A kind of synthetic method of butanone alcohol

Abstract

The invention discloses a method for synthesizing butanone alcohol, comprising the following steps: (1) treating the recovered acetone with a glycolipid biosurfactant, and then obtaining treated acetone through separation; (2) passing the treated acetone and formaldehyde into a pipeline reactor, and reacting under supercritical conditions to obtain the butanone alcohol. The synthesis method reduces the butanone by-product generated in the existing synthesis method, and solves the problem of equipment clogging due to polymerization of the butanone by-product.

Description

Technical Field

[0001] The invention belongs to the field of organic synthesis, and particularly relates to a method for synthesizing butanone alcohol. Background Art

[0002] Butanone alcohol, also known as 4-hydroxy-2-butanone, is an important raw material for the pharmaceutical industry and other fine organic synthesis industries. After dehydration, methyl vinyl ketone is obtained for the synthesis of hexyl alcohol, which is an important intermediate for the synthesis of vitamin A. It can also react with phenol to synthesize raspberry ketone, a warm-scented fragrance with an elegant fruity aroma. After adding a suitable catalyst, it can synthesize an important chemical raw material (R)-1,3-butanediol, which can be used to synthesize optical compounds such as azetidinone, which is an intermediate raw material for the synthesis of penicillin antibiotics, pheromones, fragrances and pesticides. In industry, it is mostly prepared by the aldol condensation reaction of acetone and formaldehyde catalyzed by strong bases such as NaOH and KOH, but formaldehyde is prone to polymerization under base catalysis, and the resulting yellow polymer is easy to clog the equipment.

[0003] Patent CN110105187A discloses a production method for preparing butanone alcohol by oxidizing 1,3-butanediol with hydrogen peroxide, using sodium tungstate as a catalyst, tetrabutylammonium chloride as an auxiliary agent, diisopropyl ether as a water-carrying agent. However, 1,3-butanediol has poor water solubility and cannot participate in the reaction well during the reaction, resulting in a low conversion rate. In addition, auxiliary agents and water-carrying agents need to be added, resulting in a long subsequent separation process and high energy consumption.

[0004] Patent CN112062664B discloses that amino acids are used as catalysts to catalyze the reaction of formaldehyde and acetone in a non-protonic polar solvent at room temperature for 20h to 25h to obtain butanone alcohol. Among them, the molar ratio of formaldehyde, amino acid and acetone feed is 1:1 to 15, and the yield is 91%-92.3%. Patent CN109809976B discloses that formaldehyde solution and acetone are reacted in a weight ratio of 1:30 to obtain butanone alcohol. Patent CN1120831C discloses a method for synthesizing butanone alcohol using alkaline anion exchange resin, but the macroporous or gel-type weakly alkaline anion exchange resin used is easily deactivated and has low catalytic activity. At the same time, this method increases the conversion rate of formaldehyde by increasing the feed ratio of acetone to formaldehyde, but excess acetone will condense to form diacetone alcohol byproduct.

[0005] In order to overcome the defects of the above method, patent CN109516906B adopts catalytic reaction distillation technology to reduce the feed molar ratio of acetone to formaldehyde to 1.5:1~4:1, but requires the temperature of the catalytic reaction section to be 70~100°C, so that the catalytic distillation tower must be operated under pressure, the bottom temperature of the tower is high, and excess acetone is prone to side reactions.

[0006] In view of the various drawbacks of the aldol condensation of acetone and formaldehyde under alkaline conditions, Huang Guodong et al. reported in Guangzhou Chemical Industry (Volume 41, Journal 16, 2013) that supercritical acetone was used as both a reaction solvent and a reactant to react with formaldehyde under non-catalyst conditions to synthesize butanone alcohol in one step, with a formaldehyde conversion rate of 100%. This method does not introduce an alkaline catalyst, has few side reactions, simple process steps, is more conducive to product purification, has the advantages of green energy saving and environmental protection, and is expected to become a new process for the green synthesis of butanone alcohol. The acetone used in this reaction is in excess relative to formaldehyde, and after the reaction is completed, it is generally applied by direct evaporation. However, we found that butenone will be generated when the acetone used directly is used to synthesize butanone alcohol in supercritical conditions. Butenone with double bonds is more active and prone to polymerization, which may block the equipment or pipelines of the acetone circulation system and butanone alcohol distillation system.

