CN115970741A - ZSM-5 molecular sieve catalyst and preparation method and application thereof - Google Patents

Abstract

The invention provides a ZSM-5 molecular sieve catalyst and a preparation method and application thereof, wherein the ZSM-5 molecular sieve catalyst is prepared by taking an alkaline ionic liquid as a template agent and adopting a hydrothermal crystallization method, wherein the alkaline ionic liquid template agent is imidazole ionic liquid and tetrabutylammonium ionic liquid, the ionic liquid is prepared by taking brominated 1, 3-dialkyl imidazolium salt or quaternary ammonium salt as a cation and combining different anions, a silicon source, an aluminum source, an alkali source and water are taken as raw materials, and the hydrogen type ZSM-5 molecular sieve is obtained by three steps of preparation of the template agent, preparation of a reaction mixture and hydrothermal crystallization, solid-liquid separation, washing, ion exchange, drying and roasting. The preparation process is simple, the acid sites of the catalyst are adjustable, and the obtained product has good hydrothermal stability, high activity and good effect, so that the conversion rate of cyclohexene is high, the selectivity of cyclohexanol is good, the used raw materials are safe, the process is simple, and the method can be used for industrial production.

Description

ZSM-5 molecular sieve catalyst and its preparation method and application

technical field

The invention belongs to the technical field of preparation of molecular sieve catalysts, in particular, relates to a ZSM-5 molecular sieve catalyst and its preparation method and application, in particular to a method and application of a ZSM-5 molecular sieve prepared with an alkaline ionic liquid as a template.

Background technique

Cyclohexanol is an important chemical intermediate, mainly used as an intermediate raw material for the production of adipic acid, ammonium caprolactam and nylon. Currently, there are three methods for producing cyclohexanol: cyclohexane oxidation, phenol hydrogenation and cyclohexene direct hydration. Among them, there are mainly four types of catalysts used in the direct hydration of cyclohexene, namely inorganic acids and their salts, acid oxides, heteropolyacids, and ion exchange resins. Among them, inorganic acid catalysts, such as sulfuric acid, were used earlier, but the process consumes a lot of energy, the product is difficult to separate, and there are defects such as corrosion of equipment by sulfuric acid. Ion exchange resin is widely used in the hydration reaction of cyclohexanol because of its strong acidity. Different ion exchange resins provide different types and strengths of acid centers, and have different effects on the reaction. Lin Qingxiang from Zhejiang University investigated the catalytic performance of seven different ion exchange resins, and the results showed that the strongly acidic cation exchange resins Amberlyst36wet, Amberlyst35wet and ZGC107 had higher catalytic activities. Compared with inorganic acid catalysts, ion exchange resins solve the problems of product recovery and the like, but their inherent disadvantages of poor thermal stability, easy deactivation, and short life limit their further industrial applications.

Japan's Asahi Kasei Corporation developed Ru and HZSM-5 catalysts in the 1980s, and used them in the hydrogenation of phenol to cyclohexene and the hydration of cyclohexene to cyclohexanol, and in 1983 applied for the use of solid acid molecular sieves to catalyze cyclohexanol. Hexene hydration process patent. Because zeolite molecular sieve materials have suitable acidity, high mechanical strength and good thermal stability, they have been the research focus of olefin hydration catalysts in recent years. Studies have shown that factors such as grain size, acidity and crystallinity of molecular sieves have a great influence on its structure and performance. Zhang et al. studied the hydration reaction process of cyclohexene catalyzed by zeolite. The results showed that when the SiO ₂ /Al ₂ O ₃ ratio of ZSM-5 zeolite molecules is 30-50, the selectivity of cyclohexanol can reach 99%, and the catalytic activity is the best. . However, the hydration of cyclohexene to cyclohexanol is limited by the chemical balance, resulting in a low single-pass conversion of cyclohexene (7-10%), and the process has problems such as large circulation volume and high energy consumption.

Therefore, it is necessary to find a new type of catalyst to break the chemical balance of the traditional process and improve the conversion rate of cyclohexanol prepared by cyclohexene hydration.

Contents of the invention

In order to solve the problems of low conversion rate of cyclohexene, large process circulation and high energy consumption in cyclohexene hydration catalysis, the present invention provides a ZSM-5 molecular sieve catalyst and its preparation method and application, prepared by using alkaline ionic liquid as template Molecular sieve catalyst. In alkaline environment, the structural crystal form of molecular sieve grows more fully, and the prepared ZSM-5 catalyst has higher reactivity.

