Preparation method and application of catalyst for efficiently synthesizing p-aminophenol in CO2 / H2-water system

Abstract

The invention discloses a preparation method of a catalyst for efficiently synthesizing p-aminophenol in a CO2 / H2-water system, the catalyst takes noble metal Pt, Au, Pd, Rh or Ru as an active component and is loaded on sulfonic acid resin; comprising the following steps: (1) immersing sulfonic acid resin in absolute ethyl alcohol, soaking for 12-24 hours, then immersing in a ketone reagent, soaking for 12-24 hours, filtering and drying; (2) soaking the acid sulfonic acid resin in a 5-15 wt% diluted hydrochloric acid solution for 24 hours, filtering, washing to remove diluted hydrochloric acid, and drying at 80 DEG C for 24 hours to obtain treated acid sulfonic acid resin; and (3) weighing 20g of treated acidic sulfonic acid resin, adding 200mL of an ethanol solution of noble metal into the acidic sulfonic acid resin, stirring at 50 DEG C for 4 hours, filtering, washing twice with ethanol, and drying. Precious metal is loaded on treated acidic sulfonic acid resin to form a composite catalyst, and the composite catalyst is combined with a CO2 / H2-water system to promote two reaction processes of hydrogen transfer hydrogenolysis of nitro hydrogenation and Bamberger rearrangement of a phenylhydroxylamine intermediate.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of p-aminophenol, and specifically relates to a preparation method and application of a catalyst for efficiently synthesizing p-aminophenol in a CO2 / H2-water system. Background Art

[0002] p-Aminophenol is an important chemical raw material, which is widely used in the pharmaceutical industry and organic fine chemical field. For example, it can be used as an intermediate for the organic synthesis of paracetamol, clofibrate and other drugs, and can also be used in the dye industry to produce various fur dyes, acid dyes and oxidation dyes; in the rubber industry, p-aminophenol is mainly used for the synthesis of tire product antioxidants, and can also be used as a developer in the photography industry.

[0003] In industry, the methods for synthesizing p-aminophenol include p-nitrophenol reduction, phenol nitrosation, 4-hydroxyacetophenone oxime, Beckmann rearrangement, etc. Among them, nitrobenzene hydrogenation has attracted the attention of many researchers due to its simple process and low cost. Its preparation and synthesis process is as follows: nitrobenzene is hydrogenated to generate phenylhydroxylamine intermediate, and then Bamberger rearrangement is carried out under acidic conditions to obtain p-aminophenol. However, there is a competitive reaction in this process, that is, phenylhydroxylamine will be further hydrogenated to generate aniline by-product. This requires a catalyst with high catalytic activity and selectivity. Precious metals such as Pt, Au, Pd, Rh, and Ru are often used as active components of hydrogenation catalysts. Among them, the catalytic activity of Pt as an active component is higher than that of other metals, and it has higher selectivity and reaction rate. However, sulfuric acid with a high concentration is often used as an acid catalyst for the rearrangement of phenylhydroxylamine. Special corrosion-resistant materials are required during the reaction process. The large amount of sulfuric acid used causes many defects such as equipment corrosion and environmental pollution.

[0004] In recent years, there have been reports of catalysts that can replace traditional liquid acids, such as solid acid systems, solid acid-loaded transition metal dual-effect catalytic systems, acidic ionic liquid systems, Lewis acid systems, and carbon dioxide-water, which can replace traditional liquid acid systems for the preparation and synthesis of p-aminophenol. Among them, the carbon dioxide-water system is a green acidic solvent (CO2 + H2O ⇌ H2CO3 ⇌ H + + HCO3 -), after the reaction, the carbon dioxide is discharged in the form of gas through pressure relief and heating, which does not corrode the reaction equipment and simplifies the post-treatment process. This system is an environmentally friendly acidic catalytic system. At relevant temperature and pressure, the pH can be close to 2.80 (The promoting effects of CO2and H2O on selective hydrogenations in CO2 / H2O biphasic system. Current Opinion in Green and Sustainable Chemistry, 2018, 10:46-50.) It can replace the traditional hydrochloric acid / sulfuric acid system for green chemical synthesis. There are related literature reports that different systems of catalysts (such as Pd / C, Pd-CaCO3-PbO / PbAc2, Pt-Sn / Al2O3, Pt / Al2O3, etc.) have been developed to catalyze the hydrogenation and rearrangement of nitrobenzene to prepare p-aminophenol using a carbon dioxide-water system. However, most of the reported yield conversions are not high, or the selectivity is low, and cannot be used for industrial-scale production. It should be noted that if the phenylhydroxylamine intermediate is not rapidly further hydrogenated and rearranged, the selectivity of the product will be affected. This requires considering the catalytic hydrogenation process and the Bamberger rearrangement process carried out by acid catalysis at the same time. On the one hand, the ability of hydrogen transfer hydrogenolysis can be improved and the rearrangement conversion can be achieved rapidly. In the present invention, the composite catalyst supported by a precious metal on a sulfonic acid resin can better exert the effect of the reaction in a CO2 / H2-water system. Therefore, it is necessary to develop a novel catalyst and catalytic technology for the defects of the reaction process to form a green and environmentally friendly preparation and synthesis process, which can avoid strong acid as a medium reaction on the one hand, and can efficiently synthesize p-aminophenol. Summary of the invention

