阅读说明：本技术 用于缩合反应的催化剂及其制备方法 (Catalyst for condensation reaction and preparation method thereof ) 是由 李相呈 王振东 杨为民 刘闯 于 2019-10-25 设计创作，主要内容包括：本发明提供了一种用于缩合反应的催化剂,包括硫酸化或磺酸化的二氧化硅载体和活性组分,所述活性组分包括氧化铁和其他金属氧化物,所述其他金属氧化物选自锆的氧化物、锌的氧化物、铌的氧化物、钽的氧化物和铝的氧化物中的至少一种。本发明提供的催化剂制备方法简单、周期短、成本低,且催化剂对设备没有腐蚀性；催化效率高,产品产率高,反应结束后催化剂的分离简单,减少了分离能耗,且洗涤烘干后可重复使用。(The invention provides a catalyst for condensation reaction, which comprises a sulfated or sulfonated silica carrier and an active component, wherein the active component comprises ferric oxide and other metal oxides, and the other metal oxides are selected from at least one of zirconium oxide, zinc oxide, niobium oxide, tantalum oxide and aluminum oxide. The catalyst provided by the invention has the advantages of simple preparation method, short period and low cost, and the catalyst has no corrosivity to equipment; the catalyst has high catalytic efficiency and high product yield, the catalyst is simple to separate after the reaction is finished, the separation energy consumption is reduced, and the catalyst can be repeatedly used after being washed and dried.)

1. A catalyst for a condensation reaction comprising a sulphated or sulphonated silica support and an active component comprising iron oxide and a further metal oxide selected from at least one of zirconium oxide, zinc oxide, niobium oxide, tantalum oxide and aluminium oxide.

2. The catalyst of claim 1, wherein the catalyst has SO, calculated as silica₄ ^2-Or SO₃The molar ratio of H to ferric oxide, other metal oxides and silica carrier is as follows: (0.1-0.8): (0.10-0.30): (0.01-0.10): 1, preferably (0.2-0.5): (0.15-0.25): (0.04-0.08): 1.

3. the catalyst according to claim 1 or 2, characterized in that the acid amount of the catalyst is 308-963 μmol/g, preferably 510-790 μmol/g; and/or the specific surface area of the catalyst is 65 to 180m²A/g, preferably from 80 to 152m²/g。

4. A method of preparing a catalyst for a condensation reaction, comprising:

step A: mixing water, an iron source and other metal salts to obtain a solution I;

and B: mixing a silicon source with the solution I to obtain a solution II;

and C: mixing a sulfuric acid solution or a sulfonic acid solution with the solution II to obtain gel;

step D: after the gel is formed, roasting to obtain the catalyst,

wherein the other metal salt is at least one selected from the group consisting of zirconium salt, zinc salt, niobium salt, tantalum salt and aluminum salt, preferably zirconium salt and/or niobium salt.

5. The preparation method according to claim 4, wherein the iron source is selected from soluble salts of ferric iron or ferrous iron, preferably at least one selected from sulfate, nitrate and chloride, more preferably nitrate; and/or

The silicon source is selected from at least one of white carbon black, ethyl orthosilicate and silica sol, and is preferably ethyl orthosilicate; and/or

The water is deionized water; andor or

The sulfonic acid solution is C1-C6 alkyl sulfonic acid, preferably methyl sulfonic acid; and/or

In the sulfuric acid solution or the sulfonic acid solution, the volume ratio of the sulfuric acid or the sulfonic acid to the water is (0.5-2) to 1, preferably (0.8-1.2): 1.

6. the method according to claim 4 or 5, wherein the silicon source is silica, the iron source is iron, and the molar ratio of the sulfuric acid solution or the methanesulfonic acid solution to the silicon source is (0.1-0.8) to 1, preferably 0.2-0.5: 1; and/or the molar ratio of the iron source to the silicon source is (0.10-0.30) to 1, preferably (0.15-0.25) to 1; and/or the molar ratio of the further metal salt to the silicon source is from 0.01 to 0.10:1, preferably from 0.04 to 0.08: 1.

7. The method according to any one of claims 4-6, wherein the roasting temperature is 300-600 ℃, preferably 350-450 ℃; the roasting time is 1-6h, preferably 2-4 h.

8. A process for the catalytic self-condensation of cyclohexanone to 2- (1-cyclohexenyl) cyclohexanone, comprising contacting the catalyst according to any one of claims 1-3 or the catalyst obtained by the production process according to any one of claims 4-7 with cyclohexanone.

9. The method according to claim 8, characterized in that the amount of catalyst is 1-20%, preferably 5-15% of the mass of cyclohexanone;

and or the temperature of the contact is 100-150 ℃, preferably 110-130 ℃;

and/or the contact time is 2-6h, preferably 3-4 h.

10. The method according to claim 8 or 9, wherein the contacting is performed in a high pressure magnetic stirring reaction kettle, and the stirring speed is 200-1000 rpm, preferably 500-800 rpm.

Technical Field

The invention relates to the field of catalytic chemistry, in particular to a catalyst for condensation reaction and a preparation method thereof.

Background

2- (1-cyclohexenyl) cyclohexanone and its resonance isomer are important fine chemical products, can be used as broad-spectrum bactericide, preservative, etc., and its large-scale application is an important intermediate for synthesizing o-phenylphenol (OPP) by two-step method. The o-phenylphenol is an important organic chemical product, can be used as a sterilization preservative, a plastic stabilizer, a surfactant, a dye intermediate and the like, and has wide application in the chemical field. The synthesis method is a lot of, and the most widely applied method is cyclohexanone condensation dehydrogenation, and the specific process is that raw material cyclohexanone is self-condensed to generate 2- (1-cyclohexenyl) cyclohexanone and two dimers (shown in the following) of resonance isomers thereof, and then gas phase dehydrogenation is carried out to generate OPP.

The traditional synthesis method of cyclohexanone dimer is to use concentrated sulfuric acid, concentrated hydrochloric acid or methanesulfonic acid and other liquid acids as catalysts and to synthesize the cyclohexanone dimer through condensation and dehydration of two molecules of cyclohexanone. Although the conversion rate of the liquid acid is high, the liquid acid has the problems of serious equipment corrosion, large environmental pollution caused by alkali neutralization treatment of waste liquid, more side reactions and the like. Therefore, the development of an easily-separated, low-cost and environment-friendly solid catalyst for realizing green preparation of cyclohexanone dimer becomes a research focus at present.

