Production process of beta-ionone

Abstract

The present invention relates to the technical field of chemical synthesis, and discloses a beta-ionone production process, which comprises: (1) pre-cooling a pseudoionone solution and an acid catalyst through a spiral winding pipe type heat exchanger, and feeding the pre-cooled pseudoionone solution and the pre-cooled acid catalyst into a dynamic stirring pipe type reactor to carry out a mixing reaction to obtain a mixed reaction liquid; and (2) feeding the mixed reaction liquid and a quenching agent pre-cooled by a spiral winding tubular heat exchanger into a dynamic stirring tubular reactor for quenching, and splitting phases to obtain the beta-ionone. The spiral winding pipe type heat exchanger and the dynamic stirring pipe type reactor are connected for use, so that the pre-cooling, mixing and heat transfer effects of materials can be improved, local overheating and generation of tar byproducts are reduced, and the reaction selectivity and yield of beta-ionone are improved; and continuous and stable production can be realized, and the method is suitable for industrial amplification application.

Description

Technical Field

[0001] This invention relates to the field of chemical synthesis technology, specifically to a production process for β-ionone. Background Technology

[0002] β-Ionone is an important fine chemical product, widely used in fragrances, pharmaceutical intermediates, and vitamins. In existing technologies, β-ionone is typically prepared by a cyclization reaction of pseudoionone under acidic conditions, followed by quenching, phase separation, and post-treatment to obtain the target product.

[0003] However, the cyclization reaction of pseudoionones under acidic conditions is typically a fast-paced, highly exothermic reaction system. Once the raw materials come into contact with the acidic catalyst, a localized environment of instantaneous high temperature and high acid concentration can easily form, inducing side reactions such as isomerization and tarring. This leads to decreased selectivity and yield of β-ionone, as well as a darker product color and increased system viscosity. These problems are particularly pronounced under scale-up production conditions if the heat of reaction cannot be removed promptly and rapid, uniform mixing is not achieved.

[0004] Existing β-ionone production processes mostly employ batch reactors for preparation. While this type of process is relatively common, it typically suffers from limited mixing efficiency, insufficient heat transfer efficiency, difficulty in localized temperature control, and long overall reaction and quenching times. Under strongly exothermic reaction conditions, batch reactor processes are prone to localized overheating, excessively high localized acid concentrations, and uneven material residence time distribution, which exacerbates side reactions and increases tar byproducts, hindering the production of high-purity, high-yield β-ionone. Furthermore, batch reactor processes often exhibit insufficient batch-to-batch stability, low continuity, and increased control difficulty after industrial scale-up.

[0005] To improve reaction process control, existing technologies have attempted to employ continuous flow equipment, especially small-sized reaction devices such as microchannels, to shorten heat and mass transfer distances and enhance reaction regulation. However, such equipment still has significant limitations when handling reaction systems like β-ionone, which are strongly exothermic, have rapidly changing system composition, and are prone to generating high-viscosity byproducts. On the one hand, microchannels require high feed uniformity, flow stability, and system cleanliness. On the other hand, the formation of localized high-viscosity zones or tar-like deposits during the reaction process can easily lead to increased pressure drop, channel blockage, and unstable continuous operation, thus affecting process stability and scale-up applications.

[0006] Furthermore, the quenching stage in β-ionone production is also a crucial factor affecting the final product quality. If the material after the cyclization reaction is not quenched in a timely and uniform manner, side reactions may continue to occur locally, further increasing the formation of isomers and tar byproducts, thus affecting product purity and yield. Existing quenching processes often suffer from problems such as untimely cooling, insufficient mixing, and poor phase separation, leading to incomplete reaction termination and requiring further improvement in overall process stability.

[0007] Therefore, there is still an urgent need for a β-ionone production process that can take into account rapid precooling, enhanced mixing, precise temperature control, timely quenching, reduced tar by-product formation, and is suitable for continuous and stable operation, so as to overcome the shortcomings of existing reactor processes and microchannel processes in industrial applications. Summary of the Invention

[0008] This invention provides a production process for β-ionone to solve the problems in the prior art, such as the exothermic reaction of β-ionone, difficulty in local temperature control, easy generation of tar byproducts, easy equipment blockage, and difficulty in achieving stable and continuous production.

[0009] In a first aspect, the present invention provides a process for producing β-ionone, comprising the following steps: (1) The pseudo ionone solution and acidic catalyst were pre-cooled by a spiral wound tube heat exchanger and then sent to a dynamic stirred tube reactor for mixing and reaction to obtain a mixed reaction solution; (2) The mixed reaction liquid and the quenching agent pre-cooled by the spiral wound tube heat exchanger are sent into the dynamic stirred tube reactor for quenching, and then the phases are separated to obtain the β-ionone.

[0010] It should be noted that the spiral wound tube heat exchanger can be a conventional spiral wound tube heat exchanger in the existing technology, as long as it can meet the requirements for heat exchange and precooling of pseudo-ionone solution, acidic catalyst, and quenching agent.

[0011] The dynamic stirred tubular reactor only needs to meet the requirements of dynamic stirring and mixing of materials and enhanced heat and mass transfer under continuous conveying conditions. Its specific structural form is not particularly limited, and conventional dynamic stirred tubular reactors in the existing technology can be used.

[0012] In this invention, the pseudo-ionone solution, acidic catalyst, and quencher are first pre-cooled by a spiral wound tubular heat exchanger, and then combined with a dynamic stirred tubular reactor for cyclization reaction and quenching treatment. This enables rapid heat exchange, rapid mixing, and accurate local temperature control before and after material contact, thereby effectively reducing the exothermic shock at the moment of material contact, reducing local overheating, excessive local reaction, and the generation of tar byproducts, lowering the probability of side reactions, and helping to shorten the reaction time, improve the stability of the reaction process, and enhance the purity and yield of β-ionone.

[0013] Furthermore, as one embodiment of the present invention, the mass fraction of pseudoionone in the pseudoionone solution is 5% to 50%, preferably 5% to 30%; for example, the mass fraction of pseudoionone in the pseudoionone solution is 5%, 10%, 15%, 30%, 40%, or 50%.

[0014] The pseudoionone solution is prepared by dissolving pseudoionone in an organic solvent, which includes one or more of dichloroethane, n-heptane, benzene, toluene, chloroform, carbon tetrachloride, and trichloroethane.

[0015] Furthermore, as one embodiment of the present invention, the acidic catalyst comprises a sulfuric acid solution with a mass fraction of 88% to 98%; for example, the sulfuric acid solution contains sulfuric acid with a mass fraction of 88%, 90%, 92%, 95%, or 98%.

[0016] Furthermore, as an embodiment of the present invention, in step (1), the mass ratio of the pseudo-ionone solution to the acidic catalyst is (3-24):1; preferably (3.85-23.08):1.

