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

Abstract

The present invention provides a kind of ZSM 5 molecular sieve catalyst and its preparation method and application, ZSM 5 molecular sieve catalyst uses basic ionic liquid as template and is prepared by hydrothermal crystallization method, wherein, basic ionic liquid template is imidazole ionic liquid and tetrabutylammonium ionic liquid, ionic liquid is with bromide 1,3 dialkyl imidazole salt or quaternary ammonium salt as cation, prepared in conjunction with different anions, with silicon source, aluminum source, alkali source and water as raw material, through the preparation of template, the preparation of reaction mixture and hydrothermal crystallization three steps, then through solid-liquid separation, washing, ion exchange, drying and roasting, obtain hydrogen type ZSM 5 molecular sieve.The preparation process is simple, catalyst acid site is adjustable, and products obtained therefrom hydrothermal stability is good, activity is high, effect is good, so that the conversion rate of cyclohexene is high, cyclohexanol selectivity is good, and raw materials used are safe, process is simple, can be used for industrial production.

Description

Technical Field

[0001] The present invention belongs to the technical field of molecular sieve catalyst preparation, and specifically relates to a ZSM-5 molecular sieve catalyst and a preparation method and application thereof, and more particularly to a method for preparing a ZSM-5 molecular sieve using an alkaline ionic liquid as a template and application thereof. Background Art

[0002] Cyclohexanol is an important chemical intermediate, primarily used as an intermediate raw material in the production of products such as adipic acid, caprolactam, and nylon. Currently, there are three methods for producing cyclohexanol: cyclohexane oxidation, phenol hydrogenation, and direct cyclohexene hydration. Four main types of catalysts are used in direct cyclohexene hydration: inorganic acids and their salts, acidic oxides, heteropolyacids, and ion exchange resins. Inorganic acid catalysts, such as sulfuric acid, were used earlier. However, this process is energy-intensive, product separation is difficult, and equipment corrosion by sulfuric acid is a risk. Ion exchange resins are widely used in the hydration reaction to produce cyclohexanol due to their strong acidity. Different ion exchange resins provide varying types and strengths of acidic sites, which influence the reaction in different ways. Lin Qingxiang et al. from Zhejiang University investigated the catalytic performance of seven different ion exchange resins. The results showed that the strongly acidic cation exchange resins Amberlyst 36wet, Amberlyst 35wet, and ZGC107 exhibited the highest catalytic activity. Although ion exchange resins solve problems such as product recovery compared to inorganic acid catalysts, their inherent shortcomings of poor thermal stability, easy deactivation, and short life limit their further industrial application.

[0003] In the 1980s, Asahi Kasei Corporation of Japan developed Ru and HZSM-5 catalysts and used them in the hydrogenation of phenol to cyclohexene and the hydration of cyclohexene to cyclohexanol. In 1983, they applied for a patent for a cyclohexene hydration process catalyzed by solid acid molecular sieves. Zeolite molecular sieves have been a research focus for olefin hydration catalysts in recent years due to their suitable acidity, high mechanical strength, and excellent thermal stability. Studies have shown that factors such as the crystal size, acidity, and crystallinity of the molecular sieve significantly influence its structure and performance. Zhang et al. studied the cyclohexene hydration process catalyzed by zeolites. Their results showed that a SiO2 / Al2O3 ratio of 30-50 for the ZSM-5 zeolite molecule achieved a cyclohexanol selectivity of 99%, indicating optimal catalytic activity. However, cyclohexene hydration to cyclohexanol is limited by chemical equilibrium, resulting in low cyclohexene conversion per pass (7-10%), and the process suffers from high recycle volumes and energy consumption.

[0004] Therefore, it is necessary to seek a new type of catalyst to break the chemical balance of the traditional process and improve the conversion rate of cyclohexene hydration to prepare cyclohexanol. Summary of the Invention

[0005] To address the problems of low cyclohexene conversion, large process cycles, and high energy consumption in cyclohexene hydration catalysis, the present invention provides a ZSM-5 molecular sieve catalyst, its preparation method, and application. The molecular sieve catalyst is prepared using an alkaline ionic liquid as a template. In an alkaline environment, the molecular sieve's structural crystals grow more fully, resulting in a ZSM-5 catalyst with higher reactivity.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A ZSM-5 molecular sieve is prepared by hydrothermal synthesis using an alkaline ionic liquid as a template, wherein the alkaline ionic liquid template is an imidazole ionic liquid and a tetrabutylammonium ionic liquid.

