Heterogeneous catalyst for synthesizing methyl phenylcarbamate as well as preparation method and application of heterogeneous catalyst
By supporting the active components, a high-activity and stable carbon-based heterogeneous catalyst was prepared, which solved the problems of low catalyst activity and easy loss in the prior art, and achieved the industrial application of efficient synthesis of methyl aphrocarbamate prospect.
Patent Information
- Application Number
- CN202310769505.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-06-27
- Publication Date
- 2024-12-31
AI Technical Summary
The current heterogeneous catalysts used for the synthesis of methyl alecarbamate have low activity, are difficult to form and are easily lost, and are also difficult to dissolve in the reaction system and are difficult to separate from the product.
The method of supporting the active components is carbon, and the active components are zinc and/or bismuth. The heterogeneous catalyst is prepared by carbonization of a modified chloromethyl resin, and the modified chloromethyl resin is mixed with a metal precursor solution. And calcined to form a spherical carbon-based heterogeneous catalyst.
The activity and stability of the catalyst are improved, and the problems of difficult separation of homogeneous catalysts and easy loss of active components of heterogeneous catalysts are solved, thus achieving efficient synthesis of methyl aphrodisiac, improving the efficiency of support utilization and active center density.
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Figure CN119215996A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of heterogeneous catalysts and preparation of methyl phenylcarbamate, and in particular relates to a heterogeneous catalyst for synthesizing methyl phenylcarbamate, and a preparation method and application thereof. Background Art
[0002] Isocyanate is an important raw material for the production of polyurethane. The existing mature isocyanate processes all use the phosgene method. The phosgene production technology is mature and economically reasonable. From the perspective of production cost, it will remain the mainstream production process for some time to come. However, the production process of MDI by the phosgene method has the following inherent problems: the raw material phosgene is a highly toxic gas, which poses a great safety hazard in the production process and is unfriendly to the environment and personnel; there is a large amount of by-product hydrogen chloride in the phosgenation production, which seriously corrodes the equipment in the production process, so the requirements for equipment materials are high and the investment is large; there will be chlorine in the product isocyanate product, which affects the application performance of the product. Therefore, isocyanate manufacturers around the world are actively developing non-phosgene isocyanate processes.
[0003] The production of the intermediate methyl phenylcarbamate is the key to the industrialization of this technical route. The Lewis acid catalyst used earlier was uranium compounds. William.F et al. used Lewis acids such as uranium compounds and antimony compounds as catalysts to synthesize IV-substituted methyl carbamates. Using uranyl nitrate [UO2(NO3)2] as a catalyst, the reaction was carried out at 150℃ for 6h, and the MPC yield was only 20.0%, which was not ideal. In addition, uranium compounds had reflective pollution and high cost. Alkali metal and alkaline earth metal carbonates and alcohol salts also showed certain catalytic activity, low cost and easy preparation. Kang Wukui et al. investigated the catalytic performance of Pd, Ti, Sn, and Zn metal oxide catalysts for the synthesis of MPC by the reaction of dimethyl carbonate and aniline, and found that lead oxide had the best activity. When the catalyst dosage was 7.5%, the aniline conversion rate reached 78%. Li Qifeng et al. investigated the effects of different carriers on the performance of loaded lead oxide and screened out silica carriers with better activity. Jiang Zhaobo et al. used CXS as a catalyst to investigate the influence of the size of the system reaction material ratio, reaction time, reaction temperature and other factors and conditions on the synthesis of MPC. The results showed that with CSX as a catalyst, the yield of MPC could reach 94% and the selectivity was 96.4% in an open system at 150°C and n(DMC):n(AN)=5:1 for 3h. Fan Yapeng et al. investigated the influence of different common carriers on zinc acetate and found that activated carbon was the best negative body of zinc acetate. Compared with the uncured catalytic effect, it significantly improved the aniline conversion rate and product selectivity. The effects of different loading amounts and catalyst dosages on the reaction were investigated, and the optimal loading amount of Zn(OAc)2 on activated carbon was determined to be 10%. It can be seen that the main development work is still based on homogeneous catalytic systems, but there are disadvantages such as homogeneous catalysts dissolving in the reaction system, difficulty in separation from the product, and instability during the reaction. The development of heterogeneous catalytic systems is mainly based on oxides, and the catalytic system has low activity, is difficult to form, and is easy to lose. Summary of the invention
[0004] Aiming at the problems that the existing heterogeneous catalyst for synthesizing methyl phenylcarbamate has low activity, is difficult to form, is easy to lose, etc., the present invention provides a heterogeneous catalyst for synthesizing methyl phenylcarbamate, a preparation method and application thereof.
[0005] In order to solve the above technical problems, the first aspect of the present invention provides a method for preparing a heterogeneous catalyst for synthesizing methyl phenylcarbamate, the preparation method comprising the step of using a carrier to load an active component; the carrier is carbon, and the active component is zinc and / or bismuth, wherein zinc and bismuth exist in the form of a single substance.
[0006] According to some embodiments of the present invention, the carbon is obtained by carbonizing a modified chloromethyl resin. Specifically, after loading the active component, the modified chloromethyl resin is subjected to high-temperature calcination, and during the calcination process, the modified chloromethyl resin is carbonized to generate carbon. When preparing the modified chloromethyl resin, the chloromethyl resin is mixed with a solvent, and a modifier is added to modify the modified chloromethyl resin. The modifier is a nitrogen-containing five-membered or six-membered heterocyclic aromatic compound, wherein the ring-forming skeleton of the five-membered or six-membered heterocyclic aromatic compound contains at least one nitrogen atom.
