CN112028757B - Preparation method of 3-methyl-2-cyclopentene-1-ketone - Google Patents
Preparation method of 3-methyl-2-cyclopentene-1-ketone Download PDFInfo
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- CN112028757B CN112028757B CN202010932899.6A CN202010932899A CN112028757B CN 112028757 B CN112028757 B CN 112028757B CN 202010932899 A CN202010932899 A CN 202010932899A CN 112028757 B CN112028757 B CN 112028757B
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- C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
- C07C45/61—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by reactions not involving the formation of >C = O groups
- C07C45/67—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by reactions not involving the formation of >C = O groups by isomerisation; by change of size of the carbon skeleton
- C07C45/68—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by reactions not involving the formation of >C = O groups by isomerisation; by change of size of the carbon skeleton by increase in the number of carbon atoms
- C07C45/72—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by reactions not involving the formation of >C = O groups by isomerisation; by change of size of the carbon skeleton by increase in the number of carbon atoms by reaction of compounds containing >C = O groups with the same or other compounds containing >C = O groups
- C07C45/74—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by reactions not involving the formation of >C = O groups by isomerisation; by change of size of the carbon skeleton by increase in the number of carbon atoms by reaction of compounds containing >C = O groups with the same or other compounds containing >C = O groups combined with dehydration
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- B—PERFORMING OPERATIONS; TRANSPORTING
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- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/0093—Microreactors, e.g. miniaturised or microfabricated reactors
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- C07C2601/06—Systems containing only non-condensed rings with a five-membered ring
- C07C2601/10—Systems containing only non-condensed rings with a five-membered ring the ring being unsaturated
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Abstract
The invention provides a preparation method of 3-methyl-2-cyclopentene-1-ketone, which comprises a coil pipe type reactor and two plunger pumps, wherein the output ends of the plunger pumps are connected with the coil pipe type reactor, and the coil pipe type reactor is placed in an oil bath kettle at the temperature of 120-130 ℃; the preparation method comprises the following steps: s1, preparing a 2, 5-hexanedione aqueous solution and a 20% sodium hydroxide solution; s2, respectively immersing the plunger pump into a 2, 5-hexanedione aqueous solution and a 20% sodium hydroxide solution, and setting the flow rate to be 10-18 mL/min; s3, placing a 1L four-mouth bottle at the outlet of the reactor, cooling the heat conduction oil by external bath at 0-5 ℃, stopping reaction and sampling after receiving the reaction liquid for 30min, extracting with acetic acid, and performing GC analysis. The invention adopts a continuous reaction technology, and regulates and controls the selectivity of the reaction by adjusting the molar ratio, the feeding rate and the retention time of materials; and collecting and cooling the reaction liquid after the reaction is finished, so as to avoid the rapid decomposition of the product in hot alkali liquor. The reaction is carried out at a lower temperature by using water as a solvent, so that the pollution to the environment is reduced, and the energy consumption is reduced. The yield of the prepared 3-methyl-2-cyclopentene-1-ketone reaches 70-75%.
Description
Technical Field
The invention relates to a preparation method of 3-methyl-2-cyclopentene-1-ketone.
Background
3-methyl-2-cyclopenten-1-one is a yellowish to yellowish brown transparent liquid with a sweet caramel aroma. It can be used as perfume and pharmaceutical intermediate, and can be used for synthesizing various medicinal substances, including trichothecene toxin, adrenocortin, etc. The 3-methyl-2-cyclopentene-1-ketone is also a precursor of various substituted cyclopentadiene, and the substituted cyclopentadiene can react with various metals to generate a metallocene metal complex, which is an important catalyst for olefin polymerization. In addition, 3-methyl-2-cyclopentene-1-one can also be used as a gasoline additive to be applied to petrochemical industry, for example, methylcyclopentane which can be generated after hydrogenation of the gasoline additive has high octane number and energy density and can be used as a good ethanol gasoline substitute.
