Mixed solid catalysts and their use in the preparation of p-aminophenyl alkyl ethers

Abstract

The application discloses a mixed solid catalyst and application thereof in preparation of p-aminophenyl alkyl ether, wherein the mixed solid catalyst is composed of an activated carbon supported noble metal catalyst and a perfluorosulfonic acid resin with a mass ratio of 1:1-10, and the activated carbon supported noble metal catalyst is one or more than two of Pt / C, Pd / C and Ir / C; the mixed solid catalyst system prepared according to the application realizes continuous reaction and synthesis of p-aminophenyl alkyl ether by using nitrobenzene and an alcohol solution as raw materials, and has its own unique advantages.

Description

Technical Field

[0001] This invention relates to a mixed solid catalyst and a continuous reaction process for synthesizing p-aminoanisole (p-aminophenethyl ether) in one step using nitrobenzene and methanol (ethanol) as raw materials and a solid combined catalyst. Background Technology

[0002] p-Aminoaniline, also known as p-methoxyaniline, is an important intermediate in the synthesis of pharmaceuticals, fragrances, and dyes. It can be used to produce drugs such as quinacrine and primaquine, as well as nearly 20 kinds of dyes, including ice dyes, vat dyes, and reactive dyes. p-Aminophene, also known as p-ethoxyaniline, is an important intermediate in the synthesis of pharmaceuticals, dyes, food preservatives, antioxidants, and rubber aging agents.

[0003] Currently, the main process routes for synthesizing p-aminophenoxymethyl ether and p-aminophenethyl ether include iron powder reduction, sodium sulfide reduction, and catalytic hydrogenation. Compared with iron powder reduction and sodium sulfide reduction, catalytic hydrogenation has significant advantages in terms of environmental protection and aligns with future development trends. However, the starting materials and reaction routes for synthesizing p-aminophenoxymethyl ether (p-aminophenoxymethyl ether) using catalytic hydrogenation vary. For example, in CN101307003 (Process for preparing aminophenoxymethyl ether and aniline from a mixture of nitrobenzeneethyl ether and nitrobenzene as raw materials), nitrobenzeneethyl ether and nitrobenzene are used as starting materials, ethanol is used as solvent, and Pd / C or Pt / C is used as hydrogenation catalyst. The catalytic hydrogenation reaction is carried out in a batch reactor, and after the reaction, p-aminophenoxymethyl ether is obtained by filtration, separation, and distillation. In CN110734383 (A Green Synthesis Method for p-Aminophene Ether), p-nitrophene ether is used as the starting material, and a nickel-based catalyst is used as the hydrogenation catalyst. The solvent-free catalytic hydrogenation reaction is carried out in a batch reactor. After the reaction, p-aminophene ether is obtained by filtration and distillation. However, the above process route generally has the following disadvantages: (1) The molecular structure of the starting material is complex, and the raw material cost is high; (2) The process route is long, generally requiring more than two chemical reactions and more than three post-processing steps, resulting in high production costs; (3) The above processes are all batch reactions carried out in batch reactors, resulting in low production efficiency, high safety risks, and high labor intensity.

[0004] In CN107417541 (Preparation process of p-aminophenethyl ether and aniline), nitrobenzene and ethanol are used as starting materials, excess ethanol is used as solvent, Pt / C is used as hydrogenation catalyst, and sulfuric acid is used as acid catalyst. The catalytic hydrogenation reaction is carried out in a batch reactor. After the reaction, ammonia water is introduced to neutralize the solution, followed by filtration, separation, and distillation to obtain p-aminophenethyl ether. In CN114621104 (Preparation of p-aminophenethyl ether), nitrobenzene and ethanol are used as starting materials, excess ethanol is used as solvent, Pt / C is used as hydrogenation catalyst, and sulfuric acid is used as acid catalyst. The catalytic hydrogenation reaction is carried out in a batch reactor. After the reaction, liquid ammonia is introduced to neutralize the solution, followed by filtration and distillation to obtain p-aminophenethyl ether. In the above process route, nitrobenzene is used as the starting material, and ethanol is used as both the raw material and the solvent. First, nitrobenzene undergoes incomplete hydrogenation under the action of a hydrogenation catalyst to obtain hydroxyaniline. Hydroxyaniline then undergoes a Bamberger rearrangement reaction with ethanol under the action of an acid catalyst to obtain p-aminophenethyl ether (the reaction mechanism is shown in the figure below). However, this process route still has two disadvantages: (1) Sulfuric acid is used as an acid catalyst, and a large amount of acidic wastewater is generated after the reaction, which needs to be treated. The recovery cost of ammonium sulfate formed after neutralization with ammonia water is high; (2) The use of sulfuric acid will cause serious equipment corrosion problems and high safety risks.