In order to achieve the above object, the present invention adopts the following technical solutions:

A ZSM-5 molecular sieve is prepared by hydrothermal synthesis using an alkaline ionic liquid as a template, and the alkaline ionic liquid template is an imidazole ionic liquid and a tetrabutylammonium ionic liquid.

Specifically, the alkaline ionic liquid can be selected from 1-ethyl-3-methylimidazole hydrochloride, 1-ethyl-3-methylimidazole acetate, 1-ethyl-3-methylimidazole Hexafluorophosphate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, methoxyl 1-ethyl-3-methylimidazolium and One or more of tetrabutylammonium acetate.

In one embodiment of the present invention, the silicon-aluminum ratio in the ZSM-5 molecular sieve catalyst is 20-100, preferably 28-80. Exemplarily, the silicon-aluminum ratio is 28, 30, 35, 40, 60, 80 or any value within the range between any two values mentioned above.

In one embodiment of the present invention, the ZSM-5 molecular sieve has a specific surface area of 300-900 m ² /g, a particle size of 0.1-5 μm, and a pore size of 2-5 nm.

Preferably, the ZSM-5 molecular sieve has a specific surface area of 400-800 m ² /g, a particle size of 1-3 μm, and a pore size of 2.5-4 nm.

Further preferably, the ZSM-5 molecular sieve has a specific surface area of 420-800 m ² /g, a particle size of 1-2 μm, and a pore size of 2.9-3.2 nm.

The present invention also provides a preparation method of the above-mentioned ZSM-5 molecular sieve, comprising: performing a hydrothermal reaction with an alkaline ionic liquid, a silicon source, an aluminum source, an alkali source, a dispersant, and water to obtain a ZSM-5 molecular sieve.

In one embodiment of the present invention, the preparation process of described ZSM-5 molecular sieve catalyst comprises:

S1, using 1,3,-dialkylimidazolium bromide or tetrabutyl quaternary ammonium salt as cations, combined with anions to prepare alkaline ionic liquids; the alkaline ionic liquids are capable of accepting protons or donating electron pairs ionic liquid;

S2, adding the above-mentioned basic ionic liquid, silicon source, aluminum source, alkali source, dispersant and water into a container for stirring, then transferring to a hydrothermal kettle, and crystallizing at a certain temperature to obtain a ZSM-5 molecular sieve.

Preferably, it also includes the steps of solid-liquid separation, washing, ion exchange, drying and roasting of the reaction system after the reaction. The solid-liquid separation can be done by conventional means in the art, such as filtration, centrifugation and the like.

Preferably, the anions in the step S1 include one or more of acetate, hexafluorophosphate and tetrafluoroborate.

In one embodiment of the present invention, 1,3,-dialkyl imidazolium bromide or quaternary ammonium salt cations and anions are added to the solvent and mixed, stirred at room temperature, filtered to remove the precipitate, and the filtrate is rotary evaporated to remove the solvent to prepare the base Sexual ionic liquids.

In one embodiment of the present invention, the molar ratio of the water to the silicon source is 0.8-50:1; the molar ratio of the silicon source to the aluminum source is 20-200:1, and the molar ratio of the alkali source to the silicon source The ratio is 0.05-2:1, the molar ratio of the basic ionic liquid template agent to the silicon source is 0.05-2:1, and the molar ratio of the dispersant to the silicon source is 0.01-2:1.

Preferably, the molar ratio of the silicon source to the aluminum source is 20-100:1.

For example, the molar ratio of the silicon source to the aluminum source is 20, 28, 30, 35, 40, 60, 80, 100 or any value within the range between any two values mentioned above.

In one embodiment of the present invention, the silicon source is one or more of sodium silicate, silica sol, tetraethyl orthosilicate, water glass and chromatographic silica gel.

Preferably, the aluminum source is one or more of aluminum sulfate, sodium metaaluminate, aluminum isopropoxide and boehmite.

Preferably, the alkali source is one or more of sodium hydroxide, potassium hydroxide, barium hydroxide and sodium carbonate.

Preferably, the dispersant is a water-soluble surfactant, more preferably one or more of sodium lauryl sulfate, sodium dodecylbenzenesulfonate and polyethylene glycol 400.

