CN114956980B - Method for synthesizing crotonic acid - Google Patents

Method for synthesizing crotonic acid Download PDF

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CN114956980B
CN114956980B CN202210552431.3A CN202210552431A CN114956980B CN 114956980 B CN114956980 B CN 114956980B CN 202210552431 A CN202210552431 A CN 202210552431A CN 114956980 B CN114956980 B CN 114956980B
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reaction
liquid
crotonaldehyde
crotonic acid
gas
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CN114956980A (en
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周益峰
杨汝静
黄晋培
李勇翔
彭强
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Hangzhou Ledun Micro Technology Co ltd
China Jiliang University
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Hangzhou Ledun Micro Technology Co ltd
China Jiliang University
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/16—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation
    • C07C51/21—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen
    • C07C51/23—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of oxygen-containing groups to carboxyl groups
    • C07C51/235—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of oxygen-containing groups to carboxyl groups of —CHO groups or primary alcohol groups
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/0093—Microreactors, e.g. miniaturised or microfabricated reactors
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/42—Separation; Purification; Stabilisation; Use of additives
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/42—Separation; Purification; Stabilisation; Use of additives
    • C07C51/43—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/42—Separation; Purification; Stabilisation; Use of additives
    • C07C51/43—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation
    • C07C51/44—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation by distillation
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/42—Separation; Purification; Stabilisation; Use of additives
    • C07C51/47—Separation; Purification; Stabilisation; Use of additives by solid-liquid treatment; by chemisorption
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/584—Recycling of catalysts

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

The invention discloses a method for synthesizing crotonic acid, which comprises the following steps: the crotonaldehyde and oxygen-containing gas are subjected to a first-stage high-temperature high-pressure reaction in a micro-reactor, and the obtained reaction liquid is subjected to gas-liquid separation and then enters a tubular reactor to realize the process of converting the peracid intermediate into crotonic acid at a lower temperature, namely a second-stage reaction. The synthesis and resolution of the crotonic acid are divided into two reaction stages, and the mixing and reaction of gas-liquid two phases in the gas oxidation process are enhanced through the characteristics of the microreactor, so that the reaction efficiency and the safety are improved; and secondly, through tubular reaction, the reaction temperature is reduced, the residence time is prolonged, and the conversion selectivity of the peracid serving as a reaction intermediate is improved, so that the generation of byproducts is obviously reduced. The continuous crotonic acid synthesis process effectively solves the problems of difficult control of reaction temperature, low production efficiency, unstable products and the like in the existing kettle type process, has the advantages of short production period, high selectivity and intrinsic safety, and is suitable for industrial production.