[0007] According to some embodiments of the present invention, the modified chloromethyl resin is a modified chloromethyl styrene resin or a modified chloromethyl carboxylic acid resin.
[0008] According to some embodiments of the present invention, the chloromethyl resin is a styrene-based or carboxylic acid-based resin; the particle size of the chloromethyl resin is 0.1 mm to 3 mm, preferably 0.3 mm to 2 mm; preferably, the chloromethyl resin is spherical;
[0009] and / or, the modifier is at least one of piperazine, imidazole and pyridine;
[0010] and / or, the solvent is at least one of toluene, methanol, ethanol, n-propanol, n-butanol, isobutanol or tert-butanol, tetrahydrofuran, dichloromethane, chloroform, N,N-dimethylformamide, ether and water;
[0011] And / or, the mass ratio of the chloromethyl resin to the solvent is 1:(1-10), preferably 1:(2-8), for example 1:3.792, 1:5.688;
[0012] and / or, the mass ratio of the chloromethyl resin to the modifier is 1:(0.1-1.2), preferably 1:(0.15-1), for example 1:0.6, 1:0.8, 1:1;
[0013] And / or, before adding the modifier, a stirring and heating step is included; the stirring rate is 50 rpm to 1000 rpm, preferably 100 rpm to 800 rpm, for example 500 rpm, 800 rpm; the stirring time is 1h to 24h, preferably 2h to 18h, for example 2h; the temperature after heating is 30°C to 150°C, preferably 40°C to 120°C, for example 70°C, 80°C, 90°C;
[0014] and / or, the modification time is 1 h to 24 h, preferably 2 h to 18 h, for example 12 h, 15 h;
[0015] And / or, after the modification, the process further comprises cooling, separating, washing the product, and drying the product; preferably, the drying temperature is 80°C to 180°C, such as 100°C or 120°C; and the drying time is 1h to 48h, such as 24h.
[0016] According to some embodiments of the present invention, when a carrier is used to load the active component, the carrier is mixed with a metal precursor solution containing the active component, dried, and then calcined in an inert gas atmosphere to obtain the heterogeneous catalyst.
[0017] According to some embodiments of the present invention, the metal precursor solution containing active components is at least one of a nitrate solution, a chloride solution, and a sulfate solution of zinc and / or bismuth, and the mass concentration of the metal precursor solution containing active components is 0.05% to 3%, for example, 0.12%, 0.14%, 0.146%, 0.23%, 0.25%, 0.33%, 0.45%, and 0.48%.
[0018] According to some embodiments of the present invention, when a carrier is used to load an active component, the mass ratio of the carrier to the metal precursor solution containing the active component is 1:(1-10), preferably 1:(2-6), for example 1:2.5, 1:3, 1:4, 1:5, 1:6;
[0019] And / or, after the carrier is mixed with the metal precursor solution containing the active component, a heating and stirring step is further included, wherein the heating temperature is 20°C to 100°C, for example, 30°C, 50°C; the stirring rate is 100 rpm to 800 rpm, and the stirring time is 0.5h to 10h, for example, 2h, 6h, 8h;
[0020] And or, the drying temperature is 80°C to 180°C, for example 100°C, and the drying time is 1h to 48h, for example 24h;
[0021] and / or, the inert gas is nitrogen or argon;
[0022] And / or, the calcination temperature is 200°C to 1000°C, preferably 250°C to 800°C, such as 400°C or 500°C, and the calcination time is 1h to 48h, preferably 2h to 24h, such as 4h, 5h or 8h.
[0023] The second aspect of the present invention provides a heterogeneous catalyst for synthesizing methyl phenylcarbamate prepared by the above-mentioned preparation method, comprising a carrier and an active component, wherein the mass percentages of the carrier and the active component in the heterogeneous catalyst are: 90.0% to 99.9% of the carrier and 0.1% to 10% of the active component; the carrier is carbon, and the active component is zinc and / or bismuth, wherein zinc and bismuth exist in the form of simple substances.
[0024] According to some embodiments of the present invention, the particle size of the heterogeneous catalyst is 0.1 mm to 3 mm, preferably 0.3 mm to 2 mm.
[0025] The third aspect of the present invention provides a method for synthesizing methyl phenylcarbamate, comprising the step of reacting aniline and dimethyl carbonate under the action of a heterogeneous catalyst to obtain methyl phenylcarbamate; the heterogeneous catalyst is a heterogeneous catalyst for synthesizing methyl phenylcarbamate prepared by the above preparation method.
[0026] According to some embodiments of the present invention, the reaction is carried out in an intermittent reactor, preferably, the reaction temperature is 80°C to 200°C, such as 100°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C; the reaction time is 2h to 8h, such as 3h, 4h, 5h, 6h, 7h, 8h;
[0027] and / or, the molar ratio of aniline to dimethyl carbonate is 1:(1-15), preferably 1:(2-10), for example 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:10;
[0028] And / or, the mass ratio of the heterogeneous catalyst to dimethyl carbonate is 1:(1-20), for example, 1:3.3, 1:3.7, 1:6.35, 1:10, 1:20.
[0029] Beneficial effects:
[0030] When the heterogeneous catalyst for synthesizing methyl phenylcarbamate provided by the present invention is applied to the preparation method of methyl phenylcarbamate, in a circulating multiphase reactor, dimethyl carbonate and aniline are fed and reacted at 80-120° C. for a specified time to obtain the product methyl phenylcarbamate. The heterogeneous catalyst has high reaction activity and good stability and has good industrial application prospects.