Chenhong Yan et al (proceedings of Wuhan chemical institute of technology, 2002,24(4):6-8) adopt dealuminized ultrastable Y molecular sieve DUSY catalyst to catalyze cyclohexanone to condense and prepare 2- (1-cyclohexenyl) cyclohexanone. The cyclohexanone conversion rate is not described, the DUSY catalyst is relatively active, and the highest yield of the product dimer reaches 60% under the reaction condition of 138 ℃. However, as the reaction proceeded, the dimer yield did not increase, indicating that DUSY catalyst also promoted the cyclohexanone condensation side reaction. The by-products of cyclohexanone condensation are mainly polymers which are not industrially used and are difficult to degrade, which undoubtedly increases the energy consumption for separation and waste liquid treatment.

Chinese patent CN1535945A describes ion exchange resin catalyzed cyclohexanone condensation, the reaction process is simple, the product and the catalyst are easy to separate, but the dimer yield is only 75-85%. Bin (the college chemical engineering report, 2015, 2(29), 335-340) and the like use amination modified sulfonic acid type cation exchange resin as a solid catalyst, and the dimer selectivity is as high as 98.0% under the optimal reaction conditions. However, the preparation method of the catalyst is complex and has higher cost, and the preparation cost of the dimer is increased. The Mahajani group (ind. eng. chem. res.2008,47,25) uses various ion exchange resins as catalysts, and the selectivity of dimers can reach 93% at most. However, the ion exchange resin can not resist high temperature, and the reaction temperature is 100 ℃, so that the conversion rate of cyclohexanone is low, which is only 32%.

Buck et al (college reports on chemical engineering, 2015,4(29):866) prepared succinic acid intercalation S₂O₈ ^2-the/Mg-Al hydrotalcite catalyst has cyclohexanone conversion rate up to 86.7% and dimer selectivity up to 89.6% at 140 deg.c for 6 hr. But in the recycling process of the catalyst, the sulfur element on the surface of the catalyst is lost to a certain extent, and the catalytic activity is obviously reduced. Chinese patent CN104437558A adopts SO₄ ^2-·xLa³⁺·yCe³⁺/zZrO₂The solid super acid catalyzes the cyclohexanone condensation, the conversion rate of the cyclohexanone and the yield of dimer are high and reach 97 percent and 97.8 percent respectively, and SO is generated in the reaction process₄ ^2-The components are not easy to lose. But reactThe temperature is high and reaches 160 ℃, the energy consumption is high, and the process has no advantages. The catalyst shows good catalytic effect, but has the problems of low product selectivity, high catalyst preparation cost, overhigh reaction operation temperature, poor catalyst stability and the like. Therefore, it is very important to develop a solid acid catalyst with high activity, high selectivity and high stability for the cyclohexanone self-condensation reaction.

Disclosure of Invention

The invention aims to avoid the defects of the prior art and provide a catalyst for catalyzing the self-condensation of cyclohexanone to prepare 2- (1-cyclohexenyl) cyclohexanone. The inventor of the invention finds that the solid catalyst obtained by compounding ferric oxide serving as a main body and other metal oxides serving as auxiliaries has ideal cyclohexanone conversion rate and dimer selectivity under the intermittent operation condition.

In a first aspect, the present invention provides a catalyst for a condensation reaction comprising a sulphated or sulphonated silica support and an active component comprising iron oxide and a further metal oxide selected from at least one of zirconium oxide, zinc oxide, niobium oxide, tantalum oxide and aluminium oxide.

According to some embodiments of the invention, the catalyst comprises SO as silica₄ ^2-Or SO₃The molar ratio of H to ferric oxide, other metal oxides and silica carrier is as follows: (0.1-0.8): (0.10-0.30): (0.01-0.10): 1, preferably (0.2-0.5): (0.15-0.25): (0.04-0.08): 1.

according to some embodiments of the invention, the acid amount of the catalyst is 308-963. mu. mol/g.

According to a preferred embodiment of the invention, the acid amount of the catalyst is 510-790. mu. mol/g.

According to some embodiments of the invention, the catalyst has a specific surface area of 65 to 180m²/g。

According to a preferred embodiment of the invention, the specific surface area of the catalyst is between 80 and 152m²/g。

In a second aspect, the present invention provides a method of preparing a catalyst for a condensation reaction, comprising:

step A: mixing water, an iron source and other metal salts to obtain a solution I;

and B: mixing a silicon source with the solution I to obtain a solution II;

and C: mixing a sulfuric acid solution or a sulfonic acid solution with the solution II to obtain gel;

step D: after the gel is formed, roasting to obtain the catalyst,

wherein the other metal salt is at least one selected from the group consisting of zirconium salt, zinc salt, niobium salt, tantalum salt and aluminum salt.

According to a preferred embodiment of the invention, the further metal salt is a zirconium salt and/or a niobium salt.

According to some embodiments of the invention, the iron source is selected from soluble salts of ferric iron or ferrous iron.

According to some embodiments of the invention, the iron source is selected from at least one of sulphate, nitrate, chloride.

According to a preferred embodiment of the invention, the iron source is nitrate.

According to some embodiments of the invention, the silicon source is selected from at least one of white carbon, ethyl orthosilicate, and silica sol.

According to a preferred embodiment of the present invention, the silicon source is tetraethyl orthosilicate.

According to some embodiments of the invention, the water is deionized water.

According to a preferred embodiment of the invention, the water is deionized water.

According to some embodiments of the invention, the sulfonic acid solution is a C1-C6 alkyl sulfonic acid.

According to a preferred embodiment of the invention, the sulfonic acid solution is methanesulfonic acid.

According to some embodiments of the invention, the volume ratio of sulfuric acid or sulfonic acid to water in the sulfuric acid solution or sulfonic acid solution is (0.5-2): 1.