Description

Method for synthesizing crotonic acid
Technical Field
The invention belongs to the technical field of synthesis of fine chemical raw materials, and particularly relates to a method for synthesizing crotonic acid.
Background
Crotonic acid (CAS number: 107-93-7) is an unsaturated fatty acid and has wide industrial application, and is mainly used for synthesizing various resins, surface coatings and the like, and is also an important medical intermediate and pesticide intermediate.
The methods for preparing crotonic acid reported in the current literature mainly comprise oxygen oxidation, metal oxide oxidation and peroxide oxidation. The oxygen is used as an environment-friendly oxidant, and has the advantages of low cost, simple post-treatment, easy separation and the like. Zhang Yong et al (progress of fine petrochemical industry, 2007, volume No. 22-24) use aluminum oxide as a catalyst, introduce oxygen and oxidize crotonaldehyde by electrochemical methods, which, although yield reaches 80%, are expensive and inefficient in equipment and difficult to industrialize. Cheng Shaoguo et al (CN 1415594A) used noble metal silver as the catalyst and used air to oxidize crotonaldehyde in an oxidation tower with 75% yield, but the process has the disadvantages of high catalyst cost, complicated operation steps and long reaction period. Lin Jing et al (Xiamen university journal: nature science edition; 1993, volume No. 745-748) tested the effect of preparing crotonic acid by oxidizing crotonaldehyde with oxygen or air using active manganese dioxide, copper acetate-cobalt acetate and cobalt Schiff base complex as catalysts, respectively, and showed that active manganese dioxide and copper acetate-acetic acid aggravate polymerization side reaction of raw material crotonaldehyde, severely lowering reaction selectivity.
The mechanism of oxidizing crotonaldehyde by oxygen to crotonic acid is that crotonaldehyde combines with one molecule of oxygen to form a peroxy crotonic acid intermediate, and then the peroxy crotonic acid intermediate reacts with one molecule of crotonaldehyde to generate two molecules of crotonic acid.
The existing production process for preparing the crotonic acid by gas oxidation is mainly in a kettle type, and kettle type reaction equipment has the defects of high actual operation difficulty, low safety coefficient, poor process controllability and low reaction selectivity when in a crotonaldehyde oxidation process. The micro-reactor has outstanding advantages in the aspects of gas-liquid reaction mass transfer and heat transfer, and the development of the crotonaldehyde oxidation micro-reaction process can well solve a plurality of problems existing in a kettle type process, thereby realizing process reinforcement. Based on the full knowledge of the crotonic acid oxidation mechanism, the invention provides a novel micro-chemical continuous oxidation process, the mixing of gas and liquid phases is enhanced through the characteristics of micro-reaction equipment, and the reaction efficiency and the safety are improved; the reaction selectivity is improved through the two-stage reaction; no catalyst is used in the reaction process, and the method is green and environment-friendly.
Disclosure of Invention
The invention aims to provide a method for continuously preparing crotonic acid, which can effectively improve the production efficiency and the reaction selectivity, reduce the pressure of three-waste treatment, ensure the process controllability and the safety and realize the process reinforcement.
The technical scheme of the invention is as follows:
a process for continuously preparing crotonic acid comprising the steps of:
(1) And continuously introducing the crotonaldehyde-containing material A and the oxygen-containing material B into a microreactor to perform a first-stage reaction to obtain a reaction liquid C.
(2) The reaction liquid C from the microreactor enters a gas-liquid separation unit after pressure relief, nitrogen is continuously blown into the unit to remove residual oxygen in the liquid, and the obtained liquid D is directly led into the tubular reactor to carry out second-stage reaction, so that reaction liquid E is obtained.
(3) The reaction solution E flowing out of the tubular reactor enters an evaporator, unreacted raw materials and solvent are separated from products through the evaporator, and then the raw materials and the solvent are recycled after being rectified, so that crude feed liquid F is obtained at the bottom of the evaporator.
(4) And (3) refining the crude product feed liquid F obtained in the step (3) through post-treatment to obtain the product crotonic acid.
The material A in the step (1) is pure crotonaldehyde or an organic solution containing crotonaldehyde, and the organic solvent in the organic solution is hydrocarbon solvent, preferably C 5 ～C 10 Alkane solvent, C 5 ～C 10 Cycloalkane solvent, C 6 ～C 10 An aromatic hydrocarbon solvent; further, an inert solvent such as toluene, cyclohexane, n-hexane, and n-heptane is preferable, and toluene is most preferable.
Preferably, the volume and the usage ratio of the crotonaldehyde to the organic solvent is 1:1 to 4.
And (3) the material B in the step (1) is pure oxygen or mixed gas of nitrogen and oxygen.
The molar ratio of crotonaldehyde contained in the material A and oxygen contained in the material B in the microreactor fed into the step (1) is 1: (0.3-2.0).
The diameter of the microreactor channel in the step (1) is 0.5-4.0 mm, preferably 0.5-2.0 mm, and more preferably 1.5-2.0 mm; the reaction temperature is 50 to 100 ℃, more preferably 50 to 70 ℃; the residence time is 30-180 s, and the reaction pressure is 1-3 MPa.
The reaction temperature of the tubular reactor in the step (2) is 20-50 ℃, and the residence time of the reaction solution D in the reactor is 10-60 min.
The evaporator in the step (3) is a thin film evaporator or a rectifying tower.
The post-treatment procedure of the step (4) comprises active carbon decolorization and recrystallization, and the post-treatment can be carried out according to the prior art.
Compared with the prior art, the invention has the following advantages and outstanding technical effects:
