Method for preparing allyl alcohol and acrylic acid from acrolein

Abstract

The invention belongs to the technical field of organic synthesis, and relates to a method for preparing allyl alcohol and acrylic acid from acrolein, which comprises the following steps: mixing acrolein, an organic base catalyst and a cocatalyst, reacting in a non-polar solvent, and separating and purifying to obtain allyl alcohol and acrylic acid. According to the basic principle of the connizaro reaction, by means of the advantages of the disproportionation reaction, the acrolein serves as a reactant, the organic base catalyst and the cocatalyst are introduced and act together, effective contact between aldehyde group functional groups is promoted, allyl alcohol and acrylic acid with industrial value can be prepared at the same time through a one-step method, and the method is suitable for industrial production. Compared with a traditional method, the method is high in raw material utilization degree, simple in post-treatment, high in operability, small in pollution and suitable for large-scale production.

Description

Technical Field

[0001] The invention relates to the technical field of organic synthesis, in particular to a method for preparing allyl alcohol and acrylic acid from acrolein. Background Art

[0002] Allyl alcohol is an important fine chemical intermediate. Since its molecular structure contains two functional groups, double bonds and hydroxyl groups, it can participate in chemical reactions such as oxidation, reduction, esterification, etherification and addition, and has a wide range of uses in medicine and fragrance. At the same time, in organic synthesis, allyl alcohol is an important organic synthesis raw material for synthesizing products such as epichlorohydrin, glycerol, 1,4-butanediol and allyl ketone. It can also be used to prepare industrial bulk products such as diallyl phthalate (non-volatile crosslinking agent for polyester, etc.), allyl acetate (easy-to-dye fibers, coatings, etc.), allyl butyrate (polyvinyl chloride plasticizer), and allyl acetoacetate (insulating foam plastic fiber treatment agent). Acrylic acid is an important chemical raw material. It generates polyacrylic acid through polymerization reaction and is used in plastics, coatings, rubber, fabrics and other fields. Its derivatives include acrylates, acrylic polymers, etc., which are mainly used in the fields of highly absorbent resin products, detergents, adhesives, building materials, fibers and plastic processing.

[0003] There are four main industrial production methods for allyl alcohol: allyl chloride hydrolysis, propylene oxide isomerization, acrolein reduction, and allyl acetate hydrolysis. Among them, the allyl chloride hydrolysis method was developed the earliest, but because the reaction involves chlorine and is highly toxic, this method has been eliminated. The propylene oxide isomerization method is easy to operate and has high reaction selectivity, but it is greatly affected by the supply of propylene oxide. The acrolein reduction method is to oxidize propylene to produce acrolein, and acrolein is reduced by hydrogenation or hydrogen atom transfer to obtain allyl alcohol. In the allyl acetate hydrolysis method, propylene is acetoxylated to produce allyl acetate, and then allyl alcohol is obtained through hydrolysis or ester exchange.

[0004] The current industrial synthesis methods of acrylic acid mainly include propylene oxidation method, acetate formaldehyde method, and lactic acid (ester) dehydration method. The propylene oxidation method is to oxidize propylene to acrolein, and then oxidize acrolein to acrylic acid. As a non-petroleum production technology, the acetate formaldehyde method uses acetic acid and formaldehyde as raw materials to prepare acrylic acid through aldol condensation reaction. The lactic acid (ester) dehydration method is derived from biomass lactic acid (ester), and acrylic acid is obtained through intramolecular selective catalytic dehydration.

[0005] Although the prior art involves a variety of methods for preparing allyl alcohol and acrylic acid, there is no report on the simultaneous production of industrially valuable allyl alcohol and acrylic acid through a one-step reaction. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a method for preparing allyl alcohol and acrylic acid from acrolein. The present invention is based on the basic principle of the Cannizzaro reaction, takes advantage of the disproportionation reaction, uses acrolein as a reactant, and introduces an organic base catalyst and a co-catalyst, which work together to promote effective contact between aldehyde functional groups, thereby realizing the one-step method for simultaneously preparing allyl alcohol and acrylic acid with industrial value. Compared with the traditional method, the method has high raw material utilization, simple post-treatment, strong operability, low pollution, and is suitable for large-scale production.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] The invention provides a method for preparing allyl alcohol and acrylic acid from acrolein. The method comprises: mixing acrolein, an organic base catalyst and a co-catalyst, reacting in a non-polar solvent, and obtaining allyl alcohol and acrylic acid after separation and purification.

