CN119930545A

CN119930545A - A method for preparing cyclohexene oxide

Info

Publication number: CN119930545A
Application number: CN202311452022.7A
Authority: CN
Inventors: 王洋; 贾立明; 白红鑫; 杨帆
Original assignee: Sinopec Dalian Petrochemical Research Institute Co ltd; China Petroleum and Chemical Corp
Current assignee: Sinopec Dalian Petrochemical Research Institute Co ltd; China Petroleum and Chemical Corp
Priority date: 2023-11-03
Filing date: 2023-11-03
Publication date: 2025-05-06

Abstract

The invention discloses a method for preparing cyclohexene oxide, which comprises the following steps of taking a titanium silicon molecular sieve Ti-MWW of which the surface is loaded with a covalent organic framework material LZU-1 as a catalyst and catalyzing cyclohexene epoxidation reaction to generate the cyclohexene oxide in the presence of a solvent and an oxidant. The covalent organic framework material is modified outside the inorganic material titanium-silicon molecular sieve, so that the obtained composite molecular sieve catalyst has good catalyst activity in the reaction of preparing the cyclohexene oxide by epoxidation of cyclohexene, and the reaction conversion rate is greatly improved.

Description

Method for preparing epoxycyclohexane

Technical Field

The invention belongs to the field of fine chemical industry, and particularly relates to a method for preparing cyclohexene oxide by catalyzing the reaction of cyclohexene and hydrogen peroxide by using a composite molecular sieve as a catalyst.

Background

Epoxides are an important class of intermediates in the fields of petrochemical, fine chemical, pharmaceutical synthesis, and the like. The epoxy cyclohexane is an important epoxy compound, the epoxy group of the epoxy cyclohexane is quite active, and the epoxy cyclohexane can be converted into a series of other compounds with wide application range through a selective ring opening mode, and the epoxy cyclohexane is applied to the production of pesticides and plasticizers, the synthesis of degradable material monomers and the like, and has good market prospect. The traditional process uses a light oil waste liquid recovery method to obtain the cyclohexene oxide, but the yield is limited by the yields of the main products of cyclohexanone and cyclohexanol, and the purity of the product is low, so that the development of the cyclohexene oxide is severely restricted. Therefore, the method for producing the epoxycyclohexane by the organic synthesis method is a main source of the epoxycyclohexane at present at home and abroad.

With the maturation of the technology for preparing cyclohexene by unsaturated hydrogenation of benzene, the technology for preparing cyclohexene oxide by using cyclohexene as a raw material through epoxidation reaction is widely paid attention to by researchers. According to different oxidants, the method for synthesizing the epoxy cyclohexane at home and abroad mainly comprises the following preparation routes, namely an organic peroxyacid method, a peroxyformic acid or acetic acid and the like which are commonly used as oxidants, wherein the peroxyformic acid is unstable and is easy to decompose, a hypochlorous acid oxidation method, a method for adding cyclohexene and HOCl and condensing the same into a ring is firstly reported by Japanese patent, a large amount of waste water is generated by using the method, and the method needs to be treated by strong alkali, so that the environmental pollution is large, an aldehyde is needed to be used as a co-oxidant in the molecular oxygen oxidation method, the route is cleaner and environment-friendly, the yield is low, the separation is complex, the hydrogen peroxide oxidation method is low in price and environment-friendly, an oxidation product is nontoxic, harmless and pollution-free water, and accords with the development trend of the current green chemistry, and the hydrogen peroxide is generally needed to be added with a high-efficiency catalyst in the reaction process to improve the activity.

The hydrogen peroxide oxidation method accords with the current development trend of green chemistry, and has good application prospect if a high-efficiency catalyst can be developed. In the current report, the novel catalytic oxidation system composed of the titanium silicon molecular sieve and hydrogen peroxide overcomes the problems of harsh conditions and environmental pollution in the traditional process, and has better catalytic activity in the synthesis of propylene oxide. However, when the catalyst is applied to a cyclohexene epoxidation system, the catalyst has the defects of low cyclohexene conversion rate, low target product yield and the like.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a method for preparing cyclohexene oxide. The covalent organic framework material is modified outside the inorganic material titanium-silicon molecular sieve, so that the obtained composite molecular sieve catalyst has good catalyst activity in the reaction of preparing the cyclohexene oxide by epoxidation of cyclohexene, and the reaction conversion rate is greatly improved.

