Method for synthesizing cyclohexanone compound through selective semi-hydrogenation of benzenediol compound

Abstract

The invention discloses a method for synthesizing cyclohexanone compounds through selective semi-hydrogenation of benzenediol compounds, which comprises the following steps: adding a supported palladium catalyst, biomass derived benzenediol compounds and a solvent into a high-pressure reaction kettle, introducing reaction gas to pressurize, and carrying out selective hydrogenation reaction at 50-200 DEG C and 0.5-5 MPa for 2-20 hours to obtain the cyclohexanone compounds, according to the present invention, the loading capacity of palladium in the supported palladium catalyst is 0.05-5%, the carrier is one of TiO2-Rutile, TiO2-Anatase, CeO2, HAP, Al2O3, MgO, Fe2O3, ZnO, WO3, CuO, Co3O4 and SiO2, the preparation method is simple, the metal loading capacity is low, the minimum particle size is 1.36 nm, the dispersity is high, the catalyst is used for the catalytic hydrogenation reaction of benzenediol, and the benzenediol can be subjected to high-selectivity hydrogenation to synthesize the ketone compound.

Description

Technical field:

[0001] The invention relates to the technical field of selective catalytic hydrogenation, and in particular to a method for synthesizing cyclohexanone compounds by selective semi-hydrogenation of diphenol compounds. Background technology:

[0002] Cyclohexanone compounds have important practical value in the chemical industry. For example, cyclohexanone, as an important chemical raw material, is mainly used to produce chemical intermediates such as caprolactam and adipic acid, while caprolactam and adipic acid are important monomers for producing nylon 6 and nylon 66. Cyclohexanedione is mainly used in the fields of medicine, organic synthesis, pesticides and semiconductor materials. Among hydroxycyclohexanone compounds, 2-hydroxycyclohexanone is used in downstream products including adipaldehyde, adipic acid semialdehyde, methyl ester, etc., which are further used in industries such as plastics, rubber, and coatings; 3-hydroxycyclohexanone is mainly used in pharmaceutical intermediates, polymer materials, coatings and adhesives, etc.; 4-hydroxycyclohexanone is mainly used in the synthesis of medicines, liquid crystal materials, and pesticides and insecticides. In the prior art, the reaction of thermal catalysis to prepare cyclohexanone compounds will generate some by-products such as methanol, cyclohexanol, and cyclohexane, and faces the problem of separation and utilization of by-products. It is crucial to develop a green and efficient technical route for the synthesis of cyclohexanone compounds to simplify the production process, improve production efficiency, and reduce energy consumption.

[0003] CN 104672069 B discloses a method for preparing cyclohexanone or substituted cyclohexanone, which is characterized in that the method uses phenol, o-methylphenol, p-methylphenol, m-methylphenol, p-tert-butylphenol or o-methoxyphenol as a raw material, uses Pd-TiN as a catalyst, reacts at 30-100° C. and 0.1-1 MPa hydrogen pressure, and stirs for 1-12 hours, and then obtains cyclohexanone or substituted cyclohexanone through extraction, concentration and drying steps.

[0004] Compared with phenol and other monophenols, diphenol carries two hydroxyl groups, which will produce a variety of hydrogenation products during the hydrogenation process. Therefore, hydroxycyclohexanone compounds are currently mainly obtained by oxidation of alcohol compounds, which has high raw material costs, complex reactions, and many by-products. Since diphenols are more difficult to control to generate semi-hydrogenated ketone compounds than monophenols, there is currently almost no research showing that there is a catalyst that can simultaneously achieve green environmental protection and high activity and selectivity to convert the above biomass-derived phenolic compounds into cyclohexanone compounds. Summary of the invention:

[0005] The purpose of the present invention is to provide a method for synthesizing cyclohexanone compounds by selective semi-hydrogenation of diphenol compounds.

[0006] The present invention is achieved through the following technical solutions:

[0007] A method for synthesizing cyclohexanone compounds by selective semi-hydrogenation of diphenol compounds, the method comprising the following steps:

[0008] A supported palladium catalyst, a biomass-derived hydroquinone compound, and a solvent are added to a high-pressure reactor, and a reaction gas is introduced to increase the pressure. A selective hydrogenation reaction is carried out at 50-200° C., preferably 120-150° C., most preferably 150° C., and 0.5-5 MPa, preferably 0.5-1 MPa, and most preferably 1 MPa for 2-20 hours, most preferably 4 hours, to obtain cyclohexanone compounds; the loading amount of palladium in the supported palladium catalyst is 0.05%-5%, preferably 0.1%-3%; most preferably 0.1%, and the carrier is one of TiO2-Rutile, TiO2-Anatase, CeO2, HAP, Al2O3, MgO, Fe2O3, ZnO, WO3, CuO, Co3O4 and SiO2, preferably TiO2-Rutile, TiO2-Anatase, CeO2, HAP, and most preferably TiO2-Rutile.

