A method for preparing a modified titanium-silicon molecular sieve and a method for preparing oxy-alpha-santonin

Abstract

The application discloses a preparation method of modified titanium-silicon molecular sieve and a preparation method of caryophyllene oxide, and belongs to the technical field of synthesis of perfume compounds. The preparation method comprises the following steps: placing titanium-silicon molecular sieve in an organic acid-alcohol solution for impregnation treatment, carrying out drying treatment after solid-liquid separation, and then carrying out heat activation treatment to obtain modified titanium-silicon molecular sieve; the pH value of the organic acid-alcohol solution is 3-6; the molar ratio of silicon to titanium in the titanium-silicon molecular sieve is 30-50:1; then, the modified titanium-silicon molecular sieve is used as a catalyst, an oxidant is mixed with beta-caryophyllene to carry out an oxidation reaction, and a reaction product is obtained; the reaction product is cooled, then subjected to solid-liquid separation, and the filtrate is subjected to purification treatment, so that the caryophyllene oxide is obtained. The method can realize a high-selectivity epoxidation reaction of beta-caryophyllene, greatly improves the product yield and purity of caryophyllene oxide, simultaneously simplifies a production process, reduces environmental protection pressure and production cost, and is suitable for industrialized and large-scale production.

Description

Technical Field

[0001] This invention relates to a method for preparing modified titanium silicate molecular sieves and a method for preparing caryophyllene oxide, belonging to the field of fragrance compound synthesis technology. Background Technology

[0002] Caryophyllene oxide, also known as epoxidized caryophyllene, is an important sesquiterpene oxygen-containing derivative that is naturally found in the essential oils of plants such as clove, peppermint, and tobacco. It has a unique woody, spicy, and balsamic aroma that is mellow and long-lasting. It also possesses excellent antibacterial, anti-inflammatory, and antioxidant bioactivity and is widely used in the fields of daily chemical fragrance formulation, food flavoring, pharmaceutical intermediates, and tobacco additives. Market demand continues to grow.

[0003] Currently, the industrial preparation of caryophyllene oxide mainly uses natural β-caryophyllene as raw material and employs a chemical oxidation method. Existing mainstream processes often use strong peroxyacids such as performic acid and peracetic acid as oxidants. However, these processes have several drawbacks: First, peroxyacids are unstable, flammable, and explosive, posing extremely high risks during storage and transportation, resulting in poor safety in industrial production. Second, the oxidation reaction has low selectivity, easily leading to over-oxidation and double bond side reactions, generating large amounts of byproducts such as alcohols, ketones, and carboxylic acids, resulting in low product purity and significant difficulties in subsequent separation and purification. Third, the reaction system is highly acidic, corroding production equipment and generating large amounts of acidic wastewater and waste solvents, leading to high environmental treatment costs and failing to meet the requirements of green chemical production. Fourth, traditional processes have low raw material conversion rates and product yields, resulting in poor overall economic efficiency.

[0004] In addition, some existing catalytic oxidation processes use oxidants such as potassium permanganate and ozone, which have problems such as over-oxidation, product carbonization, high equipment investment, and harsh reaction conditions, making it difficult to achieve large-scale industrial production.

[0005] For example, Chinese patent document (publication number CN111217770 A) discloses a method for preparing caryophyllene oxide. This method uses natural caryophyllene as a raw material and sodium carbonate as a catalyst, oxidizing it with prepared peracetic acid to obtain caryophyllene oxide. However, this method limits industrial-scale production and product quality improvement. Specific drawbacks include: First, poor reaction selectivity, numerous byproducts, and low product purity. Second, low raw material conversion rate and product yield, resulting in poor raw material utilization. Third, poor reaction system stability, insufficient process controllability, and poor batch-to-batch stability. Fourth, cumbersome post-processing steps, high energy and material consumption, and poor environmental performance. Fifth, poor adaptability to reaction conditions and low process error tolerance.

[0006] Therefore, developing a method for preparing caryophyllene oxide that is highly selective, produces few byproducts, is safe and environmentally friendly, low in cost, and suitable for industrial mass production has become a research focus for those skilled in the art. Summary of the Invention

[0007] To address the problems existing in the prior art, one of the objectives of this invention is to provide a method for preparing modified titanium-silicon molecular sieves. The modified titanium-silicon molecular sieves prepared by this method have high selectivity and high stability. When used as a catalyst for preparing caryophyllene oxide, it can improve its yield and purity.

[0008] The second objective of this invention is to provide a method for preparing caryophyllene oxide, which can achieve a highly selective epoxidation reaction of β-caryophyllene, significantly improve the product yield and purity of caryophyllene oxide, and at the same time simplify the production process, reduce environmental pressure and production costs, and is suitable for industrial-scale production.

[0009] To achieve the above objectives, a first aspect of the present invention provides a method for preparing caryophyllene oxide, the method comprising:

[0010] (1) The titanium-silicon molecular sieve is immersed in an organic acid-alcohol solution, dried after solid-liquid separation, and then thermally activated to obtain a modified titanium-silicon molecular sieve; the pH value of the organic acid-alcohol solution is 3~6; the silicon-titanium molar ratio in the titanium-silicon molecular sieve is 30~50:1.