In one embodiment of the present invention, the crystallization temperature is 100-180° C., and the crystallization time is 12-72 hours.

Specifically, in the hydrothermal crystallization step, the solution may be transferred to a hydrothermal kettle, and then placed in a rotary oven at a rotational speed of 5-100 rpm.

In one embodiment of the present invention, the method for preparing the basic ionic liquid template in the step S1 includes:

Tetrabutylammonium bromide and potassium acetate are added to a container containing methanol in a molar ratio of 1:1-2, stirred and reacted at room temperature for 3-24 hours, filtered to remove the precipitate, and a filtrate is obtained;

Rotate the filtrate to remove methanol, then add ether to wash, so that unreacted potassium acetate precipitates out, filter, and rotate the filtrate at 30-55 ° C to obtain a colorless liquid tetrabutyl acetate [TBA][ Ac].

Preferably, the molar ratio of tetrabutylammonium bromide to potassium acetate is 1:1.2.

The present invention also provides a ZSM-5 molecular sieve prepared by the above method.

The present invention also provides the application of the above-mentioned ZSM-5 molecular sieve as a catalyst, for example, the application in catalyzing the preparation of cyclohexanol from cyclohexene. Preference is given to the use in the preparation of cyclohexanol by hydration of cyclohexene.

The present invention also provides a method for preparing cyclohexanol, which comprises mixing the above-mentioned ZSM-5 molecular sieve catalyst, cyclohexene and water, and performing a hydration reaction to prepare cyclohexanol.

In one embodiment of the present invention, the molar ratio of the water and cyclohexene is (0.5-10):1, preferably (1-8):1, for example, 8:1, 6.8:1, 5:1 , 4:1, 3.5:1, 3:1, 2.5:1, 2:1, 1.5:1, 1:1.

In one embodiment of the present invention, the mass ratio of the ZSM-5 molecular sieve catalyst to cyclohexene is (0.1-2.0):1; for example, 0.1:1, 0.2:1, 0.4:1, 0.6:1, 0.8 :1, 1.0:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1, 2.0:1.

In one embodiment of the present invention, the temperature of the hydration reaction is 100-140°C. For example, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C.

In one embodiment of the present invention, the pressure of the hydration reaction is 0.1-1Mpa, for example, 0.1MPa, 0.2MPa, 0.3MPa, 0.4MPa, 0.5MPa, 0.6MPa, 0.7MPa, 0.8MPa, 0.9MPa, 1.0MPa.

In one embodiment of the present invention, the time for the hydration reaction is 0.5-3h, for example, 0.5h, 1h, 2h, 2.5h, 3h.

Beneficial effects of the present invention

1. The present invention uses basic ionic liquids as templates to prepare ZSM-5 molecular sieve catalysts. Basic ionic liquids are used as structure-directing agents. In alkaline environments, there are π-π stacking or hydrogen bond interactions between the molecules of basic ionic liquids. Equally easy to self-assemble into a regular shape, the structural crystal growth of the molecular sieve is more sufficient, and the molecular sieve is induced to form a form with high crystallinity, small crystal grains, uniform particle size, and large specific surface area, so a highly efficient and highly active hydrogen ZSM- 5 molecular sieves, higher reactivity and better conversion rate of cyclohexene.

2. The preparation process of the catalyst is simple, the acid site of the catalyst can be adjusted, and the prepared product has good hydrothermal stability, high activity, and good effect. It is applied in the catalytic reaction of cyclohexene with high conversion rate and good selectivity of cyclohexanol , and the raw materials used are safe, environmentally friendly and low in cost, and can be used in industrial production.

3, the present invention adopts alkaline ionic liquid as the ZSM-5 molecular sieve catalyst prepared by template agent, has higher specific surface area and active site, can significantly improve the conversion rate of cyclohexene and the yield of cyclohexanol, the High-efficiency and high-activity ZSM-5 molecular sieve was used as a catalyst for the first time in the system of cyclohexene hydration reaction to prepare cyclohexanol, which increased the conversion rate of cyclohexene by more than 2 times, and the selectivity of cyclohexanol remained at 99.5%. Above, the conversion rate of cyclohexene and the yield of cyclohexanol are significantly improved, and under the condition of unchanged production process, the production capacity of cyclohexanol is increased by about 2 times, and the prospect of being applied to large-scale industrial production is broad , with obvious economic, social and environmental benefits. At the same time, it solves the problem of high energy consumption due to the low conversion rate of cyclohexene, which requires multiple cycles of separation and re-reaction of cyclohexene, and the energy consumption of the process is reduced by more than 30%. The economic benefits are considerable, and it can be widely used in the industrial production of cyclohexanol .

