Catalyst for synthesizing cyclohexanone and derivatives thereof, preparation method of catalyst and synthesis method of cyclohexanone and derivatives thereof

Abstract

The invention belongs to the technical field of catalyst preparation and organic synthesis, and particularly relates to a catalyst for synthesizing cyclohexanone and derivatives thereof, a preparation method of the catalyst and a synthesis method of the cyclohexanone and the derivatives thereof. The catalyst for synthesizing cyclohexanone and derivatives thereof comprises a carrier (a molecular sieve or a metal oxide), and palladium and chlorine loaded on the carrier, the molecular sieve is prepared from one or more of ZSM-5, SBA-15 and SAPO-34; the metal oxide comprises zirconium oxide and / or cerium oxide; the loading capacity of palladium is 0.5-5 wt%, and the loading capacity of chlorine is 0.1-2 wt%. The catalyst provided by the invention takes the molecular sieve or the metal oxide as the carrier, can provide acidic sites and defect sites, and is beneficial to improving the catalytic activity of the catalyst. Meanwhile, the active substances are palladium and chlorine, the catalytic hydrogenation activity of the catalyst is improved through the combined action of the palladium and the chlorine, and the selectivity of the cyclohexanone and the cyclohexanone derivative which are important target products can also be improved.

Description

Technical Field

[0001] This invention relates to the fields of catalyst preparation and organic synthesis technology, and particularly to a catalyst for synthesizing cyclohexanone and its derivatives, a method for preparing the catalyst, and a method for synthesizing cyclohexanone and its derivatives. Background Technology

[0002] Lignin is an amorphous aromatic polymer with a three-dimensional structure, mainly formed by lignin monomers linked together by ether and carbon-carbon bonds. Lignin possesses unique aromatic phenolic structural units, and through efficient demethoxylation and selective hydrogenation of aromatic rings, it can be used to prepare high-value-added chemicals such as cyclohexanone or its derivatives. However, the process of preparing cyclohexanone from lignin suffers from low conversion rates and poor selectivity for the target product. Summary of the Invention

[0003] In view of this, the purpose of this invention is to provide a catalyst for the synthesis of cyclohexanone and its derivatives, a method for preparing the catalyst, and a method for synthesizing cyclohexanone and its derivatives. The catalyst provided by this invention is beneficial for improving the conversion rate of raw materials and the selectivity of target products in the preparation of cyclohexanone and its derivatives.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a catalyst for synthesizing cyclohexanone and its derivatives, comprising a support, and palladium and chlorine supported on the support; the support comprises a molecular sieve or a metal oxide; the molecular sieve comprises one or more of ZSM-5, SBA-15 and SAPO-34; the metal oxide comprises zirconium oxide and / or cerium oxide. The palladium loading is 0.5~5wt%, and the chlorine loading is 0.1~2wt%.

[0005] Preferably, the silica-to-alumina ratio of the molecular sieve is 20 to 100.

[0006] This invention also provides a method for preparing the catalyst for the synthesis of cyclohexanone and its derivatives as described in the above technical solution, comprising the following steps: The carrier is pretreated to obtain a pretreated carrier; the pretreatment is calcination. Palladium salt, aliphatic diamine, and water were mixed to obtain a palladium salt coordination system; The pretreated support and palladium salt coordination system are mixed and then subjected to aging, drying, reduction and passivation in sequence to obtain the catalyst for synthesizing cyclohexanone and its derivatives. The palladium salt is a chlorinated palladium salt.

[0007] Preferably, the calcination temperature is 500~550℃, the time is 2~24h, and the calcination atmosphere is air.

[0008] Preferably, the palladium chloride salt includes PdCl2, K2PdCl4, K2PdCl6, Pd(NH3)2Cl2, and C. 14 H 10 One or more of Cl2N2Pd; the aliphatic diamine is a water-soluble aliphatic diamine; The ratio of palladium salt to fatty diamine is 10-100 mg: 0.5-8 mL; The ratio of palladium salt to water is 10~100mg:1~10mL.

[0009] Preferably, the ratio of the pretreatment carrier to the palladium salt coordination system is 50~500mg:0.1~2mL.

[0010] Preferably, the aging time is 0.5~8h; the drying temperature is 50~120℃ and the time is 6~24h; the reduction temperature is 150~650℃ and the time is 0.5~6h, and the reduction atmosphere is a hydrogen-argon mixed atmosphere; the passivation time is 10~120min, and the passivation atmosphere is an oxygen-argon mixed system.

[0011] This invention also provides a method for synthesizing cyclohexanone and its derivatives, comprising the following steps: The catalyst, substrate, protic acid and solvent are mixed and then hydrogen gas is introduced to carry out the synthesis reaction to obtain the cyclohexanone and its derivatives. The catalyst is the catalyst for synthesizing cyclohexanone and its derivatives as described in the above technical solution or the catalyst for synthesizing cyclohexanone and its derivatives prepared by the preparation method described in the above technical solution. The substrate is a methoxylated lignin phenol monomer, which includes one or more of 2-methoxyphenol, 4-propyl-2-methoxyphenol, 4-propyl-2,6-dimethoxyphenol, 4-propenyl-2-methoxyphenol, and 4-propenyl-2,6-dimethoxyphenol.