Robinson et al first obtained 3-methyl-2-cyclopenten-1-one by aldol condensation of 2, 5-hexanedione in hot sodium hydroxide solvent, but the yield of the product was only 40% with a conversion of 80%. Under the condition, the 2, 5-hexanedione can generate intermolecular dehydration polymerization to generate a large amount of tar, and the product is unstable under the high-temperature alkaline condition. (J.chem.Soc.,1952,1127-1133)
The improved experimental scheme of Houqilin et al adopts weak polar organic solvent, adds solid acid and alkali catalyst, and raises the reaction yield to above 80%. However, the reaction needs to be carried out in a large amount of organic solvent under the high-temperature condition of 140-250 ℃. (CN 105294418A)
Sato et al also used 2, 5-hexanedione as a raw material, subcritical or supercritical water as a medium, and obtained the product 3-methyl-2-cyclopenten-1-one in 91% yield without a catalyst. However, in order to achieve the subcritical and supercritical water state, the reaction needs to be carried out at the temperature of 300-400 ℃ and the pressure of 9-40 MPa, the conditions are very harsh, and the energy consumption and the safety risk are high. (JP 2005306820)
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provides a preparation method of 3-methyl-2-cyclopentene-1-ketone by adopting a continuous reaction technology.
In order to solve the technical problems, the invention adopts the technical scheme that: a preparation method of 3-methyl-2-cyclopentene-1-ketone comprises a coil pipe type reactor and two plunger pumps, wherein the output ends of the plunger pumps are connected with the coil pipe type reactor, and the coil pipe type reactor is placed in an oil bath pan at the temperature of 120-130 ℃; the preparation method comprises the following steps:
s1, preparing a 2, 5-hexanedione aqueous solution and a 20% sodium hydroxide solution;
s2, respectively immersing the plunger pump into a 2, 5-hexanedione aqueous solution and a 20% sodium hydroxide solution, and setting the flow rate to be 10-18 mL/min;
s3, placing a 1L four-mouth bottle at the outlet of the reactor, cooling the heat conduction oil by external bath at 0-5 ℃, stopping reaction and sampling after receiving the reaction liquid for 30min, extracting with acetic acid, and performing GC analysis.
Further, the molar ratio of the sodium hydroxide to the 2, 5-hexanedione is between 0.9 and 2.1.
Further, the coil pipe type reactor is placed in an oil bath pan at the temperature of 122-130 ℃.
Further, the flow rate in the S2 is 10-14 mL/min.
Furthermore, a pipeline for introducing and discharging heat conduction oil is arranged outside the oil bath pot.
Compared with the prior art, the invention has the beneficial effects that:
1) the continuous reaction technology is adopted, and the selectivity of the reaction is regulated and controlled by adjusting the molar ratio, the feeding rate and the retention time of 2 groups of materials; and collecting and cooling the reaction liquid after the reaction is finished, so as to avoid the rapid decomposition of the product in the hot alkali liquid.
2) The reaction is carried out at a lower temperature by using water as a solvent, so that the pollution to the environment is reduced, and the energy consumption is reduced.
Drawings
The disclosure of the present invention is illustrated with reference to the accompanying drawings. It is to be understood that the drawings are designed solely for the purposes of illustration and not as a definition of the limits of the invention. In the drawings, like reference numerals are used to refer to like parts. Wherein:
fig. 1 shows schematically a flow diagram of a coil-type microreactor apparatus according to the invention.
FIG. 2 shows the preparation of 3-methyl-2-cyclopenten-1-one1H-NMR spectrum.
Detailed Description
It is easily understood that according to the technical solution of the present invention, a person skilled in the art can propose various alternative structures and implementation ways without changing the spirit of the present invention. Therefore, the following detailed description and the accompanying drawings are merely illustrative of the technical aspects of the present invention, and should not be construed as all of the present invention or as limitations or limitations on the technical aspects of the present invention.
Simulation production
To 2, 5-hexanedione (120.0g) was added deionized water (300mL,2.5vol) and stirred well as record solution A. Deionized water (400mL) was added to sodium hydroxide (100.0g) and stirred well as denoted as solution B (i.e., 20% aqueous sodium hydroxide).
