Catalyst for the epoxidation of pinene, process for the preparation of 2,3-epoxypinane

Abstract

This application provides a catalyst for the epoxidation of pinene and a method for preparing 2,3-epoxypinane. The catalyst comprises a peroxypolytungstate quaternary ammonium salt, wherein the peroxypolytungstate quaternary ammonium salt is selected from A3[PW4O] 24 ]、A2[SeW2O 14 ]、A3[AsW4O 24 ]、A3[(OH)SiW3O 18 ] and A2[SW2O 14 One or more of the following, wherein A is an organic quaternary ammonium salt cation with 8 to 24 carbon atoms. This catalyst can significantly improve the reaction rate, conversion and selectivity of α-pinene epoxidation to 2,3-epoxypinene.

Description

Technical Field

[0001] This application relates to the field of catalytic chemistry, specifically to a catalyst for pinene epoxidation and a method for preparing 2,3-epoxypinene. Background Technology

[0002] 2,3-Epoxypine is an important organic synthesis intermediate obtained by epoxidation of α-pinene. It can be used to synthesize many fragrances or fine chemicals with special functions and high prices.

[0003] Currently, the industrial production of 2,3-epoxypine by epoxidation of α-pinene involves a long reaction time and requires the addition of a large amount of inorganic base compounds, which easily generates a large amount of saline wastewater that pollutes the environment. Furthermore, the conversion rate and selectivity of 2,3-epoxypine are relatively low.

[0004] Therefore, it is necessary to improve the conversion rate and selectivity of α-pinene epoxidation to produce 2,3-epoxypinene. Summary of the Invention

[0005] This application provides a catalyst for the epoxidation of pinene and a method for preparing 2,3-epoxypinene, aiming to improve the reaction rate, conversion and selectivity of the epoxidation of α-pinene to produce 2,3-epoxypinene.

[0006] In a first aspect, this application provides a catalyst for the epoxidation of pinene, the catalyst comprising a peroxypolytungstate quaternary ammonium salt selected from A3[PW4O] 24 ]、A2[SeW2O 14 ]、A3[AsW4O 24 ]、A3[(OH)SiW3O 18 ] and A2[SW2O 14 One or more of the following:

[0007] Wherein, A is an organic quaternary ammonium salt cation with 8 to 24 carbon atoms.

[0008] According to this application, a catalyst comprising peroxypolytungstate quaternary ammonium salt is provided, which can be used for the epoxidation of α-pinene to produce 2,3-epoxypinene. It exhibits high catalytic activity, providing highly specific and selective yield of 2,3-epoxypinene. It significantly improves the reaction rate, conversion, and selectivity of the epoxidation of α-pinene to produce 2,3-epoxypinene, achieving a conversion rate of over 95% and a selectivity of over 99.8%. Furthermore, the catalyst is easily recoverable and can be reused, thereby saving production costs.

[0009] In some embodiments of this application, A is an organic quaternary ammonium salt cation with 16 to 21 carbon atoms.

[0010] In some embodiments of the present application, the A is [C 18 H 37 N(CH3)3] + or [C 16 H 36 N] + .

[0011] In some embodiments of the present application, the peroxopolytungstate quaternary ammonium salt is selected from one or more of [C 18 H 37 N(CH3)3]3[PW4O 24 ], [C 18 H 37 N(CH3)3]2[SeW2O 14 ], [C 18 H 37 N(CH3)3]3[AsW4O 24 ], [C 18 H 37 N(CH3)3]3[(OH)SiW3O 18 ], and [C 16 H 36 N]2[SW2O 14 ].

[0012] In some embodiments of the present application, the catalyst further comprises a carrier, and the peroxopolytungstate quaternary ammonium salt is loaded on the carrier.

[0013] Optionally, the carrier is selected from one or more of metal oxides, diatomite, zeolite, activated carbon, and silica gel.

[0014] In a second aspect, the present application provides a method for preparing 2,3- epoxy pinane, comprising the following steps:

[0015] Subjecting α-pinene and an oxidant to an epoxidation reaction in an organic solvent in the presence of a catalytic amount of the catalyst according to any one of the embodiments of the first aspect to obtain 2,3-epoxy pinane.

[0016] According to the present application, the catalyst according to any one of the embodiments of the first aspect is used to catalyze the epoxidation of α-pinene to produce 2,3- epoxy pinane. It can be understood that the method for preparing 2,3-epoxy pinane has the beneficial effects of the first aspect, i.e., has a high reaction rate, conversion rate, and selectivity, and recycling the catalyst can reduce production costs.