[0012] Preferably, the protic acid is an inorganic acid, including hydrochloric acid, sulfuric acid, or phosphoric acid; the mass concentration of the hydrochloric acid is 36-38%, the mass concentration of the sulfuric acid is 96-98%, and the mass concentration of the phosphoric acid is 83-95%. The catalyst to substrate ratio is 40-60 mg: 0.5 mmol; The ratio of substrate to protic acid is 0.5 mmol: 10~100 µL.

[0013] Preferably, the pressure of the hydrogen gas is 0.1~4MPa, the temperature of the synthesis reaction is 30~250℃, and the time is 0.5~15h.

[0014] This invention provides a catalyst for the synthesis of cyclohexanone and its derivatives.

[0015] The catalyst of this invention uses molecular sieves (including one or more of ZSM-5, SBA-15, and SAPO-34) or metal oxides (including zirconium oxide and / or cerium oxide) as supports, which can provide acidic sites and defect sites, thus improving the catalytic activity of the catalyst and thereby increasing the feed conversion rate and target product selectivity in the preparation process of cyclohexanone and its derivatives. Simultaneously, palladium and chlorine are the active substances, and their combined effect also enhances the catalytic activity of the catalyst. When used in the catalytic synthesis of cyclohexanone and its derivatives from methoxylated lignin phenolic monomers, the catalyst of this invention can achieve efficient methoxy removal and selective hydrogenation of aromatic rings from lignin phenolic monomers; at the same time, it effectively avoids the excessive hydrogenation of methoxylated lignin phenolic monomers under high temperature and high pressure conditions, thus improving the selectivity of cyclohexanone and its derivatives (specifically, 2-propylcyclohexanone / 4-propylcyclohexanone). Furthermore, this invention also proposes the modification effect of chlorine on the surface of palladium particles: chlorine is a strongly electronegative atom, and after adsorbing on the palladium surface, it will reduce the electron density of palladium particles through electron-withdrawing effect and change the electronic structure of palladium surface; on the other hand, if the palladium metal particles have a small size, chlorine selectively covers more highly active sites of palladium (such as edges or corners), which can significantly inhibit the hydrogenation of C=O bonds, thereby preserving the carbonyl structure.

[0016] The present invention also provides a method for preparing the catalyst for synthesizing cyclohexanone and its derivatives as described in the above technical solution. The preparation method provided by the present invention is simple to operate.

[0017] This invention also provides a method for synthesizing cyclohexanone and its derivatives. The method uses the catalyst described in the above-mentioned technical solution as a catalyst, enabling efficient removal of methoxy groups from methoxy-containing lignin phenol monomers and selective hydrogenation of aromatic rings. Simultaneously, it effectively avoids the excessive hydrogenation of methoxy-containing lignin phenol monomers under high temperature and high pressure conditions, thus improving the selectivity of cyclohexanone and its derivatives (specifically, 2-propylcyclohexanone / 4-propylcyclohexanone). Furthermore, the addition of a protic acid further enhances the selectivity of cyclohexanone and its derivatives, preventing excessive hydrogenation to alcohols. Detailed Implementation

[0018] This invention provides a catalyst for synthesizing cyclohexanone and its derivatives, comprising a support, and palladium and chlorine supported on the support; the support comprises a molecular sieve or a metal oxide; the molecular sieve comprises one or more of ZSM-5, SBA-15 and SAPO-34; the metal oxide comprises zirconium oxide and / or cerium oxide. The palladium loading is 0.5~5wt%, and the chlorine loading is 0.1~2wt%.

[0019] The catalyst for synthesizing cyclohexanone and its derivatives provided by this invention includes a support comprising a molecular sieve or a metal oxide. In this invention, the molecular sieve comprises one or more of ZSM-5, SBA-15, and SAPO-34, more preferably ZSM-5. In this invention, the silicon-to-aluminum ratio (Si / Al) of the molecular sieve is preferably 20-100, specifically preferably 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100. In this invention, the metal oxide comprises zirconium oxide and / or cerium oxide.

[0020] The catalyst for synthesizing cyclohexanone and its derivatives provided by this invention comprises palladium and chlorine supported on the support. In this invention, the palladium loading is 0.5~5 wt%, specifically preferably 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 2.7 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, or 5 wt%; the chlorine loading is 0.1~2 wt%, specifically preferably 0.1 wt%, 0.2 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, 1.2 wt%, 1.3 wt%, 1.5 wt%, 1.8 wt%, or 2 wt%. In this invention, the palladium loading refers to the mass ratio of palladium to the mass of the support. In this invention, the palladium exists in elemental form, and the chlorine mainly serves to modify the exposed palladium surface; the palladium and chlorine interact through electrostatic forces.

[0021] This invention also provides a method for preparing the catalyst for the synthesis of cyclohexanone and its derivatives as described in the above technical solution, comprising the following steps: The carrier is pretreated to obtain a pretreated carrier; the pretreatment is calcination. Palladium salt, aliphatic diamine, and water were mixed to obtain a palladium salt coordination system; The pretreated support and palladium salt coordination system are mixed and then subjected to aging, drying, reduction and passivation in sequence to obtain the catalyst for synthesizing cyclohexanone and its derivatives. The palladium salt is a chlorinated palladium salt.

[0022] Unless otherwise specified, the raw materials used in this invention are preferably commercially available products.

[0023] The present invention pretreats the carrier to obtain a pretreated carrier; the pretreatment is calcination.