According to a preferred embodiment of the present invention, the volume ratio of sulfuric acid or sulfonic acid to water in the sulfuric acid solution or sulfonic acid solution is (0.8-1.2): 1.

according to some embodiments of the present invention, the molar ratio of the sulfuric acid solution or the methanesulfonic acid solution to the silicon source, based on silica, is (0.1-0.8): 1.

According to a preferred embodiment of the present invention, the silicon source is silica, and the molar ratio of the sulfuric acid solution or the methanesulfonic acid solution to the silicon source is 0.2-0.5: 1.

According to some embodiments of the invention, the silicon source is silica, the iron source is iron, and the molar ratio of the iron source to the silicon source is (0.10-0.30): 1.

According to a preferred embodiment of the present invention, the silicon source is silicon dioxide, the iron source is iron, and the molar ratio of the iron source to the silicon source is (0.15-0.25): 1.

According to some embodiments of the invention, the silicon source is silica and the molar ratio of the additional metal salt to the silicon source is 0.01-0.10: 1.

According to a preferred embodiment of the present invention, the molar ratio of the silicon source to the other metal salt is 0.04-0.08:1 calculated as silicon dioxide.

According to some embodiments of the present invention, the temperature of the calcination is 300-.

According to the preferred embodiment of the invention, the roasting temperature is 350-450 ℃ and the roasting time is 2-4 h.

According to some embodiments of the invention, the acid amount of the catalyst is 308-963. mu. mol/g.

According to a preferred embodiment of the invention, the acid amount of the catalyst is 510-790. mu. mol/g.

According to some embodiments of the invention, the catalyst has a specific surface area of 65 to 180m²/g。

According to a preferred embodiment of the invention, the specific surface area of the catalyst is between 80 and 152m²/g。

In a third aspect, the present invention provides a process for preparing 2- (1-cyclohexenyl) cyclohexanone by catalyzing the self-condensation of cyclohexanone, comprising contacting the catalyst according to the first aspect or the catalyst obtained by the preparation process according to the second aspect with cyclohexanone.

According to some embodiments of the invention, the catalyst is used in an amount of 1% to 20% of the mass of cyclohexanone.

According to a preferred embodiment of the invention, the catalyst is used in an amount of 5% to 15% by mass of cyclohexanone.

According to some embodiments of the invention, the contacting temperature is 100-.

According to a preferred embodiment of the invention, the temperature of the contacting is 110-.

According to some embodiments of the invention, the time of the contacting is 2 to 6 hours.

According to a preferred embodiment of the invention, the contact time is 3-4 h.

According to some embodiments of the invention, the contacting is performed in a high pressure magnetic stirring reaction vessel, and the stirring speed is 200 and 1000 revolutions per minute.

According to a preferred embodiment of the present invention, the stirring speed is 500-.

The invention has the beneficial technical effects that the solid acid catalyst is prepared by adopting a sol-gel method at low cost, the preparation method is simple, the period is short, the cost is low, and the catalyst has no corrosivity to equipment; the catalyst has high catalytic efficiency and high product yield, the catalyst is simple to separate after the reaction is finished, the separation energy consumption is reduced, and the catalyst can be repeatedly used after being washed and dried.

Drawings

FIG. 1 is a diagram of NH3-TPD of the solid acid catalyst prepared according to example 1.

Detailed Description

For the convenience of understanding the present invention, the present invention will be described below with reference to examples, which are only for the purpose of facilitating understanding of the present invention and should not be construed as specifically limiting the present invention.

In the present invention, the reaction product 2- (1-cyclohexenyl) cyclohexanone is analyzed and characterized by gas chromatography-mass spectrometry (GC-MS), and the yield of 2- (1-cyclohexenyl) cyclohexanone and the conversion of cyclohexanone are analyzed by Gas Chromatography (GC). The gas chromatograph-mass spectrometer is Agilent 7890A of Agilent, America, a chromatographic column is an HP-5 nonpolar capillary column (30m, 0.53mm), the gas chromatograph is Agilent 7890B, the detector is a hydrogen Flame Ionization Detector (FID), and the chromatographic column is an SE-54 capillary column (30m, 0.53 mm).

The formula for cyclohexanone conversion is:

conversion of cyclohexanone ═ molar amount of cyclohexanone participating in the reaction)/(molar amount of cyclohexanone as a reaction substrate) × 100%.

The yield of 2- (1-cyclohexenyl) cyclohexanone is calculated as:

the yield of 2- (1-cyclohexenyl) cyclohexanone was: (molar amount of 2- (1-cyclohexenyl) cyclohexanone produced by 2 × reaction)/(molar amount of cyclohexanone as a reaction substrate) × 100%.

The% selectivity of 2- (1-cyclohexenyl) cyclohexanone was (2 × molar amount of 2- (1-cyclohexenyl) cyclohexanone produced by the reaction)/(molar amount of cyclohexanone produced by the reaction) × 100%.

Example 1

Deionized water, 8.08g (0.02mol) Fe (NO)₃)₃·9H₂O and 2.15g (0.005mol) Zr (NO)₃)₄·5H₂Mixing O to form a uniform solution; 20.8g (0.1mol) of tetraethoxysilane is continuously and dropwise added into the solution, and after the mixture is uniformly stirred, 4.53g (0.03mol) of a sulfuric acid solution with the volume ratio of 1/1 is slowly and dropwise added. Heating and stirring the mixture under the condition of 50 ℃ water bath until the gel is completely formed, and then putting the gel into an oven to remove water and volatile matters. Finally, roasting the obtained dry precursor for 3 hours at 400 ℃ in a muffle furnace to obtain SO₄ ^2-/Fe₂O₃-ZrO₂-SiO₂A solid catalyst with an acid content of 570 mu mol/g and a specific surface area of 103m²/g。

The specific conditions for evaluating the reaction conditions were to place 2.0g of the prepared catalyst and 20g of cyclohexanone solution in a 100mL high pressure magnetic stirring reaction vessel, react at 130 ℃ for 3h, and gas phase analysis of the reaction solution resulted in a cyclohexanone conversion of 86.5% and a dimer selectivity of 99.4%.