[0017] In some embodiments of the present application, the method specifically comprises the following steps:

[0018] S1: dissolving and dispersing a- pinene, a catalyst according to any one of the embodiments of the first aspect, an acid-binding agent in an organic solvent to obtain a mixed solution;

[0019] S2: adding an oxidizing agent dropwise to the mixed solution at a preset reaction temperature to make the a-pinene undergo an epoxidation reaction to obtain 2,3-epoxypinane.

[0020] In some embodiments of the present application, the mass ratio of the a-pinene to the catalyst is 1:0.01-0.5; and / or

[0021] The molar ratio of the a-pinene to the oxidizing agent is 1:1-5.

[0022] In some embodiments of the present application, the organic solvent is selected from one or more of ethyl acetate, dichloroethane, tert-butanol, 1,4-dioxane, acetonitrile; and / or

[0023] The oxidizing agent is hydrogen peroxide and / or peroxyacetic acid; and / or

[0024] The acid-binding agent is one or more of disodium hydrogen phosphate, sodium acetate, sodium carbonate.

[0025] In some embodiments of the present application, the preset reaction temperature is 20-70°C. DETAILED DESCRIPTION

[0026] Each embodiment or implementation in the specification is described in a progressive manner, and each embodiment focuses on the difference from other embodiments.

[0027] In the description of the specification, the description of the terms “one embodiment”, “some embodiments”, “exemplary embodiment”, “example”, “specific example”, or “some examples” means that the specific features, structures, materials or characteristics described in connection with the implementation or example are included in at least one implementation or example of the present application. In the specification, the exemplary description of the above terms does not necessarily refer to the same implementation or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more implementations or examples in a suitable manner.

[0028] Further, the terms "first", "second", etc. are used only for descriptive purposes and do not connote or imply relative importance or a quantity of the indicated technical features. Thus, features defined with "first", "second" etc. can include at least one of the features. In the description of the present application, the meaning of "a plurality" is at least two, for example, two, three, etc., unless otherwise specifically defined. In the description of the present application, "room temperature" has the meaning known in the art, generally refers to a temperature of "15℃ to 35℃", unless otherwise specifically defined.

[0029] As described in the background section above, the current 2,3-epoxypinane production enterprises are small in scale, low in technical level, and backward in production process. The quantity and quality of the produced 2,3-epoxypinane cannot meet the market demand, which brings broad prospects for the research and development of the production process of epoxide compounds and dihydroxyl compounds. However, the oxidation system of sodium carbonate, H2O2, (CH3CO)2O, etc. has the problem of long reaction time and the need to add a large amount of inorganic alkali compounds, so a large amount of salt-containing wastewater is generated during the production process and discharged into the environment. Under the increasing environmental pressure, in order to follow the relevant principles of green chemistry, the oxidation system has gradually withdrawn from the stage of industrial production of epoxide compounds and has been replaced by more environmentally friendly and efficient direct epoxidation process.

[0030] Using a catalyst to efficiently catalyze the epoxidation reaction of α-pinene is considered an effective way to improve the reaction rate, conversion rate and selectivity. Therefore, the inventors found through a large number of experiments that using a catalyst containing a specific type of peroxopolytungstate quaternary ammonium salt can effectively improve the conversion rate and selectivity of the production of 2,3-epoxypinane from the epoxidation of α-pinene.

[0031] It should be noted that, unless otherwise specified, the conversion rate described in the context of the present application refers to the conversion rate of α-pinene, which can be calculated by the following formula: conversion rate = m / (n*M), wherein m represents the mass of the actual product, n is the amount of substance of α-pinene in the raw material, and M is the molar mass of 2,3-epoxypinane; the highest conversion rate is 100%.

[0032] Unless otherwise specified, the selectivity described in this application refers to the selectivity of the α-pinene epoxidation reaction, which can be obtained by calculating the mass fraction of 2,3-epoxypinene in the actual product, with a maximum selectivity of 100%. During the α-pinene epoxidation process to produce 2,3-epoxypinene, 2,3-epoxypinene undergoes isomerization to generate byproducts such as α-borneol and 3-pinene. These byproducts have similar boiling points to 2,3-epoxypinene and are difficult to remove from the product. Therefore, the actual product generally contains a certain amount of byproducts. Qualitative and quantitative analysis of the actual product can be performed using gas chromatography and gas chromatography-mass spectrometry (GC-MS) to calculate the mass fraction of 2,3-epoxypinene in the actual product, which is the selectivity of the α-pinene epoxidation reaction.

[0033] The catalyst for pinene epoxidation and the method for preparing 2,3-epoxypine are described in detail below.

