Highly efficient and directional conversion of rifamycin B to O using an iron single-atom catalyst and its application

Abstract

The present invention discloses a kind of iron single atom catalyst and application thereof for efficient directional conversion of rifamycin B to O, and belongs to the field of environmental engineering, chemical engineering and materials engineering technology.The present invention regulates the iron single atom microenvironment by sulfur, and develops a catalyst for directional regulation of electron transfer path in rifamycin B to O conversion.For the regulation and control problem of specific functional group targeted dehydrogenation reaction path in rifamycin B to O conversion, the present invention accurately regulates electron transfer intensity and site by regulating sulfur-iron coordination mode and content, and finally realizes efficient directional conversion.The iron single atom catalyst prepared by this method can make the conversion yield of rifamycin B to O reach 91.35%, and product purity reaches 95%, which is better than existing technology.

Description

Technical Field

[0001] The present invention belongs to the technical fields of environmental engineering, chemical engineering and materials engineering, and in particular relates to an iron single-atom catalyst for efficiently and directionally converting rifamycin B to O and an application thereof. Background Art

[0002] Rifamycin antibiotics are first-line drugs in the treatment of tuberculosis. Their potent efficacy and broad antimicrobial activity play a crucial role in the fight against tuberculosis. Rifamycin B, the raw material for the synthesis of many rifamycin antibiotics, is highly water-soluble and toxic, making the high-concentration pharmaceutical wastewater it produces difficult to treat. Rifamycin O, a water-insoluble oxidation product of rifamycin B, has been widely used in the rifamycin pharmaceutical industry as an important synthetic intermediate (e.g., rifaximin). Achieving efficient, targeted conversion of rifamycin B to O can detoxify high-concentration rifamycin B pharmaceutical wastewater and recover rifamycin O at a high value, significantly impacting the pretreatment of high-concentration antibiotic wastewater and the development of rifamycin antibiotics.

[0003] Traditional methods that add oxidants (such as sodium persulfate) to promote the conversion of rifamycin B to O only achieve a mass yield of approximately 80%. However, the addition of a moderate amount of butyl acetate before the reaction can accelerate the conversion, achieving a mass yield of 85%. For a long time, further improvements in the mass yield of this conversion have been difficult due to complex matrix effects and the difficulty in controlling electron transfer in high-concentration pharmaceutical wastewater (COD > 60,000 mg / L). The glycolic acid carboxyl group and the naphthalene ring hydroxyl group in the rifamycin B molecule are chemically active. By designing a specific dehydrogenation reaction pathway and precisely controlling electron transfer between sodium persulfate (PDS) and the rifamycin B molecule, further improvements in mass yield are expected.

[0004] A sulfur (S)-coordinated iron single-atom catalyst was prepared by combining a wet chemical method with a hydrothermal process. The introduction of S modulates the microenvironment of the iron single atom, altering the catalyst's electrical conductivity and the adsorption structure between rifamycin B and the catalyst. This allows for the controlled transfer of electrons from rifamycin B to the catalyst and then to the oxidant, thereby regulating the intensity and site of action. This allows for directional regulation of the electron transfer process during the rifamycin B-to-O oxidation process, achieving efficient, targeted conversion while minimizing side reactions. This iron single-atom catalyst achieves a 91.35% rifamycin B-to-O conversion yield and 95% product purity, surpassing existing processes. Summary of the Invention

[0005] The purpose of the present invention is to address the deficiencies of the prior art and provide an iron single-atom catalyst for the efficient and directional conversion of rifamycin B to O and its application.

