A catalyst for the oxidation of 3-oxetane to 3-oxetane, its preparation method, and its application.

Abstract

This invention discloses a catalyst for the oxidation of 3-oxetane to 3-oxetane, its preparation method, and its application. The method uses an Al₂O₃-supported metal composite oxide (CuO-Fe₂O₃-MnO₂ / Al₂O₃) as the catalyst, with CuO content ranging from 1% to 10% by mass; Fe₂O₃ content ranging from 0.5% to 2% by mass; and MnO₂ content ranging from 0.5% to 2% by mass. The application includes the following steps: 3-oxetane is oxidized with oxygen, air, or hydrogen peroxide in the presence of a solvent and the catalyst to obtain 3-oxetane. The method features mild reaction conditions, high product yield, is environmentally friendly, and the catalyst can be recycled and reused.

Description

Technical Field

[0001] This invention belongs to the field of fine chemical technology, specifically relating to a catalyst for the oxidation of 3-oxetane to 3-oxetane, its preparation method, and its application. Background Technology

[0002] 3-Oxycyclic methyl ketone (3-oxetane) is an important pharmaceutical intermediate and a crucial synthetic component in medicinal chemistry. It can be used in the synthesis of various drugs to improve their solubility, lipid solubility, and stability. 3-Oxetane is the most fundamental intermediate in the oxetane system and can be used to derive a variety of downstream products, demonstrating excellent application prospects.

[0003] Currently, there are three main methods for synthesizing 3-oxetane:

[0004] (1) Method 1: Diazomethane and chloroacetyl chloride are used as raw materials to react and obtain diazonone. Diazoone is hydrolyzed and cyclically closed under alkaline conditions to obtain 3-oxetane.

[0005]

[0006] (2) Method 2: Using 1,3-dichloropropanone as the starting material, hydrolyze and circulate it in the presence of sodium methoxide, and finally hydrolyze it under acidic conditions to obtain 3-oxetane.

[0007]

[0008] (3) Method 3: Using 3-oxetanebutanol as a raw material, 3-oxetanebutanone is obtained in the presence of an oxidant.

[0009]

[0010] The above method one uses diazomethane, which is an explosive, flammable, highly toxic, and strongly irritating substance. Therefore, this method poses a significant safety hazard and is not suitable for large-scale production.

[0011] Method 2 above uses 1,3-dichloropropanone as a starting material. 1,3-dichloropropanone is a type of chemical that is highly irritating. Purchasing and using it carries significant risks and is not suitable for large-scale production.

[0012] The above-mentioned method three is the shortest route for the production of 3-oxacyclobutanone. Among them, there are currently three main oxidation systems: (1) phosphorus pentoxide / DMSO system (CN109422709A); ​​(2) PCC / PDC oxidation system (J.org.Chem.1983,48,2953); (3) brominated succinimide, chlorosuccinimide, halide metal salt, alkaline oxidation system (CN103694201A). The phosphorus pentoxide / DMSO system will generate a large amount of phosphorus-containing wastewater, and DMSO is miscible with water, making it difficult to recycle and reuse; the PCC / PDC oxidation system uses chromium trioxide, generating a large amount of chromium-containing wastewater, which puts great pressure on the environment; the brominated succinimide, chlorosuccinimide, halide metal salt, alkaline oxidation system will generate a large amount of solid waste, which also faces environmental pressure. Summary of the Invention

[0013] One objective of this invention is to provide a supported catalyst (abbreviated as CuO-Fe2O3-MnO2 / Al2O3) with Al2O3 as the support and CuO, Fe2O3, and MnO2 as the active components, which exhibits high catalytic activity. A second objective is to provide a method for preparing this catalyst. A third objective is to provide an application of this catalyst for the efficient oxidation of 3-oxetanebutanol to 3-oxetanebutanone using air, oxygen, or hydrogen peroxide.

[0014] This invention is achieved through the following technical solution:

[0015] On one hand, the present invention provides a catalyst for the oxidation of 3-oxetane to 3-oxetane, wherein the active components of the catalyst are CuO, Fe2O3, and MnO2, and the support is Al2O3. The mass content of the active components CuO is 1% to 10%, the mass content of Fe2O3 is 0.5% to 2%, the mass content of MnO2 is 0.5% to 2%, and the Al2O3 is of α, β, or γ type, with the γ type being the most preferred.

