Synthesis method of methyl cis-dihydrojasmonate
By using a gas circulation device and catalyst recovery technology, the synthesis steps of methyl dihydrojasmonate were simplified, production costs were reduced, yield and catalyst recovery rate were increased, continuous production was achieved, and the problems of high cost and low yield in existing technologies were solved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- TENGZHOU XINHE BIOTECHNOLOGY CO LTD
- Filing Date
- 2025-12-31
- Publication Date
- 2026-05-12
Smart Images
Figure CN122010731A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of fragrance raw material synthesis technology, specifically a method for synthesizing methyl cis-dihydrojasmonic acid. Background Technology
[0002] Currently, the industrial production route for methyl dihydrojasmonic acid mainly starts from cyclopentanone and n-pentanal, proceeding through aldol condensation and strong acid isomerization to obtain the key intermediate 2-pentyl-2-cyclopentenone. Dimethyl malonate is then added to the 2-pentyl-2-cyclopentenone intermediate, followed by decarboxylation to obtain the methyl dihydrojasmonic acid product. This synthesis process is complex, involves numerous purification steps, has high production costs, cannot achieve continuous production, and has a low product recovery rate.
[0003] Because the preparation process involves multiple steps and requires a relatively large amount of catalyst, catalyst recovery and improved catalytic efficiency are key to reducing the cost of producing methyl cis-dihydrojasmonate. Simplifying the preparation steps, increasing the yield, and improving catalyst recovery can significantly reduce production costs and increase production efficiency. Summary of the Invention
[0004] The purpose of this invention is to provide a method for synthesizing methyl cis-dihydrojasmonic acid, which solves the problems of high cost, low yield and low catalyst recovery rate in the existing preparation of methyl cis-dihydrojasmonic acid by simplifying the steps, improving the catalyst recovery rate and realizing continuous production.
[0005] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution: A method for synthesizing methyl cis-dihydrojasmonic acid, comprising the following steps: S1: Dissolve 1-heptyne in toluene and discharge it into the first reaction vessel. Add cobalt catalyst and use a gas circulation device to discharge a mixture of 1-bromo-ethylene and carbon monoxide into the first reaction vessel and stir the reaction to generate a mixed solution of 2-pentyl-4-bromo-2-cyclopentenone. After the reaction is completed, discharge it into the first catalyst recovery vessel. S2: Add triphenylphosphine solution to the first catalyst recovery tank to generate catalyst precipitate. Discharge and recover the catalyst precipitate at the bottom of the first catalyst recovery tank. Then, perform fractional distillation to distill and cool 1-heptyne to obtain 2-pentyl-4-bromo-2-cyclopentenone solution, and discharge it into the layered tank. S3: Anhydrous methanol is discharged into the layered tank. 2-pentyl-4-bromo-2-cyclopentenone dissolves in the anhydrous methanol to form an upper organic mixed phase and a lower toluene phase. The bottom toluene phase is discharged, and the remaining organic mixed phase is discharged into the second reaction tank. S4: Add an appropriate amount of anhydrous methanol to the second reaction vessel, then discharge dimethyl malonate and slowly add sodium methoxide. Perform a reflux addition reaction at -5-0℃ and continue stirring. After the reaction is completed, heat to carry out a decarboxylation reaction, and then discharge into the second catalyst recovery vessel. Collect methyl 4-bromo-dihydrojasmonic acid by fractional vacuum distillation, and discharge sodium methoxide solution from the bottom. S5: The distilled methyl 4-bromo-dihydrojasmonic acid is discharged into the third reaction vessel. After adding toluene and sodium carbonate, a debromination reaction is carried out to generate a methyl jasmonic acid solution with α,β-double bonds. Then, the methyl jasmonic acid solution with α,β-double bonds is purified. S6: Methyl jasmonate with α,β-double bonds is introduced into the fourth reaction vessel, where a Pt / C catalyst and a halogen curing agent are added, and hydrogen gas is introduced to generate cis-dihydrojasmonate methyl ester.
[0006] Furthermore, the gas circulation device includes an air pump, a gas distribution cylinder, and multiple gas supply pipes. The top of the gas distribution cylinder is provided with a main air inlet pipe, and the bottom is provided with a ring of exhaust branch pipes. The outlet end of the air pump is connected to the main air inlet pipe through a first flexible hose, and each exhaust branch pipe is connected to the bottom end of a gas supply pipe through a second flexible hose. The bottom of the first reaction vessel is provided with a detachable arc-shaped base cover. A first reaction discharge pipe is provided at the center of the arc-shaped base cover. A gas supply pipe is inserted through the arc-shaped base cover around the first reaction discharge pipe. An exhaust head is screwed onto the end of the gas supply pipe inside the arc-shaped base cover. The exhaust head has fine exhaust holes evenly distributed. The first reaction vessel is sealed with a first reaction vessel cover. The first reaction vessel cover is equipped with four first solenoid valve tubes. A mechanically sealed first stirring device is installed in the middle of the first reaction vessel cover. The first stirring device is inserted into the first reaction vessel. One of the first solenoid valve tubes is used to add a 1-heptyne solution dissolved in toluene, and a catalyst discharge branch pipe is connected to the 1-heptyne solution delivery pipe. The second and third first solenoid valve tubes are the inlet and outlet pipes, respectively. The fourth first solenoid valve tube is connected to the inlet of the gas pump via a third flexible hose.
[0007] Furthermore, a mixture of 1-bromoethylene and carbon monoxide is introduced into the first reaction vessel through the second first solenoid valve tube, and gas is discharged out through the third first solenoid valve tube to exchange the gas in the first reaction vessel. Then, a 1-heptyne solution dissolved in toluene and a cobalt catalyst solution are introduced into the first reaction vessel. The solenoid valves in the first and third first solenoid valve tubes are closed. The second first solenoid valve tube continues to pressurize the first reaction vessel, so that the gas pressure in the first reaction vessel reaches 2-6 atmospheres. Then, the solenoid valve in the second first solenoid valve tube is closed, and the first reaction vessel is heated to 60-95°C and reacted for 18-24 hours. The gas pump circulates and draws gas from the first reaction tank into the gas distribution cylinder, and then distributes the gas evenly to the bottom of the first reaction tank through multiple gas supply pipes, so that the gas can fully contact the reaction liquid. The gas pressure inside the first reaction vessel is monitored in real time. When the gas pressure is lower than the preset value, the solenoid valve in the second solenoid valve tube of the first solenoid valve is opened, and gas is supplied to the first reaction vessel to replenish the pressure.
