Beta-ionone and a method for its preparation

Abstract

The application provides a continuous preparation method of beta-ionone. By introducing steam into a desolventizing tower, the content of impure ketone can be effectively controlled, the operation flexibility of the whole process can be improved, and the purity requirement of raw material pseudoionone is reduced.

Description

Technical Field

[0001] This invention belongs to the technical field of β-ionone preparation, specifically relating to a method for preparing β-ionone with controllable heteroketone content. Background Technology

[0002] β-ionone [4-(2,6,6-trimethyl-1-cyclohexenyl)-3-buten-2-one, β-ionone] has the molecular formula C13H20O and is a colorless to pale yellow transparent liquid. It is a very important pharmaceutical intermediate and a crucial raw material for the synthesis of vitamin A, β-carotene, carotenoids, retinoic acid, etc. The synthetic route of β-ionone involves the cyclization of pseudoionone under acid catalysis. The reaction equation is as follows:

[0003] (1)

[0004] ψ-ionone [dimethyl-3,5,9-undecanetrien-2-one, ψ-ionone] has the molecular formula C13H20O. It is a pale yellow to yellow oily liquid at room temperature. It is mainly used to synthesize ionone fragrances, vitamins A and E, and β-carotene. It is widely used in the fields of fragrances, pharmaceuticals, and food additives.

[0005] The most commonly used industrial synthesis route for pseudoionones involves the Aldol condensation of citral and acetone in the presence of a base catalyst. The reaction equation is as follows:

[0006] (2)

[0007] In addition to the main reaction mentioned above, there are also side reactions involving the self-condensation of acetone to produce diacetone alcohol and triacetone diol, as well as the side reaction involving the condensation of acetone and pseudoionone to produce a class of substances (substance I) with the molecular formula C16H24O. The reaction equations are as follows:

[0008] (3)

[0009] (4)

[0010] (5)

[0011] Substance I includes and And its cis, trans and optical isomers.

[0012] In the preparation of pseudoionone, acetone is both a reactant and a solvent. After the reaction, the crude pseudoionone product, after acetone removal, still contains impurities such as diacetone alcohol, triacetone diol, and substance I, which require further distillation to remove before obtaining the final pseudoionone product. However, current processes for preparing β-ionone generally do not use the crude pseudoionone product directly; instead, they use the finished pseudoionone product as a raw material.

[0013] Currently, there are numerous reports on the preparation of β-ionone products, such as patents CN1348949A, CN1109462A, and CN1508113A, but there is little disclosure regarding how to prepare β-ionone with low heteroketone content. However, market demands for β-ionone products are becoming increasingly stringent.

[0014] Therefore, there is a need to develop a method for preparing β-ionone with controllable content of heteroketones to meet the application needs of market customers. Summary of the Invention

[0015] The purpose of this invention is to provide a β-ionone with low heteroketone content to meet the application needs of market customers for β-ionone products.

[0016] Another object of the present invention is to provide a method for preparing β-ionone with low heteroketone content.

[0017] To achieve the above-mentioned objectives, the technical solution of the present invention is as follows:

[0018] A β-ionone product, wherein the content of impurities in the β-ionone product is ≤10ppm;

[0019] The aforementioned ketones include the sum of substance II, acetone, diacetone alcohol, and triacetone diol;

[0020] Substance II includes , , , , , And their cis, trans, and optical isomers.

[0021] Preferably, the purity of the β-ionone is 97% or higher, more preferably 98% or higher.

[0022] The β-ionone with low heteroketone content described above has an aroma that meets market requirements and stable color.

[0023] This invention provides a method for preparing β-ionone with low heteroketone content, comprising the following steps:

[0024] (1) The pseudo-ionone raw material and solvent are mixed to prepare a pseudo-ionone solution;

[0025] (2) The pseudo-ionone solution and sulfuric acid were continuously introduced into a microchannel reactor to carry out the cyclization reaction;

[0026] (3) The material from the microchannel reactor and the quenching water are continuously fed into the quenching vessel to quench the reaction output;

[0027] (4) The material discharged from the quenching kettle is continuously collected and enters the phase separator I for phase separation operation to obtain oil phase I and water phase;

[0028] (5) The oil phase I and the deacidifying agent are continuously introduced into the deacidification kettle and stirred to mix for neutralization and deacidification;

[0029] (6) The material discharged from the deacidification kettle is continuously fed into phase separator II for phase separation operation to obtain oil phase II and deacidification residue phase;

[0030] (7) Oil phase II and vapor are each continuously fed into the desolventizing tower for desolventizing operation;

[0031] (8) The solvent removal tower bottom is continuously collected and enters the scraped evaporator for tar removal operation. The top distillate is the product β-ionone.

[0032] In some preferred embodiments, in step (1), the mass ratio of solvent to pseudoionone raw material is 2~20, preferably 3~10;

[0033] The solvent is one or more of benzene compounds, chloroalkanes, and alkanes, preferably one or more of toluene, dichloroethane, dichloromethane, n-heptane, and n-hexane.

