CN101342496B - Preparation method of zirconium silicon molecular sieve catalytic active film - Google Patents

Abstract

The invention provides a method for preparing zirconium molecular sieve catalytic active film, including the procedures of carrier treatment, preparation of molecular-sieve precursor collosol, hydrothermal crystallization and preparation of zirconium molecular sieve catalytic active film. The zirconium molecular sieve catalytic active film prepared by the method is used to catalyze the selective oxidation of isopropanol and the epoxidation reaction of micromolecule olefin; the experiment result shows that the flux is 0.16kg/m2 per h when the mass concentration of isopropyl at the feed side is10 percent, the conversion rate of catalytic reaction is 63 percent; with regard to vinyl chloride reaction system, the conversion can be as high as 62 percent. The zirconium molecular sieve catalytic active film prepared by such method has relatively high catalytic activity. The invention has the advantages of that the method is simple, the product cost is low, the conversion rate is high, etc.,and the zirconium molecular sieve catalytic active film prepared by such method can be applied to the selective catalytic oxidation reaction of alcohol and low-carbon olefin.

Description

Preparation method of zirconium silicon molecular sieve catalytic active film

technical field

The invention belongs to the technical field of inorganic membrane materials, and in particular relates to zirconium-silicon molecular sieve membranes.

Background technique

Molecular sieves have a regular pore structure, large specific surface area and pore volume, and have been used as catalytic materials, gas separation and adsorbents, ion exchangers, etc., and are widely used in oil and natural gas processing, fine chemicals, environmental protection and nuclear waste treatment, etc. field. Compared with homogeneous catalysts, molecular sieve solids are used as catalysts, which have high catalytic efficiency, good hydrothermal stability, and can be recycled and reused. However, due to the small size of molecular sieve catalysts, most of which are nano-scale powders, there are disadvantages such as difficult recovery, easy deactivation and aggregation. In practical applications, due to the high pressure drop, zeolite molecular sieve powders are not suitable for catalytic reactions. In a fixed bed reactor, it is necessary to add a binder to form particles with a certain mechanical strength and shape to suit various applications. In addition, for some chain reactions, it is difficult to control the reaction to obtain intermediate products. However, fixing nano-scale molecular sieve catalysts on porous tubular or porous plates to form dense crystal membranes can not only solve the problem of catalyst recovery, but also avoid deep reactions, and can combine the characteristics of membrane separation to separate products and reactants. . Therefore, the production cost is greatly reduced and the production process is simplified. At present, membrane reactors have the characteristics of higher product yield, better selectivity and less by-products than traditional packed bed reactors.

There are many types of molecular sieve membrane reactors, which can be divided into catalytically inert membrane reactors and catalytically active membrane reactors according to the role played by molecular sieve membranes in the reaction. At present, more researches are on catalytic inert membrane reactors. In this reactor, the catalyst is separated from the molecular sieve membrane, and the molecular sieve membrane has only the separation function. This kind of membrane reactor is mostly used for esterification reaction and dehydrogenation reaction. For example, the high hydrophilicity of the membrane is used to selectively remove the water produced by the esterification reaction, so that this equilibrium reaction can proceed to the right, and the conversion rate of the reactant can be increased. NaA molecular sieve membrane can effectively remove the water generated in the esterification reaction of ethanol and oleic acid, methanol and oleic acid, lactic acid and ethanol. Inert molecular sieve membrane reactors are also commonly used in partial oxidation reactions, where their main role is to control the amount of reactants. For example, the MFI molecular sieve membrane reactor is used in the partial oxidation of n-butane to maleic anhydride, (VO) ₂ P ₂ O ₇ is used as a catalyst, and the injection amount of oxygen and n-butane is controlled through the MFI molecular sieve membrane, which greatly improves conversion and selectivity of the reaction.