[0008] Furthermore, the bottom of the first catalyst recovery tank is provided with a sedimentation cylinder, and a discharge pipe is provided near the top of the sedimentation cylinder. The top of the first catalyst recovery tank is provided with a first recovery tank cover, and four second solenoid valve pipes are provided on the first recovery tank cover. A second stirring device is provided in the middle of the first recovery tank cover. The first reaction discharge pipe is connected to the first second solenoid valve pipe. The second second solenoid valve pipe is a distillation pipe. The third second solenoid valve pipe is a feeding pipe. The fourth second solenoid valve pipe is a pressure relief pipe. When the solenoid valve in the fourth second solenoid valve tube is opened, the first reaction vessel discharges the reaction solution into the first catalyst recovery vessel. After the reaction solution is discharged, the first second solenoid valve tube is closed, and triphenylphosphine solution is discharged into the first catalyst recovery vessel from the third second solenoid valve tube. The solenoid valve in the third second solenoid valve tube is closed, and the mixture is stirred at room temperature for 30 minutes to allow the triphenylphosphine to react with the cobalt catalyst to form a catalyst precipitate combining triphenylphosphine and the cobalt catalyst. The catalyst precipitate settles into the precipitation cylinder. The valve at the bottom of the precipitation cylinder is opened to discharge the solution in the precipitation cylinder. The solenoid valve at the bottom of the precipitation cylinder is closed, and the first catalyst recovery vessel is started to heat slowly at a reduced pressure of 3-5℃ / min to 90-95℃. This temperature is maintained for 10-15 minutes to recover toluene and 1-heptyne.
[0009] Furthermore, a 90° inclined T-shaped tee is connected to the discharge pipe at the bottom of the stratified tank. The top interface of the 90° inclined T-shaped tee is connected to the discharge pipe at the bottom of the stratified tank, and a glass tube is connected to the bottom interface of the 90° inclined T-shaped tee. A solenoid valve is installed in the side pipe at the middle position of the 90° inclined T-shaped tee, and a solenoid valve is installed at the bottom end of the glass tube. The top of the stratified tank is covered with a stratified tank cover, and four third solenoid valve pipes are provided on the stratified tank cover. A third stirring device is installed in the middle position of the stratified tank cover. The first third solenoid valve pipe is connected to the discharge pipe, the second third solenoid valve pipe is an anhydrous methanol addition pipe, and the third and fourth third solenoid valve pipes are respectively a venting pipe and a venting pipe. After the first catalyst recovery tank has discharged the raw material into the stratification tank, the solenoid valve in the first third solenoid valve tube is closed, and the second third solenoid valve tube begins to discharge anhydrous methanol into the stratification tank for stirring and dissolution. Stirring is carried out for 20-30 minutes, and then the mixture is allowed to stand and separate. A light transmittance detector is installed next to the glass tube. The solenoid valve at the bottom of the glass tube is opened to slowly discharge the toluene phase. When the light transmittance detector detects a significant light transmittance difference in the glass tube, the solenoid valve in the glass tube is closed, and the solenoid valve in the upper part of the inclined 90° T-shaped three-way pipe is opened to discharge the organic mixed phase into the second reaction vessel.
[0010] Furthermore, the top of the second reaction vessel is provided with a second reaction vessel cover, and the second reaction vessel cover is provided with five fourth solenoid valve tubes. A fourth stirring device is provided in the middle of the second reaction vessel cover. The first fourth solenoid valve tube is a liquid inlet tube, the second fourth solenoid valve tube is a methanol inlet tube, the third fourth solenoid valve tube is a sodium methoxide inlet tube, and the fourth and fifth fourth solenoid valve tubes are respectively a gas exchange inlet tube and a gas outlet tube. After the organic mixed phase is discharged into the second reaction vessel by the layered tank, the solenoid valve in the first fourth solenoid valve tube is closed, and the second fourth solenoid valve tube adds an appropriate amount of anhydrous methanol into the second reaction vessel. The temperature inside the second reaction vessel is 0-5℃. At this time, sodium methoxide is slowly discharged into the second reaction vessel through the third fourth solenoid valve tube while continuously stirring and mixing. The stirring reaction is carried out for 2-4 hours, and an appropriate amount of anhydrous methanol is added. Then, the temperature of the second reaction vessel is adjusted to 60-70℃, and the methanol reflux reaction is carried out for 20-24 hours. After the decarboxylation reaction is completed in the second reaction vessel, the entire reaction liquid is discharged into the second catalyst recovery tank.
[0011] Furthermore, each of the second reaction tanks has bottom side pipes of 2-3 layered tanks connected to the liquid inlet end of the second reaction tank through branch pipes, and each of the second catalyst recovery tanks has 4-8 liquid inlet pipes evenly distributed on the tank wall near the top, and each liquid inlet pipe is connected to a discharge pipe at the bottom of a second reaction tank.
[0012] Furthermore, the top of the second catalyst recovery tank is covered with a second catalyst recovery tank cover, and the second catalyst recovery tank cover is equipped with four fifth solenoid valve tubes. A fifth stirring device is installed in the middle of the second catalyst recovery tank cover. The first fifth solenoid valve tube is a nitrogen inlet tube, the second fifth solenoid valve tube is a methanol evaporation tube, the third fifth solenoid valve tube is a low-boiling impurity evaporation tube, and the fourth fifth solenoid valve tube is a methyl 4-bromo-dihydrojasmonic acid evaporation tube. The second catalyst recovery tank is first heated to 60-80℃ to evaporate the methanol, and then vacuum distillation is started; Vacuum distillation steps: The third solenoid valve tube evacuates gas to reduce the pressure in the second catalyst recovery tank; the first solenoid valve tube adds a small amount of nitrogen; the tank is heated to 80-120°C to distill off residual low-boiling impurities; the solenoid valve in the third solenoid valve tube is closed, and the solenoid valve in the fourth solenoid valve tube evacuates gas to reduce the pressure; the tank is heated to 140-160°C to distill off methyl 4-bromo-dihydrojasmonate; the tank is then cooled to remove the sodium methoxide mixture from the bottom of the second catalyst recovery tank.
[0013] Furthermore, the fourth of the fifth solenoid valve tubes is connected to the liquid inlet of multiple third reaction tanks via branch pipes. The structure of the third reaction tanks is the same as that of the second reaction tanks. Five sixth solenoid valve tubes are provided on the tank cover at the top of the third reaction tanks. The first of the sixth solenoid valve tubes is connected to the branch pipes. The second and third of the sixth solenoid valve tubes are the gas inlet and gas outlet, respectively. The fourth of the sixth solenoid valve tubes is the solvent inlet tube, and the fifth of the sixth solenoid valve tubes is the sodium carbonate inlet tube. Toluene solvent is discharged into the third reaction vessel through the fourth solenoid valve tube to dissolve methyl 4-bromo-dihydrojasmonic acid. Then, an appropriate amount of sodium carbonate is slowly added through the fifth solenoid valve tube to dissolve the methyl 4-bromo-dihydrojasmonic acid. The reaction is stirred and carried out at a temperature of 110-115°C. Toluene is refluxed for 8-12 hours to obtain methyl 4-jasmonic acid product with α,β-double bonds.