[0017] Furthermore, as an embodiment of the present invention, in step (1), the feed rate of the pseudo-ionone solution into the dynamic stirred tubular reactor is 8 kg / min to 15 kg / min; Furthermore, as one embodiment of the present invention, the feed rate of the sulfuric acid solution into the dynamic stirred tubular reactor is 0.65 kg / min to 2.6 kg / min.

[0018] Furthermore, as an embodiment of the present invention, in step (1), the pseudo-ionone solution is pre-cooled to -60℃ to 5℃, preferably -60℃ to 0℃, by a spiral wound tube heat exchanger; for example, the temperature of the pseudo-ionone solution after pre-cooling by the spiral wound tube heat exchanger is -60℃, -50℃, -30℃, 0℃, 5℃.

[0019] Furthermore, as an embodiment of the present invention, in step (1), the acidic catalyst is pre-cooled to 0℃~15℃, preferably 0℃~10℃, by a spiral wound tube heat exchanger; for example, the temperature of the acidic catalyst after pre-cooling by the spiral wound tube heat exchanger is 0℃, 2℃, 5℃, 10℃, or 15℃.

[0020] Furthermore, as an embodiment of the present invention, in step (1), the temperature conditions of the dynamic stirred tubular reactor are controlled to be -40℃ to 40℃, preferably -40℃ to 30℃, and more preferably -40℃ to -10℃; For example, in step (1), the temperature conditions of the dynamic stirred tubular reactor are controlled as -40℃, -30℃, 0℃, 30℃, and 40℃.

[0021] Furthermore, as an embodiment of the present invention, in step (1), the liquid holding capacity of the dynamic stirred tubular reactor is controlled to be 2 kg to 13 kg, preferably 2.6 kg to 12.6 kg; Furthermore, as an embodiment of the present invention, in step (1), the reaction residence time of the dynamic stirred tubular reactor is controlled to be 5s to 7.5min, preferably 10s to 60s; for example, in step (1), the reaction residence time of the dynamic stirred tubular reactor is controlled to be 5s, 10s, 30s, 60s, 5min, or 7.5min.

[0022] Furthermore, as an embodiment of the present invention, in step (2), the temperature conditions inside the dynamic stirred tubular reactor are controlled to be 25°C to 70°C; for example, in step (2), the temperature conditions inside the dynamic stirred tubular reactor are controlled to be 25°C, 30°C, 50°C, and 70°C.

[0023] Furthermore, as one embodiment of the present invention, in step (2), the quenching agent is pre-cooled to 3°C to 15°C via a spiral wound tube heat exchanger. For example, in step (2), the quenching agent is pre-cooled to 3°C, 5°C, 10°C, and 15°C via a spiral wound tube heat exchanger.

[0024] Furthermore, as one embodiment of the present invention, in step (2), the liquid holding capacity of the dynamic stirred tubular reactor is 16.5 kg to 99 kg.

[0025] Furthermore, as an embodiment of the present invention, in step (2), the reaction residence time of the dynamic stirred tubular reactor is 1 min to 10 min, preferably 1 min to 6 min; for example, in step (2), the reaction residence time of the dynamic stirred tubular reactor is 1 min, 3 min, 6 min, or 10 min.

[0026] Furthermore, as one embodiment of the present invention, the quenched material is fed into an online liquid-liquid phase separator for phase separation; Preferably, the temperature conditions for phase separation are controlled at 25℃ to 70℃; for example, the temperature conditions for phase separation are controlled at 25℃, 30℃, 50℃, and 70℃.

[0027] Preferably, the liquid holdup of the online liquid-liquid phase separator is controlled to be 16.5 kg to 99 kg.

[0028] In a second aspect, the present invention provides a production apparatus for β-ionone, comprising a raw material feeding unit, a cyclization reaction unit, a quenching reaction unit and a phase separation unit connected in sequence. The cyclization reaction unit includes a first heat exchanger, a second heat exchanger, and a cyclization reactor. The inlets of the first and second heat exchangers are respectively connected to the feeding unit, the outlets of the first and second heat exchangers are respectively connected to the inlet of the cyclization reactor, and the outlet of the cyclization reactor is connected to the quenching reaction unit. Wherein, the first heat exchanger and / or the second heat exchanger are spiral wound tube heat exchangers, and the ring reactor is a dynamic stirred tube reactor.

[0029] A spiral wound tube heat exchanger includes a shell, a tube sheet, and a spiral wound tube bundle disposed within the shell. The spiral wound tube bundle is formed by winding multiple heat exchange tubes. The material to be heat-exchanged and the heat exchange medium flow in different channels and exchange heat through the tube walls. Because the heat exchange tubes are arranged in a spiral wound configuration, heat transfer is enhanced, and heat exchange efficiency is improved.

[0030] A dynamic stirred tubular reactor is a reaction device that combines tubular continuous reaction and dynamic stirring mixing functions. It includes a reaction pipe and a dynamic stirring component installed in the reaction pipe. The dynamic stirring component moves under the drive of a drive device to achieve continuous mixing of the materials entering the reaction pipe during continuous flow.

[0031] Furthermore, as an embodiment of the present invention, the raw material feeding unit includes at least a pseudo-ionone feeding device and a sulfuric acid feeding device, the inlet of the first heat exchanger is connected to the pseudo-ionone feeding device, and the inlet of the second heat exchanger is connected to the sulfuric acid feeding device.

[0032] The pseudo-ionone feeding device refers to a device used to store and continuously feed pseudo-ionone material to the first heat exchanger, including a pseudo-ionone feeding tank, a conveying pipeline connected to the pseudo-ionone feeding tank, and a conveying pump installed on the conveying pipeline.

[0033] A sulfuric acid feeding device is a device used to store and continuously supply sulfuric acid material to a second heat exchanger. It may include a sulfuric acid feeding tank, a conveying pipeline connected to the sulfuric acid feeding tank, and a conveying pump installed on the conveying pipeline.

[0034] This invention, by setting up a pseudo-ionone feeding device and a sulfuric acid feeding device, can achieve independent storage, stable transportation and continuous feeding of pseudo-ionone material and sulfuric acid material respectively, thereby facilitating subsequent heat exchange treatment and entry into the cyclization reactor for reaction.

[0035] Furthermore, as one embodiment of the present invention, the first heat exchanger is arranged vertically, the inlet at the bottom of the first heat exchanger is connected to the pseudo-ionone feeding device, and the outlet at the top of the first heat exchanger is connected to the cyclic reactor.

[0036] Furthermore, in one embodiment of the present invention, the second heat exchanger is arranged vertically, the inlet at the bottom of the second heat exchanger is connected to the sulfuric acid feeding device, and the outlet at the top of the second heat exchanger is connected to the cyclic reactor.