Example 2

Deionized water, 8.08g (0.02mol) Fe (NO)₃)₃·9H₂O and 2.15g (0.005mol) Zr (NO)₃)₄·5H₂Mixing O to form a uniform solution; continuously dropwise adding 20.8g (0.1mol) of ethyl orthosilicate into the solution, and slowly dropwise adding 4.8g (0.03mol) of methanesulfonic acid solution with the volume ratio of 1/1 after uniformly stirring. Heating and stirring the mixture under the condition of 50 ℃ water bath until the gel is completely formed, and then putting the gel into an oven to remove water and volatile matters. Finally, roasting the obtained dry precursor for 3 hours at 400 ℃ in a muffle furnace to obtain-SO₃H/Fe₂O₃-ZrO₂-SiO₂Solid catalyst with acid content of 510 mu mol/g and specific surface area of 80m²/g。

The specific conditions for evaluating the reaction conditions were to place 2.0g of the prepared catalyst and 20g of cyclohexanone solution in a 100mL high pressure magnetic stirring reaction vessel, react at 130 ℃ for 3h, and gas phase analysis of the reaction solution resulted in a cyclohexanone conversion of 82.6% and a dimer selectivity of 99.2%.

Example 3

Deionized water, 4.04g (0.01mol) Fe (NO)₃)₃·9H₂O and 3.44g (0.008mol) Zr (NO)₃)₄·5H₂Mixing O to form a uniform solution; 20.8g (0.1mol) of tetraethoxysilane is continuously and dropwise added into the solution, and after the mixture is uniformly stirred, 6.04g (0.04mol) of sulfuric acid solution with the volume ratio of 1/1 is slowly and dropwise added. Heating and stirring the mixture under the condition of 50 ℃ water bath until the gel is completely formed, and then putting the gel into an oven to remove water and volatile matters. Finally, roasting the obtained dry precursor for 3 hours at 400 ℃ in a muffle furnace to obtain SO₄ ^2-/Fe₂O₃-ZrO₂-SiO₂A solid catalyst, the acid content of which is 607 [ mu ] mol/g, the specific surface area of which is 97m²/g。

The specific conditions for evaluating the reaction conditions were to place 2.0g of the prepared catalyst and 20g of cyclohexanone solution in a 100mL high pressure magnetic stirring reaction vessel, react at 120 ℃ for 4h, and gas phase analysis of the reaction solution was performed to obtain a cyclohexanone conversion of 89.3% and a dimer selectivity of 98.7%.

Example 4

Deionized water, 4.04g (0.01mol) Fe (NO)₃)₃·9H₂O and 3.44g (0.008mol) Zr (NO)₃)₄·5H₂Mixing O to form a uniform solution; continuously dropwise adding 20.8g (0.1mol) of ethyl orthosilicate into the solution, and slowly dropwise adding 6.4g (0.04mol) of methanesulfonic acid solution with the volume ratio of 1/1 after uniformly stirring. Heating and stirring the mixture under the condition of 50 ℃ water bath until the gel is completely formed, and then putting the gel into an oven to remove water and volatile matters. Finally, roasting the obtained dry precursor for 3 hours at 400 ℃ in a muffle furnace to obtain-SO₃H/Fe₂O₃-ZrO₂-SiO₂The solid catalyst has an acid content of 534 mu mol/g and a specific surface area of 85m²/g。

The specific conditions for evaluating the reaction conditions were to place 2.0g of the prepared catalyst and 20g of cyclohexanone solution in a 100mL high pressure magnetic stirred tank reactor, react at 120 ℃ for 4h, and gas phase analysis of the reaction solution resulted in a cyclohexanone conversion of 86.5% and a dimer selectivity of 99.3%.

Example 5

Deionized water, 1.20g (0.03mol) Fe₂(SO₄)₃And 2.15g (0.005mol) Zr (NO)₃)₄·5H₂Mixing O to form a uniform solution; 20.8g (0.1mol) of tetraethoxysilane is continuously and dropwise added into the solution, and 7.55g (0.05mol) of sulfuric acid solution with the volume ratio of 1/1 is slowly and dropwise added after the solution is uniformly stirred. Heating and stirring the mixture under the condition of 50 ℃ water bath until the gel is completely formed, and then putting the gel into an oven to remove water and volatile matters. Finally, roasting the obtained dry precursor for 3 hours at 400 ℃ in a muffle furnace to obtain SO₄ ^2-/Fe₂O₃-ZrO₂-SiO₂A solid catalyst with an acid content of 790 mu mol/g and a specific surface area of 131m²/g。

The specific conditions for evaluating the reaction conditions were to place 2.0g of the prepared catalyst and 20g of cyclohexanone solution in a 100mL high pressure magnetic stirring reaction vessel, react at 130 ℃ for 3h, and gas phase analysis of the reaction solution resulted in a cyclohexanone conversion of 95.3% and a dimer selectivity of 98.2%.

Example 6

Deionized water, 1.20g (0.03mol) Fe (NO)₃)₃·9H₂O and 2.15g (0.005mol) Zr (NO)₃)₄·5H₂Mixing O to form a uniform solution; continuously dropwise adding 20.8g (0.1mol) of ethyl orthosilicate into the solution, and slowly dropwise adding 8.1g (0.05mol) of methanesulfonic acid solution with the volume ratio of 1/1 after uniformly stirring. Heating and stirring the mixture under the condition of 50 ℃ water bath until the gel is completely formed, and then putting the gel into an oven to remove water and volatile matters. Finally, roasting the obtained dry precursor for 3 hours at 400 ℃ in a muffle furnace to obtain-SO₃H/Fe₂O₃-ZrO₂-SiO₂A solid catalyst with an acid content of 584 [ mu ] mol/g and a specific surface area of 96m²/g。

The specific conditions for evaluating the reaction conditions were to place 2.0g of the prepared catalyst and 20g of cyclohexanone solution in a 100mL high pressure magnetic stirred tank reactor, react at 120 ℃ for 4h, and gas phase analysis of the reaction solution was performed to obtain a cyclohexanone conversion of 88.4% and a dimer selectivity of 98.8%.