[0014] Furthermore, for every two of the third reaction vessels, the product is transferred to a fourth reaction vessel, and nano-sized Pt particles loaded on the surface of powdered activated carbon catalyst are added to the fourth reaction vessel, followed by the addition of a halogen curing agent, and the mixture is stirred at room temperature for 30 minutes. After purification, the methyl jasmonate product with α,β-double bonds is discharged into the fourth reaction vessel. The fourth reaction vessel is sealed, and the air inside the fourth reaction vessel is replaced with hydrogen 3-5 times. Hydrogen is introduced until the target pressure of 0.5-1 MPa is reached, the temperature is raised to 30-40℃, the stirring rate is controlled at 300-500 r / min, and the reaction is carried out for 4-6 hours.
[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. In this invention, 1-bromoethylene and carbon monoxide react with 1-heptyne in the first reaction vessel, replacing traditional ethylene with 1-bromoethylene. The resulting product is 2-pentyl-4-bromo-2-cyclopentenone. During the reaction, a mixture of 1-bromoethylene and carbon monoxide is intermittently added to the first reaction vessel. This mixture is discharged into the solution from the bottom of the first reaction vessel via a gas circulation device. The gas bubbles disperse in the reaction solution, ensuring sufficient contact and catalytic reaction, significantly improving reaction efficiency. This method is more efficient than the traditional method of discharging gas into the reaction vessel, where the reaction only occurs well on the surface layer of the solution, with poorer internal reactions.
[0016] 2. In this invention, a triphenylphosphine solution is discharged into the first catalyst recovery tank. The triphenylphosphine reacts with the cobalt catalyst (Co2(CO)8) to form Co2(CO)6(PPh3)2 precipitate. After standing for a period of time, the precipitate is discharged to the bottom. Then, fractional distillation is performed to recover 1-heptyne through distillation and cooling. A large amount of toluene will evaporate along with it. Since it contains a small amount of unreacted 1-heptyne, the 1-heptyne is evaporated. The remaining 2-pentyl-4-bromo-2-cyclopentenone solution containing toluene is discharged into the separation tank. Methanol is used (because 1-heptyne is soluble in methanol, it is not conducive to subsequent dissolution and separation, so it needs to be distilled first). The toluene is dissolved and separated into layers (distillation recovery). After separation, the toluene is at the bottom and is discharged separately through the separation and diversion discharge unit. When the toluene is discharged downward from the glass tube, a slightly yellow color (the color of 2-pentyl-4-bromo-2-cyclopentenone) appears inside the glass tube. The surface is basically cleared of toluene, and the discharge stops. The side pipe of the 90° T-shaped three-way pipe discharges only the 2-pentyl-4-bromo-2-cyclopentenone dissolved in methanol, which greatly improves the recovery and extraction of 2-pentyl-4-bromo-2-cyclopentenone. Moreover, the subsequent reaction requires methanol as a solvent, so the methanol solvent can be directly discharged into the second reaction tank without the need for separation.
[0017] 3. This invention is equipped with at least four second reaction tanks around the second catalyst recovery tank. The second reaction tanks carry out the reaction of dimethyl malonate with 2-pentyl-4-bromo-2-cyclopentenone. The decarboxylation reaction after the reaction also takes place in the second reaction tank. The total reaction time is close to 20 hours (or even longer). When the second catalyst recovery tank recovers the product, the time may be less than two hours. With cleaning or cooling treatment, it takes a maximum of 3 hours. By configuring multiple second reaction tanks, the product can be circulated into the second catalyst recovery tank, realizing continuous reaction, producing intermediate products, and improving production efficiency.
[0018] 4. The present invention is equipped with a catalyst recovery structure in all continuous reaction equipment, which improves the catalyst recovery efficiency and reduces the catalyst usage cost.
[0019] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description
[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0021] Figure 1 This is a flowchart of a method for synthesizing methyl cis-dihydrojasmonic acid.
[0022] Figure 2 This is a flowchart illustrating the synthetic reaction equation for methyl cis-dihydrojasmonic acid.
[0023] Figure 3 This is a schematic diagram of the equipment used to synthesize methyl cis-dihydrojasmonic acid.
[0024] Figure 4 This is a structural diagram showing the locations of the first reaction vessel and the first catalyst recovery vessel.
[0025] Figure 5 This is a schematic diagram showing the explosive structure of the locations of the first reaction vessel and the first catalyst recovery vessel.
[0026] Figure 6 This is a schematic diagram of the location and structure of the arc-shaped base cover.
[0027] Figure 7 This is a schematic diagram of the exhaust head.
[0028] Figure 8 This is a structural diagram showing the locations of the layered tank, the second reaction tank, and the second catalyst recovery tank.
[0029] In the diagram: 1. First reaction vessel; 11. Vessel body of the first reaction vessel; 12. Arc-shaped base cover; 121. First reaction discharge pipe; 13. First reaction vessel cover; 131. First stirring device; 14. Gas distribution cylinder; 15. Gas supply pipe; 151. Thin pipe; 16. Exhaust head; 161. Exhaust orifice; 2. First catalyst recovery vessel; 21. Vessel body of the first catalyst recovery vessel; 22. First recovery vessel cover; 221. Second stirring device; 23. Sedimentation cylinder; 231. Discharge pipe one 3. Layered Tank; 31. Tank Body of Layered Tank; 32. Layered Diversion Discharge Unit; 321. Inclined 90° T-shaped Tee Pipe; 322. Side Connecting Pipe; 323. Glass Tube; 33. Layered Tank Cover; 34. Third Stirring Device; 4. Second Reaction Tank; 41. Tank Body of Second Reaction Tank; 42. Second Reaction Tank Cover; 43. Fourth Stirring Device; 5. Second Catalyst Recovery Tank; 51. Tank Body of Second Catalyst Recovery Tank; 52. Second Catalyst Recovery Tank Cover; 53. Fifth Stirring Device. Detailed Implementation
[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0031] like Figures 1-8 As shown, a method for synthesizing methyl cis-dihydrojasmonic acid includes the following steps: S1: Dissolve 1-heptyne in toluene and discharge it into the first reaction vessel 1. Add a measured amount of cobalt catalyst (Co2(CO)8). Using a gas circulation device, discharge a mixture of 1-bromoethylene and carbon monoxide into the first reaction vessel 1 and stir the reaction to generate a mixed solution of 2-pentyl-4-bromo-2-cyclopentenone. After the reaction is complete, discharge it into the first catalyst recovery vessel 2. The cobalt catalyst solution must be diluted with toluene before being added to the reaction system and mixed with the 1-heptyne solution dissolved in toluene before being discharged. The stirred reaction requires pressurization.
[0032] S2: A measured amount of triphenylphosphine solution is added to the first catalyst recovery tank 2 to generate a catalyst precipitate. The catalyst precipitate at the bottom of the first catalyst recovery tank 2 is discharged for recovery. Then, 1-heptyne is distilled and cooled for recovery to obtain a 2-pentyl-4-bromo-2-cyclopentenone solution, which is discharged into the layered tank 3. Triphenylphosphine reacts with Co2(CO)8 to prepare the precipitated catalyst product. After discharge, the catalyst precipitate product is recovered. The catalyst precipitate product is heated to 80°C in a CO atmosphere, where it is replaced by CO and reverts to the active species Co2(CO)8, which can be reused.