The method for preparing the cyclohexene oxide comprises the following steps of taking a titanium silicon molecular sieve Ti-MWW of which the surface is loaded with a covalent organic framework material LZU-1 as a catalyst and marking the catalyst as LZU-1@Ti-MWW, and catalyzing cyclohexene epoxidation reaction to generate the cyclohexene oxide in the presence of a solvent and an oxidant.

In the method, the weight of the catalyst is 0.8% -9.0% of LZU-1, and the weight of the catalyst is 91.0% -99.2% of Ti-MWW. The preparation method of the catalyst LZU-1@Ti-MWW comprises the following steps of uniformly mixing titanium-silicon molecular sieve Ti-MWW, trimellitic aldehyde, p-phenylenediamine and ethanol, adding an aqueous solution of acetic acid, carrying out hydrothermal crystallization, washing and drying to obtain the catalyst.

Wherein the mass ratio of the Ti-MWW, the trimellitic aldehyde, the p-phenylenediamine and the ethanol is 1:0.05-0.3:0.05-0.3:5-15.

The concentration of the acetic acid aqueous solution is 1 mol/L-6 mol/L, and the addition amount is 0.1-0.5 mL.

The hydrothermal crystallization treatment is generally carried out in a high-pressure reaction kettle, the hydrothermal crystallization condition is 100-150 ℃, and the reaction is carried out for 2-5 days.

The washing process is a conventional suction filtration washing process in the field of molecular sieves, for example, absolute ethyl alcohol can be adopted for washing for 2-5 times, and the filtrate is colorless.

The drying condition is that the drying temperature is 60-100 ℃ and the drying time is 4-6 hours.

In the method, the oxidant is one or more of hydrogen peroxide solution and tert-butyl hydrogen peroxide solution, the mass concentration of the oxidant is 30% -70%, the dosage is 0.2-2.0 g H ₂O₂/g cyclohexene, and preferably 1.0-1.5 g H ₂O₂/g cyclohexene.

In the method of the invention, the solvent is one or more of methanol, acetonitrile, dimethyl sulfoxide and N, N-dimethylformamide, preferably acetonitrile.

In the method, the cyclohexene epoxidation reaction condition is that the reaction temperature is 50-90 ℃ and the reaction time is 2-6 hours.

In the method, the dosage of LZU-1@Ti-MWW is 0.05-0.75 g/g cyclohexene, and the dosage of the catalyst is preferably 0.1-0.3 g/g cyclohexene.

Compared with the prior art, the preparation method has the advantages that the novel organic-inorganic composite catalytic material LZU-1@Ti-MWW is prepared by adopting the method of depositing covalent organic framework materials on the surface of the titanium-silicon molecular sieve, the polarity of the surface of the titanium-silicon molecular sieve can be regulated and controlled by controlling the addition of organic monomers, the preparation method is simple and easy to operate, and the composite catalyst is used in the reaction process of preparing the cyclohexene oxide, has mild conditions, improves the catalytic activity compared with the titanium-silicon molecular sieve which is not deposited on the surface, and obtains higher raw material conversion rate at lower reaction temperature.

Drawings

FIG. 1 is a scanning electron microscope photograph of a titanium silicalite molecular sieve Ti-MWW.

FIG. 2 is a scanning electron micrograph of the catalyst LZU-1@Ti-MWW of example 1.

Detailed Description

The invention will be further illustrated with reference to the following specific examples, which are not intended to limit the same.

Example 1

16Mg of trimellitic aldehyde, 16mg of p-phenylenediamine, 0.2g of Ti-MWW and 2mL of ethanol are placed in a 10mL pressure-resistant tube, after full shaking and ultrasonic treatment, 0.2mL of 3mol/L acetic acid aqueous solution is added, the upper air of the solution is replaced by nitrogen, and then the solution is placed in an oven at 120 ℃ for 3 days of reaction. The obtained solid powder was filtered, washed three times with absolute ethanol, dried at 100℃for 6 hours and calcined at 200℃for 4 hours to give LZU-1@Ti-MWW-1 catalyst.