[0008] Specifically, the alkaline ionic liquid can be selected from one or more of 1-ethyl-3-methylimidazolium hydrochloride, 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium methoxide and tetrabutylammonium acetate.

[0009] In one embodiment of the present invention, the silicon-to-aluminum ratio of the ZSM-5 molecular sieve catalyst is 20-100, preferably 28-80. For example, the silicon-to-aluminum ratio is 28, 30, 35, 40, 60, 80 or any point in the range between any two of the aforementioned values.

[0010] In one embodiment of the present invention, the specific surface area of ​​the ZSM-5 molecular sieve is 300-900m 2 / g, particle size is 0.1-5μm, and pore size is 2-5nm.

[0011] Preferably, the specific surface area of ​​the ZSM-5 molecular sieve is 400-800m 2 / g, particle size is 1-3μm, and pore size is 2.5-4nm.

[0012] Further preferably, the specific surface area of ​​the ZSM-5 molecular sieve is 420-800m 2 / g, particle size is 1-2μm, and pore size is 2.9-3.2nm.

[0013] The present invention also provides a method for preparing the ZSM-5 molecular sieve, comprising subjecting an alkaline ionic liquid to a hydrothermal reaction with a silicon source, an aluminum source, an alkali source, a dispersant, and water to obtain the ZSM-5 molecular sieve.

[0014] In one embodiment of the present invention, the preparation process of the ZSM-5 molecular sieve catalyst includes:

[0015] S1, using 1,3-dialkylimidazolium bromide or tetrabutyl quaternary ammonium salt as a cation and combining it with an anion to prepare an alkaline ionic liquid; the alkaline ionic liquid refers to an ionic liquid that can accept protons or donate electron pairs;

[0016] S2, adding the alkaline ionic liquid, silicon source, aluminum source, alkali source, dispersant and water into a container and stirring, then transferring the mixture into a hydrothermal kettle and crystallizing at a certain temperature to obtain ZSM-5 molecular sieve.

[0017] Preferably, the process further comprises the steps of solid-liquid separation, washing, ion exchange, and drying and calcining the reaction system after the reaction is completed. The solid-liquid separation can be carried out by conventional means in the art, such as filtration, centrifugation, etc.

[0018] Preferably, the anion in step S1 includes one or more of acetate, hexafluorophosphate and tetrafluoroborate.

[0019] In one embodiment of the present invention, 1,3-dialkylimidazolium bromide or quaternary ammonium salt cations and anions are added to a solvent and mixed, stirred at room temperature, filtered to remove the precipitate, and the filtrate is rotary evaporated to remove the solvent to prepare an alkaline ionic liquid.

[0020] In one embodiment of the present invention, the molar ratio of water to silicon source is 0.8-50:1; the molar ratio of silicon source to aluminum source is 20-200:1, the molar ratio of alkali source to silicon source is 0.05-2:1, the molar ratio of alkaline ionic liquid template to silicon source is 0.05-2:1, and the molar ratio of dispersant to silicon source is 0.01-2:1.

[0021] Preferably, the molar ratio of the silicon source to the aluminum source is 20-100:1.

[0022] For example, the molar ratio of the silicon source to the aluminum source is 20, 28, 30, 35, 40, 60, 80, 100 or any point in the range between any two of the aforementioned values.

[0023] In one embodiment of the present invention, the silicon source is one or more of sodium silicate, silica sol, tetraethyl orthosilicate, water glass and chromatography silica gel.

[0024] Preferably, the aluminum source is one or more of aluminum sulfate, sodium metaaluminate, aluminum isopropoxide and boehmite.

[0025] Preferably, the alkali source is one or more of sodium hydroxide, potassium hydroxide, barium hydroxide and sodium carbonate.

[0026] Preferably, the dispersant is a water-soluble surfactant, more preferably one or more of sodium lauryl sulfate, sodium dodecylbenzenesulfonate and polyethylene glycol 400.

[0027] In one embodiment of the present invention, the crystallization temperature is 100-180° C., and the crystallization time is 12-72 hours.

[0028] Specifically, in the hydrothermal crystallization step, the solution can be transferred to a hydrothermal kettle and then placed in a rotary oven at a rotation speed of 5 to 100 rpm.