[0037] It should be explained that the first and second heat exchangers are arranged vertically, meaning that the axial direction of the first and second heat exchangers extends vertically, that is, the heat exchangers are arranged vertically as a whole. Accordingly, both the first and second heat exchangers adopt a bottom-feed and top-discharge connection method, that is, the material enters from the bottom of the heat exchanger, flows and exchanges heat vertically inside the heat exchanger, and then flows out from the top and enters the ring reactor.

[0038] Furthermore, as one embodiment of the present invention, the quenching reaction unit includes a quenching agent feeding device, a third heat exchanger, and a quenching reactor. The inlet of the third heat exchanger is connected to the quenching agent feeding device, and the outlets of the third heat exchanger and the cyclic reactor are respectively connected to the inlet of the quenching reactor. The outlet of the quenching reactor is connected to the phase separation unit.

[0039] Furthermore, as one embodiment of the present invention, the quenching reactor is a dynamic stirred tube reactor.

[0040] The dynamic stirred tube reactor includes a reaction pipe, a dynamic stirring component disposed within the reaction pipe, and a drive device for moving the dynamic stirring component. The dynamic stirring component moves under the drive device, ensuring continuous mixing of the material entering the reaction pipe during continuous flow. Since the quenching process also requires sufficient contact and rapid heat transfer within a short time, using a dynamic stirred tube reactor as the quenching reactor enhances the mixing, mass transfer, and heat transfer processes between the cyclization reaction liquid and the quenching agent. This allows the cyclization reaction liquid to be quenched quickly and uniformly, reducing side reactions caused by localized continued reaction, and improving the product quality and production stability of β-ionone.

[0041] Furthermore, as one embodiment of the present invention, the quenching reactor is a horizontally arranged dynamic stirred tube reactor.

[0042] The quenching reactor is a horizontally positioned, dynamically stirred tubular reactor. This means the reactor extends horizontally along its axis and incorporates dynamic stirring components within it, ensuring continuous mixing of the cyclization reaction liquid and the quenching agent during continuous flow. The horizontal configuration facilitates piping connections to the upstream third heat exchanger and subsequent phase separation units, making it suitable for continuous production equipment arranged sequentially along the process flow. Furthermore, it promotes stable material flow within the reactor, ensuring the completion of the quenching process and improving equipment operational stability. Simultaneously, the dynamic stirring further enhances mixing and heat transfer during quenching, ensuring rapid and uniform contact between the cyclization reaction liquid and the quenching agent, reducing side reactions caused by localized continuation of the reaction.

[0043] Furthermore, as one embodiment of the present invention, the cyclone reactor is a horizontally arranged dynamic stirred tube reactor.

[0044] Furthermore, as one embodiment of the present invention, the third heat exchanger is a spiral wound tube heat exchanger.

[0045] The third heat exchanger is a spiral wound tube heat exchanger. Utilizing the structural characteristics of the spiral wound tube bundle, it can efficiently exchange heat with the quenching agent, allowing the quenching agent to reach the predetermined temperature before entering the quenching reactor, thereby improving the temperature control effect of the quenching process.

[0046] Furthermore, in one embodiment of the present invention, the third heat exchanger is arranged vertically, the inlet at the bottom of the third heat exchanger is connected to the quenching agent feeding device, and the outlet at the top of the third heat exchanger is connected to the quenching reactor.

[0047] The third heat exchanger, namely the spiral wound tube heat exchanger, is set vertically. This means that the axial direction of the spiral wound tube heat exchanger extends vertically and adopts a bottom-feed and top-discharge method. That is, the quenching agent enters from the bottom of the third heat exchanger, flows vertically in the spiral wound tube heat exchanger and completes heat exchange, and then flows out from the top and enters the quenching reactor.

[0048] Furthermore, as one embodiment of the present invention, the phase separation unit includes an online liquid-liquid phase separator, an organic phase receiving device, and an aqueous phase receiving device; The outlet of the quenching reactor is connected to the inlet of the online liquid-liquid phase separator, the organic phase outlet of the online liquid-liquid phase separator is connected to the organic phase receiving device, and the aqueous phase outlet of the online liquid-liquid phase separator is connected to the aqueous phase receiving device.

[0049] An online liquid-liquid phase separator is a device installed in a continuous process flow for the continuous stratification and separation of two immiscible liquid phase mixtures. The term "online" means that the liquid-liquid phase separator is directly installed between the quenching reactor and the receiving device, so that the quenched mixture can continuously enter the phase separator and complete the phase separation without intermediate transfer.

[0050] An online liquid-liquid phase separator includes at least a phase separator housing, an inlet, an organic phase outlet, and an aqueous phase outlet disposed on the phase separator housing. The phase separator housing contains a phase-separation space for the mixture to remain and undergo liquid-liquid stratification. After the quenched mixture enters the phase separator housing, it gradually stratifies within the phase-separation space based on the density difference between the different liquid phases and gravitational settling. The less dense phase, as the organic phase, is discharged from the organic phase outlet, and the more dense phase, as the aqueous phase, is discharged from the aqueous phase outlet, thereby achieving continuous phase separation of the quenched mixture. Preferably, the online liquid-liquid phase separator may also include flow guiding components, flow stabilizing components, and / or liquid level control components to reduce feed disturbance, stabilize the phase interface, and improve the phase separation effect.

[0051] The technical solution of this invention has the following advantages: In this invention, the pseudo-ionone solution and the acidic catalyst are pre-cooled by a spiral wound tube heat exchanger before entering the dynamic stirred tube reactor, which can effectively reduce the exothermic intensity of the two materials at the moment of contact. At the same time, the dynamic stirred tube reactor has good mixing, mass transfer and heat transfer capabilities, which is conducive to improving the accuracy of local temperature control during the reaction process, reducing isomerization and tar by-product formation caused by local overheating, thereby improving the reaction selectivity and yield of β-ionone.

[0052] Furthermore, this process also employs a combination of "pre-cooling with a spiral-wound tube heat exchanger and quenching with a dynamically stirred tube reactor" during the quenching stage. This allows the quenching agent to rapidly and uniformly contact the mixed reaction solution at a lower temperature, facilitating timely termination of the reaction and heat removal, thus reducing subsequent side reactions. Therefore, this process not only improves the product quality of β-ionone but also offers advantages for continuous, stable, and industrialized production. Attached Figure Description

[0053] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0054] Figure 1 This is a schematic diagram of the assembly structure of the production equipment for β-ionone of the present invention.

