Method for catalytically synthesizing 3-mercaptopropionic acid by MgO-loaded molecular sieve

Abstract

The invention relates to a method for catalytically synthesizing 3-mercaptopropionic acid by an MgO-loaded molecular sieve, and belongs to the technical field of organic synthesis. In order to solve the problems that an existing solid-phase catalyst is not easy to regenerate and the selectivity of 3-mercaptopropionic acid is low, the preparation method comprises the following steps: firstly, mixing a roasted molecular sieve, magnesium acetate tetrahydrate powder and distilled water to obtain an impregnated solid mixture, and carrying out temperature programming roasting on the solid mixture to obtain an MgO-loaded molecular sieve catalyst with the MgO loading capacity of 0.5-20%; and mixing the MgO-loaded molecular sieve catalyst, acrylic acid and an organic solvent, introducing hydrogen sulfide, and carrying out a heating reaction to obtain 3-mercaptopropionic acid. The MgO-loaded molecular sieve is used for catalyzing the addition reaction of hydrogen sulfide and acrylic acid to synthesize 3-mercaptopropionic acid, and the selectivity and selectivity of 3-mercaptopropionic acid are both higher than 90%. The MgO-loaded molecular sieve catalyst prepared by the invention has the characteristics of high catalytic activity, simple synthesis and mild catalytic synthesis conditions.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, and in particular relates to a method for catalyzing and synthesizing 3-mercaptopropionic acid using a loaded MgO molecular sieve. Background Art

[0002] 3-Mercaptopropionic acid is an important organic synthesis intermediate, widely used in organic synthesis in medicine, pesticides and materials. The chelating agents carboxyethyl thiosuccinic acid (CETSA) and carboxyethyl thiosuccinic acid synthesized by the addition of 3-mercaptopropionic acid with maleic acid and maleic anhydride have the characteristics of acidity and strong chelating ability, and are suitable for cleaning and descaling in processes such as metal processing and oil field exploitation. Using 3-mercaptopropionic acid self-assembled monolayer as a template, it can induce the nucleation and growth of crystals such as calcium oxalate and calcium carbonate to generate a two-dimensional self-assembled monolayer showing unique structure and surface properties. The esterification product of 3-mercaptopropionic acid and pentaerythritol, pentaerythritol tetrakis (3-mercaptocarboxylic acid) ester (PETMP), can be used to synthesize high refractive index polymers. This polymer has a high refractive index, is light in weight, easy to process, and low in cost. It can replace glass, such as resin lenses and other fields. 3-Mercaptopropionic acid is used in the field of concrete water reducers in the largest amount. In the process of synthesizing polycarboxylic acid water-reducing agent, 3-mercaptopropionic acid can be used as a chain transfer agent to regulate the molecular weight of polycarboxylic acid and improve the water reduction rate and slump retention performance of concrete.

[0003] The method for synthesizing 3-mercaptopropionic acid is divided into two directions: homogeneous and heterogeneous. In homogeneous reactions, water is often used as a solvent, and NaHS and Na2S are used as thiol reagents to react with acrylic acid or acrylonitrile under strong alkaline conditions. The product of the reaction with acrylic acid is the sodium salt form of 3-mercaptopropionic acid, which needs to be acidified and then extracted to obtain 3-mercaptopropionic acid. The product of the reaction with acrylonitrile is the sodium salt form of 3-mercaptopropionic acid, which needs to be hydrolyzed, then acidified and extracted to obtain 3-mercaptopropionic acid. A large amount of inorganic acid and inorganic base need to be used in the whole process, thus generating a large amount of high-salt wastewater, and a large amount of organic solvent is also required in the extraction process.

[0004] Solid phase catalysis mostly uses alkaline ion exchange resins as catalysts, such as Amberlyst A21, Amberlyst A26, modified cyclic amine (guanidine) resins, etc. These anion exchange resins show good activity and good selectivity for 3-mercaptopropionic acid in the process of catalyzing the reaction of acrylic acid and hydrogen sulfide. However, the prominent disadvantage of ion exchange resins is that the resin swells significantly in the solvent, is easy to break, and is not easy to regenerate after deactivation. Some studies have used self-made MgO with high mechanical strength as a catalyst to catalyze the addition of acrylic acid and hydrogen sulfide. The acrylic acid conversion rate is above 98%, but the selectivity for 3-mercaptopropionic acid is around 36%.