[0024] In this invention, the support comprises a molecular sieve or a metal oxide. In this invention, the molecular sieve comprises one or more of ZSM-5, SBA-15, and SAPO-34, more preferably ZSM-5. In this invention, the silicon-to-aluminum ratio (Si / Al) of the molecular sieve is preferably 20-100. In this invention, the metal oxide comprises zirconium oxide and / or cerium oxide.

[0025] In one specific embodiment of the present invention, the preferred method for preparing the ZSM-5 molecular sieve includes the following steps: mixing tetrapropylammonium hydroxide, aluminum isopropoxide, and water to obtain a mixed system; mixing the mixed system with tetraethyl orthosilicate and performing a hydrothermal reaction to obtain the ZSM-5 molecular sieve. In this invention, the water is preferably deionized water. In this invention, the preferred mass ratio of tetrapropylammonium hydroxide to water is 3.048:8.971. In this invention, the mixing of tetrapropylammonium hydroxide, aluminum isopropoxide, and water is preferably carried out under stirring (referred to as first stirring). The present invention does not specifically limit the speed and time of the first stirring, as long as the tetrapropylammonium hydroxide and aluminum isopropoxide are completely dissolved in the water. In this invention, the mixing of the mixed system and tetraethyl orthosilicate is preferably carried out under stirring (referred to as second stirring); the preferred speed of the second stirring is 1000 rpm, and the preferred time is 12 hours. In this invention, the hydrothermal reaction temperature is preferably 240°C, and the holding time is preferably 48 hours; the hydrothermal reaction is preferably a static hydrothermal reaction, and the hydrothermal reaction is preferably carried out in an oven. After the hydrothermal reaction, the invention preferably further includes: cooling the obtained material to room temperature, centrifuging it, and drying the resulting solid overnight to obtain the ZSM-5 molecular sieve; the drying temperature is preferably 80°C.

[0026] In a specific embodiment of the present invention, the method for preparing zirconium oxide preferably includes the following steps: mixing zirconium oxynitrate and water to obtain a zirconium oxynitrate solution; adding ammonia dropwise to the zirconium oxynitrate solution to carry out a reaction (denoted as the first reaction) to obtain the zirconium oxide. In the present invention, the water is preferably deionized water. In the present invention, the preferred ratio of zirconium oxynitrate to water is 3.709 g:160 mL. In the present invention, the preferred mass concentration of the ammonia is 20-30%; the preferred ratio of zirconium oxynitrate to ammonia is 3.709 g:96 mL. In the present invention, the dropwise addition is preferably done dropwise. In the present invention, the preferred temperature of the first reaction is room temperature, i.e., neither additional heating nor additional cooling is required; the preferred time is 48 h, and the time of the first reaction preferably starts from the time after the ammonia is added; the first reaction is preferably carried out under stirring conditions. After the first reaction, the present invention preferably further includes: centrifuging the obtained liquid, and sequentially drying and grinding the obtained solid overnight to obtain the zirconium oxide. In the present invention, the preferred drying temperature is 110 °C.

[0027] In a specific embodiment of the present invention, the method for preparing cerium oxide preferably includes the following steps: dissolving cerium nitrate in water to obtain a cerium nitrate solution; adding ammonia water dropwise to the cerium nitrate solution to carry out a reaction (referred to as the second reaction) to obtain the cerium oxide. In the present invention, the water is preferably deionized water. In the present invention, the preferred ratio of cerium nitrate to water is 3.474 g: 160 mL. In the present invention, the preferred mass concentration of the ammonia water is 20-30%, and the preferred ratio of cerium nitrate to ammonia water is 3.474 g: 96 mL. In the present invention, the dropwise addition is preferably done dropwise. In the present invention, the preferred temperature of the second reaction is room temperature, i.e., neither additional heating nor additional cooling is required; the preferred time is 48 h, and the timing of the second reaction preferably starts after the ammonia water is completely added; the second reaction is preferably carried out under stirring conditions. After the second reaction, the present invention preferably further includes: centrifuging the obtained liquid, and sequentially drying and grinding the obtained solid overnight to obtain the cerium oxide. In the present invention, the preferred drying temperature is 110 °C.

[0028] In this invention, when the carrier is a metal oxide, the particle size of the metal oxide is preferably 10~200nm.

[0029] In this invention, the calcination temperature is preferably 500~550℃, specifically preferably 500℃, 510℃, 520℃, 530℃, 540℃ or 550℃; the time is preferably 2~24h, specifically preferably 2h, 4h, 6h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h or 24h; the calcination atmosphere is preferably air.

[0030] In this invention, the calcination can remove template molecules, impurities, etc. from the carrier, thereby improving the purity of the carrier.

[0031] The present invention mixes palladium salt, aliphatic diamine and water to obtain a palladium salt coordination system; the palladium salt is a chlorinated palladium salt.

[0032] In this invention, the palladium chloride salt preferably includes PdCl2, K2PdCl4, K2PdCl6, Pd(NH3)2Cl2, and C. 14 H 10 One or more of Cl2N2Pd. In this invention, the chlorinated palladium salt can provide palladium and chlorine.