[0031] The preparation method of the heterogeneous catalyst for synthesizing methyl phenylcarbamate of the present invention adopts a loaded spherical modified oxide heterogeneous catalyst, effectively improves the carrier utilization rate and the active center density, and solves the problem of difficult separation of homogeneous catalysts in the prior art; in addition, the heterogeneous catalyst for synthesizing methyl phenylcarbamate has stable properties in the system, and the active center is not easy to lose, which solves the problem of easy loss of active components of the heterogeneous catalyst in the prior art.
[0032] When the heterogeneous catalyst for synthesizing methyl phenylcarbamate of the present invention is used in the preparation method of methyl phenylcarbamate, under the conditions of reaction temperature of 170°C, molar ratio of dimethyl carbonate to aniline of 10:1, and mass ratio of heterogeneous catalyst for synthesizing methyl phenylcarbamate to aniline of 0.1:1, the reaction is carried out for 3 hours, the conversion rate of aniline is 99.7%, the selectivity of methyl phenylcarbamate is 96.2%, and the activity of the heterogeneous catalyst for synthesizing methyl phenylcarbamate decreases by less than 5% after being reused for 5 times, thereby achieving good technical effect. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] Figure 1 This is a scanning electron microscope image of the heterogeneous catalyst C1 prepared in Example 1 of the present invention;
[0034] Figure 2 This is a scanning electron microscope image of the heterogeneous catalyst S1 prepared in Comparative Example 1 of the present invention;
[0035] Figure 3 XRD patterns of heterogeneous catalysts C1 and S1 prepared in Example 1 and Comparative Example 1 of the present invention;
[0036] Figure 4 This is a projection electron micrograph of the heterogeneous catalyst C1 prepared in Example 1 of the present invention;
[0037] Figure 5 This is a projection electron microscope image of the heterogeneous catalyst S1 prepared in Comparative Example 1 of the present invention. DETAILED DESCRIPTION
[0038] The present invention will be further described below in conjunction with the embodiments, but the present invention is not limited by these embodiments.
[0039] The gas chromatograph in the present invention is an Agilent 7890 chromatograph. The analysis conditions are: chromatographic column HP-FFAP, injection port temperature 280°C, FID detector, column box program heating, 50°C for 3 minutes, then heating to 230°C at 10°C / min for 10 minutes, split ratio 50:1, and component content analysis by calibration normalization method.
[0040] The conversion rate of aniline in the present invention is calculated as follows: (mass of input aniline - mass of product after reaction * aniline content) / mass of input aniline * 100%.
[0041] The selectivity calculation method of methyl phenylcarbamate in the present invention is: total material after reaction*mass fraction of methyl phenylcarbamate*93 / 137 / mass of converted aniline*100%.
[0042] Example 1
[0043] This embodiment provides a method for synthesizing methyl phenylcarbamate:
[0044] Preparation of heterogeneous catalyst for synthesizing methyl phenylcarbamate: In a 500 ml three-necked flask, add 50 g of chloromethylstyrene resin and 200 ml (189.6 g) of N,N-dimethylformamide, stir at 500 rpm for 2 h, heat to 90° C., add 50 g of imidazole, keep warm for 12 h, cool and separate the product, wash with deionized water, and dry the product at 100° C. for 24 h to obtain the improved catalyst. Then, in another 500ml three-necked flask, add 20g of modified resin, 0.073g of bismuth nitrate and water to prepare a 50g solution, stir at 30°C at a rate of 500 rpm for 6h, put into an oven at 100°C for drying for 24h, transfer to a muffle furnace, and calcine at 500°C for 5h under a nitrogen atmosphere to obtain a heterogeneous catalyst C1, the mass percentage of bismuth in C1 is 1.0%. The scanning electron microscope image of C1 is as follows Figure 1 As shown, the transmission electron microscope image of C1 is as follows Figure 4 As shown, the XRD pattern of C1 is Figure 3 As shown, Figure 3 The XRD curve representing C1 is located below the XRD curve representing S1.
[0045] In the above-mentioned heterogeneous catalyst preparation process, the chloromethylstyrene resin is spherical and has a particle size of 0.5 mm.
[0046] Preparation of methyl phenylcarbamate: 4.65 g (0.05 mol) of aniline, 45 g (0.5 mol) of dimethyl carbonate and 4.8 g of heterogeneous catalyst C1 were placed in a 100 mL autoclave and reacted at a temperature of 170° C. for 3 h, wherein the molar ratio of dimethyl carbonate to aniline was 10:1, and the mass ratio of heterogeneous catalyst C1 to dimethyl carbonate was 0.1:1. After the reaction, the autoclave was cooled to room temperature and vented; the liquid product was taken for gas chromatography analysis and calculated, and the conversion rate of aniline was 99.7%, and the selectivity of methyl phenylcarbamate was 96.2%.
[0047] Example 2
[0048] This embodiment provides a method for synthesizing methyl phenylcarbamate:
[0049] Preparation of heterogeneous catalyst for synthesizing methyl phenylcarbamate: In a 500 ml three-necked flask, add 50 g of chloromethylstyrene resin and 200 ml (189.6 g) of N,N-dimethylformamide, stir at 500 rpm for 2 h, heat to 90° C., add 50 g of imidazole, keep warm for 12 h, cool and separate the product, wash with deionized water, and dry the product at 100° C. for 24 h to obtain the improved catalyst. then in another 500ml three-necked flask, add 20g of modified resin, 0.073g of bismuth nitrate and water to prepare 60g of solution, stir at 50°C at a rate of 600 rpm for 8h, put into an oven at 100°C for drying for 24h, transfer to a muffle furnace, and calcine at 400°C for 8h under a nitrogen atmosphere to obtain a heterogeneous catalyst C2, wherein the mass percentage of bismuth in C2 is 1.0%.