Example 7

Deionized water, 6.06g (0.015mol) Fe (NO)₃)₃·9H₂O and 1.31g (0.004mol) of zirconium acetate were mixed to form a homogeneous solution; continuously dropwise adding 20.8g (0.1mol) of tetraethoxysilane into the solution, and slowly dropwise adding 3.0g (0.02mol) of a sulfuric acid solution with the volume ratio of 1/1 after uniformly stirring. Heating and stirring the mixture under the condition of 50 ℃ water bath until the gel is completely formed, and then putting the gel into an oven to remove water and volatile matters. Finally, roasting the obtained dry precursor for 4 hours at 400 ℃ in a muffle furnace to obtain SO₄ ^2-/Fe₂O₃-ZrO₂-SiO₂The solid catalyst has an acid content of 416 mu mol/g and a specific surface area of 86m²/g。

The specific conditions for evaluating the reaction conditions were to place 2.0g of the prepared catalyst and 20g of cyclohexanone solution in a 100mL high pressure magnetic stirring reaction vessel, react at 130 ℃ for 4h, and gas phase analysis of the reaction solution gave a cyclohexanone conversion of 81.1% and a dimer selectivity of 97.3%.

Example 8

Deionized water, 6.06g (0.015mol) Fe (NO)₃)₃·9H₂O and 1.31g (0.004mol) of zirconium acetate were mixed to form a homogeneous solution; continuously dropwise adding 20.8g (0.1mol) of ethyl orthosilicate into the solution, and slowly dropwise adding 3.2g (0.02mol) of methanesulfonic acid solution with the volume ratio of 1/1 after uniformly stirring. Heating and stirring the mixture under the condition of 50 ℃ water bath until the gel is completely formed, and then putting the gel into an oven to remove water and volatile matters. Finally, roasting the obtained dry precursor for 3 hours at 400 ℃ in a muffle furnace to obtain-SO₃H/Fe₂O₃-ZrO₂-SiO₂A solid catalyst with acid content of 328 mu mol/g and specific surface area of 65m²/g。

The specific conditions for evaluating the reaction conditions were to place 2.0g of the prepared catalyst and 20g of cyclohexanone solution in a 100mL high pressure magnetic stirring reaction vessel, react at 130 ℃ for 4h, and gas phase analysis of the reaction solution resulted in a cyclohexanone conversion of 67.9% and a dimer selectivity of 96.8%.

Example 9

Deionized water, 8.0g (0.02mol) Fe₂(SO₄)₃And 1.5g (0.005mol) Zn (NO)₃)₂·6H₂Mixing O to form a uniform solution; continuously dropwise adding 20.8g (0.1mol) of ethyl orthosilicate into the solution, and slowly dropwise adding 12.1g (0.08mol) of sulfuric acid solution with the volume ratio of 1/1 after uniformly stirring. Heating and stirring the mixture under the condition of 50 ℃ water bath until the gel is completely formed, and then putting the gel into an oven to remove water and volatile matters. Finally, roasting the obtained dry precursor for 3 hours at 400 ℃ in a muffle furnace to obtain SO₄ ^2-/Fe₂O₃-ZnO-SiO₂Solid catalyst with acid content of 920 mu mol/g and specific surface area of 164m²/g。

The specific conditions for evaluating the reaction conditions were to place 2.0g of the prepared catalyst and 40g of cyclohexanone solution in a 100mL high pressure magnetic stirred tank reactor, react at 110 ℃ for 4h, and gas phase analysis of the reaction solution was performed to obtain a cyclohexanone conversion of 93.3% and a dimer selectivity of 92.8%.

Example 10

Deionized water, 8.0g (0.02mol) Fe₂(SO₄)₃And 1.5g (0.005mol) Zn (NO)₃)₂·6H₂Mixing O to form a uniform solution; continuously dropwise adding 20.8g (0.1mol) of ethyl orthosilicate into the solution, and slowly dropwise adding 12.9g (0.08mol) of methanesulfonic acid solution with the volume ratio of 1/1 after uniformly stirring. Heating and stirring the mixture under the condition of 50 ℃ water bath until the gel is completely formed, and then putting the gel into an oven to remove water and volatile matters. Finally, roasting the obtained dry precursor for 3 hours at 400 ℃ in a muffle furnace to obtain-SO₃H/Fe₂O₃-ZnO-SiO₂A solid catalyst with an acid content of 760. mu. mol/g and a specific surface area of 109m²/g。

The specific conditions for evaluating the reaction conditions were to place 2.0g of the prepared catalyst and 40g of cyclohexanone solution in a 100mL high pressure magnetic stirring reaction vessel, react at 110 ℃ for 4h, and gas phase analysis of the reaction solution was performed to obtain a cyclohexanone conversion of 90.8% and a dimer selectivity of 92.1%.

Example 11

Deionized water, 8.08g (0.02mol) Fe (NO)₃)₃·9H₂O and 6mL of 1mol/L niobium tartrate (0.006mol) are mixed to form a uniform solution; continuously dropwise adding 20.8g (0.1mol) of tetraethoxysilane into the solution, and slowly dropwise adding 3.0g (0.02mol) of a sulfuric acid solution with the volume ratio of 1/1 after uniformly stirring. Heating and stirring the mixture under the condition of 50 ℃ water bath until the gel is completely formed, and then putting the gel into an oven to remove water and volatile matters. Finally, roasting the obtained dry precursor for 3 hours at 400 ℃ in a muffle furnace to obtain SO₄ ^2-/Fe₂O₃-Nb₂O₅-SiO₂A solid catalyst with an acid content of 572 mu mol/g and a specific surface area of 105m²/g。

The specific conditions for evaluating the reaction conditions were to place 2.0g of the prepared catalyst and 20g of cyclohexanone solution in a 100mL high pressure magnetic stirring reaction vessel, react at 130 ℃ for 3h, and gas phase analysis of the reaction solution resulted in a cyclohexanone conversion of 82.8% and a dimer selectivity of 99.1%.