[0033] In this invention, the aliphatic diamine is preferably a water-soluble aliphatic diamine, and the water-soluble aliphatic diamine is preferably a low-carbon aliphatic diamine or a higher-carbon aliphatic diamine; the low-carbon aliphatic diamine preferably has 2 to 8 carbon atoms, and the low-carbon aliphatic diamine is specifically preferably ethylenediamine, propylenediamine, butanediamine, pentanediamine, hexanediamine, heptaethylenediamine, or octanediamine. In this invention, the higher-carbon aliphatic diamine preferably has 9 to 22 carbon atoms, and the higher-carbon aliphatic diamine specifically preferably includes nonanediamine, decanediamine, polyether diamine, C12-14 aliphatic diamine sulfonate, polyethylene glycol diamine, or N,N-bis(2-hydroxyethyl)-1,12-dodecanediamine.

[0034] In this invention, the preferred ratio of palladium salt to fatty diamine is 10-100 mg: 0.5-8 mL, more preferably 10-100 mg: 1 mL, and more specifically 30 mg: 1 mL or 33.5 mg: 1 mL.

[0035] In this invention, the preferred ratio of palladium salt to water is 10-100 mg: 1-10 mL, more preferably 10-100 mg: 2 mL, and more specifically 30 mg: 2 mL or 33.5 mg: 2 mL.

[0036] In this invention, the mixing of palladium salt, fatty diamine, and water preferably includes: mixing water and fatty diamine to obtain a fatty diamine solution; mixing the fatty diamine solution and palladium salt, and then sequentially performing ultrasonic dissolution and stirring. In this invention, the ultrasonic dissolution time is preferably 1-5 minutes, specifically 1 minute, 2 minutes, 3 minutes, 4 minutes, or 5 minutes. In this invention, the stirring time is preferably 1-3 hours, specifically 1 hour, 2 hours, or 3 hours.

[0037] After obtaining the pretreated support and palladium salt coordination system, the present invention mixes the pretreated support and palladium salt coordination system and sequentially performs aging, drying, reduction and passivation to obtain the catalyst for synthesizing cyclohexanone and its derivatives.

[0038] In this invention, the preferred ratio of the pretreatment carrier to the palladium salt coordination system is 50-500 mg: 0.1-2 mL, more preferably 200 mg: 0.1-2 mL, and more specifically 200 mg: 0.6 mL, 200 mg: 0.8 mL, or 200 mg: 1 mL.

[0039] In this invention, the mixing of the pretreatment carrier and the palladium salt coordination system preferably includes: adding the palladium salt coordination system dropwise to the pretreatment carrier; the dropwise addition rate is preferably 0.1~0.5 mL / min, specifically preferably 0.1 mL / min, 0.2 mL / min, 0.3 mL / min, 0.4 mL / min or 0.5 mL / min.

[0040] In this invention, the aging temperature is preferably room temperature, and the aging time is preferably 0.5~8h, more preferably 1~4h, and specifically preferably 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h, or 8h. In this invention, the aging process can improve the dispersibility of the active components.

[0041] In this invention, the drying temperature is preferably 50~120℃, more preferably 80~100℃, and specifically preferably 50℃, 60℃, 70℃, 80℃, 90℃, 100℃, 110℃, or 120℃; the drying time is preferably 6~24h, and specifically preferably 6h, 8h, 9h, 10h, 12h, 15h, 18h, 21h, or 24h. In this invention, the drying process removes water from the system.

[0042] In this invention, the reduction temperature is preferably 150~650℃, more preferably 200~500℃, and specifically preferably 150℃, 200℃, 250℃, 300℃, 350℃, 400℃, 450℃, 500℃, 550℃, 600℃, or 650℃; the heating rate to the reduction is preferably 0.5~5℃ / min, and specifically preferably 0.5℃ / min, 1℃ / min, 1.5℃ / min, 2℃ / min, 2.5℃ / min, 3℃ / min, 3.5℃ / min, 4℃ / min, 4.5℃ / min, or 5℃ / min; the time is preferably 0.5~6h, more preferably 1~4h, and specifically preferably 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, or 6h. In this invention, the reduction atmosphere is preferably a hydrogen-argon mixed atmosphere, wherein the volume ratio of hydrogen to argon in the hydrogen-argon mixed atmosphere is preferably 1:9. In this invention, the reduction can reduce palladium salt to elemental palladium.

[0043] After reduction and before passivation, the present invention preferably further includes cooling the obtained reduced material to room temperature.

[0044] In this invention, the passivation temperature is preferably room temperature, and the passivation time is preferably 10-120 min, specifically 10 min, 30 min, 60 min, 90 min, or 120 min; the passivation atmosphere is preferably an oxygen-argon mixture, and the volume ratio of oxygen to argon in the oxygen-argon mixture is preferably 0.5:99.5. In this invention, the passivation treatment can passivate the reduced material, prevent the spontaneous combustion of the palladium metal formed during reduction, and improve the stability of the catalyst.

[0045] This invention also provides a method for synthesizing cyclohexanone and its derivatives, comprising the following steps: The catalyst, substrate, protic acid and solvent are mixed and then hydrogen gas is introduced to carry out the synthesis reaction to obtain the cyclohexanone and its derivatives. The catalyst is the catalyst for synthesizing cyclohexanone and its derivatives as described in the above technical solution or the catalyst for synthesizing cyclohexanone and its derivatives prepared by the preparation method described in the above technical solution. The substrate is a methoxylated lignin phenol monomer, which includes one or more of 2-methoxyphenol, 4-propyl-2-methoxyphenol, 4-propyl-2,6-dimethoxyphenol, 4-propenyl-2-methoxyphenol, and 4-propenyl-2,6-dimethoxyphenol.