[0016] On the other hand, the present invention also provides a method for preparing the catalyst, the specific steps of which are as follows:

[0017] (1) Weigh a certain amount of Cu(NO3)2·3H2O, Fe(NO3)3·9H2O, and Mn(NO3)2 50% aqueous solution and dissolve them in deionized water to prepare solution A, in which the total concentration of metal ions is 0.1~1mol / L;

[0018] (2) Weigh a certain amount of carbonate and dissolve it in deionized water to prepare precipitant solution B, with a carbonate concentration of 0.1~0.5 mol / L;

[0019] (3) Weigh a certain amount of Al2O3 and polyethylene glycol (PEG), disperse them in deionized water to prepare solution C, wherein the concentration of Al2O3 is 100 g / L and the concentration of polyethylene glycol is 0.01 mol / L;

[0020] (4) Stir and heat solution C to 70°C. Add solution A and solution B dropwise to solution C simultaneously and in parallel, controlling the final pH to 7~8. After the addition is complete, keep warm and age for 2 hours. Then cool down and filter, wash with deionized water, dry the filter cake at 100°C for 2 hours, and then calcine at 300~500°C for 2 hours to obtain the catalyst.

[0021] In step (2), the carbonate is one of Na2CO3, K2CO3, and (NH4)2CO3, and the polyethylene glycol is one of PEG2000 and PEG4000.

[0022] The catalyst can also be prepared by the forward and reverse addition methods in the co-precipitation process. The catalyst prepared by the co-flow method provided by the present invention has a more uniform loading of active components and higher catalytic activity.

[0023] The catalyst preparation principle provided by this invention is as follows: Cu(NO3)2·3H2O, Fe(NO3)3·9H2O, and Mn(NO3)2 react with the precipitant carbonate to generate Cu(CO3)2, Fe2(CO3)3, and Mn(CO3)2. After drying and calcination, CuO, Fe2O3, and MnO2 are generated. The addition of polyethylene glycol makes the active components more uniformly deposited on the surface of the support.

[0024] On the other hand, the present invention also provides the application of the catalyst in the oxidation of 3-oxetane to 3-oxetane. The catalyst is added to a mixture of 3-oxetane and an organic solvent, and an oxidant is introduced or added dropwise at a certain temperature to carry out the oxidation reaction. After the reaction is completed, solid-liquid separation is performed, and the liquid portion is purified to obtain 3-oxetane. The reaction conditions are as follows:

[0025] (1) The amount of catalyst used is 1-10 wt% of 3-oxetanebutanol;

[0026] (2) The molar ratio of the oxidant to 3-oxetanebutanol is 1~1.5:1;

[0027] (3) The oxidation reaction temperature is 0~100℃.

[0028] When the catalyst provided by this invention is used to oxidize 3-oxetanebutanol to 3-oxetanebutanone, the oxidant can be air, oxygen, or hydrogen peroxide. When air or oxygen is used as the oxidant, air or oxygen is bubbled into the reaction system consisting of 3-oxetanebutanol, solvent, and catalyst, and the bubbling rate is not specifically limited. When hydrogen peroxide is used as the oxidant, hydrogen peroxide is added to the reaction system dropwise.

[0029] The organic solvent used in the oxidation of 3-oxetane to 3-oxetane is one or more of the following: acetone, dichloromethane, trichloromethane, dichloroethane, tetrachloroethane, tetrahydrofuran, ethyl acetate, n-hexane, and cyclohexane.

[0030] After the oxidation reaction is completed, solid-liquid filtration separation is performed, the catalyst is recovered and reused, and the mother liquor is purified by distillation to obtain 3-oxetane.