[0034] In some preferred embodiments, in step (2), the microchannel reactor has a low-temperature section and a high-temperature section. The pseudo-ionone solution and sulfuric acid first enter the low-temperature section to react, and the material coming out of the low-temperature section flows into the high-temperature section to continue the reaction. The reaction temperatures of the material in the low-temperature section and the high-temperature section are -30~10℃ and 20~50℃, respectively, and the residence times of the material in the low-temperature section and the high-temperature section are 1~20s and 10~40s, respectively.

[0035] The sulfuric acid concentration is 85wt%~98wt%; the mass flow ratio of sulfuric acid to pseudoionone raw material is 1~7.

[0036] In some preferred embodiments, the quenching temperature of the quenching vessel in step (3) is 5~50℃, the quenching residence time is 10~120min, and the mass flow ratio of the quenching water introduced into the quenching vessel to the feed sulfuric acid entering the microreactor is 5~1.

[0037] In some preferred embodiments, the phase separation temperature of phase separator I in step (4) is 5~50℃ and the phase separation dwell time is 10~120min.

[0038] In some preferred embodiments, the deacidifying agent in step (5) is an inorganic weak base, preferably an aqueous solution of potassium bicarbonate, potassium carbonate, sodium bicarbonate and sodium carbonate with a concentration of 0.5wt% to 10wt%.

[0039] The neutralization temperature of the deacidification kettle is 5~50℃, and the neutralization residence time is 10~120min;

[0040] The mass flow ratio of the deacidifying agent to the pseudoionone raw material is 1:(0.5~18).

[0041] In some preferred embodiments, the phase separation temperature of phase separator II in step (6) is 5~50℃ and the phase separation dwell time is 10~120min.

[0042] In some preferred embodiments, in step (7), the mass flow ratio of the desolventizing steam to the pseudoionone raw material is 1:(0.5~17);

[0043] The theoretical number of trays in the solvent removal column is 18~30. The feed positions of the oil phase II stream and the vapor stream entering the solvent removal column are one of the 8th to 14th trays and one of the 13th to 25th trays, respectively. The reflux ratio is 0.5~10, the column bottom temperature is 120~150℃, the column top pressure is 2.9~24.5kPaA, and the column bottom pressure is 6~30kPaA.

[0044] If crude pseudoionone containing a substance with the molecular formula C16H24O (substance I) is used as the starting material for the cyclization reaction, then substance I in the crude pseudoionone will also participate in the reaction to generate a cyclic substance (substance II). The reaction equation is as follows:

[0045] (6)

[0046] When the material flows to the subsequent distillation and separation operation, the diacetone alcohol and triacetone diol brought from the crude pseudoionone will partially decompose upon heating to produce acetone. At the same time, the newly produced acetone will undergo a condensation reaction with ionone to generate a class of substances with cyclic structures (substance II). The reaction equation is as follows:

[0047] (7)

[0048] Diacetone alcohol, triacetone diol, and substance II are continuously heated during distillation, and all of them will partially react to generate acetone, which will also lead to an increase in the content of impurities in the β-ionone product.

[0049] In traditional production processes, the preparation of pseudoionone involves separating and removing diacetone alcohol, triacetone diol, and substance I as much as possible. The cyclization reaction uses the resulting pseudoionone product as a raw material to prepare β-ionone. However, if the pseudoionone raw material for the cyclization reaction contains diacetone alcohol, triacetone diol, and substance I, it is inevitable that impurities will be introduced into the β-ionone product. If these substances are introduced during the β-ionone preparation process, obtaining a low-impurity β-ionone product using traditional distillation becomes difficult, complicates the distillation process, and increases separation energy consumption and costs.

[0050] The method for preparing β-ionone provided by this invention cleverly introduces steam into the solvent removal process in step (7). This not only serves as a stripping agent to improve the solvent removal effect, but also has a good removal effect on diacetone alcohol, triacetone diol, and substance II. After the steam is introduced, the concentration of H2O increases, which can promote the reaction equation (7) to the left. Substance II will be converted into ionone and acetone. At the same time, the steam has a stripping effect on the generated acetone, which can be separated out in time. The continuous separation of acetone will also promote the reaction equation (7) to the left. Diacetone alcohol and triacetone diol will decompose into acetone when heated in the solvent removal tower. The introduced steam can strip and separate acetone, so that the acetone generated by the decomposition of diacetone alcohol and triacetone diol can be stripped out in time, and the reaction equations (3) and (4) will continue to move to the left. Thus, simply introducing a stream of steam into the desolventizing tower is sufficient to eliminate acetone, diacetone alcohol, triacetone diol, and substance II from the system, without requiring additional separation equipment. The method provided by this invention reduces the requirements for pseudo-ionone, the raw material for the cyclization reaction. Even if the raw material contains diacetone alcohol, triacetone diol, and substance I, these substances can be removed and the content of impurities effectively controlled during the preparation of β-ionone.