[0005]

[0006] Based on the above background, this invention proposes a continuous reaction process for synthesizing p-aminoanisole (p-aminophenethyl ether) in one step using nitrobenzene and ethanol (methanol) as starting materials and a solid combined catalyst. Summary of the Invention

[0007] The present invention provides a process route for the continuous reaction synthesis of p-aminophenethyl ether (p-aminophenmethyl ether) using nitrobenzene and ethanol (methanol) as raw materials.

[0008] The present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a mixed solid catalyst, wherein the mixed solid catalyst is composed of an activated carbon-supported noble metal catalyst and a perfluorosulfonic acid resin in a mass ratio of 1:1 to 10 (preferably 1:5), wherein the activated carbon-supported noble metal catalyst is one or more of Pt / C, Pd / C, and Ir / C (preferably Ir / C).

[0010] Preferably, the loading of noble metals in the activated carbon-supported noble metal catalyst is 0.5% to 3% (preferably 1%).

[0011] Furthermore, the activated carbon-supported noble metal catalyst is prepared by the following method: activating carbon is impregnated in an aqueous solution of a noble metal salt for 12 hours, the resulting impregnation solution is dried (in one embodiment of the present invention, vacuum drying at 50°C for 6 hours), and the resulting solid is reduced at 300°C for 2 hours in a hydrogen atmosphere to obtain the activated carbon-supported noble metal catalyst; the noble metal salt in the aqueous solution of the noble metal salt is one or more of chloroplatinic acid, chloroiridium acid, or chloropalladium acid; the loading amount is 0.5-3% (preferably 1%), calculated as the percentage of the mass of the noble metal element in the aqueous solution of the noble metal salt to the mass of the activated carbon.

[0012] Furthermore, the activated carbon has a particle size of 60-100 mesh.

[0013] Secondly, the present invention provides the application of the above-mentioned mixed solid catalyst in the preparation of p-aminophenylalkyl ethers.

[0014] In embodiments of the present invention, the p-aminophenylalkyl ether is p-aminoanisole or p-aminophenethyl ether.

[0015] Further, the application involves: loading the mixed solid catalyst into a fixed-bed reactor, using a mixture of hydrogen and nitrogen at a volume ratio of 0.25–3:1 (preferably 0.5–2:1) as the reaction gas, and a nitrobenzene alcohol solution with a mass fraction of 1–10% (preferably 6%) as the raw material, and conducting a continuous reaction at 0.1–2 MPa (preferably 1.2 MPa) and 50–110°C (preferably 70–80°C) to prepare p-aminophenylalkyl ether; the mass of the mixed solid catalyst, based on the effective reaction volume (volume of the isothermal zone) of the fixed-bed reactor, is 0.14–0.2 g / cm³. 3 .

[0016] Furthermore, the solvent for the nitrobenzene alcohol solution is methanol or ethanol.

[0017] Furthermore, the flow rate of the reaction gas into the fixed-bed reactor is 80 mL / min, and the flow rate of the raw material into the fixed-bed reactor is 0.5–10 mL / min (preferably 4–6 mL / min).

[0018] This hybrid solid catalyst system is composed of a supported hydrogenation catalyst and a solid acid catalyst. In a fixed-bed reactor, nitrobenzene and ethanol (methanol) react continuously under the action of the hybrid solid catalyst system to synthesize p-aminophenethyl ether (p-aminoanisole).