[0031] Compared with the prior art, the present invention has the following outstanding effects: using the CuO-Fe2O3-MnO2 / Al2O3 catalyst provided by the present invention, the conversion rate of the raw material 3-oxetanebutanol can reach more than 99%, and it is almost completely oxidized to 3-oxetanebutanone without side reactions. The product yield can reach 84-86%. The catalyst can be recovered and its catalytic activity can remain stable after repeated reuse. Using air, oxygen or hydrogen peroxide as oxidant, no other waste is generated except for water. The process is clean and environmentally friendly. Implementation

[0032] The present invention will be described in more detail below through specific embodiments; the embodiments are merely illustrative of the present invention and do not constitute a limitation thereof. Example

[0033] Preparation of catalysts:

[0034] 30g of Cu(NO3)2·3H2O, 4g of Fe(NO3)3·9H2O, and 2.5g of a 50% aqueous solution of Mn(NO3)2 were dissolved in 1000g of deionized water to prepare solution A. 16g of Na2CO3 was dissolved in 1000g of deionized water to prepare solution B. 100g of γ-Al2O3 and 20g of PEG2000 were dispersed in 1000g of deionized water to prepare solution C. Solution C was stirred and heated to 70℃. Solutions A and B were simultaneously added dropwise to solution C, controlling the final pH to 7-8. After the addition was complete, the reaction was maintained at 70℃ for 2 hours. The mixture was then cooled to room temperature and filtered. The filter cake was washed with deionized water, dried at 100℃ for 2 hours, and then calcined at 400℃ for 2 hours to obtain CuO-Fe2O3-MnO2 / Al2O3 catalyst #1.

[0035] Preparation of 3-oxetane:

[0036] 200g of dichloromethane, 74g of 3-oxetane, and 5g of catalyst #1 were added to a reaction flask. The temperature was controlled at 10~20℃, and oxygen was bubbled through. After the reaction was completed, gas chromatography analysis showed that the conversion rate of the 3-oxetane was 99.8%. The reaction solution was filtered, and the catalyst was washed with dichloromethane. The catalyst washing solution was combined with the reaction solution, and most of the solvent dichloromethane was removed by atmospheric distillation. Then, 3-oxetane was obtained by vacuum distillation with a yield of 85.6% and a purity of 99.6%. Example

[0037] Preparation of catalysts:

[0038] 8g of Cu(NO3)2·3H2O, 2g of Fe(NO3)3·9H2O, and 6g of 50% aqueous solution of Mn(NO3)2 were dissolved in 1000g of deionized water to prepare solution A; 7g of Na2CO3 was dissolved in 500g of deionized water to prepare solution B; 100g of γ-Al2O3 and 20g of PEG2000 were dispersed in 1000g of deionized water to prepare solution C; solution C was stirred and heated to 70℃, and solutions A and B were simultaneously added dropwise to solution C, controlling the final pH to 7~8. After the addition was complete, the reaction was kept at 70℃ for 2h, cooled to room temperature, filtered, the filter cake was washed with deionized water, dried at 100℃ for 2h, and then calcined at 450℃ for 2h to obtain CuO-Fe2O3-MnO2 / Al2O3 2# catalyst.

[0039] Preparation of 3-oxetane:

[0040] 200g of dichloromethane, 74g of 3-oxetane, and 3g of catalyst #2 were added to the reaction flask. The temperature was controlled at 10~20℃, and air was bubbled through. After the reaction was completed, gas chromatography analysis showed that the conversion rate of the 3-oxetane was 99.6%. The reaction solution was filtered, and the catalyst was washed with dichloromethane. The catalyst washing solution was combined with the reaction solution, and most of the solvent dichloromethane was removed by atmospheric distillation. Then, 3-oxetane was obtained by vacuum distillation with a yield of 84.1% and a purity of 99.5%. Example

[0041] Preparation of catalysts:

[0042] 16g of Cu(NO3)2·3H2O, 5g of Fe(NO3)3·9H2O, and 4g of a 50% aqueous solution of Mn(NO3)2 were dissolved in 1000g of deionized water to prepare solution A. 10g of (NH4)2CO3 was dissolved in 1000g of deionized water to prepare solution B. 100g of γ-Al2O3 and 40g of PEG2000 were dispersed in 1000g of deionized water to prepare solution C. Solution C was stirred and heated to 70℃. Solutions A and B were simultaneously added dropwise to solution C, controlling the final pH to 7-8. After the addition was complete, the reaction was maintained at 70℃ for 2 hours. The mixture was then cooled to room temperature and filtered. The filter cake was washed with deionized water, dried at 100℃ for 2 hours, and then calcined at 400℃ for 2 hours to obtain CuO-Fe2O3-MnO2 / Al2O3 catalyst #3.