[0007] Therefore, it is urgent to develop a green and efficient method for synthesizing butanone alcohol. Inspired by the supercritical butanone alcohol reaction, the present invention provides a method for synthesizing butanone alcohol, which uses recycled acetone as a raw material and applies pretreatment technology to obtain a butanone alcohol product with high conversion rate and high selectivity under supercritical conditions, which has positive promotion significance. Summary of the invention

[0008] In view of the defects of butanone alcohol synthesis in the prior art, the present invention provides a green process for synthesizing butanone alcohol under supercritical conditions, which not only solves the environmental problem caused by excessive acetone in the synthesis process of butanone alcohol, butanone alcohol yield is improved, the production of side product butenone is suppressed, and the equipment blockage problem caused by its polymerization is solved, which is conducive to the industrialized large-scale production of butanone alcohol.

[0009] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0010] A method for synthesizing butanone alcohol comprises the following steps:

[0011] (1) The recovered acetone is activated and pretreated using a glycolipid biosurfactant, and then the treated acetone is obtained by separation, which is recorded as acetone 1;

[0012] (2) The acetone 1 and formaldehyde are introduced into a pipeline reactor and reacted under supercritical conditions to obtain the butanone alcohol.

[0013] In step (1), the treatment time is 1 to 6 hours, preferably 2 to 4 hours.

[0014] In step (1), the treatment temperature is 20-40°C, preferably 30-40°C.

[0015] In step (1), the glycolipid biosurfactant is selected from one or more of rhamnolipids, trehalolipids, sophorolipids, and mannosyl erythritol esters.

[0016] The mass ratio of the glycolipid biosurfactant to the recovered acetone is 0.01-0.2:1, preferably 0.02-0.16:1, and more preferably 0.08-0.16:1.

[0017] The recycled acetone is recycled chemical acetone or natural acetone; the formaldehyde is chemical formaldehyde or natural formaldehyde. The natural acetone and natural formaldehyde are obtained by biological methods (fermentation, biological extraction), and can be used to prepare natural equivalent products.

[0018] In step (1), the separation method is atmospheric distillation, preferably to completely separate acetone.

[0019] In step (2), the molar ratio of the acetone 1 to the formaldehyde is 1.0-3.0:1, preferably 1.2-2.0:1, and more preferably 1.2-1.8:1.

[0020] In step (2), the feed rate of acetone 1 is 15-25 g / min.

[0021] In step (2), the temperature of the supercritical condition is 220-260°C, preferably 230-240°C.

[0022] In step (2), the pressure of the supercritical condition is 6-18 MPa, preferably 8-14 MPa, and more preferably 10-14 MPa.

[0023] In step (2), the residence time of the supercritical reaction is 1.0 to 6 min.

[0024] In step (2), after the reaction is completed, the recovered acetone is obtained by distillation, and the recovered acetone is returned to step (1) for use. Different batches of recovered acetone can be collected and used uniformly.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The present invention provides a method for preparing butanone alcohol by using a biosurfactant to optimize the treatment and recovery of acetone, and then using the treated raw material and formaldehyde to react under supercritical conditions. The inventors speculate that the acetone recovered after treatment in this method is activated, and exhibits better reaction activity in the next step of the reaction, inhibiting the occurrence of side reactions, achieving a high reaction yield, and significantly reducing the amount of acetone. This method not only solves the environmental and energy consumption problems caused by excessive acetone in the industrial production of butanone alcohol, but also avoids the high energy consumption and quality loss caused by the separation of acetone in the later stage.

[0027] (2) The present invention can also be used to recycle natural acetone and use it and natural formaldehyde as raw materials to synthesize natural butanone alcohol, which can be applied to the synthesis of downstream products, such as natural equivalent raspberry ketone, bio-based 1,3-butanediol, etc., which has great economic value. DETAILED DESCRIPTION

[0028] The present invention is further described in detail with reference to the following examples, but the scope of the present invention is not limited to these examples.

[0029] The conversion rate of the reaction in the embodiments and comparative examples was calculated by the following formula:

[0030]

[0031] The selectivity of the reaction in the embodiments and comparative examples is calculated by the following formula:

[0032]

[0033] Unless otherwise specified, the raw materials used in the following examples are commercially available. Example 1

[0034] In a 500ml three-necked flask equipped with a stirrer, a condenser and a thermometer, add recovered acetone (200g, 3.44mol) and then rhamnolipid (16g). Heat to 30°C and stir for 4 hours. Then, raise the temperature to 78°C and distill at normal pressure until no acetone is evaporated. A total of 1,199.8g of acetone is obtained.

