Preparation method of beta-nitrostyrene

Abstract

The invention provides a preparation method of beta-nitrostyrene. The preparation method comprises that benzaldehyde and nitromethane undergo a reaction under the action of a catalyst to produce beta-nitrostyrene, and the catalyst comprises an acetic acid solution of ammonium acetate. The preparation method is simple, the raw materials are cheap and easy to obtain, and the product yield is high.

Description

Technical Field

[0001] The invention relates to the technical field of chemical industry, and in particular to a method for preparing beta-nitrostyrene. Background Art

[0002] β-nitrostyrene can be used as an intermediate to synthesize nitrostyrene compounds, or it can be used directly. Due to the strong electron-withdrawing property of the nitro group in β-nitrostyrene, nitroolefin has obvious electron-deficient characteristics, making it a good dienophile, which can react with various organic compounds such as addition and substitution. At present, the research of β-nitrostyrene compounds at home and abroad is mainly devoted to anti-tumor, sterilization, AIDS, pesticides, rodent-proof and repellent coatings, and prevention of cardiovascular diseases. However, some β-nitrostyrene compound products are not yet mature and therefore cannot be put into use.

[0003] There are two early methods for synthesizing β-nitrostyrene. Method 1: Aromatic aldehyde and nitroalkane are subjected to Henry reaction under alkaline conditions, and then condensed to generate nitrostyrene. This reaction has many side reactions, the product itself polymerizes quickly, is difficult to separate, and is very difficult to post-process, resulting in a relatively low yield of the target product. Method 2: β-nitrostyrene is prepared from olefins, and organic selenium is used to convert inactive olefins into nitroolefin compounds. The yield of method 2 is higher than that of method 1, but the raw materials of method 2 are expensive, and the yield of β-nitrostyrene is not very ideal. Due to the undesirable factors such as expensive raw materials and low target yield in the initial β-nitrostyrene synthesis method, it is still necessary to actively strive to find new synthesis methods to improve experimental efficiency and increase the yield of the target product with low-cost raw materials. Summary of the invention

[0004] In order to solve one of the above technical problems existing in the prior art, the present invention provides a method for preparing β-nitrostyrene, which has simple process, low cost and high product yield.

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

[0006] The invention provides a method for preparing beta-nitrostyrene. The method comprises reacting benzaldehyde and nitromethane under the action of a catalyst to obtain the beta-nitrostyrene, wherein the catalyst comprises an acetic acid solution of ammonium acetate.

[0007] According to some embodiments of the present invention, in the acetic acid solution of ammonium acetate, the mass fraction of ammonium acetate is 20% to 40%, for example, 20%, 25%, 30%, 35%, 40% or any value therebetween, preferably 25% to 35%, more preferably 30% to 40%.

[0008] According to some embodiments of the present invention, the mass ratio of benzaldehyde to ammonium acetate in the catalyst is 1:(0.1-1.0), for example, 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1.0 or any value therebetween, preferably 1:(0.3-1.0). According to some embodiments of the present invention, the mass ratio of benzaldehyde to nitromethane is 1:(0.5-1.0), for example, 1:0.5, 1:0.55, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1.0 or any value therebetween, preferably 1:(0.55-0.7).

[0009] According to some embodiments of the present invention, the reaction is carried out in a first alcohol solvent, preferably methanol. In some embodiments, the mass ratio of benzaldehyde to the first alcohol solvent is 1:(5-15), for example, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:12, 1:15 or any value therebetween, preferably 1:(7-10).

[0010] According to some embodiments of the present invention, the reaction is carried out in the presence of a base. In some embodiments, the base comprises an alkali metal hydroxide, such as sodium hydroxide. In some embodiments, the mass ratio of benzaldehyde to the base is 1:(0.10-0.15), for example, 1:0.1, 1:0.11, 1:0.12, 1:0.13, 1:0.14, 1:0.15.

[0011] According to some embodiments of the present invention, the reaction temperature is -5°C to 0°C. According to some embodiments of the present invention, the reaction time is 1 to 6 hours. In some embodiments, the reaction time is 1 to 3 hours.

[0012] According to some embodiments of the present invention, the method further comprises: after the reaction is completed, mixing the obtained material with hydrochloric acid and performing solid-liquid separation to obtain a crude β-nitrostyrene. In some embodiments, the obtained material is added dropwise to hydrochloric acid. In some embodiments, the mass fraction of hydrogen chloride in the hydrochloric acid is 25% to 38%. In some embodiments, the mass fraction of hydrogen chloride in the hydrochloric acid is 30% to 38%. In some embodiments, the mass ratio of benzaldehyde to hydrochloric acid is 1: (1 to 2), preferably 1: (1 to 1.5).

