A method for synthesizing methyl 3-methoxypropionate with high purity

Abstract

The present invention provides a method for synthesizing high-purity methyl 3-methoxypropionate, belonging to the technical field of organic synthesis. A catalyst, an adsorbent and methanol are mixed and heated, methyl acrylate is added dropwise, the mixture is kept warm and stirred for reaction, cooled to room temperature, the catalyst is separated by a magnet, washed, dried and recycled, the adsorbent is separated by filtration, washed, dried and recycled, and the filtrate is heated and fractionated to obtain methyl 3-methoxypropionate. The methyl 3-methoxypropionate prepared by the present invention is a colorless and transparent solvent, an innovative ether ester functional solvent, non-irritating to the skin, an environmentally friendly green solvent. The preparation method of the present invention is simple, efficient, low-cost and easy to realize industrial production. Among them, the catalyst is easy to separate and recycle, has high catalytic activity, high product yield and few by-products. The adsorbent is used to adsorb heavy metal ions, colloids, organic substances, etc. in the raw materials, greatly improving the purity of the product, and has broad application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of organic synthesis, and particularly relates to a method for synthesizing high-purity methyl 3-methoxypropionate. Background Art

[0002] Methyl 3-methoxypropionate (MMP) is an environmentally friendly solvent of medium volatility. The ether ester group, linear structure, and propionyl group in the molecule endow it with some special properties that other solvents do not have, such as strong solubility, strong polarity, and strong hydrophilicity. It is mainly used as a TFT-LCD photoresist diluent, photoresist remover, stripper, IC cleaning agent, photoresist removal buffer, etchant process, etc. in the production processes of liquid crystal display screens and photoresists, as well as other chemicals with special specifications. At the same time, it is widely used as a solvent for the production of electronic materials. At present, some domestic chemical companies and research institutions have mastered the synthesis method and application technology of methyl 3-methoxypropionate, but there are few reports in the field of environmentally friendly functional solvents for lithium battery manufacturing in China.

[0003] NMP (N-methylpyrrolidone) is classified as a CMR substance (Note: CMR is a triple carcinogen, referring to carcinogenic, mutagenic, and teratogenic). It is a solvent classified as a reproductive toxicant, which means it is toxic to reproduction and may damage the fetus. Therefore, methyl 3-methoxypropionate is expected to completely replace or partially replace the existing mainstream solvent NMP as a supporting solvent for lithium battery cathode binders. Summary of the Invention

[0004] The purpose of the present invention is to propose a method for synthesizing high-purity methyl 3-methoxypropionate, with a simple preparation method, high efficiency, low cost, and easy to realize industrial production. Among them, the catalyst is easy to separate and recycle, has high catalytic activity, high product yield, few by-products, and the adsorbent is used to adsorb heavy metal ions, colloids, organic substances, etc. in the raw materials, greatly improving the purity of the product, and having broad application prospects.

[0005] The technical solution of the present invention is realized as follows:

[0006] The present invention provides a method for synthesizing high-purity methyl 3-methoxypropionate, which mixes a catalyst, an adsorbent, and methanol evenly, heats, drops methyl acrylate, keeps warm and stirs for reaction, cools to room temperature, separates the catalyst by a magnet, washes, dries, and recycles it, filters and separates the adsorbent, washes, dries, and recycles it, and heats and fractionates the filtrate to obtain methyl 3-methoxypropionate.

[0007] As a further improvement of the present invention, the molar ratio of methanol to methyl acrylate is 1.1 - 1.4:1, the temperature is heated to 50 - 60 °C, the time for holding and stirring the reaction is 2 - 4 h, the addition amount of the catalyst is 0.5 - 1 wt% of the total mass of the system, and the addition amount of the adsorbent is 2 - 3 wt% of the total mass of the system.

[0008] As a further improvement of the present invention, the preparation method of the catalyst is as follows:

[0009] S1. Dissolve ferric chloride, aluminum chloride, and magnesium chloride in water to obtain solution A; use ammonia water as solution B; ultrasonically disperse magnetic iron oxide in water, heat, and simultaneously dropwise add solution A and solution B, adjust the pH value of the solution, hold and stir the reaction, age, filter, and collect the precipitate to obtain Fe3O4@FeAlMg-LDH;

[0010] S2. Dissolve nickel nitrate and ammonium molybdate in water, add Fe3O4@FeAlMg-LDH, carry out a hydrothermal reaction, cool to room temperature, separate by a magnet, wash, and dry to obtain NiMoO4 / Fe3O4@FeAlMg-LDH;

[0011] S3. Add potassium nitrate and NiMoO4 / Fe3O4@FeAlMg-LDH to water, ultrasonically disperse evenly, dry, and calcine to obtain the catalyst.