[0005] Therefore, there is an urgent need in the art to develop a high-activity, high-selectivity, high-mechanical-strength, regenerable solid-phase catalyst to catalyze the one-step addition of acrylic acid and hydrogen sulfide to synthesize 3-mercaptopropionic acid. Summary of the invention

[0006] In order to solve the problems that the existing solid phase catalyst is difficult to regenerate and the selectivity of 3-mercaptopropionic acid is low, the present invention provides a method for catalyzing the synthesis of 3-mercaptopropionic acid by a loaded MgO molecular sieve.

[0007] The technical solution of the present invention:

[0008] A method for catalyzing the synthesis of 3-mercaptopropionic acid using a loaded MgO molecular sieve comprises the following steps:

[0009] Step 1, preparing a loaded MgO molecular sieve catalyst: mixing the calcined molecular sieve, magnesium acetate tetrahydrate powder and distilled water in a mass volume ratio of 20.0 g: 0.532-21.28 g: 25 mL to obtain an impregnated solid mixture, and subjecting the solid mixture to programmed temperature calcination to obtain a loaded MgO molecular sieve catalyst with a MgO loading of 0.5-20%;

[0010] Step 2: Mix the supported MgO molecular sieve catalyst obtained in step 1, acrylic acid and an organic solvent in a certain mass volume ratio, introduce hydrogen sulfide to a certain pressure, heat to a reaction temperature, and react for a certain time to obtain 3-mercaptopropionic acid.

[0011] Furthermore, the molecular sieve in step 1 is HY molecular sieve, HZSM5 molecular sieve, HBETA molecular sieve, MCM-41 molecular sieve or SBA-15 molecular sieve.

[0012] Furthermore, the calcination method of the molecular sieve is to increase the temperature from room temperature to 450°C at a heating rate of 5°C / min and calcine at 450°C for 4h.

[0013] Furthermore, the programmed temperature rise calcination in step 1 is to heat the material from room temperature to 200°C at a heating rate of 5°C / min, keep the temperature at 200°C for 1 hour, then heat the material to 500°C at a heating rate of 5°C / min, and calcine at 500°C for 5 hours.

[0014] Furthermore, in step 2, the mass volume ratio of the supported MgO molecular sieve catalyst, acrylic acid and organic solvent is 0.2-0.5 g:10 mL:50 mL.

[0015] Furthermore, the organic solvent in step 2 is a protic solvent or an aprotic solvent.

[0016] Further, the protic solvent is an alcohol solvent or an amine solvent; the alcohol solvent is methanol, ethanol, propanol, isopropanol or butanol; the amine solvent is ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, pyrrolidine, N-alkylpyrrolidine, piperidine, N-alkylpiperidine, piperazine, N-alkylpiperazine or morpholine;

[0017] The aprotic solvent is an ether solvent, an amide solvent, a ketone solvent, a nitrile solvent, pyridine or dimethyl sulfoxide; the ether solvent is diethyl ether, methyl tert-butyl ether, 1,4-dioxane, ethylene glycol monomethyl ether or ethylene glycol dimethyl ether; the amide solvent is N,N-dimethylformamide, N,N-dimethylacetamide, N,N'-diethylformamide or N-methylpyrrolidone; the ketone solvent is acetone, butanone or cyclohexanone; the nitrile solvent is acetonitrile or propionitrile.

[0018] Furthermore, in step 2, the reaction temperature is 30-120° C., the pressure of hydrogen sulfide is 0.1-5 MPa, and the reaction time is 1-4 h.

[0019] Furthermore, the reaction temperature in step 2 is 40-100° C., and the pressure of hydrogen sulfide is 0.2-4 MPa.

[0020] Furthermore, the reaction temperature in step 2 is 50-90° C., and the pressure of hydrogen sulfide is 0.5-2.5 MPa.