[0055] Explanation of reference numerals in the attached figures: 1. False ionone feed tank; 2. False ionone feed pump; 3. First heat exchanger; 4. Sulfuric acid feed tank; 5. Sulfuric acid feed pump; 6. Second heat exchanger; 7. Cyclic reactor; 8. Quenching agent feed tank; 9. Quenching agent feed pump; 10. Third heat exchanger; 11. Quenching reactor; 12. Online liquid-liquid phase separator; 13. Organic phase receiving device; 14. Aqueous phase receiving device. Detailed Implementation

[0056] To better understand the present invention, the following embodiments are provided for further explanation. However, the following embodiments do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the scope of protection of the present invention.

[0057] 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 application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having” and any variations thereof in the text of this application are intended to cover non-exclusive inclusion.

[0058] In the description of the embodiments of this application, the technical terms "first", "second", etc. are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features.

[0059] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0060] The dynamic stirred tubular reactor used in this embodiment of the invention is the tubular reactor disclosed in patent application CN 110013818 A, and its specific structure can be found in Figures 12 and 13 of that patent application. It should be understood that the reference to the specific reactor described above is merely for illustrative purposes to illustrate the possible equipment forms that can be used in this invention and does not constitute a limitation on the scope of protection of this invention.

[0061] Example 1 like Figure 1 As shown, this embodiment provides a production apparatus for β-ionone, comprising a raw material feeding unit, a cyclization reaction unit, a quenching reaction unit, and a phase separation unit connected in sequence. The raw material feeding unit includes at least a pseudoionone feeding device and a sulfuric acid feeding device; the cyclization reaction unit includes a first heat exchanger 3, a second heat exchanger 6, and a cyclization reactor 7; the quenching reaction unit includes a quenching agent feeding device, a third heat exchanger 10, and a quenching reactor 11; the phase separation unit includes an online liquid-liquid phase separator 12, an organic phase receiving device 13, and an aqueous phase receiving device 14.

[0062] The device includes a pseudo-ionone feeding unit, comprising a pseudo-ionone feeding tank 1 connected to a first heat exchanger 3 via a pipeline, on which a pseudo-ionone feeding pump 2 is installed. The sulfuric acid feeding unit includes a sulfuric acid feeding tank 4 connected to a second heat exchanger 6 via a pipeline, on which a sulfuric acid feeding pump 5 is installed. The quenching agent feeding unit includes a quenching agent feeding tank 8 connected to a third heat exchanger 10 via a pipeline, on which a quenching agent feeding pump 9 is installed. The pseudo-ionone feeding pump 2, sulfuric acid feeding pump 5, and quenching agent feeding pump 9 are all used to continuously transport the corresponding materials to subsequent processing units, preferably metering pumps capable of stable quantitative delivery. Depending on actual production needs, valves, flow meters, pressure gauges, and temperature sensors can also be installed on each feeding pipeline to adjust and monitor the feeding status.

[0063] In this embodiment, the inlet of the first heat exchanger 3 is connected to the pseudo-ionone feeding device, the inlet of the second heat exchanger 6 is connected to the sulfuric acid feeding device, and the outlets of the first heat exchanger 3 and the second heat exchanger 6 are respectively connected to the inlet of the cyclic reactor 7. The outlet of the cyclic reactor 7 is connected to the quenching reaction unit. Preferably, both the first heat exchanger 3 and the second heat exchanger 6 are spiral wound tube heat exchangers and are both arranged vertically. Further, the inlet at the bottom of the first heat exchanger 3 is connected to the pseudo-ionone feeding device, and the outlet at the top of the first heat exchanger 3 is connected to the cyclic reactor 7; the inlet at the bottom of the second heat exchanger 6 is connected to the sulfuric acid feeding device, and the outlet at the top of the second heat exchanger 6 is connected to the cyclic reactor 7. This vertical arrangement and bottom-feeding, top-discharging connection facilitates continuous and stable flow of materials within the heat exchangers and ensures sufficient heat exchange of the materials.

[0064] The first heat exchanger 3 is used to pre-cool the pseudo-ionone material, and the second heat exchanger 6 is used to pre-cool the sulfuric acid material, so that both materials reach the required reaction temperature range before entering the cyclic reactor 7, thereby reducing the intensity of localized heat release upon entering the cyclic reactor 7. The spiral wound tube heat exchanger features high heat exchange efficiency, continuous flow channels, and a relatively small footprint, and can meet the pre-cooling requirements of continuously conveyed materials. The first heat exchanger 3 and the second heat exchanger 6 can be equipped with flow channel structures suitable for continuous heat exchange, and a cooling medium can be introduced to achieve heat exchange and cooling. The cooling medium can be selected from chilled brine, coolant, or other suitable media according to process requirements.

[0065] The cyclization reactor 7 is a dynamic stirred tubular reactor, preferably horizontally arranged. The dynamic stirred tubular reactor includes a tubular reaction chamber and a dynamic stirring component disposed within the tubular reaction chamber. The dynamic stirring component rotates under the drive of a driving device to continuously mix and enhance heat transfer of the materials entering the reactor. Since the cyclization reaction of pseudoionone with acidic materials is exothermic upon contact, using a dynamic stirred tubular reactor helps improve the uniformity of material contact, reduce local concentration and temperature differences, and lower the risk of side reactions and tar formation. In actual operation, the pseudoionone material pre-cooled by the first heat exchanger 3 and the sulfuric acid material pre-cooled by the second heat exchanger 6 enter the cyclization reactor 7 respectively. They continuously contact and undergo a cyclization reaction within the cyclization reactor 7, generating a reaction liquid containing β-ionone, which is then continuously output from the outlet of the cyclization reactor 7 to the quenching reaction unit.

[0066] In the quenching reaction unit, the inlet of the third heat exchanger 10 is connected to the quenching agent feeding device, and the outlets of the third heat exchanger 10 and the cyclization reactor 7 are respectively connected to the inlet of the quenching reactor 11. The outlet of the quenching reactor 11 is connected to the phase separation unit. Preferably, the third heat exchanger 10 is a spiral wound tube heat exchanger and is arranged vertically. Further, the inlet at the bottom of the third heat exchanger 10 is connected to the quenching agent feeding device, and the outlet at the top of the third heat exchanger 10 is connected to the quenching reactor 11. The third heat exchanger 10 is used to pre-cool the quenching agent, preferably water, so that it reaches a predetermined temperature before entering the quenching reactor 11, thereby improving the cooling and reaction termination effect on the cyclization reaction liquid.

[0067] The quenching reactor 11 is preferably a dynamic stirred tube reactor, and more preferably a horizontally arranged dynamic stirred tube reactor. The reaction liquid from the cyclization reactor 7 and the quenching agent from the third heat exchanger 10 enter the quenching reactor 11 through the feed inlet, respectively. They continuously contact each other within the quenching reactor 11 and mix rapidly under dynamic stirring, ensuring timely quenching of the cyclization reaction liquid. Since the quenching process is also accompanied by significant exothermic reactions, and insufficient mixing may lead to continued local side reactions, using a dynamic stirred tube reactor as the quenching reactor 11 is beneficial for improving liquid-liquid contact efficiency and heat transfer efficiency, shortening the quenching completion time, and reducing the formation of isomers and tar byproducts.

