Binderless ZSM-35 molecular sieve catalyst, its preparation method and application

Abstract

The present invention discloses a binderless ZSM-35 molecular sieve catalyst, a preparation method thereof, and an application thereof. In the binderless ZSM-35 molecular sieve catalyst, based on the weight of aluminum in the catalyst, the content of framework aluminum is 58% to 82%, and the content of non-framework aluminum is 18% to 42%. When this catalyst is used in the skeletal isomerization reaction of C4 olefins, it has a higher yield of the target product isobutene and good long-term stability.

Description

Technical Field

[0001] The invention relates to the field of olefin skeletal isomerization, and in particular to a binder-free ZSM-35 molecular sieve catalyst for n-butene skeletal isomerization and a preparation method thereof, as well as application of the catalyst in n-butene skeletal isomerization reaction. Background Art

[0002] With the rapid development of oil refining and petrochemical industries, the processing and utilization of C4 resources have gradually received more attention. Isobutylene is a widely used C4 component that can be used to produce MTBE blended gasoline, or to produce high-purity isobutylene products, and can also produce many high-value-added fine chemical products such as polyisobutylene. Therefore, converting n-butene into isobutylene through skeletal isomerization reaction has good application value.

[0003] The technology of isomerization of n-butene to isobutylene emerged in the 1970s. In the early days, oxide catalysts such as alumina were mainly used. In the 1990s, the market demand for isobutylene increased sharply. At the same time, the discovery of molecular sieve catalysts led to the rapid development of the n-butene skeletal isomerization process. The molecular sieve catalytic process uses molecular sieves such as silicon-aluminum ZSM type and phosphorus-silicon-aluminum SAPO type as catalysts for the skeletal isomerization of n-butene, and its activity is more ideal than that of traditional oxides. The research results of the past three decades have shown that FER molecular sieve catalysts with ten-membered ring channels and special FER cages are more suitable for the skeletal isomerization reaction of linear olefins.

[0004] The method for preparing isobutylene by skeletal isomerization of n-butene disclosed in CN103772112A uses a sodium potassium hydrogen type FER molecular sieve with a SiO2 / Al2O3 molar ratio of 10 to 50 as a catalyst. The preparation method is to mix and form the sodium potassium hydrogen type FER molecular sieve, a binder, an extrusion aid, an inorganic acid and water to prepare the catalyst. Although the use of the catalyst can make the yield reach a stable period in a short time, the yield of the target product isobutylene is still low and needs to be further improved.

[0005] The catalyst needs to add a certain amount of binder during the molding process, and the binder-free catalyst converts this part of the binder into an effective component of a molecular sieve, so that the catalyst does not contain a binder or contains only a small amount of binder. Therefore, the binder-free catalyst has a higher molecular sieve content per unit volume, the catalyst activity is higher, the processing load is larger, and there is no binder blocking the pores, the catalyst utilization efficiency is higher, and the anti-carbon deposition ability is stronger. CN109701606A discloses a skeleton isomerization catalyst, which includes: 95.5-100% molecular sieve (such as ZSM-35 molecular sieve), 0-4.5% binder by weight percentage. The preparation method is to obtain a precursor by mixing molecular sieve powder and binder, converting the binder into molecular sieve by hydrothermal reaction, exchanging ammonium, and roasting to obtain a binder-free catalyst.

[0006] For the n-butene skeletal isomerization reaction, developing catalysts with higher activity, selectivity, and better stability, as well as their simple preparation methods, is a technical problem that has been continuously addressed in this field. Summary of the Invention

[0007] In view of the problems in the prior art, such as poor stability of the n-butene skeletal isomerization catalyst and low yield of the target product, a new binderless ZSM-35 molecular sieve catalyst for n-butene skeletal isomerization, its preparation method, and application are provided. When the binderless ZSM-35 molecular sieve catalyst is used for n-butene skeletal isomerization, it has the characteristics of high yield of the target product and excellent stability.