[0050] In the above-mentioned heterogeneous catalyst preparation process, the chloromethylstyrene resin is spherical and has a particle size of 0.9 mm.
[0051] Preparation of methyl phenylcarbamate: 4.65 g (0.05 mol) of aniline, 36 g (0.4 mol) of dimethyl carbonate and 1.9 g of heterogeneous catalyst C2 are placed in a 100 mL autoclave and reacted at a temperature of 170° C. for 8 h, wherein the molar ratio of dimethyl carbonate to aniline is 8:1, and the mass ratio of heterogeneous catalyst C2 to dimethyl carbonate is 0.05:1. After the reaction is completed, the autoclave is cooled to room temperature and vented; the liquid product is taken for gas chromatography analysis and calculated, and the conversion rate of aniline is 99.5%, and the selectivity of methyl phenylcarbamate is 95.6%.
[0052] Example 3
[0053] This embodiment provides a method for synthesizing methyl phenylcarbamate:
[0054] Preparation of heterogeneous catalyst for synthesizing methyl phenylcarbamate: In a 500 ml three-necked flask, add 50 g of chloromethylstyrene resin and 300 ml (284.4 g) of N,N-dimethylformamide, stir at 800 rpm for 2 h, heat to 80° C., add 40 g of imidazole, keep warm for 12 h, cool and separate the product, wash with deionized water, and dry the product at 120° C. for 24 h to obtain the improved catalyst. then, in another 500ml three-necked flask, 20g of the modified resin and 0.073g of magnesium nitrate were added into water to prepare a 60g solution, and the solution was stirred at 400 rpm at 50°C for 8h, placed in an oven at 100°C for drying for 24h, and then transferred into a muffle furnace and calcined at 500°C for 4h under a nitrogen atmosphere to obtain a heterogeneous catalyst C3, wherein the mass percentage of bismuth in C3 was 1.0%.
[0055] In the above-mentioned heterogeneous catalyst preparation process, the chloromethylstyrene resin is spherical with a particle size of 0.7 mm.
[0056] Preparation of methyl phenylcarbamate: 4.65 g (0.05 mol) of aniline, 27 g (0.3 mol) of dimethyl carbonate and 2.9 g of heterogeneous catalyst C3 are placed in a 100 mL autoclave and reacted at a temperature of 170° C. for 5 h, wherein the molar ratio of dimethyl carbonate to aniline is 6:1, and the mass ratio of heterogeneous catalyst C3 to dimethyl carbonate is 0.1:1. After the reaction, the autoclave is cooled to room temperature and vented; the liquid product is taken for gas chromatography analysis and calculated, and the conversion rate of aniline is 98.7%, and the selectivity of methyl phenylcarbamate is 94.5%.
[0057] Example 4
[0058] This embodiment provides a method for synthesizing methyl phenylcarbamate:
[0059] Preparation of heterogeneous catalyst for synthesizing methyl phenylcarbamate: In a 500 ml three-necked flask, add 50 g of chloromethylstyrene resin and 300 ml (284.4 g) of N,N-dimethylformamide, stir at 800 rpm for 2 h, heat to 70° C., add 30 g of imidazole, keep warm for 15 h, cool and separate the product, wash with deionized water, and dry the product at 120° C. for 24 h to obtain the improved catalyst. then in another 500ml three-necked flask, add 20g of modified resin, 0.073g of bismuth nitrate and water to prepare 60g of solution, stir at 500 rpm for 2h at 50°C, put into an oven at 100°C for drying for 24h, transfer to a muffle furnace, and calcine at 500°C for 4h under a nitrogen atmosphere to obtain a heterogeneous catalyst C4, wherein the mass percentage of bismuth in C4 is 1.0%.
[0060] In the above-mentioned heterogeneous catalyst preparation process, the chloromethylstyrene resin is spherical and has a particle size of 1.0 mm.
[0061] Preparation of methyl phenylcarbamate: 4.65 g (0.05 mol) of aniline, 18 g (0.2 mol) of dimethyl carbonate and 1.9 g of heterogeneous catalyst C4 are placed in a 100 mL autoclave and reacted at a temperature of 170° C. for 6 h, wherein the molar ratio of dimethyl carbonate to aniline is 4:1, and the mass ratio of heterogeneous catalyst C4 to dimethyl carbonate is 0.1:1. After the reaction is completed, the autoclave is cooled to room temperature and vented; the liquid product is taken for gas chromatography analysis and calculated, and the conversion rate of aniline is 95.5%, and the selectivity of methyl phenylcarbamate is 91.5%.
[0062] Example 5
[0063] This embodiment provides a method for synthesizing methyl phenylcarbamate:
[0064] Preparation of heterogeneous catalyst for synthesizing methyl phenylcarbamate: In a 500 ml three-necked flask, add 50 g of chloromethylstyrene resin and 300 ml (284.4 g) of N,N-dimethylformamide, stir at 800 rpm for 2 h, heat to 70° C., add 30 g of imidazole, keep warm for 15 h, cool and separate the product, wash with deionized water, and dry the product at 120° C. for 24 h to obtain Modified resin; then in another 500ml three-necked flask, add 20g of modified resin, 0.73g of bismuth nitrate and water to prepare 60g of solution, stir at 50°C at a rate of 600 rpm for 2h, put into an oven at 100°C for drying for 24h, transfer to a muffle furnace, and calcine at 500°C for 4h under a nitrogen atmosphere to obtain a heterogeneous catalyst C5, the mass percentage of bismuth in C5 is 1.0%.