[0006] The object of the present invention is achieved through the following technical solutions:

[0007] In a first aspect, the present invention provides an iron single-atom catalyst for the efficient and directional conversion of rifamycin B to O, wherein the iron single-atom catalyst for the efficient and directional conversion of rifamycin B to O is prepared by the following steps:

[0008] 3.1-3.5 g of melamine was dissolved in 300-350 mL of deionized water at 80-95° C. to form solution a, 2.5-3.0 g of cyanuric acid was dissolved in 200-250 mL of deionized water at 80-95° C. to form solution b, 0.4-0.5 g of oxalic acid and 0.5-0.6 g of ferric nitrate nonahydrate were weighed and dissolved in 50-80 mL of deionized water and mixed to prepare solution c; solution b and solution c were injected into solution a and stirred for 4-5 h to obtain solution d, which was filtered to obtain precursor A1, which was washed and dried, and then subjected to a first calcination in an inert atmosphere to obtain precursor A2; 0.5-0.7 g of precursor A2, 4.1-4.5 g of glucose and 35-50 mL of The reaction mixture is mixed with ultrapure water and subjected to a hydrothermal reaction, followed by solid-liquid separation to obtain a solid and drying the solid. Finally, the dried solid is subjected to a second calcination in an inert atmosphere to obtain an iron single-atom catalyst for the efficient and directional conversion of rifamycin B to O, which is recorded as iron 1.

[0009] Furthermore, the washing is specifically: washing with deionized water and alcohol three times each.

[0010] Furthermore, the inert atmosphere is argon or nitrogen.

[0011] Furthermore, the first calcination is specifically as follows: a heating rate of 3-5°C / min, a calcination temperature of 600-650°C, and a calcination time of 4-5h.

[0012] Furthermore, the hydrothermal reaction is specifically as follows: the hydrothermal reaction temperature is 180-200° C., and the hydrothermal reaction time is 10-12 hours.

[0013] Furthermore, the second calcination is specifically as follows: a heating rate of 3-5°C / min, a calcination temperature of 900-950°C, and a calcination time of 4-5h.

[0014] In a second aspect, the present invention provides an iron single-atom catalyst for the efficient and directional conversion of rifamycin B to O, wherein the iron single-atom catalyst for the efficient and directional conversion of rifamycin B to O is prepared by the following steps:

[0015] 3.1-3.5 g of melamine was dissolved in 300-350 mL of deionized water at 80-95° C. to form solution a. 2.5-3.0 g of cyanuric acid was dissolved in 200-300 mL of deionized water at 80-95° C. to form solution b. 0.5-0.8 g of N-allylthiourea and 0.4-0.6 g of ferrous acetate were weighed and dissolved in 50-70 mL of deionized water and mixed to prepare solution c. Solution b and solution c were injected into solution a and stirred for 4-5 h to obtain solution d, which was filtered to obtain precursor B1. After washing and drying, the precursor was first calcined in an inert atmosphere to obtain precursor B2. 0.5-0.7 g of precursor B2, 4.1-4.5 g of glucose and 35-40 mL of Ultrapure water is mixed and a hydrothermal reaction is carried out, followed by solid-liquid separation to obtain a solid and dry it. Finally, the dried solid is subjected to a second calcination in an inert atmosphere to obtain an iron single-atom catalyst for the efficient and directional conversion of rifamycin B to O, which is recorded as iron-sulfur 1.

[0016] Furthermore, the washing is specifically: washing with deionized water and alcohol three times each.

[0017] Furthermore, the inert atmosphere is argon or nitrogen.

[0018] Furthermore, the first calcination is specifically as follows: a heating rate of 3-5°C / min, a calcination temperature of 600-650°C, and a calcination time of 4-5h.

[0019] Furthermore, the hydrothermal reaction is specifically as follows: the hydrothermal reaction temperature is 180-200° C., and the hydrothermal reaction time is 10-12 hours.

[0020] Furthermore, the second calcination is specifically as follows: a heating rate of 3-5°C / min, a calcination temperature of 900-950°C, and a calcination time of 4-5h.