[0005] A method for preparing a catalyst for efficiently synthesizing p-aminophenol in a CO2 / H2-water system, wherein the catalyst uses precious metals such as Pt, Au, Pd, Rh or Ru as active components and is loaded on a sulfonic acid resin; The specific steps include: (1) Immerse the sulfonic acid resin in anhydrous ethanol for 12 to 24 hours, then immerse it in a ketone reagent for 12 to 24 hours, filter, and dry; (2) then immersing it in a 5-15 wt% dilute hydrochloric acid solution for 24 hours, filtering, washing to remove residual dilute hydrochloric acid, and drying at 80° C. for 24 hours to obtain a treated acidic sulfonic acid resin; (3) Weigh 20 g of the treated acidic sulfonic acid resin, add 200 mL of the ethanol solution of the noble metal thereto, stir at 50 °C for 4 h, filter, wash twice with ethanol, and dry to obtain a catalyst.

[0006] Preferably, the sulfonic acid resin in step (1) is D001, 732, Amberlite IR120 or Amberlyst-15.

[0007] Preferably, the noble metal is chloroauric acid, chloroplatinic acid, palladium nitrate, rhodium octanoate, or ruthenium nitrate; and the concentration of the noble metal ethanol solution is 0.005 mol / L to 0.02 mol / L.

[0008] A CO2 / H2-water system for efficiently synthesizing p-aminophenol comprises the following steps: loading a catalyst in a fixed bed reactor, using nitrobenzene, water and a zwitterionic compound as raw materials, ultrasonically mixing the raw materials as reactants, and transporting them to the reactor through a horizontal flow pump; using CO2 / H2 in a volume ratio of (3-20):1 as a reaction gas, and continuously reacting at a temperature of 80-100°C and a reaction pressure of 1-5 MPa to obtain p-aminophenol.

[0009] Preferably, the mass ratio of nitrobenzene, water and zwitterion is 1:(3-10):(0.0002-0.4).

[0010] Preferably, the zwitterion is tetrabutylammonium bromide, hexadecyltributylammonium bromide or a combination of the two.

[0011] Preferably, the CO2 / H2 volume ratio is 10:1, the reaction temperature is 80°C, and the reaction pressure is 4 MPa.

[0012] Preferably, the ratio of the amount of the catalyst added to the flow rate of the reactants is (10-2000):1.

[0013] Preferably, the ratio of the amount of the catalyst added to the flow rate of the reactants is 100:1.

[0014] Advantages of the present invention: 1) The acidic environment provided by the composite catalyst formed by loading the precious metal on the treated acidic sulfonic acid resin, combined with the CO2 / H2-water system, simultaneously promotes the two reaction processes of hydrogen transfer hydrogenolysis of nitro hydrogenation and Bamberger rearrangement of phenylhydroxylamine intermediate; 2) The reaction process of composite catalyst in CO2 / H2-water system using fixed bed continuous hydrogenation is more efficient, safer and more reliable than the traditional intermittent reactor reaction. The continuous hydrogenation catalyst can run for 7 days, and the activity and selectivity of the catalyst remain in a good state; 3) This process replaces the traditional sulfuric acid water system, avoids the use of large-scale sulfuric acid, is simple to post-process, is green and pollution-free, and demonstrates the development concept of green chemical industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is the NMR spectrum of the product of the catalyst application example in Example 1. DETAILED DESCRIPTION