[0068] The outlet of the quenching reactor 11 is connected to the phase separation unit. The phase separation unit includes an online liquid-liquid phase separator 12, an organic phase receiving device 13, and an aqueous phase receiving device 14. Specifically, the outlet of the quenching reactor 11 is connected to the inlet of the online liquid-liquid phase separator 12, the organic phase outlet of the online liquid-liquid phase separator 12 is connected to the organic phase receiving device 13, and the aqueous phase outlet of the online liquid-liquid phase separator 12 is connected to the aqueous phase receiving device 14. The online liquid-liquid phase separator 12 is used for continuous liquid-liquid separation of the quenched material, separating the system into an organic phase and an aqueous phase. The organic phase mainly contains β-ionone and related organic components and is collected in the organic phase receiving device 13; the aqueous phase is collected in the aqueous phase receiving device 14. The online liquid-liquid phase separator 12 can be a conventional phase separation device suitable for continuous liquid-liquid separation, as long as it can achieve online separation of the organic and aqueous phases.

[0069] The operation process of the production equipment described in this embodiment is as follows: The pseudo-ionone material is stored in the pseudo-ionone feed tank 1 and transported to the first heat exchanger 3 via pipeline under the action of the pseudo-ionone feed pump 2. After pre-cooling, it enters the cyclization reactor 7. The sulfuric acid material is stored in the sulfuric acid feed tank 4 and transported to the second heat exchanger 6 via pipeline under the action of the sulfuric acid feed pump 5. After pre-cooling, it enters the cyclization reactor 7. The two materials are continuously mixed and undergo a cyclization reaction in the cyclization reactor 7 to obtain a reaction solution containing β-ionone. Simultaneously, the quenching agent is stored in the quenching agent feed tank 8 and transported to the third heat exchanger 10 via pipeline under the action of the quenching agent feed pump 9. After pre-cooling, it enters the quenching reactor 11. The reaction solution from the cyclization reactor 7 simultaneously enters the quenching reactor 11, where it rapidly mixes with the pre-cooled quenching agent and completes quenching. The quenched mixture further flows into the online liquid-liquid phase separator 12 to be separated into an organic phase and an aqueous phase. The organic phase enters the organic phase receiving device 13, and the aqueous phase enters the aqueous phase receiving device 14, thereby completing the continuous production of β-ionone.

[0070] In this embodiment, the first heat exchanger 3, the second heat exchanger 6, and the third heat exchanger 10 are preferably all spiral wound tube heat exchangers, and the circulating reactor 7 and the quenching reactor 11 are preferably both dynamically stirred tube reactors. This creates a structural combination of "heat exchanger pre-cooling and continuous reaction in the dynamically stirred tube reactor" in both the circulating and quenching stages. This structural combination facilitates pre-cooling of materials before they enter the reactor and enhances mixing and heat transfer through dynamic stirring within the reactor, thereby improving the control over local temperature rise, reducing side reactions and tar formation, and improving the product quality and continuous operation stability of β-ionone.

[0071] Example 2 This embodiment provides a process for producing β-ionone using the production equipment described in Example 1. The production steps are as follows: (1) Cyclic reaction stage; S1. Mix the pseudoionone (CAS No. 141-10-6) with the organic solvent dichloroethane to prepare a pseudoionone solution with a mass fraction of 5%, and store it in the pseudoionone feed tank 1. Sulfuric acid with a mass fraction of 92% is stored in sulfuric acid feed tank 4; S2. Start the fake ionone feed pump 2 to send the fake ionone solution into the first heat exchanger 3, i.e., the spiral wound tube heat exchanger, for heat exchange and pre-cooling. The fake ionone solution is pre-cooled from 25℃ to -30℃. Start the sulfuric acid feed pump 5 to send sulfuric acid into the second heat exchanger 6, i.e., the spiral wound tube heat exchanger, for heat exchange and pre-cooling. The sulfuric acid is pre-cooled from 25°C to 5°C. The pre-cooled pseudoionone solution and sulfuric acid were fed into the cyclization reactor for reaction. The feed rate of the pseudoionone solution was 15 kg / min, and the feed rate of the sulfuric acid was 0.65 kg / min. The cyclization reactor 7 was a dynamic stirred tube reactor. The internal temperature of the dynamic stirred tube reactor was controlled at -30℃, the liquid holdup was 2.6 kg, the reaction residence time was 10 s, and the discharge rate was 15.65 kg / min. (2) Quenching and phase separation stage; Water is stored in the quenching agent feed tank 8 as the quenching agent. The quenching agent feed pump 9 is turned on to send the water into the third heat exchanger 10, i.e., the spiral wound tube heat exchanger, for pre-cooling to 5°C. The pre-cooled water and the effluent from the cyclic reactor 7 are sent into the quenching reactor 11 for quenching reaction. The rate at which water is sent into the quenching reactor 11 is 0.85 kg / min, and the rate at which the effluent from the cyclic reactor 7 is sent into the quenching reactor 11 is 15.65 kg / min. The quenching reactor 11 is a dynamic stirred tube reactor. The internal temperature of the quenching reactor 11 is controlled at 55°C, the liquid holdup is 16.5 kg, the reaction residence time is 1 min, and the discharge rate is 16.5 kg / min.

[0072] The discharge from the quenching reactor 11 is fed into the online liquid-liquid phase separator 12 at a rate of 16.5 kg / min for phase separation. The internal temperature of the online liquid-liquid phase separator 12 is controlled at 55℃, the liquid holding capacity is 16.5 kg, and the residence time is 1 min. After phase separation, the organic phase is sent to the organic phase receiving device 13, and the aqueous phase is sent to the aqueous phase receiving device 14.