[0009] The biomass-derived catechol compound is one of hydroquinone, catechol or resorcinol.

[0010] The solvent is one or more of pure water, methanol, ethanol, isopropanol, acetonitrile, ether, toluene and ethyl acetate, preferably one or more of pure water and ethanol, and most preferably pure water.

[0011] The mass ratio of the supported palladium catalyst to the biomass-derived diphenol compound is 1:(0.05-50), preferably 1:(0.05-20), and most preferably 1:2.

[0012] The preparation method of the supported palladium catalyst is as follows: dissolving a palladium precursor in water to prepare a palladium-containing solution with a palladium concentration of 0.001 to 0.1 g / mL, preferably 0.002 to 0.06 g / mL, and most preferably 0.002 g / mL, and then dispersing a carrier into the palladium-containing solution, wherein the mass ratio of the carrier to the solution is 1:20 to 100, more preferably 1:(40 to 60), and most preferably 1:50. After ultrasonic-assisted dispersion, a precipitant sodium hydroxide is added dropwise under continuous stirring, wherein the concentration is 0.01 to 1 M, and most preferably 0.1 M. The pH value is adjusted to 8 to 14, and most preferably 12, 20 to 80° C., and most preferably room temperature 27° C., and the precipitation reaction is continuously stirred. The catalyst is washed with water and filtered to remove excess water, dried overnight and ground into powder, and then calcined and reduced to obtain a highly dispersed supported palladium catalyst; the calcination atmosphere is one or more of air, nitrogen, and argon, preferably air, the calcination temperature is 200-600°C, more preferably 350-550°C; most preferably 350°C, the calcination time is 2-6 hours, more preferably 4-6 hours, and most preferably 4 hours; the reducing atmosphere is composed of hydrogen and nitrogen, the hydrogen-nitrogen ratio is 1:(1-10), most preferably 1:9, the reduction temperature is 200-600°C, preferably 200-400°C, most preferably 200°C, the reduction time is 0.5-1h, and most preferably 1h.

[0013] The beneficial effects of the present invention are as follows:

[0014] 1. The catalyst preparation method is simple, the metal loading is low, the minimum particle size is 1.36nm, and the dispersion is high. It is used for the catalytic hydrogenation reaction of diphenol, and can highly selectively hydrogenate diphenol to synthesize ketone compounds.

[0015] 2. The synthesis method provided by the present invention uses cheap and readily available biomass-derived hydroquinone compounds as substrates, and efficiently converts them into cyclohexanone compounds in one step. The conditions are mild, the synthesis process is simple, green and environmentally friendly, and there is no environmental pollution. It can effectively alleviate environmental pollution and energy crisis problems. Description of the drawings:

[0016] Figure 1 is a TEM image of the Pd / TiO2-Rutile catalyst described in Example 1;

[0017] Figure 2 is a TEM image of the Pd / TiO2-Rutile catalyst described in Comparative Example 1;

[0018] Figure 3 This is the gas phase high-resolution mass spectrum with hydroquinone as the substrate as described in Example 1;

[0019] Figure 4 is a gas phase high-resolution mass spectrum with resorcinol as a substrate as described in Example 12;

[0020] Figure 5 This is the gas phase high-resolution mass spectrum of Example 13 using catechol as the substrate. Specific implementation method:

[0021] The following is a further description of the present invention, rather than a limitation of the present invention.

[0022] Embodiment 1:

[0023] (1) A palladium nitrate precursor was added to a beaker containing 50 mL of water to prepare a palladium solution with a Pd content of 0.002 g / mL. After sufficient stirring, 1.0 g of TiO2-Rutile (Rutile type in TiO2) carrier was dispersed in the water. After ultrasonication for 10 min, a 0.1 M NaOH solution was added dropwise under continuous stirring. After adjusting the pH to 12 h, the mixture was stirred continuously at room temperature for 6 h. The mixture was washed with water and filtered to remove excess water, and dried at 60° C. overnight. The dried product was ground into powder in a mortar, calcined at 350° C. for 4 h, and reduced at 200° C. for 1 h in a hydrogen atmosphere to obtain a TiO2-Rutile catalyst with a palladium loading of 0.1% (hereinafter referred to as a Pd-Rutile catalyst with a loading of 0.1%). The TEM image thereof is shown in FIG. Figure 1 , particle size is 1.36nm, and the dispersion is high.