[0009] The reaction is as follows:

[0010]

[0011] The invention is based on the basic principle of the Cannizzaro reaction, takes advantage of the disproportionation reaction, uses acrolein as a reactant, and introduces an organic base catalyst and a co-catalyst, which work together to promote effective contact between aldehyde functional groups, thereby realizing the one-step method for simultaneously preparing allyl alcohol and acrylic acid with industrial value. Since the two exist in different forms in the reaction system (acrylic acid exists in the form of salt), the invention also has the advantages of easy separation and simple post-treatment.

[0012] Compared with traditional methods, this method has high raw material utilization, simple post-processing, strong operability, low pollution, and is suitable for large-scale production.

[0013] Preferably, the organic base catalyst includes any one or a combination of at least two of 1,8-diazabicyclo[5.4.0]undec-7-ene, triethylenediamine, N,N-diisopropylethylamine, triethylamine, N,N-dimethylethylamine or 4-dimethylaminopyridine.

[0014] Preferably, the molar ratio of acrolein to the organic base catalyst is 1:(0.6-5) (for example, it may be 1:0.6, 1:1, 1:2, 1:3, 1:4, 1:5, etc.).

[0015] Preferably, the co-catalyst includes any one of modified montmorillonite, lithium chloride, lithium bromide, lithium phosphate, magnesium bromide or aluminum chloride, or a combination of at least two thereof.

[0016] Preferably, the preparation method of the modified montmorillonite comprises the following steps:

[0017] (1) mixing montmorillonite, a modifier and water, adding alkali to adjust the pH, and obtaining a suspension after stirring;

[0018] (2) The suspension is allowed to stand, and then filtered. The filter cake is washed, dried, ground, and baked to obtain the modified montmorillonite.

[0019] Preferably, in step (1), the modifier includes any one of α-Al2O3, β-Al2O3, zeolite or MgO, or a combination of at least two of them.

[0020] Preferably, in step (1), the mass ratio of the montmorillonite to the modifier is 1:(0.1-0.3) (for example, it can be 1:0.1, 1:0.15, 1:0.2, 1:0.25, 1:0.3, etc.).

[0021] Preferably, in step (1), the pH is adjusted to 10-11 (for example, it can be 10, 10.2, 10.5, 10.8, 11, etc.).

[0022] Preferably, in step (1), the stirring rate is 80-200 rpm (for example, 80 rpm, 100 rpm, 120 rpm, 140 rpm, 160 rpm, 180 rpm, 200 rpm, etc.), and the stirring time is 5-7 h (for example, 5 h, 5.5 h, 6 h, 6.5 h, 7 h, etc.).

[0023] Preferably, in step (2), the suspension is allowed to stand until the suspension is completely settled.

[0024] Preferably, in step (2), the baking temperature is 400-500°C (for example, 400°C, 420°C, 450°C, 480°C, 500°C, etc.), and the baking time is 2.5-3.5h (for example, 2.5h, 2.8h, 3h, 3.2h, 3.5h, etc.).

[0025] Preferably, the mass ratio of acrolein to the promoter is 1:(0.005-0.1) (for example, it may be 1:0.005, 1:0.01, 1:0.02, 1:0.05, 1:0.08, 1:0.1, etc.).

[0026] Preferably, the non-polar solvent includes any one of dichloromethane, dichloroethane, benzene, xylene or toluene, or a combination of at least two thereof.

[0027] Preferably, the reaction apparatus is configured as a Soxhlet extractor.

[0028] Preferably, an inorganic base catalyst is added to the Soxhlet extractor; the inorganic base catalyst includes any one of potassium carbonate, sodium carbonate, sodium bicarbonate, potassium hydroxide, sodium hydroxide, calcium hydroxide or potassium phosphate, or a combination of at least two thereof.