[0021] In a third aspect, the present invention provides an iron single-atom catalyst for the efficient and directional conversion of rifamycin B to O, wherein the iron single-atom catalyst for the efficient and directional conversion of rifamycin B to O is prepared by the following steps:

[0022] 3.1-3.5 g of melamine was dissolved in 300-350 mL of deionized water at 90-95° C. to form solution a, 2.5-3.0 g of cyanuric acid was dissolved in 200-300 mL of deionized water at 90-95° C. to form solution b, 0.4-0.5 g of thiocyanic acid was weighed and dissolved in 50-80 mL of dimethyl sulfoxide to obtain solution c, 0.85-0.95 g of ferric acetylacetonate was weighed and dissolved in 90-100 mL of N,N-dimethylformamide to obtain solution d; solutions b, c, and d were injected into solution a and stirred for 4-6 h to obtain solution e, which was filtered to obtain precursor C1, which was washed and dried, and then subjected to a first calcination in an inert atmosphere to obtain precursor C2; 0.5-0.7 g of precursor C2, 4.1-4.3 g of glucose, and 35-50 mL of Ultrapure water is mixed and a hydrothermal reaction is carried out, followed by solid-liquid separation to obtain a solid and dry it. Finally, the dried solid is subjected to a second calcination in an inert atmosphere to obtain an iron single-atom catalyst for the efficient and directional conversion of rifamycin B to O, which is recorded as iron-sulfur 2.

[0023] Furthermore, the washing is specifically: washing with deionized water and alcohol three times each.

[0024] Furthermore, the inert atmosphere is argon or nitrogen.

[0025] Furthermore, the first calcination is specifically as follows: a heating rate of 3-5°C / min, a calcination temperature of 600-650°C, and a calcination time of 4-5h.

[0026] Furthermore, the hydrothermal reaction is specifically as follows: the hydrothermal reaction temperature is 180-200° C., and the hydrothermal reaction time is 10-12 hours.

[0027] Furthermore, the second calcination is specifically as follows: a heating rate of 3-5°C / min, a calcination temperature of 900-950°C, and a calcination time of 4-5h.

[0028] In a fourth aspect, the present invention provides an application of an iron single-atom catalyst for the efficient and directional conversion of rifamycin B to rifamycin O.

[0029] Furthermore, the application includes the following specific steps:

[0030] An iron single-atom catalyst for the efficient directional conversion of rifamycin B to O is added to a rifamycin B-containing solution, magnetically stirred for 30 to 40 minutes to obtain a mixed solution, and sodium persulfate is added for activation and conversion for 1 to 1.5 hours to complete the efficient directional conversion of rifamycin B to rifamycin O. The concentration of rifamycin B in the rifamycin B solution is 15,000 to 18,000 mg / L. The dosage of the iron single-atom catalyst for the efficient directional conversion of rifamycin B to O is 1.5 to 2 g / L. The dosage of the sodium persulfate is 130 to 140 mM.

[0031] The beneficial effects of the present invention are:

[0032] 1) By introducing the S element to regulate the coordination environment of the iron single atom, sodium persulfate is efficiently activated to regulate the electron transfer process from rifamycin B to rifamycin O.

[0033] 2) The doping of S element changes the conductivity of the catalyst and the adsorption structure between rifamycin B and the catalyst, thereby regulating the intensity and action site of electron transfer from rifamycin B to the catalyst and then to the oxidant, achieving efficient directional conversion while reducing the occurrence of side reactions. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of the coordination structure of the iron single-atom catalyst prepared in Example 1;

[0035] Figure 2 Schematic diagram of the coordination structure of the iron single-atom catalyst prepared in Example 2;

[0036] Figure 3 Schematic diagram of the coordination structure of the iron single-atom catalyst prepared in Example 3;

[0037] Figure 4 The X-ray diffraction patterns of the iron single-atom catalysts prepared in Example 1, Example 2, and Example 3;

[0038] Figure 5 Fourier transform Fe K-edge R-space X-ray extended edge absorption fine structure spectra of the iron single atom catalyst, Fe foil, FePc and FeS prepared in Example 1, Example 2 and Example 3;