[0024] (2) Add the palladium-loaded TiO2-Rutile catalyst prepared in step (1) with a palladium loading of 0.1%, 0.1M hydroquinone and water into a reactor, replace the air in the reactor 5 to 7 times, add the reaction gas hydrogen to 1MPa, and then carry out a selective hydrogenation reaction at 150°C. After the reaction is completed, cool to room temperature, take out the reaction solution, filter out the catalyst, analyze the filtrate by gas chromatography, and calculate the conversion rate, selectivity and yield. The conversion rate is 100%, and the selectivity of cyclohexanone compounds in the product is 99%.

[0025] Comparative Example 1

[0026] Refer to Example 1, except that: ultrasonic assisted dispersion is not used in step (1), and the remaining steps are the same. The Pd-Rutile catalyst with a loading of 0.1% was used to catalyze the selective hydrogenation of hydroquinone, with a conversion rate of 76% and a selectivity of cyclohexanone compounds in the product of 99%; its TEM image is shown in Figure 2 , particle size is 2.64nm.

[0027] Example 2

[0028] Referring to Example 1, the difference is that in step (1), the oxide carrier is anatase type in TiO2, and the other steps are the same. The Pd-Anatase catalyst with a loading of 0.1% is used to catalyze the selective hydrogenation of hydroquinone, with a conversion rate of 16% and a selectivity of cyclohexanone compounds in the product of 99%.

[0029] Example 3

[0030] Refer to Example 1, except that: in step (1), the oxide carrier is commercial CeO2 that has been calcined at 350°C for 4 hours, and the resulting Pd-CeO2 catalyst with a loading of 0.1% catalyzes the selective hydrogenation of hydroquinone with a conversion rate of 31% and a selectivity of cyclohexanone compounds in the product of 35%.

[0031] Example 4

[0032] Referring to Example 1, the difference is that in step (1), the oxide carrier is commercial HAP that has been calcined at 350° C. for 4 hours. The resulting Pd-HAP catalyst with a loading of 0.1% catalyzes the selective hydrogenation of hydroquinone with a conversion rate of 15% and a selectivity of cyclohexanone compounds in the product of 99%.

[0033] Example 5

[0034] Refer to Example 1, except that: in step (1), commercial Al2O3 is used as the oxide carrier, and the Pd-Al2O3 catalyst with a loading of 0.1% is used to catalyze the selective hydrogenation of hydroquinone, with a conversion rate of 33% and a selectivity of cyclohexanone compounds in the product of 64%.

[0035] Example 6

[0036] Referring to Example 1, the difference is that in step (1), SiO2 is used as the oxide carrier, and in step (2), the hydrogenation reaction substrate is 0.1M hydroquinone, and the remaining steps are the same. The Pd-SiO2 catalyst with a loading of 0.1% is used to catalyze the selective hydrogenation of hydroquinone, with a conversion rate of 5% and a selectivity of cyclohexanone compounds in the product of 100%.

[0037] Example 7

[0038] Referring to Example 1, the difference is that the Pd content in step (1) is 0.001 g / mL, and the other steps are the same. The Pd-TiO2 catalyst with a loading of 0.05% is used to catalyze the selective hydrogenation of hydroquinone, with a conversion rate of 39% and a selectivity of cyclohexanone compounds in the product of 91%.

[0039] Example 8

[0040] Referring to Example 1, the difference is that the Pd content in step (1) is 0.01 g / mL, and the other steps are the same. The Pd-TiO2 catalyst with a loading of 0.5% is used to catalyze the selective hydrogenation of hydroquinone, with a conversion rate of 100% and a selectivity of cyclohexanone compounds in the product of 81%.

[0041] Example 9

[0042] Referring to Example 1, except that the Pd content in step (1) is 0.02 g / mL, and the remaining steps are the same, the Pd-TiO2 catalyst with a loading of 1% is used to catalyze the selective hydrogenation of hydroquinone, with a conversion rate of 100% and a selectivity of cyclohexanone compounds in the product of 76%.

[0043] Example 10

[0044] Referring to Example 1, the difference is that the Pd content in step (1) is 0.06 g / mL, and the other steps are the same. The Pd-TiO2 catalyst with a loading of 3% is used to catalyze the selective hydrogenation of hydroquinone, with a conversion rate of 100% and a selectivity of cyclohexanone compounds in the product of 86%.

[0045] Embodiment 11

[0046] Referring to Example 1, the difference is that the Pd content in step (1) is 0.1 g / mL, and the other steps are the same. The Pd-TiO2 catalyst with a loading of 5% is used to catalyze the selective hydrogenation of hydroquinone, with a conversion rate of 100% and a selectivity of cyclohexanone compounds in the product of 63%.

[0047] Example 12

[0048] Referring to Example 1, the difference is that the hydrogenation reaction substrate in step (2) is 0.1M resorcinol, and the other operation steps are the same. The Pd-TiO2 catalyst with a loading of 0.1% is used to catalyze the selective hydrogenation of resorcinol, with a conversion rate of 100% and a selectivity of cyclohexanone compounds in the product of 99%.