[0029] In the present invention, the boiling point of acrolein is relatively low at 52° C., it is easily volatile and highly irritating during the reaction, which reduces the utilization of raw materials and easily causes environmental pollution. By configuring a Soxhlet extractor, acrolein will generate allyl alcohol and sodium acrylate (with a slow reaction rate) under the action of an inorganic base catalyst, the sodium acrylate solid remains in the Soxhlet extractor, and the allyl alcohol returns to the reaction liquid. Therefore, the configuration of the Soxhlet extractor not only avoids environmental pollution caused by the volatilization of acrolein, but also effectively improves the use efficiency of acrolein.

[0030] Preferably, the molar ratio of acrolein to the inorganic base catalyst is 1:(0.2-3.0) (for example, it can be 1:0.2, 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3.0, etc.).

[0031] Preferably, the method comprises: mixing an organic base catalyst, a co-catalyst and a non-polar solvent to obtain a mixed system; adding acrolein dropwise to the mixed system, and then reacting.

[0032] Preferably, the dropping temperature is ≤20°C (for example, it may be 5°C, 8°C, 10°C, 15°C, 20°C, etc.).

[0033] Preferably, the reaction temperature is 0-100°C (for example, 0°C, 20°C, 40°C, 60°C, 80°C, 100°C, etc.), and the reaction time is 0.5-30h (for example, 0.5h, 1h, 2h, 3h, 5h, 10h, 20h, 30h, etc.).

[0034] Preferably, the separation and purification comprises: filtering the reaction system, distilling and rectifying the filtrate to obtain allyl alcohol; adding acid to the remaining filtrate after distillation to adjust the pH to 1-2 (for example, 1, 1.2, 1.5, 1.8, 2, etc.), filtering again, mixing the filtrate with an inhibitor, and then distilling under reduced pressure to obtain acrylic acid.

[0035] Preferably, the polymerization inhibitor comprises hydroquinone.

[0036] In the present invention, polymerization of acrylic acid during the distillation process can be avoided by adding a polymerization inhibitor, thereby ensuring the yield and purity of the reaction.

[0037] Compared with the prior art, the present invention has at least the following beneficial effects:

[0038] The invention uses acrolein as a starting raw material and can simultaneously obtain allyl alcohol and acrylic acid through a one-step method, thereby realizing the diversified conversion of acrolein. The method has high raw material utilization and good selectivity, and the obtained two products are easy to separate, and the operability is strong, so the method is suitable for large-scale production. DETAILED DESCRIPTION

[0039] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0040] Preparation of modified montmorillonite 1: 50 g of montmorillonite was added to 100 mL of deionized water, 10 g of α-Al2O3 was added thereto, the pH was adjusted to 10-11 using 30% NaOH solution, and the mixture was vigorously stirred at 180 rpm for 6 h to obtain a suspension; the suspension was allowed to stand until it was completely settled, and then filtered. The filter cake was washed with water, washed with alcohol, and dried, and then ground into powder, and baked at 450°C for 3 h to obtain modified montmorillonite 1.

[0041] Preparation of modified montmorillonite 2: Replace the α-Al2O3 in the preparation of modified montmorillonite 1 with an equal amount of zeolite, and keep other steps unchanged to obtain modified montmorillonite 2.

[0042] Other reagents are conventional commercially available products.

[0043] Example 1

[0044] Triethylenediamine (145.8 g, 1.3 eq), modified montmorillonite 1 (1.7 g, 3%) and 80 mL of ethylene dichloride were added to a Soxhlet extractor (12 g) equipped with a thermometer sleeve. NaOH, 0.3eq, mixed evenly with quartz sand) was put into a three-necked flask, and then acrolein (56.0g, 1eq) was slowly added to the reaction system through a constant pressure dropping funnel. During the dropping process, the temperature of the reaction system was ensured to be no higher than 20°C; after the dropping was completed, the reaction was stirred at 55°C for 3h; after the reaction was completed, it was filtered, and the solvent and allyl alcohol were recovered by distillation, and then allyl alcohol with a purity of 98% was obtained by rectification, with a yield of 24.7g and a yield of 85%; then, 2M hydrochloric acid was used to neutralize the remaining filtrate after distillation to pH = 1, acrylic acid was freed, filtered, and an inhibitor hydroquinone was added to the filtrate, and distilled under reduced pressure to obtain acrylic acid with a purity of 99%, a yield of 31.8g and a yield of 88%.