[0051] Therefore, in this invention, the pseudo-ionone raw material may contain less than 25 wt% of diacetone alcohol, triacetone diol and substance I, and the purity of the pseudo-ionone raw material is above 70%, preferably above 75%.

[0052] The beneficial effects of this invention are as follows:

[0053] (1) The present invention provides a β-ionone with low content of heteroketones, which has aroma that meets market requirements and stable color.

[0054] (2) By introducing steam into the desolventizing tower, the present invention can not only effectively control the content of impurities, but also improve the overall operational flexibility of the process and reduce the purity requirements of the raw material pseudoionone. Detailed Implementation

[0055] To facilitate understanding of the present invention, the following description, in conjunction with embodiments, will further illustrate the invention. It should be understood that the following embodiments are merely for a better understanding of the invention and do not imply that the invention is limited to these embodiments.

[0056] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The term "and / or" may be used herein to include any and all combinations of one or more of the associated listed items.

[0057] Main raw material sources

[0058] Pseudoionone: Wanhua Chemical Group Nutrition Technology Co., Ltd.;

[0059] Sulfuric acid, dichloroethane, dichloromethane, n-hexane, n-heptane, toluene, sodium bicarbonate, sodium carbonate, potassium bicarbonate, potassium carbonate: Bailingwei Technology Co., Ltd.

[0060] Main testing methods

[0061] Gas chromatograph: SHIMADZUGC-2010Plus. Column: Agilent WAX (60m × 320μm × 0.25μm). Injector temperature: 280℃. Detector temperature: 280℃. Temperature program: 50℃ for 5 min, ramp to 80℃ at 5℃ / min, hold for 0 min, then ramp to 280℃ at 25℃ / min, hold for 2 min. Carrier gas flow rate: 3 ml / min. Split ratio: 40:1.

[0062] The color of β-ionone was analyzed using a Hach LICO690 colorimeter.

[0063] The aroma of β-ionone was evaluated and identified by Beijing Beida Zhengyuan Technology Co., Ltd.

[0064] Example 1

[0065] The composition of the pseudoionone raw material is as follows: diacetone alcohol 1.09%, triacetone diol 0.07%, pseudoionone 85.17%, and substance I (C16H24O) 13.61%. The mass flow ratio of the pseudoionone raw material to n-hexane is 1:20, and they are continuously fed into a stirred mixing vessel and mixed to prepare a pseudoionone solution.

[0066] 98wt% sulfuric acid and pseudoionone solution were continuously fed into a microchannel reactor at rates of 60.4 kg / h and 1268.4 kg / h, respectively. The liquid holdup in the low-temperature section of the microchannel reactor was 534.7 mL, and the liquid holdup in the high-temperature section was 5346.8 mL. The residence times of the materials in the low-temperature and high-temperature sections were 1 s and 10 s, respectively. The reaction temperatures in the low-temperature and high-temperature sections were adjusted and controlled at 10℃ and 50℃, respectively. The discharge from the microchannel reactor and quenching water (302 kg / h) were continuously fed into the quenching vessel, maintaining a liquid holdup of 3262 kg in the quenching vessel. The material balance in and out of the quenching vessel was adjusted to ensure a quenching reaction residence time of 120 min, and the temperature inside the quenching vessel was adjusted to 50℃. The discharge from the quenching vessel was continuously fed into phase separator I, maintaining a liquid holdup of 3262 kg in phase separator I. The material balance in and out of phase separator I was adjusted to ensure a phase separation time of 120 min, and the temperature inside phase separator I was adjusted to 50℃. After the aqueous phase was separated by phase separator I, the oil phase I was sampled and analyzed by gas chromatography (0.049% diacetone alcohol, 0.003% triacetone diol, 0.051% ionone isomer, 3.942% β-ionone, 0.648% substance II (C16H24O), 0.062% tar, and the rest were mainly solvents). The yield of β-ionone was calculated to be 97.17% (based on the pseudo-ionone in the pseudo-ionone raw material).

[0067] Oil phase I and a 0.5 wt% sodium carbonate aqueous solution (115.1 kg / h) of deacidifying agent are continuously fed into the deacidification reactor, maintaining a liquid holdup of 2767 kg. The material balance between the feed and discharge of the deacidification reactor is adjusted to ensure a residence time of 120 min, and the temperature inside the deacidification reactor is adjusted to 50°C. The discharge from the deacidification reactor is continuously fed into phase separator II, maintaining a liquid holdup of 2767 kg in phase separator II. The material balance between the feed and discharge of phase separator II is adjusted to ensure a phase separation time of 120 min, and the temperature inside phase separator II is adjusted to 50°C.