[0008] In the first aspect of the present invention, a binderless ZSM-35 molecular sieve catalyst is provided, wherein, based on the weight of aluminum in the catalyst, the content of framework aluminum is 58% - 82%, preferably 65% - 80%, and the content of non-framework aluminum is 18% - 42%, preferably 20% - 35%.

[0009] In the present invention, the aluminum in the catalyst is divided into framework aluminum and non-framework aluminum.

[0010] According to some embodiments of the present invention, the total acid amount of the catalyst is 0.40 - 0.70 mmol·g -1 , preferably 0.45 - 0.70 mmol·g -1 .

[0011] According to some embodiments of the present invention, in the catalyst, the content of medium-strong acid is 55% - 75%, and the content of strong acid is 25% - 45%; preferably, the content of medium-strong acid is 60% - 70%, and the content of strong acid is 30% - 40%.

[0012] In the present invention, for the binderless, based on the weight of the catalyst, the mass content of the binder is less than 5%, preferably less than 3%, and further preferably less than 2%.

[0013] According to some embodiments of the present invention, the specific surface area of the catalyst is 250 - 350 m 2 ·g -1 , preferably 270 - 320 m 2 ·g -1 ; the pore volume is 0.1 - 0.3 cm 3 ·g -1 ; the average pore diameter is 2.0 - 5.0 nm.

[0014] According to some embodiments of the present invention, the SiO2 / Al2O3 molar ratio of the catalyst is 10 - 30, preferably 15 - 25; the mass content of Na2O ≤ 0.03%.

[0015] According to some embodiments of the present invention, the radial crushing strength of the catalyst is 4 to 10 N·mm -1 , preferably 5 to 8 N·mm -1 .

[0016] The second aspect of the present invention provides a method for preparing a binderless ZSM-35 molecular sieve catalyst, comprising:

[0017] a) Mixing a silicon source, an aluminum source, a first alkali source, a binder precursor, and an auxiliary agent, forming, first drying, and first calcining to obtain a precursor;

[0018] b) Mixing a solution containing a second alkali source and a template agent with the precursor obtained in step a), performing hydrothermal crystallization, second drying, and second calcining to obtain a catalyst intermediate;

[0019] c) After subjecting the catalyst intermediate obtained in step b) to ammonium exchange, performing steam treatment to obtain a binderless ZSM-35 molecular sieve catalyst.

[0020] According to some embodiments of the present invention, the silicon source in step a) is fumed silica. The aluminum source is one or more of sodium aluminate, aluminum sulfate, kaolin, and pseudoboehmite. The first alkali source is one or more of sodium carbonate and potassium carbonate. The binder is amorphous silica, and the binder precursor is silica sol. The auxiliary agent is one or more of talc powder, cellulose, and starch.

[0021] According to some embodiments of the present invention, the forming in step a) can adopt a conventional forming method, such as extrusion forming. The conditions for the first drying are as follows: the first drying temperature is 80 to 200 °C, and the first drying time is 12 to 48 h. The conditions for the first calcining are as follows: the first calcining temperature is 400 to 600 °C, and the first calcining time is 3 to 12 h. The first drying and the first calcining are both carried out in an oxygen-containing atmosphere, such as air.

[0022] According to some embodiments of the present invention, the second alkali source in step b) is one or more of sodium hydroxide and potassium hydroxide. The template agent is one or more of cyclohexylamine, n-butylamine, 1,4-cyclohexanediamine, and ethylenediamine.

[0023] According to some embodiments of the present invention, in the solution containing the second alkali source and the template agent in step b), the mass concentration of the second alkali source is 1% to 3%, and the mass concentration of the template agent is 3% to 15%.