[0021] Beneficial effects of the present invention:

[0022] The present invention uses a loaded MgO molecular sieve to catalyze the addition reaction of hydrogen sulfide and acrylic acid to synthesize 3-mercaptopropionic acid, and the conversion rate and selectivity of 3-mercaptopropionic acid are both higher than 90%. The loaded MgO molecular sieve catalyst prepared by the present invention has the characteristics of high catalytic activity, simple synthesis, and mild catalytic synthesis conditions. In the present invention, the MgO loaded molecular sieve is prepared by impregnating a magnesium acetate aqueous solution onto a molecular sieve and then roasting it. MgO is not on the surface of the molecular sieve, but in the pores of the molecular sieve. The MgO loaded molecular sieve can be a powdered molecular sieve or a molded molecular sieve. The molded molecular sieve can be applied to a trickle bed reaction, and can also be applied to a variety of reaction forms such as a fluidized bed and a reactor to realize a synthetic reaction. The molded molecular sieve has a high hardness, and the phenomenon of swelling and breaking that may occur in an ion exchange resin in a solvent will not occur. At the same time, the molecular sieve has good temperature resistance, and the failed catalyst can be regenerated by high-temperature roasting to achieve the purpose of repeated use. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The infrared spectrum of the MgO / HY catalyst with a MgO loading of 5% prepared in Example 1;

[0024] Figure 2 The infrared spectrum of the MgO / HY catalyst with a MgO loading of 10% prepared in Example 2;

[0025] Figure 3 is the infrared spectrum of the acidic HY molecular sieve catalyst in Comparative Example 1;

[0026] Figure 4 is the infrared spectrum of MgO in Comparative Example 2;

[0027] Figure 5 XRD spectrum of the MgO / HY catalyst with a MgO loading of 5% prepared in Example 1;

[0028] Figure 6 XRD spectrum of the MgO / HY catalyst with a MgO loading of 10% prepared in Example 2;

[0029] Figure 7 is the XRD spectrum of the acidic HY molecular sieve catalyst in Comparative Example 1;

[0030] Figure 8 This is the XRD spectrum of MgO in Comparative Example 2. DETAILED DESCRIPTION

[0031] The technical solution of the present invention is further described below in conjunction with the embodiments, but it is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention shall be included in the protection scope of the present invention. The process equipment or devices not specifically noted in the following embodiments are all conventional equipment or devices in the art. If not specifically specified, the raw materials used in the embodiments of the present invention can be obtained commercially; if not specifically specified, the technical means used in the embodiments of the present invention are all conventional means well known to those skilled in the art.

[0032] Example 1

[0033] This embodiment provides a method for catalyzing the synthesis of 3-mercaptopropionic acid using a supported MgO molecular sieve, comprising the following steps:

[0034] Step 1: Preparation of loaded MgO molecular sieve catalyst:

[0035] The HY molecular sieve solid powder with a silicon-aluminum ratio of 40 was placed in a muffle furnace, heated from room temperature to 450°C at a heating rate of 5°C / min, and calcined at 450°C for 4h.

[0036] In a three-necked flask, 5.32 g of magnesium acetate tetrahydrate powder was accurately weighed and dissolved in 25 mL of distilled water, and 20.0 g of calcined HY molecular sieve was added and mixed thoroughly for impregnation. The impregnated solid mixture was placed in a muffle furnace for programmed temperature calcination, and the temperature was increased from room temperature to 200° C. at a heating rate of 5° C. / min. After being kept at a constant temperature at 200° C. for 1 hour, the temperature was increased to 500° C. at a heating rate of 5° C. / min, and calcined at 500° C. for 5 hours to obtain a MgO / HY catalyst with a MgO loading of 5%.

[0037] Step 2: Add 0.2 g of the MgO / HY catalyst obtained in step 1, 10 mL of acrylic acid and 50 mL of N,N-dimethylformamide (DMF) into an autoclave, introduce hydrogen sulfide to 0.70 MPa, heat to 60° C., react for 2 hours, and analyze by gas chromatography.

