Preparation method of ethyl linalool
A five-step reaction process using butanone as a raw material addresses the inefficiency of existing ethyl linalool synthesis, achieving high-yield ethyl linalool production suitable for industrial applications.
Patent Information
- Application Number
- CN202311843211.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-29
- Publication Date
- 2024-12-20
AI Technical Summary
The existing method for synthesizing ethyl linalool is inefficient and not suitable for industrial production.
A five-step reaction process involving acetylation, selective hydrogenation, and rehydrogenation using butanone as a raw material, with specific conditions for temperature, pressure, and catalysts to produce ethyl linalool.
The method optimizes the process for economy and environmental protection, producing high-yield ethyl linalool with improved efficiency.
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of fine chemicals, and in particular to a method for preparing ethyl linalool. Background Art
[0002] Ethyl linalool is a must-have spice for preparing rose essence. It is also suitable for the fragrance of lily of the valley, lilac, tuberose, vanilla, acacia, orange blossom, osmanthus, orchid, violet, jasmine, bay leaf, etc. It has a wide range of applications and is not limited by type. It is especially used in soap or hair wax essences, and can also be used in food essences and tobacco essences.
[0003] The ethyl linalool currently available on the market is synthesized according to the following route: methyl ethyl vinyl methanol and isopropenyl methyl ether are condensed and added to form ethyl heptenone, which is then converted into ethyl dehydrolinalool, and finally selectively hydrogenated to obtain ethyl linalool. However, the above method has low efficiency and is not suitable for industrial production. Therefore, a method for preparing ethyl linalool is proposed to address the above problem. Summary of the invention
[0004] The object of the present invention is to provide a method for preparing ethyl linalool to solve the problems raised in the above background technology.
[0005] To achieve the above object, the present invention provides the following technical solutions: A method for preparing ethyl linalool comprises the following steps: Step 1: Put butanone and KOH solution into an autoclave, and press acetylene ammonia into it to carry out acetylation reaction to generate methylpentynol; Step 2: subjecting methylpentynol to a selective hydrogenation reaction with a palladium catalyst to generate methylpentenol; Step 3: Add aluminum isopropoxide and diethyl methyl ester to a three-necked flask and heat to 130-170° C., dropwise add methyl pentenol, and then carry out a heat-insulating reaction to generate ethyl heptenone; Step 4: Ethylheptenone undergoes an acetylation reaction to generate dehydroethyl linalool; Step 5: Dehydrogenated ethyl linalool is then subjected to a selective hydrogenation reaction to generate ethyl linalool.
[0006] Preferably, the feed ratio of butanone to KOH solution in step 1 is 7-9:1.
[0007] Preferably, the pressure of the acetylation reaction in step 1 is 1.0-1.5 MPa.
[0008] Preferably, the pressure of the selective hydrogenation reaction in step 2 is 1.0-1.5 MPa.
[0009] Preferably, the temperature of the selective hydrogenation reaction in step 2 is 50-65°C.
[0010] Preferably, the dropping temperature of methylpentenol in step three is 150-160°C.
[0011] Preferably, the addition time of methylpentenol in step three is 5-6 hours.
[0012] Preferably, in step three, the insulation temperature is 160-170°C.
[0013] Preferably, in step three, the insulation reaction time is 5-6 hours.
[0014] Preferably, the pressure of the acetylation reaction in step 4 is 1.0-1.5 MPa.
[0015] Preferably, the pressure of the hydrogenation reaction in step 5 is 1.0-1.5 MPa.
[0016] Preferably, the temperature of the hydrogenation reaction in step 5 is 50-55°C.
[0017] Compared with the prior art, the invention has the following beneficial effects: using butanone as a raw material, the product is prepared by a five-step reaction method of acetylation, selective hydrogenation, Karl Fischer reaction, reacetylation, and rehydrogenation. The invention optimizes the existing process from the perspectives of economy and environmental protection, and the raw material source is convenient, and a high-content ethyl linalool product is prepared with a high yield. DETAILED DESCRIPTION
[0018] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0019] The present invention provides a technical solution: A method for preparing ethyl linalool comprises the following steps: Step 1: Put butanone and KOH solution into the autoclave at a feed ratio of 6-10:1, and pressurize acetylene ammonia to carry out acetylation reaction to generate methylpentynol; Step 2: subjecting methylpentynol and palladium catalyst to selective hydrogenation reaction at a temperature of 35--80°C and a pressure of 0.5-2.5MPa to generate methylpentenol; Step 3: Add aluminum isopropoxide and diethyl methyl ester to a three-necked flask and heat to 130-170°C, then drop methyl pentenol for 4-8 hours. After the dropwise addition is complete, heat and react for 3-6 hours to generate ethyl heptenone. Step 4: Ethylheptenone undergoes an acetylation reaction to generate dehydroethyl linalool; Step 5: Dehydrogenated ethyl linalool is then subjected to a selective hydrogenation reaction to generate ethyl linalool.