The coil reactor was installed and placed in an oil bath pan with the external temperature raised to 125 ℃. The material suction nozzles of plunger pump MPF1002 (hereinafter referred to as pump 1) and plunger pump TBP5002T (hereinafter referred to as pump 2) were immersed under the liquid surfaces of solution A and solution B, respectively. Setting the flow rates of the pump 1 and the pump 2 to be 12.0mL/min, simultaneously starting the two pumps, and injecting the solution A and the solution B into the reactor from the two feed inlets of the reactor for reaction.
Collecting effluent liquid at the outlet of the reactor into a 1L four-mouth bottle, and cooling by external bath at 0-5 ℃. After receiving the reaction liquid for 30min, stopping the reaction, sampling, extracting with acetic acid, and performing GC analysis, wherein the product accounts for 80.9%. The reaction solution was extracted with ethyl acetate, concentrated to remove the solvent, and distilled under reduced pressure to give 63.2g of pure product, yield 72.9%, purity 99.4%.
Molar ratio optimization
The reaction substrates of the invention are 2, 5-hexanedione and sodium hydroxide which are aqueous solutions. The molar ratio of the reaction substrates can be regulated by controlling the concentration of one substrate to be constant and regulating the concentration of the other substrate. In the actual optimization, the concentration of sodium hydroxide is kept unchanged at 20%, and only the concentration of the raw material 2, 5-hexanedione is changed.
Examples 1 to 1
To 2, 5-hexanedione (120.0g) was added deionized water (300mL,2.5vol) and stirred well as record solution A. Deionized water (400mL) was added to sodium hydroxide (100.0g) and stirred well as denoted as solution B (i.e., 20% aqueous sodium hydroxide). The coil reactor was installed and placed in an oil bath pan with the external temperature raised to 125 ℃. The material suction nozzles of the plunger pump 1 (hereinafter referred to as pump 1) and the plunger pump 2 (hereinafter referred to as pump 2) were immersed under the liquid surfaces of the solution a and the solution B, respectively. Setting the flow rates of the pump 1 and the pump 2 to be 12.0mL/min, simultaneously starting the two pumps, and injecting the solution A and the solution B into the reactor from the two feed inlets of the reactor for reaction. Collecting effluent liquid at the outlet of the reactor into a 250mL four-mouth bottle, and cooling by external bath at 0-5 ℃. After receiving the reaction solution for 5min, the reaction was stopped and a sample was taken, extracted with ethyl acetate and analyzed by GC. The molar ratio of sodium hydroxide to 2, 5-hexanedione was 2.1: 1.
Examples 1 to 2
To 2, 5-hexanedione (120.0g,1.0eq) was added deionized water (222mL,1.85vol) and stirred well as solution A. Other conditions were the same as in example 1-1. After receiving the reaction solution for 5min, the reaction was stopped and a sample was taken, extracted with ethyl acetate and analyzed by GC. The molar ratio of sodium hydroxide to 2, 5-hexanedione was 1.7: 1.
Examples 1 to 3
To 2, 5-hexanedione (120.0g,1.0eq) was added deionized water (138mL,1.15vol) and stirred well as solution A. Other conditions were the same as in example 1-1. After receiving the reaction solution for 5min, the reaction was stopped and a sample was taken, extracted with ethyl acetate and analyzed by GC. The molar ratio of sodium hydroxide to 2, 5-hexanedione was 1.3: 1.
Examples 1 to 4
To 2, 5-hexanedione (120.0g,1.0eq) was added deionized water (51.6mL,0.43vol) and stirred well and was taken as solution A. Other conditions were the same as in example 1-1. After receiving the reaction solution for 5min, the reaction was stopped and a sample was taken, extracted with ethyl acetate and analyzed by GC. The molar ratio of sodium hydroxide to 2, 5-hexanedione was 0.9: 1.
The reaction conditions and experimental results for examples 1-1 to 1-4 are shown in the following table.