[0034] In a first aspect, this application provides a catalyst for the epoxidation of pinene, the catalyst comprising a peroxypolytungstate quaternary ammonium salt, wherein the peroxypolytungstate quaternary ammonium salt is selected from A3[PW4O] 24 ]、A2[SeW2O 14 ]、A3[AsW4O 24 ]、A3[(OH)SiW3O 18 ] and A2[SW2O 14 One or more of the following:

[0035] Wherein, A is an organic quaternary ammonium salt cation with 8 to 24 carbon atoms.

[0036] According to this application, the inventors discovered through extensive experiments that certain types of peroxypolytungstate quaternary ammonium salts exhibit high catalytic activity for the pinene epoxidation reaction. In peroxypolytungstate quaternary ammonium salts, both the type of peroxypolytungstate anion and the type of organic quaternary ammonium salt cation have a certain influence on the catalytic activity. Specifically, the inventors found that the peroxypolytungstate anion is [PW4O]... 24 ] 3- [SeW2O] 14 ] 2- [AsW4O] 24 ] 3- [(OH)SiW3O] 18 ] 3- or [SW2O] 14 ] 2-and the carbon atom number of the organic quaternary ammonium salt cation is 8-24, the peroxypolytungstate quaternary ammonium salt has extremely high catalytic activity for the epoxidation reaction of α-pinene. For example, the carbon atom number of the organic quaternary ammonium salt can be 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, or 24.

[0037] Therefore, when the catalyst containing the above-mentioned peroxypolytungstate quaternary ammonium salt is used for the production of 2, 3-epoxypinane by the epoxidation of α-pinene, the following beneficial effects can be achieved due to the good catalytic activity:

[0038] (1) The epoxidation reaction rate can be effectively improved, and the production efficiency can be improved. In addition, a lower reaction temperature can be used, which improves safety and saves production costs.

[0039] (2) The epoxidation of α-pinene can be performed using an oxidant that is relatively stable and has a slightly weak oxidizing property. For example, low-concentration hydrogen peroxide can be used as the oxidant, which is stable and environmentally friendly. The use of traditional organic peroxides (such as organic peroxy acids) can be effectively avoided. Organic peroxy acids are prone to explosion and produce a large amount of acidic waste liquid, which causes corrosion of the reaction equipment. In addition, under acidic conditions, the target product 2, 3-epoxypinane is prone to isomerization to generate by-products such as α-borneol aldehyde and 3-pinone. The by-products are difficult to separate from the target product, which reduces the selectivity of the reaction. In addition, in order to avoid the influence of the acidic waste liquid, a large amount of inorganic compound needs to be added to the system, which produces a large amount of salt-containing wastewater, pollutes the environment, and increases production costs. Therefore, the use of the above-mentioned catalyst can avoid the use of organic peroxides, thereby effectively overcoming the above-mentioned problems.

[0040] (3) The conversion rate and selectivity of the reaction system can be effectively improved. It has been found through experiments that under appropriate reaction conditions, the conversion rate and selectivity of the production of 2, 3-epoxypinane by the epoxidation of α-pinene can reach more than 95% and more than 99.8%, respectively, which can effectively reduce production costs.

[0041] (4) The above-mentioned catalyst is easy to recover in the reaction system and has good catalytic stability, and can be recycled multiple times, thereby further reducing production costs.

[0042] In some embodiments of the present application, A is an organic quaternary ammonium salt cation having a carbon atom number of 16-21.

[0043] In the above-mentioned embodiments, as described above, the carbon atom number of the organic quaternary ammonium salt cation of the peroxypolytungstate quaternary ammonium salt has a certain influence on its catalytic activity. It has been found through a large number of experiments that under the same conditions, the catalytic activity of the peroxypolytungstate quaternary ammonium salt is better when the carbon atom number of the organic quaternary ammonium salt cation is 16-21.

[0044] In some embodiments of the present application, A is [C 18 H 37 N(CH3)3] + or [C 16 H 36 N] + .

[0045] In some embodiments described above, the inventors have further found through a large number of experiments that the catalytic activity of the peroxopolytungstate quaternary ammonium salt is not only related to the number of C atoms of the organic quaternary ammonium salt cation, but also related to the specific structure of the organic quaternary ammonium salt cation. Under the same conditions, when the organic quaternary ammonium salt cation is [C 18 H 37 N(CH3)3] + or [C 16 H 36 N] + , the catalytic activity of the peroxopolytungstate quaternary ammonium salt is better.

[0046] In some embodiments of the present application, the peroxopolytungstate quaternary ammonium salt is selected from one or more of [C 18 H 37 N(CH3)3]3[PW4O 24 ], [C 18 H 37 N(CH3)3]2[SeW2O 14 ], [C 18 H 37 N(CH3)3]3[AsW4O 24 ], [C 18 H 37 N(CH3)3]3[(OH)SiW3O 18 ], and [C 16 H 36 N]2[SW2O 14 ].