[0073] Example 3 This embodiment provides a process for producing β-ionone using the production equipment described in Example 1. The production steps are as follows: (1) Cyclic reaction stage; S1. Mix pseudoionone (CAS No. 141-10-6) with the organic solvent n-heptane to prepare a pseudoionone solution with a mass fraction of 30% and store it in pseudoionone feed tank 1. Sulfuric acid with a mass fraction of 92% is stored in sulfuric acid feed tank 4; S2. Start the fake ionone feed pump 2 to send the fake ionone solution into the first heat exchanger 3, i.e., the spiral wound tube heat exchanger, for heat exchange and pre-cooling. The fake ionone solution is pre-cooled from 25℃ to -30℃. Start the sulfuric acid feed pump 5 to send sulfuric acid into the second heat exchanger 6, i.e., the spiral wound tube heat exchanger, for heat exchange and pre-cooling. The sulfuric acid is pre-cooled from 25°C to 5°C. The pre-cooled pseudoionone solution and sulfuric acid were fed into the cyclization reactor for reaction. The feed rate of the pseudoionone solution was 10 kg / min, and the feed rate of the sulfuric acid was 2.6 kg / min. The cyclization reactor 7 was a dynamic stirred tube reactor. The internal temperature of the dynamic stirred tube reactor was controlled at -30℃, the liquid holdup was 12.6 kg, the reaction residence time was 1 min, and the discharge rate was 12.6 kg / min. (2) Quenching and phase separation stage; Water is stored in the quenching agent feed tank 8 as the quenching agent. The quenching agent feed pump 9 is turned on to send the water into the third heat exchanger 10, i.e., the spiral wound tube heat exchanger, for pre-cooling to 5°C. The pre-cooled water and the effluent from the cyclic reactor 7 are sent into the quenching reactor 11 for quenching reaction. The rate at which water is sent into the quenching reactor 11 is 3.9 kg / min, and the rate at which the effluent from the cyclic reactor 7 is sent into the quenching reactor 11 is 12.6 kg / min. The quenching reactor 11 is a dynamic stirred tube reactor. The internal temperature of the quenching reactor 11 is controlled at 55°C, the liquid holding capacity is 99 kg, the reaction residence time is 6 min, and the discharge rate is 16.5 kg / min.

[0074] The discharge from the quenching reactor 11 is fed into the online liquid-liquid phase separator 12 at a rate of 16.5 kg / min for phase separation. The internal temperature of the online liquid-liquid phase separator 12 is controlled at 55℃, the liquid holding capacity is 99 kg, and the residence time is 6 min. After phase separation, the organic phase is sent to the organic phase receiving device 13, and the aqueous phase is sent to the aqueous phase receiving device 14.

[0075] Example 4 This embodiment provides a process for producing β-ionone using the production equipment described in Example 1. The production steps are as follows: (1) Cyclic reaction stage; S1. Mix the pseudoionone (CAS No. 141-10-6) with the organic solvent toluene to prepare a pseudoionone solution with a mass fraction of 18%, and store it in the pseudoionone feed tank 1. Sulfuric acid with a mass fraction of 92% is stored in sulfuric acid feed tank 4; S2. Start the fake ionone feed pump 2 to send the fake ionone solution into the first heat exchanger 3, i.e., the spiral wound tube heat exchanger, for heat exchange and pre-cooling. The fake ionone solution is pre-cooled from 25℃ to -30℃. Start the sulfuric acid feed pump 5 to send sulfuric acid into the second heat exchanger 6, i.e., the spiral wound tube heat exchanger, for heat exchange and pre-cooling. The sulfuric acid is pre-cooled from 25°C to 5°C. The pre-cooled pseudoionone solution and sulfuric acid were fed into the cyclization reactor for reaction. The feed rate of the pseudoionone solution was 8 kg / min, and the feed rate of the sulfuric acid was 1.7 kg / min. The cyclization reactor 7 was a dynamic stirred tube reactor. The internal temperature of the dynamic stirred tube reactor was controlled at -30℃, the liquid holdup was 5.82 kg, the reaction residence time was 36 s, and the discharge rate was 9.7 kg / min. (2) Quenching and phase separation stage; Water is stored in the quenching agent feed tank 8 as the quenching agent. The quenching agent feed pump 9 is turned on to send the water into the third heat exchanger 10, i.e., the spiral wound tube heat exchanger, for pre-cooling to 5°C. The pre-cooled water and the effluent from the ring reactor 7 are sent into the quenching reactor 11 for quenching reaction. The rate at which water is sent into the quenching reactor 11 is 3 kg / min, and the rate at which the effluent from the ring reactor 7 is sent into the quenching reactor 11 is 9.7 kg / min. The quenching reactor 11 is a dynamic stirred tube reactor. The internal temperature of the quenching reactor 11 is controlled at 55°C, the liquid holding capacity is 45.7 kg, the reaction residence time is 3.6 min, and the discharge rate is 12.7 kg / min.

[0076] The discharge from the quenching reactor 11 is fed into the online liquid-liquid phase separator 12 at a rate of 12.7 kg / min for phase separation. The internal temperature of the online liquid-liquid phase separator 12 is controlled at 55℃, the liquid holding capacity is 45.7 kg, and the residence time is 3.6 min. After phase separation, the organic phase is sent to the organic phase receiving device 13, and the aqueous phase is sent to the aqueous phase receiving device 14.

[0077] Example 5 The only difference between this embodiment and Embodiment 2 is that the pseudo-ionone solution was pre-cooled from 25°C to -60°C. Pre-cool the sulfuric acid from 25°C to 0°C; Example 6 The only difference between this embodiment and Example 2 is that the pseudo-ionone solution was pre-cooled from 25°C to -50°C. The sulfuric acid was pre-cooled from 25°C to 2°C; Example 7 The only difference between this embodiment and Example 2 is that the pseudo-ionone solution was pre-cooled from 25°C to 0°C; and the sulfuric acid was pre-cooled from 25°C to 10°C. Example 8 The only difference between this embodiment and Embodiment 2 is that the pseudo-ionone solution was pre-cooled from 25°C to 5°C; and the sulfuric acid was pre-cooled from 25°C to 15°C. Example 9 The only difference between this embodiment and Embodiment 2 is that the temperature of the dynamic stirred tubular reactor during the cyclization reaction stage is controlled at -40°C. Example 10 The only difference between this embodiment and Embodiment 2 is that the temperature of the dynamic stirred tubular reactor during the cyclization reaction stage is controlled at -10°C. Example 11 The only difference between this embodiment and Embodiment 2 is that the temperature of the dynamic stirred tubular reactor during the cyclization reaction stage is controlled at 30°C. Example 12 The only difference between this embodiment and Embodiment 2 is that the temperature of the dynamic stirred tubular reactor during the cyclization reaction stage is controlled at 40°C. Example 13 The only difference between this embodiment and Embodiment 2 is that, during the quenching stage, water is sent into the third heat exchanger to pre-cool to 3°C. Example 14 The only difference between this embodiment and Embodiment 2 is that, during the quenching stage, water is sent into the third heat exchanger to pre-cool to 15°C. Example 15 The only difference between this embodiment and embodiment 2 is that the temperature of the quenching reactor 11 is controlled at 25°C; and the temperature of the online liquid-liquid phase separator 12 is controlled at 25°C.

[0078] Example 16 The only difference between this embodiment and embodiment 2 is that the temperature of the quenching reactor 11 is controlled at 70°C; and the temperature of the online liquid-liquid phase separator 12 is controlled at 70°C.