Because some molecular sieves have catalytic activity, the prepared molecular sieve membrane can be used as a molecular sieve catalytically active membrane reactor for various catalytic reactions. In recent years, ZSM-5 molecular sieve catalytically active membrane has been successfully used as a membrane reactor in the reaction of methanol to olefins. Because methanol is catalyzed by ZSM-5 molecular sieve catalyst, a chain reaction occurs, methanol → dimethyl ether → olefin → paraffin + aromatic hydrocarbon. If a traditional ZSM-5 molecular sieve catalyst is used in a packed bed reactor, since the molecules can repeatedly diffuse into the catalyst particles and contact the active center, the reaction will continue continuously, and the yield of the intermediate product olefins is low and the selectivity is poor. However, with ZSM-5 molecular sieve catalytic active membrane reactor, under the drive of the pressure difference on both sides of the membrane, methanol reacts in the membrane layer, and the products produced are different with the depth of the membrane layer. Alkenes can be obtained with high selectivity by effectively adjusting the diffusion rate of molecules in the membrane layer. On the permeation side of the membrane, the selectivity of olefins is as high as 80% to 90%, and the conversion rate of methanol is also as high as 60% to 98%. Another example of successfully applying molecular sieve catalytically active membranes as membrane reactors is H-ZSM-5 molecular sieve catalytically active membranes. H-ZSM-5 molecular sieve catalytically active membrane was applied to the esterification reaction of ethanol and acetic acid. When ethanol and acetic acid molecules pass through the membrane layer, H-ZSM-5 molecular sieve acts as a catalyst to catalyze the reaction to proceed rapidly. At the same time, due to the strong hydrophilicity of the H-ZSM-5 molecular sieve membrane, it can selectively generate The water is removed, thereby greatly improving the conversion rate of the reaction. Compared with traditional H-ZSM-5 molecular sieve packed bed reactor and H-ZSM-5 molecular sieve powder catalyst, the conversion rate of ethanol and acetic acid in H-ZSM-5 molecular sieve membrane reactor is much higher.

Zirconium-silicon molecular sieve powder is a good catalyst and can be used in selective catalytic oxidation reactions. However, the application of zirconium-silicon molecular sieve catalytic active membranes as membrane reactors has not been reported.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for preparing a zirconium-silicon molecular sieve catalytically active membrane with simple method, low product cost and high conversion rate.

The technical solution adopted to solve the problems of the technologies described above is that it comprises the following steps:

A method for preparing a zirconium-silicon molecular sieve catalytically active membrane, characterized in that it comprises the following steps:

(1) Carrier treatment

Grind the mullite tube or α-Al ₂ O ₃ tube carrier with sandpaper, clean it for 10 minutes with an ultrasonic wave with a power of 200W and a frequency of 40Hz, and place it in a 1800W electric heating constant temperature blast drying oven at 100°C for 4 hours. Cool down to room temperature, take it out of the electric constant temperature blast drying oven, and fix it in a high-pressure hydrothermal synthesis reaction kettle with a _{polytetrafluoroethylene liner} . Vinyl fluoride tape seal;

The above-mentioned mullite tube or α-Al ₂ O ₃ tube has an average pore diameter of 7 μm, a porosity of 50%, an outer diameter of 12.5 mm, and a wall thickness of 2 mm;

(2) Preparation of molecular sieve precursor sol

Under stirring at a speed of 700 rpm, tetraethylorthosilicate, tetrabutoxyzirconium, tetrapropylammonium hydroxide, and water are mixed in a molar ratio of 1:0.01～0.02:0.20～0.35:25～55 Mix to make the precursor sol of zirconium silicon molecular sieve;

(3) Hydrothermal crystallization

Pour the precursor sol into a high-pressure hydrothermal synthesis reactor equipped with a mullite tube or α-Al ₂ O ₃ tube carrier, seal it, and place it in an electric constant temperature blast drying oven with a preset temperature for static hydrothermal crystallization , the static hydrothermal crystallization temperature is 150°C, and the crystallization time is 80 hours;

(4) Preparation of zirconium silicon molecular sieve catalytic active membrane

Take out the high-pressure hydrothermal synthesis reaction kettle, cool naturally or with water to room temperature, take out the molecular sieve membrane containing the template agent, wash it with secondary water at 100°C for 1 hour, put it in a 1800W electric constant temperature blast drying oven at 100°C for 12 hours, Place in a 5000W muffle furnace, heat up to 550°C at 0.5°C/min, bake for 5-6 hours to remove the template agent, cool down to room temperature at 0.5°C/min, and prepare a zirconium-silicon molecular sieve membrane.