[0038] In this example, the acrylic acid conversion rate is 96.6%, and the 3-mercaptopropionic acid selectivity is 93.4%.

[0039] Example 2

[0040] This embodiment provides a method for catalyzing the synthesis of 3-mercaptopropionic acid using a supported MgO molecular sieve, comprising the following steps:

[0041] Step 1: Preparation of loaded MgO molecular sieve catalyst:

[0042] The HY molecular sieve solid powder with a silicon-aluminum ratio of 40 was placed in a muffle furnace, heated from room temperature to 450°C at a heating rate of 5°C / min, and calcined at 450°C for 4h.

[0043] In a three-necked flask, 10.64 g of magnesium acetate tetrahydrate powder was accurately weighed and dissolved in 25 mL of distilled water at 40-50° C., 20.0 g of calcined HY molecular sieve was added, mixed and impregnated to obtain an impregnated solid mixture, the obtained solid mixture was dried at room temperature for 24 h, and then placed in a muffle furnace for programmed temperature roasting, the temperature was raised from room temperature to 200° C. at a heating rate of 5° C. / min, kept at a constant temperature at 200° C. for 1 h, and then raised to 500° C. at a heating rate of 5° C. / min, and roasted at 500° C. for 5 h to obtain a MgO / HY catalyst with a MgO loading of 10%.

[0044] Step 2: Add 0.2 g of the MgO / HY catalyst obtained in step 1, 10 mL of acrylic acid and 50 mL of N,N-dimethylformamide (DMF) into an autoclave, introduce hydrogen sulfide to 0.70 MPa, heat to 80° C., react for 2 hours, and analyze by gas chromatography.

[0045] In this example, the acrylic acid conversion rate is 96.1% and the selectivity is 94.6%.

[0046] Example 3

[0047] This embodiment provides a method for catalyzing the synthesis of 3-mercaptopropionic acid using a supported MgO molecular sieve, comprising the following steps:

[0048] Step 1: Preparation of loaded MgO molecular sieve catalyst:

[0049] The HY molecular sieve solid powder with a silicon-aluminum ratio of 40 was placed in a muffle furnace, heated from room temperature to 450°C at a heating rate of 5°C / min, and calcined at 450°C for 4h.

[0050] In a three-necked flask, 10.64 g of magnesium acetate tetrahydrate powder was accurately weighed and dissolved in 25 mL of warm distilled water, and 20.0 g of calcined HY molecular sieve was added and mixed thoroughly to obtain an impregnated solid mixture. The obtained solid mixture was dried at room temperature for 24 h, and then placed in a muffle furnace for programmed temperature roasting, the temperature was raised from room temperature to 200 ° C at a heating rate of 5 ° C / min, and after keeping constant temperature at 200 ° C for 1 h, the temperature was raised to 500 ° C at a heating rate of 5 ° C / min, and roasted at 500 ° C for 5 h to obtain a MgO / HY catalyst with a MgO loading of 10%.

[0051] Step 2: Add 0.2 g of the MgO / HY catalyst obtained in step 1, 10 mL of acrylic acid and 50 mL of N,N-dimethylformamide (DMF) into an autoclave, introduce hydrogen sulfide to 0.70 MPa, heat to 60° C., react for 2 hours, and analyze by gas chromatography.

[0052] In this example, the acrylic acid conversion rate is 89.0%, and the selectivity is 90.6%.

[0053] Example 4

[0054] This embodiment provides a method for catalyzing the synthesis of 3-mercaptopropionic acid using a supported MgO molecular sieve, comprising the following steps:

[0055] Step 1: Preparation of loaded MgO molecular sieve catalyst:

[0056] The HY molecular sieve solid powder with a silicon-aluminum ratio of 40 was placed in a muffle furnace, heated from room temperature to 450°C at a heating rate of 5°C / min, and calcined at 450°C for 4h.