[0024] According to some embodiments of the present invention, in step a), a silicon source, an aluminum source, a first alkali source, a binder precursor, and an auxiliary agent are mixed. Among them, the silicon source is calculated as SiO2, the aluminum source is calculated as Al2O3, and the first alkali source is calculated as oxide M2O. The material ratios of the silicon source, the aluminum source, and the first alkali source are as follows: the molar ratio of SiO2 to Al2O3 is 10-20:1, and the molar ratio of M2O to Al2O3 is 0.4-1.0:1. The dosage of the binder precursor, calculated as the binder, is 40%-60% of the total mass of the silicon source calculated as SiO2 and the aluminum source calculated as Al2O3, and the dosage of the auxiliary agent is 1%-5% of the total mass of the silicon source calculated as SiO2 and the aluminum source calculated as Al2O3.

[0025] According to some embodiments of the present invention, in step b), a solution containing a second alkali source and a template agent is mixed with the precursor obtained in step a). In the resulting mixture, the second alkali source is calculated as oxide M2O, and the molar ratio of M2O to the aluminum source calculated as Al2O3 in step a) is 0.30-0.6:1; the molar ratio of the template agent to the aluminum source calculated as Al2O3 in step a) is 1-6:1.

[0026] According to some embodiments of the present invention, the hydrothermal crystallization in step b) uses gradient temperature rising crystallization. The starting temperature is 80-140 °C, the termination temperature is 150-200 °C, and the total crystallization time is 48-192 h. Among them, the gradient temperature rising crystallization uses at least 2 gradients, further 2-10 gradients, the temperature difference between adjacent two gradients is at least 5 °C or more, further 10 °C or more, and preferably 10-30 °C. Further, the crystallization time for each gradient is 10-30 hours. The crystallization time for each gradient can be the same or different.

[0027] According to some embodiments of the present invention, after the hydrothermal crystallization in step b) is completed, it is preferably washed before the second drying, and deionized water can be used for washing. The conditions for the second drying are as follows: the drying temperature is 80-120 °C, and the drying time is 12-48 h. The conditions for the second calcination are as follows: the calcination temperature is 400-600 °C, and the calcination time is 3-12 h. Both the second drying and the second calcination are carried out in an oxygen-containing atmosphere, such as air.

[0028] According to some embodiments of the present invention, the ammonium exchange in step c) can be carried out by a conventional method, and the ammonium salt used can be one or more of ammonium nitrate, ammonium acetate, ammonium sulfate, etc. The mass concentration of the ammonium salt solution can be 5%-15%, and the conditions for ammonium exchange are as follows: the temperature is 30-90 °C, and the ammonium exchange time for each time is 0.5-2 h. The ammonium exchange can be carried out multiple times, further 2-6 times.

[0029] According to some embodiments of the present invention, the steam treatment process in step c) is carried out in a rotary tube furnace. Preferably, the rotation speed is ≥ 1 rpm, and further preferably 1 - 5 rpm.

[0030] According to some embodiments of the present invention, the conditions of the steam treatment in step c) are as follows: the mass space velocity of steam is 0.3 - 5 h -1 , preferably 0.5 - 3.0 h -1 ; the treatment temperature is 400 - 700 °C, preferably 450 - 600 °C; the treatment pressure is 0 - 1 MPa, preferably 0 - 0.5 MPa; the treatment time is 1 - 10 h, preferably 3 - 8 h.

[0031] According to some embodiments of the present invention, for the binderless ZSM-35 molecular sieve catalyst prepared by the method, based on the weight of aluminum in the catalyst, the content of framework aluminum is 58% - 82%, preferably 65% - 80%, and the content of non-framework aluminum is 18% - 42%, preferably 20% - 35%.

[0032] According to some embodiments of the present invention, the total acid amount of the binderless ZSM-35 molecular sieve catalyst prepared by the method is 0.40 - 0.70 mmol·g -1 , preferably 0.45 - 0.70 mmol·g -1 .

[0033] According to some embodiments of the present invention, in the binderless ZSM-35 molecular sieve catalyst prepared by the method, the content of medium-strong acid is 55% - 75%, and the content of strong acid is 25% - 45%; preferably, the content of medium-strong acid is 60% - 70%, and the content of strong acid is 30% - 40%.