[0039] Figure 6 This is a graph showing the change in mass yield of rifamycin O with increasing addition of sodium persulfate without adding iron single atom catalyst;

[0040] Figure 7 This is the experimental diagram of the mass yield of rifamycin O;

[0041] Figure 8 This is an experimental diagram of the purity of rifamycin O;

[0042] Figure 9 This is a graph showing how the mass yield of rifamycin O changes as the S / Fe ratio in the iron single-atom catalyst prepared in Example 3 increases. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to illustrate the present invention, rather than to represent all embodiments. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0044] For experimental methods where specific experimental conditions are not specified, conventional experimental conditions or those recommended by the manufacturer are generally followed. Materials and reagents used were commercially available unless otherwise specified.

[0045] In a first aspect, the present invention provides a method for preparing an iron single-atom catalyst for the efficient and directional conversion of rifamycin B to O, comprising the following steps:

[0046] Dissolve 3.1-3.5 g of melamine in 300-350 mL of deionized water at 80-95 °C with magnetic stirring to form solution a. Dissolve 2.5-3.0 g of cyanuric acid in 200-250 mL of deionized water at 80-95 °C with magnetic stirring to form solution b. Weigh 0.4-0.5 g of oxalic acid and 0.5-0.6 g of ferric nitrate nonahydrate and dissolve them in 50-80 mL of Deionized water was mixed to prepare solution c; solution b and solution c were injected into solution a and stirred for 4-5 hours to obtain solution d; solution d was then filtered to obtain precursor A1, and precursor A1 was washed three times with deionized water and alcohol, and then dried at 70-75°C for 24-26 hours; the dried precursor A1 was then placed in a tube furnace and heated to 600-650°C at a heating rate of 3-5°C / min under a flowing inert atmosphere, calcined for 4-5 hours, and taken out after cooling to obtain precursor A2; 0.5-0.7g precursor A2, 4.1-4.5g glucose and 35-50mL The mixture is mixed with ultrapure water and added to the inner container of a reactor. A hydrothermal reaction is carried out at 180-200°C for 10-12 hours, followed by solid-liquid separation to obtain a solid. The solid is then dried at 70-75°C for 24-26 hours, and then placed in a tube furnace and heated at 3-5°C / min to 900-950°C for 4-5 hours in an inert atmosphere to obtain an iron single-atom catalyst for the efficient and directional conversion of rifamycin B to O, denoted as Fe-1. The inert atmosphere is argon or nitrogen.

[0047] In a second aspect, the present invention also provides a method for preparing an iron single-atom catalyst for the efficient and directional conversion of rifamycin B to O, comprising the following steps:

[0048] Dissolve 3.1-3.5 g of melamine in 300-350 mL of deionized water at 80-95 °C with magnetic stirring to form solution a. Dissolve 2.5-3.0 g of cyanuric acid in 200-300 mL of deionized water at 80-95 °C with magnetic stirring to form solution b. Weigh 0.5-0.8 g of N-allylthiourea and 0.4-0.6 g of ferrous acetate and dissolve them in 50-70 mL of Deionized water was mixed to prepare solution c; solution b and solution c were injected into solution a and stirred for 4-5 hours to obtain solution d; solution d was then filtered to obtain precursor B1, and precursor B1 was washed three times with deionized water and alcohol, and then dried at 70-80°C for 24-26 hours; the dried precursor B1 was then placed in a tube furnace and heated to 600-650°C at a heating rate of 3-5°C / min under a flowing argon atmosphere, calcined for 4-5 hours, and taken out after cooling to obtain precursor B2; 0.5-0.7g precursor B2, 4.1-4.5g glucose and 35-40mL The mixture is mixed with ultrapure water and added to the inner container of a reactor. A hydrothermal reaction is carried out at 180-200°C for 10-12 hours, followed by solid-liquid separation to obtain a solid. The solid is then dried at 60-70°C for 24-26 hours, and then placed in a tube furnace and heated to 900-950°C at a rate of 3-5°C / min in an argon atmosphere for 4-5 hours. Finally, an iron single-atom catalyst for the efficient and directional conversion of rifamycin B to O is obtained, which is recorded as Fe-S 1. The inert atmosphere is argon or nitrogen.