2, according to the preparation method of the said zirconium silicon molecular sieve catalytic active film of claim 1, it is characterized in that: in preparation molecular sieve precursor sol process step (2), said tetraethyl orthosilicate and tetrabutoxy The molar ratio of zirconium base, tetrapropyl ammonium hydroxide and water is 1:0.012～0.017:0.27～0.32:30～50.

3. According to the preparation method of the said zirconium silicon molecular sieve catalytically active membrane of claim 1, it is characterized in that: in the preparation step (2) of the molecular sieve precursor sol process, said tetraethylorthosilicate and tetrabutoxy The molar ratio of zirconium base, tetrapropyl ammonium hydroxide and water is 1:0.015:0.30:40.

4. According to the preparation method of the zirconium-silicon molecular sieve catalytically active membrane according to claim 1, it is characterized in that said carrier treatment process step (1) is: passing mullite tube or α-Al ₂ O ₃ tube carrier through sandpaper Polish, clean with 200W power and 40Hz ultrasonic wave for 10 minutes, place in a 1800W electric heating constant temperature blast drying oven at 100°C for 4 hours, cool down to room temperature, take it out, and carry out seed crystallization treatment by hand coating or dip coating , fixed in a high-pressure hydrothermal _synthesis reactor containing a polytetrafluoroethylene liner, and the two ends of the mullite tube or α- _Al2O3 tube support were sealed with polytetrafluoroethylene tapes.

5. Packaging

Wrap it in toilet paper and place it in a desiccator.

In step 2 of the process for preparing molecular sieve precursor sol of the present invention, the preferred molar ratio of tetraethylorthosilicate to tetrabutoxyzirconium, tetrapropylammonium hydroxide, and water is 1: 0.012～0.017: 0.27～0.32 : 30-50.

In step 2 of the process for preparing the molecular sieve precursor sol of the present invention, the optimum molar ratio of tetraethylorthosilicate to tetrabutoxyzirconium, tetrapropylammonium hydroxide and water is 1:0.015:0.30:40.

The zirconium-silicon molecular sieve catalytic active membrane prepared by the present invention is used to catalyze the selective oxidation of isopropanol and the epoxidation reaction of small molecular olefins. The experimental results show that when the feed side isopropanol mass concentration is 10%, the flux is 0.16kg/m ² ·h, the catalytic oxidation reaction conversion rate is 63%, and for the vinyl chloride reaction system, the conversion rate of vinyl chloride can also reach 62%. The catalytically active zirconium-silicon molecular sieve membrane prepared by the invention has good catalytic activity and can be used for the selective catalytic oxidation reaction of alcohols and low-carbon olefins.

Description of drawings

Fig. 1 is an X-ray diffraction curve of a zirconium-silicon molecular sieve catalytically active membrane prepared in Example 1 of the present invention.

Fig. 2 is the infrared spectrum curve of the zirconium-silicon molecular sieve catalytically active membrane prepared in Example 1 of the present invention.

Fig. 3 is a scanning electron micrograph of the surface of the catalytically active membrane of zirconium-silicon molecular sieve prepared in Example 1 of the present invention.

Fig. 4 is a scanning electron micrograph of a cross-section of a zirconium-silicon molecular sieve catalytically active membrane prepared in Example 1 of the present invention.

Fig. 5 is a structural schematic diagram of an experimental device for catalytic reaction of a zirconium-silicon molecular sieve catalytic active membrane.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments, but the present invention is not limited to these embodiments.

Example 1

Taking the total amount of raw materials used to prepare the zirconium-silicon molecular sieve catalytically active membrane as an example, the preparation method is as follows:

1. Carrier processing

The porous ceramic tube of this embodiment uses a mullite tube as a carrier. The average pore diameter of the mullite tube is 7 μm, the porosity is 50%, the outer diameter is 12.5 mm, and the wall thickness is 2 mm. Grind the mullite tube with 600-mesh sandpaper, clean it with a 200W ultrasonic wave at a frequency of 40Hz for 10 minutes, place it in a 1800W electric heating constant temperature blast drying oven and dry it at 100°C for 4 hours, then cool it down to room temperature. Take it out from the drying oven, and fix it in a high-pressure hydrothermal synthesis reaction kettle with a polytetrafluoroethylene liner, and the two ends of the porous ceramic tube carrier are sealed with polytetrafluoroethylene tapes.