Example 12

Deionized water, 8.08g (0.02mol) Fe (NO)₃)₃·9H₂O and 6mL of 1mol/L niobium tartrate (0.006mol) are mixed to form a uniform solution; continuously dropwise adding 20.8g (0.1mol) of ethyl orthosilicate into the solution, and slowly dropwise adding 3.2g (0.02mol) of methanesulfonic acid solution with the volume ratio of 1/1 after uniformly stirring. Heating and stirring the mixture under the condition of 50 ℃ water bath until the gel is completely formed, and then putting the gel into an oven to remove water and volatile matters. Finally, roasting the obtained dry precursor for 3 hours at 400 ℃ in a muffle furnace to obtain-SO₃H/Fe₂O₃-Nb₂O₅-SiO₂Solid catalyst with acid content of 475 mu mol/g and specific surface area of 116m²/g。

The specific conditions for evaluating the reaction conditions were to place 2.0g of the prepared catalyst and 20g of cyclohexanone solution in a 100mL high pressure magnetic stirring reaction vessel, react at 130 ℃ for 3h, and gas phase analysis of the reaction solution gave a cyclohexanone conversion of 79.7% and a dimer selectivity of 96.3%.

Example 13

Deionized water, 4.04g (0.010mol) Fe (NO)₃)₃·9H₂O and 10mL of 1mol/L niobium tartrate (0.01mol) are mixed to form a uniform solution; continuously dropwise adding 20.8g (0.1mol) of tetraethoxysilane into the solution, and slowly dropwise adding 3.0g (0.02mol) of a sulfuric acid solution with the volume ratio of 1/1 after uniformly stirring. Heating and stirring the mixture under the condition of 50 ℃ water bath until the gel is completely formed, and then putting the gel into an oven to remove water and volatile matters. Finally, roasting the obtained dry precursor for 3 hours at 400 ℃ in a muffle furnace to obtain SO₄ ^2-/Fe₂O₃-Nb₂O₅-SiO₂A solid catalyst with an acid content of 508 [ mu ] mol/g and a specific surface area of 95m²/g。

The specific conditions for evaluating the reaction conditions were to place 2.0g of the prepared catalyst and 20g of cyclohexanone solution in a 100mL high pressure magnetic stirred tank reactor, react at 150 ℃ for 4h, and gas phase analysis of the reaction solution resulted in a cyclohexanone conversion of 80.2% and a dimer selectivity of 95.7%.

Example 14

Will go toIonized water, 4.04g (0.010mol) Fe (NO)₃)₃·9H₂O and 10mL of 1mol/L niobium tartrate (0.01mol) are mixed to form a uniform solution; continuously dropwise adding 20.8g (0.1mol) of ethyl orthosilicate into the solution, and slowly dropwise adding 3.2g (0.02mol) of methanesulfonic acid solution with the volume ratio of 1/1 after uniformly stirring. Heating and stirring the mixture under the condition of 50 ℃ water bath until the gel is completely formed, and then putting the gel into an oven to remove water and volatile matters. Finally, roasting the obtained dry precursor for 3 hours at 400 ℃ in a muffle furnace to obtain-SO₃H/Fe₂O₃-Nb₂O₅-SiO₂Solid catalyst with acid content of 459 mu mol/g and specific surface area of 86m²/g。

The specific conditions for evaluating the reaction conditions were to place 2.0g of the prepared catalyst and 20g of cyclohexanone solution in a 100mL high pressure magnetic stirred tank reactor, react at 150 ℃ for 4h, and gas phase analysis of the reaction solution was performed to obtain a cyclohexanone conversion of 73.5% and a dimer selectivity of 94.6%.

Example 15

Deionized water, 6.0g (0.015mol) Fe₂(SO₄)₃And 1.86g (0.005mol) Al (NO)₃)₃·9H₂Mixing O to form a uniform solution; 20.8g (0.1mol) of tetraethoxysilane is continuously and dropwise added into the solution, and 7.6g (0.05mol) of sulfuric acid solution with the volume ratio of 1/1 is slowly and dropwise added after the solution is uniformly stirred. Heating and stirring the mixture under the condition of 50 ℃ water bath until the gel is completely formed, and then putting the gel into an oven to remove water and volatile matters. Finally, roasting the obtained dry precursor for 3 hours at 400 ℃ in a muffle furnace to obtain SO₄ ^2-/Fe₂O₃-Al₂O₃-SiO₂The solid catalyst has an acid content of 543 mu mol/g and a specific surface area of 152m²/g。

The specific conditions for evaluating the reaction conditions were to place 2.0g of the prepared catalyst and 30g of cyclohexanone solution in a 100mL high pressure magnetic stirring reaction vessel, react at 130 ℃ for 4h, and gas phase analysis of the reaction solution resulted in a cyclohexanone conversion of 83.4% and a dimer selectivity of 99.2%.

Example 16

Deionized water, 6.0g (0.015mol) Fe₂(SO₄)₃And 1.86g (0.005mol) Al (NO)₃)₃·9H₂Mixing O to form a uniform solution; continuously dropwise adding 20.8g (0.1mol) of ethyl orthosilicate into the solution, and slowly dropwise adding 8.0g (0.05mol) of methanesulfonic acid solution with the volume ratio of 1/1 after uniformly stirring. Heating and stirring the mixture under the condition of 50 ℃ water bath until the gel is completely formed, and then putting the gel into an oven to remove water and volatile matters. Finally, roasting the obtained dry precursor for 3 hours at 400 ℃ in a muffle furnace to obtain-SO₃H/Fe₂O₃-Al₂O₃-SiO₂The solid catalyst has an acid content of 483 [ mu ] mol/g and a specific surface area of 123m²/g。

The specific conditions for evaluating the reaction conditions were to place 2.0g of the prepared catalyst and 30g of cyclohexanone solution in a 100mL high pressure magnetic stirring reaction vessel, react at 130 ℃ for 4h, and gas phase analysis of the reaction solution resulted in a cyclohexanone conversion of 77.2% and a dimer selectivity of 95.1%.

Example 17

The catalyst prepared in example 1 is washed, dried and put into the next reaction for 5 times of reaction. The specific conditions for evaluating the reaction conditions were 2.0g of the prepared catalyst and 20g of cyclohexanone solution were charged into a 100mL high-pressure magnetic stirring reaction vessel and reacted at 130 ℃ for 3 hours, the reaction results of each time are shown in Table 1, and it can be seen that the SO was present₄ ^2-/Fe₂O₃-ZrO₂-SiO₂The solid catalyst shows good circulation stability.