[0016] Example 1 A method for preparing a catalyst for efficiently synthesizing p-aminophenol in a CO2 / H2-water system, wherein the catalyst uses precious metals Pt, Au, Pd, Rh or Ru as active components and is loaded on a sulfonic acid resin; The specific preparation method comprises the following steps: (1) Immerse Amberlyst-15 in anhydrous ethanol for 12 h, then immerse it in ketone for 18 h, filter, and dry; (2) then immersing it in a 10 wt % dilute hydrochloric acid solution for 24 h, filtering, washing to remove residual dilute hydrochloric acid, and drying at 80 ° C for 24 h to obtain a treated sulfonic acid resin; (3) Weigh 20 g of the treated sulfonic acid resin, add 200 mL of 0.005 mol / L chloroplatinic acid ethanol solution, stir at 50 °C for 4 h, filter, wash twice with ethanol, and dry to obtain a catalyst. Label it as S1.

[0017] Example 2 The chloroplatinic acid was replaced by chloroauric acid, and the rest was the same as in Example 1. It is marked as S2.

[0018] Example 3 Chloroplatinic acid was replaced by palladium nitrate, and the rest was the same as in Example 1. It is marked as S3.

[0019] Example 4 A method for preparing a catalyst for efficiently synthesizing p-aminophenol in a CO2 / H2-water system, wherein the catalyst uses precious metals Pt, Au, Pd, Rh or Ru as active components and is loaded on a sulfonic acid resin; The specific preparation method comprises the following steps: (1) Immerse Amberlite IR120 in anhydrous ethanol for 15 h, then immerse it in ketone for 24 h, filter and dry; (2) then immersing it in a 5 wt % dilute hydrochloric acid solution for 24 h, filtering, washing to remove residual dilute hydrochloric acid, and drying at 80 ° C for 24 h to obtain a treated sulfonic acid resin; (3) Weigh 20 g of the treated sulfonic acid resin, add 200 mL of 0.01 mol / L ruthenium nitrate ethanol solution, stir at 50 °C for 4 h, filter, wash twice with ethanol, and dry to obtain a catalyst, which is labeled S4.

[0020] Example 5 A method for preparing a catalyst for efficiently synthesizing p-aminophenol in a CO2 / H2-water system, wherein the catalyst uses precious metals Pt, Au, Pd, Rh or Ru as active components and is loaded on a sulfonic acid resin; The specific preparation method comprises the following steps: (1) Immerse D0010 in anhydrous ethanol for 24 hours, then immerse it in ketone for 12 hours, filter and dry; (2) then immersing it in a 15 wt % dilute hydrochloric acid solution for 24 h, filtering, washing to remove residual dilute hydrochloric acid, and drying at 80 ° C for 24 h to obtain a treated sulfonic acid resin; (3) Weigh 20 g of the treated sulfonic acid resin, add 200 mL of 0.02 mol / L octanoic acid rhodium ethanol solution, stir at 50 °C for 4 h, filter, wash twice with ethanol, and dry to obtain a catalyst. Labeled as S5.

[0021] Example 6 A method for preparing a catalyst for efficiently synthesizing p-aminophenol in a CO2 / H2-water system, wherein the catalyst uses precious metals Pt, Au, Pd, Rh or Ru as active components and is loaded on a sulfonic acid resin; The specific preparation method comprises the following steps: (1) Immerse 732 resin in anhydrous ethanol for 18 hours, then immerse in ketone for 24 hours, filter and dry; (2) then immersing it in an 8 wt % dilute hydrochloric acid solution for 24 h, filtering, washing to remove residual dilute hydrochloric acid, and drying at 80 ° C for 24 h to obtain a treated sulfonic acid resin; (3) Weigh 20 g of the treated sulfonic acid resin, add 200 mL of 0.02 mol / L chloroplatinic acid ethanol solution, stir at 50 °C for 4 h, filter, wash twice with ethanol, and dry to obtain a catalyst. Label it as S6.

[0022] Example 7 In order to investigate the life of the catalyst, the conditions remained unchanged and the same as in Example 1, p-aminophenol product was obtained by continuous hydrogenation for 7 days.