Description of drawings

Figure 1 is a gas chromatogram of cyclohexanol prepared in Example 1 of the present invention.

Fig. 2 is an XRD pattern of the ZSM-5 molecular sieve catalyst prepared in Example 1 of the present invention.

3 is a gas chromatogram of cyclohexanol prepared in Comparative Example 1.

Detailed ways

The technical solutions of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following examples are only for illustrating and explaining the present invention, and should not be construed as limiting the protection scope of the present invention. All technologies realized based on the above contents of the present invention are covered within the scope of protection intended by the present invention.

Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

Example 1

[Preparation of molecular sieve catalyst]

Add tetrabutylammonium bromide and potassium acetate into a round-bottomed flask containing methanol at a molar ratio of 1:1.2, stir and react at room temperature for 12 hours, filter to remove the precipitate, remove methanol from the filtrate by rotary evaporation, add diethyl ether to wash, and the precipitate is separated out. The reacted potassium acetate was filtered, and the filtrate was evaporated under reduced pressure at 30° C. to remove ether to obtain a basic ionic liquid tetrabutylammonium acetate.

Add 178g of silica sol (mass concentration 30%), 13.32g of aluminum sulfate, 5.4g of sodium hydroxide, 30g of tetrabutylammonium acetate of alkaline ionic liquid, 16g of sodium dodecylbenzenesulfonate and 500g of water into a three-necked flask in sequence , after stirring at room temperature for 2 h, the solution was transferred to a hydrothermal kettle, placed in a rotary oven (speed: 10 rpm), and crystallized at 170° C. for 24 h. After natural cooling to room temperature, the solid product was centrifuged, washed with high-purity water, ion-exchanged with 0.5 mol/L dilute sulfuric acid at 60°C for 4 hours, and calcined at 550°C for 5 hours to obtain the catalyst ZSM-5.

The silicon-aluminum ratio of the catalyst ZSM-5 is 28, the specific surface area is 462m ² /g, and the particle size is 1-2μm. After 6 decay experiments, the catalyst activity was 98%.

[Application of catalyst to cyclohexene hydration reaction]

Put 50g of the ZSM-5 catalyst prepared above, 50g of cyclohexene and 75g of water into the autoclave and apply a nitrogen pressure of 0.5MPa under stirring to replace the gas three times, heat to 125°C, and adjust the reaction pressure to 0.5 MPa, stop heating after 2 hours of reaction, cool naturally to room temperature, cool to 20°C with ice water, and separate the organic phase and the water phase. The organic phase was taken for gas chromatographic analysis, and the conversion rate of cyclohexene and the selectivity of cyclohexanol were calculated.

Fig. 1 is the gas chromatogram of the cyclohexanol that embodiment 1 prepares. In the figure, the peak area with a retention time of 2.191 min is 708591167; the peak area with a retention time of 2.825 min is 3379437; the peak area with a retention time of 9.031 min is 224846226; the peak area with a retention time of 16.905 min is 850280. The ratio of the sum of peak areas (229075943) with retention times of 2.825, 9.031 and 16.905 min to the total peak area (937667110) is the conversion rate of cyclohexene 24.43%;

The ratio of the peak area (224846226) with a retention time of 9.031 min to the total peak area (224846226+850280=225696506) is the selectivity of cyclohexanol of 99.62%.

Fig. 2 is the XRD figure of catalyst ZSM-5 in the embodiment 1, shows in the figure, 2θ=7.80 °, 8.80 °, 23.20 °, 23.80 ° and 24.30 ° etc. all show the sharp characteristic diffraction peak of typical MFI crystal structure, It shows that it is ZSM-5 molecular sieve with good crystallization.