[0065] In the above-mentioned heterogeneous catalyst preparation process, the chloromethylstyrene resin is spherical and has a particle size of 1.0 mm.
[0066] Preparation of methyl phenylcarbamate: 4.65 g (0.05 mol) of aniline, 13.5 g (0.15 mol) of dimethyl carbonate and 1.4 g of heterogeneous catalyst C5 are placed in a 100 mL autoclave and reacted at 170° C. for 7 h, wherein the molar ratio of dimethyl carbonate to aniline is 3:1, and the mass ratio of heterogeneous catalyst C5 to dimethyl carbonate is 0.1:1. After the reaction, the autoclave is cooled to room temperature and vented; the liquid product is taken for gas chromatography analysis and calculated, and the conversion rate of aniline is 94.7%, and the selectivity of methyl phenylcarbamate is 90.7%.
[0067] Example 6
[0068] This embodiment provides a method for synthesizing methyl phenylcarbamate:
[0069] Preparation of heterogeneous catalyst for synthesizing methyl phenylcarbamate: In a 500 ml three-necked flask, add 50 g of chloromethylstyrene resin and 300 ml (284.4 g) of N,N-dimethylformamide, stir at 800 rpm for 2 h, heat to 70° C., add 30 g of imidazole, keep warm for 15 h, cool and separate the product, wash with deionized water, and dry the product at 120° C. for 24 h to obtain Modified resin; then in another 500ml three-necked flask, add 20g of modified resin, 0.15g of bismuth nitrate and water to prepare 60g of solution, stir at 50°C at a rate of 600 rpm for 2h, put into an oven at 100°C for drying for 24h, transfer to a muffle furnace, and calcine at 500°C for 4h under a nitrogen atmosphere to obtain a heterogeneous catalyst C6, the mass percentage of bismuth in C6 is 2.0%.
[0070] In the above-mentioned heterogeneous catalyst preparation process, the chloromethylstyrene resin is spherical and has a particle size of 1.0 mm.
[0071] Preparation of methyl phenylcarbamate: 4.65 g (0.05 mol) of aniline, 31.5 g (0.35 mol) of dimethyl carbonate and 3.4 g of heterogeneous catalyst C6 are placed in a 100 mL autoclave and reacted at a temperature of 150° C. for 8 hours, wherein the molar ratio of dimethyl carbonate to aniline is 7:1, and the mass ratio of heterogeneous catalyst C6 to dimethyl carbonate is 0.1:1. After the reaction is completed, the autoclave is cooled to room temperature and vented; the liquid product is taken for gas chromatography analysis and calculated, and the conversion rate of aniline is 99.5%, and the selectivity of methyl phenylcarbamate is 95.6%.
[0072] Example 7
[0073] This embodiment provides a method for synthesizing methyl phenylcarbamate:
[0074] Preparation of heterogeneous catalyst for synthesizing methyl phenylcarbamate: In a 500 ml three-necked flask, add 50 g of chloromethylstyrene resin and 300 ml (284.4 g) of N,N-dimethylformamide, stir at 800 rpm for 2 h, heat to 70° C., add 30 g of imidazole, keep warm for 15 h, cool and separate the product, wash with deionized water, and dry the product at 120° C. for 24 h to obtain Modified resin; then in another 500ml three-necked flask, add 20g of modified resin, 0.36g of bismuth nitrate and water to prepare 80g of solution, stir at 500 rpm for 2h at 50°C, put into an oven at 100°C for drying for 24h, transfer to a muffle furnace, and calcine at 500°C for 4h under a nitrogen atmosphere to obtain a heterogeneous catalyst C7, the mass percentage of bismuth in C7 is 5.0%.
[0075] In the above-mentioned heterogeneous catalyst preparation process, the chloromethylstyrene resin is spherical and has a particle size of 1.0 mm.
[0076] Preparation of methyl phenylcarbamate: 4.65 g (0.05 mol) of aniline, 22.5 g (0.25 mol) of dimethyl carbonate and 3.6 g of heterogeneous catalyst C7 were placed in a 100 mL autoclave and reacted at a temperature of 130° C. for 7 h, wherein the molar ratio of dimethyl carbonate to aniline was 5:1, and the mass ratio of heterogeneous catalyst C7 to dimethyl carbonate was 0.16:1. After the reaction, the autoclave was cooled to room temperature and vented; the liquid product was taken for gas chromatography analysis and calculated, and the conversion rate of aniline was 98.5%, and the selectivity of methyl phenylcarbamate was 92.6%.
[0077] Example 8
[0078] This embodiment provides a method for synthesizing methyl phenylcarbamate:
[0079] Preparation of heterogeneous catalyst for synthesizing methyl phenylcarbamate: In a 500 ml three-necked flask, add 50 g of chloromethylstyrene resin and 300 ml (284.4 g) of N,N-dimethylformamide, stir at 800 rpm for 2 h, heat to 70° C., add 30 g of imidazole, keep warm for 15 h, cool and separate the product, wash with deionized water, and dry the product at 120° C. for 24 h to obtain the improved catalyst. then in another 500ml three-necked flask, add 20g of modified resin, 0.58g of bismuth nitrate and water to prepare 120g of solution, stir at 700 rpm at 50°C for 2h, put into an oven at 100°C for drying for 24h, transfer to a muffle furnace, and calcine at 500°C for 4h under a nitrogen atmosphere to obtain a heterogeneous catalyst C8, wherein the mass percentage of bismuth in C8 is 8.0%.