[0033] Since the reaction product contains unreacted 1-heptyne, which is soluble in methanol, if a uniform fractional distillation is used to completely distill off the solvent toluene, some 2-pentyl-4-bromo-2-cyclopentenone will remain, resulting in a reduced recovery rate of 2-pentyl-4-bromo-2-cyclopentenone. Therefore, distillation is stopped after distilling off only a small amount of 1-heptyne, and subsequent methanol dissolution and layering purification of 2-pentyl-4-bromo-2-cyclopentenone is carried out.
[0034] S3: Anhydrous methanol is discharged into the layered tank 3. 2-pentyl-4-bromo-2-cyclopentenone dissolves in the anhydrous methanol to form an upper organic mixed phase and a lower toluene phase. The bottom toluene phase is discharged, and the remaining organic mixed phase is discharged into the second reaction tank 4. After the toluene is completely separated, the 2-pentyl-4-bromo-2-cyclopentenone dissolved in the anhydrous methanol just meets the requirements of the subsequent reaction. It can be directly discharged into the second reaction tank 4 for use.
[0035] S4: Add an appropriate amount of anhydrous methanol to the second reaction vessel 4, then discharge dimethyl malonate and slowly add sodium methoxide. Perform a reflux addition reaction at -5 to 0°C with continuous stirring. After the reaction is complete, heat to carry out a decarboxylation reaction, then discharge into the second catalyst recovery vessel 5. Collect methyl 4-bromo-dihydrojasmonic acid by fractional vacuum distillation, and discharge sodium methoxide solution from the bottom. During the low-temperature reaction, dimethyl malonate mainly adds to the double bond position on 2-pentyl-4-bromo-2-cyclopentenone, but the dimethyl malonate group also needs decarboxylation. To increase the amount of reaction product, decarboxylation needs to be carried out at a low temperature (60-70°C), but the reaction time is long, up to 20 hours. Therefore, multiple second reaction vessels 4 are equipped around the second catalyst recovery vessel 5 to achieve continuous reaction and replenishment of intermediate products.
[0036] S5: The distilled methyl 4-bromo-dihydrojasmonic acid is discharged into the third reaction vessel. After adding toluene and sodium carbonate, a debromination reaction is carried out to generate a methyl jasmonic acid solution with α,β-double bonds. Then, the methyl jasmonic acid solution with α,β-double bonds is purified. S6: Methyl jasmonate with α,β-double bonds is introduced into the fourth reaction vessel, where a Pt / C catalyst and a halogen curing agent are added, and hydrogen gas is introduced to generate cis-dihydrojasmonate methyl ester.
[0037] Steps S5 and S6 are routine reactions and will not be described in detail here.
[0038] The gas circulation device includes an air pump, a gas distribution cylinder 14, and multiple gas supply pipes 15. The top of the gas distribution cylinder 14 is provided with a main air inlet pipe, and the bottom is provided with a ring of exhaust branch pipes. The outlet end of the air pump is connected to the main air inlet pipe through a first hose, and each exhaust branch pipe is connected to the bottom end of a gas supply pipe 15 through a second hose. The bottom of the first reaction vessel 1 is provided with a detachable arc-shaped base cover 12. The center of the arc-shaped base cover 12 is provided with a first reaction discharge pipe 121. A ring of gas supply pipe 15 is inserted through the arc-shaped base cover 12 around the first reaction discharge pipe 121. An exhaust head 16 is screwed to the end of the gas supply pipe on the inner side of the arc-shaped base cover 12. The exhaust head 16 has evenly distributed exhaust holes 161. The first reaction vessel 1 is sealed with a first reaction vessel cover 13. The first reaction vessel cover 13 is equipped with four first solenoid valve tubes. A mechanically sealed first stirring device 131 is installed in the middle of the first reaction vessel cover 13. The first stirring device 131 is inserted into the first reaction vessel 1. One of the first solenoid valve tubes is used to add a 1-heptyne solution dissolved in toluene, and a catalyst discharge branch pipe is connected to the 1-heptyne solution delivery pipe. The second and third first solenoid valve tubes are the inlet and outlet pipes, respectively. The fourth first solenoid valve tube is connected to the inlet of the gas pump via a third flexible hose.
[0039] Traditional methods use in-tank pressurization to increase the solubility of the 1-bromoethylene and carbon monoxide mixture in the reaction liquid, but the reaction mainly concentrates on the surface, resulting in a long reaction time and low yield. This invention provides appropriate pressurization, but the gas is circulated and discharged from the bottom of the first reaction tank 1. The gas flows upward from the bottom of the reaction liquid, prolonging the contact time between the gas and the reaction liquid and improving reaction efficiency. The amount of gas decreases during the reaction, and the gas pressure drops. When the gas pressure drops to a set value, the 1-bromoethylene and carbon monoxide mixture is continuously added to increase the pressurization and improve reaction efficiency. The entire process shortens the overall preparation time of 2-pentyl-4-bromo-2-cyclopentenone (when the yield is above 85%).
[0040] The reaction pathway is a cobalt / rhodium-catalyzed Pauson-Khand cycloaddition reaction, which generates 2-pentyl-4-bromo-2-cyclopentenone.
[0041] During the gas circulation process, the gas at the top of the first reaction tank 1 is drawn away by the gas pump and discharged into the gas distribution cylinder 14. Since the bottom of the gas distribution cylinder 14 is equipped with multiple thin exhaust branches, the gas can be evenly distributed and discharged. The gas is discharged into each gas supply pipe 15, and small bubbles are evenly distributed into the bottom of the first reaction tank 1. Then, under stirring, the bubbles are dispersed into the reaction liquid, contact and coordinate with the catalyst, and then react with 1-heptyne to accelerate the reaction rate.
[0042] The bottom of the air supply pipe 15 has a thin connecting pipe 151 that connects to the second hose. For example... Figure 6 As shown, the exhaust vent 161 can evenly disperse small bubbles that flow upwards. An electronic barometer is installed on the first reaction vessel lid 13. Electronic barometers are also installed on the rear vessel lids.
[0043] A mixture of 1-bromoethylene and carbon monoxide is introduced into the first reaction vessel 1 through the second first solenoid valve tube, and gas is discharged outward through the third first solenoid valve tube to exchange the gas in the first reaction vessel 1. Then, a 1-heptyne solution dissolved in toluene and a cobalt catalyst solution are introduced into the first reaction vessel 1. The solenoid valves in the first and third first solenoid valve tubes are closed. The second first solenoid valve tube continues to pressurize the first reaction vessel 1, so that the gas pressure in the first reaction vessel 1 reaches 2-6 atmospheres. Then, the solenoid valve in the second first solenoid valve tube is closed, and the first reaction vessel 1 is heated to 60-95℃ and reacted for 18-24 hours. The gas pressure inside the first reaction vessel 1 is 2-6 atmospheres, preferably 2-4 atmospheres. Since the gas is circulating, it can better contact the reaction liquid. There is no need to increase the gas dissolution by increasing the pressure to improve the reaction efficiency. Appropriate pressurization ensures that the gas supply is normal during the reaction process. When the gas is reduced, gas is added. Pressurization can realize the circulation process and ensure normal gas supply.