[0035] The feed rate of acetone 1 was 20 g / min, and the feed rate of formaldehyde solution (mass fraction 37%) was 17.47 g / min (acetone: formaldehyde molar ratio = 1:1.6). They were preheated to 240 ° C and pressurized to 10.0 MPa before entering the tubular reactor. The materials stayed in the tubular reactor for 4 minutes. Using GC analysis, the formaldehyde conversion rate was 99.9%, the butanone alcohol selectivity was 99.8%, and no by-product ketone was detected. The reaction solution was separated by an evaporator to remove excess acetone (74.2 g) and collected for the next reaction. Example 2

[0036] In a 500ml three-necked flask equipped with a stirrer, a condenser and a thermometer, add recovered acetone (200g, 3.44mol) and then trehalose lipid (16g). Heat to 30°C, keep stirring for 4 hours, then raise the temperature to 78°C and distill at normal pressure until no acetone is evaporated. A total of 1,199.9g of acetone is obtained.

[0037] The feed rate of acetone 1 was 20 g / min, and the feed rate of formaldehyde solution (mass fraction 37%) was 17.47 g / min (acetone: formaldehyde molar ratio = 1:1.6). They were preheated to 240 ° C and pressurized to 10.0 MPa before entering the tubular reactor. The materials stayed in the tubular reactor for 4 minutes. Using GC analysis, the formaldehyde conversion rate was 99.9%, the butanone alcohol selectivity was 99.9%, and no by-product ketone was detected. The reaction solution was separated by an evaporator to separate excess acetone (74.1 g) and collected for the next reaction. Example 3

[0038] In a 500 ml three-necked flask equipped with a stirrer, a condenser and a thermometer, add recovered acetone (200 g, 3.44 mol) and then add sophorolipid (16 g). Heat to 30 °C. After stirring for 4 hours, raise the temperature to 78 °C and distill at atmospheric pressure until no acetone is evaporated. A total of 1,199.9 g of acetone is obtained.

[0039] The feed rate of acetone 1 was 20 g / min, and the feed rate of formaldehyde solution (mass fraction 37%) was 17.47 g / min (acetone: formaldehyde molar ratio = 1:1.6). They were preheated to 240 ° C and pressurized to 10.0 MPa before entering the tubular reactor. The materials stayed in the tubular reactor for 4 minutes. Using GC analysis, the formaldehyde conversion rate was 99.8%, the butanone alcohol selectivity was 99.6%, and no by-product ketone was detected. The reaction solution was separated by an evaporator to remove excess acetone (74.6 g) and collected for the next reaction. Example 4

[0040] In a 500ml three-necked flask equipped with a stirrer, a condenser and a thermometer, add recovered acetone (200g, 3.44mol), then add mannitol erythritol ester (16g), heat to 30℃, keep stirring for 4 hours, then raise the temperature to 78℃ and distill at normal pressure until no acetone is evaporated, to obtain 1,199.8g of acetone in total.

[0041] The feed rate of acetone 1 was 20 g / min, and the feed rate of formaldehyde solution (mass fraction 37%) was 17.47 g / min (acetone: formaldehyde molar ratio = 1:1.6). They were preheated to 240 ° C and pressurized to 10.0 MPa before entering the tubular reactor. The materials stayed in the tubular reactor for 4 minutes. Using GC analysis, the formaldehyde conversion rate was 99.8%, the butanone alcohol selectivity was 99.2%, and no by-product ketone was detected. The reaction solution was separated by an evaporator to remove excess acetone (74.1 g) and collected for the next reaction.

[0042] Embodiment 5-16

[0043] Rhamnolipid was used as the optimization agent, and only its usage, treatment time and treatment temperature were changed. Other operations and parameters were the same as those in Example 1. The specific reaction results are shown in the following table.

[0044] Table 1

[0045]

[0046] Examples 17-35

[0047] Rhamnolipid was used as the optimizing agent, and only the feed amount of formaldehyde solution, the pressure, temperature and residence time of the supercritical reaction were changed. Other operations and parameters were the same as those in Example 1. The specific reaction results are shown in the following table.

