benzylamine. Since the adsorption of benzylamine by the catalyst is very weak, the catalytic activity changes with the concentration of benzylamine.

[0088] The above description is only part of the embodiments of the present invention and is not intended to limit the present invention. All equivalent changes and modifications made according to the content of the present invention are within the protection scope of the present invention.

Claims

1. Preparation of benzylamine by catalysis of delta-crystalline manganese dioxide N - application of benzylidenebenzylamine, characterized in that, Using delta crystal manganese dioxide as catalyst and toluene as solvent, benzylamine is catalyzed to undergo oxidative self-coupling reaction in an oxygen atmosphere to prepare N -benzylidenebenzylamine.

2. The use according to claim 1, characterized in that: Under the reaction conditions of 0.1 MPa O2 pressure, 70 °C reaction temperature and 0.25 h reaction time, the conversion rate of benzylamine reached 35.1%. After 9 h of reaction, the conversion rate of benzylamine reached 99.9%. N The selectivity of -benzylidenebenzylamine reached over 98.0%.

3. The use according to claim 1, characterized in that: The preparation steps of delta crystalline manganese dioxide are as follows: (1) Preheat the potassium permanganate solution and the manganese sulfate solution to a temperature T, 80 ℃ ≤ T < 90 ℃ respectively; (2) Adding potassium permanganate solution and manganese sulfate solution into the reactor of the microfluidic reaction device at the same time, reacting at a constant temperature, the reaction temperature is 80 ℃ ≤ T < 90 ℃, and the reaction time is 1 h; (3) The product obtained by the reaction was allowed to stand for 24 hours, filtered and washed until the pH value was 7, and dried at a constant temperature of 80°C. After cooling to room temperature, the product was ground to obtain delta crystalline manganese dioxide.

4. The use according to claim 1, characterized in that: In the step (1) of preparing the delta crystalline manganese dioxide, the feed concentration c1 of the potassium permanganate solution is controlled to be 0 mol / L<c1≤1 mol / L.

5. The use according to claim 1, characterized in that: In the step (1) of preparing the delta crystalline manganese dioxide, the feeding concentration c2 of the manganese sulfate solution is controlled to be 0 mol / L<c2≤1 mol / L.

6. The use according to claim 1, characterized in that: In the step (2) of preparing the delta crystalline manganese dioxide, the feed flow rate Q1 of the potassium permanganate solution is controlled to be 60 g / min≤Q1≤80 g / min.

7. The use according to claim 1, characterized in that: In the step (2) of preparing the delta crystalline manganese dioxide, the feed flow rate Q2 of the manganese sulfate solution is controlled to be 70 g / min≤Q2≤120 g / min.

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