Calculating the molar ratio:
the density of the 20% aqueous sodium hydroxide solution was 1.22g/cm3, so the moles of sodium hydroxide in the solution
The density of the 2, 5-hexanedione is 0.973g/cm3, the volume of the 2, 5-hexanedione aqueous solution is approximate to the volume of the solvent water, if 1g2, 5-hexanedione is dissolved in water, the volume of the hexanedione is 1/0.973, the volume number of the solution is 1/0.973+ n, wherein n is the mass ratio of water to hexanedione, and the mole number of the 2, 5-hexanedione in the 1mL2, 5-hexanedione aqueous solution is not difficult to obtain
1/0.973g cm-3/(1/0.973+ n) × 0.973/M, where n is the mass ratio of water to 2, 5-hexanedione and M is the molar mass of 2, 5-hexanedione.
Flow rate optimization
Example 2-1
The other conditions are the same as the example 1-1, the flow rates of the pump 1 and the pump 2 are both 10.0mL/min, the two pumps are simultaneously started, and the solution A and the solution B are respectively injected into the reactor from two feed inlets of the reactor for reaction. Collecting effluent liquid at the outlet of the reactor into a 250mL four-mouth bottle, and cooling by external bath at 0-5 ℃. After receiving the reaction solution for 5min, the reaction was stopped and a sample was taken, extracted with ethyl acetate and analyzed by GC.
Examples 2 to 2
The other conditions were the same as in example 1-1, the flow rates of pump 1 and pump 2 were set to 14.0mL/min, and both pumps were started simultaneously to inject solution A and solution B from the two inlets of the reactor into the reactor for reaction. Collecting effluent liquid at the outlet of the reactor into a 250mL four-mouth bottle, and cooling by external bath at 0-5 ℃. After receiving the reaction solution for 5min, the reaction was stopped and a sample was taken, extracted with ethyl acetate and analyzed by GC.
Examples 2 to 3
The other conditions are the same as the example 1-1, the flow rates of the pump 1 and the pump 2 are both 16.0mL/min, the two pumps are simultaneously started, and the solution A and the solution B are respectively injected into the reactor from two feed inlets of the reactor for reaction. Collecting effluent liquid at the outlet of the reactor into a 250mL four-mouth bottle, and cooling by external bath at 0-5 ℃. After receiving the reaction solution for 5min, the reaction was stopped and a sample was taken, extracted with ethyl acetate and analyzed by GC.
Examples 2 to 4
The other conditions are the same as the example 1-1, the flow rates of the pump 1 and the pump 2 are both set to be 18.0mL/min, the two pumps are simultaneously started, and the solution A and the solution B are respectively injected into the reactor from the two feed inlets of the reactor for reaction. Collecting effluent liquid at the outlet of the reactor into a 250mL four-mouth bottle, and cooling by external bath at 0-5 ℃. After receiving the reaction solution for 5min, the reaction was stopped and a sample was taken, extracted with ethyl acetate and analyzed by GC.
The reaction conditions and experimental results for examples 2-1 to 2-4 are shown in the following table.
| Examples | Molar ratio of | Total flow rate/mL/min | Reaction temperature | Raw material, product content (GC)/% in the reaction solution |
| 2-1 | 2.1 | 20.0 | 125 | 2.7/80.0 |
| 2-2 | 2.1 | 28.0 | 125 | 3.1/78.7 |
| 2-3 | 2.1 | 32.0 | 125 | 4.4/78.5 |
| 2-4 | 2.1 | 36.0 | 125 | 4.4/78.5 |
Temperature optimization
Example 3-1
The reaction was carried out under the same conditions as in example 1-1 except that the oil bath temperature was 120 ℃. Collecting effluent liquid at the outlet of the reactor into a 250mL four-mouth bottle, and cooling by external bath at 0-5 ℃. After receiving the reaction solution for 5min, the reaction was stopped and a sample was taken, extracted with ethyl acetate and analyzed by GC.
Examples 3 to 2
The reaction was carried out under the same conditions as in example 1-1 except that the oil bath temperature was 122 ℃. Collecting effluent liquid at the outlet of the reactor into a 250mL four-mouth bottle, and cooling by external bath at 0-5 ℃. After receiving the reaction solution for 5min, the reaction was stopped and a sample was taken, extracted with ethyl acetate and analyzed by GC.