[0029] In one embodiment of the present invention, the method for preparing the alkaline ionic liquid template in step S1 comprises:

[0030] Tetrabutylammonium bromide and potassium acetate were added to a container containing methanol in a molar ratio of 1:1-2, and the mixture was stirred at room temperature for 3-24 hours. The precipitate was removed by filtration to obtain a filtrate;

[0031] The filtrate was rotary evaporated to remove methanol, and then ether was added for washing to precipitate unreacted potassium acetate. The filtrate was filtered and rotary evaporated at 30-55°C to obtain colorless liquid tetrabutyl acetate [TBA][Ac].

[0032] Preferably, the molar ratio of tetrabutylammonium bromide to potassium acetate is 1:1.2.

[0033] The present invention also provides a ZSM-5 molecular sieve prepared by the method.

[0034] The present invention also provides the use of the ZSM-5 molecular sieve as a catalyst, for example, in catalyzing the production of cyclohexanol from cyclohexene, preferably in the production of cyclohexanol from cyclohexene by hydration.

[0035] The present invention also provides a method for preparing cyclohexanol, comprising mixing the ZSM-5 molecular sieve catalyst, cyclohexene and water, and performing a hydration reaction to prepare cyclohexanol.

[0036] In one embodiment of the present invention, the molar ratio of water to 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.

[0037] 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.

[0038] 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, or 140°C.

[0039] In one embodiment of the present invention, the pressure of the hydration reaction is 0.1-1 MPa, for example, 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa, or 1.0 MPa.

[0040] In one embodiment of the present invention, the hydration reaction time is 0.5 to 3 hours, for example, 0.5 hours, 1 hour, 2 hours, 2.5 hours, or 3 hours.

[0041] Beneficial effects of the present invention

[0042] 1. The present invention uses alkaline ionic liquid as a template to prepare a ZSM-5 molecular sieve catalyst. The alkaline ionic liquid is used as a structure-directing agent. Under an alkaline environment, the alkaline ionic liquid molecules are easily self-assembled into a regular shape due to π-π stacking or hydrogen bonding, and the molecular sieve structure grows more fully, inducing the molecular sieve to form a morphology with high crystallinity, small grains, uniform particle size, and large specific surface area. Therefore, a highly efficient and highly active hydrogen-type ZSM-5 molecular sieve is obtained, which has higher reaction activity and better conversion rate of cyclohexene.

[0043] 2. The catalyst preparation process is simple and the acid sites of the catalyst are adjustable. The product obtained has good hydrothermal stability, high activity and good effect. It is used in the cyclohexene catalytic reaction with high conversion rate and good selectivity for cyclohexanol. The raw materials used are safe, green and environmentally friendly, low cost, and can be used in industrial production.

[0044] 3. The present invention uses a ZSM-5 molecular sieve catalyst prepared using an alkaline ionic liquid as a template. The catalyst has a high specific surface area and active sites, significantly improving the conversion rate of cyclohexene and the yield of cyclohexanol. This efficient and highly active ZSM-5 molecular sieve is used as a catalyst for the first time in a system for preparing cyclohexanol by hydration of cyclohexene, resulting in a more than 2-fold increase in the conversion rate of cyclohexene and a maintenance of a cyclohexanol selectivity of more than 99.5%. Furthermore, while maintaining the same production process, the production capacity of cyclohexanol is increased by approximately 2-fold, showing broad prospects for application in large-scale industrial production and significant economic, social, and environmental benefits. The invention also solves the high energy consumption problem of multiple cycles of cyclohexene separation and subsequent reaction required due to low cyclohexene conversion, reducing process energy consumption by more than 30%, resulting in considerable economic benefits and widespread application in the industrial production of cyclohexanol. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a gas chromatogram of cyclohexanol prepared in Example 1 of the present invention.

[0046] Figure 2 This is the XRD pattern of the ZSM-5 molecular sieve catalyst prepared in Example 1 of the present invention.

[0047] Figure 3 This is the gas chromatogram of cyclohexanol prepared in Comparative Example 1. DETAILED DESCRIPTION

[0048] The technical solutions of the present invention will be described in further detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are encompassed within the scope of protection that the present invention is intended to protect.