[0013] According to some embodiments of the present invention, the method further comprises: mixing the crude β-nitrostyrene with a second alcohol solvent, preferably methanol, and heating to dissolve, then adding activated carbon and performing solid-liquid separation to obtain a first liquid phase, and the first liquid phase is vacuum concentrated and cooled to crystallize to obtain the β-nitrostyrene. In some embodiments, the mass of the second alcohol solvent is 5 to 6 times the mass of the crude β-nitrostyrene. In some embodiments, the heating temperature is 55 to 70°C, preferably 60 to 65°C. In some embodiments, vacuum concentration to a solid content of 40% to 50% is followed by cooling to 0 to 5°C for crystallization. In the present invention, the second alcohol solvent is preferably the same as the first alcohol solvent, and more preferably both are methanol.

[0014] According to some embodiments of the present invention, the method further comprises: after cooling and crystallizing, performing solid-liquid separation to obtain a solid phase and a second liquid phase, wherein the solid phase is vacuum dried to obtain a β-nitrostyrene product. In some embodiments, the drying temperature is 40 to 45° C. In the present invention, the second liquid phase can be reused. In some embodiments, the second liquid phase is vacuum concentrated and cooled and crystallized to obtain β-nitrostyrene.

[0015] According to some embodiments of the present invention, the method comprises the following steps:

[0016] After benzaldehyde, nitromethane and an alcohol solvent are mixed, the catalyst is added to obtain a mixed solution, and after the mixed solution is cooled to -5°C to 0°C, an alkali solution is added dropwise to the mixed solution for reaction to obtain β-nitrostyrene.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The method of the present invention improves the yield of beta-nitrostyrene by selecting a suitable catalyst, and the total yield calculated by benzaldehyde is above 86%. The raw materials used in the present invention are cheap and easy to obtain, and the preparation process is simple, which can reduce costs and pollution, is beneficial to industrial production and conforms to the concept of green chemistry. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments. The specific embodiments described herein are only used to explain the present invention and are not intended to constitute any limitation to the present invention.

[0020] The invention provides a method for preparing beta-nitrostyrene. The method comprises reacting benzaldehyde and nitromethane under the action of a catalyst to obtain beta-nitrostyrene, wherein the catalyst comprises an acetic acid solution of ammonium acetate.

[0021] As a specific embodiment, the preparation method of β-nitrostyrene of the present invention comprises the following steps:

[0022] (1) weighing raw materials according to the mass ratio of benzaldehyde:nitromethane:methanol:ammonium acetate=1:(0.5-1.0):(5-15):(0.3-1.0); mixing the raw materials benzaldehyde, nitromethane, and methanol, stirring them uniformly, adding ammonium acetate acetic acid solution, stirring them uniformly, and cooling them to -5°C to 0°C to obtain a mixed solution;

[0023] (2) adding sodium hydroxide solution to the mixed solution dropwise at a temperature of 0-5° C. for about 1-3 hours;

[0024] (3) After the dropwise addition is completed, the reacted material is added dropwise to concentrated hydrochloric acid to separate and obtain crude β-nitrostyrene;

[0025] (4) Add 5-6 times of methanol to the crude β-nitrostyrene according to the mass ratio, heat to 60-65° C. to dissolve, add activated carbon and filter while hot, vacuum concentrate the obtained material to a solid content of 40-50%, then reduce the temperature to 0-5° C. to start crystallization, and separate the wet material and mother liquor; the wet material is vacuum dried at 40-45° C. to obtain the β-nitrostyrene product, and the mother liquor is concentrated, cooled and crystallized for repeated use.

[0026] Furthermore, in step (1), the mass ratio of benzaldehyde:nitromethane:methanol:ammonium acetate is 1:(0.55-0.7):(7.0-10):(0.3-1.0).

[0027] Further, in step (1), the mass fraction of ammonium acetate in the ammonium acetate acetic acid solution is 20% to 40%. Further, in step (1), the mass fraction of ammonium acetate in the ammonium acetate acetic acid solution is 25% to 35%. Further, in step (1), the mass fraction of ammonium acetate in the ammonium acetate acetic acid solution is 30% to 35%.

[0028] Furthermore, in step (2), the mass ratio of benzaldehyde to sodium hydroxide in the sodium hydroxide solution is 1:(0.10-0.15).

[0029] Furthermore, in step (2), the mass fraction of sodium hydroxide in the sodium hydroxide solution is 20% to 40%. Furthermore, in step (2), the mass fraction of sodium hydroxide in the sodium hydroxide solution is 25% to 35%.