[0049] In a third aspect, the present invention also provides a method for preparing an iron single-atom catalyst for the efficient and directional conversion of rifamycin B to O, comprising the following steps:

[0050] Dissolve 3.1-3.5 g of melamine in 300-350 mL of deionized water at 90-95 °C with magnetic stirring to form solution a. Dissolve 2.5-3.0 g of cyanuric acid in 200-300 mL of deionized water at 90-95 °C with magnetic stirring to form solution b. Weigh 0.4-0.5 g of thiocyanic acid and dissolve it in 50-80 mL of dimethyl sulfoxide to obtain solution c. Weigh 0.85-0.95 g of ferric acetylacetonate and dissolve it in 90-100 mL of Solution d was obtained from N, N-dimethylformamide; solution b, solution c and solution d were injected into solution a and stirred for 4-5 hours to obtain solution e; solution e was filtered to obtain precursor C1, and precursor C1 was washed three times with deionized water and alcohol, and then dried at 70-80°C for 24-26 hours; the dried precursor C1 was then placed in a tube furnace and heated to 600-650°C at a heating rate of 3-5°C / min under a flowing argon atmosphere, calcined for 4-5 hours, and taken out after cooling to obtain precursor C2; 0.5-0.7g of precursor C2, 4.1-4.3g of glucose and 35-50mL of The mixture is mixed with ultrapure water and added to the inner container of a reactor. A hydrothermal reaction is carried out at 180-190°C for 10-12 hours, followed by solid-liquid separation to obtain a solid. The solid is then dried at 70-80°C for 24-26 hours, and then placed in a tube furnace and heated to 900-950°C at a rate of 3-5°C / min in an argon atmosphere for 4-5 hours. Finally, an iron single-atom catalyst for the efficient and directional conversion of rifamycin B to O is obtained, which is recorded as FeS2. The inert atmosphere is argon or nitrogen.

[0051] Example 1 An iron single-atom catalyst (Iron 1) for the efficient and directional conversion of rifamycin B to O was prepared by the following steps:

[0052] 3.1g of melamine was dissolved in 300mL of deionized water at 80°C with magnetic stirring to form solution a. 2.5g of cyanuric acid was dissolved in 200mL of deionized water at 80°C with magnetic stirring to form solution b. 0.4g of oxalic acid and 0.5g of ferric nitrate nonahydrate were weighed and dissolved in 50mL of deionized water and mixed to prepare solution c. Solution b and solution c were slowly injected into solution a and stirred for 4 hours to obtain solution d. Solution d was then filtered to obtain precursor A1. Precursor A1 was washed three times with deionized water and three times with alcohol, then dried at 70°C for 24 hours. The dried precursor A1 was then heated to 600°C in a tube furnace under flowing argon at a heating rate of 5°C / min. It was calcined for 4 hours, cooled, and removed to obtain precursor A2. 0.5 g of precursor A2, 4.1 g of glucose, and 35 mL of ultrapure water were mixed and added to the inner container of the reactor. After hydrothermal reaction at 180°C for 10 h, solid-liquid separation was performed to obtain a solid. The solid was then dried at 70°C for 24 h. The dried solid was placed in a tubular furnace and heated to 900°C at a rate of 5°C / min in an argon atmosphere and calcined for 4 h. Finally, an iron single-atom catalyst for the efficient and directional conversion of rifamycin B to O was obtained, which was recorded as Fe-1.