[0057] In a three-necked flask, 5.32 g of magnesium acetate tetrahydrate powder was accurately weighed and dissolved in 25 mL of warm distilled water, and 20.0 g of calcined HY molecular sieve was added and mixed thoroughly for impregnation. The impregnated solid mixture was placed in a muffle furnace for programmed temperature calcination, and the temperature was increased from room temperature to 200° C. at a heating rate of 5° C. / min. After being kept at a constant temperature at 200° C. for 1 h, the temperature was increased to 500° C. at a heating rate of 5° C. / min, and calcined at 500° C. for 5 h to obtain a MgO / HY catalyst with a MgO loading of 5%.

[0058] Step 2: Add 0.2 g of the MgO / HY catalyst obtained in step 1, 10 mL of acrylic acid and 50 mL of N,N-dimethylformamide (DMF) into an autoclave, introduce hydrogen sulfide to 0.70 MPa, heat to 60° C., react for 1 hour, and analyze by gas chromatography.

[0059] In this example, the acrylic acid conversion rate is 95.1% and the selectivity is 93.3%.

[0060] Comparative Example 1

[0061] This comparative example provides a method for synthesizing 3-mercaptopropionic acid using only HY molecular sieve as catalyst, comprising the following steps:

[0062] Step 1, place 10g of HY molecular sieve solid powder with a silicon-aluminum ratio of 40 in 100mL of 5% ammonium nitrate aqueous solution, stir at 80°C for 5h, filter and collect the solid, dry at 80°C for 5h, and then calcine at 400°C for 10h;

[0063] Step 2: Repeat the treatment method of step 1 three times to obtain an acidic HY molecular sieve catalyst.

[0064] Step 3: Add 0.2 g of the acidic HY molecular sieve obtained in step 2, 10 mL of acrylic acid and 50 mL of N,N-dimethylformamide (DMF) into an autoclave, introduce hydrogen sulfide to 0.70 MPa, heat to 60°C, react for 4 hours, and analyze by gas chromatography.

[0065] The acrylic acid conversion rate of this comparative example was 94.2%, and the selectivity was 92.1%.

[0066] Comparative Example 2

[0067] This comparative example provides a method for catalyzing the synthesis of 3-mercaptopropionic acid by MgO, comprising the following steps:

[0068] 0.2 g MgO, 10 mL acrylic acid and 50 mL N,N-dimethylformamide (DMF) were added to the autoclave, hydrogen sulfide was introduced to 0.70 MPa, the autoclave was heated to 60°C, the reaction time was 2 hours, and gas chromatography was used for analysis.

[0069] The acrylic acid conversion rate of this comparative example was 96.8%, and the selectivity was 93.5%.

[0070] After the reaction was completed, it was found that the magnesium oxide was completely dissolved in the reaction solution. Although the catalytic reaction proceeded well, the purpose of separating the catalyst well could not be achieved.

[0071] Figure 1-Figure 4 The infrared spectra are MgO / HY catalyst with MgO loading of 5%, MgO / HY catalyst with MgO loading of 10%, acidic HY molecular sieve catalyst and MgO in sequence; Figure 5-Figure 8 The XRD (X-ray diffraction) spectra of MgO / HY catalyst with 5% MgO loading, MgO / HY catalyst with 10% MgO loading, acidic HY molecular sieve catalyst and MgO are shown in order; from the XRD spectra, the spectra of acidic HY molecular sieve catalyst, MgO / HY catalyst with 5% MgO loading and MgO / HY catalyst with 10% MgO loading are basically the same, while MgO has sharp peaks at 43.04 and 62.4, while acidic HY molecular sieve catalyst, MgO / HY catalyst with 5% MgO loading and MgO / HY catalyst with 10% MgO loading do not. It can also be seen from the infrared spectrum that the infrared spectra of MgO / HY catalyst with 5% MgO loading and MgO / HY catalyst with 10% MgO loading are similar to those of acidic HY molecular sieve catalyst, and are significantly different from MgO. Therefore, it is shown that MgO in the loaded MgO molecular sieve catalyst mainly exists inside the pores of the HY molecular sieve, rather than on the outer surface.