[0030] Furthermore, in step (3), the mass fraction of hydrogen chloride in the concentrated hydrochloric acid is 30% to 38%.

[0031] The reagents used in the following experiments of the present invention, unless otherwise specified, are all conventional commercial products or reagents prepared by conventional methods, and the methods used in the experiments, unless otherwise specified, are all conventional experimental methods. The instruments used in the experiments, unless otherwise specified, can all be obtained through commercial channels.

[0032] Example 1

[0033] Take 200kg of benzaldehyde, 115kg of nitromethane and 1500kg of methanol, stir them evenly, then add 200kg of ammonium acetate acetic acid solution with a mass fraction of 30% of ammonium acetate, stir evenly, then start to cool to -5-0°C, then start to drop 80kg of 30% sodium hydroxide solution, the temperature is not higher than 0°C during the dropwise addition, after the dropwise addition is completed, add it back to 30% concentrated hydrochloric acid (260kg), centrifuge to obtain crude β-nitrostyrene, add 5-6 times of methanol according to the mass ratio, heat to 60-65°C to dissolve, add activated carbon and filter while hot, the obtained material is vacuum concentrated to a solid content of 40-50%, then the temperature is reduced to 0-5°C to start crystallization, and the wet material and mother liquor are separated for about 6h, the mother liquor is concentrated and cooled, and the obtained wet material is vacuum dried at 40-45°C to obtain 248.3kg of qualified β-nitrostyrene with a purity of 98.6%, and the total yield is 87.1% calculated based on benzaldehyde.

[0034] Example 2

[0035] Take 200kg of benzaldehyde, 120kg of nitromethane and 1600kg of methanol, stir them evenly, then add 200kg of ammonium acetate acetic acid solution with a mass fraction of 30% of ammonium acetate, stir evenly, then start to cool to -5-0°C, then start to drop 80kg of 30% sodium hydroxide solution, the temperature is not higher than 0°C during the dropwise addition, after the dropwise addition is completed, add it back to 30% concentrated hydrochloric acid (260kg), centrifuge to obtain crude β-nitrostyrene, add 5-6 times of methanol according to the mass ratio, heat to 60-65°C to dissolve, add activated carbon and filter while hot, the obtained material is vacuum concentrated to a solid content of 40-50%, then the temperature is reduced to 0-5°C to start crystallization, and the wet material and mother liquor are separated for about 6h, the mother liquor is concentrated and cooled, and the obtained wet material is vacuum dried at 40-45°C to obtain 249.8kg of qualified β-nitrostyrene with a purity of 98.8%, and the total yield is 87.6% calculated based on benzaldehyde.

[0036] Example 3

[0037] Take 200kg of benzaldehyde, 110kg of nitromethane and 1400kg of methanol, stir them evenly, then add 200kg of ammonium acetate acetic acid solution with a mass fraction of 30% of ammonium acetate, stir evenly, then start to cool to -5-0°C, then start to drop 80kg of 30% sodium hydroxide solution, the temperature is not higher than 0°C during the dropwise addition, after the dropwise addition is completed, add it back to 30% concentrated hydrochloric acid (260kg), centrifuge to obtain crude β-nitrostyrene, add 5-6 times of methanol according to the mass ratio, heat to 60-65°C to dissolve, add activated carbon and filter while hot, the obtained material is vacuum concentrated to a solid content of 40-50%, then the temperature is reduced to 0-5°C to start crystallization, and the wet material and mother liquor are separated for about 6h, the mother liquor is concentrated and cooled, and the obtained wet material is vacuum dried at 40-45°C to obtain 245.6kg of qualified β-nitrostyrene with a purity of 98.6%, and the total yield is 86.1% calculated based on benzaldehyde.

[0038] Example 4

[0039] Take 200kg of benzaldehyde, 115kg of nitromethane and 1500kg of methanol, stir them evenly, then add 200kg of ammonium acetate acetic acid solution with a mass fraction of 20% of ammonium acetate, stir evenly, then start to cool to -5-0°C, then start to drop 80kg of sodium hydroxide solution with a mass fraction of 30%, the temperature is not higher than 0°C during the dropwise addition, after the dropwise addition is completed, add it back to concentrated hydrochloric acid (260kg) with a mass concentration of 30%, centrifuge to obtain crude β-nitrostyrene, add 5-6 times of methanol according to the mass ratio, heat to 60-65°C to dissolve, add activated carbon and filter while hot, the obtained material is vacuum concentrated to a solid content of 40-50%, then the temperature is reduced to 0-5°C to start crystallization, and the wet material and mother liquor are separated for about 6h. The mother liquor is concentrated and cooled, and the obtained wet material is vacuum dried at 40-45°C to obtain 210.6kg of qualified β-nitrostyrene with a purity of 93.5%, and the total yield is 70.1% calculated based on benzaldehyde.