[0012] As a further improvement of the present invention, in step S1, the mass ratio of ferric chloride, aluminum chloride, magnesium chloride, and magnetic iron oxide is 0.6 - 0.8:3 - 5:2 - 3:0.4 - 0.6, the temperature is heated to 60 - 70 °C, the pH value of the solution is adjusted to 9 - 10, the time for holding and stirring the reaction is 2 - 4 h, and the aging time is 20 - 24 h.

[0013] As a further improvement of the present invention, in step S2, the mass ratio of nickel nitrate, ammonium molybdate, and Fe3O4@FeAlMg-LDH is 3 - 5:1:5 - 7, the temperature of the hydrothermal reaction is 140 - 160 °C, and the time is 6 - 8 h.

[0014] As a further improvement of the present invention, in step S3, the mass ratio of potassium nitrate and NiMoO4 / Fe3O4@FeAlMg-LDH is 2 - 3:10, the calcination temperature is 550 - 650 °C, and the time is 3 - 5 h.

[0015] As a further improvement of the present invention, the preparation method of the adsorbent is as follows:

[0016] T1. Add silica powder to water, add tannic acid and a catalyst, heat and stir the reaction, centrifuge, wash, and dry to obtain modified silica;

[0017] T2. Add the modified silica into water, add NHS and EDC, stir for activation, add silk fibroin peptide, stir for reaction, centrifuge, wash, and dry to obtain silk fibroin peptide@silica;

[0018] T3. Add silk fibroin peptide@silica, phytic acid, β-cyclodextrin, and sodium dihydrogen phosphate into water, perform hydrothermal reaction, centrifuge, add the product into an alkali solution and stir for reaction, centrifuge, wash, and dry to obtain the adsorbent.

[0019] As a further improvement of the present invention, in step T1, the average particle size of the silica powder is 10 - 20 μm, the mass ratio of the silica powder, tannic acid, and the catalyst is 10:3 - 4:0.5 - 1, the catalyst is a Tris-HCl solution with pH = 8.5 - 9.5, the temperature of the heating and stirring reaction is 45 - 55 °C, and the time is 2 - 4 h.

[0020] As a further improvement of the present invention, in step T2, the mass ratio of the modified silica, NHS, EDC, and silk fibroin peptide is 10:3 - 4:2 - 3:7 - 10, the stirring activation time is 30 - 40 min, and the stirring reaction time is 5 - 7 h.

[0021] As a further improvement of the present invention, in step T3, the mass ratio of silk fibroin peptide@silica, phytic acid, β-cyclodextrin, and sodium dihydrogen phosphate is 10:4 - 6:5 - 7:1 - 2, the temperature of the hydrothermal reaction is 140 - 160 °C, the time is 5 - 7 h, the alkali solution is a 10 - 15 wt% NaOH or KOH solution, and the stirring reaction time is 1 - 2 h.

[0022] The present invention has the following beneficial effects:

[0023] The methyl 3-methoxypropionate prepared by the present invention is a colorless and transparent solvent, an innovative ether ester functional solvent, non-irritating to the skin, an environmentally friendly green solvent. The preparation method of the present invention is simple, efficient, low-cost, and easy to realize industrial production. Among them, the catalyst is easy to separate and recycle, has high catalytic activity, high product yield, few by-products, and the adsorbent is used to adsorb heavy metal ions, colloids, organic substances, etc. in the raw materials, greatly improving the purity of the product, and has broad application prospects.

[0024] The present invention prepares a catalyst. Using metal layered hydroxide as a carrier, magnetic iron tetroxide is in-situ loaded, enabling the catalyst to have good ferromagnetism and facilitating magnetic separation, thus facilitating separation from the adsorbent, recycling, and reuse. Nickel molybdate is in-situ grown by the hydrothermal method. The Fe3O4@FeAlMg-LDH carrier provides a large specific surface area and abundant catalytic active sites, so that the prepared NiMoO4 / Fe3O4@FeAlMg-LDH has a large reaction specific surface area, abundant active sites, and excellent electron transport performance. Finally, potassium nitrate is used as a precursor to be impregnated and loaded on NiMoO4 / Fe3O4@FeAlMg-LDH, which has good reaction activity, and the active component has good firmness, is not easy to lose K, and can maintain high activity during long-term and multiple reactions.