[0068] After the deacidification residual phase is separated by phase separator II, the oil phase II and steam (120.8 kg / h) are continuously fed into the desolventizing column (theoretical number of trays is 18, the oil phase II stream is fed from the 8th tray, the steam is fed from the 13th tray, the pressure at the top and bottom of the column is 7.9 kPaA and 10.4 kPaA respectively, the bottom temperature is 120℃, and the reflux ratio is 10). The solvent is distilled off from the top of the column, and the desolventized material is distilled off from the bottom of the column. After solvent removal, the material continuously enters a scraped evaporator (pressure 0.15 MPaA, heating temperature 140℃, distillation temperature after vapor-phase condensation 110℃). The removed tar is discharged from the bottom, and the product distilled from the top (57.5 kg / h) is sampled and analyzed by gas chromatography (β-ionone 98.151%, no detectable impurities, the remainder being ionone isomers). The calculated yield of β-ionone for the entire process is 96.97% (based on pseudo-ionone and substance I (C16H24O) in the pseudo-ionone raw material). The product color is 75 Hazen (no significant color change after six months of storage at 25℃ in the dark and oxygen-free environment); aroma evaluation results: distinct violet and sweet fragrance, aroma qualified.

[0069] Example 2

[0070] The composition of the pseudoionone raw material is as follows: diacetone alcohol 1.49%, triacetone diol 0.07%, pseudoionone 81.93%, and substance I (C16H24O) 16.45%. The mass flow ratio of the pseudoionone raw material and dichloromethane is 1:2, and they are continuously fed into a stirred mixing vessel and mixed to prepare a pseudoionone solution.

[0071] 85wt% sulfuric acid and pseudoionone solution were continuously fed into a microchannel reactor at rates of 500.5 kg / h and 214.5 kg / h, respectively. The liquid holdup in the low-temperature section of the microchannel reactor was 2569.6 mL, and the liquid holdup in the high-temperature section was 5139.2 mL. The residence times of the materials in the low-temperature and high-temperature sections were 20 s and 40 s, respectively. The reaction temperatures in the low-temperature and high-temperature sections were adjusted to -30℃ and 20℃, respectively. The discharge from the microchannel reactor and quenching water (500.5 kg / h) were continuously fed into the quenching vessel, maintaining a liquid holdup of 203 kg in the quenching vessel. The material balance in and out of the quenching vessel was adjusted to ensure a quenching reaction residence time of 10 min, and the temperature inside the quenching vessel was adjusted to 5℃. The discharge from the quenching vessel was continuously fed into phase separator I, maintaining a liquid holdup of 203 kg in phase separator I. The material balance in and out of phase separator I was adjusted to ensure a phase separation time of 10 min, and the temperature inside phase separator I was adjusted to 5℃. After the aqueous phase was separated by phase separator I, the oil phase I was sampled and analyzed by gas chromatography (0.469% diacetone alcohol, 0.024% triacetone diol, 0.386% ionone isomer, 26.337% β-ionone, 5.444% substance II (C16H24O), 0.392% tar, and the rest were mainly solvents). The yield of β-ionone was calculated to be 97.08% (based on the pseudo-ionone in the pseudo-ionone raw material).

[0072] Oil phase I and a 10wt% potassium carbonate aqueous solution (14.2 kg / h) of deacidifying agent are continuously fed into the deacidification reactor, maintaining a liquid holdup of 38 kg. The material balance between the feed and discharge of the deacidification reactor is adjusted to ensure a residence time of 10 min, and the temperature inside the deacidification reactor is adjusted to 5°C. The discharge from the deacidification reactor is continuously fed into phase separator II, maintaining a liquid holdup of 38 kg in phase separator II. The material balance between the feed and discharge of phase separator II is adjusted to ensure a phase separation time of 10 min, and the temperature inside phase separator II is adjusted to 5°C.

[0073] After the deacidification residual phase is separated by phase separator II, the oil phase II and steam (4.2 kg / h) are continuously fed into the desolventizing column (theoretical number of trays: 30, oil phase II stream feed position: tray 14, steam feed position: tray 25, column top and bottom pressures: 24.5 kPaA and 28.8 kPaA respectively, column bottom temperature: 150℃, reflux ratio: 0.5). The solvent is distilled off from the top of the column, and the desolventized material is distilled off from the bottom of the column. After solvent removal, the material continuously enters a scraped evaporator (pressure 0.15 MPaA, heating temperature 140℃, distillation temperature after vapor-phase condensation 110℃). The removed tar is discharged from the bottom, and the product distilled from the top is sampled and analyzed by gas chromatography (β-ionone 98.135%, impurities 8.7 ppm, the remainder being ionone isomers). The calculated yield of β-ionone for the entire process is 96.86% (based on pseudo-ionone and substance I (C16H24O) in the pseudo-ionone raw material). The product color is 85 Hazen (no significant color change after six months of storage at 25℃ in the dark and oxygen-free environment); aroma evaluation results: distinct violet and sweet fragrance, aroma qualified.

[0074] Example 3

[0075] The composition of the pseudoionone raw material is as follows: diacetone alcohol 0.03%, triacetone diol 0.02%, pseudoionone 94.42%, and substance I (C16H24O) 5.48%. The mass flow ratio of the pseudoionone raw material to n-heptane is 1:4, and they are continuously fed into a stirred mixing vessel and mixed to prepare a pseudoionone solution.