[0011] This invention innovatively employs a composite modification and optimization process of organic acid-alcohol solution impregnation and high-temperature thermal activation to modify and optimize titanium-silicon molecular sieves. This process overcomes the limitations of traditional single-solvent modification processes, which suffer from limited modification effects and significant non-framework titanium residues. This process can regulate the micropore structure of the molecular sieve, control the ratio of surface acid-base active centers, and efficiently remove ineffective non-framework titanium species, significantly reducing the probability of ineffective side reactions in the catalytic system. It solves the problems of poor selectivity, easy deactivation, and insufficient stability of existing catalysts. The resulting modified titanium-silicon molecular sieve exhibits high targeted catalytic activity, excellent structural stability, and significant side reaction suppression. Specifically, by adding organic acid as a modifying agent to the alcohol solution, the dual effects of alcohol solvent penetration and weak acid modification are synergistically utilized: on the one hand, the excellent penetration and dissolving properties of alcohol are used to open up locally blocked micropores in the molecular sieve, removing template agent residues left during the molecular sieve crystal preparation process; on the other hand, the gentle etching action of the organic acid... This method removes inactive non-framework titanium species from the surface of molecular sieves, while moderately regulating the strength and distribution of acid-base centers on the molecular sieve support surface. This weakens the catalytic activity of ineffective oxidation reactions, optimizes the pore structure and surface properties of the molecular sieve, and removes the solvent adsorbed inside and on the surface of the molecular sieve pores after impregnation, solid-liquid separation, and drying. This eliminates defects such as powder agglomeration, high-temperature sintering, and active site deactivation caused by residual organic solvents, providing a good foundation for subsequent high-temperature thermal activation to prepare high-performance catalysts. After thermal activation, the pore structure and active site distribution formed by organic acid-alcohol composite modification can be fixed, completing the reconstruction of the crystal structure on the molecular sieve surface and optimizing the coordination structure and dispersion of framework titanium active centers. This synergistic modification method can significantly improve the target reaction selectivity, high-temperature thermal stability, and long-term performance of the catalyst, greatly delaying the catalyst deactivation rate, and finally obtaining a highly selective and highly stable modified titanium-silicon molecular sieve composite catalytic material.

[0012] Furthermore, selecting a molecular sieve framework with a silicon-to-titanium molar ratio of 30-50:1 ensures a uniform distribution and appropriate number of active titanium sites in the framework. This guarantees sufficient active centers for epoxidation catalysis, enabling efficient activation of the oxidant and targeted catalysis of the double bond epoxidation reaction of caryophyllene. Simultaneously, it strictly avoids the formation of non-framework titanium and amorphous titanium impurities, effectively suppressing side reactions such as over-oxidation and isomerization. Furthermore, it maintains the intact and regular crystal channel structure and structural stability of the molecular sieve, exhibiting excellent catalytic activity, reaction selectivity, and cycle stability. If the titanium content in the system is too low and the silicon content is too high (silicon-to-titanium molar ratio > 50:1), the number of active titanium sites in the molecular sieve framework is significantly insufficient, resulting in a lack of effective catalytic centers. This leads to insufficient activation of the oxidant, causing a significant decrease in the oxidation reaction rate and a marked reduction in feed conversion. Incomplete reactions and large amounts of feed residues directly result in low product yields and extremely poor catalytic efficiency, failing to meet the requirements for high-efficiency production. If the silicon content in the system is too low and the titanium content is too high (silicon-to-titanium molar ratio < 30:1), the molecular sieve framework's ability to support titanium atoms reaches its limit. Excess titanium atoms cannot enter the framework, resulting in the formation of large amounts of inert impurities such as non-framework titanium and anatase titanium dioxide. These impurities not only lack catalytic selectivity but also induce strong oxidation side reactions, exacerbating excessive oxidation of raw materials and hydrolysis and decomposition of products, significantly increasing the content of by-products and severely reducing the purity of the target product. At the same time, excessive titanium will destroy the regular pore crystal structure of the molecular sieve, causing a decrease in the crystallinity of the molecular sieve, pore blockage, a sharp deterioration in catalyst stability and reusability, and loss of batch stability, significantly increasing the difficulty of subsequent purification and production costs.

[0013] As a preferred embodiment, the thermal activation treatment method includes: heating to 520-530℃ at a heating rate of 3.5-4℃ / min and holding at that temperature for 4.5-5 hours. Experiments have shown that under this preferred condition, β-caryophyllene exhibits superior conversion rate, resulting in products with higher purity and yield.

[0014] As a preferred embodiment, the amount of organic acid in the organic acid-alcohol solution is controlled to achieve a pH value of 3-6, wherein the organic acid is selected from at least one of citric acid, acetic acid, and propionic acid. Using this preferred organic weak acid can further enhance the catalytic activity of the modified titanium-silicon molecular sieve catalyst for β-caryophyllene, avoiding the use of inorganic acid salts and sulfuric acid, which can damage the molecular sieve crystal framework and release new impurity ions that may remain in the titanium-silicon molecular sieve, particularly in the pores, thus affecting the catalytic effect.

