Synthesis method of limonene epoxidation reaction catalytic material based on light-enzyme synergy

Abstract

The invention relates to a synthesis method of a limonene epoxidation reaction catalytic material based on light-enzyme synergy, which comprises the following steps: 1) preparing an aqueous solution containing zinc nitrate hexahydrate and CALB, and recording the aqueous solution as a solution A; preparing an aqueous solution containing 2-methylimidazole and sodium anthraquinone sulfonate (SAS), and recording the aqueous solution as a solution B; and 2) mixing the solution A and the solution B, reacting at a certain temperature for a certain time, carrying out solid-liquid separation after the reaction is finished, and washing and drying the solid to obtain the product. The catalyst is used for preparing 1, 2-epoxy limonene through limonene epoxidation, the reaction condition is milder, and the reaction efficiency is higher; the limonene conversion rate is as high as 91%, the selectivity of the product 1, 2-epoxy limonene is as high as 95%, the performance is stable, and the pH tolerance is strong.

Description

Technical Field

[0001] This invention belongs to the field of catalytic materials technology, specifically relating to a catalytic material, synthesis method and application of limonene epoxidation reaction based on photo-enzyme synergistic catalysis, and particularly to a catalytic system composed of a photosensitizer with sulfonate groups and zeolite imidazole ester framework materials (ZIFs). Background Technology

[0002] Limonene (also known as limonene) is a monoterpene unsaturated compound widely found in natural plants, second only to pinene in distribution. Limonene is typically collected from discarded citrus peels, making it inexpensive and readily available. Its epoxidized product (1,2-epoxylimonene) is an important pharmaceutical intermediate and precursor for high-end chemicals.

[0003] Transition metal complexes were the earliest catalysts used for the epoxidation of limonene (Appl. Catal., A 373(2010)57-65; Catal. Today, 107-108 (2005) 230-234; Catal. Lett., 120 (2008)320-325, CN114890996B). Although these catalysts have high activity, they are difficult to separate and recover, and are generally expensive. In order to solve the problem of the difficulty in reusing homogeneous catalysts, some researchers have also supported the above-mentioned metal complex catalysts on porous solid supports such as activated carbon, molecular sieves, and alumina (J.Mol. Catal. A: Chem., 426 (2017) 223-237; Chem. Eng. Technol., 41 (2018) 124-133; Mo1.Cata1.443(2017)52-59). This approach solves the catalyst recovery problem, but it still cannot avoid issues such as product contamination caused by metal element loss and decreased catalyst activity. Chemical catalysts remain the mainstream method for limonene epoxidation, but problems such as high temperature requirements and numerous side reactions have not yet been resolved.

[0004] Compared to chemical catalysts, enzymatic epoxidation has attracted widespread attention in recent years due to its mild conditions, high selectivity, and high activity (Appl. Catal. A General. 2010, 373, 57-65; J. Mole. Catal. B Enzymatic. 2013, 96, 52-60; CN118028255A). Among them, Candida antarctica lipase B (CALB) is a promising engineered enzyme due to its complete commercialization. However, the process uses hydrogen peroxide as the oxidant, and problems such as reaction volume expansion and enzyme inactivation caused by traditional fed-batch methods remain unresolved. Furthermore, the enzyme preparation is expensive, and its reuse is a pressing issue. Therefore, designing novel hydrogen peroxide supply methods and enabling the reuse of enzyme preparations is a feasible approach to achieve efficient epoxidation of limonene, with significant practical implications, but it still presents considerable challenges.

[0005] Based on this, this application was developed. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for synthesizing catalytic materials for the epoxidation reaction of limonene based on photo-enzyme synergy. The catalyst prepared by this method is used for the epoxidation of limonene to prepare 1,2-epoxylimonene, with milder reaction conditions and higher reaction efficiency.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A method for synthesizing a photo-enzyme synergistic limonene epoxidation catalyst (SAS-CALB@ZIF-8) includes the following steps: 1) Prepare an aqueous solution containing zinc nitrate hexahydrate and CALB, denoted as solution A; prepare an aqueous solution containing 2-methylimidazolium and sodium anthraquinone sulfonate (SAS), denoted as solution B; 2) Mix solution A and solution B and react them at a certain temperature for a certain time. After the reaction is complete, the solid and liquid are separated. The solid is washed and dried to obtain the product.

[0008] Specifically, in step 1), the mass ratio of zinc nitrate hexahydrate to CALB can be 0.1-20:1. The mass ratio of 2-methylimidazole to SAS can be 1-100:1, preferably 10-45:1.

[0009] Furthermore, the mass ratio of 2-methylimidazole to zinc nitrate hexahydrate is 1-20:1.