according to the invention, by introducing the microreactor, the gas-liquid two-phase efficient mixing and reaction of crotonaldehyde and oxygen are realized, and the problem of low gas-liquid reaction efficiency in the traditional kettle reaction process is solved. The continuous process divides the reaction into two stages of high temperature, high pressure and low temperature and normal pressure, so that the two reaction stages of peracid formation and conversion in the crotonaldehyde oxidation process are basically separated, the gas oxidation efficiency is ensured, and the peracid conversion selectivity is improved. In addition, a gas-liquid separation unit is added between the two reaction stages, so that the pressure of the gas existing to the volume of the second-stage reactor is effectively relieved, the equipment cost is reduced, and the process safety is improved. The whole process takes oxygen as an oxidant, has high atomic utilization rate, is environment-friendly, and the first-stage reaction of the participation of the oxygen is carried out in the microreactor, so that the method is safe and controllable. As the reaction selectivity can be reduced along with the rising of the conversion rate of the crotonaldehyde, the proper conversion rate of the crotonaldehyde can be effectively ensured and the stability of the process can be improved by precisely controlling the reaction time and the reaction temperature of each stage.
Drawings
FIG. 1 is a flow chart of the process for synthesizing crotonic acid according to the invention.
Detailed Description
The invention provides a method for continuously preparing crotonic acid, and fig. 1 is a process flow chart of the invention, which specifically comprises the following steps:
continuously introducing a material A containing crotonaldehyde and a material B containing oxygen into a micro-reactor for a first-stage reaction, introducing the obtained reaction liquid C into a gas-liquid separation unit after pressure relief, continuously blowing nitrogen into the unit to remove residual oxygen in the liquid, directly introducing the obtained liquid D into the reactor for a second-stage reaction, introducing the obtained reaction liquid E into an evaporator, separating unreacted raw materials and solvent from products through the evaporator, subsequently recycling through a rectification unit, obtaining crude material liquid F at the bottom of the evaporator, and obtaining the product crotonic acid through post-treatment refining.
The invention is further illustrated below with reference to examples.
Example 1
Weighing 300g of crotonaldehyde, dissolving in n-hexane and fixing the volume to 800mL to obtain a material A; the oxygen coming out of the oxygen cylinder is not treated as material B. The materials A and B are respectively conveyed into a micro-channel reactor (Shenshi model TMC-01, internal size 1.6mm, material 316L, total channel volume 20 mL) by using a high-pressure flow pump and a gas mass flow controller, the reactor temperature is 70 ℃, the pressure is 2MPa, the flow rate of the material A is 5mL/min, and the flow rate of the material B is 0.2-0.4 SLM (standard liter per minute). The pressure is released by a pressure release valve, the liquid obtained after gas-liquid separation is introduced into a 316L reaction coil (the outer diameter is 3mm, the inner diameter is 2mm, the total length is 50m, and the normal pressure) at a flow rate of 5mL/min, and the water bath temperature outside the coil is 40 ℃. The reaction liquid flowing out of the coil pipe is distilled under reduced pressure to separate the raw materials and the solvent into the reaction liquid, 140g of crotonaldehyde is contained in the separation liquid through gas chromatography analysis external standard calculation, and the reaction conversion rate is 53%. The residual crude product feed liquid is decolorized and recrystallized by active carbon to obtain 160g of pure crotonic acid product with GC purity of more than 99%, and the yield is 81.4% calculated by consumed crotonaldehyde.
Example 2
Weighing 300g of crotonaldehyde, dissolving in n-hexane and fixing the volume to 800mL to obtain a material A; the air coming out of the air cylinder is not treated as material B. And conveying the materials A and B into a micro-channel reactor (Shenshi model TMC-02, internal size of 2mm, material of 316L and total channel volume of 90 mL) by using a high-pressure flow pump and a gas mass flow controller, wherein the reactor temperature is 70 ℃, the pressure is 2.5MPa, the flow rate of the material A is 5mL/min, and the flow rate of the material B is 1.3-1.5 SLM. The pressure is released by a pressure release valve, the liquid obtained after gas-liquid separation is introduced into a 316L reaction coil (the outer diameter is 3mm, the inner diameter is 2mm, the total length is 50m, and the normal pressure) at a flow rate of 5mL/min, and the water bath temperature outside the coil is 40 ℃. The reaction liquid flowing out of the coil pipe is distilled under reduced pressure to separate the raw materials and the solvent into the reaction liquid, and the separation liquid is calculated to contain 150g of crotonaldehyde by gas chromatography analysis external standard, so that the reaction conversion rate is 50%. The rest crude product feed liquid is decolorized and recrystallized by active carbon to obtain 155g of pure crotonic acid product, the GC purity is more than 99%, and the yield is 84.1% calculated by consumed crotonaldehyde.
Example 3
300g of crotonaldehyde is weighed, and no solvent is added as a material A; the air coming out of the air cylinder is not treated as material B. And conveying the materials A and B into a micro-channel reactor (Shenshi model TMC-02, internal size of 2mm, material of 316L and total channel volume of 90 mL) by using a high-pressure flow pump and a gas mass flow controller respectively, wherein the reactor temperature is 70 ℃, the pressure is 2MPa, the flow rate of the material A is 5mL/min, and the flow rate of the material B is 1.3-1.5 SLM. The pressure is released by a pressure release valve, the liquid obtained after gas-liquid separation is introduced into a 316L reaction coil (the outer diameter is 3mm, the inner diameter is 2mm, the total length is 50m, and the normal pressure) at a flow rate of 5mL/min, and the water bath temperature outside the coil is 40 ℃. The reaction liquid flowing out of the coil pipe is distilled under reduced pressure to separate the raw materials and the solvent into the reaction liquid, 130g of crotonaldehyde is contained in the separation liquid through gas chromatography analysis external standard calculation, and the reaction conversion rate is 57%. The residual crude product feed liquid is decolorized and recrystallized by active carbon to obtain the pure crotonic acid product 158g, the GC purity is more than 99 percent, and the yield is 75.7 percent calculated by consumed crotonaldehyde.