[0015] As a preferred embodiment, the alcohol in the organic acid-alcohol solution is anhydrous ethanol.

[0016] As a preferred method, the titanium-silicon molecular sieve is first dried at 110-120℃ for 4-5 hours, then sieved to obtain titanium-silicon molecular sieves with a particle size of 200-400 mesh, followed by impregnation treatment. The initial drying treatment removes adsorbed free moisture, fine impurities, and trace adsorbed impurities from the pores of the titanium-silicon molecular sieve. Subsequent grading and sieving yields molecular sieve powder with a particle size of 200-400 mesh. This pretreatment effectively purifies the raw material, standardizes the powder particle size, and minimizes the adverse effects of impurities and particle size inconsistencies on subsequent modification and catalytic performance.

[0017] As a preferred embodiment, the mass ratio of the titanium-silicon molecular sieve to the organic acid-alcohol solution is 1:4.5~5.

[0018] As a preferred embodiment, the impregnation treatment is carried out at a temperature of 15~35℃ for 1~3h and a stirring rate of 60~100rpm.

[0019] As a preferred embodiment, the drying process is carried out at a temperature of 115~120℃ for 3.5~4 hours.

[0020] As a preferred embodiment, the entire thermal activation process employs dynamic air purging at a flow rate of 30-60 mL / min. Dynamic purging promptly removes organic residues and impurity gases generated during high-temperature decomposition.

[0021] A second aspect of the present invention is to provide a method for preparing caryophyllene oxide, the method comprising:

[0022] (1) Using modified titanium silicate molecular sieve as a catalyst, the oxidant is mixed with β-caryophyllene to carry out an oxidation reaction to obtain the reactants;

[0023] (2) After cooling the reactants, solid-liquid separation is performed, and the filtrate is purified to obtain the final product;

[0024] The modified titanium-silicon molecular sieve is the modified titanium-silicon molecular sieve prepared by the preparation method described in the first aspect above.

[0025] This invention uses refined β-caryophyllene as raw material, combined with a modified titanium-silicon molecular sieve catalyst, to carry out selective epoxidation under mild liquid phase conditions. By optimizing the catalytic system, controlling the oxidation reaction environment, and simplifying the reaction and post-processing, side reactions are suppressed from the source, significantly improving the conversion rate of caryophyllene and the selectivity and yield of oxidized caryophyllene, ensuring high product purity and batch stability. This invention also simplifies the production process, reduces energy consumption and waste emissions, and is suitable for the needs of industrial-scale and green production.

[0026] As a preferred embodiment, the organic solvent for the oxidation reaction is selected from at least one of dichloromethane, ethyl acetate, and anhydrous ethanol;

[0027] The mass ratio of the organic solvent to β-caryophyllene is 3-6:1. If the mass ratio of the organic solvent to β-caryophyllene is less than 3:1, the reaction solution concentration will be too high, resulting in intense exothermic reactions that are difficult to control and pose a risk of material overflow. If the amount of organic solvent is too high, the reaction concentration will be too low, requiring longer reaction times and increasing energy consumption and costs. The mass ratio of the organic solvent to β-caryophyllene is further preferably 3-5:1, and more preferably 3-4:1.

[0028] As a more preferred option, the organic solvent is dichloromethane or ethyl acetate, and more preferably ethyl acetate.

[0029] As a preferred embodiment, the oxidant is added dropwise, and the oxidation reaction is carried out after the dropwise addition is completed. The total dropwise addition time is 1 to 4 hours.

[0030] As a more preferred option, the dripping time is 1 to 3 hours, and more preferably 2 to 3 hours.

[0031] As a preferred embodiment, the oxidation reaction is carried out at 30-55°C for 4-8 hours. It should be noted that the oxidation reaction time does not include the time for adding the oxidant; the temperature is raised to 30-55°C after the oxidant is completely added for the oxidation reaction.

[0032] As a more preferred embodiment, the oxidation reaction is carried out at 40-45°C for 5-7 hours. A further preferred embodiment is at 43-45°C for 5-6 hours.

[0033] As a preferred embodiment, the oxidation reaction is carried out under a protective atmosphere, which is nitrogen and / or argon. The protective atmosphere is introduced to isolate the oxidation reaction from air.

[0034] As a preferred embodiment, the oxidant is tert-butyl hydroperoxide.

[0035] As a preferred embodiment, the molar ratio of β-caryophyllene to the oxidant is 1:1.1~2. If the molar ratio of β-caryophyllene to tert-butyl hydroperoxide is less than 1:1.1, the oxidation is incomplete and the yield is low; if the molar ratio of β-caryophyllene to tert-butyl hydroperoxide is greater than 1:2, unnecessary costs are added.

[0036] As a more preferred embodiment, the molar ratio of β-caryophyllene to the oxidant is 1:1.5~2. If the amount of oxidant is too low, the oxidation will be incomplete, reducing the yield and conversion rate. It should be noted that in this invention, the amount of β-caryophyllene in the molar ratio of β-caryophyllene to the oxidant is based on pure β-caryophyllene.