[0023] Comparative Example 1: The sulfonic acid resin was not treated, and the other parts were the same as those in Example 1. It is marked as S7 application A CO2 / H2-water system for efficiently synthesizing p-aminophenol comprises the following steps: loading a catalyst in a fixed bed reactor, weighing nitrobenzene, water and zwitterions in a mass ratio of 1:(3-10):(0.0002-0.4) as raw materials, ultrasonically mixing them as reactants, pumping them into the reactor, using CO2 / H2 in a volume ratio of (3-20):1 as reaction gas, reacting continuously at a temperature of 80-100°C and a reaction pressure of 1-5 MPa to obtain p-aminophenol; The zwitterion is tetrabutylammonium bromide, hexadecyltributylammonium bromide or a combination of the two; The ratio of the amount of the catalyst added (g) to the flow rate of the reactant (mL / min) is (10-2000):1; The catalysts prepared in Examples 1-6 and Comparative Example 1 were used to continuously produce p-aminophenol according to the method in the above application. The specific reaction parameters and reaction results are shown in Table 1.

[0024] The catalyst obtained in Example 1 was used in the CO2 / H2-water system to efficiently synthesize p-aminophenol. The conversion rate of the raw material reached 100%, and the selectivity of the product reached 98%. Figure 1 As shown: 1 H NMR (600 MHz, DMSO-D6) δ 8.36 (s, 1H), 6.50 – 6.46 (m, 2H), 6.45 – 6.39 (m, 2H), 4.54 (s, 2H).

Claims

1. A method for preparing a catalyst for efficiently synthesizing p-aminophenol in a CO2 / H2-water system, characterized in that: The catalyst uses precious metals such as Pt, Au, Pd, Rh or Ru as active components and is loaded on a sulfonic acid resin; The specific steps include: (1) Immerse the sulfonic acid resin in anhydrous ethanol for 12 to 24 hours, then immerse it in a ketone reagent for 12 to 24 hours, filter, and dry; (2) then immersing it in a 5-15 wt% dilute hydrochloric acid solution for 24 hours, filtering, washing to remove residual dilute hydrochloric acid, and drying at 80° C. for 24 hours to obtain a treated acidic sulfonic acid resin; (3) Weigh 20 g of the treated acidic sulfonic acid resin, add 200 mL of the ethanol solution of the noble metal thereto, stir at 50 °C for 4 h, filter, wash twice with ethanol, and dry to obtain a catalyst.

2. The method for preparing a catalyst for efficiently synthesizing p-aminophenol in a CO2 / H2-water system according to claim 1, characterized in that: In the step (1), the sulfonic acid resin is D001, 732, Amberlite IR120 or Amberlyst-15.

3. The method for preparing a catalyst for efficiently synthesizing p-aminophenol in a CO2 / H2-water system according to claim 1, characterized in that: The noble metals are chloroauric acid, chloroplatinic acid, palladium nitrate, rhodium octanoate, and ruthenium nitrate; and the concentration of the noble metal ethanol solution is 0.005 mol / L to 0.02 mol / L.

4. A CO2 / H2-water system for efficiently synthesizing p-aminophenol, characterized in that: In a fixed bed reactor, a catalyst is loaded, nitrobenzene, water and a zwitterionic compound are used as raw materials, the raw materials are ultrasonically mixed as reactants, and are transported to the reactor by a horizontal flow pump. CO2 / H2 volume ratio of (3 to 20) : 1 is used as the reaction gas, and continuous reaction is carried out at a temperature of 80 to 100°C and a reaction pressure of 1 to 5 MPa to obtain p-aminophenol, wherein the catalyst is the catalyst described in claim 1.

5. The CO2 / H2-water system for efficiently synthesizing p-aminophenol according to claim 4, characterized in that: The mass ratio of nitrobenzene, water and zwitterion is 1:(3-10):(0.0002-0.4).

6. The CO2 / H2-water system for efficiently synthesizing p-aminophenol according to claim 5, characterized in that: The zwitterion is tetrabutylammonium bromide, hexadecyltributylammonium bromide or a combination of the two.

7. The CO2 / H2-water system for efficiently synthesizing p-aminophenol according to claim 4, characterized in that: The CO2 / H2 volume ratio is 10:1, the reaction temperature is 80°C, and the reaction pressure is 4MPa.

8. The CO2 / H2-water system for efficiently synthesizing p-aminophenol according to claim 4, characterized in that: The ratio of the amount of the catalyst added to the flow rate of the reactants is (10-2000):

1.

9. The CO2 / H2-water system for efficiently synthesizing p-aminophenol according to claim 8, characterized in that: The ratio of the amount of the catalyst added to the flow rate of the reactants is 100:1.

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