[0076] 92wt% sulfuric acid and pseudoionone solution were continuously fed into a microchannel reactor at rates of 250.1 kg / h and 378.9 kg / h, respectively. The liquid holdup in the low-temperature section of the microchannel reactor was 1099.0 mL, and the liquid holdup in the high-temperature section was 3663.3 mL. The residence times of the materials in the low-temperature and high-temperature sections were 6 s and 20 s, respectively. The reaction temperatures in the low-temperature and high-temperature sections were adjusted and controlled at -10℃ and 35℃, respectively. The discharge from the microchannel reactor and quenching water (750.3 kg / h) were continuously fed into the quenching vessel, maintaining a liquid holdup of 1379 kg in the quenching vessel. The material balance in and out of the quenching vessel was adjusted to ensure a quenching reaction residence time of 60 min, and the temperature inside the quenching vessel was adjusted to 30℃. The discharge from the quenching vessel was continuously fed into phase separator I, maintaining a liquid holdup of 1379 kg in phase separator I. The material balance in and out of phase separator I was adjusted to ensure a phase separation time of 60 min, and the temperature inside phase separator I was adjusted to 30℃. After the aqueous phase was separated by phase separator I, the oil phase I was sampled and analyzed by gas chromatography (0.005% diacetone alcohol, 0.004% triacetone diol, 0.116% ionone isomer, 18.640% β-ionone, 1.096% substance II (C16H24O), 0.122% tar, and the rest were mainly solvents). The yield of β-ionone was calculated to be 98.69% (based on the pseudo-ionone in the pseudo-ionone raw material).

[0077] Oil phase I and a 3wt% sodium carbonate aqueous solution (4.1 kg / h) for deacidification are continuously fed into the deacidification reactor, maintaining a liquid holdup of 383 kg. The material balance between the feed and discharge of the deacidification reactor is adjusted to ensure a residence time of 60 min, and the temperature inside the deacidification reactor is adjusted to 30°C. The discharge from the deacidification reactor is continuously fed into phase separator II, maintaining a liquid holdup of 383 kg in phase separator II. The material balance between the feed and discharge of phase separator II is adjusted to ensure a phase separation time of 60 min, and the temperature inside phase separator II is adjusted to 30°C.

[0078] After the deacidification residual phase is separated by phase separator II, the oil phase II and steam (15.2 kg / h) are continuously fed into the desolventizing column (theoretical number of trays: 20; oil phase II stream feed position: 9th tray; steam feed position: 15th tray; top and bottom pressures: 4.7 kPaA and 7.6 kPaA, respectively; bottom temperature: 135℃; reflux ratio: 5). The solvent is distilled off from the top of the column, and the desolventized material is distilled off from the bottom of the column. After solvent removal, the material continuously enters a scraped evaporator (pressure 0.15 MPaA, heating temperature 140℃, distillation temperature after vapor-phase condensation 110℃). The removed tar is discharged from the bottom, and the product distilled from the top is sampled and analyzed by gas chromatography (β-ionone 99.170%, no detectable impurities, the remainder being ionone isomers). The calculated yield of β-ionone for the entire process is 98.50% (based on pseudo-ionone and substance I (C16H24O) in the pseudo-ionone raw material). The product color is 73 Hazen (no significant color change after six months of storage at 25℃ in the dark and oxygen-free environment); aroma evaluation results: distinct violet and sweet fragrance, aroma is qualified.

[0079] Example 4

[0080] The composition of the pseudoionone raw material is as follows: diacetone alcohol 0.54%, triacetone diol 0.03%, pseudoionone 90.30%, and substance I (C16H24O) 9.06%. The mass flow ratio of the pseudoionone raw material to dichloroethane is 1:6, and they are continuously fed into a stirred mixing vessel and mixed to prepare a pseudoionone solution.

[0081] 95wt% sulfuric acid and pseudoionone solution were continuously fed into a microchannel reactor at rates of 300.8 kg / h and 1052.8 kg / h, respectively. The liquid holdup in the low-temperature section of the microchannel reactor was 576.3 mL, and the liquid holdup in the high-temperature section was 4322.2 mL. The residence times of the materials in the low-temperature and high-temperature sections were 2 s and 15 s, respectively. The reaction temperatures in the low-temperature and high-temperature sections were adjusted to 0℃ and 40℃, respectively. The discharge from the microchannel reactor and quenching water (1203.2 kg / h) were continuously fed into the quenching vessel, maintaining a liquid holdup of 3835 kg in the quenching vessel. The material balance in and out of the quenching vessel was adjusted to ensure a quenching reaction residence time of 90 min, and the temperature inside the quenching vessel was adjusted to 40℃. The discharge from the quenching vessel was continuously fed into phase separator I, maintaining a liquid holdup of 3835 kg in phase separator I. The material balance in and out of phase separator I was adjusted to ensure a phase separation time of 90 min, and the temperature inside phase separator I was adjusted to 40℃. After the aqueous phase was separated by phase separator I, the oil phase I was sampled and analyzed by gas chromatography (0.071% diacetone alcohol, 0.005% triacetone diol, 0.081% ionone isomer, 12.446% β-ionone, 1.267% substance II (C16H24O), 0.090% tar, and the rest were mainly solvents). The yield of β-ionone was calculated to be 98.59% (based on the pseudo-ionone in the pseudo-ionone raw material).