[0037] As a preferred embodiment, the amount of the modified titanium silicate molecular sieve is 2% to 5% of the mass of β-caryophyllene.

[0038] As a more preferred embodiment, the amount of the modified titanium silicate molecular sieve is 2% to 4% of the mass of β-caryophyllene, and more preferably 2% to 3%.

[0039] As a preferred embodiment, the purity of the β-caryophyllene is ≥97wt%. More preferably, the purity is ≥98wt%, and even more preferably, it is 98.5wt%.

[0040] As a preferred embodiment, the solid obtained through solid-liquid separation in step (3) is the recovered catalyst. After activation treatment, the recovered catalyst can be recycled 5-8 times without significant attenuation of catalytic activity. The unactivated recovered catalyst exhibits a significant decrease in the number of cycles and catalytic activity.

[0041] As a preferred embodiment, the activation treatment method includes: mixing the recovered catalyst with ethanol at a volume ratio of 1:1 to 2, and washing 1 to 5 times. The volume ratio of the recovered catalyst to ethanol is further preferably 1:1 to 1.8, even more preferably 1:1 to 1.5, and the number of washings is further preferably 2 to 4, even more preferably 2 to 3.

[0042] As a preferred embodiment, the purification process includes: washing the filtrate sequentially with a saturated sodium sulfite aqueous solution and deionized water until neutral, allowing it to stand and separate into layers, taking the organic phase, performing vacuum distillation, collecting the target fraction, and obtaining caryophyllene oxide.

[0043] As a preferred method, the volume ratio of filtrate to saturated sodium sulfite aqueous solution is 1:0.05~0.2. The function of the saturated sodium sulfite aqueous solution is to adjust the pH value and neutralize excess tert-butyl peroxide. If the amount of saturated sodium sulfite aqueous solution is too small, the neutralization will be incomplete; if the amount of saturated sodium sulfite aqueous solution is too large, it will increase unnecessary costs. It should be noted that in the volume ratio of filtrate to saturated sodium sulfite aqueous solution, the volume of sodium sulfite aqueous solution refers to the volume used in a single wash.

[0044] As a preferred method, the washing is performed 2 to 4 times with a saturated sodium sulfite aqueous solution and 2 to 4 times with deionized water.

[0045] It should be noted that this invention does not have any special requirements regarding the ratio of filtrate to deionized water. Any method known in the art can be used, as long as the filtrate is washed until neutral.

[0046] As a preferred embodiment, the vacuum degree of the reduced pressure distillation is 0.08~0.095MPa, and the distillation temperature is 110~135℃.

[0047] As a more preferred embodiment, the vacuum degree of the reduced pressure distillation is 0.085~0.095MPa, and more preferably 0.09~0.095MPa.

[0048] As a preferred embodiment, the reflux ratio of the reduced pressure distillation is 2~5:1, the distillation time is 3~6h, more preferably the reflux ratio is 2~4:1; the distillation time is more preferably 3~5h, and even more preferably 4~5h.

[0049] Compared with the prior art, the present invention has at least the following advantages:

[0050] (1) The reaction selectivity is high and the product quality is excellent. The present invention uses tert-butyl hydrogen peroxide combined with modified titanium silicon molecular sieve catalytic system, which can precisely target the carbon-carbon double bond in β-caryophyllene molecule for selective epoxidation, effectively avoiding side reactions such as over-oxidation and isomerization. The raw material conversion rate can reach 96%, the selectivity of oxidized caryophyllene can reach 95%, and the purity of the finished product can reach more than 99%, which is far superior to the product quality of traditional processes.

[0051] (2) The process is safe and mild, and suitable for industrial production: The entire process adopts low-temperature liquid phase reaction, without the need for high temperature, high pressure, strong acid system. The stability of the oxidant tert-butyl hydroperoxide is far superior to that of traditional peroxy acid. The storage, transportation and production risks are low, and the equipment has no corrosion requirements, which greatly reduces production safety hazards and equipment maintenance costs.

[0052] (3) Green and environmentally friendly with low pollution emissions: The reaction system does not involve strong acids or bases, and the post-treatment only generates a small amount of neutral washing wastewater, which can be simply treated to meet the discharge standards; the catalyst can be recycled and reused without solid waste; the organic solvent recovery rate is ≥92%, which can be recycled and reused, greatly reducing the discharge of three wastes and meeting the green chemical production standards.

[0053] (4) Low production cost and significant economic benefits: high raw material utilization rate, very few by-products, simplifying subsequent purification process; catalyst can be recycled multiple times, solvent can be recycled and reused, overall production energy consumption and material consumption are greatly reduced, and large-scale production has a very high cost performance. Attached Figure Description

[0054] Figure 1This is the GC-MS image of caryophyllene oxide prepared in Example 1. As can be seen from the image, caryophyllene oxide has been successfully prepared. Detailed Implementation

[0055] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0056] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments. Obviously, the embodiments described below are only a part of the embodiments, and all other embodiments obtained by those skilled in the art without creative effort are still within the scope of protection of the present invention.