[0053] Example 2 An iron single-atom catalyst (iron-sulfur 1) for the efficient and directional conversion of rifamycin B to O was prepared by the following steps:

[0054] 3.1 g of melamine was dissolved in 300 mL of deionized water at 80°C with magnetic stirring to form solution a. 2.5 g of cyanuric acid was dissolved in 200 mL of deionized water at 80°C with magnetic stirring to form solution b. 0.5 g of N-allylthiourea and 0.4 g of ferrous acetate were weighed and dissolved in 50 mL of deionized water and mixed to prepare solution c. Solution b and solution c were slowly injected into solution a and stirred for 4 hours to obtain solution d. Solution d was then filtered to obtain precursor B1. Precursor B1 was washed three times with deionized water and three times with alcohol, then dried at 70°C for 24 hours. The dried precursor B1 was then heated to 600°C in a tube furnace under flowing argon at a heating rate of 3°C / min. It was calcined for 4 hours, cooled, and removed to obtain precursor B2. 0.5 g of precursor B2, 4.1 g of glucose and 35 mL of ultrapure water were mixed and added to the inner container of the reactor. After hydrothermal reaction at 180°C for 10 h, solid-liquid separation was performed to obtain a solid. The solid was then dried at 60°C for 24 h, and the dried solid was placed in a tubular furnace and heated to 900°C at 5°C / min in an argon atmosphere and calcined for 4 h. Finally, an iron single-atom catalyst for the efficient and directional conversion of rifamycin B to O was obtained, which was recorded as iron-sulfur 1.

[0055] Example 3 An iron single-atom catalyst (FeS2) for the efficient and directional conversion of rifamycin B to O was prepared by the following steps:

[0056] 3.1 g of melamine was dissolved in 300 mL of deionized water at 90°C with magnetic stirring to form solution a. 2.5 g of cyanuric acid was dissolved in 200 mL of deionized water at 90°C with magnetic stirring to form solution b. 0.4 g of thiocyanic acid was dissolved in 50 mL of dimethyl sulfoxide to form solution c. 0.85 g of ferric acetylacetonate was dissolved in 90 mL of N,N-dimethylformamide to form solution d. Solutions b, c, and d were slowly injected into solution a and stirred for 4 hours to obtain solution e. Solution e was filtered to obtain precursor C1. Precursor C1 was washed three times with deionized water and three times with alcohol, then dried at 70°C for 24 hours. The dried precursor C1 was then heated to 600°C in a tube furnace under flowing argon at a heating rate of 5°C / min. It was calcined for 4 hours, cooled, and removed to obtain precursor C2. 0.5g of precursor C2, 4.1g of glucose, and 35mL of ultrapure water were mixed and added to the reactor liner. After hydrothermal reaction at 180°C for 10h, solid-liquid separation was performed to obtain a solid. The solid was then dried at 70°C for 24h. The dried solid was placed in a tube furnace and calcined at 900°C in an argon atmosphere at a rate of 5°C / min for 4h, ultimately obtaining an iron single-atom catalyst for the efficient and directional conversion of rifamycin B to O, designated as FeS2. By varying the added mass of thiocyanate to 0.08g, 0.16g, 0.32g, 0.4g, 0.6g, 0.7g, and 0.9g, FeS2 with S / Fe ratios of 0.2:1, 0.4:1, 0.8:1, 1:1, 1.5:1, 2:1, and 3:1, respectively, was prepared.

[0057] Application Example 1: Conversion of rifamycin B to O using sodium persulfate activated by different catalysts (Fe 1, FeS 1, FeS 2)

[0058] (1) Take 50 mL of rifamycin B solution and add it to a 100 mL beaker. Add 2 g / L of the iron single atom catalyst (Iron 1) prepared in Example 1, the iron single atom catalyst (Iron Sulfur 1) prepared in Example 2, and the iron single atom catalyst (Iron Sulfur 2) prepared in Example 3 respectively and perform ultrasonic dispersion. Add 5 wt % butyl acetate (1.5 mL) and magnetically stir for 30 min. Then, add sodium persulfate at a concentration of 140 mM.