Example 2

[Preparation of catalyst]

Add 1-ethyl-3-methylimidazole hydrochloride and potassium hexafluorophosphate in a molar ratio of 1:1.1 into a round-bottomed flask containing acetone, stir and react at room temperature for 18 hours, filter to remove the precipitate, and rotate the filtrate under reduced pressure Acetone was removed by evaporation, ether was added to wash, filtered, and the filtrate was evaporated under reduced pressure at 30°C to remove the solvent to obtain 1-ethyl-3-methylimidazolium hexafluorophosphate in a colorless liquid state.

Silica sol (mass concentration 30%) 200.28g, aluminum sulfate 10.26g, sodium hydroxide 6.0g, 1-ethyl-3-methylimidazolium hexafluorophosphate 25.61g, sodium dodecylbenzenesulfonate 17.42g Add water and 500g to a three-necked flask in turn, and after stirring for 2 hours, transfer the solution to a hydrothermal kettle, place it in a rotary oven (speed: 10 rpm), and crystallize at 170°C for 24 hours. After natural cooling to room temperature, the solid product was centrifuged, washed with high-purity water, ion-exchanged with 0.5 mol/L dilute sulfuric acid at 60°C for 4 hours, and calcined at 550°C for 5 hours to obtain the catalyst ZSM-5.

The silicon-aluminum ratio of the catalyst ZSM-5 is 35, the specific surface area is 456m ² /g, and the particle size is 1-2μm. After 6 decay experiments, the catalyst activity was 98%.

[Application of catalyst to cyclohexene hydration reaction]

Put 50g of ZSM-5 catalyst, 50g of cyclohexene and 75g of water into the autoclave and apply a nitrogen pressure of 0.5MPa under stirring to replace the gas three times, heat to 125°C, adjust the reaction pressure to 0.5MPa, and wait After 2 hours of reaction, the heating was stopped, cooled to room temperature naturally, cooled to 20° C. with ice water, and the organic phase was separated from the water phase.

The organic phase was taken for gas chromatographic analysis, and the conversion rate of cyclohexene and the selectivity of cyclohexanol were calculated.

Example 3

[Preparation of catalyst]

Add 1-ethyl-3-methylimidazole hydrochloride and potassium acetate solution in a molar ratio of 1:1.2 to a round-bottomed flask containing acetone, stir and react at room temperature for 12 hours, filter to remove the precipitate, add ether to wash and filter, and The filtrate was evaporated under reduced pressure at 30°C to remove the solvent to obtain 1-ethyl-3-methylimidazole acetate in a colorless liquid state.

Add 122g of sodium silicate, 3.3g of sodium metaaluminate, 8.42g of potassium hydroxide, 17.02g of 1-ethyl-3-methylimidazole acetate, 17.42g of sodium dodecylbenzenesulfonate and 500g of water in sequence After stirring the three-neck flask for 2 hours, the solution was transferred to a hydrothermal kettle, placed in a rotary oven (speed: 10 rpm), and crystallized at 170° C. for 24 hours. After natural cooling to room temperature, the solid product was centrifuged, washed with high-purity water, ion-exchanged with 0.5 mol/L dilute sulfuric acid at 60°C for 4 hours, and calcined at 550°C for 5 hours to obtain the catalyst ZSM-5.

The silicon-aluminum ratio of the catalyst ZSM-5 is 52, the specific surface area is 470m ² /g, and the particle size is 1-2μm. After 6 decay experiments, the catalyst activity was 98.1%.

[Application of catalyst to cyclohexene hydration reaction]

Put 50g of ZSM-5 catalyst, 50g of cyclohexene and 75g of water into the autoclave and apply a nitrogen pressure of 0.5MPa under stirring to replace the gas three times, heat to 125°C, adjust the reaction pressure to 0.5MPa, and wait After 2 hours of reaction, the heating was stopped, cooled to room temperature naturally, cooled to 20° C. with ice water, and the organic phase was separated from the water phase.

The organic phase was taken for gas chromatographic analysis, and the conversion rate of cyclohexene and the selectivity of cyclohexanol were calculated.

Example 4

[Preparation of catalyst]

Add 1-butyl-3-methylimidazole hydrochloride and potassium hexafluorophosphate in a molar ratio of 1:1.1 into a round-bottomed flask containing acetone, stir and react at room temperature for 18 hours, filter to remove the precipitate, and rotate the filtrate under reduced pressure The acetone was removed by evaporation, ether was added to wash, filtered, and the filtrate was evaporated under reduced pressure at 30°C to remove the solvent to obtain a colorless liquid 1-butyl-3-methylimidazolium hexafluorophosphate.