[0082] Oil phase I and a 5wt% potassium bicarbonate aqueous solution (189.7 kg / h) of deacidifying agent are continuously fed into the deacidification reactor, maintaining a liquid holdup of 1898 kg. The material balance between the feed and discharge of the deacidification reactor is adjusted to ensure a residence time of 90 min, and the temperature inside the deacidification reactor is adjusted to 40℃. The discharge from the deacidification reactor is continuously fed into phase separator II, maintaining a liquid holdup of 1898 kg in phase separator II. The material balance between the feed and discharge of phase separator II is adjusted to ensure a phase separation time of 90 min, and the temperature inside phase separator II is adjusted to 40℃.

[0083] After the deacidification residual phase is separated by phase separator II, the oil phase II and steam (50.1 kg / h) are continuously fed into the desolventizing column (theoretical number of trays is 26, the oil phase II stream is fed from the 12th tray, the steam stream is fed from the 21st tray, the pressure at the top and bottom of the column is 5.7 kPaA and 9.4 kPaA respectively, the bottom temperature is 130℃, and the reflux ratio is 8). The solvent is distilled off from the top of the column, and the desolventized material is distilled off from the bottom of the column. After solvent removal, the material continuously enters a scraped evaporator (pressure 0.15 MPaA, heating temperature 140℃, distillation temperature after vapor-phase condensation 110℃). The removed tar is discharged from the bottom, and the product distilled from the top is sampled and analyzed by gas chromatography (β-ionone 99.021%, no detectable impurities, the remainder being ionone isomers). The calculated yield of β-ionone for the entire process is 98.34% (based on pseudo-ionone and substance I (C16H24O) in the pseudo-ionone raw material). The product color is 77 Hazen (no significant color change after six months of storage at 25℃ in the dark and oxygen-free environment); aroma evaluation results: distinct violet and sweet fragrance, aroma is qualified.

[0084] Example 5

[0085] The composition of the pseudoionone raw material is as follows: diacetone alcohol 2.13%, triacetone diol 0.08%, pseudoionone 75.78%, and substance I (C16H24O) 21.96%. The mass flow ratio of the pseudoionone raw material and toluene is 1:3, and they are continuously fed into a stirred mixing vessel and mixed to prepare a pseudoionone solution.

[0086] 90wt% sulfuric acid and pseudoionone solution were continuously fed into a microchannel reactor at rates of 450.4 kg / h and 400.4 kg / h, respectively. The liquid holdup in the low-temperature section of the microchannel reactor was 1955.1 mL, and the liquid holdup in the high-temperature section was 4887.7 mL. The residence times of the materials in the low-temperature and high-temperature sections were 10 s and 25 s, respectively. The reaction temperatures in the low-temperature and high-temperature sections were adjusted to -20℃ and 30℃, respectively. The discharge from the microchannel reactor and quenching water (900.8 kg / h) were continuously fed into the quenching vessel, maintaining a liquid holdup of 876 kg in the quenching vessel. The material balance in and out of the quenching vessel was adjusted to ensure a quenching reaction residence time of 30 min, and the temperature inside the quenching vessel was adjusted to 15℃. The discharge from the quenching vessel was continuously fed into phase separator I, maintaining a liquid holdup of 876 kg in phase separator I. The material balance in and out of phase separator I was adjusted to ensure a phase separation time of 30 min, and the temperature inside phase separator I was adjusted to 15℃. After the aqueous phase was separated by phase separator I, the oil phase I was sampled and analyzed by gas chromatography (0.505% diacetone alcohol, 0.019% triacetone diol, 0.247% ionone isomer, 18.361% β-ionone, 5.474% substance II (C16H24O), 0.281% tar, and the rest were mainly solvents). The yield of β-ionone was calculated to be 97.16% (based on the pseudo-ionone in the pseudo-ionone raw material).

[0087] Oil phase I and a 2wt% sodium bicarbonate aqueous solution (35.7 kg / h) for deacidification are continuously fed into the deacidification reactor, maintaining a liquid holdup of 219 kg. The material balance between the feed and discharge of the deacidification reactor is adjusted to ensure a residence time of 30 min, and the temperature inside the deacidification reactor is adjusted to 15℃. The discharge from the deacidification reactor is continuously fed into phase separator II, maintaining a liquid holdup of 219 kg in phase separator II. The material balance between the feed and discharge of phase separator II is adjusted to ensure a phase separation time of 30 min, and the temperature inside phase separator II is adjusted to 15℃.