[0025] The present invention prepares an adsorbent. Using silica as a carrier, tannic acid is surface-loaded, making the silica surface carry abundant carboxyl groups, thus facilitating coupling with silk fibroin peptide, providing abundant hydroxyl and amino groups. Through bridging with phytic acid and β-cyclodextrin, the adsorbent surface is provided with abundant active groups such as carboxyl, hydroxyl, amino, and phosphate groups, which can have excellent adsorption and fixation ability for heavy metal ions, colloids, etc., and also has a large number of cavities for good fixation of organic substances, thus greatly purifying the raw materials, and the purity of the prepared methyl 3-methoxypropionate is significantly improved. Specific Embodiments

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0027] The average particle size of the silica powder is 10 - 20 μm, and it is purchased from Hebei Ruihuang Metal Materials Co., Ltd.

[0028] Preparation Example 1 Preparation of the Catalyst

[0029] The method is as follows:

[0030] S1. Dissolve 0.6 g of ferric chloride, 3 g of aluminum chloride, and 2 g of magnesium chloride in 100 mL of water to obtain Solution A; use 5 wt% ammonia water as Solution B; add 0.4 g of magnetic iron tetroxide to 100 mL of water, disperse it by ultrasonic wave at 1000 W for 10 min, heat to 60 °C, and simultaneously dropwise add Solution A and Solution B, adjust the pH value of the solution to 9, keep stirring and reacting for 2 h, age for 20 h, filter, and collect the precipitate to obtain Fe3O4@FeAlMg-LDH;

[0031] S2. Dissolve 3 g of nickel nitrate and 1 g of ammonium molybdate in 100 mL of water, add 5 g of Fe3O4@FeAlMg-LDH, perform hydrothermal reaction at 140 °C for 6 h, cool to room temperature, separate by magnet, wash, and dry to obtain NiMoO4 / Fe3O4@FeAlMg-LDH;

[0032] S3. Add 2 g of potassium nitrate and 10 g of NiMoO4 / Fe3O4@FeAlMg-LDH to 100 mL of water, disperse ultrasonically at 1000 W for 15 min, dry, and calcine at 550 °C for 3 h to obtain the catalyst.

[0033] Preparation Example 2 Preparation of the catalyst

[0034] The method is as follows:

[0035] S1. Dissolve 0.8 g of ferric chloride, 5 g of aluminum chloride, and 3 g of magnesium chloride in 100 mL of water to obtain solution A; use 7 wt% ammonia water as solution B; add 0.6 g of magnetic iron oxide to 100 mL of water, disperse ultrasonically at 1000 W for 10 min, heat to 70 °C, and simultaneously add solution A and solution B dropwise, adjust the pH value of the solution to 10, keep warm and stir for reaction for 4 h, age for 24 h, filter, collect the precipitate, and obtain Fe3O4@FeAlMg-LDH;

[0036] S2. Dissolve 5 g of nickel nitrate and 1 g of ammonium molybdate in 100 mL of water, add 7 g of Fe3O4@FeAlMg-LDH, perform hydrothermal reaction at 160 °C for 8 h, cool to room temperature, separate by magnet, wash, and dry to obtain NiMoO4 / Fe3O4@FeAlMg-LDH;

[0037] S3. Add 3 g of potassium nitrate and 10 g of NiMoO4 / Fe3O4@FeAlMg-LDH to 100 mL of water, disperse ultrasonically at 1000 W for 15 min, dry, and calcine at 650 °C for 5 h to obtain the catalyst.