[0080] In the above-mentioned heterogeneous catalyst preparation process, the chloromethylstyrene resin is spherical and has a particle size of 1.0 mm.
[0081] Preparation of methyl phenylcarbamate: 4.65 g (0.05 mol) of aniline, 36 g (0.4 mol) of dimethyl carbonate and 9.6 g of heterogeneous catalyst C8 were placed in a 100 mL autoclave and reacted at a temperature of 100° C. for 6 h, wherein the molar ratio of dimethyl carbonate to aniline was 8:1, and the mass ratio of heterogeneous catalyst C8 to dimethyl carbonate was 0.27:1. After the reaction, the autoclave was cooled to room temperature and vented; the liquid product was taken for gas chromatography analysis and calculated, and the conversion rate of aniline was 99.5%, and the selectivity of methyl phenylcarbamate was 97.8%.
[0082] Example 9
[0083] This embodiment provides a method for synthesizing methyl phenylcarbamate:
[0084] Preparation of heterogeneous catalyst for synthesizing methyl phenylcarbamate: In a 500 ml three-necked flask, add 50 g of chloromethylstyrene resin and 300 ml (284.4 g) of N,N-dimethylformamide, stir at 800 rpm for 2 h, heat to 70° C., add 30 g of imidazole, keep warm for 15 h, cool and separate the product, wash with deionized water, and dry the product at 120° C. for 24 h to obtain the improved catalyst. then in another 500ml three-necked flask, add 20g of modified resin, 0.14g of zinc nitrate and water to prepare a 100g solution, stir at 50°C at a rate of 600 rpm for 2h, put into an oven at 100°C for drying for 24h, transfer to a muffle furnace, and calcine at 500°C for 4h under a nitrogen atmosphere to obtain a heterogeneous catalyst C9, the mass percentage of zinc in C9 is 3.0%.
[0085] In the above-mentioned heterogeneous catalyst preparation process, the chloromethylstyrene resin is spherical and has a particle size of 1.0 mm.
[0086] Preparation of methyl phenylcarbamate: 4.65 g (0.05 mol) of aniline, 36 g (0.4 mol) of dimethyl carbonate and 5.8 g of heterogeneous catalyst C9 were placed in a 100 mL autoclave and reacted at a temperature of 160° C. for 5 h, wherein the molar ratio of dimethyl carbonate to aniline was 8:1, and the mass ratio of heterogeneous catalyst C9 to dimethyl carbonate was 0.16:1. After the reaction, the autoclave was cooled to room temperature and vented; the liquid product was taken for gas chromatography analysis and calculated, and the conversion rate of aniline was 99.7%, and the selectivity of methyl phenylcarbamate was 95.6%.
[0087] Example 10
[0088] This embodiment provides a method for synthesizing methyl phenylcarbamate:
[0089] Preparation of heterogeneous catalyst for synthesizing methyl phenylcarbamate: In a 500 ml three-necked flask, add 50 g of chloromethylstyrene resin and 300 ml (284.4 g) of N,N-dimethylformamide, stir at 800 rpm for 2 h, heat to 70° C., add 30 g of 1-methylimidazole, keep the temperature for 15 h, cool and separate the product, wash with deionized water, and dry the product at 120° C. for 24 h to obtain Modified resin; then in another 500ml three-necked flask, add 20g of modified resin, 0.23g of zinc nitrate and water to prepare a 100g solution, stir at 50°C at a rate of 600 rpm for 2h, put into an oven at 100°C for drying for 24h, transfer to a muffle furnace, and calcine at 500°C for 4h under a nitrogen atmosphere to obtain a heterogeneous catalyst C10, the mass percentage of zinc in C10 is 5.0%.
[0090] In the above-mentioned heterogeneous catalyst preparation process, the chloromethylstyrene resin is spherical and has a particle size of 1.0 mm.
[0091] Preparation of methyl phenylcarbamate: 4.65 g (0.05 mol) of aniline, 36 g (0.8 mol) of dimethyl carbonate and 9.6 g of heterogeneous catalyst C10 were placed in a 100 mL autoclave and reacted at 140° C. for 3 h, wherein the molar ratio of dimethyl carbonate to aniline was 8:1, and the mass ratio of heterogeneous catalyst C10 to dimethyl carbonate was 0.27:1. After the reaction, the autoclave was cooled to room temperature and vented; the liquid product was taken for gas chromatography analysis and calculated, and the conversion rate of aniline was 99.6%, and the selectivity of methyl phenylcarbamate was 94.4%.
[0092] Embodiment 11
[0093] This embodiment provides a method for synthesizing methyl phenylcarbamate:
[0094] Preparation of heterogeneous catalyst for synthesizing methyl phenylcarbamate: In a 500 ml three-necked flask, add 50 g of chloromethylstyrene resin and 300 ml (284.4 g) of N,N-dimethylformamide, stir at 800 rpm for 2 h, heat to 70° C., add 30 g of 1-methylimidazole, keep the temperature for 15 h, cool and separate the product, wash with deionized water, and dry the product at 120° C. for 24 h to obtain Modified resin; then in another 500ml three-necked flask, add 20g of modified resin, 0.33g of zinc acetate and water to prepare 100g of solution, stir at 500 rpm at 50°C for 2h, put into an oven at 100°C for drying for 24h, transfer to a muffle furnace, and calcine at 500°C for 4h under a nitrogen atmosphere to obtain a heterogeneous catalyst C11, the mass percentage of zinc in C11 is 7.0%.