Example 4
300g of crotonaldehyde is weighed, dissolved in toluene and fixed to 800mL to obtain a material A; the air coming out of the air cylinder is not treated as material B. And conveying the materials A and B into a micro-channel reactor (Shenshi TMC-02, internal dimension is 2mm, material 316L and total channel volume is 90 mL) by using a high-pressure flow pump and a gas mass flow controller, wherein the reactor temperature is 70 ℃, the pressure is 2MPa, the flow rate of the material A is 5mL/min, and the flow rate of the material B is 1.3-1.5 SLM. The pressure is released by a pressure release valve, the liquid obtained after gas-liquid separation is introduced into a 316L reaction coil (the outer diameter is 3mm, the inner diameter is 2mm, the total length is 50m, and the normal pressure) at a flow rate of 5mL/min, and the water bath temperature outside the coil is 40 ℃. The reaction liquid flowing out of the coil pipe is distilled under reduced pressure to separate the raw materials and the solvent into the reaction liquid, 145g of crotonaldehyde is contained in the separation liquid through gas chromatography analysis external standard calculation, and the reaction conversion rate is 52%. The rest crude product feed liquid is decolorized and recrystallized by active carbon to obtain 173g of pure crotonic acid with GC purity of more than 99 percent, and the yield is 90.1 percent calculated by consumed crotonaldehyde.
Example 5
300g of crotonaldehyde is weighed, dissolved in toluene and fixed to 800mL to obtain a material A; the air coming out of the air cylinder is not treated as material B. And conveying the materials A and B into a micro-channel reactor (Shenshi TMC-02, internal dimension is 2mm, material 316L and total channel volume is 90 mL) by using a high-pressure flow pump and a gas mass flow controller, wherein the reactor temperature is 60 ℃, the pressure is 2MPa, the flow rate of the material A is 5mL/min, and the flow rate of the material B is 1.3-1.5 SLM. The pressure is released by a pressure release valve, the liquid obtained after gas-liquid separation is introduced into a 316L reaction coil (the outer diameter is 3mm, the inner diameter is 2mm, the total length is 50m, and the normal pressure) at a flow rate of 5mL/min, and the water bath temperature outside the coil is 30 ℃. The reaction liquid flowing out of the coil pipe is distilled under reduced pressure to separate the raw materials and the solvent into the reaction liquid, and the external standard is analyzed by gas chromatography to calculate that the separation liquid contains 210g of crotonaldehyde, and the reaction conversion rate is 30%. The residual crude product feed liquid is decolorized and recrystallized by active carbon to obtain 106g of pure crotonic acid with GC purity of more than 99 percent, and the yield is 95.9 percent calculated by consumed crotonaldehyde.
Example 6
150g of crotonaldehyde recovered in the processes of examples 4 and 5 was weighed, dissolved in toluene and fixed to a volume of 400mL, as material A; the air coming out of the air cylinder is not treated as material B. And conveying the materials A and B into a micro-channel reactor (Shenshi TMC-02, internal dimension is 2mm, material 316L and total channel volume is 90 mL) by using a high-pressure flow pump and a gas mass flow controller, wherein the reactor temperature is 60 ℃, the pressure is 2MPa, the flow rate of the material A is 5mL/min, and the flow rate of the material B is 1.3-1.5 SLM. The pressure is released by a pressure release valve, the liquid obtained after gas-liquid separation is introduced into a 316L reaction coil (the outer diameter is 3mm, the inner diameter is 2mm, the total length is 50m, and the normal pressure) at a flow rate of 5mL/min, and the water bath temperature outside the coil is 30 ℃. The reaction liquid flowing out of the coil pipe is distilled under reduced pressure to separate the raw materials and the solvent into the reaction liquid, and the reaction conversion rate is 32% by calculating 102g of crotonaldehyde in the separation liquid through gas chromatography analysis external standard. The residual crude product feed liquid is decolorized and recrystallized by active carbon to obtain 55g of pure crotonic acid with GC purity of more than 99%, and the yield is 93.3% calculated by consumed crotonaldehyde.
Comparative example 1
Weighing 300g of crotonaldehyde, dissolving in n-hexane and fixing the volume to 800mL to obtain a material A; the oxygen coming out of the oxygen cylinder is not treated as material B. And conveying the materials A and B into a micro-channel reactor (Shenshi model TMC-01, internal size of 1.6mm, material of 316L and total volume of the channel of 90 mL) by using a high-pressure flow pump and a gas mass flow controller respectively, wherein the reactor temperature is 70 ℃, the pressure is 2MPa, the flow rate of the material A is 2mL/min, and the flow rate of the material B is 0.1-0.15 SLM. The pressure is released through a pressure release valve, the reaction liquid after gas-liquid separation is distilled under reduced pressure to separate raw materials and solvent out of the reaction liquid, and the reaction conversion rate is 60% after gas chromatography analysis external standard calculation of 120g of crotonaldehyde contained in the separation liquid. The rest crude product feed liquid is decolorized and recrystallized by active carbon to obtain 160g of pure crotonic acid product with GC purity of more than 99 percent, and the yield of consumed crotonaldehyde is 72.3 percent.
Comparative example 2
300g of crotonaldehyde was weighed, dissolved in n-hexane and added to a three-necked flask with a constant volume of 700mL, placed in a 40 ℃ water bath, magnetically stirred, and air was blown into the solution at a flow rate of 0.05SLM for 48 h. After the reaction is finished, the reaction liquid is separated from the raw materials and the solvent by reduced pressure distillation, 180g of crotonaldehyde is contained in the separation liquid is calculated by gas chromatography analysis external standard, and the reaction conversion rate is 40%. The rest crude product feed liquid is decolorized and recrystallized by active carbon to obtain 96g of pure crotonic acid with GC purity of more than 99 percent, and the yield of consumed crotonaldehyde is 65.1 percent.