[0044] The gas pump circulates and draws gas from the first reaction tank 1 into the gas distribution cylinder 14, and then distributes the gas evenly to the bottom of the first reaction tank 1 through multiple gas supply pipes 15, so that the gas and the reaction liquid can be fully contacted. The gas pressure inside the first reaction tank 1 is monitored in real time. When the gas pressure is lower than the preset value, the solenoid valve in the second first solenoid valve tube is opened, and exhaust gas is discharged into the first reaction tank 1 to replenish the pressure.
[0045] When the electronic barometer detects that the gas pressure is below 2 atmospheres, a mixture of 1-bromoethylene and carbon monoxide is added to increase the gas supply for the reaction in a timely manner.
[0046] The bottom of the first catalyst recovery tank 2 is provided with a sedimentation cylinder 23. Near the top of the sedimentation cylinder 23, there is a discharge pipe 231. The top of the first catalyst recovery tank 2 is provided with a first recovery tank cover 22. The first recovery tank cover 22 is provided with four second solenoid valve pipes. The middle position of the first recovery tank cover 22 is provided with a second stirring device 221. The first reaction discharge pipe 121 is connected to the first second solenoid valve pipe. The second second solenoid valve pipe is a distillation pipe. The third second solenoid valve pipe is a feeding pipe. The fourth second solenoid valve pipe is a pressure relief pipe. Four second solenoid valves can be opened or closed as needed. The third second solenoid valve is a feed pipe used to add triphenylphosphine, which reacts with the cobalt catalyst to precipitate the cobalt catalyst. The pressure relief pipe is used to exhaust gas or relieve pressure during gas exchange. Pressure relief is required when discharging the reaction liquid into the first catalyst recovery tank 2. When subsequently discharging gas from the first catalyst recovery tank 2, the pressure relief pipe can also reverse to discharge an appropriate amount of nitrogen into the first catalyst recovery tank 2 to expel the air before closing the pressure relief pipe.
[0047] When the solenoid valve in the fourth second solenoid valve tube is opened, the reaction solution is discharged from the first reaction vessel 1 into the first catalyst recovery vessel 2. After the reaction solution is discharged, the first second solenoid valve tube is closed, and triphenylphosphine solution is discharged into the first catalyst recovery vessel 2 from the third second solenoid valve tube. The solenoid valve in the third second solenoid valve tube is closed, and the mixture is stirred at room temperature for 30 minutes to allow the triphenylphosphine to react with the cobalt catalyst to form a catalyst precipitate combining triphenylphosphine and the cobalt catalyst. The catalyst precipitate settles into the precipitation tube 23. The valve at the bottom of the precipitation tube 23 is opened to discharge the solution in the precipitation tube 23. The solenoid valve at the bottom of the precipitation tube 23 is closed, and the first catalyst recovery vessel 2 is started. The mixture is slowly heated and distilled under reduced pressure at 3-5℃ / min until it reaches 90-95℃. This temperature is maintained for 10-15 minutes to recover toluene and 1-heptayne.
[0048] The reaction of triphenylphosphine with cobalt catalyst has been described previously. After the precipitated catalyst is removed, it is recycled by vacuum distillation at 3-5℃ / min, heating to 90-95℃ (and holding at this temperature for 10-15min) to distill off a small amount of 1-heptyne (boiling point around 110℃ at atmospheric pressure). After the small amount of 1-heptyne is distilled off, the next step of separating and removing the toluene solvent can be carried out.
[0049] A 90° inclined T-shaped tee pipe 321 is connected to the discharge pipe at the bottom of the layered tank 3. The top interface of the 90° inclined T-shaped tee pipe 321 is connected to the discharge pipe at the bottom of the layered tank 3. A glass tube 323 is connected to the bottom interface of the 90° inclined T-shaped tee pipe 321. A solenoid valve is installed in the side pipe 322 at the middle position of the 90° inclined T-shaped tee pipe 321. A solenoid valve is installed at the bottom end of the glass tube 323. The top of the layered tank 3 is covered with a layered tank cover 33. Four third solenoid valve pipes are installed on the layered tank cover 33. A third stirring device 34 is installed in the middle position of the layered tank cover 33. The first third solenoid valve pipe is connected to the discharge pipe 231. The second third solenoid valve pipe is the anhydrous methanol addition pipe. The third and fourth third solenoid valve pipes are the air exchange pipe and the air vent pipe, respectively. After the first catalyst recovery tank 2 has discharged the raw material into the layering tank 3, the solenoid valve in the first third solenoid valve tube is closed, and the second third solenoid valve tube begins to discharge anhydrous methanol into the layering tank 3 for stirring and dissolution. Stirring is carried out for 20-30 minutes, and then the mixture is allowed to stand and separate into layers. The inclined 90° T-shaped three-way pipe 321 and glass tube 323 form a stratified and diverted discharge unit 32. The toluene at the bottom is discharged first. The toluene will flow down in the conical glass tube 323 until it is completely discharged. At this time, a color difference will appear (2-pentyl-4-bromo-2-cyclopentenone dissolved in methanol is yellow), indicating that the toluene has been completely discharged. At this time, a relatively pure solution of 2-pentyl-4-bromo-2-cyclopentenone dissolved in methanol can be collected. Open the solenoid valve in the side pipe 322 to discharge it into the second reaction tank 4.
[0050] A light transmittance detector is installed next to the glass tube 323. The solenoid valve at the bottom of the glass tube 323 is opened to slowly discharge the toluene phase. When the light transmittance detector detects a significant light transmittance difference in the glass tube 323, the solenoid valve in the glass tube 323 is closed, and the solenoid valve in the upper part of the inclined 90° T-shaped three-way pipe 321 is opened to discharge the organic mixed phase into the second reaction vessel 4.
[0051] The light transmittance meter can detect the light transmittance of glass tube 323. It can also be set with color acquisition devices, such as a camera, to take pictures and a computer to process and identify the colors. Only the color difference needs to be judged.
[0052] The top of the second reaction tank 4 is provided with a second reaction tank cover 42. The second reaction tank cover 42 is provided with five fourth solenoid valve tubes. The middle position of the second reaction tank cover 42 is provided with a fourth stirring device 43. The first fourth solenoid valve tube is the liquid inlet tube, the second fourth solenoid valve tube is the methanol addition tube, the third fourth solenoid valve tube is the sodium methoxide addition tube, and the fourth and fifth fourth solenoid valve tubes are the gas exchange inlet tube and the gas outlet tube, respectively. The second reaction vessel 4 needs to be replenished with methanol and sodium methoxide (catalyst), which requires two fourth solenoid valve tubes. It also needs to be vented (inert gas protection), which requires two more fourth solenoid valve tubes. Since the addition of the raw material reaction liquid requires one fourth solenoid valve tube, a total of five are needed. The four shown in the figure are for illustration only. In reality, there are not limited to five. The number of fourth solenoid valve tubes can be increased or decreased according to other conditions.