[0047] In some embodiments described above, several peroxopolytungstate quaternary ammonium salts with high catalytic activity are specifically listed. When a catalyst containing the above peroxopolytungstate quaternary ammonium salt is used for the epoxidation of α-pinene to produce 2,3-epoxypinane, it has high reaction rate, conversion rate and selectivity.

[0048] In some embodiments of the present application, the catalyst further comprises a carrier, and the peroxopolytungstate quaternary ammonium salt is loaded on the carrier.

[0049] Optionally, the carrier is selected from one or more of diatomite, zeolite, activated carbon and silica gel.

[0050] In some of the above embodiments, the catalyst can further comprise a carrier, and the peroxopolytungstate quaternary ammonium salt is loaded on the carrier. It can be understood that the peroxopolytungstate quaternary ammonium salt can be directly added into the reaction system as a catalyst for use, and further, it can be loaded on the carrier and added into the reaction system as a catalyst. The carrier can serve as a skeleton of the peroxopolytungstate quaternary ammonium salt and can stabilize the dispersion of the peroxopolytungstate quaternary ammonium salt, thereby increasing the catalytic activity and catalytic stability of the peroxopolytungstate quaternary ammonium salt. In addition, loading the peroxopolytungstate quaternary ammonium salt on the carrier can facilitate the recycling and reuse of the peroxopolytungstate quaternary ammonium salt, thereby reducing the production cost.

[0051] Further, the carrier can be selected from one or more of diatomite, zeolite, activated carbon, and silica gel. It can be understood that the carrier can stably load the peroxopolytungstate quaternary ammonium salt and does not react with the raw materials and products in the reaction system. Those skilled in the art can select the carrier according to the actual situation.

[0052] In some embodiments of the present application, A3[PW4O 24 ] can be prepared by the following method:

[0053] Concentrated hydrochloric acid is added to sodium tungstate, and then hydrogen peroxide is added to react, and then phosphoric acid is added to obtain a mixed solution. A soluble quaternary ammonium salt containing A is added to the mixed solution to obtain A3[PW4O 24 ]. The A3[PW4O 24 ] obtained by the above method has a high yield.

[0054] In some embodiments of the present application, A2[SeW2O 14 ] can be prepared by the following method:

[0055] Hydrogen peroxide is added to tungstic acid to react, and then selenic acid is added to obtain a mixed solution. A soluble quaternary ammonium salt containing A is added to the mixed solution to obtain A2[SeW2O 14 ]. The A2[SeW2O 14 ] obtained by the above method has a high yield.

[0056] In some embodiments of the present application, A3[AsW4O 24 ] can be prepared by the following method:

[0057] Concentrated hydrochloric acid is added to sodium tungstate, and then hydrogen peroxide is added to react, and then hydrogen sodium arsenate is added to obtain a mixed solution. A soluble quaternary ammonium salt containing A is added to the mixed solution to obtain A3[AsW4O 24 ]. The A3[AsW4O 24 ] obtained by the above method has a high yield.

[0058] In some embodiments of the present application, A3[(OH)SiW3O 18 ] can be prepared by the following method:

[0059] To K8[γ-SiW 10 O 36 ] add hydrogen peroxide reaction mixture; to the mixture, add A containing soluble quaternary ammonium salt, to obtain A3[(OH)SiW3O 18 ] The A3[(OH)SiW3O 18 ] obtained by the above method has a high yield.

[0060] In some embodiments of the present application, A2[SW2O 14 ] can be prepared by the following method:

[0061] To tungstic acid, add hydrogen peroxide reaction mixture; to the mixture, add A containing soluble quaternary ammonium salt, to obtain A2[SW2O 14 ] The A2[SW2O 14 ] obtained by the above method has a high yield.

[0062] It can be understood that A3[PW4O 24 ], A2[SeW2O 14 ], A3[AsW4O 24 ], A3[(OH)SiW3O 18 ] and A2[SW2O 14 ] include but are not limited to the above preparation methods.

[0063] In a second aspect, the present application provides a method for preparing 2,3- epoxy pinane, comprising the following steps:

[0064] In the presence of a catalytic amount of the catalyst according to any one of the embodiments of the first aspect, α-pinene and an oxidant are subjected to epoxidation reaction in an organic solvent to obtain 2,3-epoxy pinane.

