CN114456040A - Method for separating dihydric alcohol through carbonyl transfer reaction - Google Patents
Method for separating dihydric alcohol through carbonyl transfer reaction Download PDFInfo
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- CN114456040A CN114456040A CN202210236680.1A CN202210236680A CN114456040A CN 114456040 A CN114456040 A CN 114456040A CN 202210236680 A CN202210236680 A CN 202210236680A CN 114456040 A CN114456040 A CN 114456040A
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
- C07C29/88—Separation; Purification; Use of additives, e.g. for stabilisation by treatment giving rise to a chemical modification of at least one compound
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
- C07C29/76—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
- C07C29/76—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment
- C07C29/80—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment by distillation
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
- C07C29/76—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment
- C07C29/86—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment by liquid-liquid treatment
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Abstract
The invention relates to a method for separating dihydric alcohol by carbonyl transfer reaction, which comprises the following steps: reaction (I): mixing the dihydric alcohol mixture with urea and a catalyst to perform a carbonyl transfer reaction; adjusting the pH value of the reaction system to 6-9, and stopping the reaction; (II) product separation: the unreacted diol is separated from the reaction product. According to the method, certain dihydric alcohol can be fully converted through a carbonyl transfer reaction, the conversion rate of other dihydric alcohol is very low, and the dihydric alcohol with higher purity can be obtained after the product is separated. Compared with the prior art, the invention has the advantages that: mild reaction conditions, energy conservation, low fixed investment and operation cost, less side reaction, higher separation efficiency and the like.
Description
Technical Field
The invention relates to a method for separating dihydric alcohol through a carbonyl transfer reaction, belonging to the technical field of chemical separation.
Background
The dihydric alcohol is an important organic synthetic industrial raw material and has wide application in the aspects of chemical fiber, plastics, food, daily chemical industry, medicine synthesis and the like. For example, ethylene glycol is used to synthesize polyester, which in turn is used to produce packaging materials, textile fibers, films, and the like, and thus the industry demand for ethylene glycol is great. With the increasing exhaustion of petroleum resources and the increasing severity of global warming problems, the technology of synthesizing dihydric alcohol by using coal and biomass as raw materials will gradually replace petroleum routes. However, since the selectivity of the relevant reaction is not high, the product is a mixture of various diols, and the purity of the product cannot meet the requirements of downstream production. In addition, the boiling point of the dihydric alcohol is high and close, oligomerization is easy to occur at high temperature, if the dihydric alcohol mixture is separated by rectification, the energy consumption is high, and the purity of the product is difficult to reach a high level. The melting point of the glycol is low and the operating conditions will be very severe if isolated by crystallization. The polarity of the diols is close, and if separation is performed by extraction, the separation efficiency is generally not high. Therefore, there is an urgent need to develop a technology for separating a glycol mixture with high efficiency, low cost and low energy consumption.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: provided is a method for separating diols by a carbonyl transfer reaction, which can sufficiently convert some diols and have a low conversion rate of other diols by the carbonyl transfer reaction, and can obtain diols with higher purity after separating the product.
The technical scheme for solving the technical problems is as follows: a method for separating glycols by a carbonyl transfer reaction comprising the steps of:
reaction (I): mixing the dihydric alcohol mixture with urea and a catalyst to perform a carbonyl transfer reaction; adjusting the pH value of the reaction system to 6-9, and stopping the reaction;
(II) product separation: the unreacted diol is separated from the reaction product.
In the step (one), the mass ratio of urea to dihydric alcohol is 0.02-5; the catalyst comprises one or more of sodium hydroxide, potassium hydroxide, lithium carbonate, sodium carbonate, potassium carbonate and cesium carbonate, and the mass ratio of the catalyst to the dihydric alcohol is 0.002-0.2; the reaction temperature is 60-160 ℃, and the reaction time is 1-12 hours;
the method adopted in the separation in the step (II) is as follows: one or more of distillation, extraction, melt crystallization and centrifugal separation.
In the step (I), the pressure of the reaction system is controlled to be 30 kPa-80 kPa.
Further, in the step (one), the reaction temperature is 90-140 ℃, and the reaction time is 2-6 hours.
The mass ratio of the urea to the impurity dihydric alcohol is 1-10.
The mass ratio of the catalyst to the impurity dihydric alcohol is 0.05-2.
In the step (II), the separation method comprises the steps of placing the mixture after the reaction is stopped in an environment with the temperature of minus 15-minus 5 ℃ for freezing for 0.1-1 hour to separate out solid carbonate, filtering or centrifuging to remove the solid carbonate under the condition with the temperature of minus 15-minus 5 ℃, and taking out liquid to obtain the dihydric alcohol product with improved purity.
In the step (II), the separation method is to mix the mixture after the reaction is ended with an extracting agent, extract and separate esters, and take out raffinate phase to obtain the dihydric alcohol product with improved purity.