[0057] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0058] The preparation examples of the present invention are used to prepare modified titanium-silicon molecular sieves.

[0059] Preparation Example 1

[0060] (1) The titanium-silicon molecular sieve (silicon-titanium molar ratio 40:1) was dried at 115℃ for 4.5 hours. After cooling to room temperature, the dried powder was graded and screened to select molecular sieve powder with a particle size of 200-300 mesh. It was then stored in a sealed and light-proof manner for later use.

[0061] (2) The molecular sieve powder obtained in step (1) is impregnated in an acetic acid-anhydrous ethanol solution (the solid-liquid mass ratio is 1:4.8, and the acetic acid content in the acetic acid-anhydrous ethanol solution is adjusted to make the pH value of the solution 4). The impregnation temperature is 25℃, the time is 2.5h, and the stirring speed is 80rpm. After solid-liquid separation, it is dried (the temperature is 120℃, the time is 3.5h). Then, the temperature is raised to 530℃ at a heating rate of 3.8℃ / min, and the thermal activation treatment is carried out for 4.5h (and the entire process from the start of heating is dynamically purged with air at a flow rate of 50mL / min) to obtain modified titanium silicon molecular sieve I.

[0062] Preparation Example 2

[0063] (1) Dry the titanium-silicon molecular sieve (silicon-titanium molar ratio 50:1) at 120℃ for 5 hours. After cooling to room temperature, classify and screen the dried powder to select molecular sieve powder with a particle size of 300-400 mesh. Store it in a sealed and light-proof manner for later use.

[0064] (2) The molecular sieve powder obtained in step (1) is impregnated in an acetic acid-anhydrous ethanol solution (the solid-liquid mass ratio is 1:5, and the acetic acid content in the acetic acid-anhydrous ethanol solution is adjusted to make the pH value of the solution 5). The impregnation temperature is 20℃, the time is 3h, and the stirring speed is 70rpm. After solid-liquid separation, it is dried (the temperature is 120℃, the time is 3.5h). Then, the temperature is raised to 520℃ at a heating rate of 3.5℃ / min, and the thermal activation treatment is carried out for 5h (and the entire process from the start of heating is dynamically purged with air at a flow rate of 40mL / min) to obtain modified titanium silicon molecular sieve II.

[0065] Preparation Example 3

[0066] This preparation example was carried out using a method similar to that of Preparation Example 1, except that the heating rate of the thermal activation treatment was adjusted to 5 °C / min to obtain modified titanium-silicon molecular sieve III.

[0067] Preparation Example 4

[0068] This preparation example was carried out using a method similar to that of Preparation Example 1, except that the temperature of the thermal activation treatment was adjusted to 480°C while the time of the thermal activation treatment remained unchanged, resulting in modified titanium-silicon molecular sieve IV.

[0069] Comparative Preparation Example 1

[0070] This comparative preparation example was carried out using a method similar to that of Preparation Example 1, except that the solution used for impregnation was adjusted to be an equal volume of hydrochloric acid-anhydrous ethanol solution (the pH value of the solution was the same as that of Preparation Example 1), and modified titanium silicon molecular sieve DI was obtained.

[0071] Comparative Preparation Example 2

[0072] This comparative preparation example was carried out using a method similar to that of Preparation Example 1, except that the molar ratio of silicon to titanium in the titanium-silicon molecular sieve was adjusted to 25:1 to obtain the modified titanium-silicon molecular sieve D-II.

[0073] Comparative preparation example 3

[0074] This comparative preparation example was carried out using a method similar to that of Preparation Example 1, except that the impregnation solution was adjusted to an equal volume of anhydrous ethanol solution (the pH value was not adjusted using organic acid), resulting in modified titanium-silicon molecular sieve D-III.

[0075] The embodiments of the present invention are used to prepare caryophyllene oxide.

[0076] Example 1

[0077] (1) Raw material pretreatment

[0078] Add 100g of β-caryophyllene with a purity of 98.5wt% to a dry and clean 1000mL glass reactor, then add 400g of anhydrous ethyl acetate, stir at room temperature for 20min, and mix evenly to obtain a raw material mixture.

[0079] (2) Catalytic oxidation reaction

[0080] Add 3g of modified titanium-silicon molecular sieve I to the mixture and stir at room temperature to disperse it evenly; slowly add 85g of tert-butyl hydrogen peroxide over a period of 2.5h. After the addition is complete, raise the temperature to 44℃ and stir at a constant temperature for 5.5h. During the reaction, a small amount of nitrogen gas is introduced for protection.

[0081] (3) Post-processing separation

[0082] After the reaction was completed, the mixture was allowed to cool naturally to room temperature and the solid catalyst was recovered by filtration. The filtrate (575 mL) was first washed twice with 50 mL of saturated sodium sulfite aqueous solution, and then washed three times with 300 mL of deionized water until the pH of the washing solution was 7. The mixture was allowed to stand and separate into layers, and the upper organic phase was collected.