[0053] After the organic mixed phase is discharged into the second reaction tank 4 from the layered tank 3, the solenoid valve in the first fourth solenoid valve tube is closed, and an appropriate amount of anhydrous methanol is added into the second reaction tank 4 through the second fourth solenoid valve tube. The temperature inside the second reaction tank 4 is 0-5℃. At this time, sodium methoxide is slowly discharged into the second reaction tank 4 through the third fourth solenoid valve tube while continuously stirring and mixing. The stirring reaction is carried out for 2-4 hours. An appropriate amount of anhydrous methanol is added again. Then, the temperature inside the second reaction tank 4 is adjusted to 60-70℃, and the methanol reflux reaction is carried out for 20-24 hours. After the decarboxylation reaction is completed in the second reaction tank 4, the entire reaction liquid is discharged into the second catalyst recovery tank 5.
[0054] The addition reaction between dimethyl malonate and 2-pentyl-4-bromo-2-cyclopentenone can be completed at low temperature to generate 2-pentyl-3-malonate dimethyl ester-4-bromo-cyclopentenone (double bond cleavage). Subsequent decarboxylation of the dimethyl malonate group is required. To increase the product yield, a mild reaction (60-70℃) and methanol reflux for 20-24 hours are necessary, resulting in a longer reaction time. However, the catalyst recovery in the second catalyst recovery tank 5 will not exceed 3 hours. Therefore, at least four second reaction tanks 4 are equipped around the second catalyst recovery tank 5 to intermittently discharge the reaction product into the second catalyst recovery tank 5 for distillation of 4-bromo-dihydrojasmonic acid methyl ester and catalyst recovery.
[0055] Each second reaction tank 4 is connected to the bottom side pipe 322 of 2-3 layered tanks 3, and is connected to the liquid inlet end of the second reaction tank 4 through the branch pipe. Each second catalyst recovery tank 5 is provided with 4-8 liquid inlet pipes on the tank wall near the top, and each liquid inlet pipe is connected to the discharge pipe 2 at the bottom of a second reaction tank 4.
[0056] Since the amount of 2-pentyl-4-bromo-2-cyclopentenone produced in one layered tank 3 is relatively small after layering, 2-3 layered tanks 3 can be combined and discharged into the second reaction tank 4 to increase the amount of raw materials for the reaction in the second reaction tank 4.
[0057] The top of the second catalyst recovery tank 5 is covered with a second catalyst recovery tank cover 52. The second catalyst recovery tank cover 52 is equipped with four fifth solenoid valve tubes. A fifth stirring device 53 is installed in the middle of the second catalyst recovery tank cover 52. The first fifth solenoid valve tube is a nitrogen inlet tube, the second fifth solenoid valve tube is a methanol evaporation tube, the third fifth solenoid valve tube is a low-boiling impurity evaporation tube, and the fourth fifth solenoid valve tube is a methyl 4-bromo-dihydrojasmonic acid evaporation tube. The second catalyst recovery tank 5 is first heated to 60-80℃ to evaporate the methanol, and then vacuum distillation is started; Vacuum distillation steps: The third fifth solenoid valve tube evacuates gas to reduce the pressure in the second catalyst recovery tank. A small amount of nitrogen is added to the first fifth solenoid valve tube. The mixture is heated to 80-120°C to distill off residual low-boiling impurities. The solenoid valve in the third fifth solenoid valve tube is closed, and the solenoid valve in the fourth fifth solenoid valve tube is opened to evacuate gas. The mixture is heated to 140-160°C to distill off methyl 4-bromo-dihydrojasmonate. The mixture is then cooled to remove the sodium methoxide mixture from the bottom of the second catalyst recovery tank 5.
[0058] In the second catalyst recovery tank 5, the residual air inside needs to be vented first, and nitrogen protection is applied. Then, reduced pressure fractional distillation is performed. First, methanol is distilled off at atmospheric pressure (distillation at less than 70°C for a period of time is sufficient), and then low-boiling impurities are distilled off. Distillation at 140-160°C under reduced pressure yields methyl 4-bromo-dihydrojasmonic acid. Methyl 4-bromo-dihydrojasmonic acid can be used for subsequent debromination and the breaking of double bonds on the same side to form a cis structure to prepare raw materials.
[0059] The fourth and fifth solenoid valve tubes are connected to the liquid inlet of multiple third reaction tanks through branch pipes. The structure of the third reaction tank is the same as that of the second reaction tank 4. Five sixth solenoid valve tubes are provided on the tank cover at the top of the third reaction tank. The first sixth solenoid valve tube is connected to the branch pipe. The second and third sixth solenoid valve tubes are the gas inlet and gas outlet, respectively. The fourth sixth solenoid valve tube is the solvent addition tube, and the fifth sixth solenoid valve tube is the sodium carbonate addition tube. Toluene solvent is discharged into the third reaction vessel through the fourth and sixth solenoid valves to dissolve methyl 4-bromo-dihydrojasmonic acid. Then, an appropriate amount of sodium carbonate is slowly added through the fifth and sixth solenoid valves to dissolve the methyl 4-bromo-dihydrojasmonic acid. The reaction is stirred and carried out at a temperature of 110-115℃. Toluene is refluxed and the reaction is carried out for 8-12 hours to obtain methyl 4-jasmonic acid with α,β-double bonds.
[0060] To remove bromine from methyl 4-bromo-dihydrojasmonate, it needs to be dissolved in toluene (this solvent is relatively more suitable for the reaction). The methyl jasmonate produced by the reaction with α,β-double bonds has a large π bond due to the C=CC=O structure, which makes the carbon atoms of the pentyl ring in the same plane, and the -pentyl and -acetic acid methyl bonds are more likely to form on the same side.
[0061] For every two third reaction vessels, the product is transferred to a fourth reaction vessel. Nano-sized Pt particles loaded on the surface of powdered activated carbon are added to the fourth reaction vessel, followed by the addition of a halogen curing agent. The mixture is stirred at room temperature for 30 minutes. After purification, the methyl jasmonate product with α,β-double bonds was discharged into the fourth reaction vessel. The fourth reaction vessel was sealed, and the air inside the fourth reaction vessel was replaced with hydrogen 3-5 times. Hydrogen was introduced until the target pressure of 0.5-1 MPa was reached, the temperature was raised to 30-40℃, the stirring rate was controlled at 300-500 r / min, and the reaction was carried out for 4-6 hours.
[0062] Nanoscale Pt particles loaded on the surface of powdered activated carbon can effectively combine with halogen curing agents.
[0063] The same side of the double bond is forced towards the Pt surface, while the other side is far from the catalyst. Due to the large steric hindrance, the cyclopentanone ring and ester side chain of methyl jasmonate cannot adhere closely to the Pt surface. This large steric hindrance results in high adsorption selectivity, making it a core site for cis-addition. Two adsorbed hydrogen atoms attack the two carbon atoms of the double bond sequentially from the same side (the side closer to the Pt surface). After addition, hydrogen atoms are introduced on the same side of the double bond, forming the cis-configured dihydrojasmonate.