[0019] Furthermore, the preferred method for the continuous reaction synthesis of p-aminophenethyl ether (p-aminoanisole) is as follows: 20-30g of the mixed solid catalyst system is loaded into a fixed-bed reactor (inner diameter 4.5cm, total height 35cm, including a 9cm height in the isothermal zone); a 1-10% (mass percentage concentration) nitrobenzene-ethanol (methanol) solution is introduced into the fixed-bed reactor at a flow rate of 0.5-10ml / min; and hydrogen-nitrogen (V... H2 :V N2 The mixture (ratio 0.25–3:1) was introduced into a fixed-bed reactor at a flow rate of 80 ml / min. The reaction was carried out continuously at 50–110 °C under a mixed gas pressure of 0.1–2 MPa. The products were collected by condensation. The conversion rate of nitrobenzene and the selectivity of p-aminophenethyl ether (p-aminophenmethyl ether) were analyzed by gas chromatography.

[0020] Compared with the prior art, the present invention has the following beneficial effects: The mixed solid catalyst system formulated in this invention realizes the continuous synthesis of p-aminophenethyl ether (p-aminoanisole) from nitrobenzene and ethanol (methanol) as raw materials, and has its own unique advantages: 1) Compared with other catalyst systems, the reaction is carried out continuously in a fixed-bed reactor, which significantly improves the reaction efficiency and reduces safety risks and reaction costs; 2) Compared with the sulfuric acid catalysts in CN107417541 and CN114621104, the perfluorosulfonic acid resin catalyst does not corrode the reactor during the reaction and does not produce a large amount of acidic wastewater and waste salt, which has obvious advantages in terms of waste discharge and usage costs; 3) Compared with other catalyst systems, the post-reaction treatment is simplified from three steps of neutralization-filtration-distillation to one step of distillation. At the same time, thanks to the high catalytic activity and selectivity of the mixed solid catalyst system, the difficulty of distillation operation is reduced, which has obvious advantages in terms of post-reaction treatment costs. Attached Figure Description

[0021] Figure 1 For a fixed-bed reactor: 1, 17 - Filter; 2, 15 - Gas flow meter; 3 - Mixer; 4, 5, 16 - Check valve; 6 - High-pressure constant flow pump; 7 - Raw material storage tank; 8 - Tail gas valve; 9 - Reaction liquid inlet; 10 - Reaction liquid storage tank; 11 - Gas-liquid separator; 12 - Back pressure valve; 13 - Reactor; 14 - Heating furnace; 19 - High-purity nitrogen cylinder; 20 - High-purity hydrogen cylinder; 18, 21 - Pressure controller Detailed Implementation

[0022] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0023] Examples 1-3

[0024] Examples compare the effects of different noble metal-supported activated carbon catalysts on the synthesis performance of p-aminophenethyl ether. The preparation methods for different noble metal-supported activated carbon catalysts are as follows: 5g of activated carbon (Fujian Xinsen Carbon Industry Co., Ltd.) with a particle size of 60-100 mesh was immersed in 10ml of a chloroplatinic acid aqueous solution with a platinum concentration of 0.005g / ml. After impregnation at room temperature for 12h, it was vacuum dried at 50℃ for 6h, and then reduced in a hydrogen atmosphere at 300℃ for 2h to obtain a Pt / C catalyst with a platinum loading of 1%. Pd / C and Ir / C catalysts with the same metal loading were prepared using the same method, the only difference being that chloropalladium acid or chloroiridium acid was used instead of chloroplatinic acid.