[0040] Example 5

[0041] Take 200kg of benzaldehyde, 115kg of nitromethane and 1500kg of methanol, stir them evenly, then add 200kg of ammonium acetate acetic acid solution with a mass fraction of 40% of ammonium acetate, stir evenly, then start to cool to -5-0°C, then start to drop 80kg of sodium hydroxide solution with a mass fraction of 30%, the temperature is not higher than 0°C during the dropwise addition, after the dropwise addition is completed, add it back to concentrated hydrochloric acid (260kg) with a mass concentration of 30%, centrifuge to obtain crude β-nitrostyrene, add 5-6 times of methanol according to the mass ratio, heat to 60-65°C to dissolve, add activated carbon and filter while hot, the obtained material is vacuum concentrated to a solid content of 40-50%, then the temperature is reduced to 0-5°C to start crystallization, and the wet material and mother liquor are separated for about 6h, the mother liquor is concentrated and cooled, and the obtained wet material is vacuum dried at 40-45°C to obtain 249.3kg of qualified β-nitrostyrene with a purity of 98.8%, and the total yield is 87.6% calculated based on benzaldehyde.

[0042] Comparative Example 1

[0043] Take 200kg of benzaldehyde, 115kg of nitromethane and 1500kg of methanol, stir them evenly, then add 200kg of sodium acetate acetic acid solution with a mass fraction of 30% of sodium acetate, stir evenly, then start to cool to -5-0°C, then start to drop 80kg of 30% sodium hydroxide solution, the temperature is not higher than 0°C during the dropwise addition, after the dropwise addition is completed, add it back to 30% concentrated hydrochloric acid (260kg), centrifuge to obtain crude β-nitrostyrene, add 5-6 times of methanol according to the mass ratio, heat to 60-65°C to dissolve, add activated carbon and filter while hot, the obtained material is vacuum concentrated to a solid content of 40-50%, then the temperature is reduced to 0-5°C to start crystallization, and the wet material and mother liquor are separated for about 6h. The mother liquor is concentrated and cooled, and the obtained wet material is vacuum dried at 40-45°C to obtain 230.6kg of qualified β-nitrostyrene with a purity of 76.3%, and the total yield calculated by benzaldehyde is 62.3%.

[0044] Comparative Example 2

[0045] Take 200kg of benzaldehyde, 115kg of nitromethane and 1500kg of methanol, stir them evenly, then add 200kg of potassium acetate acetic acid solution with a mass fraction of 30% potassium acetate, stir evenly, then start to cool to -5-0°C, then start to drop 80kg of 30% sodium hydroxide solution, the temperature is not higher than 0°C during the dropwise addition, after the dropwise addition is completed, add it back to 30% concentrated hydrochloric acid (260kg), centrifuge to obtain crude β-nitrostyrene, add 5-6 times of methanol according to the mass ratio, heat to 60-65°C to dissolve, add activated carbon and filter while hot, the obtained material is vacuum concentrated to a solid content of 40-50%, then the temperature is reduced to 0-5°C to start crystallization, and the wet material and mother liquor are separated for about 6h, the mother liquor is concentrated and cooled, and the obtained wet material is vacuum dried at 40-45°C to obtain 280.3kg of qualified β-nitrostyrene with a purity of 66.8%, and the total yield calculated based on benzaldehyde is 66.7%.

[0046] Comparative Example 3

[0047] Take 200kg of benzaldehyde, 115kg of nitromethane and 1500kg of methanol, stir them evenly, then add 60kg of ammonium acetate, stir evenly, start cooling to -5-0°C, then start dripping 80kg of 30% sodium hydroxide solution, the temperature is not higher than 0°C during the dripping process, after the dripping is completed, add it back to 30% concentrated hydrochloric acid (260kg), centrifuge to obtain crude β-nitrostyrene, add 5-6 times of methanol according to the mass ratio, heat to 60-65°C to dissolve, add activated carbon and filter while hot, the obtained material is vacuum concentrated to a solid content of 40-50%, then the temperature is reduced to 0-5°C to start crystallization, and the wet material and mother liquor are separated for about 6h. The mother liquor is concentrated and cooled, and the obtained wet material is vacuum dried at 40-45°C to obtain 231.5kg of qualified β-nitrostyrene with a purity of 96.3%, and the total yield is 79.3% calculated based on benzaldehyde.