[0064] The reaction conditions for the third and fourth reaction vessels are the existing reaction conditions, and the vessel structures can use similar structures as described above without further modification.
[0065] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0066] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.
Claims
1. A method for synthesizing methyl cis-dihydrojasmonic acid, characterized in that, The steps are as follows: S1: Dissolve 1-heptyne in toluene and discharge it into the first reaction tank (1). Add cobalt catalyst and use a gas circulation device to discharge a mixture of 1-bromo-ethylene and carbon monoxide into the first reaction tank (1) and stir to generate a mixed solution of 2-pentyl-4-bromo-2-cyclopentenone. After the reaction is completed, discharge it into the first catalyst recovery tank (2). S2: Add triphenylphosphine solution to the first catalyst recovery tank (2) to generate catalyst precipitate. Discharge the catalyst precipitate at the bottom of the first catalyst recovery tank (2) for recovery. Then perform segmented distillation to distill and cool 1-heptenyne to obtain 2-pentyl-4-bromo-2-cyclopentenone solution, and discharge it into the layered tank (3). S3: Anhydrous methanol is discharged into the layered tank (3). 2-pentyl-4-bromo-2-cyclopentenone dissolves in the anhydrous methanol to form an upper organic mixed phase and a lower toluene phase. The bottom toluene phase is discharged and the remaining organic mixed phase is discharged into the second reaction tank (4). S4: Add an appropriate amount of anhydrous methanol to the second reaction vessel (4), then discharge dimethyl malonate and slowly add sodium methoxide. Perform reflux addition reaction at -5-0℃ and continue stirring. After the reaction is completed, heat to carry out decarboxylation reaction and discharge into the second catalyst recovery vessel (5). Collect methyl 4-bromo-dihydrojasmonic acid by fractional vacuum distillation and discharge sodium methoxide solution from the bottom. S5: The distilled methyl 4-bromo-dihydrojasmonic acid is discharged into the third reaction vessel. After adding toluene and sodium carbonate, a debromination reaction is carried out to generate a methyl jasmonic acid solution with α,β-double bonds. Then, the methyl jasmonic acid solution with α,β-double bonds is purified. S6: Methyl jasmonate with α,β-double bonds is introduced into the fourth reaction vessel, where a Pt / C catalyst and a halogen curing agent are added, and hydrogen gas is introduced to generate cis-dihydrojasmonate methyl ester.
2. The method for synthesizing methyl cis-dihydrojasmonic acid according to claim 1, characterized in that, The gas circulation device includes an air pump, a gas distribution cylinder (14) and multiple gas supply pipes (15). The top of the gas distribution cylinder (14) is provided with a main air inlet pipe, and the bottom is provided with a ring of exhaust branch pipes. The outlet end of the air pump is connected to the main air inlet pipe through a first hose, and each exhaust branch pipe is connected to the bottom end of a gas supply pipe (15) through a second hose. The bottom of the first reaction vessel (1) is provided with a detachable arc-shaped base cover (12). The center of the arc-shaped base cover (12) is provided with a first reaction discharge pipe (121). A ring of gas supply pipe (15) is inserted through the arc-shaped base cover (12) around the first reaction discharge pipe (121). An exhaust head (16) is screwed onto the end of the gas supply pipe inside the arc-shaped base cover (12). The exhaust head (16) has exhaust holes (161) evenly distributed on it. The first reaction vessel (1) is sealed with a first reaction vessel cover (13). The first reaction vessel cover (13) is provided with four first solenoid valve tubes. A mechanically sealed first stirring device (131) is installed in the middle of the first reaction vessel cover (13). The first stirring device (131) is inserted into the first reaction vessel (1). One of the first solenoid valve tubes is used to add 1-heptyne solution dissolved in toluene, and a catalyst discharge branch pipe is connected to the 1-heptyne solution delivery pipe. The second and third first solenoid valve tubes are respectively the inlet pipe and the outlet pipe. The fourth first solenoid valve tube is connected to the inlet end of the gas pump through a third hose.
3. The method for synthesizing methyl cis-dihydrojasmonic acid according to claim 2, characterized in that, A mixture of 1-bromoethylene and carbon monoxide is discharged into the first reaction vessel (1) through the second first solenoid valve tube, and gas is discharged outward through the third first solenoid valve tube to exchange the gas in the first reaction vessel (1). Then, a 1-heptyne solution dissolved in toluene and a cobalt catalyst solution are discharged into the first reaction vessel (1). The solenoid valves in the first and third first solenoid valve tubes are closed. The second first solenoid valve tube continues to pressurize the first reaction vessel (1) so that the gas pressure in the first reaction vessel (1) reaches 2-6 atmospheres. Then, the solenoid valve in the second first solenoid valve tube is closed, and the first reaction vessel (1) is heated to 60-95°C and reacted for 18-24 hours. The gas pump circulates and pumps the gas in the first reaction tank (1) into the gas distribution cylinder (14), and then distributes the gas evenly to the bottom of the first reaction tank (1) through multiple gas supply pipes (15), so that the gas and the reaction liquid are in full contact. The gas pressure inside the first reaction tank (1) is monitored in real time. When the gas pressure is lower than the preset value, the solenoid valve in the second solenoid valve tube is opened, and gas is supplied to the first reaction tank (1) to replenish the gas pressure.
4. The method for synthesizing methyl cis-dihydrojasmonic acid according to claim 2, characterized in that, The first catalyst recovery tank (2) is provided with a sedimentation cylinder (23) at the bottom. The sedimentation cylinder (23) is provided with a discharge pipe (231) near the top. The first catalyst recovery tank (2) is provided with a first recovery tank cover (22) at the top. The first recovery tank cover (22) is provided with four second solenoid valve pipes. The first recovery tank cover (22) is provided with a second stirring device (221) in the middle. The first reaction discharge pipe (121) is connected to the first second solenoid valve pipe. The second second solenoid valve pipe is a distillation pipe. The third second solenoid valve pipe is a feeding pipe. The fourth second solenoid valve pipe is a pressure relief pipe. When the solenoid valve in the fourth second solenoid valve tube is opened, the first reaction tank (1) discharges the reaction solution into the first catalyst recovery tank (2). After the reaction solution is discharged, the first second solenoid valve tube is closed, and the triphenylphosphine solution is discharged into the first catalyst recovery tank (2) from the third second solenoid valve tube. The solenoid valve in the third second solenoid valve tube is closed, and the mixture is stirred at room temperature for 30 minutes. The triphenylphosphine reacts with the cobalt catalyst to generate a catalyst precipitate that combines triphenylphosphine with the cobalt catalyst. The catalyst precipitate settles into the precipitation cylinder (23). The valve at the bottom of the precipitation cylinder (23) is opened to discharge the solution in the precipitation cylinder (23). The solenoid valve at the bottom of the precipitation cylinder (23) is closed, and the first catalyst recovery tank (2) is started to heat slowly. The mixture is distilled under reduced pressure at 3-5℃ / min and heated to 90-95℃. The temperature is maintained for 10-15 minutes to recover toluene and 1-heptayn.