[0049] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0050] Example 1

[0051] [Preparation of molecular sieve catalyst]

[0052] Tetrabutylammonium bromide and potassium acetate were added to a round-bottom flask containing methanol in a molar ratio of 1:1.2. The mixture was stirred and reacted at room temperature for 12 hours. The precipitate was removed by filtration. The methanol was removed by rotary evaporation of the filtrate. Ether was added for washing. Unreacted potassium acetate was precipitated and filtered. The filtrate was then rotary evaporated under reduced pressure at 30°C to remove the ether to obtain alkaline ionic liquid tetrabutylammonium acetate.

[0053] 178g of silica sol (30% by mass), 13.32g of aluminum sulfate, 5.4g of sodium hydroxide, 30g of alkaline ionic liquid tetrabutylammonium acetate, 16g of sodium dodecylbenzenesulfonate, and 500g of water were added sequentially to a three-necked flask. After stirring at room temperature for 2 hours, the solution was transferred to a hydrothermal autoclave and placed in a rotary oven (10 rpm) for crystallization at 170°C for 24 hours. After cooling naturally to room temperature, the solid product was centrifuged, washed with high-purity water, ion-exchanged with 0.5mol / L dilute sulfuric acid at 60°C for 4 hours, and calcined at 550°C for 5 hours to obtain the ZSM-5 catalyst.

[0054] The catalyst ZSM-5 has a silicon-aluminum ratio of 28 and a specific surface area of ​​462m 2 / g, with a particle size of 1-2 μm. After 6 decay tests, the catalyst activity was 98%.

[0055] [Application of the catalyst to cyclohexene hydration reaction]

[0056] 50 g of the prepared ZSM-5 catalyst, 50 g of cyclohexene, and 75 g of water were placed in an autoclave and, while stirring, replaced the atmosphere three times with nitrogen at a pressure of 0.5 MPa. The autoclave was heated to 125°C and the reaction pressure was adjusted to 0.5 MPa. After 2 h of reaction, the reaction mixture was stopped from heating and cooled naturally to room temperature. The mixture was then cooled to 20°C with ice water. The organic phase was separated from the aqueous phase. The organic phase was analyzed by gas chromatography to calculate the cyclohexene conversion and cyclohexanol selectivity.

[0057] Figure 1 This is a gas chromatogram of the cyclohexanol prepared in Example 1. In the figure, the peak area at a retention time of 2.191 min is 708,591,167; the peak area at a retention time of 2.825 min is 3,379,437; the peak area at a retention time of 9.031 min is 224,846,226; and the peak area at a retention time of 16.905 min is 850,280. The ratio of the sum of the peak areas at retention times of 2.825, 9.031, and 16.905 min (229,075,943) to the total peak area (937,667,110) represents the cyclohexene conversion rate of 24.43%.

[0058] The ratio of the peak area (224846226) with a retention time of 9.031 min to the total peak area (224846226+850280=225696506) is 99.62% selectivity for cyclohexanol.

[0059] Figure 2 This is the XRD pattern of the catalyst ZSM-5 in Example 1. The figure shows that 2θ = 7.80°, 8.80°, 23.20°, 23.80° and 24.30° all exhibit sharp characteristic diffraction peaks of the typical MFI crystal structure, indicating that it is a well-crystallized ZSM-5 molecular sieve.

[0060] Example 2

[0061] [Preparation of catalyst]

[0062] 1-Ethyl-3-methylimidazole hydrochloride and potassium hexafluorophosphate were added to a round-bottom flask containing acetone in a molar ratio of 1:1.1. The mixture was stirred and reacted at room temperature for 18 h. The precipitate was filtered to remove the acetone. The filtrate was subjected to rotary evaporation under reduced pressure to remove the acetone. Ether was added for washing, the mixture was filtered, and the filtrate was subjected to rotary evaporation under reduced pressure at 30°C to remove the solvent to obtain colorless liquid 1-ethyl-3-methylimidazole hexafluorophosphate.

[0063] 200.28 g of silica sol (30% by mass), 10.26 g of aluminum sulfate, 6.0 g of sodium hydroxide, 25.61 g of 1-ethyl-3-methylimidazolium hexafluorophosphate, 17.42 g of sodium dodecylbenzenesulfonate, and 500 g of water were added sequentially to a three-necked flask. After stirring for 2 hours, the solution was transferred to a hydrothermal autoclave and placed in a rotary oven (speed: 10 rpm) for crystallization at 170°C for 24 hours. After cooling naturally 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 ZSM-5 catalyst.