[0046] In this invention, the substrate is a methoxylated lignin phenolic monomer. In this invention, the methoxylated lignin phenolic monomer includes one or more of 2-methoxyphenol (guaiacol), 4-propyl-2-methoxyphenol (4-propylguaiacol), 4-propyl-2,6-dimethoxyphenol, 4-propenyl-2-methoxyphenol (4-propenylguaiacol), and 4-propenyl-2,6-dimethoxyphenol. In this invention, when the methoxylated lignin phenolic monomer is multiple of 2-methoxyphenol, 4-propyl-2-methoxyphenol, 4-propyl-2,6-dimethoxyphenol, 4-propenyl-2-methoxyphenol, and 4-propenyl-2,6-dimethoxyphenol, it is preferably used in the form of poplar lignin monomer oil, birch lignin monomer oil, and beech lignin monomer oil. In this invention, the poplar lignin monomer oil preferably comprises 4-propyl-2-methoxyphenol (4-propylguaiacol), 4-propyl-2,6-dimethoxyphenol, 4-propenyl-2-methoxyphenol (4-propenylguaiacol), and 4-propenyl-2,6-dimethoxyphenol. In this invention, the methoxy group (-OCH3) is a strong electron-donating group (donating electrons through both inductive and conjugation effects), significantly increasing the electron density of the benzene ring. Simultaneously, the methoxy group occupies the ortho position, hindering the contact between the catalyst active site and the benzene ring due to steric hindrance, thus reducing the reaction rate. Furthermore, if the substrate molecule contains a large alkyl chain of propyl / propenyl, even in the para position, the increased overall molecular volume can still hinder the contact between the catalyst active site and the benzene ring, reducing the diffusion and adsorption efficiency of the substrate in the solvent. In other words, methoxylated lignin phenol monomers are more difficult to catalyze than phenol; however, the catalyst provided by this invention can catalyze the synthesis reaction of methoxylated lignin phenol monomers to form cyclohexanone and its derivatives, which also shows that the catalyst provided by this invention has high catalytic activity.

[0047] In this invention, the protic acid is preferably an inorganic acid, which preferably includes hydrochloric acid, sulfuric acid, or phosphoric acid. In this invention, the mass concentration of the hydrochloric acid is preferably 36-38%. In this invention, the mass concentration of the sulfuric acid is preferably 96-98%. In this invention, the mass concentration of the phosphoric acid is preferably 83-95%. In this invention, the protic acid can further improve the selectivity of cyclohexanone and its derivatives (2-propylcyclohexanone / 4-propylcyclohexanone), avoiding excessive hydrogenation to alcohols.

[0048] In this invention, the solvent preferably comprises water and / or an organic solvent, more preferably water. In this invention, the water is preferably deionized water. In this invention, the organic solvent preferably comprises one or more of ethanol, dichloromethane, cyclohexane, or n-heptane.

[0049] In this invention, the preferred ratio of catalyst to substrate is 40-60 mg:0.5 mmol, specifically 40 mg:0.5 mmol, 50 mg:0.5 mmol or 60 mg:0.5 mmol.

[0050] In this invention, the preferred ratio of substrate to protic acid is 0.5 mmol:10~100 µL, more preferably 0.5 mmol:10~30 µL, and specifically preferably 0.5 mmol:10 µL, 0.5 mmol:20 µL, 0.5 mmol:30 µL, 0.5 mmol:40 µL, 0.5 mmol:50 µL, 0.5 mmol:60 µL, 0.5 mmol:70 µL, 0.5 mmol:80 µL, 0.5 mmol:90 µL, or 0.5 mmol:100 µL.

[0051] In this invention, the preferred ratio of substrate to solvent is 0.5 mmol: 5~10 mL, specifically 0.5 mmol: 5 mL, 0.5 mmol: 6 mL, 0.5 mmol: 7 mL, 0.5 mmol: 8 mL, 0.5 mmol: 9 mL or 0.5 mmol: 10 mL.

[0052] In this invention, the pressure of the hydrogen gas is preferably 0.1~4 MPa, specifically preferably 0.1 MPa, 0.5 MPa, 1 MPa, 1.5 MPa, 2 MPa, 2.5 MPa, 3 MPa, 3.5 MPa or 4 MPa; the temperature of the synthesis reaction is preferably 30~250℃, specifically preferably 30℃, 50℃, 100℃, 150℃, 200℃ or 250℃; the time is preferably 0.5~15h, specifically preferably 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h, 8h, 8.5h, 9h, 10h, 11h, 12h, 13h, 14h or 15h. In this invention, the synthesis reaction is preferably carried out under stirring conditions, and the stirring speed is preferably 200-800 rpm, specifically 200 rpm, 300 rpm, 400 rpm, 500 rpm, 600 rpm, 700 rpm, or 800 rpm. In this invention, the synthesis reaction is preferably carried out in a high-pressure reactor.

[0053] After the synthesis reaction is completed, the present invention preferably further includes: cooling the obtained synthesis reaction solution to room temperature, then rinsing the synthesis reaction apparatus with a solvent, extracting the collected mixture to obtain an extract phase; and concentrating the extract phase under reduced pressure to obtain the cyclohexanone and its derivatives. In the present invention, the extractant preferably includes dichloromethane or ethyl acetate.