[0083] (4) Distillation purification

[0084] The organic phase was transferred into a vacuum distillation apparatus, and the vacuum degree was controlled at 0.095 MPa, the distillation temperature at 120 °C, the reflux ratio at 3:1, and the distillation was carried out for 3.5 h. The target fraction was collected to obtain 102.4 g of caryophyllene oxide product.

[0085] The results showed that the β-caryophyllene conversion rate was 96.8%, the product selectivity was 95.6%, the product purity was 99.6%, and the yield was 95%.

[0086] Example 2

[0087] (1) Raw material pretreatment

[0088] Add 100g of β-caryophyllene with a purity of 98.2wt% to a dry and clean 1000mL glass reactor, then add 400g of anhydrous ethyl acetate, stir at room temperature for 10min, and mix evenly to obtain a raw material mixture.

[0089] (2) Catalytic oxidation reaction

[0090] Add 5g of modified titanium-silicon molecular sieve I to the mixture and stir at room temperature to disperse it evenly; slowly add 85g of tert-butyl hydrogen peroxide dropwise over 1.5h. After the addition is complete, raise the temperature to 42℃ and stir at a constant temperature for 6h. During the reaction, a small amount of nitrogen gas is introduced for protection.

[0091] (3) Post-processing separation

[0092] After the reaction was completed, the mixture was allowed to cool naturally to room temperature and the solid catalyst was recovered by filtration. The filtrate (570 mL) was first washed twice with 60 mL of saturated sodium sulfite aqueous solution, and then washed three times with 400 mL of deionized water until the pH of the washing solution was 7. The mixture was allowed to stand and separate into layers, and the upper organic phase was collected.

[0093] (4) Distillation purification

[0094] The organic phase was transferred into a vacuum distillation apparatus, and the vacuum degree was controlled at 0.09 MPa, the distillation temperature at 125 °C, the reflux ratio at 4:1, and the distillation was carried out for 4 hours. The target fraction was collected to obtain 99.7 g of caryophyllene oxide product.

[0095] The results showed that the β-caryophyllene conversion rate was 96.2%, the product selectivity was 95.1%, the product purity was 99.5%, and the yield was 92.5%.

[0096] Example 3

[0097] (1) Raw material pretreatment

[0098] Add 100g of β-caryophyllene with a purity of 97.6wt% to a dry and clean 1000mL glass reactor, then add 300g of anhydrous dichloromethane, stir at room temperature for 15min, and mix evenly to obtain a raw material mixture.

[0099] (2) Catalytic oxidation reaction

[0100] Add 5g of modified titanium-silicon molecular sieve I to the mixture and stir at room temperature to disperse it evenly; slowly add 80g of tert-butyl hydrogen peroxide dropwise over 1.5h. After the addition is complete, raise the temperature to 38℃ and stir at a constant temperature for 8h. During the reaction, a small amount of nitrogen gas is introduced for protection.

[0101] (3) Post-processing separation

[0102] After the reaction was completed, the mixture was allowed to cool naturally to room temperature and the solid catalyst was recovered by filtration. The filtrate (565 mL) was first washed twice with 40 mL of saturated sodium sulfite aqueous solution, and then washed four times with 300 mL of deionized water until the pH of the washing solution was 7. The mixture was allowed to stand and separate into layers, and the upper organic phase was collected.

[0103] (4) Distillation purification

[0104] The organic phase was transferred into a vacuum distillation apparatus, and the vacuum degree was controlled at 0.08 MPa, the distillation temperature at 135℃, the reflux ratio at 2:1, and the distillation was carried out for 6 hours. The target fraction was collected to obtain 94.86 g of caryophyllene oxide product.

[0105] The results showed that the β-caryophyllene conversion rate was 92.5%, the product selectivity was 90.4%, the product purity was 99.2%, and the yield was 88%.

[0106] Example 4

[0107] (1) Raw material pretreatment

[0108] Add 100g of 98wt% pure β-caryophyllene to a dry and clean 1000mL glass reactor, then add 600g of anhydrous ethyl acetate, stir at room temperature for 20min, and mix evenly to obtain the raw material mixture.

[0109] (2) Catalytic oxidation reaction

[0110] Add 5g of modified titanium-silicon molecular sieve I to the mixture and stir at room temperature to disperse it evenly; slowly add 85g of tert-butyl hydrogen peroxide over 3 hours. After the addition is complete, raise the temperature to 50°C and stir at a constant temperature for 5 hours. During the reaction, a small amount of nitrogen gas is introduced for protection.

[0111] (3) Post-processing separation

[0112] After the reaction was completed, the mixture was allowed to cool naturally to room temperature and the solid catalyst was recovered by filtration. The filtrate (560 mL) was first washed three times with 60 mL of saturated sodium sulfite aqueous solution, and then washed three times with 300 mL of deionized water until the pH of the washing solution was 7. The mixture was allowed to stand and separate into layers, and the upper organic phase was collected.

[0113] (4) Distillation purification

[0114] The organic phase was transferred into a vacuum distillation apparatus, and the vacuum degree was controlled at 0.09 MPa, the distillation temperature at 130 °C, the reflux ratio at 3:1, and the distillation was carried out for 3.5 h. The target fraction was collected to obtain 97.02 g of caryophyllene oxide product.