Add 60.08 g of chromatographic silica gel, 3.06 g of boehmite, 6.0 g of sodium hydroxide, 28.41 g of 1-butyl-3-methylimidazole acetate, 20 g of polyethylene glycol 400 and 500 g of water into a three-necked flask in sequence, After stirring for 2 hours, the solution was transferred to a hydrothermal kettle, placed in a rotary oven (speed: 10 rpm), and crystallized at 160° C. for 36 hours. After natural cooling to room temperature, the solid product was centrifuged, washed with high-purity water, ion-exchanged with 0.5 mol/L dilute sulfuric acid at 60°C for 4 hours, and calcined at 550°C for 5 hours to obtain the catalyst ZSM-5.

The silicon-aluminum ratio of the catalyst ZSM-5 is 35, the specific surface area is 450m ² /g, and the particle size is 1-2μm. After 6 decay experiments, the catalyst activity was 97.8%.

[Application of catalyst to cyclohexene hydration reaction]

Put 50g of ZSM-5 catalyst, 50g of cyclohexene and 75g of water into the autoclave and apply a nitrogen pressure of 0.5MPa under stirring to replace the gas three times, heat to 125°C, adjust the reaction pressure to 0.5MPa, and wait After 2 hours of reaction, the heating was stopped, cooled to room temperature naturally, cooled to 20° C. with ice water, and the organic phase was separated from the water phase.

The organic phase was taken for gas chromatographic analysis, and the conversion rate of cyclohexene and the selectivity of cyclohexanol were calculated.

Example 5

[Preparation of catalyst]

Add 1-ethyl-3-methylimidazole bromide and sodium methoxide in a molar ratio of 1:1.1 to a round-bottomed flask containing absolute ethanol, stir and react at room temperature for 16 hours, filter to remove the white solid, and spin the filtrate under reduced pressure Ethanol was removed by evaporation to give methoxylated 1-ethyl-3-methylimidazolium salt as a colorless liquid.

264.26g of tetraethyl orthosilicate, 4.08g of aluminum isopropoxide, 6.0g of sodium hydroxide, 14.22g of 1-ethyl-3-methylimidazolium methoxide, 17.42g of sodium dodecylbenzenesulfonate and 500 g of water was added to the three-necked flask in turn, and after stirring for 2 hours, the solution was transferred to a hydrothermal kettle, placed in a rotary oven (speed: 10 rpm), and crystallized at 170°C for 24 hours. After natural cooling to room temperature, the solid product was centrifuged, washed with high-purity water, ion-exchanged with 0.5 mol/L dilute sulfuric acid at 60°C for 4 hours, and calcined at 550°C for 5 hours to obtain the catalyst ZSM-5.

The silicon-aluminum ratio of the catalyst ZSM-5 is 80, the specific surface area is 460m ² /g, and the particle size is 1-2μm. After 6 decay experiments, the catalyst activity was 98.2%.

[Application of catalyst to cyclohexene water and reaction]

Put 50g of ZSM-5 catalyst, 50g of cyclohexene and 75g of water into the autoclave and apply a nitrogen pressure of 0.5MPa under stirring to replace the gas three times, heat to 125°C, adjust the reaction pressure to 0.5MPa, and wait After 2 hours of reaction, the heating was stopped, cooled to room temperature naturally, cooled to 20° C. with ice water, and the organic phase was separated from the water phase.

The organic phase was taken for gas chromatographic analysis, and the conversion rate of cyclohexene and the selectivity of cyclohexanol were calculated.

Comparative example 1

A ZSM-5 molecular sieve catalyst and a method for catalyzing cyclohexene to synthesize cyclohexanol, the steps are as follows:

Take commercially available ZSM-5 molecular sieve (purchased from Shandong Yutai Chemical Co., Ltd., using hexamethylenediamine as template) 50g (silicon-aluminum ratio is 28, specific surface area is ^410m2 /g, particle size is 1-2μm) and added to 500mL In the autoclave, add 50g of cyclohexene and 75g of high-purity water, apply 0.5MPa nitrogen pressure under stirring to replace the gas in the reactor three times, heat to 125°C, adjust the reaction pressure to 0.5MPa, and wait for the reaction to proceed Stop heating after 2h, cool to room temperature naturally, cool to 20°C with ice water, and separate the organic phase and the water phase.