2. Preparation of molecular sieve precursor sol

Take 68.381g of tetraethylorthosilicate with a mass concentration of 98%, 2.31g of tetrabutoxyzirconium with a mass concentration of 80%, 93.838g of tetrapropylammonium hydroxide with a mass concentration of 20.9%, and 155.471g of water. In the flask, the molar ratio of tetrabutoxy zirconium and tetraethyl orthosilicate, tetrapropyl ammonium hydroxide, water is 1: 0.015: 0.30: 40, will be fully mixed under the stirring speed of 700 rpm, The precursor sol of zirconium silicate molecular sieve is made.

3. Hydrothermal crystallization

Pour the precursor sol into a high-pressure hydrothermal synthesis reaction kettle equipped with a porous ceramic tube carrier, seal it, and place it in an electric constant temperature blast drying oven with a preset temperature for static hydrothermal crystallization. The temperature of static hydrothermal crystallization is 150°C, the crystallization time is 80 hours.

4. Preparation of zirconium silicon molecular sieve catalytic active membrane

Take out the high-pressure hydrothermal synthesis reaction kettle, cool naturally or with water to room temperature, take out the molecular sieve membrane containing the template agent, wash it with secondary water at 100°C for 1 hour, put it in a 1800W electric constant temperature blast drying oven at 100°C for 12 hours, Place in a 5000W muffle furnace, heat up to 550°C at 0.5°C/min, bake for 5.5 hours to remove the template agent, cool down to room temperature at 0.5°C/min, and prepare a zirconium-silicon molecular sieve catalytic active membrane

5. Packaging

Wrap it in toilet paper and place it in a desiccator.

Example 2

Taking the total amount of raw materials used to prepare the zirconium-silicon molecular sieve catalytically active membrane as an example, the preparation method is as follows:

In step 1 of the carrier treatment process, the porous ceramic tube of this embodiment uses a mullite tube as a carrier. The average pore diameter of the mullite tube is 0.1 μm, the porosity is 30%, the outer diameter is 10 mm, and the wall thickness is 1 mm. Other steps in this processing step are identical with embodiment 1. In step 2 of preparing the zirconium-silicon molecular sieve precursor sol process, 96.813g of tetraethylorthosilicate with a mass concentration of 98%, 2.181g of tetrabutoxyzirconium with a mass concentration of 80%, and 20.9% of Add 88.569g of tetrapropylammonium hydroxide and 132.437g of water into the flask, and fully mix them under stirring at a speed of 700 rev/min. The molar ratio is 1:0.01:0.2:25, and the zirconium-silicon molecular sieve precursor sol is prepared. In step 3 of the crystallization process, the zirconium-silicon molecular sieve precursor sol is poured into a high-pressure hydrothermal synthesis reaction kettle equipped with a mullite tube carrier, the high-pressure hydrothermal synthesis reaction kettle is sealed, and placed in a 1800W electric heating constant temperature blast drying Static hydrothermal crystallization in the box, crystallization at 140°C for 100 hours, to prepare a molecular sieve membrane containing a template. In step 4 of the process for preparing a zirconium-silicon molecular sieve catalytically active membrane, the molecular sieve membrane containing the template is placed in a 5000W muffle furnace, heated to 550°C at 0.5°C/min, and roasted for 5 hours to remove the template. In this process step The other steps are the same as in Example 1. The other process steps are the same as in Example 1 to prepare a zirconium-silicon molecular sieve catalytically active membrane.