[0045] The characterization data of allyl alcohol are as follows:

[0046] 1H NMR (400MHz, CDCl3) δ6.234-5.586 (m, 1H), 5.320 (d, J = 12Hz, 1H), 5.175 (d, J = 10Hz, 1H), 4.211 (d, J = 8.2Hz, 1H), 2.262 (s, 1H).

[0047] The characterization data of acrylic acid are as follows:

[0048] 1 H NMR (400MHz, DMSO d6) δ12.435(s,1H),6.322(dd,J1=12.4Hz,J2=10.4Hz,1H),6.058(d,J=12.4Hz,1H),5.922(d,J=10.4Hz,1H).

[0049] Example 2

[0050] Triethylenediamine (145.8 g, 1.3 eq), modified montmorillonite 2 (1.7 g, 3%) and 80 mL of ethylene dichloride were added to a Soxhlet extractor (12 g) equipped with a thermometer sleeve. NaOH, 0.3eq, mixed evenly with quartz sand) was put into a three-necked flask, and then acrolein (56.0g, 1eq) was slowly added to the reaction system through a constant pressure dropping funnel. During the dropping process, the temperature of the reaction system was ensured to be no higher than 20°C; after the dropping was completed, the reaction was stirred at 40°C for 3h; after the reaction was completed, it was filtered, and the solvent and allyl alcohol were recovered by distillation, and then allyl alcohol with a purity of 98% was obtained by rectification, with a yield of 20.47g and a yield of 70%; then, 2M hydrochloric acid was used to neutralize the remaining filtrate after distillation to pH = 1, acrylic acid was freed, filtered, and an inhibitor hydroquinone was added to the filtrate, and distilled under reduced pressure to obtain acrylic acid with a purity of 98%, a yield of 28.9g and a yield of 80%.

[0051] Example 3

[0052] Triethylenediamine (145.8 g, 1.3 eq), lithium bromide (1.7 g, 3%) and 80 mL of dichloromethane were added to a three-necked flask with a thermometer sleeve and a Soxhlet extractor (12 g NaOH, 0.3 eq, mixed evenly with quartz sand), and then acrolein (56.0 g, 1 eq) was slowly added to the reaction system through a constant pressure dropping funnel. During the dropping process, the temperature of the reaction system was ensured not to be higher than 20°C. After the dropping was completed, the reaction was stirred at 40°C for 3 hours. After the reaction was completed, the reaction was filtered, and the solvent and allyl alcohol were recovered by distillation. Then, allyl alcohol with a purity of 98% was obtained by rectification, with a yield of 16.9 g and a yield of 58%. Subsequently, the remaining filtrate after distillation was neutralized with 2 M hydrochloric acid to pH = 1, acrylic acid was freed, filtered, and an inhibitor hydroquinone was added to the filtrate, and reduced pressure distillation was performed to obtain acrylic acid with a purity of 98%, a yield of 21.7 g and a yield of 60%.

[0053] Example 4

[0054] Triethylenediamine (145.8 g, 1.1 eq), modified montmorillonite 1 (1.7 g, 3%) and 80 mL of dichloromethane were added to a Soxhlet extractor (12 g) equipped with a thermometer sleeve. NaOH, 0.3eq, mixed evenly with quartz sand) was put into a three-necked flask, and then acrolein (56.0g, 1eq) was slowly added to the reaction system through a constant pressure dropping funnel. During the dropping process, the temperature of the reaction system was ensured to be no higher than 20°C. After the dropping was completed, the reaction was stirred at 40°C for 3h. After the reaction was completed, it was filtered, and the solvent and allyl alcohol were recovered by distillation. Then, allyl alcohol with a purity of 98% was obtained by rectification, with a yield of 25.6g and a yield of 88%. Subsequently, 2M hydrochloric acid was used to neutralize the remaining filtrate after distillation to pH = 1, acrylic acid was freed, and it was filtered. The inhibitor hydroquinone was added to the filtrate, and distilled under reduced pressure to obtain acrylic acid with a purity of 98%, a yield of 32.5g and a yield of 90%.