Example 2

32Mg of trimellitic aldehyde, 32mg of p-phenylenediamine, 0.2g of Ti-MWW and 2mL of ethanol are placed in a 10mL pressure-resistant tube, after full shaking and ultrasonic treatment, 0.2mL of 3mol/L acetic acid aqueous solution is added, the upper air of the solution is replaced by nitrogen, and then the solution is placed in an oven at 120 ℃ for 3 days of reaction. The obtained solid powder was filtered, washed three times with absolute ethanol, dried at 100℃for 6 hours and calcined at 200℃for 4 hours to give the LZU-1@Ti-MWW-2 catalyst.

Example 3

48Mg of trimellitic aldehyde, 48mg of p-phenylenediamine, 0.2g of Ti-MWW and 2mL of ethanol are placed in a 10mL pressure-resistant tube, after full shaking and ultrasonic treatment, 0.2mL of 3mol/L acetic acid aqueous solution is added, the upper air of the solution is replaced by nitrogen, and then the solution is placed in an oven at 120 ℃ for 3 days of reaction. The obtained solid powder was filtered, washed three times with absolute ethanol, dried at 100℃for 6 hours and calcined at 200℃for 4 hours to give the LZU-1@Ti-MWW-3 catalyst.

Example 1-3A COF deposition layer catalyst material with different deposition amounts on the surface was synthesized, wherein the deposition amount of the LZU-1@Ti-MWW-1 catalyst COF was 1.5wt%, the deposition amount of the LZU-1@Ti-MWW-3 catalyst COF was 4.3wt%, and the deposition amount of the LZU-1@Ti-MWW-2COF was 2.9wt%.

Example 4 catalytic epoxidation performance was evaluated by adding 10mL of acetonitrile solvent, 3.2g of cyclohexene as the reactant, 4.5g of a 30.0% by mass hydrogen peroxide solution, and finally adding 0.6g of a complex catalyst in a flask having a volume of 50mL, setting the reaction temperature to 65 ℃ and the reaction time to 5 hours under stirring. After the reaction is completed, the conversion, selectivity and yield are analyzed by gas chromatography.

The results of the catalytic performance are summarized in Table 1, from which it is clear that the catalyst LZU-1@Ti-MWW-1 has higher catalytic activity and epoxide yield.

Table 1 example 4 results of catalyst performance test

Catalyst	Cyclohexene conversion/%	Cyclohexane oxide selectivity/%
			LZU-1@Ti-MWW-1	96.1	94.3
LZU-1@Ti-MWW-2	92.1	85.2
			LZU-1@Ti-MWW-3	65.7	79.1

Example 5

In a flask with a volume of 50mL, 10mL of acetonitrile solvent, 3.2g of cyclohexene reactant and 3.6g of hydrogen peroxide solution with a mass concentration of 30.0% are sequentially added, and finally 0.6g of LZU-1@Ti-MWW-1 composite catalyst is added, wherein the reaction temperature is set to be 50 ℃ under the stirring state, and the reaction time is set to be 5h. After the reaction was completed, cyclohexene conversion was 53.5% and the selectivity was 68.0% by gas chromatography.

Example 6

In a flask with a volume of 50mL, 10mL of methanol solvent, 3.2g of cyclohexene as a reactant and 1.6g of a tert-butyl hydroperoxide solution with a mass concentration of 70.0% were sequentially added, and finally 0.6g of LZU-1@Ti-MWW-1 composite catalyst was added, and the reaction temperature was set to 80 ℃ and the reaction time was set to 5h under stirring. After the reaction was completed, cyclohexene conversion was 85.1% by gas chromatography with a selectivity of 82.3%.

Example 7

In a flask with a volume of 50mL, 10mL of acetonitrile solvent, 3.2g of cyclohexene reactant and 4.5g of hydrogen peroxide solution with a mass concentration of 50.0% are sequentially added, and finally 1.2g of LZU-1@Ti-MWW-1 composite catalyst is added, wherein the reaction temperature is set to be 90 ℃ under the stirring state, and the reaction time is set to be 2 hours. After the reaction is completed, the cyclohexene conversion rate is 98.3% and the selectivity is 92.1% by gas chromatography.