The organic phase was taken for gas chromatographic analysis, and the conversion rate of cyclohexene and the selectivity of cyclohexanol were calculated.

3 is a gas chromatogram of cyclohexanol prepared in Comparative Example 1. In the figure, the peak area with a retention time of 2.194min is 771126774; the peak area with a retention time of 2.830min is 2976244; the peak area with a retention time of 7.054min is 1032739; the peak area with a retention time of 8.839min is 93559969; The peak area at 10.544min was 386102. Retention time is 2.830,7.054,8.839,10.544min peak area sum (97955054) accounts for the ratio of whole peak area (869081828) and is the conversion rate of cyclohexene 11.27%; Retention time is 8.839min peak area (93559969 ) to the total peak area (1032739+93559969+386102=94978810) is the selectivity of cyclohexanol 98.51%.

The results of cyclohexene conversion and cyclohexanol selectivity in Examples 1-5 and Comparative Example 1 are shown in Table 1 below.

Table 1 The reaction result of cyclohexene hydration catalysis to prepare cyclohexanol

Cyclohexene conversion (%) Cyclohexanol selectivity (%) Example 1 24.43 99.62 Example 2 24.56 99.69 Example 3 23.85 99.72 Example 4 23.92 99.78 Example 5 24.29 99.81 Comparative example 1 11.27 98.51