[0055] Example 5

[0056] Triethylamine (111.4 g, 1.1 eq), modified montmorillonite 1 (1.7 g, 3%) and 80 mL of dichloroethane were added to a Soxhlet extractor (12 g) equipped with a thermometer sleeve. NaOH, 0.3eq, mixed evenly with quartz sand) was put into a three-necked flask, and then acrolein (56.0g, 1eq) was slowly added to the reaction system through a constant pressure dropping funnel. During the dropping process, the temperature of the reaction system was ensured to be no higher than 20°C. After the dropping was completed, the reaction was stirred at 40°C for 3h. After the reaction was completed, it was filtered, and the solvent and allyl alcohol were recovered by distillation. Then, allyl alcohol with a purity of 98% was obtained by rectification, with a yield of 15.4g and a yield of 53% (some products were not separated from triethylamine during distillation). Subsequently, 2M hydrochloric acid was used to neutralize the remaining filtrate after distillation to pH = 1, acrylic acid was freed, and it was filtered. The inhibitor hydroquinone was added to the filtrate, and distilled under reduced pressure to obtain acrylic acid with a purity of 98%, a yield of 22.7g and a yield of 63%.

[0057] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing allyl alcohol and acrylic acid from acrolein, characterized in that: The method comprises: mixing acrolein, an organic base catalyst and a co-catalyst, reacting in a non-polar solvent, and obtaining allyl alcohol and acrylic acid after separation and purification.

2. The method for preparing allyl alcohol and acrylic acid from acrolein according to claim 1, characterized in that: The organic base catalyst includes any one of 1,8-diazabicyclo[5.4.0]undec-7-ene, triethylenediamine, N,N-diisopropylethylamine, triethylamine, N,N-dimethylethylamine or 4-dimethylaminopyridine, or a combination of at least two thereof.

3. The method for preparing allyl alcohol and acrylic acid from acrolein according to claim 1 or 2, characterized in that: The molar ratio of acrolein to the organic base catalyst is 1:(0.6-5).

4. The method for preparing allyl alcohol and acrylic acid from acrolein according to any one of claims 1 to 3, characterized in that: The co-catalyst includes any one of modified montmorillonite, lithium chloride, lithium bromide, lithium phosphate, magnesium bromide or aluminum chloride, or a combination of at least two of them.

5. The method for preparing allyl alcohol and acrylic acid from acrolein according to any one of claims 1 to 4, characterized in that: The mass ratio of acrolein to the co-catalyst is 1:(0.005-0.1).

6. The method for preparing allyl alcohol and acrylic acid from acrolein according to any one of claims 1 to 5, characterized in that: The non-polar solvent includes any one of dichloromethane, dichloroethane, benzene, xylene or toluene, or a combination of at least two thereof.

7. The method for preparing allyl alcohol and acrylic acid from acrolein according to any one of claims 1 to 6, characterized in that: The method comprises: mixing an organic base catalyst, a co-catalyst and a non-polar solvent to obtain a mixed system; dropping acrolein into the mixed system, and then reacting.

8. The method for preparing allyl alcohol and acrylic acid from acrolein according to claim 7, characterized in that: The temperature of the dropping is ≤20°C; Preferably, the reaction temperature is 0-100° C., and the reaction time is 0.5-30 h.

9. The method for preparing allyl alcohol and acrylic acid from acrolein according to claim 1, characterized in that: The separation and purification comprises: filtering the reaction system, distilling and rectifying the filtrate to obtain allyl alcohol; adding acid to the remaining filtrate after distillation to adjust the pH to 1-2, filtering again, mixing the filtrate with a polymerization inhibitor, and then distilling under reduced pressure to obtain acrylic acid.

10. The method for preparing allyl alcohol and acrylic acid from acrolein according to claim 9, characterized in that: The polymerization inhibitor includes hydroquinone.

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