[0025] 5g of the above-mentioned noble metal supported activated carbon catalysts and 20g of perfluorosulfonic acid resin (Jiangyin Nanda Synthetic Chemical Co., Ltd.) were uniformly mixed and then loaded into a fixed-bed reactor. A 5% (w / w) nitrobenzene-ethanol solution was introduced into the reactor at a flow rate of 2ml / min, while a hydrogen-nitrogen mixture (V) was simultaneously introduced. H2 V N2 A mixture of 1:1 (nitrobenzene, p-aminophenethyl ether) was introduced into the reactor at a flow rate of 80 ml / min and reacted at 90 °C under a mixed gas pressure of 1 MPa. The product was collected by condensation, and the conversion rate of nitrobenzene and the selectivity of p-aminophenethyl ether were obtained by gas chromatography analysis. Samples were taken and analyzed after 8 hours of reaction, as shown in the table below.

[0026]

[0027] Examples 4-7

[0028] Examples compare the effect of metal loading on the performance of Ir / C catalysts in the synthesis of aminophene ether. The preparation methods for Ir / C catalysts with different metal loadings are as follows: 5g of activated carbon support with a particle size of 60-100 mesh was immersed in different volumes of aqueous chloroiridium acid solution with an iridium mass concentration of 0.005g / ml. After impregnation at room temperature for 12h, the solution was vacuum dried at 50℃ for 6h, and then reduced in a hydrogen atmosphere at 300℃ for 2h to obtain Ir / C catalysts with different loadings.

[0029] 5g of Ir / C catalyst with different loadings was uniformly mixed with 20g of perfluorosulfonic acid resin and then loaded into a fixed-bed reactor. A 5% (w / w) nitrobenzene-ethanol solution was introduced into the reactor at a flow rate of 2ml / min, while a hydrogen-nitrogen mixture (V0.05) was introduced. H2 V N2 A mixture of 1:1 (nitrobenzene, p-aminophenethyl ether) was introduced into the reactor at a flow rate of 80 ml / min and reacted at 90 °C under a mixed gas pressure of 1 MPa. The product was collected by condensation, and the conversion rate of nitrobenzene and the selectivity of p-aminophenethyl ether were obtained by gas chromatography analysis. Samples were taken and analyzed after 8 hours of reaction, as shown in the table below.

[0030]

[0031]

[0032] Examples 8-12

[0033] The examples compared the effect of the mass ratio of Ir / C catalyst to perfluorosulfonic acid resin on the performance of the synthesis of p-aminophenethyl ether. The iridium loading was 1%, and the preparation method of the Ir / C catalyst was the same as in Example 3. The Ir / C catalysts of different masses were uniformly mixed with perfluorosulfonic acid resin and then loaded into a fixed-bed reactor. A 5% (w / w) nitrobenzene-ethanol solution was introduced into the reactor at a flow rate of 2 ml / min, while a hydrogen-nitrogen mixture (V2) was simultaneously introduced. H2 V N2 A mixture of 1:1 (nitrobenzene, p-aminophenethyl ether) was introduced into the reactor at a flow rate of 80 ml / min and reacted at 90 °C under a mixed gas pressure of 1 MPa. The product was collected by condensation, and the conversion rate of nitrobenzene and the selectivity of p-aminophenethyl ether were obtained by gas chromatography analysis. Samples were taken and analyzed after 8 hours of reaction, as shown in the table below.

[0034]

[0035] Examples 13-18

[0036] The examples compared the effect of reaction temperature on the performance of the synthesis of p-aminophenethyl ether. The iridium loading was 1%, and the preparation method of the Ir / C catalyst was the same as in Example 3. 4g of Ir / C catalyst was uniformly mixed with 20g of perfluorosulfonic acid resin and then loaded into a fixed-bed reactor. A 5% (w / w) nitrobenzene-ethanol solution was introduced into the reactor at a flow rate of 2ml / min, while a hydrogen-nitrogen mixture (V2) was simultaneously introduced. H2 V N2 A mixture of 1:1 (nitrobenzene, p-aminophenethyl ether) was introduced into the reactor at a flow rate of 80 ml / min and reacted at different temperatures under a mixed gas pressure of 1 MPa. The products were collected by condensation, and the conversion rate of nitrobenzene and the selectivity of p-aminophenethyl ether were obtained by gas chromatography analysis. Samples were taken and analyzed after 8 hours of reaction, as shown in the table below.