[0059] (2) Start timing after adding sodium persulfate. After 1 hour, add 30 mL of butyl acetate as an extractant to the beaker. Stir for 5 minutes and pour into a separatory funnel for separation. After standing for 4 hours, obvious stratification will appear. Take the upper butyl acetate phase for detection.

[0060] (3) The concentrations of rifamycin O and impurities in the butyl acetate phase were determined by high performance liquid chromatography, and the mass yield and purity of rifamycin O were calculated.

[0061] Figure 1 Schematic diagram of the coordination structure of the iron single-atom catalyst prepared in Example 1; Figure 2 Schematic diagram of the coordination structure of the iron single-atom catalyst prepared in Example 2; Figure 3 Schematic diagram of the coordination structure of the iron single atom catalyst prepared in Example 3. Figure 1 As shown, the iron single-atom catalyst prepared in Example 1 is a classic Fe-N4 configuration, with each iron atom coordinated with four nitrogen atoms; Figure 2 As shown, the iron single-atom catalyst prepared in Example 2 introduces a sulfur atom to directly coordinate with iron, and the coordination environment of iron becomes Fe-SN3 configuration, which triggers the 3d orbital splitting of Fe and the enhancement of spin electron rearrangement, thereby enhancing the adsorption of the Fe site on the hydroxyl group of rifamycin B; Figure 3 As shown, the iron single-atom catalyst prepared in Example 3 introduces a sulfur atom to coordinate with N on the carrier, and the coordination environment of iron becomes Fe-N4S configuration. While inducing the splitting of the 3d orbital of Fe, the positive charge of the central Fe is enhanced through the remote electron-withdrawing effect of sulfur, thereby achieving the optimal adsorption effect of the Fe site on the hydroxyl group of rifamycin B.

[0062] Figure 4 The X-ray diffraction patterns of the iron single atom catalysts prepared in Example 1, Example 2 and Example 3 are shown. Figure 4 As shown, the iron single-atom catalysts prepared in Example 1, Example 2 and Example 3 basically maintained the structure of nitrogen-doped carbon, and no diffraction peak of iron nanoparticles appeared, proving that the iron in each iron single-atom catalyst existed in the form of small-sized atoms. Figure 5 The following are Fourier transform Fe K-edge R-space X-ray extended edge absorption fine structure spectra of the iron single atom catalyst, iron foil (Fe foil), FePc and FeS prepared in Examples 1, 2 and 3. Figure 5 As shown, it was found that iron 1 and iron sulfur 2 had a characteristic peak at 1.4Å that clearly corresponded to the Fe-N coordination scattering, while the dominant peak of iron sulfur 1 corresponded to the Fe-S coordination bond of the FeS standard, indicating that there was a Fe-S coordination configuration inside iron sulfur 1. Figure 6 This is a graph showing the change in mass yield of rifamycin O with increasing addition of sodium persulfate without adding iron single atom catalyst; Figure 6 It shows that in the absence of iron single-atom catalyst, the mass yield of rifamycin O increases with the increase of sodium persulfate addition, but when the addition amount reaches 140mM, further increasing the amount of sodium persulfate addition can no longer increase the yield, reaching a bottleneck. At this time, the mass yield of rifamycin O reaches 80%. Figure 7 This is the experimental diagram of the mass yield of rifamycin O; Figure 8 This is an experimental diagram of the purity of rifamycin O; Figure 7 It was shown that when 5 wt % butyl acetate, 2 g / L of the iron single atom catalyst prepared in Example 3, and 140 mM sodium persulfate were added, the mass yield of rifamycin O reached a maximum of 91.35%; Figure 8 It is shown that when 5 wt % of butyl acetate, 2 g / L of the iron single atom catalyst prepared in Example 3 and 140 mM of sodium persulfate are added, the purity of rifamycin O reaches up to 94.97%, which is better than the existing process. Figure 9 This is a graph showing the change in mass yield of rifamycin O as the S / Fe ratio in the iron single-atom catalyst prepared in Example 3 increases; Figure 9 It shows that the mass yield of rifamycin O varies with the S / Fe ratio in the iron single atom catalyst prepared in Example 3. When the S / Fe ratio in the iron single atom catalyst prepared in Example 3 is 1:1, the optimal mass yield is 91.35%.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An iron single-atom catalyst for the efficient and directional conversion of rifamycin B to O, characterized in that: The iron single-atom catalyst for the efficient and directional conversion of rifamycin B to O is prepared by the following steps: 3.1-3.5 g of melamine is dissolved in 300-350 mL of deionized water at 90-95° C. to form solution a, 2.5-3.0 g of cyanuric acid is dissolved in 200-300 mL of deionized water at 90-95° C. to form solution b, 0.4-0.5 g of thiocyanic acid is weighed and dissolved in 50-80 mL of dimethyl sulfoxide to obtain solution c, and 0.85-0.95 g of ferric acetylacetonate is weighed and dissolved in 90-100 mL of N,N-dimethylformamide to obtain solution d; solutions b, c, and d are injected into solution a and stirred for 4-6 hours to obtain solution e, which is filtered to obtain precursor C1, washed and dried, and then calcined in an inert atmosphere to obtain precursor C2; 0.5-0.7 g of precursor C2, 4.1-4.3 g of glucose and 35-50 mL of ultrapure water were mixed and subjected to a hydrothermal reaction. The solid was then separated by solid-liquid separation to obtain a solid and dried. Finally, the dried solid was subjected to a second calcination in an inert atmosphere to obtain an iron single-atom catalyst for the efficient and directional conversion of rifamycin B to O, which was recorded as iron-sulfur 2.