[0064] The catalyst ZSM-5 has a silicon-aluminum ratio of 35 and a specific surface area of ​​456m 2 / g, with a particle size of 1-2 μm. After 6 decay tests, the catalyst activity was 98%.

[0065] [Application of the catalyst to cyclohexene hydration reaction]

[0066] 50 g of ZSM-5 catalyst, 50 g of cyclohexene and 75 g of water were placed in an autoclave and the gas was replaced three times under a nitrogen pressure of 0.5 MPa under stirring. The reaction was heated to 125 ° C and the reaction pressure was adjusted to 0.5 MPa. After the reaction was allowed to react for 2 h, the heating was stopped, and the mixture was naturally cooled to room temperature. The mixture was cooled to 20 ° C with ice water, and the organic phase was separated from the aqueous phase.

[0067] The organic phase was taken for gas chromatography analysis to calculate the cyclohexene conversion and cyclohexanol selectivity.

[0068] Example 3

[0069] [Preparation of catalyst]

[0070] 1-Ethyl-3-methylimidazole hydrochloride and potassium acetate solution were added to a round-bottom flask containing acetone in a molar ratio of 1:1.2. The mixture was stirred at room temperature for 12 h. The precipitate was removed by filtration. Ether was added for washing and filtration. The filtrate was then subjected to reduced pressure rotary evaporation at 30°C to remove the solvent to obtain colorless liquid 1-ethyl-3-methylimidazole acetate.

[0071] 122g of sodium silicate, 3.3g of sodium metaaluminate, 8.42g of potassium hydroxide, 17.02g of 1-ethyl-3-methylimidazolium acetate, 17.42g of sodium dodecylbenzenesulfonate, and 500g of water were added sequentially to a three-necked flask and stirred for 2 hours. The solution was then transferred to a hydrothermal autoclave and placed in a rotary oven (speed: 10 rpm) for crystallization at 170°C for 24 hours. After cooling naturally to room temperature, the solid product was centrifuged, washed with high-purity water, ion-exchanged with 0.5mol / L dilute sulfuric acid at 60°C for 4 hours, and calcined at 550°C for 5 hours to obtain the ZSM-5 catalyst.

[0072] The catalyst ZSM-5 has a silicon-aluminum ratio of 52 and a specific surface area of ​​470m 2 / g, with a particle size of 1-2 μm. After 6 decay tests, the catalyst activity was 98.1%.

[0073] [Application of the catalyst to cyclohexene hydration reaction]

[0074] 50 g of ZSM-5 catalyst, 50 g of cyclohexene and 75 g of water were placed in an autoclave and the gas was replaced three times under a nitrogen pressure of 0.5 MPa under stirring. The reaction was heated to 125 ° C and the reaction pressure was adjusted to 0.5 MPa. After the reaction was allowed to react for 2 h, the heating was stopped, and the mixture was naturally cooled to room temperature. The mixture was cooled to 20 ° C with ice water, and the organic phase was separated from the aqueous phase.

[0075] The organic phase was taken for gas chromatography analysis to calculate the cyclohexene conversion and cyclohexanol selectivity.

[0076] Example 4

[0077] [Preparation of catalyst]

[0078] 1-Butyl-3-methylimidazole hydrochloride and potassium hexafluorophosphate were added to a round-bottom flask containing acetone in a molar ratio of 1:1.1. The mixture was stirred and reacted at room temperature for 18 h. The precipitate was filtered to remove the acetone. The filtrate was subjected to rotary evaporation under reduced pressure to remove the acetone. Ether was added for washing, the mixture was filtered, and the filtrate was subjected to rotary evaporation under reduced pressure at 30°C to remove the solvent to obtain colorless liquid 1-butyl-3-methylimidazole hexafluorophosphate.

[0079] 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-methylimidazolium acetate, 20 g of polyethylene glycol 400, and 500 g of water were added sequentially to a three-necked flask. After stirring for 2 hours, the solution was transferred to a hydrothermal autoclave and placed in a rotary oven (speed: 10 rpm) for crystallization at 160°C for 36 hours. After cooling naturally 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 ZSM-5 catalyst.

[0080] The catalyst ZSM-5 has a silicon-aluminum ratio of 35 and a specific surface area of ​​450m 2 / g, with a particle size of 1-2 μm. After 6 decay tests, the catalyst activity was 97.8%.