Example 3

Taking the total amount of raw materials used to prepare zirconium-silicon catalytically active molecular sieve membranes as 320g as an example, the preparation method is as follows:

In step 1 of the carrier treatment process, the porous ceramic tube of this embodiment uses a mullite tube as a carrier. The average pore diameter of the mullite tube is 10 μm, the porosity is 60%, the outer diameter is 13 mm, and the wall thickness is 3 mm. Other steps in this processing step are identical with embodiment 1. In the process step 2 of preparing zirconium silicon molecular sieve precursor sol, take 53.279g of tetraethylorthosilicate with a mass concentration of 98%, 2.400g of tetrabutoxyzirconium with a mass concentration of 80%, and 20.9% of Add 48.742g of tetrapropylammonium hydroxide and 215.579g of water into the flask, and mix thoroughly under stirring at a speed of 700 rpm, tetraethyl orthosilicate, tetrabutoxyzirconium, tetrapropylammonium hydroxide, water massage The molar ratio is 1:0.02:0.35:55 to prepare zirconium silicon molecular sieve precursor sol. In step 3 of the hydrothermal crystallization process, the zirconium-silicon molecular sieve precursor sol is poured into a high-pressure hydrothermal synthesis reaction kettle equipped with a mullite tube carrier, the high-pressure hydrothermal synthesis reaction kettle is sealed, and placed in a 1800W electric heating constant temperature drum Static hydrothermal crystallization in an air drying oven, crystallization at 160°C for 72 hours, to prepare a molecular sieve membrane containing a template. In the preparation of catalytically active zirconium-silicon molecular sieve membrane 4, the molecular sieve membrane containing the template is placed in a 5000W muffle furnace, heated to 550°C at 0.5°C/min, and roasted for 6 hours to remove the template. Others in this process step Step is identical with embodiment 1. The other process steps are the same as in Example 1 to prepare a zirconium-silicon molecular sieve catalytically active membrane.

Example 4

Taking the total amount of raw materials used to prepare the zirconium-silicon molecular sieve catalytically active membrane as an example, the preparation method is as follows:

In the carrier treatment process step 1 of the above Examples 1-3, the porous ceramic tube used is an α-Al ₂ O ₃ tube, and the geometry of the α-Al ₂ O ₃ tube is the same as that of the mullite tube in the corresponding embodiment. Similarly, other steps in the process steps are the same as those in the corresponding embodiment. Other process steps are the same as those in the corresponding examples, and a catalytically active zirconium-silicon molecular sieve membrane is prepared.

Example 5

Taking the total amount of raw materials used to prepare the zirconium-silicon molecular sieve catalytically active membrane as an example, the preparation method is as follows:

In the carrier treatment process step 1 of the above examples 1-4, the porous ceramic tube carrier is polished with sandpaper, cleaned with ultrasonic waves with a power of 200W and a frequency of 40Hz for 10 minutes, and placed in a 1800W electric heating constant temperature blast drying oven at 100°C Dry for 4 hours, cool down to room temperature, take it out, carry out seed crystallization treatment by hand coating or dip coating, and fix it in a high-pressure hydrothermal synthesis reaction kettle with a polytetrafluoroethylene lining. Fluoroethylene tape seal. The other process steps are the same as those in the corresponding examples, and a zirconium-silicon molecular sieve catalytically active membrane is prepared.

In order to verify the beneficial effect of the present invention, the contriver adopts the zirconium-silicon molecular sieve catalytic active membrane prepared by the embodiment of the present invention 1 to test, and various tests are as follows:

Test instrument: X-ray diffractometer, model is Rigaku D/Max2550VB+/PC, produced by Rigalcu, Japan; Fourier transform infrared spectrometer, model is EQUINX, produced by German Brucher Company; scanning electron microscope, model is Quanta 200, produced by FEI company .

1. Characterization of Zirconium Silica Molecular Sieve Catalytic Active Membrane

The X-ray diffraction curve of the zirconium-silicon molecular sieve catalytically active membrane prepared in Example 1 of the present invention is shown in Figure 1, the infrared spectrum curve is shown in Figure 2, and the scanning electron microscope photos are shown in Figures 3 and 4.

In Fig. 1, curve a is the X-ray diffraction spectrum of zirconium-silicon molecular sieve catalytic active membrane, curve b is the X-ray diffraction spectrum of accompanying molecular sieve crystal, and curve c is the X-ray diffraction of mullite tube carrier spectrogram. It can be seen from Fig. 1 that the characteristic peaks at 8.5° and 24.4° clearly prove that the obtained zirconium-silicon molecular sieve membrane and its accompanying powder all have MFI structure. It can be seen from Figure 2 that the shoulder peak at 960cm ^-1 indicates that zirconium atoms have entered into the framework of the MFI structure, forming a Zr-O-Si structure. It can be seen from Fig. 3 that the surface of the mullite tube carrier is covered by catalytically active zirconium-silicon molecular sieve crystals, the crystals are small in size and the average particle size is 1-2 μm. It can be seen from Figure 4 that the thickness of the catalytically active film of zirconium-silicon molecular sieve is very thin and can hardly be measured, and most of the crystals grow in the pores of the carrier.