2. The iron single-atom catalyst for efficient directional conversion of rifamycin B to O according to claim 1, characterized in that The washing is specifically as follows: washing with deionized water and alcohol three times each.

3. The iron single-atom catalyst for the efficient and directional conversion of rifamycin B to O according to claim 1, characterized in that The inert atmosphere is argon or nitrogen.

4. The iron single-atom catalyst for efficient directional conversion of rifamycin B to O according to claim 1, characterized in that The first calcination is specifically as follows: a heating rate of 3 to 5° C. / min, a calcination temperature of 600 to 650° C., and a calcination time of 4 to 5 hours.

5. The iron single-atom catalyst for efficient directional conversion of rifamycin B to O according to claim 1, characterized in that The hydrothermal reaction is specifically as follows: the hydrothermal reaction temperature is 180-200° C., and the hydrothermal reaction time is 10-12 hours.

6. The iron single-atom catalyst for efficient directional conversion of rifamycin B to O according to claim 1, characterized in that The second calcination is specifically as follows: a heating rate of 3 to 5° C. / min, a calcination temperature of 900 to 950° C., and a calcination time of 4 to 5 hours.

7. Use of the iron single-atom catalyst for the efficient and directional conversion of rifamycin B to O according to claim 1 for the efficient and directional conversion of rifamycin B to rifamycin O.

8. The use according to claim 7, characterized in that The application includes the following specific steps: An iron single-atom catalyst for efficient directional conversion of rifamycin B to O is added to a liquid containing rifamycin B, magnetically stirred for 30 to 40 minutes to obtain a mixed solution, and sodium persulfate is added to activate and convert for 1 to 1.5 hours to complete the efficient directional conversion of rifamycin B to rifamycin O. The concentration of rifamycin B in the feed solution is 15000-18000 mg / L; the dosage of the iron single-atom catalyst for high-efficiency directional conversion of rifamycin B to O is 1.5-2 g / L; and the dosage of the sodium persulfate is 130-140 mM.

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