Method for improving quality of synthetic perfume by molecular distillation and rectification coupling separation technology

Abstract

The invention discloses a method for improving the quality of a synthetic spice by a molecular distillation and rectification coupling separation technology, and belongs to the technical field of separation and purification of spices and essences. Molecular distillation serves as a pretreatment step, most impurities are removed firstly, the load of a follow-up rectifying tower is reduced, and the rectifying process is more stable and efficient; the two are coupled to form complementary advantages, and the bottleneck of separating complex systems such as azeotrope and isomer in a traditional method is broken through; low-boiling-point impurities and high-boiling-point heavy components in the spice crude product can be efficiently removed, and the purity and the additional value of the product are improved; the method is a physical separation process, no chemical solvent needs to be added in the whole process, the problem of solvent residue is fundamentally avoided, emission of three wastes is reduced, and safety standards of food and medicine industries are met; and the kettle residual liquid after rectification can be recycled and used for the next batch of production, so that the material loss is reduced, the full utilization of the raw materials is realized, and good economical efficiency is achieved.

Description

Technical Field

[0001] This invention belongs to the field of fragrance and flavor separation and purification technology, specifically, it relates to a method for improving the quality of synthetic fragrances using a combination of molecular distillation and rectification separation technology. Background Technology

[0002] The synthetic fragrance industry is facing increasingly stringent quality requirements, particularly in the pharmaceutical, cosmetic, and food sectors, where high purity, preservation of natural aromas, and protection of heat-sensitive components are essential. However, in the production of synthetic fragrances, raw materials often contain multiple components, only some of which possess the desired aroma properties. To improve the quality of synthetic fragrances, these aroma-possessing components need to be effectively extracted and purified. Traditional separation techniques, such as solvent extraction and steam distillation, suffer from solvent residues and high-temperature thermal decomposition, leading to loss of aroma components or impurities. For example, in the extraction of jasmine essential oil, traditional methods may damage heat-sensitive components such as esters, reducing aroma purity. Furthermore, the low separation efficiency of complex mixtures (such as azeotropes and isomers) has become a key bottleneck restricting the improvement of fragrance quality.

[0003] Molecular distillation (MD), also known as short-path distillation, is a continuous distillation process performed under high vacuum conditions. Its principle is based on the differences in the mean free path of escaped molecules of different substances, as well as their volatility, to achieve the separation of substances. Molecular distillation technology is characterized by high efficiency and high precision in separation and purification, and is particularly suitable for the separation of high-boiling-point, heat-sensitive, easily oxidized, or easily polymerized substances.

[0004] Distillation technology, as a core technology in chemical separation, achieves efficient purification by utilizing the differences in boiling points of components. Its core process includes heating and vaporization, mass transfer within the column, and reflux condensation, and it is widely used in petroleum, pharmaceutical, and new energy fields. It is used to separate multi-component mixtures, achieving efficient separation and improving product purity. Its core principle is based on the differences in volatility of components; partial vaporization of the liquid phase is achieved through heating, and separation is realized through mass and heat transfer processes during the contact between the gas and liquid phases.

[0005] This invention combines molecular distillation and rectification techniques. On the one hand, molecular distillation removes low-boiling and heavy components, fundamentally improving aroma quality. On the other hand, it couples efficient rectification to increase content while maintaining aroma quality, thus overcoming the shortcomings of traditional separation technologies and meeting the market demand for high-quality, high-purity products. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for improving the quality of synthetic fragrances using a combination of molecular distillation and rectification separation technology.

[0007] The objective of this invention can be achieved through the following technical solutions: A method for improving the quality of synthetic fragrances using a coupled molecular distillation and rectification separation technique includes the following steps: A1. Put the crude spice into the storage tank of the molecular distillation apparatus, close the vent valve, turn on the rotary vane pump and diffusion pump, gradually draw a vacuum, start the scraper to ensure uniform distribution of the liquid film, turn on the oil bath heating, and during the heating process, condense and separate the low boiling point impurities through the condenser and collect them as light components. The high boiling point heavy component impurities are deposited on the inner wall of the distillation apparatus and discharged periodically. The vapor of the target component is condensed through a short path and collected as a high content intermediate product. The light components, heavy components and high content intermediate products are collected separately. A2. Transfer the high-content intermediate product to the glass vessel of the distillation column, turn on the oil pump to gradually create a vacuum, and then turn on the heating device. When the vessel temperature rises to 100℃, slowly turn on the heating cable of the column body to continue heating. The temperature inside the vessel continues to rise until it reaches 140-170℃. When condensate begins to appear at the top of the column, the total reflux stage begins. Maintain total reflux for 2 hours to achieve gas-liquid balance in the column. After that, adjust the top reflux ratio to carry out initial distillation. After initial distillation, take a sample from the column every 2 hours. When no low-boiling impurities are detected in the sample and the content of the target component is higher than 98%, adjust the reflux ratio to 1 / 25 and start collecting the finished product. Adjust the collection rate and maintain a uniform collection rate until 3-8% of the total feed remains in the vessel. Stop discharging to obtain the finished product.