[0065] According to the present application, the catalyst of any one of the embodiments of the first aspect is used to catalyze the epoxidation of α-pinene to produce 2,3- epoxy pinane. It can be understood that the method for preparing 2,3-epoxy pinane has the beneficial effects of the first aspect, i.e. high reaction rate, conversion rate and selectivity, and recycling of the catalyst can reduce production cost. Thus, the method is green and environmentally friendly, has low environmental pollution and low energy consumption, is conducive to reducing production cost, and is suitable for industrial production.

[0066] In some embodiments of the present application, the method specifically comprises the following steps:

[0067] S1: Dissolve and disperse α-pinene, a catalyst according to any one of the embodiments of the first aspect, and an acid-binding agent in an organic solvent to obtain a mixture;

[0068] S2: drop the oxidizing agent into the mixed solution at a preset reaction temperature to make the α-pinene undergo epoxidation reaction to obtain 2,3-epoxypinane.

[0069] In some of the above embodiments, the step of preparing 2,3-epoxypinane is specifically limited, in step S1, the α-pinene, the catalyst according to any one of the embodiments of the first aspect, and the acid-binding agent are dissolved and dispersed in the organic solvent, and the oxidizing agent is not directly mixed, and in step S2, the oxidizing agent is added dropwise to make the α-pinene undergo epoxidation reaction. The advantage of this method is that it can avoid the accumulation of a large amount of oxidizing agent in the reaction system, thereby avoiding potential safety hazards; the dropwise addition of the oxidizing agent can also improve the conversion rate and selectivity of the reaction, thereby saving production costs.

[0070] It is worth mentioning that the catalyst according to any one of the embodiments of the first aspect has high catalytic activity, so that although the oxidizing agent is added dropwise, the system still has a fast reaction rate, which is also a beneficial effect brought by the use of the above-mentioned catalyst.

[0071] In some embodiments of the present application, the mass ratio of α-pinene to catalyst is 1:0.01-0.5; and / or

[0072] The molar ratio of α-pinene to oxidizing agent is 1:1-5. For example, the mass ratio of α-pinene to catalyst can be 1:0.01, 1:0.02, 1:0.05, 1:0.1, 1:0.15, 1:0.2, 1:0.25, 1:0.3, 1:0.35, 1:0.4, 1:0.45, 1:0.5 or a range formed by any of the above values; the molar ratio of α-pinene to oxidizing agent is 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5 or a range formed by any of the above values.

[0073] In some of the above embodiments, the mass ratio of α-pinene to catalyst is specifically limited, and because the above-mentioned catalyst has high catalytic activity, a small amount of catalyst can effectively improve the reaction rate, conversion rate and selectivity of the reaction system, and too high a content of the catalyst can lead to an increase in production costs, so the mass ratio of α-pinene to catalyst can be controlled within the range of 1:0.01-0.5.

[0074] The molar ratio of α-pinene to oxidizing agent is also specifically limited, in order to improve the conversion rate of α-pinene, the oxidizing agent in the reaction system can be appropriately excessive, but if the content of the oxidizing agent is too high, it can lead to an increase in reaction by-products, and too much oxidizing agent can also cause certain safety hazards, so the molar ratio of α-pinene to oxidizing agent can be controlled within the range of 1:1-5.

[0075] In some embodiments of the present application, the organic solvent is selected from one or more of ethyl acetate, dichloroethane, tert-butyl alcohol, 1,4-dioxane, acetonitrile; and / or

[0076] The oxidizing agent is hydrogen peroxide and / or peracetic acid; and / or

[0077] The acid-binding agent is one or more of disodium hydrogen phosphate, sodium acetate, sodium carbonate.

[0078] In some embodiments described above, several commonly used organic solvents are specifically listed, and the epoxidation reaction of α-pinene is carried out in the organic solvent. It can be understood that the organic solvent is miscible with α-pinene and does not react with the components in the reaction system. Those skilled in the art can select according to actual needs. As an example, 1,4-dioxane is used as the organic solvent in some embodiments.

[0079] The types of oxidizing agents are also specifically listed, and hydrogen peroxide and peracetic acid are commonly used oxidizing agents in the epoxidation reaction of α-pinene. Due to the good reactivity of the above-mentioned catalyst, hydrogen peroxide with weak oxidizing property can be used as the oxidizing agent. In some embodiments, the oxidizing agent is hydrogen peroxide with a mass concentration of 15% to 35%. As an example, hydrogen peroxide with a mass concentration of 27.5% is used as the oxidizing agent.

[0080] The main role of the acid-binding agent is to neutralize the acid generated in the reaction, so as to avoid the high concentration of hydrogen ions in the reaction system, thereby avoiding the isomerization of 2,3-epoxypinane to generate other by-products that are difficult to separate, and improving the selectivity of the reaction. The above lists several commonly used acid-binding agents to ensure that the hydrogen ion concentration in the system is within a suitable range, and those skilled in the art can select according to actual needs.