[0079] Comparative Example 1 The difference between this comparative example and Example 2 is that: the first heat exchanger 3, the second heat exchanger 6, and the third heat exchanger 10 are not set; the temperature at which the fake ionone solution and sulfuric acid enter the cyclization reactor is 25°C; and the temperature at which water enters the quenching reactor 11 is 25°C.

[0080] Comparative Example 2 This comparative example uses a microchannel reactor to produce β-ionone, as detailed below: A 5% (w / w) ionone solution was prepared by mixing pseudoionone (CAS No. 141-10-6) with the organic solvent dichloroethane. The -30℃ pseudoionone solution and 5℃ 92% (w / w) sulfuric acid were introduced into the first microchannel reactor through two inlets. The feed rate of the pseudoionone solution into the first microchannel reactor was 0.15 kg / min, and the feed rate of the sulfuric acid was 0.0065 kg / min. The temperature conditions inside the first microchannel reactor were 0℃, the liquid holdup was 0.026 kg, the reaction residence time was 10 s, and the discharge rate was 0.1565 kg / min. Cooling water and the effluent from the first microchannel reactor are fed into the second microchannel reactor. The rate at which water is fed into the second microchannel reactor is 0.0085 kg / min, and the rate at which the effluent from the first microchannel reactor is fed into the second microchannel reactor is 0.1565 kg / min. The temperature of the second microchannel reactor is controlled at 70℃, the liquid holdup is 0.0825 kg, the reaction residence time is 30 s, and the discharge rate is 0.165 kg / min.

[0081] When using a microchannel reactor, due to its small channel size and high requirements for material uniformity and flow stability, the composition and physical properties of the system change rapidly during the reaction and water addition termination process, which can easily lead to the formation of local high viscosity areas or by-product deposition, resulting in channel blockage. Once blockage or abnormal local flow distribution occurs, it can easily cause uneven local temperature distribution, difficulty in reaction control and unstable operation, which is not conducive to continuous production.

[0082] Comparative Example 3 This comparative example uses a reaction vessel to produce β-ionone, as detailed below: The pseudoionone (CAS No. 141-10-6) was mixed with the organic solvent dichloroethane to prepare a pseudoionone solution with a mass fraction of 5%. 15 kg of the pseudoionone solution was added to the reaction vessel, and 92% sulfuric acid was added dropwise to the reaction vessel at a rate of 0.003 kg / min for 3 h. The temperature inside the reaction vessel was maintained at 35 °C during the cyclization process, and the total cyclization reaction time was 4 h.

[0083] After the cyclization reaction was completed, the resulting material was transferred to a quenching reactor. Water was added dropwise to the quenching reactor under stirring conditions to terminate the reaction. The water temperature was 0°C, the dropping rate was 0.005 kg / min, and the dropping time was 5 h. Phase separation was performed 1 hour after the dropping was completed. During the termination process, the temperature inside the quenching reactor was maintained at 80°C. After the termination treatment was completed, the resulting material was sent to a liquid-liquid phase separator for phase separation, separating the organic phase and the aqueous phase. The organic phase was used for subsequent product analysis.

[0084] It should be noted that this comparative example is used to characterize the overall difference between the traditional batch reactor process and the continuous process of this invention. The purpose of the comparison is to reflect the technical effects of different process routes in actual production, rather than to examine the influence of a single variable. Compared to the continuous precooling, reaction, quenching, and phase separation process used in this invention, the reactor, when handling this type of strongly exothermic system, has difficulty removing the heat of reaction in a timely manner, easily forming local high-temperature zones and local high-acid concentration zones. Furthermore, due to the longer overall residence time and the lag in material transfer, side reactions are exacerbated, tar production increases, and the viscosity of the reaction system becomes uneven throughout, thus reducing the purity and yield of the target product.

[0085] Test Example 1 This test case examined the purity, yield, feed conversion rate, α-ionone content, and tar content of the products obtained in the embodiments and comparative examples of the present invention.

[0086] The test methods involved in this test case are as follows: (1) Determination of the weight of crude product The organic layer flowing out is received at the outlet of the phase separator. Dichloroethane is added to the organic layer for dilution, and anhydrous sodium sulfate is added to remove water. After filtration, a filtrate is obtained. The filtrate is then evaporated to remove the solvent and weighed to obtain the weight of the crude product.

[0087] (2) Determination of the purity of β-ionone A small amount of crude product was dissolved in a quantitative amount of acetonitrile to prepare an analytical solution, which was then analyzed by gas chromatography. Based on the chromatographic results, the relative content of each component in the crude product was calculated using the area normalization method, where the relative content of β-ionone was the purity of β-ionone.

[0088] (3) Determination of α-ionone content Using the above gas chromatography detection results, the relative content of α-ionone in the crude product was calculated according to the area normalization method. This relative content is the α-ionone content.

[0089] (4) Calculation of β-ionone yield The actual yield of β-ionone was calculated based on the weight of the crude product and the purity of β-ionone, and then compared with the theoretical yield to obtain the β-ionone yield. The calculation formula is as follows: β-ionone yield = (crude product weight × β-ionone purity) / theoretical yield of β-ionone × 100%; The theoretical yield of β-ionone is calculated based on the molar amount of pseudoionone entering the system and the 1:1 molar conversion relationship between β-ionone and β-ionone.

[0090] (5) Determination of raw material conversion rate The organic layer flowing out of the phase separator is received. Dichloroethane is added to the organic layer for dilution, and anhydrous sodium sulfate is added to remove water. After filtration, the filtrate is collected and a quantitative amount of acetonitrile is added to prepare an analytical solution. Gas chromatography is used for detection. Based on the chromatographic results, the content of unreacted pseudoionone is calculated using the area normalization method, and then the raw material conversion rate is calculated according to the following formula: Raw material conversion rate = (Amount of pseudoionone entering the system per unit time - Amount of unreacted pseudoionone) / Amount of pseudoionone entering the system per unit time × 100%; (6) Evaluation of tar content Tar levels were evaluated visually, combined with a comprehensive assessment of product color, system viscosity, and adhesion or coking on the equipment's inner walls. Product color reflects the degree of side reactions and tar byproduct formation; system viscosity reflects the amount of highly viscous byproducts or tar-like substances in the system; and adhesion to the equipment's inner walls was graded as the proportion of visible tar-like or highly viscous deposits to the total observable area of ​​the corresponding inner wall. Specific evaluation criteria are as follows: Non-sticking to the wall: There are basically no visible tar-like or highly viscous substances adhering to the inner wall of the equipment, and the area of ​​adhesion to the wall is 0. The corresponding evaluation of tar condition is "light color, low viscosity, non-sticking to the wall". A small amount of tar-like or highly viscous material adheres to the inner wall of the equipment. The area of ​​the tar-like material is 20% or less of the total observable area of ​​the corresponding inner wall. The tar condition is evaluated as "light-colored, low-viscosity, and a small amount of tar-like material adheres to the inner wall". Moderate adhesion: There are obvious tar-like or highly viscous substances adhering to the inner wall of the equipment. The area of ​​adhesion accounts for more than 20% but not more than 50% of the total observable area of ​​the corresponding inner wall. The corresponding tar condition is evaluated as "darkening color, increased viscosity, and moderate adhesion". Severe adhesion to the wall: A large amount of tar-like or highly viscous substances are attached to the inner wall of the equipment, and the area of ​​adhesion accounts for more than 50% but not more than 80% of the total observable area of ​​the corresponding inner wall; the corresponding tar condition is evaluated as "black in color, severe adhesion to the wall" or "black in color, black tar on the vessel wall, severe adhesion to the wall". Equipment blockage: There is a large amount of tar deposit or obvious coking on the inner wall of the equipment, resulting in blockage of the flow channel, poor material discharge, or unstable operation of the equipment. The corresponding tar condition is evaluated as "black in color, severely sticking to the wall, and equipment blockage".