[0010] Furthermore, the zinc nitrate hexahydrate aqueous solution can be thoroughly mixed with CALB to obtain solution A; and the anthraquinone sulfonate sodium SAS can be thoroughly mixed with the 2-methylimidazole aqueous solution to obtain solution B. Preferably, the concentration of the zinc nitrate hexahydrate aqueous solution can be 0.1-4 mol / L, and the concentration of the 2-methylimidazole aqueous solution can be 0.1-4 mol / L.

[0011] Specifically, in step 2), the reaction temperature is 15-50℃ and the reaction time is 0.5-24 h.

[0012] This invention provides a photo-enzyme synergistic catalytic material for the epoxidation of limonene synthesized by the above-mentioned synthesis method, namely, sodium anthraquinone sulfonate (SAS), CALB, and zeolite imidazole framework-8 (ZIF-8) composite catalyst SAS-CALB@ZIF-8 (SCZ).

[0013] This invention also provides the application of the above-mentioned photo-enzyme synergistic limonene epoxidation catalytic material in the selective oxidation of limonene to 1,2-epoxylimonene.

[0014] Specifically, in the above application, the limonene epoxidation reaction catalytic material (SCZ) based on photo-enzyme synergy is used as the catalyst, oxygen-saturated water / isopropanol is used as the mixed solvent, ethyl acetate is used as the acyl donor, and limonene is used as the raw material. The product 1,2-epoxylimonene is obtained by reacting at a temperature of 15-50℃ under light conditions for 1-12 h.

[0015] Furthermore, the amount of catalyst used is 1-20 wt% of the mass of limonene. The molar ratio of ethyl acetate to limonene is 1-30:1.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The catalyst of the present invention generates hydrogen peroxide under light conditions, which is then supplied to CALB to catalyze the epoxidation reaction; there are currently no reports on photo-enzyme cascade catalysis of limonene epoxidation.

[0017] (2) The present invention has mild catalytic conditions and can convert limonene into 1,2-epoxylimonene with high activity at low temperature and normal pressure. The conversion rate of limonene is as high as 91%, the selectivity of the product 1,2-epoxylimonene is as high as 95%, and the performance is stable and has strong pH tolerance. Attached Figure Description

[0018] Figure 1 The X-ray diffraction pattern of the SCZ catalyst prepared in Example 1 of this invention; Figure 2 This is a scanning electron microscope image of the SCZ catalyst prepared in Example 1 of the present invention; Figure 3This is a transmission electron microscope image of the SCZ catalyst prepared in Example 1 of the present invention; Figure 4 The HAADF diagram and elemental distribution diagrams of S, N, and Zn of the SCZ catalyst prepared in Example 1 of this invention are shown below. Figure 5 This is a scanning electron microscope image of the SCZ catalyst prepared in Example 2 of the present invention; Figure 6 This is a scanning electron microscope image of the SCZ catalyst prepared in Example 3 of the present invention. Detailed Implementation

[0019] The technical solution of the present invention will be further described in detail below with reference to the embodiments, but the scope of protection of the present invention is not limited thereto.

[0020] In the following examples, all raw materials used are common commercially available products that can be purchased directly, or can be prepared using conventional techniques in the art.

[0021] Room temperature refers to 25±5℃.

[0022] Example 1 A method for synthesizing a photo-enzyme synergistic limonene epoxidation catalyst (SAS-CALB@ZIF-8) includes the following steps: 1) Take 0.2 mL (200 mg) of CALB and add it to 2 mL of zinc nitrate hexahydrate aqueous solution (0.3 mol / L, 178.2 mg). After mixing and dissolving thoroughly, we get mixture A; Weigh 50 mg of SAS and add it to 10 mL of 2-methylimidazole aqueous solution (1.25 mol / L, 1025 mg). After mixing and dissolving thoroughly, we get mixture B. 2) Pour mixture A into mixture B, stir and react at 25°C for 12 hours. After the reaction is complete, centrifuge to collect the solid, wash it 3 times with phosphate buffer (pH = 7, 50 mM), and then freeze dry at -40°C for 12 hours to obtain catalyst SCZ.

[0023] The prepared catalyst SCZ was used for the selective oxidation of limonene, specifically as follows: Eight mg of catalyst SCZ was dispersed in 2.45 mL of oxygen-saturated phosphate buffer (pH = 7, 50 mM). One mL of isopropanol, 0.5 mL (5.12 mmol) of ethyl acetate, and 0.05 mL (0.31 mmol, 0.0422 g) of limonene were added. After sealing, the mixture was irradiated at room temperature with a 20 W white LED light. After 6 h of irradiation, gas chromatography showed a limonene conversion of 91% and a 1,2-epoxylimonene selectivity of 95%.

[0024] In addition, to test the catalyst's recyclability, the reacted catalyst was collected by centrifugation, washed three times with phosphate buffer, and then redispersed in the reaction solution for cycling tests. The results showed that the catalyst's activity and selectivity did not significantly decrease within five cycles.