[0081] [Application of the catalyst to cyclohexene hydration reaction]

[0082] 50 g of ZSM-5 catalyst, 50 g of cyclohexene and 75 g of water were placed in an autoclave and the gas was replaced three times under a nitrogen pressure of 0.5 MPa under stirring. The reaction was heated to 125 ° C and the reaction pressure was adjusted to 0.5 MPa. After the reaction was allowed to react for 2 h, the heating was stopped, and the mixture was naturally cooled to room temperature. The mixture was cooled to 20 ° C with ice water, and the organic phase was separated from the aqueous phase.

[0083] The organic phase was taken for gas chromatography analysis to calculate the cyclohexene conversion and cyclohexanol selectivity.

[0084] Example 5

[0085] [Preparation of catalyst]

[0086] 1-Ethyl-3-methylimidazolium bromide and sodium methoxide were added to a round-bottom flask containing anhydrous ethanol in a molar ratio of 1:1.1. The mixture was stirred at room temperature for 16 hours. The white solid was removed by filtration. The filtrate was subjected to reduced pressure rotary evaporation to remove ethanol to obtain a colorless liquid 1-ethyl-3-methylimidazolium methoxide.

[0087]

[0088] 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 500g of water were added sequentially to a three-necked flask and stirred for 2 hours. The solution was then transferred to a hydrothermal autoclave and placed in a rotary oven (speed: 10 rpm) for crystallization at 170°C for 24 hours. After cooling naturally to room temperature, the solid product was centrifuged, washed with high-purity water, ion-exchanged with 0.5mol / L dilute sulfuric acid at 60°C for 4 hours, and calcined at 550°C for 5 hours to obtain the ZSM-5 catalyst.

[0089] The catalyst ZSM-5 has a silicon-aluminum ratio of 80 and a specific surface area of ​​460m 2 / g, with a particle size of 1-2 μm. After 6 decay tests, the catalyst activity was 98.2%.

[0090] [Application of catalyst to cyclohexene-water reaction]

[0091] 50 g of ZSM-5 catalyst, 50 g of cyclohexene and 75 g of water were placed in an autoclave and the gas was replaced three times under a nitrogen pressure of 0.5 MPa under stirring. The reaction was heated to 125 ° C and the reaction pressure was adjusted to 0.5 MPa. After the reaction was allowed to react for 2 h, the heating was stopped, and the mixture was naturally cooled to room temperature. The mixture was cooled to 20 ° C with ice water, and the organic phase was separated from the aqueous phase.

[0092] The organic phase was taken for gas chromatography analysis to calculate the cyclohexene conversion and cyclohexanol selectivity.

[0093] Comparative Example 1

[0094] A ZSM-5 molecular sieve catalyst and a method for catalyzing cyclohexene to synthesize cyclohexanol, comprising the following steps:

[0095] Take 50g of commercially available ZSM-5 molecular sieve (purchased from Shandong Yutai Chemical Co., Ltd., using hexamethylenediamine as template) (silicon-aluminum ratio of 28, specific surface area of ​​410m 2 / g, particle size of 1-2 μm) was added into a 500 mL autoclave, followed by the addition of 50 g of cyclohexene and 75 g of high-purity water. Under stirring, the gas in the reactor was replaced three times under a nitrogen pressure of 0.5 MPa. The mixture was heated to 125° C. and the reaction pressure was adjusted to 0.5 MPa. After the reaction was carried out for 2 h, the heating was stopped, the mixture was naturally cooled to room temperature, cooled with ice water to 20° C., and the organic phase was separated from the aqueous phase.

[0096] The organic phase was taken for gas chromatography analysis to calculate the cyclohexene conversion and cyclohexanol selectivity.

[0097] Figure 3 This is a gas chromatogram of the cyclohexanol prepared in Comparative Example 1. In the figure, the peak area at a retention time of 2.194 min is 771,126,774; the peak area at a retention time of 2.830 min is 2,976,244; the peak area at a retention time of 7.054 min is 1,032,739; the peak area at a retention time of 8.839 min is 93,559,969; and the peak area at a retention time of 10.544 min is 386,102. The ratio of the sum of the peak areas at retention times of 2.830, 7.054, 8.839, and 10.544 min (97,955,054) to the total peak area (869,081,828) is 11.27% for the conversion of cyclohexene; the ratio of the peak area at retention time of 8.839 min (93,559,969) to the total peak area (1,032,739 + 93,559,969 + 386,102 = 94,978,810) is 98.51% for the selectivity of cyclohexanol.