TABLE 1 Cyclohexanone conversion and dimer yield under catalyst recycle conditions

Number of times of application	Conversion of cyclohexanone/%	Dimer yield/%
			1	86.5	99.4
2	86.2	99.2
			3	85.7	99.2
4	85.4	98.7
			5	85.5	98.6

Example 18

Deionized water, 8.08g (0.02mol) Fe (NO)₃)₃·9H₂O and 2.15g (0.005mol) Zr (NO)₃)₄·5H₂Mixing O to form a uniform solution; 20.8g (0.1mol) of tetraethoxysilane is continuously and dropwise added into the solution, and after the mixture is uniformly stirred, 0.755g (0.005mol) of a sulfuric acid solution with the volume ratio of 1/1 is slowly and dropwise added. Heating and stirring the mixture under the condition of 50 ℃ water bath until the gel is completely formed, and then putting the gel into an oven to remove water and volatile matters. Finally, roasting the obtained dry precursor for 3 hours at 400 ℃ in a muffle furnace to obtain SO₄ ^2-/Fe₂O₃-ZrO₂-SiO₂Solid catalyst with acid content of 358 mu mol/g and specific surface area of 108m²/g。

The specific conditions for evaluating the reaction conditions were to place 2.0g of the prepared catalyst and 20g of cyclohexanone solution in a 100mL high pressure magnetic stirring reaction vessel, react at 130 ℃ for 3h, and gas phase analysis of the reaction solution resulted in a cyclohexanone conversion of 67.2% and a dimer selectivity of 96.7%.

Example 19

Deionized water, 8.08g (0.02mol) Fe (NO)₃)₃·9H₂O and 2.15g (0.005mol) Zr (NO)₃)₄·5H₂Mixing O to form a uniform solution; continuously dropwise adding 20.8g (0.1mol) of tetraethoxysilane into the solution, and slowly dropwise adding 15.1g (0.1mol) of a sulfuric acid solution with the volume ratio of 1/1 after uniformly stirring. Heating and stirring the mixture under the condition of 50 ℃ water bath until the gel is completely formed, and then putting the gel into an oven to remove water and volatile matters. Finally, roasting the obtained dry precursor for 3 hours at 400 ℃ in a muffle furnace to obtain SO₄ ^2-/Fe₂O₃-ZrO₂-SiO₂Solid catalyst with acid content of 963 mu mol/g and specific surface area of 84m²/g。

The specific conditions for evaluating the reaction conditions were to place 2.0g of the prepared catalyst and 20g of cyclohexanone solution in a 100mL high pressure magnetic stirring reaction vessel, react at 130 ℃ for 3h, and gas phase analysis of the reaction solution resulted in a cyclohexanone conversion of 97.7% and a dimer selectivity of 93.5%.

Example 20

Deionized water, 2.02g (0.005mol) Fe (NO)₃)₃·9H₂O and 2.15g (0.005mol) Zr (NO)₃)₄·5H₂Mixing O to form a uniform solution; 20.8g (0.1mol) of tetraethoxysilane is continuously and dropwise added into the solution, and after the mixture is uniformly stirred, 4.53g (0.03mol) of a sulfuric acid solution with the volume ratio of 1/1 is slowly and dropwise added. Heating and stirring the mixture under the condition of 50 ℃ water bath until the gel is completely formed, and then putting the gel into an oven to remove water and volatile matters. Finally, roasting the obtained dry precursor for 3 hours at 400 ℃ in a muffle furnace to obtain SO₄ ^2-/Fe₂O₃-ZrO₂-SiO₂Solid catalyst with acid content of 530 mu mol/g and specific surface area of 109m²/g。

The specific conditions for evaluating the reaction conditions were to place 2.0g of the prepared catalyst and 20g of cyclohexanone solution in a 100mL high pressure magnetic stirring reaction vessel, react at 130 ℃ for 3h, and gas phase analysis of the reaction solution gave a cyclohexanone conversion of 81.3% and a dimer selectivity of 95.7%.

Example 21

Deionized water, 8.08g (0.02mol) Fe (NO)₃)₃·9H₂O and 0.43g (0.001mol) Zr (NO)₃)₄·5H₂Mixing O to form a uniform solution; 20.8g (0.1mol) of tetraethoxysilane is continuously and dropwise added into the solution, and after the mixture is uniformly stirred, 4.53g (0.03mol) of a sulfuric acid solution with the volume ratio of 1/1 is slowly and dropwise added. Heating and stirring the mixture under the condition of 50 ℃ water bath until the gel is completely formed, and then putting the gel into an oven to remove water and volatile matters. Finally, roasting the obtained dry precursor for 3 hours at 400 ℃ in a muffle furnace to obtain SO₄ ^2-/Fe₂O₃-ZrO₂-SiO₂The solid catalyst has an acid content of 542 mu mol/g and a specific surface area of 101m²/g。

The specific conditions for evaluating the reaction conditions were to place 2.0g of the prepared catalyst and 20g of cyclohexanone solution in a 100mL high pressure magnetic stirring reaction vessel, react at 130 ℃ for 3h, and gas phase analysis of the reaction solution resulted in a cyclohexanone conversion of 83.6% and a dimer selectivity of 97.2%.

Example 22

Deionized water, 8.08g (0.02mol) Fe (NO)₃)₃·9H₂O and 4.3g (0.01mol) Zr (NO)₃)₄·5H₂Mixing O to form a uniform solution; 20.8g (0.1mol) of tetraethoxysilane is continuously and dropwise added into the solution, and after the mixture is uniformly stirred, 4.53g (0.03mol) of a sulfuric acid solution with the volume ratio of 1/1 is slowly and dropwise added. Heating and stirring the mixture under the condition of 50 ℃ water bath until the gel is completely formed, and then putting the gel into an oven to remove water and volatile matters. Finally, roasting the obtained dry precursor for 3 hours at 400 ℃ in a muffle furnace to obtain SO₄ ^2-/Fe₂O₃-ZrO₂-SiO₂The solid catalyst has an acid content of 641 mu mol/g and a specific surface area of 92m²/g。

The specific conditions for evaluating the reaction conditions were to place 2.0g of the prepared catalyst and 20g of cyclohexanone solution in a 100mL high pressure magnetic stirring reaction vessel, react at 130 ℃ for 3h, and gas phase analysis of the reaction solution was performed to obtain a cyclohexanone conversion of 90.7% and a dimer selectivity of 96.3%.