[0081] In some embodiments of the present application, the preset reaction temperature is 20 to 70°C. For example, the preset reaction temperature can be 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C or a range formed by any of the above values

[0082] In some embodiments described above, the reaction temperature of the epoxidation reaction of α-pinene is specifically limited. It can be understood that too high or too low temperature will affect the reaction time, conversion rate and selectivity. The inventors have found through a large number of experiments that under the condition of using the above-mentioned catalyst, the conversion rate and selectivity are higher when the preset reaction temperature is 20 to 70°C. As an example, the preset reaction temperature is 60°C.

[0083] In some embodiments of the present application, the time for dropping the oxidizing agent is 1 to 5 hours.

[0084] In some of the above embodiments, the time for dropping the oxidizing agent is specified. It is understood that the dropping time of the oxidizing agent has a certain relationship with the preset reaction temperature. The higher the preset reaction temperature, the shorter the dropping time of the oxidizing agent should be. The lower the preset reaction temperature, the longer the dropping time of the oxidizing agent should be. It is found through experiments that when the preset reaction temperature is 20-70°C, the dropping time of the oxidizing agent can be controlled within 1-5h. As an example, the dropping time of the oxidizing agent is 3h.

[0085] In some embodiments of the present application, step S2 further comprises, after the epoxidation reaction of α-pinene, cooling to room temperature, collecting the organic phase by liquid separation, extracting the water phase with ethyl acetate, filtering to recover the catalyst, collecting the ethyl acetate phase by liquid separation again, mixing the organic phase and the ethyl acetate phase, and rotary evaporation to obtain 2,3-epoxypinane.

[0086] Hereinafter, the embodiments of the present application will be described. The embodiments described below are exemplary and are only used to explain the present application and cannot be understood as a limitation of the present application. If a specific technology or condition is not specified in the embodiments, the technology or condition described in the literature in the art or according to the product manual is used. If the reagent or instrument used is not specified by the manufacturer, it is a conventional product that can be obtained by purchase.

[0087] Example 1

[0088] [C 18 H 37 N(CH3)3]3[PW4O 24 ] was prepared as follows:

[0089] A 2500mL flask with stirring, thermometer and condenser was charged with Na2WO4·2H2O 66g (0.2mol) and dissolved with 400mL of deionized water. After the solution was clear, concentrated HCl 40g (200mmol) was added, and a light yellow precipitate was immediately formed. Then 30% H2O2 170g was added to form a peroxopolytungstate solution, which was cooled to room temperature. Then 85% phosphoric acid 5.76g (50mmol) was added, and the solution was stirred at room temperature for 1h. Then a solution containing 52.2g of octadecyltrimethylammonium chloride (150mmol) in 200mL of tert-butanol was added, and the solution was stirred at room temperature for 30min. The white precipitate was collected by filtration, and then washed with excess deionized water and diethyl ether. The precipitate was dried by suction. The crude product was washed with excess deionized water and anhydrous ethanol, and vacuum dried overnight to obtain [C 18 H 37 N(CH3)3]3[PW4O 24 ] 100.5g, yield 96.3%.

[0090] Example 2

[0091] Preparation of 2,3-epoxypinane:

[0092] A clean 2500 mL beaker was taken and [C 18 H 37 N(CH3)3]3[PW4O 24 ]6.26 g (3 mmol), 4 g (28 mmol) of disodium hydrogen phosphate was taken in the beaker, 500 mL of solvent 1,4-dioxane and 238 mL (1.5 mol) of a-pinene was added to the beaker, the system was stirred at 60 °C for 15 min, then 185 g of 27.5% hydrogen peroxide (1.5 mol) was added dropwise to the solution, the reaction was carried out for 3 h. After the completion of the reaction, the system was cooled to room temperature, the organic phase was collected by liquid-liquid separation, the aqueous phase was extracted with ethyl acetate, the catalyst was collected by filtration, the ethyl acetate phase was again collected by liquid-liquid separation, the organic phase and the ethyl acetate phase were mixed and rotary evaporated to obtain the product 221 g, the conversion was 96.8%.