[0098] The cyclohexene conversion and cyclohexanol selectivity results in Examples 1 to 5 and Comparative Example 1 are shown in Table 1 below.

[0099] Table 1 Reaction results of cyclohexene hydration catalysis to prepare cyclohexanol

[0100] Cyclohexene conversion rate (%) 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

[0101] As can be seen from Table 1 above, the cyclohexene conversion rate of the ZSM-5 molecular sieve catalyst prepared by the present invention using alkaline ionic liquid as a template in the reaction is much higher than that of the catalyst used in Comparative Example 1, indicating that the catalyst prepared by the present invention is a highly efficient and highly active hydrogen-type ZSM-5 molecular sieve with higher reaction activity and better cyclohexene conversion rate.

[0102] The above describes the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A ZSM-5 molecular sieve catalyst for catalyzing the production of cyclohexanol from cyclohexene, characterized in that: The ZSM-5 molecular sieve catalyst is prepared by hydrothermal synthesis using an alkaline ionic liquid as a template, wherein the alkaline ionic liquid template is an imidazole ionic liquid; The alkaline ionic liquid is selected from one or more of 1-ethyl-3-methylimidazolium hydrochloride, 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, and 1-ethyl-3-methylimidazolium methoxide; The specific surface area of ​​the ZSM-5 molecular sieve catalyst is 400-800 m 2 / g, particle size is 1-3 μm, and pore size is 2.5-4 nm.

2. Use of the ZSM-5 molecular sieve catalyst according to claim 1 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that: The silicon-aluminum ratio in the ZSM-5 molecular sieve catalyst is 20-100.

3. Use of the ZSM-5 molecular sieve catalyst according to claim 2 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that: The silicon-aluminum ratio in the ZSM-5 molecular sieve catalyst is 28-80.

4. Use of the ZSM-5 molecular sieve catalyst according to claim 3 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that: The silicon-to-aluminum ratio is 28, 30, 35, 40, 60, and 80.

5. The use of the ZSM-5 molecular sieve catalyst according to claim 1 in catalyzing the production of cyclohexanol from cyclohexene, wherein The specific surface area of ​​the ZSM-5 molecular sieve catalyst is 420-800 m 2 / g, particle size is 1-2 μm, and pore size is 2.9-3.2 nm.

6. Use of the ZSM-5 molecular sieve catalyst according to claim 1 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that: The preparation method of the ZSM-5 molecular sieve catalyst comprises preparing an alkaline ionic liquid template, and hydrothermally crystallizing the alkaline ionic liquid template with reaction raw materials of silicon source, aluminum source, alkali source, dispersant and water to obtain the ZSM-5 molecular sieve catalyst.

7. Use of the ZSM-5 molecular sieve catalyst according to claim 6 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that: The preparation process of the ZSM-5 molecular sieve catalyst includes: S1, using 1,3-dialkylimidazolium bromide as a cation and combining it with an anion to prepare a basic ionic liquid template; S2, adding the alkaline ionic liquid template and the reaction raw materials of silicon source, aluminum source, alkali source, dispersant and water into a container to form a reaction system, stirring and transferring the system into a hydrothermal kettle, crystallizing at a certain temperature to obtain a ZSM-5 molecular sieve catalyst.

8. Use of the ZSM-5 molecular sieve catalyst according to claim 7 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that: The preparation process of the ZSM-5 molecular sieve catalyst further includes the steps of solid-liquid separation, washing, ion exchange, and drying and calcining the reaction system after the reaction is completed.

9. Use of the ZSM-5 molecular sieve catalyst according to claim 7 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that: In step S1, the anion includes one or more of acetate, hexafluorophosphate and tetrafluoroborate.

10. Use of the ZSM-5 molecular sieve catalyst according to claim 7 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that: The 1,3-dialkylimidazolium bromide cation and the anion are added to a solvent and mixed, stirred at room temperature, filtered to remove the precipitate, and the filtrate is rotary evaporated to remove the solvent to prepare an alkaline ionic liquid template.