[0008] As a further technical solution, in step A1, a vacuum is drawn until the pressure is 160-300 Pa.

[0009] As a further technical solution, the rotation speed of the scraper in step A1 is 400-500 rpm.

[0010] As a further technical solution, the oil bath heating temperature in step A1 is 70-90℃.

[0011] As a further technical solution, the condensation temperature in step A1 is -10~10℃.

[0012] As a further technical solution, during the collection process in step A1, gas chromatography is used to monitor the purity of the intermediate product in real time to ensure that the content of the heavy components is not less than 90%.

[0013] As a further technical solution, in step A2, a vacuum is drawn until the pressure is 160-300 Pa.

[0014] As a further technical solution, the top-mining reflux ratio in step A2 is 1 / 10-1 / 20.

[0015] As a further technical solution, the initial distillation time in step A2 is 3-5 hours.

[0016] As a further technical solution, the extraction rate in step A2 is 350-550 g / h.

[0017] This invention utilizes molecular distillation to first remove low-boiling-point impurities and high-boiling-point heavy components from the raw materials, obtaining a high-content intermediate product containing the target aroma components. Then, rectification distillation is used to further separate and purify this high-content intermediate product, yielding a synthetic fragrance with high purity and strong aroma characteristics. This combined technique not only improves the quality of the synthetic fragrance but also achieves full utilization and efficient separation of the raw materials. Furthermore, since both molecular distillation and rectification distillation are performed under relatively mild conditions, the quality of heat-sensitive aroma components is well preserved, avoiding aroma loss or deterioration caused by high temperatures or prolonged heating.

[0018] The beneficial effects of this invention are: 1. The method of the present invention can efficiently remove low-boiling-point impurities and high-boiling-point heavy components from crude fragrance products, breaking through the traditional separation bottleneck and improving product purity and added value. 2. The entire separation process is carried out under high vacuum and relatively mild temperature, which greatly reduces the risk of fragrance components decomposing, oxidizing or deteriorating due to high temperature heating, and effectively protects the natural quality of heat-sensitive aroma substances. 3. This method is a physical separation process that does not require the addition of any chemical solvents, thus fundamentally avoiding solvent residue problems, reducing the discharge of waste gas, wastewater, and solid waste, and meeting the safety standards of the food and pharmaceutical industries. 4. Molecular distillation, as a pretreatment step, removes both light and heavy components to ensure aroma quality and reduces the load on subsequent single distillation columns, making the distillation process more stable and efficient. The coupling of the two forms a complementary advantage, breaking through the bottleneck of traditional methods for separating complex systems such as azeotropes and isomers. 5. The residue after distillation can be recovered and reused in the next batch of production, which reduces material loss, realizes full utilization of raw materials, and has good economic benefits; In summary, the method of this invention, through the coupling of molecular distillation and rectification techniques, successfully achieves efficient, high-precision, and mild purification of synthetic fragrances, providing a reliable separation technology with broad application prospects for the production of high-purity, high-quality fragrance products. Attached Figure Description

[0019] The invention will now be further described with reference to the accompanying drawings.

[0020] Figure 1This is a data analysis chart showing the detection of the peach aldehyde product obtained in Example 1 in this embodiment of the invention. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0022] In Embodiments 1, 2, and 3 of this invention, the crude fragrance product is crude peach aldehyde.