The extracting agent is alkane, arene, ester or ketone, and the mass ratio of the extracting agent to the dihydric alcohol is 0.05-1.
The dihydric alcohol mixture in the step (I) contains two or more of ethylene glycol, propylene glycol, butanediol, pentanediol and hexanediol.
The principle of the invention for separating the dihydric alcohol mixture is as follows: the dihydric alcohol with high carbon number has stronger carbonyl transfer reaction activity, the dihydric alcohol with high carbon number reacts with urea under the action of an alkaline catalyst to be fully converted into carbonic ester, the dihydric alcohol with low carbon number has very low conversion rate or is not converted basically, the ester product has lower boiling point or lower polarity or higher melting point, and is easy to be separated from the mixture by the technologies of distillation, extraction, melting crystallization and the like, and the dihydric alcohol product with high carbon number is finally obtained.
Compared with the prior art, the invention has the advantages that: the reaction condition is mild, the energy is saved, the fixed investment and the operation cost are low, the side reaction is less, and the separation efficiency is higher; can produce high value-added products such as ethylene carbonate, propylene carbonate, butylene carbonate and the like as byproducts.
The technical features of one of the methods for separating a diol by a transesterification reaction according to the present invention will be further described with reference to examples.
Detailed Description
The required equipment includes: a reaction kettle, a heater, a stirring device, a separating device and the like.
Example one
Under normal pressure, 8 g of ethylene glycol and 2 g of 1, 2-propylene glycol are put into a reaction kettle, 3 g of urea is added, the liquid phase temperature is controlled to be 120 ℃, and the mixture is stirred at the rotating speed of 300 rpm; 0.2 g of sodium hydroxide was added and reacted for 5 hours. 10% sulfuric acid was added to adjust the pH of the mixture to 7, and the reaction was terminated. And removing the mixture, freezing the mixture in an environment at the temperature of minus 10 ℃ for half an hour to separate out the carbonic ester, centrifuging the mixture at the temperature of minus 10 ℃ for 10 minutes at the rotating speed of 5000rpm, taking out the liquid, weighing the liquid, and analyzing the liquid by gas chromatography to obtain a product containing 90.2% of glycol by mass and 89.5% of glycol yield.
Example two
Putting 8 g of ethylene glycol and 2 g of 1, 2-butanediol into a reaction kettle, adding 3 g of urea, controlling the liquid phase temperature to be 110 ℃, controlling the pressure of a reaction system to be 40kPa (ammonia gas can be discharged under reduced pressure, the reaction effect is better), and stirring the mixture at the rotating speed of 300 rpm; 0.2 g of cesium carbonate was added and reacted for 5 hours. 10% sulfuric acid was added to adjust the pH of the mixture to 7, and the reaction was terminated. And removing the mixture, mixing with 5 ml of n-hexane, stirring for 10 minutes, extracting and separating esters, taking out a raffinate phase, weighing, and analyzing by using gas chromatography to obtain a product containing 93.3% of glycol by mass and 90% of glycol yield.
EXAMPLE III
Under normal pressure, 9 g of 1, 2-propylene glycol and 1 g of 1, 2-pentanediol are put into a reaction kettle, 5 g of urea is added, the temperature of a liquid phase is controlled to be 120 ℃, and the mixture is stirred at the rotating speed of 300 rpm; 0.2 g of potassium hydroxide was added and reacted for 12 hours. 10% sulfuric acid was added to adjust the pH of the mixture to 7, and the reaction was terminated. And removing the mixture, freezing the mixture in an environment at the temperature of minus 10 ℃ for half an hour to separate out the carbonic ester, centrifuging the mixture at the temperature of minus 10 ℃ for 10 minutes at the rotating speed of 5000rpm, taking out the liquid, weighing the liquid, and analyzing the liquid by gas chromatography to obtain the product containing 95.1 percent of 1, 2-propylene glycol by mass and 89.8 percent of 1, 2-propylene glycol by yield.
Example four
Under normal pressure, 8 g of 1, 2-butanediol and 2 g of 1, 2-hexanediol are put into a reaction kettle, 3 g of urea is added, the reaction is carried out at 100 ℃, and the mixture is stirred at the rotating speed of 300 rpm; 0.2 g of potassium carbonate was added thereto, and the reaction was carried out for 1 hour. 10% sulfuric acid was added to adjust the pH of the mixture to 7, and the reaction was terminated. And removing the mixture, mixing the mixture with 6 ml of cyclohexane, stirring the mixture for 10 minutes, extracting and separating esters, taking out a raffinate phase, weighing the raffinate phase, and analyzing the raffinate phase by using gas chromatography to obtain a product containing 84.3% of 1, 2-butanediol by mass concentration and 96.1% of 1, 2-butanediol by yield.