Comparative example 1

In a flask with a volume of 50mL, 10mL of acetonitrile solvent, 3.2g of cyclohexene reactant and 4.5g of hydrogen peroxide solution with a mass concentration of 30.0% are sequentially added, and finally 0.6g of Ti-MWW catalyst is added, wherein the reaction temperature is set to be 80 ℃ and the reaction time is set to be 5h under a stirring state. After the reaction was completed, the cyclohexene conversion was 64.0% and the cyclohexene oxide selectivity was 71.5% by gas chromatography.

Comparative example 2

In a flask with a volume of 50mL, 10mL of acetonitrile solvent, 3.2g of cyclohexene reactant and 3.6g of hydrogen peroxide solution with a mass concentration of 30.0% are sequentially added, and finally 0.6g of Ti-MWW catalyst is added, wherein the reaction temperature is set to be 50 ℃ and the reaction time is set to be 5h under a stirring state. After the reaction was completed, the cyclohexene conversion was 27.6% and the cyclohexene oxide selectivity was 63.1% by gas chromatography.

By comparing LZU-1@Ti-MWW with Ti-MWW, the composite catalyst disclosed by the invention has higher catalytic activity, and can be used for improving the raw material conversion rate and the target product selectivity in the process of producing the cyclohexene oxide by cyclohexene oxidation.

Claims

1. A method for preparing cyclohexene oxide, characterized in that it includes the following contents: using a titanium silicon molecular sieve Ti-MWW with a surface-loaded covalent organic framework material LZU-1 as a catalyst, denoted as LZU-1@Ti-MWW, to catalyze the epoxidation reaction of cyclohexene to produce cyclohexene oxide in the presence of a solvent and an oxidant.

2. The method according to claim 1, characterized in that: the catalyst is based on weight, LZU-1 is 0.8%~9.0%, and Ti-MWW is 91.0%~99.2%.

3. The method according to claim 1 is characterized in that: the preparation method of the catalyst LZU-1@Ti-MWW comprises the following contents: after uniformly mixing titanium silicon molecular sieve Ti-MWW, isophthalic acid, p-phenylenediamine and ethanol, adding acetic acid aqueous solution, hydrothermally crystallizing, and then washing and drying to obtain the catalyst.

4. The method according to claim 3, characterized in that the mass ratio of the titanium silicon molecular sieve Ti-MWW, mesitylene tribenzaldehyde, p-phenylenediamine and ethanol is: 1:0.05~0.3:0.05~0.3:5~15.

5. The method according to claim 3, characterized in that the concentration of the acetic acid aqueous solution is 1 mol/L~6 mol/L, and the amount added is 0.1~0.5 mL.

6. The method according to claim 3, characterized in that: the hydrothermal crystallization treatment is generally carried out in a high-pressure reactor, the hydrothermal crystallization conditions are 100-150°C, and the reaction time is 2-5 days.

7. The method according to claim 3, characterized in that: the drying conditions are: drying temperature is 60-100°C, and drying time is 4-6 hours.

8. The method according to claim 1, characterized in that: the oxidant is one or more of hydrogen peroxide solution and tert-butyl hydroperoxide solution, the mass concentration of the oxidant is 30% to 70%, and the amount used is 0.2 to _2.0 g _H2O2 /g cyclohexene, preferably 1.0 to 1.5 g _H2O2 /g _cyclohexene .

9. The method according to claim 1, characterized in that the solvent is one or more of methanol, acetonitrile, dimethyl sulfoxide, N,N-dimethylformamide, preferably acetonitrile.

10. The method according to claim 1, characterized in that the cyclohexene epoxidation reaction conditions are: reaction temperature 50-90°C, reaction time 2-6h.

11. The method according to claim 1, characterized in that the amount of LZU-1@Ti-MWW is 0.05-0.75 g/g cyclohexene, and preferably the amount of the catalyst is 0.1-0.3 g/g cyclohexene.