As can be seen from the above table 1, the present invention adopts alkaline ionic liquid as a template to prepare the cyclohexene conversion rate of the ZSM-5 molecular sieve catalyst in the reaction much higher than that of the catalyst adopted in Comparative Example 1, indicating that the present invention prepares The catalyst is a highly efficient and highly active hydrogen-type ZSM-5 molecular sieve with higher reactivity and better conversion rate of cyclohexene.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above-mentioned embodiments. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. A ZSM-5 molecular sieve catalyst, is characterized in that, adopts basic ionic liquid as template and prepares by hydrothermal synthesis, and described basic ionic liquid template is imidazoles ionic liquid and tetrabutylammonium ion liquid. 2. ZSM-5 molecular sieve catalyst according to claim 1, is characterized in that, described alkaline ionic liquid is selected from 1-ethyl-3-methylimidazole hydrochloride, 1-ethyl-3-methyl Imidazole acetate, 1-ethyl-3-methylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate , one or more of methoxylated 1-ethyl-3-methylimidazolium salt and tetrabutylammonium acetate. 3. The ZSM-5 molecular sieve catalyst according to claim 1, characterized in that the silicon-aluminum ratio in the ZSM-5 molecular sieve catalyst is 20-100; preferably 28-80. For example, the silicon-aluminum ratio is 28, 30, 35, 40, 60, 80 or any value within the range between any two values mentioned above. Preferably, the ZSM-5 molecular sieve catalyst has a specific surface area of 300-900 m ² /g, a particle size of 0.1-5 μm, and a pore size of 2-5 nm. Further preferably, the ZSM-5 molecular sieve catalyst has a specific surface area of 400-800 m ² /g, a particle size of 1-3 μm, and a pore size of 2.5-4 nm. More preferably, the ZSM-5 molecular sieve catalyst has a specific surface area of 420-800 m ² /g, a particle size of 1-2 μm, and a pore size of 2.9-3.2 nm. 4. a method for preparing ZSM-5 molecular sieve catalyst, is characterized in that, comprises preparation basic ionic liquid template, with described basic ionic liquid template and reaction raw material silicon source, aluminum source, alkali source and dispersant, Water is subjected to hydrothermal crystallization to obtain a ZSM-5 molecular sieve catalyst. 5. method according to claim 4, is characterized in that, the preparation process of described ZSM-5 molecular sieve catalyst comprises: S1, using 1,3-dialkyl imidazolium bromide or quaternary ammonium salt as a cation, combined with an anion to prepare an alkaline ionic liquid template; S2, adding the above-mentioned alkaline ionic liquid template agent and reaction raw materials silicon source, aluminum source, alkali source, dispersant, and water into a container to form a reaction system, after stirring, transfer to a hydrothermal kettle, and crystallize at a certain temperature, A ZSM-5 molecular sieve catalyst is obtained. Preferably, it also includes the steps of solid-liquid separation, washing, ion exchange, drying and roasting of the reaction system after the reaction. Preferably, the anions in the step S1 include one or more of acetate, hexafluorophosphate and tetrafluoroborate. Preferably, 1,3-dialkylimidazolium bromide or quaternary ammonium salt cations and anions are added to the solvent and mixed, stirred at room temperature, filtered to remove the precipitate, and the filtrate is rotatably evaporated to remove the solvent to prepare an alkaline ionic liquid template. 6. The method according to claim 1, characterized in that, the mol ratio of the water to the silicon source is 0.8-50:1; the mol ratio of the silicon source to the aluminum source is 20-200:1, and the The molar ratio of the alkali source to the silicon source is 0.05-2:1, the molar ratio of the alkaline ionic liquid template to the silicon source is 0.05-2:1, and the molar ratio of the dispersant to the silicon source is 0.01-2 :1. Preferably, the molar ratio of the silicon source to the aluminum source is 20-100:1. For example, the molar ratio of the silicon source to the aluminum source is 20, 28, 30, 35, 40, 60, 80, 100 or any value within the range between any two values mentioned above. 7. The method according to claim 1, wherein the silicon source is one or more of sodium silicate, silica sol, tetraethyl orthosilicate, water glass and chromatographic silica gel. Preferably, the aluminum source is one or more of aluminum sulfate, sodium metaaluminate, aluminum isopropoxide and boehmite. Preferably, the alkali source is one or more of sodium hydroxide, potassium hydroxide, barium hydroxide and sodium carbonate. Preferably, the dispersant is a water-soluble surfactant. Further preferably, the dispersant is selected from one or more of sodium lauryl sulfate, sodium dodecylbenzenesulfonate and polyethylene glycol 400. 8. The method according to claim 1, characterized in that, the crystallization temperature is 100-180° C., and the crystallization time is 12-72 hours. Preferably, in the hydrothermal crystallization step, after the solution is transferred to a hydrothermal kettle, it is placed in a rotary oven at a rotational speed of 5-100 rpm. 9. The method according to claim 1, wherein the step S1 comprises: Tetrabutylammonium bromide and potassium acetate are added to a container containing methanol in a molar ratio of 1:1-2, stirred and reacted at room temperature for 3-24 hours, filtered to remove the precipitate, and a filtrate is obtained; Rotate the filtrate to remove methanol, then add ether to wash, so that unreacted potassium acetate precipitates out, filter, and rotate the filtrate at 30-55 ° C to obtain a colorless liquid tetrabutyl acetate [TBA][ Ac]. Preferably, the molar ratio of tetrabutylammonium bromide to potassium acetate is 1:1.2. 10. the catalyst that the ZSM-5 molecular sieve catalyst described in any one in claim 1 to 3 and/or the ZSM-5 molecular sieve catalyst preparation method in claim 4-9 obtains prepares cyclohexene in catalytic cyclohexene Alcohol application. Preferably, the application of the ZSM-5 molecular sieve catalyst in the preparation of cyclohexanol by mixing cyclohexene and water for hydration reaction, Wherein, the molar ratio of the water and cyclohexene is (0.5-10):1, preferably (1-8):1, for example, 8:1, 6.8:1, 5:1, 4:1, 3.5 :1, 3:1, 2.5:1, 2:1, 1.5:1, 1:1. The mass ratio of the ZSM-5 molecular sieve catalyst to cyclohexene is (0.1-2.0):1; for example, 0.1:1, 0.2:1, 0.4:1, 0.6:1, 0.8:1, 1.0:1, 1.2 :1, 1.4:1, 1.6:1, 1.8:1, 2.0:1. Preferably, the temperature of the hydration reaction is 100-140°C. For example, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C. Preferably, the pressure of the hydration reaction is 0.1-1Mpa, for example, 0.1MPa, 0.2MPa, 0.3MPa, 0.4MPa, 0.5MPa, 0.6MPa, 0.7MPa, 0.8MPa, 0.9MPa, 1.0MPa. Preferably, the hydration reaction time is 0.5-3h, for example, 0.5h, 0.8h, 1.0h, 1.2h, 1.4h, 1.6h, 1.8h, 2h, 2.2h, 2.4h, 2.5h, 2.6h, 2.8h h, 3h.

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