[0088] After the deacidification residual phase is separated by phase separator II, the oil phase II and steam (13.3 kg / h) are continuously fed into the desolventizing column (theoretical number of trays is 23, the oil phase II stream is fed from the 10th tray, the steam is fed from the 18th tray, the pressure at the top and bottom of the column is 2.9 kPaA and 6.2 kPaA respectively, the bottom temperature is 140℃, and the reflux ratio is 2). The solvent is distilled off from the top of the column, and the desolventized material is distilled off from the bottom of the column. After solvent removal, the material continuously enters a scraped evaporator (pressure 0.15 MPaA, heating temperature 140℃, distillation temperature after vapor-phase condensation 110℃). The removed tar is discharged from the bottom, and the product distilled from the top is sampled and analyzed by gas chromatography (β-ionone 98.129%, impurities 1.4 ppm, the remainder being ionone isomers). The calculated yield of β-ionone for the entire process is 96.89% (based on pseudo-ionone and substance I (C16H24O) in the pseudo-ionone raw material). The product color is 81 Hazen (no significant color change after six months of storage at 25℃ in the dark and oxygen-free environment); aroma evaluation results: distinct violet and sweet fragrance, aroma is qualified.

[0089] Comparative Example 1

[0090] The composition of the pseudoionone raw material is as follows: diacetone alcohol 0.03%, triacetone diol 0.02%, pseudoionone 94.42%, and substance I (C16H24O) 5.48%. The mass flow ratio of the pseudoionone raw material to n-heptane is 1:4, and they are continuously fed into a stirred mixing vessel and mixed to prepare a pseudoionone solution.

[0091] 92wt% sulfuric acid and pseudoionone solution were continuously fed into a microchannel reactor at rates of 250.9 kg / h and 380.2 kg / h, respectively. The liquid holdup in the low-temperature section of the microchannel reactor was 1099.0 mL, and the liquid holdup in the high-temperature section was 3663.3 mL. The residence times of the materials in the low-temperature and high-temperature sections were 6 s and 20 s, respectively. The reaction temperatures in the low-temperature and high-temperature sections were adjusted and controlled at -10℃ and 35℃, respectively. The discharge from the microchannel reactor and quenching water (752.7 kg / h) were continuously fed into the quenching vessel, maintaining a liquid holdup of 1384 kg in the quenching vessel. The material balance in and out of the quenching vessel was adjusted to ensure a quenching reaction residence time of 60 min, and the temperature inside the quenching vessel was adjusted to 30℃. The discharge from the quenching vessel was continuously fed into phase separator I, maintaining a liquid holdup of 1384 kg in phase separator I. The material balance in and out of phase separator I was adjusted to ensure a phase separation time of 60 min, and the temperature inside phase separator I was adjusted to 30℃. After the aqueous phase was separated by phase separator I, the oil phase I was sampled and analyzed by gas chromatography (0.005% diacetone alcohol, 0.004% triacetone diol, 0.118% ionone isomer, 18.635% β-ionone, 1.096% substance II (C16H24O), 0.125% tar, and the rest were mainly solvents). The yield of β-ionone was calculated to be 98.66% (based on the pseudo-ionone in the pseudo-ionone raw material).

[0092] Oil phase I and a 3wt% sodium carbonate aqueous solution (4.2 kg / h) for deacidification are continuously fed into the deacidification reactor, maintaining a liquid holdup of 384 kg. The material balance between the feed and discharge of the deacidification reactor is adjusted to ensure a residence time of 60 min, and the temperature inside the deacidification reactor is adjusted to 30°C. The discharge from the deacidification reactor is continuously fed into phase separator II, maintaining a liquid holdup of 384 kg in phase separator II. The material balance between the feed and discharge of phase separator II is adjusted to ensure a phase separation time of 60 min, and the temperature inside phase separator II is adjusted to 30°C.

[0093] After the deacidification residual phase is separated by phase separator II, the oil phase II is continuously fed into the desolventizing column (theoretical plate number is 20, the oil phase II stream feed position is the 9th plate, the pressure at the top and bottom of the column is 4.7 kPaA and 7.6 kPaA respectively, the bottom temperature is 135℃, and the reflux ratio is 5). The solvent is distilled off from the top of the column, and the desolventized material is distilled off from the bottom of the column. The desolventized material is continuously fed into a scraped evaporator (pressure 0.15 MPaA, heating temperature 140℃, distillation temperature after vapor condensation is 110℃). The removed tar is discharged from the bottom, and the product distilled off from the top is sampled and analyzed by gas chromatography (β-ionone 92.718%, impurity ketone content 46501 ppm, the remainder being ionone isomers). The calculated yield of β-ionone for the entire process is 94.71% (based on pseudo-ionone and substance I (C16H24O) in the pseudo-ionone feedstock). The product's color is 257 Hazen (it will change to 377 Hazen after six months of storage at 25℃ away from light and oxygen); the fragrance evaluation result is: weak floral fragrance, insufficient sweet fragrance, and the fragrance is not up to standard.