2. Catalyzing the selective oxidation of isopropanol and the epoxidation of small molecular olefins with zirconium-silicon molecular sieve catalytic active membrane

The reaction system solution is installed in a glass container 5 with a reflux condenser 1 , and then placed in a water bath 4 fixed on a magnetic stirrer 6 . One end of the zirconium-silicon molecular sieve catalytically active membrane 8 is connected to a polytetrafluoroethylene rod 7 with an outer diameter of 12 mm and a length of 2 cm to plug the opening, and the other end of the zirconium-silicon molecular sieve catalytically active membrane 8 passes through a 12 mm outer diameter and a length of 3 to 3 cm. A 4 cm glass tube is connected to the vacuum system 3 . The outer side of the zirconium silicon molecular sieve catalytically active membrane 8 is in contact with the reaction system solution, and the inner side is vacuumed at 25-45 Pa. When the reactant molecules pass through the zirconium-silicon molecular sieve catalytic active membrane 8 from the reaction system solution, the catalytic oxidation reaction occurs, and the reaction products and unreacted substances pass through the carrier layer through the process of permeating steam, and are collected in the cold trap 2 by cooling with liquid nitrogen. Two cold traps 2 can be used for alternate and continuous testing. The concentration of each component in the reaction system solution and the collected liquid was determined by gas chromatography analysis. The total flux is calculated as follows:

Q(kg/m ² h)=total mass of collected liquid/(collection time×membrane area)

In the formula, Q is the total flux, the mass collected on the permeate side through the pervaporation process per unit time and unit area; the total mass collected is obtained by weighing the mass of the liquid collected in the cold trap 2 with a balance. The collection time is the time elapsed from the start of the pervaporation process to the sample collection from the cold trap 2; the area of the zirconium-silicon molecular sieve catalytically active membrane 8 is the area of the membrane in contact with the reaction system solution during the pervaporation process. The catalytically active membrane 8 of the zirconium-silicon molecular sieve used in this experiment has an area of 22.6 cm ² . The conversion rate of the reaction is calculated according to the formula

C=M _product /(M _product +M _{unreacted matter} )×100%,

In the formula, C is conversion rate, and M _product is the mole number of the product that the reaction that collects in cold trap 2 generates, and M _{unreacted matter is} the mole number of unreacted matter collected in cold trap 2, and the size of conversion rate is to evaluate zirconium silicon Molecular sieve catalytic active membrane 8 is the main parameter of catalytic performance.

For the oxidation reaction of isopropanol, the molar concentration of reactant isopropanol in the reaction system solution is 1.667mol/L, the molar concentration of oxidant hydrogen peroxide is 1.667mol/L, water is used as the reaction solvent, and the reaction temperature is 60°C. When the components of this system pass through the zirconium-silicon molecular sieve catalytic active membrane 8 under pervaporation conditions, the following reactions occur:

CH ₃ CH(OH)CH ₃ +H ₂ O ₂ →CH ₃ COCH ₃ +2H ₂ O

The test results are shown in Table 1.

Table 1 Zirconium-silicon molecular sieve catalytic active membrane 8 is used for the catalytic oxidation reaction results of isopropanol

For the epoxidation reaction of vinyl chloride, the molar concentration of reactant vinyl chloride in the reaction system solution is 0.667mol/L, the molar concentration of oxidant hydrogen peroxide is 0.667mol/L, methanol is used as the reaction solvent, and the reaction temperature is 50°C. When the components of this system pass through the zirconium-silicon molecular sieve catalytic active membrane 5 under pervaporation conditions, the following reactions occur:

_ClCHCH2 + _H2O2 → _ClCHOCH + _2H2O

The test results are shown in Table 2.