EXAMPLE five
Putting 9 g of ethylene glycol and 1 g of 2, 3-butanediol into a reaction kettle, adding 3.5 g of urea, controlling the liquid phase temperature to be 60 ℃ and the pressure of a reaction system to be 50kPa (ammonia gas can be discharged under reduced pressure, the reaction effect is better), and stirring the mixture at the rotating speed of 400 rpm; 0.2 g of potassium hydroxide was added and reacted for 6 hours. 5% sulfuric acid was added to adjust the pH of the mixture to 7, and the reaction was terminated. And removing the mixture, freezing the mixture at the temperature of minus 10 ℃ for 1 hour to separate out the carbonic ester, centrifuging the mixture at the temperature of minus 10 ℃ at the rotating speed of 6000rpm for 5 minutes, taking out the liquid, weighing the liquid, and analyzing the liquid by gas chromatography to obtain the product with the mass concentration of the glycol of 94.8 percent and the yield of the glycol of 90.2 percent.
EXAMPLE six
Under normal pressure, 8 g of 1, 2-propylene glycol and 2 g of 1, 2-hexanediol are put into a reaction kettle, 3 g of urea is added, the temperature of a liquid phase is controlled to be 160 ℃, and the mixture is stirred at the rotating speed of 300 rpm; 0.3 g of sodium carbonate was added and reacted for 3 hours. The reaction was terminated by adding 3% sulfuric acid and adjusting the pH of the mixture to 7. And removing the mixture, mixing with 6 ml of n-octane, stirring for 5 minutes, extracting and separating esters, taking out a raffinate phase, weighing, and analyzing by using gas chromatography to obtain a product containing 88.9% of 1, 2-propylene glycol by mass and 93.3% of 1, 2-propylene glycol by yield.
EXAMPLE seven
Putting 8 g of 1, 2-propylene glycol and 2 g of 1, 2-butanediol into a reaction kettle, adding 6 g of urea, controlling the liquid phase temperature to be 90 ℃ and the pressure of a reaction system to be 50kPa (ammonia gas can be discharged under reduced pressure, the reaction effect is better), and stirring the mixture at the rotating speed of 300 rpm; 0.2 g of lithium carbonate was added and reacted for 6 hours. The reaction was terminated by adding 3% sulfuric acid and adjusting the pH of the mixture to 7. And removing the mixture, mixing with 4 ml of n-octane, stirring for 5 minutes, extracting and separating esters, taking out a raffinate phase, weighing, and analyzing by using gas chromatography to obtain a product containing 91.2% of 1, 2-propylene glycol by mass and 93.7% of 1, 2-propylene glycol by yield.
Example eight
Under normal pressure, 7 g of ethylene glycol, 1 g of 1, 2-butanediol, 1 g of 1, 2-pentanediol and 1 g of 1, 2-hexanediol are put into a reaction kettle, 5 g of urea is added, the liquid phase temperature is controlled at 120 ℃, and the mixture is stirred at the rotating speed of 300 rpm; 0.2 g of sodium hydroxide was added and reacted for 5 hours. 10% sulfuric acid was added to adjust the pH of the mixture to 7, and the reaction was terminated. And removing the mixture, separating the dihydric alcohol by distillation, collecting distillate with the normal pressure boiling range of 187-200 ℃, weighing, and analyzing by gas chromatography to obtain the product with the mass concentration of the glycol of 84.9 percent and the yield of the glycol of 81.1 percent.
Example nine
Putting 6 g of ethylene glycol, 1 g of 1, 2-propylene glycol, 1 g of 1, 2-butanediol, 1 g of 1, 2-pentanediol and 1 g of 1, 2-hexanediol into a reaction kettle, adding 5 g of urea, controlling the liquid phase temperature to be 115 ℃ and the pressure of a reaction system to be 40kPa (ammonia gas can be discharged under a reduced pressure condition, the reaction effect is better), and stirring the mixture at the rotating speed of 300 rpm; 0.3 g of cesium carbonate was added and reacted for 5 hours. 10% sulfuric acid was added to adjust the pH of the mixture to 7, and the reaction was terminated. And (3) removing the mixture, separating the dihydric alcohol by distillation by using a rectifying column, collecting distillate with the normal pressure boiling range of 187-200 ℃, weighing, and analyzing by using gas chromatography to obtain the product with the mass concentration of the glycol of 91.3 percent and the yield of the glycol of 86.4 percent.
Claims (10)
1. A method for separating glycols by a carbonyl transfer reaction, characterized in that: the method comprises the following steps:
reaction (I): mixing the dihydric alcohol mixture with urea and a catalyst to perform a carbonyl transfer reaction; adjusting the pH value of the reaction system to 6-9, and stopping the reaction;
(II) product separation: the unreacted diol is separated from the reaction product.