[0025] Figure 1 The image shows the X-ray diffraction pattern of the SCZ catalyst prepared in this embodiment. As can be seen from the image, the obtained catalyst has the same diffraction peak positions as ZIF-8, retaining the crystal structure of ZIF-8.

[0026] Figure 2 The image shows a scanning electron microscope (SEM) image of the SCZ catalyst prepared in this embodiment. As can be seen from the image, the obtained SCZ catalyst is cubic in shape, with a size of approximately 50-300 nm.

[0027] Figure 3 This is a transmission electron microscope image of the SCZ catalyst prepared in this embodiment. The image shows that the catalyst has a cubic structure with irregular pores.

[0028] Figure 4 The figures show the HAADF diagram and elemental distribution diagrams of the SCZ catalyst prepared in this embodiment. It can be seen from the figures that the elements are uniformly distributed within the catalyst.

[0029] Example 2 Referring to Example 1, the difference is that the amount of SAS added is 75 mg. Under the same reaction conditions, the conversion rate of limonene is 85%, and the selectivity for 1,2-epoxylimonene is 91%.

[0030] Figure 5 The image shows a scanning electron microscope (SEM) image of the SCZ catalyst prepared in this embodiment. As can be seen from the image, the obtained SCZ catalyst is cubic in shape, with a size of approximately 50-200 nm.

[0031] Example 3 Referring to Example 1, the difference is that the amount of SAS added is 25 mg. Under the same reaction conditions, the conversion rate of limonene is 50%, and the selectivity for 1,2-epoxylimonene is 90%.

[0032] Figure 6 The image shows a scanning electron microscope (SEM) image of the SCZ catalyst prepared in this embodiment. It can be seen from the image that the obtained SCZ catalyst exhibits poor regularity, with a size of approximately 50-200 nm.

[0033] Example 4 Referring to Example 1, the difference is that the amount of isopropanol used in the catalytic reaction was 2 mL, and the volume of phosphate buffer was 1.35 mL. Under the same reaction conditions, the conversion rate of limonene was 75%, and the selectivity for 1,2-epoxylimonene was 85%.

[0034] Example 5 Referring to Example 1, the difference is that the amount of limonene used in the catalytic reaction was 0.1 mL, and the volume of phosphate buffer was 2.3 mL. Under the same reaction conditions, the conversion rate of limonene was 50%, and the selectivity for 1,2-epoxylimonene was 86%.

Claims

1. A method for synthesizing a limonene epoxidation reaction catalytic material based on light-enzyme synergy, characterized by, Comprising the following steps: 1) preparing an aqueous solution containing zinc nitrate hexahydrate and CALB, denoted as solution A; preparing an aqueous solution containing 2-methylimidazole and sodium anthraquinone sulfonate SAS, denoted as solution B; 2) mixing solution A and solution B and reacting at a certain temperature for a certain time, then separating the solid from the liquid after the reaction, and washing and drying the solid to obtain the product.

2. The synthesis method of limonene epoxidation reaction catalytic material based on light-enzyme cooperation according to claim 1, wherein, In step 1), the mass ratio of zinc nitrate hexahydrate to CALB is 0.1-20:

1.

3. The method for synthesizing a catalytic material based on light-enzyme synergy for limonene epoxidation reaction according to claim 1, wherein, In step 1), the mass ratio of 2-methylimidazole to SAS is 1-100:

1.

4. The method for synthesizing a catalytic material based on photo-enzyme synergy for limonene epoxidation reaction according to claim 1, wherein, In step 1), the mass ratio of 2-methylimidazole to zinc nitrate hexahydrate is 1-20:

1.

5. The method for synthesizing a catalytic material based on photo-enzyme synergy for limonene epoxidation reaction according to claim 1, wherein, In step 2), the reaction temperature is 15-50℃, and the reaction time is 0.5-24 h.

6. The limonene epoxidation reaction catalytic material based on light-enzyme synergy synthesized by the method of any one of claims 1 to 5.

7. The use of the limonene epoxidation reaction catalytic material based on light-enzyme synergy of claim 6 in the selective oxidation of limonene to 1,2-epoxylimonene.

8. Use according to claim 7, wherein the compound is ###0002### The product 1,2-epoxylimonene is prepared by using the limonene epoxidation reaction catalytic material based on light-enzyme synergy of claim 6 as the catalyst, oxygen-saturated phosphate buffer-isopropyl alcohol as the mixed solvent, ethyl acetate as the acyl donor, and limonene as the raw material, under the conditions of temperature 15-50℃ and light irradiation for 1-12 h.

9. Use according to claim 8, wherein the compound is ###0002### The amount of the catalyst is 1-20 wt% of the mass of limonene.

10. The use according to claim 8, wherein the compound is ###00003### or a pharmaceutically acceptable salt thereof. The molar ratio of ethyl acetate to limonene is 1-30:1.

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