5. The method for synthesizing methyl cis-dihydrojasmonic acid according to claim 4, characterized in that, A 90° T-shaped tee pipe (321) is connected to the discharge pipe at the bottom of the layered tank (3). The top interface of the 90° T-shaped tee pipe (321) is connected to the discharge pipe at the bottom of the layered tank (3). A glass tube (323) is connected to the bottom interface of the 90° T-shaped tee pipe (321). A solenoid valve is installed in the side pipe (322) at the middle position of the 90° T-shaped tee pipe (321). A solenoid valve is installed at the bottom end of the glass tube (323). The top of the layered tank (3) is covered with a layered tank cover (33). Four third solenoid valve pipes are provided on the layered tank cover (33). A third stirring device (34) is installed in the middle position of the layered tank cover (33). The first third solenoid valve pipe is connected to the discharge pipe (231). The second third solenoid valve pipe is an anhydrous methanol addition pipe. The third and fourth third solenoid valve pipes are respectively a gas exchange pipe and a gas venting pipe. After the first catalyst recovery tank (2) has finished discharging the raw material into the stratification tank (3), the solenoid valve in the first third solenoid valve tube is closed, and the second third solenoid valve tube begins to discharge anhydrous methanol into the stratification tank (3) for stirring and dissolution. Stir for 20-30 minutes, and then let it stand to separate into layers. A light transmittance detector is installed next to the glass tube (323). The solenoid valve at the bottom of the glass tube (323) is opened to slowly discharge the toluene phase. When the light transmittance detector detects a significant light transmittance difference in the glass tube (323), the solenoid valve in the glass tube (323) is closed, and the solenoid valve in the upper connecting pipe (322) of the inclined 90° T-shaped three-way pipe (321) is opened to discharge the organic mixed phase into the second reaction vessel (4).
6. The method for synthesizing methyl cis-dihydrojasmonic acid according to claim 5, characterized in that, The top of the second reaction tank (4) is provided with a second reaction tank cover (42), and the second reaction tank cover (42) is provided with five fourth solenoid valve tubes. The middle position of the second reaction tank cover (42) is provided with a fourth stirring device (43). The first fourth solenoid valve tube is a liquid inlet tube, the second fourth solenoid valve tube is a methanol inlet tube, the third fourth solenoid valve tube is a sodium methoxide inlet tube, and the fourth and fifth fourth solenoid valve tubes are respectively a gas exchange inlet tube and a gas outlet tube. After the organic mixed phase is discharged into the second reaction tank (4) by the layered tank (3), the solenoid valve in the first fourth solenoid valve tube is closed, and the second fourth solenoid valve tube adds an appropriate amount of anhydrous methanol into the second reaction tank (4). The temperature in the second reaction tank (4) is 0-5℃. At this time, sodium methoxide is slowly discharged into the second reaction tank (4) through the third fourth solenoid valve tube and continuously stirred and mixed. The stirring reaction is carried out for 2-4 hours. An appropriate amount of anhydrous methanol is added. Then, the temperature of the second reaction tank (4) is adjusted to 60-70℃ and the methanol reflux reaction is carried out for 20-24 hours. After the decarboxylation reaction is completed in the second reaction tank (4), the reaction liquid is discharged into the second catalyst recovery tank (5).
7. The method for synthesizing methyl cis-dihydrojasmonic acid according to claim 6, characterized in that, Each of the second reaction tanks (4) has bottom side pipes (322) of 2-3 layered tanks (3) connected to the liquid inlet end of the second reaction tank (4) through branch pipes. Each of the second catalyst recovery tanks (5) has 4-8 liquid inlet pipes on the tank wall near the top. Each liquid inlet pipe is connected to the discharge pipe at the bottom of a second reaction tank (4).
8. The method for synthesizing methyl cis-dihydrojasmonic acid according to claim 6, characterized in that, The top of the second catalyst recovery tank (5) is covered with a second catalyst recovery tank cover (52). The second catalyst recovery tank cover (52) is provided with four fifth solenoid valve tubes. A fifth stirring device (53) is installed in the middle of the second catalyst recovery tank cover (52). The first fifth solenoid valve tube is a nitrogen inlet tube, the second fifth solenoid valve tube is a methanol evaporation tube, the third fifth solenoid valve tube is a low-boiling impurity evaporation tube, and the fourth fifth solenoid valve tube is a methyl 4-bromo-dihydrojasmonic acid evaporation tube. The second catalyst recovery tank (5) is first heated to 60-80℃ to evaporate methanol, and then vacuum distillation is started; Vacuum distillation steps: The third fifth solenoid valve tube evacuates gas to reduce the pressure of the second catalyst recovery tank. The first fifth solenoid valve tube is filled with a small amount of nitrogen and heated to 80-120°C to distill off residual low-boiling impurities. The solenoid valve in the third fifth solenoid valve tube is closed, and the solenoid valve in the fourth fifth solenoid valve tube is opened to evacuate gas. The temperature is heated to 140-160°C to distill off methyl 4-bromo-dihydrojasmonate. The mixture is then cooled and the sodium methoxide mixture at the bottom of the second catalyst recovery tank (5) is discharged.
9. The method for synthesizing methyl cis-dihydrojasmonic acid according to claim 8, characterized in that, The fourth fifth solenoid valve tube is connected to the liquid inlet of multiple third reaction tanks through a branch pipe. The structure of the third reaction tank is the same as that of the second reaction tank (4). Five sixth solenoid valve tubes are provided on the tank cover at the top of the third reaction tank. The first sixth solenoid valve tube is connected to the branch pipe. The second and third sixth solenoid valve tubes are the gas inlet and gas outlet respectively. The fourth sixth solenoid valve tube is the solvent addition tube. The fifth sixth solenoid valve tube is the sodium carbonate addition tube. Toluene solvent is discharged into the third reaction vessel through the fourth solenoid valve tube to dissolve methyl 4-bromo-dihydrojasmonic acid. Then, an appropriate amount of sodium carbonate is slowly added through the fifth solenoid valve tube to dissolve the methyl 4-bromo-dihydrojasmonic acid. The reaction is stirred and carried out at a temperature of 110-115°C. Toluene is refluxed for 8-12 hours to obtain methyl 4-jasmonic acid product with α,β-double bonds.
10. The method for synthesizing methyl cis-dihydrojasmonic acid according to claim 9, characterized in that, For every two of the third reaction vessels, the product is transferred to a fourth reaction vessel. Nano-sized Pt particles loaded on the surface of powdered activated carbon are added to the fourth reaction vessel, followed by the addition of a halogen curing agent. The mixture is stirred at room temperature for 30 minutes. After purification, the methyl jasmonate product with α,β-double bonds is discharged into the fourth reaction vessel. The fourth reaction vessel is sealed, and the air inside the fourth reaction vessel is replaced with hydrogen 3-5 times. Hydrogen is introduced until the target pressure of 0.5-1 MPa is reached, the temperature is raised to 30-40℃, the stirring rate is controlled at 300-500 r / min, and the reaction is carried out for 4-6 hours.