[0093] Example 3

[0094] [C 18 H 37 N(CH3)3]2[SeW2O 14 ] was prepared:

[0095] In a 2500 mL three-necked flask, 50.0 g (0.2 mol) of H2WO4 and 700 mL of 27.5% H2O2 were added, stirred at 60 °C water bath until a colorless clear solution was obtained, hot suction filtration was carried out, cooled to room temperature, then 4 times 80% H2SeO4 (4.2 mL, 56 mmol) was added. After stirring at room temperature for 1 h, 200 mL of tert-butyl alcohol solution containing 69.6 g of octadecyltrimethylammonium chloride (200 mmol) was added, the solution was stirred at room temperature for 30 min, then the white precipitate was collected by filtration, and then washed with excess deionized water and ethyl ether. The precipitate was suction dried. The crude product was washed with excess deionized water and anhydrous ethanol, and dried in vacuum overnight to obtain [C 18 H 37 N(CH3)3]2[SeW2O 14 ]122.3 g, yield 94.2%.

[0096] Example 4

[0097] Preparation of 2,3-epoxypinane:

[0098] A clean 2500 mL beaker was taken and [C 18 H 37 N(CH3)3]2[SeW2O 143.98 g (3 mmol), 4 g (28 mmol) of disodium hydrogen phosphate were placed in a beaker, 500 mL of solvent 1,4-dioxane and 238 ml (1.5 mol) of a-pinene were added to the beaker, the system was stirred at 60°C for 15 min, then 185 g of 27.5% hydrogen peroxide (1.5 mol) was added dropwise to the solution, the reaction was carried out for 3 h. After the reaction was completed, the system was cooled to room temperature, the organic phase was collected by liquid separation, the aqueous phase was extracted with ethyl acetate, the catalyst was collected by filtration, the ethyl acetate phase was collected by liquid separation again, and the organic phase and the ethyl acetate phase were mixed and rotary evaporated to obtain the product 223 g, with a conversion rate of 97.4%.

[0099] Example 5

[0100] [C 18 H 37 N(CH3)3]3[AsW4O 24 ] was prepared as follows:

[0101] A 2500 mL flask with stirring, thermometer and condenser was charged with Na2WO4·2H2O 66 g (0.2 mol), which was dissolved in 400 mL of deionized water, and then concentrated HC1 40 g (200 mmol) was added, and a light yellow precipitate was immediately formed, then 30% H2O2 170 g was added to form a peroxopolytungstate solution, which was cooled to room temperature, and then 4 times Na2H[AsO4]·7H2O aqueous solution (40 mL, 15.6 g, 50 mmol) was added, and the reaction was stirred at room temperature for 1 h, then a solution containing 52.2 g of octadecyltrimethylammonium chloride (100 mmol) in 200 mL of tert-butanol was added, and the solution was stirred at room temperature for 30 min, and then the white precipitate was collected by filtration, and then washed with excess deionized water and diethyl ether. The precipitate was dried under suction. The crude product was washed with excess deionized water and anhydrous ethanol, and dried in vacuum overnight to obtain the catalyst [C 18 H 37 N(CH3)3]3[AsW4O 24 ] 98.6 g, yield 92.5%.

[0102] Example 6

[0103] Preparation of 2,3-epoxypinane:

[0104] A clean 2500 mL beaker was taken, and [C 18 H 37 N(CH3)3]3[AsW4O 246.4 g (3 mmol), 4 g (28 mmol) of disodium hydrogen phosphate were placed in a beaker, to which 500 mL of solvent 1,4-dioxane and 238 ml (1.5 mol) of a-pinene were added, the system was stirred at 60°C for 15 min, then 185 g of 27.5% hydrogen peroxide (1.5 mol) was added dropwise to the solution, the reaction was carried out for 3 h. After the reaction was completed, the system was cooled to room temperature, the organic phase was collected by liquid-liquid separation, the aqueous phase was extracted with ethyl acetate, the catalyst was collected by filtration, and the ethyl acetate phase was collected by liquid-liquid separation again. The organic phase and the ethyl acetate phase were mixed and rotary evaporated to obtain 219 g of product, with a conversion rate of 95.9%.

[0105] Example 7

[0106] [C 18 H 37 N(CH3)3]3[(OH)SiW3O 18 ] of the following formula:

[0107] A 1000 mL flask with stirring, thermometer and condenser was charged with K8[γ-SiW 10 O 36 ]·12H2O (25 g, 8.5 mmol) was dissolved with 480 mL of 30% H2O2, and the solution was stirred at room temperature for 4 h. Octadecyltrimethylammonium chloride (29.6 g, 85 mmol) was dissolved in 200 mL of tert-butanol, and the mixture was stirred vigorously at 45°C for 4 h. A white flocculent suspension appeared, which was filtered, and the white precipitate was collected by filtration, then washed with excess deionized water and diethyl ether. The precipitate was sucked dry. The crude product was washed with excess deionized water and anhydrous ethanol, and dried in vacuum overnight to obtain [C 18 H 37 N(CH3)3]3[(OH)SiW3O 18 ] 49.6 g, yield 96.1%.