[0037]

[0038]

[0039] Examples 19-24

[0040] The examples compared the effect of reaction pressure on the performance of the synthesis of p-aminophenethyl ether. The iridium loading was 1%, and the Ir / C catalyst was prepared using the same method as in Example 3. 4g of Ir / C catalyst was uniformly mixed with 20g of perfluorosulfonic acid resin and then loaded into a fixed-bed reactor. A 5% (w / w) nitrobenzene-ethanol solution was introduced into the reactor at a flow rate of 2ml / min, while a hydrogen-nitrogen mixture (V0.05) was simultaneously introduced.H2 V N2 A mixture of 1:1 gas was introduced into the reactor at a flow rate of 80 ml / min, and the reaction was carried out at 80 °C under different mixed gas pressures. The products were collected by condensation, and the conversion rate of nitrobenzene and the selectivity of p-aminophenethyl ether were obtained by gas chromatography analysis. Samples were taken and analyzed after 8 hours of reaction, as shown in the table below.

[0041]

[0042] Examples 25-28

[0043] The examples compared the effect of the reaction mixture ratio on the performance of the synthesis of p-aminophenethyl ether. The iridium loading was 1%, and the Ir / C catalyst was prepared using the same method as in Example 3. 4g of Ir / C catalyst was uniformly mixed with 20g of perfluorosulfonic acid resin and then loaded into a fixed-bed reactor. A 5% (w / w) nitrobenzene-ethanol solution was introduced into the reactor at a flow rate of 2 ml / min. Simultaneously, hydrogen-nitrogen mixtures of different proportions were introduced into the reactor at a flow rate of 80 ml / min. The reaction was carried out at 80°C under a mixed gas pressure of 1 MPa. The product was collected by condensation, and the nitrobenzene conversion and p-aminophenethyl ether selectivity were obtained by gas chromatography analysis. Samples were taken and analyzed after 8 hours of reaction, as shown in the table below.

[0044]

[0045] Examples 29-34

[0046] The examples compared the effect of nitrobenzene-ethanol solution concentration on the performance of the synthesis of p-aminophenethyl ether. The iridium loading was 1%, and the Ir / C catalyst was prepared using the same method as in Example 3. 4g of Ir / C catalyst was uniformly mixed with 20g of perfluorosulfonic acid resin and then loaded into a fixed-bed reactor. Nitrobenzene-ethanol solutions of different mass concentrations were introduced into the reactor at a flow rate of 2ml / min, while a hydrogen-nitrogen mixture (V2) was simultaneously introduced. H2 V N2 A mixture of 1:1 (nitrobenzene, p-aminophenethyl ether) was introduced into the reactor at a flow rate of 80 ml / min and reacted at 80 °C under a mixed gas pressure of 1 MPa. The product was collected by condensation, and the conversion rate of nitrobenzene and the selectivity of p-aminophenethyl ether were obtained by gas chromatography analysis. Samples were taken and analyzed after 8 hours of reaction, as shown in the table below.

[0047]

[0048] Examples 35-40

[0049] The examples compared the effect of nitrobenzene-ethanol solution flow rate on the performance of the synthesis of p-aminophenethyl ether. The iridium loading was 1%, and the Ir / C catalyst was prepared using the same method as in Example 3. 4g of Ir / C catalyst was uniformly mixed with 20g of perfluorosulfonic acid resin and then loaded into a fixed-bed reactor. A 6% (w / w) nitrobenzene-ethanol solution was introduced into the reactor at different flow rates, while a hydrogen-nitrogen mixture (V0.05) was simultaneously introduced. H2 V N2 A mixture of 1:1 (nitrobenzene, p-aminophenethyl ether) was introduced into the reactor at a flow rate of 80 ml / min and reacted at 80 °C under a mixed gas pressure of 1 MPa. The product was collected by condensation, and the conversion rate of nitrobenzene and the selectivity of p-aminophenethyl ether were obtained by gas chromatography analysis. Samples were taken and analyzed after 8 hours of reaction, as shown in the table below.