[0034] According to some embodiments of the present invention, the specific surface area of the binderless ZSM-35 molecular sieve catalyst prepared by the method is 250 - 350 m 2 ·g -1 , preferably 270 - 320 m 2 ·g -1 ; the pore volume is 0.1 - 0.3 cm 3 ·g -1 ; the average pore diameter is 2.0 - 5.0 nm.

[0035] According to some embodiments of the present invention, the SiO2 / Al2O3 molar ratio of the binderless ZSM-35 molecular sieve catalyst prepared by the method is 10 - 30, preferably 15 - 25; the mass content of Na2O ≤ 0.03%.

[0036] According to some embodiments of the present invention, the radial crushing strength of the binderless ZSM-35 molecular sieve catalyst prepared by the method is 4-10 N·mm -1 , preferably 5-8 N·mm -1 .

[0037] The third aspect of the present invention also provides an application of the catalyst as described in the first aspect of the present invention or the catalyst prepared by the preparation method as described in the second aspect of the present invention in the skeletal isomerization reaction of C4 olefins.

[0038] According to some embodiments of the present invention, the C4 olefin is n-butene or a mixed hydrocarbon containing n-butene, and more preferably the mass content of diolefins such as 1,3-butadiene in the mixed hydrocarbon is less than 1%.

[0039] According to some embodiments of the present invention, the temperature of the reaction is 200-500 °C, preferably 300-450 °C.

[0040] According to some embodiments of the present invention, the pressure of the reaction is 0-1 MPa, preferably 0-0.5 MPa, and more preferably 0-0.2 MPa.

[0041] According to some embodiments of the present invention, the mass space velocity of the C4 olefin is 0.1-10 h -1 , preferably 0.5-6 h -1 .

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] 1. The inventors of the present invention have found through a large number of studies that by controlling the content of framework aluminum and non-framework aluminum in the binderless ZSM-35 molecular sieve catalyst, especially by controlling the total acid amount and acid amount distribution, for the skeletal isomerization reaction of C4 olefins, it has a higher isobutene yield. It can not only reach the stable period of high isobutene yield in a short time, but also maintain the stability for a long time, which can reach more than 1300 hours.

[0044] 2. The catalyst of the present invention synchronizes the preparation and shaping of ZSM-35 molecular sieve, and then obtains the binderless ZSM-35 molecular sieve catalyst through steam treatment under specific conditions. The preparation method of the catalyst of the present invention not only has a simple preparation method, does not require seeds, reduces the generation of pollution such as waste acid and waste alkali, has significant cost advantages and environmental protection advantages, but also the obtained catalyst has good isomerization activity and good stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 XRD spectra of catalyst intermediates Z-1 to Z-6 obtained in Examples 1-6;

[0046] Figure 2 SEM photograph of catalyst intermediate Z-1 obtained in Example 1;

[0047] Figure 3 SEM photograph of catalyst intermediate Z-2 obtained in Example 2;

[0048] Figure 4 SEM photograph of catalyst intermediate Z-3 obtained in Example 3;

[0049] Figure 5 SEM photograph of catalyst intermediate Z-4 obtained in Example 4;

[0050] Figure 6 SEM photograph of catalyst intermediate Z-5 obtained in Example 5;

[0051] Figure 7 SEM photograph of catalyst intermediate Z-6 obtained in Example 6;

[0052] Figure 8 NH3-TPD spectra of catalyst intermediates Z-1 to Z-6 obtained in Examples 1-6;

[0053] Figure 9 NH3-TPD spectra of catalyst Z-1-7 obtained in Example 7, catalyst Z-1-12 obtained in Example 12, catalyst Z-2-20 obtained in Example 20, catalyst Z-1-C1 obtained in Comparative Example 1, and catalyst Z-1-C3 obtained in Comparative Example 3;

[0054] Figure 10 Graph of long-term performance evaluation results of the catalyst in Example 18. Detailed implementation mode

[0055] The present invention will be described in detail below with reference to the examples, but the examples do not limit the protection scope of the present invention.