[0048] Table 2

[0049] Embodiment 36

[0050] In a 500ml three-necked flask equipped with a stirrer, a condenser and a thermometer, add rhamnolipid (16g) to the recovered natural acetone (200g, 3.44mol), heat to 30℃, keep stirring for 4 hours, then raise the temperature to 78℃ and distill at normal pressure until no more natural acetone is evaporated. A total of 1,199.8g of natural acetone is obtained.

[0051] The feed rate of natural acetone 1 was 20 g / min, and the feed rate of natural formaldehyde solution (mass fraction 37%) was 17.47 g / min (acetone: formaldehyde molar ratio = 1:1.6). They were preheated to 240 ° C and pressurized to 10.0 MPa before entering the tubular reactor. The materials stayed in the tubular reactor for 4 minutes. Using GC analysis, the natural formaldehyde conversion rate was 99.8%, the natural butanone alcohol selectivity was 99.2%, and no by-product ketone was detected. The reaction solution was separated by an evaporator to remove excess natural acetone (74.1 g) and collected for the next reaction.

[0052] Comparative Example 1

[0053] Acetone was recovered by treatment with PEG-based surfactants.

[0054] In a 500ml three-necked flask equipped with a stirrer, a condenser and a thermometer, add PEG200 (16g) to the recovered acetone (200g, 3.44mol), heat to 30℃, keep stirring for 4 hours, then raise the temperature to 78℃ and distill at atmospheric pressure until no acetone is evaporated. A total of 1,199.5g of acetone is obtained.

[0055] The feed rate of acetone 1 was 20 g / min, and the feed rate of formaldehyde solution was 17.47 g / min (acetone: formaldehyde molar ratio = 1:1.6). They were preheated to 240°C and pressurized to 10.0 MPa before entering the tubular reactor. The materials stayed in the tubular reactor for 4 minutes. GC analysis showed that the formaldehyde conversion rate was 92.8%, the butanone alcohol selectivity was 67.2%, and the ketene byproduct selectivity was 1.85%.

[0056] Comparative Example 2

[0057] The recovered acetone was not treated. The feed rate of the recovered acetone was 20 g / min, and the feed rate of the formaldehyde solution was 17.47 g / min (acetone: formaldehyde molar ratio = 1:1.6). They were preheated to 240 ° C and pressurized to 12.0 MPa, and then entered the tubular reactor. The materials stayed in the tubular reactor for 4 minutes. Using GC analysis, the formaldehyde conversion rate was 97.2%, the butanone alcohol selectivity was 61.3%, and the ketene byproduct selectivity was 3.86%.

Claims

1. A method for synthesizing butanone alcohol, characterized in that: The following steps are involved: (1) treating the recovered acetone with a glycolipid biosurfactant, and then obtaining treated acetone through separation; (2) passing the treated acetone and formaldehyde into a pipeline reactor to react under supercritical conditions to obtain the butanone alcohol; In step (1), the glycolipid biosurfactant is selected from one or more of rhamnolipids, trehalolipids, sophorolipids, and mannosyl erythritol esters; The mass ratio of the glycolipid biosurfactant to the recovered acetone is 0.01-0.2:1; In step (1), the treatment temperature is 20-40°C and the treatment time is 1-6 hours; In step (1), the separation is performed by atmospheric distillation until no acetone is evaporated.

2. The method for synthesizing butanone alcohol according to claim 1, characterized in that In step (1), the treatment temperature is 30-40°C and the treatment time is 2-4 hours.

3. The method for synthesizing butanone alcohol according to claim 1, characterized in that In step (1), the recovered acetone is recycled chemical acetone or natural acetone; the formaldehyde is chemical formaldehyde or natural formaldehyde.

4. The method for synthesizing butanone alcohol according to claim 1, characterized in that In step (2), the molar ratio of the acetone to the formaldehyde is 1.0-3.0:

1.

5. The method for synthesizing butanone alcohol according to claim 1, characterized in that In step (2), the temperature of the supercritical condition is 220-260° C., and the pressure of the supercritical condition is 6-18 MPa.

6. The method for synthesizing butanone alcohol according to claim 1, characterized in that: In step (2), the residence time of the reaction under supercritical conditions is 1.0 to 6.0 min.

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