11. Use of the ZSM-5 molecular sieve catalyst according to claim 6 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that: The molar ratio of water to silicon source is 0.8-50:1; the molar ratio of silicon source to aluminum source is 20-200:1; the molar ratio of alkali source to silicon source is 0.05-2:1; the molar ratio of alkaline ionic liquid template to silicon source is 0.05-2:1; and the molar ratio of dispersant to silicon source is 0.01-2:

1.

12. Use of the ZSM-5 molecular sieve catalyst according to claim 11 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that: The molar ratio of the silicon source to the aluminum source is 20-100:

1.

13. Use of the ZSM-5 molecular sieve catalyst according to claim 12 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that: The molar ratio of the silicon source to the aluminum source is 20, 28, 30, 35, 40, 60, 80, or 100.

14. Use of the ZSM-5 molecular sieve catalyst according to claim 6 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that: The silicon source is one or more of sodium silicate, silica sol, tetraethyl orthosilicate, water glass and chromatography silica gel.

15. Use of the ZSM-5 molecular sieve catalyst according to claim 6 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that: The aluminum source is one or more of aluminum sulfate, sodium metaaluminate, aluminum isopropoxide and boehmite.

16. Use of the ZSM-5 molecular sieve catalyst according to claim 6 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that: The alkali source is one or more of sodium hydroxide, potassium hydroxide, barium hydroxide and sodium carbonate.

17. Use of the ZSM-5 molecular sieve catalyst according to claim 6 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that: The dispersant is a water-soluble surfactant.

18. Use of the ZSM-5 molecular sieve catalyst according to claim 6 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that: The dispersant is selected from one or more of sodium lauryl sulfate, sodium dodecylbenzenesulfonate and polyethylene glycol 400.

19. Use of the ZSM-5 molecular sieve catalyst according to claim 6 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that The crystallization temperature is 100-180° C., and the crystallization time is 12-72 h.

20. Use of the ZSM-5 molecular sieve catalyst according to claim 6 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that: In the hydrothermal crystallization step, the solution is transferred to a hydrothermal kettle and then placed in a rotary oven at a rotation speed of 5 to 100 rpm.

21. Use of the ZSM-5 molecular sieve catalyst according to claim 1 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that: The catalytic cyclohexene preparation of cyclohexanol is to mix cyclohexene and water to carry out hydration reaction to prepare cyclohexanol. Wherein, the molar ratio of water to cyclohexene is (0.5-10):

1.

22. Use of the ZSM-5 molecular sieve catalyst according to claim 21 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that: The molar ratio of water to cyclohexene is (1-8):

1.

23. Use of the ZSM-5 molecular sieve catalyst according to claim 22 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that: The molar ratio of water to cyclohexene is 8:1, 6.8:1, 5:1, 4:1, 3.5:1, 3:1, 2.5:1, 2:1, 1.5:1, and 1:

1.

24. Use of the ZSM-5 molecular sieve catalyst according to claim 23 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that: The mass ratio of the ZSM-5 molecular sieve catalyst to cyclohexene is (0.1-2.0):

1.

25. Use of the ZSM-5 molecular sieve catalyst according to claim 23 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that: The mass ratio of the ZSM-5 molecular sieve catalyst to cyclohexene is 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, and 2.0:

1.

26. Use of the ZSM-5 molecular sieve catalyst according to claim 21 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that: The temperature of the hydration reaction is 100~140℃.

27. Use of the ZSM-5 molecular sieve catalyst according to claim 21 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that: The temperature of the hydration reaction is 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, and 140°C.

28. Use of the ZSM-5 molecular sieve catalyst according to claim 27 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that The pressure of the hydration reaction is 0.1~1 MPa.

29. Use of the ZSM-5 molecular sieve catalyst according to claim 28 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that: The pressure of the hydration reaction is 0.1MPa, 0.2MPa, 0.3MPa, 0.4MPa, 0.5MPa, 0.6MPa, 0.7MPa, 0.8MPa, 0.9MPa, and 1.0MPa.

30. Use of the ZSM-5 molecular sieve catalyst according to claim 21 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that The hydration reaction time is 0.5~3 h.

31. Use of the ZSM-5 molecular sieve catalyst according to claim 30 in catalyzing the production of cyclohexanol from cyclohexene, characterized in that The hydration reaction time was 0.5 h, 0.8 h, 1.0 h, 1.2 h, 1.4 h, 1.6 h, 1.8 h, 2.0 h, 2.2 h, 2.4 h, 2.5 h, 2.6 h, 2.8 h, and 3.0 h.

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