[0048] Comparative Example 4

[0049] Take 200kg of benzaldehyde, 115kg of nitromethane and 1500kg of methanol, stir them evenly, then add 200kg of 30% ammonium acetate aqueous solution by mass fraction, stir evenly, start cooling to -5-0°C, then start dripping 80kg of 30% sodium hydroxide solution by mass fraction, the temperature is not higher than 0°C during the dripping process, after the dripping is completed, add it back to 30% concentrated hydrochloric acid (260kg), centrifuge to obtain crude β-nitrostyrene, add 5-6 times of methanol according to the mass ratio, heat to 60-65°C to dissolve, add activated carbon and filter while hot, the obtained material is vacuum concentrated to a solid content of 40-50%, then the temperature is reduced to 0-5°C to start crystallization, and the wet material and mother liquor are separated for about 6h. The mother liquor is concentrated and cooled, and the obtained wet material is vacuum dried at 40-45°C to obtain 210kg of qualified β-nitrostyrene with a purity of 63.8%, and the total yield is 47.71% calculated based on benzaldehyde.

[0050] The technical solution of the present invention is not limited to the above-mentioned specific embodiments. All technical variations made according to the technical solution of the present invention fall within the protection scope of the present invention.

Claims

1. A method for preparing β-nitrostyrene, comprising reacting benzaldehyde and nitromethane in the presence of a catalyst to obtain β-nitrostyrene, wherein: The catalyst includes a solution of ammonium acetate in acetic acid.

2. The preparation method according to claim 1, characterized in that: In the acetic acid solution of ammonium acetate, the mass fraction of ammonium acetate is 20% to 40%, preferably 30% to 40%.

3. The preparation method according to claim 1 or 2, characterized in that: The mass ratio of benzaldehyde to ammonium acetate in the catalyst is 1:(0.1-1.0), preferably 1:(0.3-1.0); and / or, The mass ratio of benzaldehyde to nitromethane is 1:(0.5-1.0), preferably 1:(0.55-0.7).

4. The preparation method according to any one of claims 1 to 3, characterized in that: The reaction is carried out in a first alcohol solvent, preferably methanol; preferably, the mass ratio of benzaldehyde to the first alcohol solvent is 1:(5-15), more preferably 1:(7-10).

5. The preparation method according to any one of claims 1 to 4, characterized in that: The reaction is carried out in the presence of a base; Preferably, the base comprises an alkali metal hydroxide, more preferably comprises sodium hydroxide; Preferably, the mass ratio of benzaldehyde to the base is 1:(0.10-0.15).

6. The preparation method according to any one of claims 1 to 5, characterized in that: The reaction temperature is -5°C to 0°C; the reaction time is 1 to 6 hours.

7. The preparation method according to any one of claims 1 to 6, characterized in that: The method further comprises: after the reaction is completed, mixing the obtained material with hydrochloric acid and performing solid-liquid separation to obtain a crude β-nitrostyrene product; Preferably, the mass fraction of hydrogen chloride in the hydrochloric acid is 25% to 38%, preferably 30% to 38%; Preferably, the mass ratio of benzaldehyde to hydrochloric acid is 1:(1-2), preferably 1:(1-1.5).

8. The preparation method according to claim 7, characterized in that: The method further comprises: mixing the crude β-nitrostyrene with a second alcohol solvent, preferably methanol, and heating to dissolve the mixture, then adding activated carbon and performing solid-liquid separation to obtain a first liquid phase, and vacuum concentrating and cooling the first liquid phase to crystallize the β-nitrostyrene; Preferably, the mass of the second alcohol solvent is 5 to 6 times the mass of the crude β-nitrostyrene; Preferably, the heating temperature is 55-70°C, preferably 60-65°C; Preferably, the solution is concentrated in vacuum until the solid content is 40-50% and then cooled to 0-5°C for crystallization.

9. The preparation method according to claim 8, characterized in that: The method further comprises: after crystallization, performing solid-liquid separation to obtain a solid phase and a second liquid phase, wherein the solid phase is vacuum dried to obtain a β-nitrostyrene product; Preferably, the drying temperature is 40-45°C; Preferably, the second liquid phase is concentrated in vacuo and crystallized by cooling to obtain β-nitrostyrene.

10. The preparation method according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: After benzaldehyde, nitromethane and an alcohol solvent are mixed, the catalyst is added to obtain a mixed solution, and after the mixed solution is cooled to -5°C to 0°C, an alkali solution is added dropwise to the mixed solution for reaction to obtain β-nitrostyrene.