[0020] The preparation method of ethyl linalool recorded in the present invention will be further described below in conjunction with specific cases: Case 1: 144.2 g of butanone and 15 ml of KOH solution were put into a 2L hydrogenation kettle and replaced with nitrogen (0.5 MPa) for 3 times (the remaining acetylene ammonia can be used for replacement 3 times in the experiment to reduce the reaction liquid temperature to below 20°C for convenient reaction), cooled to below 20°C, 520 g of acetylene ammonia solution was pressed in, the pressure was about 1.2-1.5 MPa, reacted for 3 hours (reacted until butanone was below 1%), the acid was adjusted to below 7 with concentrated sulfuric acid, and the unreacted butanone was removed by distillation at 110°C under normal pressure to obtain 186.5 g of methyl pentynol with a yield of 95.05%.
[0021] First, add 1.5g of homemade catalyst to a 500ml high-pressure hydrogenation kettle, then add 186.5g of methylpentynol, 0.2g of auxiliary agent, replace with nitrogen 3 times (0.5MPa), replace with hydrogen 3 times, pressurize with 1MPa hydrogen, heat to 55°C, and add hydrogen pressure to 1.5Mpa. Absorb hydrogen to 1.0 and add to 1.5, and maintain the reaction temperature at 55-65°C. The amount of hydrogen absorbed is about 20Mpa. Filter and recover the catalyst for use, and obtain 186.8g of filtrate, which is 3-methyl-1-pentene-3-ol, with a yield of 98.16%, which is directly used as the raw material for the next step.
[0022] Take a 3-liter three-necked flask and add 12g of aluminum isopropoxide, 19.5g of diethyl methyl ester and 0.1g of triethanolamine. Heat to 155-160°C, then add 186.8g of methylpentenol and 249.2g of diethyl methyl ester obtained in the previous step dropwise (addition is completed in 5 hours). After the addition is completed, heat to 165-170°C and keep the temperature for 5 hours. Distill at 100-110°C to obtain 236.5g of ethyl heptenone with a yield of 90.44%.
[0023] 236.5g of ethyl heptenone and 16ml of KOH solution were put into a hydrogenation kettle and replaced with nitrogen (0.5MPa) 3 times (the experiment can use the remaining acetylene ammonia to replace 3 times, which can reduce the temperature of the reaction liquid to below 20℃ for convenient reaction), cooled to below 20℃, pressed into 700g of acetylene ammonia, the pressure was about 1.2-1.5MPa, reacted for 3 hours (reacted until ethyl heptenone was below 1%), pressed out the reaction liquid, deaminated in a 70℃ water bath for 3 hours, washed with water five times, added 100g of water each time, mechanically stirred for half an hour and allowed to stand for stratification. (Washed with water until the pH of the reaction liquid was between 7-8), vacuum removed water at 55℃, distilled at 85-90℃ to obtain 265.3g of 98+ dehydroethyl linalool, with a yield of 94.63%.
[0024] First, add 1.5g of catalyst to the hydrogenation kettle, then add 265.3g of dehydrogenated ethyl linalool, 0.2g of auxiliary agent, replace with nitrogen 3 times (0.5MPa), replace with hydrogen 3 times (0.5MPa), pressurize with 1MPa of hydrogen, heat to 50°C, and add hydrogen pressure to 1.5Mpa. Absorb hydrogen to 1.2 and add to 1.5, and maintain the reaction temperature at 50-55°C. The amount of hydrogen absorbed is about 13Mpa. Distill at 90-95°C to obtain 255.1g of ethyl linalool with a yield of 95.02% or more of 98%.
[0025] Combining the above reactions, the total yield was 75.87%.
[0026] Case 2: 144.2 g of butanone and 20 ml of KOH solution were put into a 2L hydrogenation kettle and replaced with nitrogen (0.5 MPa) for 3 times (the remaining acetylene ammonia can be used for replacement 3 times in the experiment to reduce the reaction liquid temperature to below 20°C for convenient reaction), cooled to below 20°C, 530 g of acetylene ammonia solution was pressed in, the pressure was about 1.0-1.2 MPa, reacted for 3 hours (reacted until butanone was below 1%), the acid was adjusted to below 7 with concentrated sulfuric acid, and the unreacted butanone was removed by distillation at 110°C under normal pressure to obtain 185.8 g of methyl pentynol with a yield of 94.69%.