Examples 3 to 3
The reaction was carried out under the same conditions as in example 1-1 except that the oil bath temperature was 130 ℃. Collecting effluent liquid at the outlet of the reactor into a 250mL four-mouth bottle, and cooling by external bath at 0-5 ℃. After receiving the reaction solution for 5min, the reaction was stopped and a sample was taken, extracted with ethyl acetate and analyzed by GC.
The reaction conditions and experimental results for examples 3-1 to 3-3 are shown in the following table.
| Examples | Molar ratio of | Total flow rate/mL/min | Reaction temperature | Raw material, product content (GC)/% in the reaction solution |
| 3-1 | 2.1 | 24.0 | 120 | 19.5/60.5 |
| 3-2 | 2.1 | 24.0 | 122 | 5.1/76.5 |
| 3-3 | 2.1 | 24.0 | 130 | 4.5/71.0 |
The liquid in the pipeline is obviously gasified
Compared with the traditional process result
The following table shows the results of comparing the actual production data with the synthesis carried out using the prior art, wherein the synthetic route of the invention has clear advantages:
it can be seen from the above table that the selectivity of the reaction is regulated by adopting the continuous reaction technology and adjusting the molar ratio, the feeding rate and the residence time of the 2 groups of materials; the reaction liquid after the reaction is finished is collected and cooled, so that the product can be effectively prevented from being rapidly decomposed in the hot alkali liquor. The water is used as a solvent, and the reaction is carried out at a lower temperature, so that the pollution to the environment can be effectively reduced, and the energy consumption is reduced.
The technical scope of the present invention is not limited to the above description, and those skilled in the art can make various changes and modifications to the above-described embodiments without departing from the technical spirit of the present invention, and such changes and modifications should fall within the protective scope of the present invention.
Claims (5)
1. A preparation method of 3-methyl-2-cyclopentene-1-ketone comprises a coil pipe type reactor and two plunger pumps, and is characterized in that the output ends of the plunger pumps are connected with the coil pipe type reactor, and the coil pipe type reactor is placed in an oil bath kettle at 120-130 ℃; the preparation method comprises the following steps:
s1, preparing a 2, 5-hexanedione aqueous solution and a 20% sodium hydroxide solution;
s2, respectively immersing the plunger pump into a 2, 5-hexanedione aqueous solution and a 20% sodium hydroxide solution, and setting the flow rate to be 10-18 mL/min;
s3, placing a 1L four-mouth bottle at the outlet of the reactor, cooling the heat conduction oil by external bath at 0-5 ℃, stopping reaction and sampling after receiving the reaction liquid for 30min, extracting with acetic acid, and performing GC analysis.
2. The method for preparing 3-methyl-2-cyclopentene-1-one according to claim 1, wherein the molar ratio of sodium hydroxide to 2, 5-hexanedione is 0.9 to 2.1.
3. The method for preparing 3-methyl-2-cyclopentene-1-one according to claim 1, wherein the coil reactor is placed in an oil bath at 122 to 130 ℃.
4. The method for preparing 3-methyl-2-cyclopentene-1-one according to claim 1, wherein a flow rate in S2 is 10-14 mL/min.
5. The method for preparing 3-methyl-2-cyclopentene-1-one according to claim 1, wherein a pipe for introducing and discharging heat transfer oil is further provided outside the oil bath pan.
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5276199A (en) * | 1993-02-11 | 1994-01-04 | Ethyl Corporation | Process for preparing cyclopentenones |
| US5763664A (en) * | 1995-12-01 | 1998-06-09 | Albemarle Corporation | Process for preparing cyclopentenones |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5276199A (en) * | 1993-02-11 | 1994-01-04 | Ethyl Corporation | Process for preparing cyclopentenones |
| US5763664A (en) * | 1995-12-01 | 1998-06-09 | Albemarle Corporation | Process for preparing cyclopentenones |
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