Table 2 Zirconium-silicon molecular sieve catalytic active membrane 8 is used for vinyl chloride epoxidation reaction results

It can be seen from Table 1 and Table 2 that when the mass concentration of isopropanol on the feed side is 10%, the flux is 0.16kg/m ² h, and the catalytic oxidation reaction conversion rate is 63%. For the vinyl chloride reaction system, the vinyl chloride The conversion rate can also reach 62%. The zirconium-silicon molecular sieve catalytic active membrane prepared by the invention has good catalytic activity and can be used for the selective catalytic oxidation reaction of alcohols and low-carbon olefins.

Claims (4)

1. the preparation method of a zirconium-silicon molecular sieve catalytic active membrane is characterized in that it comprises the steps:

(1) vehicle treated

With mullite pipe or α-Al ₂O ₃The pipe carrier is through sand papering, with power is that the ultrasonic frequency of 200W is that the ultrasonic wave of 40Hz cleaned 10 minutes, place 100 ℃ of dryings of electric heating constant temperature air dry oven 4 hours of 1800W, reduce to room temperature, from the electric heating constant temperature air dry oven, take out, be fixed in the water under high pressure thermal synthesis reactor that contains teflon lined mullite pipe or α-Al ₂O ₃The two ends of pipe carrier seal with teflin tape;

Above-mentioned mullite pipe or α-Al ₂O ₃The average pore size of pipe is that 7 μ m, porosity are 50%, external diameter is 12.5mm, and wall thickness is 2mm;

(2) preparation molecular sieve precursor colloidal sol

Under 700 rev/mins rotating speeds stir with tetraethyl orthosilicate ester, tetrabutyl zirconate, TPAOH, hydromassage you than being 1: 0.01～0.02: 0.20～0.35: 25～55 fully mixing, make the precursor colloidal sol of zirconium-silicon molecular sieve;

(3) hydrothermal crystallizing

Precursor colloidal sol poured into mullite pipe or α-Al are housed ₂O ₃Seal behind the water under high pressure thermal synthesis reactor of pipe carrier, place the electric heating constant temperature air dry oven static hydrothermal crystallization that presets temperature, the temperature of static hydrothermal crystallization is 150 ℃, and crystallization time is 80 hours;

(4) preparation zirconium-silicon molecular sieve catalytic active membrane

Take out water under high pressure thermal synthesis reactor, naturally the cooling or with being water-cooled to room temperature, taking-up contains the molecular screen membrane of template agent, with 100 ℃ in secondary water washing 1 hour, put into 100 ℃ of dryings of electric heating constant temperature air dry oven 12 hours of 1800W, place the Muffle furnace of 5000W, be warming up to 550 ℃ with 0.5 ℃/minute, the template agent was removed in roasting in 5～6 hours, was cooled to room temperature with 0.5 ℃/minute, was prepared into zirconium-silicon molecular sieve film.

2. according to the preparation method of the said zirconium-silicon molecular sieve catalytic active membrane of claim 1, it is characterized in that: in preparation molecular sieve precursor collosol craft step (2), the mol ratio of said tetraethyl orthosilicate ester and tetrabutyl zirconate, TPAOH, water is 1: 0.012～0.017: 0.27～0.32: 30～50.

3. according to the preparation method of the said zirconium-silicon molecular sieve catalytic active membrane of claim 1, it is characterized in that: in preparation molecular sieve precursor collosol craft step (2), the mol ratio of said tetraethyl orthosilicate ester and tetrabutyl zirconate, TPAOH, water is 1: 0.015: 0.30: 40.

4. according to the preparation method of the described zirconium-silicon molecular sieve catalytic active membrane of claim 1, it is characterized in that said vehicle treated processing step (1) is: with mullite pipe or α-Al ₂O ₃The pipe carrier is through sand papering, is that the ultrasonic wave of 40Hz cleaned 10 minutes with power for the 200W frequency, place 100 ℃ of dryings of electric heating constant temperature air dry oven 4 hours of 1800W, reduce to room temperature, take out, be coated with method or dip coating carries out kind of a crystallization treatment with hand, be fixed in the water under high pressure thermal synthesis reactor that contains teflon lined mullite pipe or α-Al ₂O ₃The two ends of pipe carrier seal with teflin tape.

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