[0054] In this invention, the cyclohexanone derivative refers to propylcyclohexanone, specifically preferably 4-propylcyclohexanone and / or 2-propylcyclohexanone.

[0055] In the synthesis of cyclohexanone and its derivatives, the catalyst of this invention enables efficient removal of methoxy groups from methoxy-containing lignin phenolic monomers and selective hydrogenation of aromatic rings; at the same time, it effectively avoids the excessive hydrogenation of methoxy-containing lignin phenolic monomers and the formation of alcohol products during high-temperature and high-pressure reactions, thereby improving the selectivity of cyclohexanone and its derivatives.

[0056] The following detailed description, in conjunction with embodiments, of the catalysts for synthesizing cyclohexanone and its derivatives provided by the present invention, their preparation methods, and the methods for synthesizing cyclohexanone and its derivatives, should not be construed as limiting the scope of protection of the present invention.

[0057] Example 1 (1) Weigh 3.048 g of tetrapropylammonium hydroxide and the corresponding stoichiometric amount of aluminum isopropoxide (Si / Al=25) and dissolve them in 8.971 g of deionized water. Stir thoroughly until completely dissolved. Add 4.167 g of tetraethyl orthosilicate to the mixture, stir at 1000 rpm for 12 h, and then transfer to a 240 °C oven for static hydrothermal reaction for 48 h. After the reaction vessel cools to room temperature, centrifuge and dry overnight at 80 °C to obtain ZSM-5 molecular sieve.

[0058] (2) ZSM-5 molecular sieve was calcined at 550℃ in air atmosphere for 12h to obtain pretreated molecular sieve.

[0059] (3) Weigh 30 mg PdCl2, add 2 mL of water and 1 mL of ethylenediamine to form an ethylenediamine solution, sonicate for 1 min until completely dissolved, and continue stirring the mixture for 2 h to obtain an ethylenediamine-coordinated palladium solution.

[0060] (4) 1 mL of the palladium solution coordinated with ethylenediamine obtained in (3) was added to 200 mg of the pretreated molecular sieve obtained in (2) at a rate of 0.2 mL / min. After aging at room temperature for 2 h, the solution was dried overnight at 80 °C. In order to reduce the metal nanoparticles, the solution was treated at 300 °C (heating rate of 2 °C / min) for 2 h in a hydrogen-argon mixed atmosphere (volume ratio of hydrogen to argon of 1:9). After cooling to room temperature, the solution was treated at oxygen-argon mixed atmosphere (volume ratio of oxygen to argon of 0.5:99.5) for 10 min to obtain the ZSM-5 molecular sieve supported palladium catalyst, wherein the loading of chlorine was 2 wt% and the loading of palladium was 3 wt%.

[0061] 50 mg of the prepared catalyst was added to a high-temperature, high-pressure reactor containing 5 mL of deionized water, 0.5 mmol of 4-propylguaiacol, and 10 µL of hydrochloric acid (36–38% by mass). Hydrogen gas at 1 MPa was simultaneously introduced, and the mixture was heated to 200 °C and reacted for 6 h. After the reaction was complete and the reactor cooled to room temperature, the inner wall of the reactor was rinsed with a large amount of deionized water, and the reaction solution was extracted multiple times with ethyl acetate. The liquid was collected, and hexadecane was added as an internal standard. Finally, qualitative and quantitative analysis of each component was performed using gas chromatography-mass spectrometry (GC-MS) and gas chromatography.

[0062] The results showed that the conversion rate of 4-propylguaiacol was 87%, and the selectivity of cyclohexanone and propylcyclohexanone was 85%.

[0063] Example 2 (1) Weigh 3.709 g of zirconium oxynitrate and add 160 mL of deionized water to dissolve it completely. Add 96 mL of ammonia water (mass concentration of 20~30%) dropwise and continue stirring at room temperature for 48 h. After centrifugation and drying at 110 °C overnight, a white blocky solid is obtained. The dried white solid is thoroughly ground to obtain zirconium oxide with a particle size of 10~30 nm.

[0064] (2) The zirconium oxide obtained in (1) was calcined at 500°C in air atmosphere for 4 hours to obtain pretreated zirconium oxide.

[0065] (3) Weigh 30 mg K2PdCl4, add 2 mL of water and 1 mL of ethylenediamine to form an ethylenediamine solution, sonicate for 1 min until completely dissolved, and continue stirring the mixture for 2 h to obtain an ethylenediamine-coordinated palladium solution.

[0066] (4) 0.6 mL of the palladium solution coordinated with ethylenediamine obtained in (3) was added to 200 mg of the pretreated zirconia obtained in step (2) at a rate of 0.2 mL / min. After aging at room temperature for 2 h, the solution was dried overnight at 80 °C. In order to reduce the metal nanoparticles, the solution was reduced at 300 °C (heating rate of 2 °C / min) for 2 h in a hydrogen-argon mixed atmosphere (volume ratio of hydrogen to argon is 1:9). After the reduction was completed, the reduced material was cooled to room temperature and then passivated at room temperature for 30 min in an oxygen-argon mixed atmosphere (volume ratio of oxygen to argon is 0.5:99.5) to obtain the zirconia-supported palladium catalyst, which is the catalyst for the synthesis of cyclohexanone and its derivatives. The loading of chlorine was 1.3 wt% and the loading of palladium was 1 wt%.