[0115] The results showed that the β-caryophyllene conversion rate was 95%, the product selectivity was 93.2%, the product purity was 99.3%, and the yield was 90%.

[0116] Example 5

[0117] (1) Raw material pretreatment

[0118] Add 100g of 98.5% pure β-caryophyllene to a dry and clean 1000mL glass reactor, then add 500g of anhydrous ethyl acetate, stir at room temperature for 20min, and mix evenly to obtain the raw material mixture.

[0119] (2) Catalytic oxidation reaction

[0120] Add 2g of modified titanium-silicon molecular sieve I to the mixture and stir at room temperature to disperse it evenly; slowly add 60g of tert-butyl hydrogen peroxide over 2 hours. After the addition is complete, raise the temperature to 40℃ and stir at a constant temperature for 8 hours. During the reaction, a small amount of nitrogen gas is introduced for protection.

[0121] (3) Post-processing separation

[0122] After the reaction was completed, the mixture was allowed to cool naturally to room temperature and the solid catalyst was recovered by filtration. The filtrate (640 mL) was first washed four times with 100 mL of saturated sodium sulfite aqueous solution, and then washed three times with 300 mL of deionized water until the pH of the washing solution was 7. The mixture was allowed to stand and separate into layers, and the upper organic phase was collected.

[0123] (4) Distillation purification

[0124] The organic phase was transferred into a vacuum distillation apparatus, and the vacuum degree was controlled at 0.095 MPa, the distillation temperature at 120 °C, the reflux ratio at 5:1, and the distillation was carried out for 6 hours. The target fraction was collected to obtain 86.24 g of caryophyllene oxide product.

[0125] The results showed that the β-caryophyllene conversion rate was 89.9%, the product selectivity was 89.2%, the product purity was 99.0%, and the yield was 85%.

[0126] Example 6

[0127] This embodiment is carried out using a method similar to that of Embodiment 1, except that the modified titanium-silicon molecular sieve I is replaced with an equal mass of modified titanium-silicon molecular sieve II.

[0128] The results showed that the β-caryophyllene conversion rate was 96%, the product selectivity was 95%, the product purity was 99.56%, and the yield was 94.8% in this embodiment.

[0129] Example 7

[0130] This embodiment is carried out using a method similar to that of Embodiment 1, except that the modified titanium-silicon molecular sieve I is replaced with an equal mass of modified titanium-silicon molecular sieve III.

[0131] The results showed that the β-caryophyllene conversion rate was 93.4%, the product selectivity was 92.6%, the product purity was 99.5%, and the yield was 91.4%.

[0132] Example 8

[0133] This embodiment is carried out using a method similar to that of Embodiment 1, except that the modified titanium-silicon molecular sieve I is replaced with an equal mass of modified titanium-silicon molecular sieve IV.

[0134] The results showed that the β-caryophyllene conversion rate was 92.5%, the product selectivity was 91.4%, the product purity was 99.3%, and the yield was 90.5%.

[0135] Comparative Example 1

[0136] This comparative example was conducted using a method similar to that of Example 1, except that the amount of modified titanium-silicon molecular sieve I added in this comparative example was 0g.

[0137] The comparative sample showed a β-caryophyllene conversion rate of 35.5%, a product selectivity of 30.5%, a product purity of 98.8%, and a yield of 22.5%.

[0138] Comparative Example 2

[0139] This comparative example was conducted using a method similar to that of Example 1, except that the modified titanium-silicon molecular sieve I was replaced with an equal mass of modified titanium-silicon molecular sieve DI.

[0140] The comparative sample showed a β-caryophyllene conversion rate of 80.8%, a product selectivity of 78.4%, a product purity of 99%, and a yield of 75.4%.

[0141] Comparative Example 3

[0142] This comparative example was prepared using a method similar to that of Example 1, except that the modified titanium silicon molecular sieve I was adjusted to be the same mass as the molecular sieve powder obtained in step (1) of Preparation Example 1.

[0143] The comparative sample showed a β-caryophyllene conversion rate of 88.2%, a product selectivity of 86.5%, a product purity of 99.1%, and a yield of 85.6%.

[0144] Comparative Example 4

[0145] This comparative example was conducted using a method similar to that of Example 1, except that the modified titanium-silicon molecular sieve I was replaced with an equal mass of modified titanium-silicon molecular sieve D-II.

[0146] The comparative sample showed a β-caryophyllene conversion rate of 75.8%, a product selectivity of 71.2%, a product purity of 96.8%, and a yield of 65.4%.

[0147] Comparative Example 5

[0148] This comparative example was conducted using a method similar to that of Example 1, except that the modified titanium-silicon molecular sieve I was replaced with an equal mass of modified titanium-silicon molecular sieve D-III.

[0149] The comparative sample showed a β-caryophyllene conversion rate of 90.2%, a product selectivity of 89.7%, a product purity of 99.2%, and a yield of 88.7%.