[0094] Comparative Example 2

[0095] 0.2081g of substance II, 0.2006g of acetone, 0.2043g of diacetone alcohol, and 0.2079g of triacetone diol were added to 60kg of the β-ionone product from Example 3. The mixture was thoroughly mixed to achieve a ketone content of 14ppm and a β-ionone purity of 99.169%. The color of the mixed product was 89 Hazen (it changed to 136 Hazen after six months of storage at 25°C in the dark and oxygen-free environment). Fragrance evaluation results: A distinct violet floral and sweet fragrance; the floral fragrance is sufficient, but the sweet fragrance is slightly lacking; the aroma is not up to standard.

[0096] It is readily understood that the above embodiments are merely illustrative examples for clear explanation and do not imply that the invention is limited thereto. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A β-ionone, characterized in that, It contains ≤10ppm of heteroketone substances, including substance II, acetone, diacetone alcohol, and triacetone diol; Substance II includes , , , , , And their cis, trans, and optical isomers; Preferably, the purity of the β-ionone is 97% or higher, more preferably 98% or higher.

2. The method for preparing β-ionone according to claim 1, characterized in that, Includes the following steps: (1) The pseudo-ionone raw material and solvent are mixed to prepare a pseudo-ionone solution; (2) The pseudo-ionone solution and sulfuric acid were each continuously introduced into a microchannel reactor for reaction; (3) The material from the microchannel reactor and the quenching water are continuously fed into the quenching vessel to quench the reaction output; (4) The material discharged from the quenching kettle is continuously collected and enters the phase separator I for phase separation operation to obtain oil phase I and water phase; (5) The oil phase I and the deacidifying agent are continuously introduced into the deacidification kettle and stirred to mix for neutralization and deacidification; (6) The material discharged from the deacidification kettle is continuously fed into phase separator II for phase separation operation to obtain oil phase II and deacidification residue phase; (7) Oil phase II and vapor are each continuously fed into the desolventizing tower for desolventizing operation; (8) The material is continuously collected from the bottom of the desolventizing tower and enters the scraped evaporator for tar removal. The top distillate is the product β-ionone.

3. The preparation method according to claim 2, characterized in that, In step (1), the mass ratio of solvent to pseudoionone raw material is 2~20, preferably 3~10. The solvent is one or more of benzene compounds, chloroalkanes and alkanes, preferably one or more of toluene, dichloroethane, dichloromethane, n-heptane and n-hexane.

4. The preparation method according to claim 2 or 3, characterized in that, In step (1), the pseudo-ionone raw material contains less than 25 wt% of diacetone alcohol, triacetone diol and substance I, and the purity of the pseudo-ionone raw material is above 70%, preferably above 75%.

5. The preparation method according to claim 2, characterized in that, In step (2), the microchannel reactor has a low-temperature section and a high-temperature section. The pseudo-ionone solution and sulfuric acid first enter the low-temperature section to react. The material coming out of the low-temperature section flows into the high-temperature section to continue the reaction. The reaction temperatures of the material in the low-temperature section and the high-temperature section are -30~10℃ and 20~50℃, respectively. The residence time of the material in the low-temperature section and the high-temperature section is 1~20s and 10~40s, respectively. Preferably, the sulfuric acid concentration is 85wt%~98wt%; the mass flow ratio of sulfuric acid to pseudoionone raw material is 1~7.

6. The preparation method according to claim 2 or 5, characterized in that, The quenching temperature of the quenching vessel in step (3) is 5~50℃, and the quenching residence time is 10~120min; Preferably, the mass flow ratio of quenching water introduced into the quenching vessel to the feed sulfuric acid entering the microreactor is 5 to 1.

7. The preparation method according to claim 2, characterized in that, In step (4), the phase separation temperature of phase separator I is 5~50℃ and the phase separation dwell time is 10~120min.

8. The preparation method according to claim 2, characterized in that, In step (5), the deacidifying agent is an inorganic weak base, preferably an aqueous solution of potassium bicarbonate, potassium carbonate, sodium bicarbonate and sodium carbonate with a concentration of 0.5wt%~10wt%. Preferably, the neutralization temperature of the deacidification kettle is 5~50℃, the neutralization residence time is 10~120min, and the mass flow ratio of the deacidifying agent and the pseudoionone raw material is 1:(0.5~18).

9. The preparation method according to claim 2, characterized in that, In step (6), the phase separation temperature of phase separator II is 5~50℃ and the phase separation dwell time is 10~120min.

10. The preparation method according to claim 2, characterized in that, In step (7), the mass flow ratio of the desolventizing steam to the pseudoionone raw material is 1:(0.5~17); The theoretical number of trays in the solvent removal column is 18~30. The feed positions of the oil phase II stream and the vapor stream entering the solvent removal column are one of the 8th to 14th trays and one of the 13th to 25th trays, respectively. The reflux ratio is 0.5~10, the column bottom temperature is 120~150℃, the column top pressure is 2.9~24.5kPaA, and the column bottom pressure is 6~30kPaA.

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