[0091] The test results are shown in Table 1 below: Table 1:

[0092] Comparative studies of Examples 2 and 5-8 show that the system can achieve reaction when the pseudo-ionone solution is pre-cooled to -60℃ to 5℃ via a spiral wound tube heat exchanger and the acidic catalyst is pre-cooled to 0℃ to 15℃ via a spiral wound tube heat exchanger. Further comparison shows that when the pre-cooling temperature of the pseudo-ionone solution is controlled at -60℃ to 0℃ and the pre-cooling temperature of the acidic catalyst is controlled at 0℃ to 10℃, the overall purity and yield of β-ionone are higher, the feed conversion rate is higher, and the tar content is better. However, when the pre-cooling temperatures of the pseudo-ionone solution and the acidic catalyst are further increased to 5℃ and 15℃, respectively, the purity, yield, and feed conversion rate of β-ionone all decrease. This indicates that within the aforementioned lower pre-cooling temperature range, it is more beneficial to reduce the exothermic shock at the moment of material contact, suppress side reactions, and improve the formation of the target product.

[0093] Comparative studies of Examples 2 and 9-12 show that temperature control in the dynamic stirred tubular reactor is crucial during the cyclization reaction stage. When the reactor temperature is controlled within the range of -40℃ to 40℃, the system can achieve the reaction. Specifically, when the temperature is controlled within the range of -40℃ to -10℃, the purity and yield of β-ionone are higher, the content of α-ionone is lower, and the system is basically non-sticky to the walls, resulting in a better overall reaction effect. However, when the temperature rises to 30℃ to 40℃, the purity and yield of β-ionone decrease significantly, the content of α-ionone increases, and a small amount of wall adhesion occurs, indicating that higher temperatures are not conducive to suppressing side reactions and tar formation.

[0094] Comparing Comparative Example 1 and Example 2, it can be seen that without the first, second, and third heat exchangers, the materials enter the reactor directly at room temperature, resulting in a greater instantaneous exothermic shock upon material contact and making it more difficult to control the local temperature rise. This leads to a decrease in the purity and yield of β-ionone, an increase in the content of α-ionone, and exacerbates system wall adhesion and tar formation. In contrast, the present invention, by pre-cooling the cyclization raw materials and quenching agent separately and using a dynamic stirred tubular reactor for continuous reaction and quenching, is more conducive to improving the purity and yield of the target product and suppressing the occurrence of side reactions.

[0095] Comparing Example 2 with Comparative Examples 2 and 3, it can be seen that, compared with the problems of microchannel reactors being prone to clogging, uneven local temperature control in the reaction vessel, and aggravated side reactions, the continuous process route of the present invention, which combines a spiral wound tube heat exchanger with a dynamic stirred tube reactor, is more conducive to achieving rapid mixing, timely heat transfer, and stable operation, thereby effectively reducing the generation of tar byproducts and improving the purity and yield of β-ionone.

[0096] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. 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 process for producing β-ionone, characterized in that, Includes the following steps: (1) The pseudo ionone solution and acidic catalyst were pre-cooled by a spiral wound tube heat exchanger and then sent to a dynamic stirred tube reactor for mixing and reaction to obtain a mixed reaction solution; (2) The mixed reaction liquid and the quenching agent pre-cooled by the spiral wound tube heat exchanger are sent into the dynamic stirred tube reactor for quenching, and then the phases are separated to obtain the β-ionone.

2. The production process of β-ionone according to claim 1, characterized in that, The mass fraction of pseudoionone in the pseudoionone solution is 5% to 50%. And / or, the acidic catalyst comprises a sulfuric acid solution with a mass fraction of 88% to 98%.

3. The production process of β-ionone according to claim 2, characterized in that, In step (1), the mass ratio of the pseudo-ionone solution to the acidic catalyst is (3-24):

1.

4. The production process of β-ionone according to claim 3, characterized in that, In step (1), the feed rate of the pseudo-ionone solution into the dynamic stirred tube reactor is 8 kg / min to 15 kg / min; And / or, the sulfuric acid solution is fed into the dynamic stirred tubular reactor at a rate of 0.65 kg / min to 2.6 kg / min.

5. A production process for β-ionone according to any one of claims 1-4, characterized in that, In step (1), the pseudo-ionone solution is pre-cooled to -60℃ to 5℃ using a spiral wound tube heat exchanger; And / or, in step (1), the acidic catalyst is precooled to 0°C to 15°C by a spiral wound tube heat exchanger.

6. The production process of β-ionone according to any one of claims 1-4, characterized in that, In step (1), the temperature conditions of the dynamic stirred tube reactor are controlled to be -40℃ to 40℃; And / or, in step (1), the liquid holding capacity of the dynamic stirred tubular reactor is controlled to be 2 kg to 13 kg; And / or, in step (1), the reaction residence time of the dynamic stirred tubular reactor is controlled to be 5s to 7.5min.

7. A production process for β-ionone according to any one of claims 1-4, characterized in that, In step (2), the temperature conditions inside the dynamic stirred tubular reactor are controlled to be 25℃~70℃.

8. A production process for β-ionone according to any one of claims 1-4, characterized in that, In step (2), the quenching agent is pre-cooled to 3℃~15℃ through a spiral wound tube heat exchanger.

9. A production process for β-ionone according to any one of claims 1-4, characterized in that, In step (2), the liquid holding capacity of the dynamic stirred tube reactor is 16.5 kg to 99 kg; And / or, in step (2), the reaction residence time of the dynamic stirred tubular reactor is 1 min to 10 min.

10. A production process for β-ionone according to any one of claims 1-4, characterized in that, In step (2), the quenched material is fed into an online liquid-liquid phase separator for phase separation, and the temperature conditions for phase separation are controlled at 25℃~70℃.

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