Claims

1. A method for catalyzing the synthesis of 3-mercaptopropionic acid using a loaded MgO molecular sieve, characterized in that: The steps include: Step 1, preparing a loaded MgO molecular sieve catalyst: mixing the calcined molecular sieve, magnesium acetate tetrahydrate powder and distilled water in a mass volume ratio of 20.0 g: 0.532-21.28 g: 25 mL to obtain an impregnated solid mixture, and subjecting the solid mixture to programmed temperature calcination to obtain a loaded MgO molecular sieve catalyst with a MgO loading of 0.5-20%; Step 2: Mix the supported MgO molecular sieve catalyst obtained in step 1, acrylic acid and an organic solvent in a certain mass volume ratio, introduce hydrogen sulfide to a certain pressure, heat to a reaction temperature, and react for a certain time to obtain 3-mercaptopropionic acid.

2. The method for synthesizing 3-mercaptopropionic acid by catalysis of a supported MgO molecular sieve according to claim 1, characterized in that: The molecular sieve in step 1 is HY molecular sieve, HZSM5 molecular sieve, HBETA molecular sieve, MCM-41 molecular sieve or SBA-15 molecular sieve.

3. A method for synthesizing 3-mercaptopropionic acid catalyzed by a supported MgO molecular sieve according to claim 1 or 2, characterized in that: The calcination method of the molecular sieve is to increase the temperature from room temperature to 450°C at a heating rate of 5°C / min and calcine at 450°C for 4h.

4. The method for synthesizing 3-mercaptopropionic acid by catalysis of a supported MgO molecular sieve according to claim 3, characterized in that: The programmed temperature rise calcination in step 1 is to heat the material from room temperature to 200°C at a heating rate of 5°C / min, keep the temperature at 200°C for 1 hour, then heat the material to 500°C at a heating rate of 5°C / min, and calcine at 500°C for 5 hours.

5. The method for synthesizing 3-mercaptopropionic acid by catalysis of a supported MgO molecular sieve according to claim 4, characterized in that: In step 2, the mass volume ratio of the supported MgO molecular sieve catalyst, acrylic acid and organic solvent is 0.2-0.5 g:10 mL:50 mL.

6. The method for synthesizing 3-mercaptopropionic acid by catalysis using a supported MgO molecular sieve according to claim 5, characterized in that: The organic solvent in step 2 is a protic solvent or an aprotic solvent.

7. The method for synthesizing 3-mercaptopropionic acid by catalysis of a supported MgO molecular sieve according to claim 6, characterized in that: The protic solvent is an alcohol solvent or an amine solvent; the alcohol solvent is methanol, ethanol, propanol, isopropanol or butanol; the amine solvent is ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, pyrrolidine, N-alkylpyrrolidine, piperidine, N-alkylpiperidine, piperazine, N-alkylpiperazine or morpholine; The aprotic solvent is an ether solvent, an amide solvent, a ketone solvent, a nitrile solvent, pyridine or dimethyl sulfoxide; the ether solvent is diethyl ether, methyl tert-butyl ether, 1,4-dioxane, ethylene glycol monomethyl ether or ethylene glycol dimethyl ether; the amide solvent is N,N-dimethylformamide, N,N-dimethylacetamide, N,N'-diethylformamide or N-methylpyrrolidone; the ketone solvent is acetone, butanone or cyclohexanone; the nitrile solvent is acetonitrile or propionitrile.

8. The method for synthesizing 3-mercaptopropionic acid by catalysis using a supported MgO molecular sieve according to claim 7, characterized in that: In step 2, the reaction temperature is 30-120° C., the pressure of hydrogen sulfide is 0.1-5 MPa, and the reaction time is 1-4 h.

9. The method for synthesizing 3-mercaptopropionic acid by catalysis using a supported MgO molecular sieve according to claim 8, characterized in that: In step 2, the reaction temperature is 40-100° C., and the pressure of hydrogen sulfide is 0.2-4 MPa.

10. The method for synthesizing 3-mercaptopropionic acid by catalysis using a supported MgO molecular sieve according to claim 9, characterized in that: In step 2, the reaction temperature is 50-90° C., and the pressure of hydrogen sulfide is 0.5-2.5 MPa.

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