[0050]

[0051] Example 41

[0052] The examples compared the effect of reaction time on the performance of the synthesis of p-aminophenethyl ether. The iridium loading was 1%, and the preparation method of the Ir / C catalyst was the same as in Example 3. 4g of Ir / C catalyst was uniformly mixed with 20g of perfluorosulfonic acid resin and then loaded into a fixed-bed reactor. A 6% (w / w) nitrobenzene-ethanol solution was introduced into the reactor at a flow rate of 4ml / min, while a hydrogen-nitrogen mixture (V2) was simultaneously introduced. H2 V N2 A mixture of 1:1 (nitrobenzene, p-aminophenethyl ether) was introduced into the reactor at a flow rate of 80 ml / min and reacted at 80 °C under a mixed gas pressure of 1 MPa. The product was collected by condensation, and the conversion rate of nitrobenzene and the selectivity of p-aminophenethyl ether were obtained by gas chromatography analysis. Samples were taken every 10 hours after the reaction, as shown in the table below.

[0053]

[0054] Example 42

[0055] The examples compared the effect of nitrobenzene-methanol solution flow rate on the performance of the synthesis of p-aminoanisole. The iridium loading was 1%, and the Ir / C catalyst was prepared using the same method as in Example 3. 4g of Ir / C catalyst was uniformly mixed with 20g of perfluorosulfonic acid resin and then loaded into a fixed-bed reactor. A 6% (w / w) nitrobenzene-methanol solution was introduced into the reactor at different flow rates, while a hydrogen-nitrogen mixture (V0.05) was simultaneously introduced. H2 V N2 A mixture of 1:1 (nitrobenzene, p-aminoanisole, and nitrobenzene) was introduced into the reactor at a flow rate of 80 ml / min and reacted at 80 °C under a mixed gas pressure of 1 MPa. The product was collected by condensation, and the conversion rate of nitrobenzene and the selectivity of p-aminoanisole were obtained by gas chromatography. Samples were taken and analyzed after 8 hours of reaction, as shown in the table below.

[0056]

Claims

1. The application of a mixed solid catalyst in the preparation of p-aminophenylalkyl ethers, characterized in that: The mixed solid catalyst is composed of activated carbon-supported noble metal catalyst and perfluorosulfonic acid resin in a mass ratio of 1:1 to 10. The activated carbon-supported noble metal catalyst is one or more of Pt / C, Pd / C, and Ir / C. The application method is as follows: the mixed solid catalyst is loaded into a fixed-bed reactor, using a mixture of hydrogen and nitrogen at a volume ratio of 0.25~3:1 as the reactant gas, and a 1~10% (w / w) alcohol solution of nitrobenzene as the raw material, and the reaction is carried out continuously at 0.1~2 MPa and 50~110℃ to prepare p-aminophenylalkyl ether; the mass of the mixed solid catalyst is 0.14-0.2 g / cm³ based on the effective reaction volume of the fixed-bed reactor. 3 ; The solvent for the nitrobenzene alcohol solution is methanol or ethanol; the flow rate of the reaction gas into the fixed-bed reactor is 80 mL / min, and the flow rate of the raw material into the fixed-bed reactor is 0.5~10 mL / min.

2. The application as described in claim 1, characterized in that: The loading of precious metals in the activated carbon-supported precious metal catalyst is 0.5-3%.

3. The application as described in claim 2, characterized in that: The loading of precious metals in the activated carbon-supported precious metal catalyst is 1%.

4. The application as described in claim 1, characterized in that: The activated carbon-supported noble metal catalyst is Ir / C.

5. The application as described in claim 1, characterized in that: The hybrid solid catalyst is composed of activated carbon-supported noble metal catalyst and perfluorosulfonic acid resin in a mass ratio of 1:

5.

6. The application as described in claim 1, characterized in that: The p-aminophenylalkyl ether is p-aminoanisole or p-aminophenethyl ether.

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