2. A method of separating glycols by a carbonyl transfer reaction as claimed in claim 1, characterized in that:
in the step (one), the mass ratio of urea to dihydric alcohol is 0.02-5; the catalyst comprises one or more of sodium hydroxide, potassium hydroxide, lithium carbonate, sodium carbonate, potassium carbonate and cesium carbonate, and the mass ratio of the catalyst to the dihydric alcohol is 0.002-0.2; the reaction temperature is 60-160 ℃, and the reaction time is 1-12 hours;
the method adopted in the separation in the step (II) is as follows: one or more of distillation, extraction, melt crystallization and centrifugal separation.
3. A method of separating glycols by a carbonyl transfer reaction as claimed in claim 2, characterized in that: in the step (I), the pressure of the reaction system is controlled to be 30 kPa-80 kPa.
4. A method of separating glycols by a carbonyl transfer reaction as claimed in claim 2, characterized in that: in the step (one), the reaction temperature is 90-140 ℃ and the reaction time is 2-6 hours.
5. A method of separating glycols by a carbonyl transfer reaction as claimed in claim 2, characterized in that: the mass ratio of the urea to the impurity dihydric alcohol is 1-10.
6. A method of separating glycols by a carbonyl transfer reaction as claimed in claim 2, characterized in that: the mass ratio of the catalyst to the impurity dihydric alcohol is 0.05-2.
7. A method of separating glycols by a carbonyl transfer reaction as claimed in claim 2, characterized in that: in the step (II), the separation method comprises the steps of placing the mixture after the reaction is stopped in an environment with the temperature of minus 15-minus 5 ℃ for freezing for 0.1-1 hour to separate out solid carbonate, filtering or centrifuging to remove the solid carbonate under the condition with the temperature of minus 15-minus 5 ℃, and taking out liquid to obtain the dihydric alcohol product with improved purity.
8. A method of separating glycols by a carbonyl transfer reaction as claimed in claim 2, characterized in that: in the step (II), the separation method is to mix the mixture after the reaction is ended with an extracting agent, extract and separate esters, and take out raffinate phase to obtain the dihydric alcohol product with improved purity.
9. The process of claim 8, wherein the glycol is isolated by a carbonyl transfer reaction, wherein: the extracting agent is alkane, arene, ester or ketone, and the mass ratio of the extracting agent to the dihydric alcohol is 0.05-1.
10. A method for separating glycols by a carbonyl transfer reaction according to any of claims 1-9, characterized in that: the dihydric alcohol mixture in the step (I) contains two or more of ethylene glycol, propylene glycol, butanediol, pentanediol and hexanediol.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210236680.1A CN114456040A (en) | 2022-03-11 | 2022-03-11 | Method for separating dihydric alcohol through carbonyl transfer reaction |
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| CN202210236680.1A CN114456040A (en) | 2022-03-11 | 2022-03-11 | Method for separating dihydric alcohol through carbonyl transfer reaction |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1421431A (en) * | 2002-12-16 | 2003-06-04 | 中国科学院山西煤炭化学研究所 | Synthesis process of propylene carbonate or vinyl carbonate |
| US20170327446A1 (en) * | 2014-11-28 | 2017-11-16 | Dalian Institute Of Chemical Physics, Chinese Academy Of Sciences | Method for Separation of Close-Boiling Mixture of Polyols |
| CN108794300A (en) * | 2018-05-18 | 2018-11-13 | 岳阳昌德化工实业有限公司 | The Isolation method of raw material containing ethylene glycol and 1,2- butanediols and the preparation method of epoxy butane |
-
2022
- 2022-03-11 CN CN202210236680.1A patent/CN114456040A/en not_active Withdrawn
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1421431A (en) * | 2002-12-16 | 2003-06-04 | 中国科学院山西煤炭化学研究所 | Synthesis process of propylene carbonate or vinyl carbonate |
| US20170327446A1 (en) * | 2014-11-28 | 2017-11-16 | Dalian Institute Of Chemical Physics, Chinese Academy Of Sciences | Method for Separation of Close-Boiling Mixture of Polyols |
| CN108794300A (en) * | 2018-05-18 | 2018-11-13 | 岳阳昌德化工实业有限公司 | The Isolation method of raw material containing ethylene glycol and 1,2- butanediols and the preparation method of epoxy butane |
Non-Patent Citations (2)
| Title |
|---|
| LI, HONG，等: "Application of the Aldolization Reaction in Separating the Mixture of Ethylene Glycol and 1,2-Butanediol: Thermodynamics and New Separation Process", 《INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH》, vol. 55, no. 37, pages 9994 - 10003 * |
| SHUO AI，等: "Selective Removal of 1,2-Propanediol and 1,2-Butanediol from Bio-Ethylene Glycol by Catalytic Reaction", 《AICHE JOURNAL》, vol. 63, no. 09, pages 4032 * |
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