[0043] Preparation of 3-oxetane:

[0044] 200g of dichloroethane, 74g of 3-oxetane, and 7g of catalyst #3 were added to a reaction flask. The temperature was controlled at 10-20℃, and oxygen was bubbled through. After the reaction was completed, gas chromatography analysis showed that the conversion rate of the 3-oxetane was 99.5%. The reaction solution was filtered, and the catalyst was washed with dichloromethane. The catalyst washing solution was combined with the reaction solution, and most of the solvent dichloromethane was removed by atmospheric distillation. Then, 3-oxetane was obtained by vacuum distillation with a yield of 85.8% and a purity of 99.7%.

[0045] The recovered catalyst obtained in Example 1 was washed with methanol and then air-dried. The catalyst reuse experiment was repeated under the conditions of Example 1, and the results are as follows:

[0046]

Claims

1. The application of a catalyst in the oxidation of 3-oxetane to 3-oxetane, characterized in that, The catalyst is CuO-Fe2O3-MnO2 / Al2O3, wherein the support is Al2O3, and the active component CuO has a mass content of 1%–10%; Fe2O3 has a mass content of 0.5%–2%; and MnO2 has a mass content of 0.5%–2%. Based on the total mass of the catalyst, the catalyst is added to a mixture of 3-oxetanebutanol and an organic solvent, and an oxidant is introduced or added dropwise at a certain temperature to carry out an oxidation reaction. After the reaction is completed, solid-liquid separation is performed, and the liquid portion is purified to obtain 3-oxetanebutanone. The reaction conditions are as follows: (1) The amount of catalyst used is 1 to 10 wt% of 3-oxetanebutanol; (2) The molar ratio of the oxidant to 3-oxetanebutanol is 1 to 1.5:1; (3) The oxidation reaction temperature is 0 to 100℃.

2. The application of the catalyst according to claim 1 in the oxidation of 3-oxetane to 3-oxetane, characterized in that, The Al2O3 mentioned is of the α, β, or γ type.

3. The application of the catalyst according to claim 1 or 2 in the oxidation of 3-oxetane to 3-oxetane, characterized in that, The Al2O3 is preferably of the γ type.

4. The application of the catalyst according to claim 1 in the oxidation of 3-oxetane to 3-oxetane, characterized in that, The catalyst preparation method includes the following steps: (1) Weigh a certain amount of Cu(NO3)2·3H2O, Fe(NO3)3·9H2O, and Mn(NO3)2 50% aqueous solution and dissolve them in deionized water to prepare solution A, in which the total concentration of metal ions is 0.1~1mol / L; (2) Weigh a certain amount of carbonate and dissolve it in deionized water to prepare precipitant solution B, with a carbonate concentration of 0.1-0.5 mol / L; (3) Weigh a certain amount of Al2O3 and polyethylene glycol (PEG), disperse them in deionized water to prepare solution C, wherein the concentration of Al2O3 is 100 g / L and the concentration of polyethylene glycol is 0.01 mol / L; (4) Stir and heat solution C to 70°C. Add solution A and solution B dropwise to solution C simultaneously and in parallel, controlling the endpoint pH = 7-8. After the addition is complete, keep warm and age for 2 hours. Then cool down and filter, wash with deionized water, dry the filter cake at 100°C for 2 hours, and then calcine at 300-500°C for 2 hours to obtain the catalyst.

5. The application of the catalyst according to claim 4 in the oxidation of 3-oxetane to 3-oxetane, characterized in that, In step (2), the carbonate is one of Na2CO3, K2CO3, and (NH4)2CO3.

6. The application of the catalyst according to claim 4 in the oxidation of 3-oxetane to 3-oxetane, characterized in that, In step (3), the polyethylene glycol is either PEG2000 or PEG4000.

7. The application of the catalyst according to claim 1 in the oxidation of 3-oxetane to 3-oxetane, characterized in that, The oxidant is one of air, oxygen, or hydrogen peroxide.

8. The application of the catalyst according to claim 1 in the oxidation of 3-oxetane to 3-oxetane, characterized in that, The organic solvent is one or more selected from acetone, dichloromethane, trichloromethane, dichloroethane, tetrachloroethane, tetrahydrofuran, ethyl acetate, n-hexane, and cyclohexane.

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