[0067] 50 mg of the prepared catalyst was added to a high-temperature, high-pressure reactor containing 5 mL of deionized water, 0.5 mmol of poplar lignin monomer oil (including 4-propylguaiacol, 4-propyl-2,6-dimethoxyphenol, 4-propenylguaiacol, and 4-propenyl-2,6-dimethoxyphenol), and 10 µL of sulfuric acid (98% concentration). Hydrogen gas at 3 MPa was simultaneously introduced, and the temperature was raised to 260 °C for 8 h. After the reaction was completed and the reactor cooled to room temperature, the inner wall of the reactor was rinsed with a large amount of deionized water, and the reaction solution was extracted multiple times with ethyl acetate. The liquid was collected, and hexadecane was added as an internal standard. Finally, qualitative and quantitative analysis of each component was performed using gas chromatography-mass spectrometry (GC-GC) and gas chromatography.

[0068] The results showed that the conversion rate of poplar lignin monomer oil was 90%, and the selectivity of cyclohexanone and propylcyclohexanone was 83%.

[0069] Example 3 (1) Weigh 3.474 g of cerium nitrate and add 160 mL of deionized water to dissolve it completely. Add 96 mL of ammonia water (mass concentration of 20-30%) dropwise and continue stirring at room temperature for 48 h. After centrifugation and overnight drying at 110 °C, a light yellow blocky solid is obtained. The dried light yellow blocky solid is thoroughly ground to obtain cerium oxide with a particle size of 50-100 nm.

[0070] (2) The cerium oxide obtained in (1) was calcined at 500°C in air atmosphere for 4 hours to obtain pretreated cerium oxide.

[0071] (3) Weigh 33.5 mg PdCl2, add 2 mL of water and 1 mL of butanediamine to form a butanediamine solution, sonicate for 1 min until completely dissolved, and continue stirring the mixture for 2 h to obtain a palladium solution coordinated with butanediamine.

[0072] (4) 0.8 mL of the butanediamine-coordinated palladium solution obtained in (3) was added to 200 mg of the pretreated cerium oxide obtained in (2) at a rate of 0.2 mL / min. After aging at room temperature for 2 h, it was dried overnight at 80 °C. Finally, in order to reduce the metal nanoparticles, they were reduced at 300 °C (heating rate of 5 °C / min) for 2 h in a hydrogen-argon mixed atmosphere (volume ratio of hydrogen to argon is 1:9). After the reduction was completed, the reduced material was cooled to room temperature and then passivated at room temperature for 1 h in an oxygen-argon mixed atmosphere (volume ratio of oxygen to argon is 0.5:99.5) to obtain the cerium oxide supported palladium catalyst, which is the catalyst for the synthesis of cyclohexanone and its derivatives. The loading of chlorine was 1.8 wt% and the loading of palladium was 2.7 wt%.

[0073] 50 mg of the prepared catalyst was added to a high-temperature, high-pressure reactor containing 5 mL of deionized water, 0.5 mmol of guaiacol, and 10 µL of hydrochloric acid (36–38% by mass). Hydrogen gas was simultaneously introduced at 2 MPa, and the mixture was heated to 200 °C and reacted for 12 h. After the reaction was complete and the reactor cooled to room temperature, the inner wall of the reactor was rinsed with a large amount of deionized water, and the reaction solution was extracted multiple times with ethyl acetate. The liquid was collected, and hexadecane was added as an internal standard. Finally, qualitative and quantitative analysis of each component was performed using gas chromatography-mass spectrometry (GC-MS) and gas chromatography.

[0074] The results showed that the conversion rate of guaiacol was 99% and the selectivity of cyclohexanone was 90%.

[0075] Comparative Example 1 (1) Weigh 3.709 g of zirconium oxynitrate and add 160 mL of deionized water to dissolve it completely. Add 96 mL of ammonia water (mass concentration of 20~30%) dropwise and continue stirring at room temperature for 48 h. After centrifugation and drying at 110 °C overnight, a white blocky solid is obtained. The dried white solid is thoroughly ground to obtain zirconium oxide with a particle size of 10~30 nm.

[0076] (2) The obtained zirconium oxide was calcined at 500°C for 4 hours in air atmosphere to obtain pretreated zirconium oxide.

[0077] (3) Weigh 30 mg of palladium nitrate dihydrate, add 2 mL of water and 1 mL of ethylenediamine to form an ethylenediamine solution, sonicate for 1 min until completely dissolved, and continue stirring the mixture for 2 h to obtain a palladium salt solution.

[0078] (4) Weigh 200mg of the pretreated carrier obtained in (2), add 0.5mL of palladium salt solution dropwise to it while stirring continuously, continue aging at room temperature for 2h, transfer to an oven and dry at 80℃ overnight to obtain a completely dried solid powder. Reduce it for 2h in a hydrogen-argon mixed atmosphere (volume ratio of hydrogen to argon is 1:9) at 300℃. Cool the obtained reduced material to room temperature, and then passivate it for 0.5h in an oxygen-argon mixed atmosphere (volume ratio of oxygen to argon is 0.5:99.5) at room temperature to obtain a zirconium oxide supported palladium catalyst, wherein the palladium loading is 1wt%.