[0095] In the above-mentioned heterogeneous catalyst preparation process, the chloromethylstyrene resin is spherical and has a particle size of 1.0 mm.
[0096] Preparation of methyl phenylcarbamate: 4.65 g (0.05 mol) of aniline, 36 g (0.4 mol) of dimethyl carbonate and 11.5 g of heterogeneous catalyst C11 were placed in a 100 mL autoclave and reacted at 120° C. for 4 h, wherein the molar ratio of dimethyl carbonate to aniline was 8:1, and the mass ratio of heterogeneous catalyst C11 to dimethyl carbonate was 0.3:1. After the reaction, the autoclave was cooled to room temperature and vented; the liquid product was taken for gas chromatography analysis and calculated, and the conversion rate of aniline was 99.6%, and the selectivity of methyl phenylcarbamate was 95.8%.
[0097] Example 12
[0098] This embodiment provides a method for synthesizing methyl phenylcarbamate:
[0099] Preparation of heterogeneous catalyst for synthesizing methyl phenylcarbamate: In a 500 ml three-necked flask, add 50 g of chloromethylstyrene resin and 200 ml (189.6 g) of N,N-dimethylformamide, stir at 500 rpm for 2 h, heat to 90°C, add 50 g of imidazole, keep warm for 12 h, cool and separate the product, wash with deionized water, and dry the product at 100°C for 24 h to obtain modified Resin; then in another 500ml three-necked flask, add 20g of modified resin, 0.073g of bismuth nitrate and water to prepare 60g of solution, stir at 50°C at 600 rpm for 8h, put into an oven at 100°C for drying for 24h, transfer to a muffle furnace, and calcine at 400°C for 8h under a nitrogen atmosphere to obtain a heterogeneous catalyst C12, the mass percentage of bismuth in C12 is 1.0%.
[0100] In the above-mentioned heterogeneous catalyst preparation process, the chloromethylstyrene resin is spherical and has a particle size of 0.9 mm.
[0101] Preparation of methyl phenylcarbamate: 4.65 g (0.05 mol) of aniline, 36 g (0.4 mol) of dimethyl carbonate and 1.9 g of heterogeneous catalyst C12 were placed in a 100 mL autoclave and reacted at a temperature of 170° C. for 8 h, wherein the molar ratio of dimethyl carbonate to aniline was 8:1, and the mass ratio of heterogeneous catalyst C12 to dimethyl carbonate was 0.05:1. After the reaction, the autoclave was cooled to room temperature and vented; the liquid product was taken for gas chromatography analysis and calculated, and the conversion rate of aniline was 99.5%, and the selectivity of methyl phenylcarbamate was 95.6%.
[0102] After the reaction is completed, the heterogeneous catalyst in the reaction liquid is filtered and recovered, washed with deionized water, placed in an oven for drying at 100° C. for 24 hours, and then reused, which is consistent with the conditions of the above-mentioned preparation process of methyl phenylcarbamate. After the reaction, the liquid phase product is taken for gas chromatography analysis and the aniline conversion rate is calculated. The heterogeneous catalyst is recycled and reused 5 times, and the conversion rate of aniline is greater than 99%, and the selectivity of methyl phenylcarbamate is greater than 95%.
[0103] Comparative Example 1
[0104] This comparative example provides a method for synthesizing methyl phenylcarbamate:
[0105] Preparation of heterogeneous catalyst for synthesizing methyl phenylcarbamate: In a 500ml three-necked flask, add 20g of chloromethylstyrene resin, 0.073g of bismuth nitrate and water to prepare a 50g solution, stir at 500 rpm for 6h at 30°C, put into an oven at 100°C for drying for 24h, transfer to a muffle furnace, and roast at 500°C for 5h under a nitrogen atmosphere to obtain heterogeneous catalyst S1, the mass percentage of bismuth in S1 is 1.0%. The scanning electron microscope image of heterogeneous catalyst S1 is shown in the figure below: Figure 2 The transmission electron microscope image of S1 is shown in Figure 5 As shown, the XRD pattern of S1 is Figure 3 As shown, Figure 3 The XRD curve representing C1 is located below the XRD curve representing S1.
[0106] In the above-mentioned heterogeneous catalyst preparation process, the chloromethylstyrene resin is spherical with a particle size of 0.5 mm. Preparation of methyl phenylcarbamate: 4.65 g (0.05 mol) of aniline, 45 g (0.5 mol) of dimethyl carbonate and 4.8 g of heterogeneous catalyst S1 are placed in a 100 mL autoclave and reacted at a temperature of 170°C for 3 hours, wherein the molar ratio of dimethyl carbonate to aniline is 10:1, and the mass ratio of heterogeneous catalyst S1 to dimethyl carbonate is 0.1:1. After the reaction is completed, the autoclave is cooled to room temperature and vented; the liquid phase product is taken for gas chromatography analysis and calculated, and the conversion rate of aniline is 39.4%, and the selectivity of methyl phenylcarbamate is 95.4%.
[0107] Comparative Example 2
[0108] This comparative example provides a method for synthesizing methyl phenylcarbamate:
[0109] Preparation of a heterogeneous catalyst for synthesizing methyl phenylcarbamate: 500 g of bismuth nitrate was calcined at 600° C. for 4 h under a nitrogen atmosphere to obtain a powder, which was tableted to obtain a columnar heterogeneous catalyst S2.