Claims (5)

1. A method for synthesizing crotonic acid, comprising the steps of:
(1) Continuously introducing a crotonaldehyde-containing material A and an oxygen-containing material B into a microreactor to perform a first-stage reaction to obtain a reaction solution C;
the material A is an organic solution containing crotonaldehyde, and an organic solvent in the organic solution is a hydrocarbon solvent;
the diameter of the micro-reactor channel in the step (1) is 0.5-4.0 mm, and the reaction temperature is 50-100 ℃; the residence time is 30-180 s, and the reaction pressure is 1-3 MPa;
(2) The reaction liquid C from the microreactor enters a gas-liquid separation unit after pressure relief, nitrogen is continuously blown into the unit to remove residual oxygen in the liquid, and the obtained liquid D is directly led into the microreactor to carry out second-stage reaction to obtain reaction liquid E;
the reaction temperature of the tubular reactor in the step (2) is 20-50 ℃, and the residence time of the reaction solution D in the reactor is 10-60 min;
(3) The reaction solution E flowing out of the tubular reactor enters an evaporator, unreacted raw materials and solvent are separated from products through the evaporator, and then the raw materials and the solvent are recycled through a rectifying unit, so that crude product feed liquid F is obtained at the bottom of the evaporator;
(4) The crude product feed liquid F obtained in the step (3) is refined by post-treatment to obtain the product crotonic acid
The organic solvent is one or more of toluene, cyclohexane, n-hexane and n-heptane;
in the step (1), the material B is pure oxygen or mixed gas of nitrogen and oxygen.
2. The method according to claim 1, wherein the volume ratio of crotonaldehyde to organic solvent is 1: 1-4.
3. The process of claim 1, wherein the molar ratio of crotonaldehyde contained in feed a to oxygen contained in feed B in step (1) fed to the microreactor is 1: (0.3-2.0).
4. The method of claim 1, wherein the evaporator in step (3) is a thin film evaporator or a rectifying column.
5. The method of claim 1, wherein in step (4), the post-treatment process comprises activated carbon decolorization and recrystallization.
CN202210552431.3A 2022-05-20 2022-05-20 Method for synthesizing crotonic acid Active CN114956980B (en)

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Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB595170A (en) * 1945-02-02 1947-11-27 Shawinigan Chem Ltd Production of crotonic acid

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB595170A (en) * 1945-02-02 1947-11-27 Shawinigan Chem Ltd Production of crotonic acid

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