[0079] 50 mg of the prepared catalyst was added to a high-temperature, high-pressure reactor containing 5 mL of deionized water and 0.5 mmol of guaiacol, while hydrogen gas at 2 MPa was introduced. The temperature was raised to 240 °C and the reaction was carried out for 4 h. After the reaction was completed and the reactor was cooled to room temperature, the inner wall of the reactor was rinsed with a large amount of deionized water, and the reaction solution was extracted with ethyl acetate several times. The liquid was collected and hexadecane was added as an internal standard. Finally, the components were qualitatively and quantitatively analyzed by gas chromatography-mass spectrometry (GC-GC) and gas chromatography.

[0080] The results showed that the conversion rate of guaiacol was 99%, and the selectivity of cyclohexanone was approximately 40%.

[0081] Comparative Example 2 The difference from Example 3 is that butanediamine is not added in step (3), and the other operations are the same as in Example 3.

[0082] The results showed that the conversion rate of guaiacol was 69% and the selectivity of cyclohexanone was 45%.

[0083] Comparative Example 3 The difference from Example 3 is that hydrochloric acid is not added during the synthesis of cyclohexanone, while other operations are the same as in Example 3.

[0084] The results showed that the conversion rate of guaiacol was 82%, and the selectivity of cyclohexanone was 21%.

[0085] Comparative Example 4 The difference from Example 3 is that cerium oxide in step (1) is replaced with silicon dioxide, and other operations are the same as in Example 3.

[0086] The results showed that the conversion rate of guaiacol was 75%, and the selectivity of cyclohexanone was 35%.

[0087] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A catalyst for synthesizing cyclohexanone and its derivatives, characterized in that, The device includes a support, and palladium and chlorine loaded on the support; the support includes a molecular sieve or a metal oxide; the molecular sieve includes one or more of ZSM-5, SBA-15, and SAPO-34; the metal oxide includes zirconium oxide and / or cerium oxide. The palladium loading is 0.5~5wt%, and the chlorine loading is 0.1~2wt%.

2. The catalyst for synthesizing cyclohexanone and its derivatives according to claim 1, characterized in that, The silica-to-alumina ratio of the molecular sieve is 20-100.

3. The method for preparing the catalyst for the synthesis of cyclohexanone and its derivatives according to any one of claims 1 to 2, characterized in that, Includes the following steps: The carrier is pretreated to obtain a pretreated carrier; The pretreatment is calcination; Palladium salt, aliphatic diamine, and water were mixed to obtain a palladium salt coordination system; The pretreated support and palladium salt coordination system are mixed and then subjected to aging, drying, reduction and passivation in sequence to obtain the catalyst for synthesizing cyclohexanone and its derivatives. The palladium salt is a chlorinated palladium salt.

4. The preparation method according to claim 3, characterized in that, The calcination temperature is 500~550℃, the time is 2~24h, and the calcination atmosphere is air.

5. The preparation method according to claim 3, characterized in that, The palladium chloride salts include PdCl2, K2PdCl4, K2PdCl6, Pd(NH3)2Cl2, and C. 14 H 10 One or more of Cl2N2Pd; the aliphatic diamine is a water-soluble aliphatic diamine; The ratio of palladium salt to fatty diamine is 10-100 mg: 0.5-8 mL; The ratio of palladium salt to water is 10~100mg:1~10mL.

6. The preparation method according to claim 3, characterized in that, The ratio of the pretreatment carrier to the palladium salt coordination system is 50~500mg:0.1~2mL.

7. The preparation method according to claim 3, characterized in that, The aging time is 0.5~8h; the drying temperature is 50~120℃ and the time is 6~24h; the reduction temperature is 150~650℃ and the time is 0.5~6h, and the reduction atmosphere is a hydrogen-argon mixed atmosphere; the passivation time is 10~120min, and the passivation atmosphere is an oxygen-argon mixed system.

8. A method for synthesizing cyclohexanone and its derivatives, characterized in that, Includes the following steps: The catalyst, substrate, protic acid and solvent are mixed and then hydrogen gas is introduced to carry out the synthesis reaction to obtain the cyclohexanone and its derivatives. The catalyst is the catalyst for synthesizing cyclohexanone and its derivatives as described in any one of claims 1 to 2, or the catalyst for synthesizing cyclohexanone and its derivatives prepared by the preparation method described in any one of claims 3 to 7. The substrate is a methoxylated lignin phenol monomer, which includes one or more of 2-methoxyphenol, 4-propyl-2-methoxyphenol, 4-propyl-2,6-dimethoxyphenol, 4-propenyl-2-methoxyphenol, and 4-propenyl-2,6-dimethoxyphenol.

9. The synthesis method according to claim 8, characterized in that, The protic acid is an inorganic acid, including hydrochloric acid, sulfuric acid, or phosphoric acid; the mass concentration of the hydrochloric acid is 36-38%, the mass concentration of the sulfuric acid is 96-98%, and the mass concentration of the phosphoric acid is 83-95%. The catalyst to substrate ratio is 40-60 mg: 0.5 mmol; The ratio of substrate to protic acid is 0.5 mmol: 10~100 µL.

10. The synthesis method according to claim 8, characterized in that, The pressure of the hydrogen gas is 0.1~4MPa, the temperature of the synthesis reaction is 30~250℃, and the time is 0.5~15h.