[0049] Embodiment 13

[0050] Referring to Example 1, the difference is that the hydrogenation reaction substrate in step (2) is 0.1M catechol, and the other operation steps are the same. The Pd-TiO2 catalyst with a loading of 0.1% is used to catalyze the selective hydrogenation of catechol, and the conversion rate is 51%, and the selectivity of cyclohexanone compounds in the product is 76% and the selectivity of cyclohexanol is 23%.

[0051] It can be seen from the above examples that the palladium-based catalyst prepared by the present invention can efficiently and selectively hydrogenate unsaturated diphenol compounds into cyclohexanone compounds, and the product types are relatively single, with almost no saturated products.

[0052] The description of the above embodiments is only used to help understand the technical solution and core ideas of the present invention. It should be pointed out that for technicians in this technical field, several improvements and modifications can be made to the present invention without departing from the principles of the present invention. These improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for synthesizing cyclohexanone compounds by selective semi-hydrogenation of diphenol compounds, characterized in that: The method comprises the following steps: adding a supported palladium catalyst, a biomass-derived hydroquinone compound and a solvent into a high-pressure reactor, introducing a reaction gas for pressurization, and performing a selective hydrogenation reaction at 50-200° C. and 0.5-5 MPa for 2-20 hours to obtain a cyclohexanone compound; the supported palladium catalyst has a supported amount of 0.05%-5%, and the carrier is one of TiO2-Rutile, TiO2-Anatase, CeO2, HAP, Al2O3, MgO, Fe2O3, ZnO, WO3, CuO, Co3O4 and SiO2.

2. The method according to claim 1, characterized in that The reaction temperature is 120-150°C, the pressure is 0.5-1MPa, and the reaction time is 4h.

3. The method according to claim 1, characterized in that The loading amount of palladium in the supported palladium catalyst is 0.1% to 3%.

4. The method according to claim 1, characterized in that: The biomass-derived catechol compound is one of hydroquinone, catechol or resorcinol.

5. The method according to claim 1, characterized in that The solvent is one or more of pure water, methanol, ethanol, isopropanol, acetonitrile, ether, toluene and ethyl acetate.

6. The method according to claim 1, characterized in that The mass ratio of the supported palladium catalyst to the biomass-derived diphenol compound is 1:(0.05-50).

7. The method according to claim 1, characterized in that The mass ratio of the supported palladium catalyst to the biomass-derived diphenol compound is 1:(0.05-20).

8. The method according to claim 1, characterized in that: The mass ratio of the supported palladium catalyst to the biomass-derived hydroquinone compound is 1:

2.

9. The method according to claim 1, characterized in that: The preparation method of the supported palladium catalyst is as follows: a palladium precursor is dissolved in water to prepare a palladium-containing solution with a palladium concentration of 0.001 to 0.1 g / mL, a carrier is dispersed in the palladium-containing solution, the mass ratio of the carrier to the solution is 1:20 to 100, after ultrasonic-assisted dispersion, a precipitant sodium hydroxide is added dropwise under continuous stirring, the concentration is 0.01 to 1 M, the pH value is adjusted to 8 to 14, a precipitation reaction is continuously stirred at 20 to 80° C., water is washed and filtered to remove excess water, the catalyst is dried overnight and ground into powder, and then calcined and reduced to obtain a highly dispersed supported palladium catalyst; the calcination atmosphere is one or more of air, nitrogen and argon, the calcination temperature is 200 to 600° C., and the calcination time is 2 to 6 hours; The reducing atmosphere is composed of hydrogen and nitrogen, the hydrogen-nitrogen ratio is 1:(1-10), the reducing temperature is 200-600°C, and the reducing time is 0.5-1h.

10. The method according to claim 1, characterized in that The preparation method of the supported palladium catalyst is as follows: a palladium precursor is dissolved in water to prepare a palladium-containing solution with a palladium concentration of 0.002-0.06 g / mL, a carrier is dispersed in the palladium-containing solution, the mass ratio of the carrier to the solution is 1:(40-60), after ultrasonic-assisted dispersion, a precipitant sodium hydroxide is added dropwise under continuous stirring, the concentration is 0.1 M, the pH value is adjusted to 12, the room temperature is 27°C and the stirring precipitation reaction is continued, the excess water is removed by water washing and suction filtration, the powder is dried overnight and ground into powder, and then calcined and reduced to obtain a highly dispersed supported palladium catalyst; the calcination atmosphere is air, the calcination temperature is 350-550°C, and the calcination time is 4-6 hours; The reducing atmosphere is composed of hydrogen and nitrogen with a hydrogen-nitrogen ratio of 1:9, the reducing temperature is 200-400°C, and the reducing time is 1h.

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