[0038] Preparation Example 3 Preparation of the catalyst

[0039] The method is as follows:

[0040] S1. Dissolve 0.7 g of ferric chloride, 4 g of aluminum chloride, and 2.5 g of magnesium chloride in 100 mL of water to obtain solution A; use 6 wt% ammonia water as solution B; add 0.5 g of magnetic iron oxide to 100 mL of water, disperse ultrasonically at 1000 W for 10 min, heat to 65 °C, and simultaneously add solution A and solution B dropwise, adjust the pH value of the solution to 9.5, keep warm and stir for reaction for 3 h, age for 22 h, filter, collect the precipitate, and obtain Fe3O4@FeAlMg-LDH;

[0041] S2. Dissolve 4 g of nickel nitrate and 1 g of ammonium molybdate in 100 mL of water, add 6 g of Fe3O4@FeAlMg-LDH, carry out hydrothermal reaction at 150 °C for 7 h, cool to room temperature, separate by a magnet, wash, and dry to obtain NiMoO4 / Fe3O4@FeAlMg-LDH;

[0042] S3. Add 2.5 g of potassium nitrate and 10 g of NiMoO4 / Fe3O4@FeAlMg-LDH to 100 mL of water, disperse ultrasonically at 1000 W for 15 min, dry, and calcine at 600 °C for 4 h to obtain the catalyst.

[0043] Comparative Preparation Example 1

[0044] Compared with Preparation Example 3, the difference lies in that step S2 is not carried out.

[0045] Specifically as follows:

[0046] S1. Dissolve 0.7 g of ferric chloride, 4 g of aluminum chloride, and 2.5 g of magnesium chloride in 100 mL of water to obtain solution A; use 6 wt% ammonia water as solution B; add 0.5 g of magnetic iron oxide to 100 mL of water, disperse ultrasonically at 1000 W for 10 min, heat to 65 °C, and simultaneously add solution A and solution B dropwise, adjust the pH value of the solution to 9.5, keep stirring and reacting for 3 h, age for 22 h, filter, collect the precipitate, and obtain Fe3O4@FeAlMg-LDH;

[0047] S2. Add 2.5 g of potassium nitrate and 10 g of Fe3O4@FeAlMg-LDH to 100 mL of water, disperse ultrasonically at 1000 W for 15 min, dry, and calcine at 600 °C for 4 h to obtain the catalyst.

[0048] Comparative Preparation Example 2

[0049] Compared with Preparation Example 3, the difference lies in that step S3 is not carried out.

[0050] Specifically as follows:

[0051] S1. Dissolve 0.7 g of ferric chloride, 4 g of aluminum chloride, and 2.5 g of magnesium chloride in 100 mL of water to obtain solution A; use 6 wt% ammonia water as solution B; add 0.5 g of magnetic iron oxide to 100 mL of water, disperse ultrasonically at 1000 W for 10 min, heat to 65 °C, and simultaneously add solution A and solution B dropwise, adjust the pH value of the solution to 9.5, keep stirring and reacting for 3 h, age for 22 h, filter, collect the precipitate, and obtain Fe3O4@FeAlMg-LDH;

[0052] S2. Dissolve 4 g of nickel nitrate and 1 g of ammonium molybdate in 100 mL of water. Add 6 g of Fe3O4@FeAlMg-LDH, and conduct a hydrothermal reaction at 150 °C for 7 h. Cool to room temperature, separate by a magnet, wash, and dry to obtain NiMoO4 / Fe3O4@FeAlMg-LDH, which is the catalyst.

[0053] Test Example 1

[0054] The specific surface area and pore structure of the catalysts prepared in Preparation Examples 1-3 of the present invention and Comparative Preparation Examples 1-2 were tested using an ASAP2400 static nitrogen adsorption instrument from Micromeritics, USA. The results are shown in Table 1.

[0055] Table 1

[0056] Group <![CDATA[Specific surface area (m 2 / g)]]> <![CDATA[Pore volume (cm 3 / g)]]> Preparation Example 1 605 0.578 Preparation Example 2 607 0.580 Preparation Example 3 610 0.584 Comparative Preparation Example 1 549 0.510 Comparative Preparation Example 2 568 0.535

[0057] As can be seen from the above table, the catalysts prepared in Preparation Examples 1-3 of the present invention have a larger specific surface area and pore volume.

[0058] Preparation Example 4 Preparation of Adsorbent

[0059] The method is as follows:

[0060] T1. Add 10 g of silica powder to 200 mL of water, add 3 g of tannic acid and 0.5 g of catalyst, heat to 45 °C, stir and react for 2 h, centrifuge, wash, and dry to obtain modified silica;

[0061] The catalyst is a Tris-HCl solution with a pH of 8.5;

[0062] T2. Add 10 g of modified silica to 200 mL of water, add 3 g of NHS and 2 g of EDC, stir and activate for 30 min, add 7 g of silk fibroin peptide, stir and react for 5 h, centrifuge, wash, and dry to obtain silk fibroin peptide@silica;

[0063] T3. Add 10 g of silk fibroin peptide@silica, 4 g of phytic acid, 5 g of β-cyclodextrin, and 1 g of sodium dihydrogen phosphate to 200 mL of water, conduct a hydrothermal reaction at 140 °C for 5 h, centrifuge, add the product to a 10 wt% NaOH solution and stir and react for 1 h, centrifuge, wash, and dry to obtain the adsorbent.