[0108] Example 8

[0109] Preparation of 2,3-epoxypinane:

[0110] A clean 2500 mL beaker was taken, and [C 18 H 37 N(CH3)3]3[(OH)SiW3O 185.5 g (3 mmol), 4 g (28 mmol) of disodium hydrogen phosphate were placed in a beaker, 500 mL of solvent 1, 4-dioxane and 238 mL (1.5 mol) of a-pinene were added to the beaker, the system was stirred at 60°C for 15 min, then 185 g of 27.5% hydrogen peroxide (1.5 mol) was added dropwise to the solution, the reaction was carried out for 3 h. After the reaction was completed, the system was cooled to room temperature, the organic phase was collected by liquid separation, the aqueous phase was extracted with ethyl acetate, the catalyst was collected by filtration, the ethyl acetate phase was collected by liquid separation again, and the organic phase and the ethyl acetate phase were mixed and rotary evaporated to obtain 215.3 g of product, with a conversion rate of 94.3%.

[0111] Example 9

[0112] [C 16 H 36 N]2[SW2O 14 ] was prepared as follows:

[0113] A 2500 mL three-necked flask was charged with 50.0 g (0.2 mol) of H2WO4 and 700 mL of 27.5% H2O2, and stirred to a colorless clear solution on a 60°C water bath, and then filtered hot. After cooling to room temperature, 2 mol / L aqueous H2SO4 solution (8 mL, 70 mmol) was added. After stirring at room temperature for 1 h, a solution containing tetrabutylammonium hydrogen sulfate (67.9 g, 200 mmol) in 200 mL of tert-butanol was added, and the solution was stirred at room temperature for 30 min. The light yellow precipitate was collected by filtration, and then washed with excess deionized water and diethyl ether. The precipitate was dried by suction. The crude product was washed with excess deionized water and anhydrous ethanol, and dried in vacuum overnight to obtain [C 16 H 36 N]2[SW2O 14 ] 98.6 g, yield 88.9%.

[0114] Example 10

[0115] Preparation of 2,3-epoxypinane:

[0116] A clean 2500 mL beaker was weighed with [C 18 H 37 N(CH3)3]3[(OH)SiW3O 18]3.33 g (3 mmol), 4 g (28 mmol) of disodium hydrogen phosphate were placed in a beaker, 500 mL of solvent 1,4-dioxane and 238 mL (1.5 mol) of a-pinene were added to the beaker, the system was stirred at 60°C for 15 min, then 185 g of 27.5% hydrogen peroxide (1.5 mol) was added dropwise to the solution, the reaction was carried out for 3 h. After the end of the reaction, the system was cooled to room temperature, the organic phase was collected by liquid-liquid separation, the aqueous phase was extracted with ethyl acetate, the catalyst was collected by filtration, the ethyl acetate phase was collected again by liquid-liquid separation, the organic phase and the ethyl acetate phase were mixed and rotary evaporated to obtain the product 221.9 g, the conversion rate was 97.2%.

[0117] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing 2,3-epoxypinene, characterized in that, Includes the following steps: In the presence of a catalytic amount of catalyst, α-pinene and an oxidant undergo an epoxidation reaction in an organic solvent to yield 2,3-epoxypinene; the catalyst comprises a peroxypolytungstate quaternary ammonium salt selected from [C]. 18 H 37 N(CH3)3]2[SeW2O 14 ] and [C 18 H 37 N(CH3)3]3[(OH)SiW3O 18 One or two of them.

2. The method according to claim 1, characterized in that, Specifically, the following steps are included: S1: Dissolve and disperse α-pinene, the catalyst, and the acid-binding agent in an organic solvent to obtain a mixture; S2: At a preset reaction temperature, an oxidant is added dropwise to the mixture to cause α-pinene to undergo an epoxidation reaction to obtain 2,3-epoxypinene.

3. The method according to claim 1, characterized in that, The mass ratio of α-pinene to the catalyst is 1:0.01~0.5; and / or The molar ratio of α-pinene to the oxidant is 1:1 to 5.

4. The method according to claim 2, characterized in that, The organic solvent is selected from one or more of ethyl acetate, dichloroethane, tert-butanol, 1,4-dioxane, and acetonitrile; and / or The oxidant is hydrogen peroxide and / or peracetic acid; and / or The acid-binding agent is one or more of disodium hydrogen phosphate, sodium acetate, and sodium carbonate.

5. The method according to claim 4, characterized in that, The preset reaction temperature is 20~70℃.