[0150] Comparative Example 6 (Traditional Method)

[0151] (1) Preparation of peracetic acid

[0152] Acetic acid and 34% hydrogen peroxide were mixed at a weight ratio of 1:2 to obtain a mixture. Then, at 20°C, sulfuric acid was added dropwise to the mixture at a weight ratio of 1:0.003 to 60% sulfuric acid. The mixture was mixed evenly and reacted for 18 hours before being set aside for later use.

[0153] (2) Preparation of reaction solution

[0154] Natural caryophyllene, ethyl acetate and sodium bicarbonate were mixed in a weight ratio of 1:5:1 to obtain a mixture. Then, at 22°C, peracetic acid obtained in step (1) was added dropwise to the mixture in a weight ratio of 1:3 between caryophyllene and peracetic acid obtained in step (1). The mixture was mixed evenly and reacted for 3 hours. Then, it was cooled to room temperature to obtain a reaction solution containing oxidized caryophyllene.

[0155] (3) Preparation of the final product

[0156] In step (2), the reaction solution containing caryophyllene oxide is mixed and neutralized three times with a saturated sodium sulfite aqueous solution at a volume ratio of 1:0.5. The separated organic phase is then washed with water at a volume ratio of 1:3, and washed three times. After separating the aqueous layer, the oil phase is concentrated under a pressure of 0.01 MPa and a temperature of 35°C to remove ethyl acetate, yielding crude caryophyllene oxide. The crude caryophyllene oxide is then mixed with 95% ethanol at a weight ratio of 1:2, heated under reflux for 20 minutes, and then cooled to -4°C to crystallize and dry. The resulting white solid is the caryophyllene oxide product of this invention.

[0157] The comparative sample showed a β-caryophyllene conversion rate of 85.4%, a product selectivity of 82.1%, a product purity of 98.7%, and a yield of 82.5%.

[0158] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing modified titanium-silicon molecular sieves, characterized in that: The method includes: The titanium-silicon molecular sieve was impregnated in an organic acid-alcohol solution, then dried after solid-liquid separation, and finally thermally activated to obtain the modified titanium-silicon molecular sieve; the pH value of the organic acid-alcohol solution was 3~6; and the silicon-titanium molar ratio in the titanium-silicon molecular sieve was 30~50:

1.

2. The method for preparing a modified titanium-silicon molecular sieve according to claim 1, characterized in that: The amount of organic acid in the organic acid-alcohol solution is controlled so that the pH value of the organic acid-alcohol solution is 3 to 6, wherein the organic acid is selected from at least one of citric acid, acetic acid and propionic acid; And / or, the alcohol in the organic acid-alcohol solution is anhydrous ethanol.

3. The method for preparing a modified titanium-silicon molecular sieve according to claim 1 or 2, characterized in that: The mass ratio of the titanium-silicon molecular sieve to the organic acid-alcohol solution is 1:4.5~5.

4. The method for preparing a modified titanium-silicon molecular sieve according to claim 1 or 2, characterized in that: The impregnation treatment is carried out at a temperature of 15~35℃ for 1~3 hours and at a stirring rate of 60~100 rpm. And / or, the drying process is carried out at a temperature of 115~120℃ for 3.5~4 hours.

5. The method for preparing a modified titanium-silicon molecular sieve according to claim 1 or 2, characterized in that: The method of thermal activation treatment includes: heating to 520-530℃ at a heating rate of 3.5-4℃ / min, and holding at that temperature for 4.5-5 hours.

6. The method for preparing a modified titanium-silicon molecular sieve according to claim 1 or 2, characterized in that: The entire thermal activation process is carried out by dynamic air purging at a flow rate of 30-60 mL / min.

7. A method for preparing caryophyllene oxide, characterized in that: The method includes: (1) Using modified titanium silicate molecular sieve as a catalyst, the oxidant is mixed with β-caryophyllene to carry out an oxidation reaction to obtain the reactants; (2) After cooling the reactants, solid-liquid separation is performed, and the filtrate is purified to obtain the final product; The modified titanium-silicon molecular sieve is the modified titanium-silicon molecular sieve prepared by the preparation method according to any one of claims 1 to 6.

8. The method for preparing caryophyllene oxide according to claim 7, characterized in that: The organic solvent for the oxidation reaction is selected from at least one of dichloromethane, ethyl acetate, and anhydrous ethanol; The mass ratio of the organic solvent to the β-caryophyllene is 3~6:

1.

9. A method for preparing caryophyllene oxide according to claim 7 or 8, characterized in that: The oxidant is added dropwise, and the oxidation reaction is carried out after the dropwise addition is completed. The total dropwise addition time is 1 to 4 hours. And / or, the oxidation reaction is carried out at 30~55°C for 4~8 hours; And / or, the oxidant is tert-butyl hydroperoxide; And / or, the molar ratio of β-caryophyllene to the oxidant is 1:1.1~2; And / or, the amount of the modified titanium silicate molecular sieve is 2% to 5% of the mass of β-caryophyllene.

10. The method for preparing caryophyllene oxide according to claim 9, characterized in that: The molar ratio of β-caryophyllene to the oxidant is 1:1.5~2.

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