[0110] Preparation of methyl phenylcarbamate: 4.65 g (0.05 mol) of aniline, 45 g (0.5 mol) of dimethyl carbonate and 4.8 g of heterogeneous catalyst S2 were placed in a 100 mL autoclave and reacted at 170° C. for 3 h, wherein the molar ratio of dimethyl carbonate to aniline was 10:1, and the mass ratio of heterogeneous catalyst S2 to dimethyl carbonate was 0.1:1. After the reaction, the autoclave was cooled to room temperature and vented; the liquid product was taken for gas chromatography analysis and calculated, and the conversion rate of aniline was 7.4%, and the selectivity of methyl phenylcarbamate was 92.1%.
[0111] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.
Claims
1. A method for preparing a heterogeneous catalyst for synthesizing methyl phenylcarbamate, characterized in that: The preparation method comprises the step of using a carrier to load an active component; the carrier is carbon, and the active component is zinc and / or bismuth.
2. The preparation method according to claim 1, characterized in that: The carbon is obtained by carbonizing a modified chloromethyl resin; when preparing the modified chloromethyl resin, the chloromethyl resin is mixed with a solvent, a modifier is added, and the modified chloromethyl resin is obtained by modification; the modifier is a nitrogen-containing five-membered or six-membered heterocyclic aromatic compound; preferably, the modified chloromethyl resin is a modified chloromethyl styrene resin or a modified chloromethyl carboxylic acid resin.
3. The preparation method according to claim 1 or 2, characterized in that: The chloromethyl resin is a styrene-based or carboxylic acid-based resin; the particle size of the chloromethyl resin is 0.1 mm to 3 mm, preferably 0.3 mm to 2 mm; preferably, the chloromethyl resin is spherical; and / or, the modifier is at least one of piperazine, imidazole and pyridine; and / or, the solvent is at least one of toluene, methanol, ethanol, n-propanol, n-butanol, isobutanol or tert-butanol, tetrahydrofuran, dichloromethane, chloroform, N,N-dimethylformamide, ether and water; And / or, the mass ratio of the chloromethyl resin to the solvent is 1:(1-10), preferably 1:(2-8); And / or, the mass ratio of the chloromethyl resin to the modifier is 1:(0.1-1.2), preferably 1:(0.15-1); And / or, before adding the modifier, a stirring and heating step is included; the stirring rate is 50 rpm to 1000 rpm, preferably 100 rpm to 800 rpm; the stirring time is 1h to 24h, preferably 2h to 18h; the temperature after heating is 30°C to 150°C, preferably 40°C to 120°C; and / or, the modification time is 1 h to 24 h, preferably 2 h to 18 h; And / or, after the modification, the process further comprises the steps of cooling, separating, washing the product, and drying the product; preferably, the drying temperature is 80° C. to 180° C., and the drying time is 1 hour to 48 hours.
4. The preparation method according to any one of claims 1 to 3, characterized in that When the carrier is used to load the active component, the carrier is mixed with a metal precursor solution containing the active component, dried, and then calcined in an inactive gas atmosphere to obtain the heterogeneous catalyst.
5. The preparation method according to any one of claims 1 to 4, characterized in that: The metal precursor solution containing active components is at least one of nitrate solution, chloride solution and sulfate solution of zinc and / or bismuth, and the mass concentration of the metal precursor solution containing active components is 0.05% to 3%.
6. The preparation method according to any one of claims 1 to 5, characterized in that: When the carrier is used to load the active component, the mass ratio of the metal precursor containing the active component to the carrier is 1:(1-10), 1:(2-5); And / or, after the carrier is mixed with the metal precursor solution containing the active component, a heating and stirring step is further included, wherein the heating temperature is 20° C. to 100° C., the stirring rate is 100 rpm to 800 rpm, and the stirring time is 0.5 h to 10 h; And or, the drying temperature is 80°C to 180°C, and the drying time is 1h to 48h; and / or, the inert gas is nitrogen or argon; And / or, the calcination temperature is 200°C to 1000°C, preferably 250°C to 800°C, and the calcination time is 1h to 48h, preferably 2h to 24h.
7. A heterogeneous catalyst for synthesizing methyl phenylcarbamate prepared by the preparation method according to any one of claims 1 to 6, comprising a carrier and an active component, wherein the mass percentages of the carrier and the active component in the heterogeneous catalyst are: 90.0% to 99.9% of the carrier and 0.1% to 10.0% of the active component.
8. The preparation method according to claim 7, characterized in that: The particle size of the heterogeneous catalyst is 0.1 mm to 3 mm, preferably 0.3 mm to 2 mm.
9. A method for synthesizing methyl phenylcarbamate, characterized in that: The method comprises the step of reacting aniline and dimethyl carbonate under the action of a heterogeneous catalyst to obtain methyl phenylcarbamate; the heterogeneous catalyst is a heterogeneous catalyst for synthesizing methyl phenylcarbamate prepared by the preparation method according to any one of claims 1 to 6, or a heterogeneous catalyst for synthesizing methyl phenylcarbamate according to claim 7 or 8.
10. The synthesis method according to claim 9, characterized in that The reaction is carried out in an intermittent reactor, preferably, the reaction temperature is 80°C to 200°C, and the reaction time is 2h to 8h; And / or, the molar ratio of aniline to dimethyl carbonate is 1:(1-15), preferably 1:(2-10); And / or, the mass ratio of the heterogeneous catalyst to dimethyl carbonate is 1:1-20.