[0023] Example 1 A method for improving the quality of synthetic fragrances using a coupled molecular distillation and rectification separation technique includes the following steps: A1. Check the airtightness of the vacuum pump and condenser, then put 2000g of crude peach aldehyde into the storage tank of the molecular distillation apparatus, close the vent valve, turn on the rotary vane pump and diffusion pump, and gradually evacuate to a pressure of 160Pa. Start the scraper and adjust the speed to 500rpm to ensure uniform distribution of the liquid film. Turn on the oil bath heating to raise the temperature to 85℃. During the heating process, condense through the condenser at a temperature of 0℃ to separate low-boiling-point impurities and collect them as light components. High-boiling-point heavy component impurities are deposited on the inner wall at the bottom of the distillation apparatus and discharged periodically. The vapor of the target component is condensed after short-path condensation and used as a high-content intermediate. Collect the light components, heavy components and high-content intermediates, and use gas chromatography to monitor the purity of the intermediates in real time to ensure that the content of heavy components is not less than 90%. 1737g of intermediate product is obtained. A2. Transfer 1737g of intermediate product to a 2L glass vessel in a distillation column. Start the oil pump and gradually evacuate to a pressure of 160Pa. Then turn on the heating device. When the vessel temperature reaches 100℃, slowly turn on the column heating cable. The temperature inside the vessel continues to rise until it reaches 150℃. When condensate begins to appear at the top of the column, it enters the total reflux stage. Maintain total reflux for 2 hours to achieve gas-liquid equilibrium within the column. Afterward, adjust the top reflux ratio to 1 / 15 for initial distillation. After 3 hours of initial distillation, take samples from the column every 2 hours. When octanol is undetectable by GC and the peach aldehyde content is higher than 98%, adjust the reflux ratio to 1 / 25 and begin collecting the finished product. Adjust the collection rate to 450g / h and maintain a uniform collection rate until 5% of the total feed remains in the vessel. Stop discharging to obtain the peach aldehyde product. Use gas chromatography to perform qualitative and quantitative analysis on the product. The resulting chromatogram is shown below. Figure 1 As shown, the content of peach aldehyde in the finished product was 98.76%.

[0024] Example 2 A method for improving the quality of synthetic fragrances using a coupled molecular distillation and rectification separation technique includes the following steps: A1. Check the airtightness of the vacuum pump and condenser, then put 2000g of crude peach aldehyde into the storage tank of the molecular distillation apparatus, close the vent valve, turn on the rotary vane pump and diffusion pump, and gradually evacuate to a pressure of 160Pa. Start the scraper and adjust the speed to 400rpm to ensure uniform distribution of the liquid film. Turn on the oil bath heating to raise the temperature to 70℃. During the heating process, condense through the condenser at a temperature of -10℃ to separate low-boiling-point impurities and collect them as light components. High-boiling-point heavy component impurities are deposited on the inner wall of the distillation apparatus and discharged periodically. The vapor of the target component is condensed after short-path condensation and used as a high-content intermediate. Collect the light components, heavy components and high-content intermediates, and use gas chromatography to monitor the purity of the intermediates in real time to ensure that the content of heavy components is not less than 90%. 1695g of intermediate product is obtained. A2. Transfer 1695g of intermediate product to a 2L glass vessel in a distillation column. Start the oil pump and gradually evacuate to a pressure of 160Pa. Then turn on the heating device. When the vessel temperature reaches 100℃, slowly turn on the heating cable in the column body. The temperature inside the vessel continues to rise until it reaches 140℃. When condensate begins to appear at the top of the column, the total reflux stage begins. Maintain total reflux for 2 hours to achieve gas-liquid balance in the column. Then adjust the top reflux ratio to 1 / 10 for initial distillation. After 3 hours of initial distillation, take samples from the column every 2 hours. When no octanol (GC) is detected in the sample and the peach aldehyde content is higher than 98%, adjust the reflux ratio to 1 / 25 and start collecting the finished product. Adjust the collection rate to 350g / h and maintain a uniform collection rate until 3% of the total feed remains in the vessel. Stop discharging to obtain the peach aldehyde product. The peach aldehyde content of the finished product is 97.89%.

[0025] Example 3 A method for improving the quality of synthetic fragrances using a coupled molecular distillation and rectification separation technique includes the following steps: A1. Check the airtightness of the vacuum pump and condenser, then put 2000g of crude peach aldehyde into the storage tank of the molecular distillation apparatus, close the vent valve, turn on the rotary vane pump and diffusion pump, and gradually evacuate to a pressure of 300Pa. Start the scraper and adjust the speed to 500rpm to ensure uniform distribution of the liquid film. Turn on the oil bath heating to raise the temperature to 90℃. During the heating process, condense through the condenser at a temperature of 10℃ to separate low-boiling-point impurities and collect them as light components. High-boiling-point heavy component impurities are deposited on the inner wall of the distillation apparatus and discharged periodically. The vapor of the target component is condensed after short-path condensation and used as a high-content intermediate. Collect the light components, heavy components and high-content intermediates, and use gas chromatography to monitor the purity of the intermediates in real time to ensure that the content of heavy components is not less than 90%. 1856g of intermediate product is obtained. A2. Transfer 1856g of intermediate product to a 2L glass vessel in a distillation column. Start the oil pump and gradually evacuate to a pressure of 300Pa. Then turn on the heating device. When the vessel temperature reaches 100℃, slowly turn on the heating cable in the column body. The temperature inside the vessel continues to rise until it reaches 170℃. When condensate begins to appear at the top of the column, the total reflux stage begins. Maintain total reflux for 2 hours to achieve gas-liquid balance in the column. Then adjust the top reflux ratio to 1 / 20 for initial distillation. After 5 hours of initial distillation, take samples from the column every 2 hours. When no octanol (GC) is detected in the sample and the peach aldehyde content is higher than 98%, adjust the reflux ratio to 1 / 25 and start collecting the finished product. Adjust the collection rate to 550g / h and maintain a uniform collection rate until 8% of the total feed remains in the vessel. Stop discharging to obtain the peach aldehyde product. The peach aldehyde content of the finished product is 97.92%.