[0027] First, add 1.5g of self-made catalyst to a 500ml high-pressure hydrogenation kettle, then add 185.8g of methylpentynol, 0.2g of auxiliary agent, replace with nitrogen 3 times (0.5MPa), replace with hydrogen 3 times, pressurize with 1MPa hydrogen, heat to 50°C, and add hydrogen pressure to 2Mpa. Absorb hydrogen to 1.0 and add to 2.0, and maintain the reaction temperature at 50-55°C. The amount of hydrogen absorbed is about 20Mpa. Filter and recover the catalyst for application, and obtain 186.2g of filtrate, which is 3-methyl-1-pentene-3-ol, with a yield of 98.21%, which is directly used as the raw material for the next step.
[0028] Take a 3-liter three-necked flask and add 12g of aluminum isopropoxide, 19.5g of diethyl methyl ester and 0.1g of triethanolamine. Heat to 150-155°C, then add 186.2g of methylpentenol and 249.2g of diethyl methyl ester obtained in the previous step dropwise (addition is completed in 6 hours). After the addition is completed, heat to 160-165°C and keep the temperature for 6 hours. Distill at 100-110°C to obtain 235.5g of ethyl heptenone with a yield of 90.35%.
[0029] 235.5g of ethyl heptenone and 16ml of KOH solution were put into a hydrogenation kettle and replaced with nitrogen (0.5MPa) 3 times (the experiment can be replaced with the remaining acetylene ammonia 3 times, which can reduce the temperature of the reaction liquid to below 20℃ for convenient reaction), cooled to below 20℃, pressed into 700g of acetylene ammonia, the pressure was about 1.0-1.2MPa, reacted for 3 hours (reacted until ethyl heptenone was below 1%), pressed out the reaction liquid and deaminated in a 60℃ water bath for 3 hours, washed with water five times, added 100g of water each time, mechanically stirred for half an hour and allowed to stand for stratification. (Washed with water until the pH of the reaction liquid was between 7-8), vacuum removed water at 55℃, distilled at 85-90℃ to obtain 263.8g of 98+ dehydroethyl linalool, with a yield of 94.49%.
[0030] First, add 1.5g of catalyst to the hydrogenation kettle, then add 263.8g of dehydrogenated ethyl linalool, 0.2g of auxiliary agent, replace with nitrogen 3 times (0.5MPa), replace with hydrogen 3 times (0.5MPa), pressurize with 1MPa of hydrogen, heat to 50°C, and add hydrogen pressure to 1.5Mpa. Absorb hydrogen to 1.0 and add to 1.5, and maintain the reaction temperature at 50-55°C. The amount of hydrogen absorbed is about 13Mpa. Distill at 90-95°C to obtain 253.1g of ethyl linalool with a yield of 94.81% or more of 98%.
[0031] Combining the above reactions, the total yield was 75.27%.
[0032] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A method for preparing ethyl linalool, characterized in that: The steps include: Step 1: Put butanone and KOH solution into an autoclave, and press acetylene ammonia into it to carry out acetylation reaction to generate methylpentynol; Step 2: subjecting methylpentynol to a selective hydrogenation reaction with a palladium catalyst to generate methylpentenol; Step 3: Add aluminum isopropoxide and diethyl methyl ester to a three-necked flask and heat to 130-170° C., dropwise add methyl pentenol, and then carry out a heat-insulating reaction to generate ethyl heptenone; Step 4: Ethylheptenone undergoes an acetylation reaction to generate dehydroethyl linalool; Step 5: Dehydrogenated ethyl linalool is then subjected to a selective hydrogenation reaction to generate ethyl linalool.
2. A method for preparing ethyl linalool according to claim 1, characterized in that: In step 1, the feed ratio of butanone to KOH solution is 6-10:
1.
3. A method for preparing ethyl linalool according to claim 1, characterized in that: The pressure of the acetylation reaction in step 1 is 0.5-1.5 MPa.
4. A method for preparing ethyl linalool according to claim 1, characterized in that: In step 2, the selective hydrogenation reaction is carried out at a temperature of 35-80°C.
5. A method for preparing ethyl linalool according to claim 1, characterized in that: The pressure of the selective hydrogenation in step 2 is 0.5-2.5 MPa.
6. A method for preparing ethyl linalool according to claim 1, characterized in that: The dropping temperature of methylpentenol in step 3 is 130-170°C.
7. A method for preparing ethyl linalool according to claim 1, characterized in that: The dropping time of methylpentenol in step 3 is 4-8h.
8. A method for preparing ethyl linalool according to claim 1, characterized in that: In step 3, the insulation reaction temperature of methylpentenol is 150-180° C., and the insulation reaction time is 3-7 hours.
9. A method for preparing ethyl linalool according to claim 1, characterized in that: The pressure of the acetylation reaction in step 4 is 0.5-2.0 MPa.
10. The method for preparing ethyl linalool according to claim 1, wherein: In step 5, the pressure of the selective hydrogenation is 0.5-2.0 MPa, and the temperature of the selective hydrogenation reaction is 40-70°C.