[0064] Preparation Example 5 Preparation of Adsorbent

[0065] The method is as follows:

[0066] T1. Add 10 g of silica powder to 200 mL of water, add 4 g of tannic acid and 1 g of catalyst, heat to 55 °C, stir and react for 4 h, centrifuge, wash, and dry to obtain modified silica;

[0067] The catalyst is a Tris-HCl solution with a pH of 9.5;

[0068] T2. Add 10 g of modified silica to 200 mL of water, add 4 g of NHS and 3 g of EDC, stir and activate for 40 min, add 10 g of silk fibroin peptide, stir and react for 7 h, centrifuge, wash, and dry to obtain silk fibroin peptide@silica;

[0069] T3. Add 10 g of silk fibroin peptide@silica, 6 g of phytic acid, 7 g of β-cyclodextrin, and 2 g of sodium dihydrogen phosphate to 200 mL of water, perform a hydrothermal reaction at 160 °C for 7 h, centrifuge, add the product to a 15 wt% KOH solution, stir and react for 2 h, centrifuge, wash, and dry to obtain the adsorbent.

[0070] Preparation Example 6 Preparation of the adsorbent

[0071] The method is as follows:

[0072] T1. Add 10 g of silica powder to 200 mL of water, add 3.5 g of tannic acid and 0.7 g of the catalyst, heat to 50 °C, stir and react for 3 h, centrifuge, wash, and dry to obtain modified silica;

[0073] The catalyst is a Tris-HCl solution with a pH of 9;

[0074] T2. Add 10 g of modified silica to 200 mL of water, add 3.5 g of NHS and 2.4 g of EDC, stir and activate for 35 min, add 8.6 g of silk fibroin peptide, stir and react for 6 h, centrifuge, wash, and dry to obtain silk fibroin peptide@silica;

[0075] T3. Add 10 g of silk fibroin peptide@silica, 5 g of phytic acid, 6 g of β-cyclodextrin, and 1.4 g of sodium dihydrogen phosphate to 200 mL of water, perform a hydrothermal reaction at 150 °C for 6 h, centrifuge, add the product to a 12 wt% NaOH solution, stir and react for 1.5 h, centrifuge, wash, and dry to obtain the adsorbent.

[0076] Comparative Preparation Example 3

[0077] Compared with Preparation Example 6, the difference is that step T3 is not carried out.

[0078] Specifically as follows:

[0079] T1. Add 10 g of silica powder to 200 mL of water, add 3.5 g of tannic acid and 0.7 g of the catalyst, heat to 50 °C, stir and react for 3 h, centrifuge, wash, and dry to obtain modified silica;

[0080] The catalyst is a Tris-HCl solution with a pH of 9;

[0081] T2. Add 10 g of modified silica to 200 mL of water, add 3.5 g of NHS and 2.4 g of EDC, stir and activate for 35 min, add 8.6 g of silk fibroin peptide, stir and react for 6 h, centrifuge, wash, and dry to obtain silk fibroin peptide@silica, which is the adsorbent.

[0082] Comparative Preparation Example 4

[0083] Compared with Preparation Example 6, the difference lies in that steps T2 and T3 are not carried out.

[0084] Specifically as follows:

[0085] T1. Add 10 g of silica powder to 200 mL of water, add 3.5 g of tannic acid and 0.7 g of catalyst, heat to 50 °C, stir and react for 3 h, centrifuge, wash, and dry to obtain modified silica, which is the adsorbent;

[0086] The catalyst is a Tris-HCl solution with a pH of 9.

[0087] Test Example 2

[0088] The specific surface area and pore structure of the adsorbents prepared in Preparation Examples 4-6 of the present invention and Comparative Preparation Examples 2-4 were tested using an ASAP2400 static nitrogen adsorption instrument from Micromeritics, USA. The results are shown in Table 2.