[0026] Comparative Example 1 Use crude peach aldehyde that has not been treated by the method of this invention (or has only been treated by conventional distillation).

[0027] The aroma quality of Examples 1, 2, 3 and Comparative Example 1 was tested using a sensory evaluation method. The determination method is as follows: Ten sensory evaluators (meeting the requirements of GB / T 14454.2-2008 "Fragrance Aroma Evaluation Method") conducted sensory evaluations on the samples (scoring on a scale of 1-5 points, with higher scores for samples that are closer to the evaluation criteria). The evaluation results are shown in Table 1: Table 1 Evaluation indicators Example 1 Example 2 Example 3 Comparative Example 1 Aroma purity (the overall aroma is pure and singular, without any obvious off-flavors). 5 5 5 3 The initial scent is pleasant and mild (without any unpleasant irritation or chemical odor when first smelled). 5 5 5 2 Oily / waxy smell (no residual unpleasant oily or waxy odor) 5 5 5 2 As shown in Table 1, the method of the present invention, through the coupling of molecular distillation and rectification technology, produces fragrances with high aroma purity, no obvious off-flavors in the top notes, and weak oily aroma, which meets the fragrance quality standards in the food, cosmetics, or pharmaceutical fields.

[0028] In the description of this specification, the 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 present invention. In this specification, the 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.

[0029] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A method for improving the quality of synthetic fragrances using a coupled molecular distillation and rectification separation technique, characterized in that, Includes the following steps: A1. The crude spice product is put into the storage tank of the molecular distillation apparatus, and the vacuum is gradually drawn. The scraper is started and the oil bath heating is turned on. During the heating process, the low boiling point impurities are separated by condenser and collected as light components. The high boiling point heavy component impurities are deposited on the inner wall of the distillation apparatus and discharged periodically. The vapor of the target component is condensed after short-path condensation and collected as high content intermediate products. The light components, heavy components and high content intermediate products are collected separately. A2. Transfer the high-content intermediate product to the glass vessel of the distillation column, gradually evacuate the vacuum, and then turn on the heating device. When the vessel temperature rises to 100℃, turn on the column heating cable to continue heating the vessel. The temperature inside the vessel continues to rise until it reaches 140-170℃. When condensate begins to appear at the top of the column, the total reflux stage begins. Maintain total reflux for 2 hours, then adjust the top reflux ratio for initial distillation. After initial distillation, take a sample from the column every 2 hours. When no low-boiling impurities are detected in the sample and the content of the target component is higher than 98%, adjust the reflux ratio to 1 / 25 and start collecting the finished product. Adjust the collection rate and collect the product until 3-8% of the total feed remains in the vessel. Stop discharging to obtain the finished product.

2. The method for improving the quality of synthetic fragrances using a coupled molecular distillation and rectification separation technology according to claim 1, characterized in that, In step A1, a vacuum is drawn until the pressure is 160-300 Pa.

3. The method for improving the quality of synthetic fragrances using a coupled molecular distillation and rectification separation technology according to claim 1, characterized in that, In step A1, the rotation speed of the scraper is 400-500 rpm.

4. The method for improving the quality of synthetic fragrances using a coupled molecular distillation and rectification separation technology according to claim 1, characterized in that, The oil bath heating temperature in step A1 is 70-90℃.

5. The method for improving the quality of synthetic fragrances using a coupled molecular distillation and rectification separation technology according to claim 1, characterized in that, The condensation temperature in step A1 is -10~10℃.

6. The method for improving the quality of synthetic fragrances using a coupled molecular distillation and rectification separation technology according to claim 1, characterized in that, In step A2, a vacuum is drawn until the pressure is 160-300 Pa.

7. The method for improving the quality of synthetic fragrances using a coupled molecular distillation and rectification separation technology according to claim 1, characterized in that, In step A2, the top-feed reflux ratio is 1 / 10-1 / 20.

8. The method for improving the quality of synthetic fragrances using a coupled molecular distillation and rectification separation technology according to claim 1, characterized in that, The initial distillation time in step A2 is 3-5 hours.

9. The method for improving the quality of synthetic fragrances using a coupled molecular distillation and rectification separation technology according to claim 1, characterized in that, The extraction rate in step A2 is 350-550 g / h.

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