Comparative example 1

SO is prepared by the method described in Chinese patent CN104437558A₄ ^2-·xLa³⁺·yCe³⁺/zZrO₂A solid catalyst. First 1g La (NO)₃)₃·6H₂O、1g Ce(NO₃)₃·6H₂O、100(NH₄)₂SO₄Dissolved in deionized water, and then 10g of nano ZrO was added₂Soaking at 20 deg.C for 36h, drying to anhydrous, calcining at 550 deg.C for 5h to obtain SO₄ ^2-·xLa³⁺·yCe³⁺/zZrO₂The solid catalyst has an acid content of 286 mu mol/g and a specific surface area of 273m²/g。

The specific conditions for evaluating the reaction conditions were to place 2.0g of the prepared catalyst and 20g of cyclohexanone solution in a 100mL high pressure magnetic stirring reaction vessel, react at 130 ℃ for 3h, and gas phase analysis of the reaction solution resulted in a cyclohexanone conversion of 62.5% and a dimer selectivity of 91.8%.

Comparative example 2

Preparing Fe by adopting an isometric impregnation method₂O₃-ZrO₂a/ZSM-5 catalyst. First, deionized water, 8.08g (0.02mol) Fe (NO)₃)₃·9H₂O and 2.15g (0.005mol) Zr (NO)₃)₄·5H₂O mixed to form a homogeneous solution. 6.0g of ZSM-5 powder was weighed, added to the above homogeneous solution, and stirred until mixed uniformly. And continuously dropwise adding deionized water, continuously stirring to a primary wet state, and drying in a low-temperature oven. Finally, roasting the obtained dry precursor for 3 hours at 400 ℃ in a muffle furnace to obtain Fe₂O₃-ZrO₂a/ZSM-5 catalyst. The acid amount was 473. mu. mol/g, the specific surface area was 183m²/g。

The specific conditions for evaluating the reaction conditions were to place 2.0g of the prepared catalyst and 20g of cyclohexanone solution in a 100mL high pressure magnetic stirring reaction vessel, react at 130 ℃ for 3h, and gas phase analysis of the reaction solution resulted in a cyclohexanone conversion of 72.8% and a dimer selectivity of 90.2%.

Comparative example 3

Deionized water, 2.15g (0.005mol) Zr (NO)₃)₄·5H₂Mixing O to form a uniform solution; 20.8g (0.1mol) of tetraethoxysilane is continuously and dropwise added into the solution, and after the mixture is uniformly stirred, 4.53g (0.03mol) of a sulfuric acid solution with the volume ratio of 1/1 is slowly and dropwise added. Heating and stirring the mixture under the condition of 50 ℃ water bath until the gel is completely formed, and then putting the gel into an oven to remove water and volatile matters. Finally, roasting the obtained dry precursor for 3 hours at 400 ℃ in a muffle furnace to obtain SO₄ ^2-/ZrO₂-SiO₂A solid catalyst with an acid content of 490 [ mu ] mol/g and a specific surface area of 89m²/g。

The specific conditions for evaluating the reaction conditions were to place 2.0g of the prepared catalyst and 20g of cyclohexanone solution in a 100mL high pressure magnetic stirred tank reactor, react at 130 ℃ for 3h, and gas phase analysis of the reaction solution resulted in a cyclohexanone conversion of 73.5% and a dimer selectivity of 86.4%.

Comparative example 4

Deionized water, 8.08g (0.02mol) Fe (NO)₃)₃·9H₂O and 2.15g (0.005mol) Zr (NO)₃)₄·5H₂Mixing O to form a uniform solution; to the above solution was continuously added dropwise 20.8g (0.1mol) of ethyl orthosilicate. Heating and stirring the mixture under the condition of 50 ℃ water bath until the gel is completely formed, and then putting the gel into an oven to remove water and volatile matters. Finally, roasting the obtained dry precursor for 3 hours at 400 ℃ in a muffle furnace to obtain Fe₂O₃-ZrO₂-SiO₂Solid catalyst, acid content 260 mu mol/g, specific surface area 157m²/g。

The specific conditions for evaluating the reaction conditions were to place 2.0g of the prepared catalyst and 20g of cyclohexanone solution in a 100mL high pressure magnetic stirring reaction vessel, react at 130 ℃ for 3h, and gas phase analysis of the reaction solution resulted in a cyclohexanone conversion of 35.4% and a dimer selectivity of 88.1%.

Comparative example 5

Deionized water, 8.08g (0.02mol) Fe (NO)₃)₃·9H₂Mixing O to form a uniform solution; 20.8g (0.1mol) of tetraethoxysilane is continuously and dropwise added into the solution, and after the mixture is uniformly stirred, 4.53g (0.03mol) of a sulfuric acid solution with the volume ratio of 1/1 is slowly and dropwise added. Heating and stirring the mixture under the condition of 50 ℃ water bath until the gel is completely formed, and then putting the gel into an oven to remove water and volatile matters. Finally, roasting the obtained dry precursor for 3 hours at 400 ℃ in a muffle furnace to obtain SO₄ ^2-/Fe₂O₃-SiO₂Solid catalyst, acid content 527. mu. mol/g, specific surface area 96m²/g。

The specific conditions for evaluating the reaction conditions were to place 2.0g of the prepared catalyst and 20g of cyclohexanone solution in a 100mL high pressure magnetic stirring reaction vessel, react at 130 ℃ for 3h, and gas phase analysis of the reaction solution resulted in a cyclohexanone conversion of 80.3% and a dimer selectivity of 93.7%.

It should be noted that the above-mentioned embodiments are only for explaining the present invention, and do not constitute any limitation to the present invention. The present invention has been described with reference to exemplary embodiments, but the words which have been used herein are words of description and illustration, rather than words of limitation. The invention can be modified, as prescribed, within the scope of the claims and without departing from the scope and spirit of the invention. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, but rather extends to all other methods and applications having the same functionality.