[0089] Table 2

[0090] Group <![CDATA[Specific surface area (m 2 / g)]]> <![CDATA[Pore volume (cm 3 / g)]]> Preparation Example 4 657 0.612 Preparation Example 5 653 0.610 Preparation Example 6 660 0.615 Comparative Preparation Example 3 603 0.587 Comparative Preparation Example 4 537 0.502

[0091] As can be seen from the above table, the adsorbents prepared in Preparation Examples 4-6 of the present invention have a large specific surface area and pore volume.

[0092] Example 1

[0093] This example provides a method for synthesizing high-purity methyl 3-methoxypropionate. Mix the catalyst prepared in Preparation Example 1, the adsorbent prepared in Preparation Example 4, and methanol evenly. The addition amount of the catalyst is 0.5 wt% of the total mass of the system, and the addition amount of the adsorbent is 2 wt% of the total mass of the system. Heat to 50 °C, dropwise add methyl acrylate, and the molar ratio of methanol to methyl acrylate is 1.1:1. Keep warm and stir and react for 2 h, cool to room temperature, separate the catalyst by magnet, wash, dry, and recycle it. Filter and separate the adsorbent, wash, dry, and recycle it. Heat and fractionate the filtrate to obtain methyl 3-methoxypropionate.

[0094] Example 2

[0095] This embodiment provides a method for synthesizing high-purity methyl 3-methoxypropionate. The catalyst prepared in Preparation Example 2, the adsorbent prepared in Preparation Example 5 and methanol are mixed evenly. The addition amount of the catalyst is 1 wt% of the total mass of the system, and the addition amount of the adsorbent is 3 wt% of the total mass of the system. Heat to 60 °C, and dropwise add methyl acrylate. The molar ratio of methanol to methyl acrylate is 1.4:1. Keep warm and stir for reaction for 4 h, cool to room temperature, separate the catalyst by magnet, wash, dry, recycle, filter and separate the adsorbent, wash, dry, recycle, heat and fractionate the filtrate to obtain methyl 3-methoxypropionate.

[0096] Example 3

[0097] This embodiment provides a method for synthesizing high-purity methyl 3-methoxypropionate. The catalyst prepared in Preparation Example 3, the adsorbent prepared in Preparation Example 6 and methanol are mixed evenly. The addition amount of the catalyst is 0.7 wt% of the total mass of the system, and the addition amount of the adsorbent is 2.5 wt% of the total mass of the system. Heat to 55 °C, and dropwise add methyl acrylate. The molar ratio of methanol to methyl acrylate is 1.25:1. Keep warm and stir for reaction for 3 h, cool to room temperature, separate the catalyst by magnet, wash, dry, recycle, filter and separate the adsorbent, wash, dry, recycle, heat and fractionate the filtrate to obtain methyl 3-methoxypropionate.

[0098] Comparative Example 1

[0099] Compared with Example 3, the difference is that the catalyst is prepared from Comparative Preparation Example 1.

[0100] Comparative Example 2

[0101] Compared with Example 3, the difference is that the catalyst is prepared from Comparative Preparation Example 2.

[0102] Comparative Example 3

[0103] Compared with Example 3, the difference is that the adsorbent is prepared from Comparative Preparation Example 3.

[0104] Comparative Example 4

[0105] Compared with Example 3, the difference is that the adsorbent is prepared from Comparative Preparation Example 4.

[0106] Comparative Example 5

[0107] Compared with Example 3, the difference is that no adsorbent is added.

[0108] Test Example 3

[0109] Evaluate the reactions in Examples 1-3 and Comparative Examples 1-3, and the results are shown in Table 3.

[0110] Table 3

[0111] Group Yield of methyl 3-methoxypropionate (%) Purity of methyl 3-methoxypropionate (%) Example 1 99.992 >99.999 Example 2 99.990 >99.999 Example 3 99.997 >99.999 Comparative Example 1 96.124 99.015 Comparative Example 2 91.295 99.242 Comparative Example 3 99.912 97.455 Comparative Example 4 99.906 95.782 Comparative Example 5 99.824 89.045

[0112] As can be seen from the above table, the methods in Examples 1-3 of the present invention can obtain methyl 3-methoxypropionate with high purity and high reaction yield.

[0113] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for synthesizing methyl 3-methoxypropionate with high purity, characterized in that, Mix the catalyst, adsorbent, and methanol evenly, heat, add methyl acrylate dropwise, keep the temperature and stir to react, cool to room temperature, separate the catalyst by magnet, wash, dry, recycle, filter to separate the adsorbent, wash, dry, recycle, heat and fractionate the filtrate to obtain methyl 3-methoxypropionate; The preparation method of the catalyst is as follows: S1. Dissolve ferric chloride, aluminum chloride, and magnesium chloride in water to obtain solution A; use ammonia water as solution B; ultrasonically disperse magnetic iron tetroxide in water, heat, and simultaneously add solution A and solution B dropwise, adjust the pH value of the solution, keep the temperature and stir to react, age, filter, and collect the precipitate to obtain Fe3O4@FeAlMg-LDH; S2. Dissolve nickel nitrate and ammonium molybdate in water, add Fe3O4@FeAlMg-LDH, perform hydrothermal reaction, cool to room temperature, separate by magnet, wash, and dry to obtain NiMoO4 / Fe3O4@FeAlMg-LDH; S3. Add potassium nitrate and NiMoO4 / Fe3O4@FeAlMg-LDH to water, ultrasonically disperse evenly, dry, and calcine to obtain the catalyst; The preparation method of the adsorbent is as follows: T1. Add silica powder to water, add tannic acid and catalyst, heat and stir to react, centrifuge, wash, and dry to obtain modified silica; T2. Add the modified silica to water, add NHS and EDC, stir to activate, add silk fibroin peptide, stir to react, centrifuge, wash, and dry to obtain silk fibroin peptide@silica; T3. Add silk fibroin peptide@silica, phytic acid, β-cyclodextrin, and sodium dihydrogen phosphate to water, perform hydrothermal reaction, centrifuge, add the product to an alkali solution and stir to react, centrifuge, wash, and dry to obtain the adsorbent.

2. The synthesis method according to claim 1, wherein The molar ratio of methanol to methyl acrylate is 1.1-1.4:1, the heating temperature is 50-60°C, the time for keeping the temperature and stirring to react is 2-4 h, the addition amount of the catalyst is 0.5-1 wt% of the total mass of the system, and the addition amount of the adsorbent is 2-3 wt% of the total mass of the system.

3. The high-purity synthesis method according to claim 1, characterized in that In step S1, the mass ratio of ferric chloride, aluminum chloride, magnesium chloride, and magnetic iron tetroxide is 0.6-0.8:3-5:2-3:0.4-0.6, the heating temperature is 60-70°C, the pH value of the solution is adjusted to 9-10, the time for keeping the temperature and stirring to react is 2-4 h, and the aging time is 20-24 h.

4. The high-purity synthesis method according to claim 1, characterized in that, In step S2, the mass ratio of nickel nitrate, ammonium molybdate, and Fe3O4@FeAlMg-LDH is 3-5:1:5-7, the temperature of the hydrothermal reaction is 140-160°C, and the time is 6-8 h.

5. The high-purity synthesis method according to claim 1, characterized in that, In step S3, the mass ratio of potassium nitrate and NiMoO4 / Fe3O4@FeAlMg-LDH is 2-3:10, the calcination temperature is 550-650°C, and the time is 3-5 h.

6. The high-purity synthesis method according to claim 1, characterized in that, The average particle size of the silica powder described in step T1 is 10 - 20 μm. The mass ratio of the silica powder, tannic acid and the catalyst is 10:3 - 4:0.5 - 1. The catalyst is a Tris-HCl solution with pH = 8.5 - 9.

5. The temperature of the heating and stirring reaction is 45 - 55 °C, and the time is 2 - 4 h.

7. The high-purity synthesis method according to claim 1, characterized in that, The mass ratio of the modified silica, NHS, EDC and silk fibroin peptide described in step T2 is 10:3 - 4:2 - 3:7 - 10. The time of the stirring activation is 30 - 40 min, and the time of the stirring reaction is 5 - 7 h.

8. The high-purity synthesis method according to claim 1, characterized in that, The mass ratio of the silk fibroin peptide@silica, phytic acid, β-cyclodextrin, sodium dihydrogen phosphate described in step T3 is 10:4 - 6:5 - 7:1 - 2. The temperature of the hydrothermal reaction is 140 - 160 °C, and the time is 5 - 7 h. The alkali solution is a 10 - 15 wt% NaOH or KOH solution, and the time of the stirring reaction is 1 - 2 h.