[0056] In the present invention, the specific surface area, pore volume, and pore diameter were measured on a Tristar-3000 automatic sorptometer produced by Micromeritics, USA. The sample was degassed under vacuum at 350°C for 2 h, and then the specific surface area of the sample was measured by the nitrogen adsorption volumetric method in liquid nitrogen (-196°C), and the result was calculated according to the BET method. The pore diameter and pore volume were calculated by the BJH formula.

[0057] In the present invention, XRD testing was performed using a D8 Advance type polycrystalline powder diffractometer produced by Bruker, Germany, with CuK as the radiation source, the tube voltage was 40 kV, the tube current was 40 mA, the scanning range 2θ was 5° to 85°, and the step size was 0.02°.

[0058] In the present invention, in the characterization means of the binderless catalyst, XRD is used to test the contained phases and the content of each phase, and scanning electron microscopy is used to observe the situation of binder crystal transformation and the morphology of the generated molecular sieve. In the present invention, when the binder used in the preparation of the catalyst is silica sol, then the prepared binderless catalyst does not contain amorphous silica.

[0059] In the present invention, the surface morphology analysis of the catalyst is mainly completed by scanning electron microscopy (SEM). The instrument used for SEM testing is the Nova NanoSEM 450 instrument of FEI Company, USA.

[0060] In the present invention, the silicon-aluminum ratio elemental analysis is determined by X-ray fluorescence spectrometer (XRF). The instrument used is the S4 Pioneer type analyzer of Bruker Company, Germany. The sample is prepared by the tablet pressing method.

[0061] In the present invention, 27 Al NMR is determined by the VNMR 400 instrument of Agilent Company. The signals of framework aluminum and non-framework aluminum species in the sample can be obtained through the small plate chamfering single pulse solid state nuclear magnetic aluminum spectrum. Among them, the spectral peak near 55 ppm is framework aluminum, and the spectral peaks at other high-field chemical shifts are non-framework aluminum. By peak deconvolution fitting integration calculation, the proportion composition of the two is obtained.

[0062] In the present invention, the strength is determined by the DLIII type intelligent particle strength tester of Dalian Penghui Technology Development Co., Ltd.

[0063] In the present invention, NH3 is used as the probe molecule to determine the surface acidity of the catalyst. The experimental conditions of ammonia temperature-programmed desorption (NH3-TPD) are as follows: Take 150 mg of fresh catalyst (screened to 20-40 mesh), load it into a U-shaped quartz tube padded with quartz wool, and in a He atmosphere, heat the catalyst from room temperature to 550 °C at a heating rate of 10 °C / min, and then purge for 1 h. Cool down to room temperature, introduce an ammonia-helium mixed gas containing 10 vol.% NH3, adsorb for 30 min, and then switch to He carrier gas and purge at 100 °C for 1 h until the baseline is flat. Finally, perform temperature-programmed desorption from 100 °C to 620 °C at a heating rate of 10 °C / min. The desorbed ammonia molecules are detected by a TCD detector. The total acid amount is calibrated by ammonia with a standard content. The total acid amount is the sum of the medium-strong acid amount and the strong acid amount. Among them, the medium-strong acid refers to the acid with a desorption temperature < 330 °C, and the strong acid refers to the acid with a desorption temperature of 330-620 °C.

[0064] In the examples and comparative examples of the present invention, the evaluation conditions of the catalyst are as follows: The catalyst is crushed and screened into 20-40 mesh particles. After-ether mixed C4 (mass fraction of n-butene is 71%, mass fraction of isobutene is 1%, and the rest are butane and a small amount of propane and propylene) is used as the raw material. Under the conditions of a temperature of 330 °C, a reaction pressure of 0.12 MPa, a C4 mass space velocity of 3.0 h -1 and a catalyst loading of 5 g, an adiabatic fixed-bed reactor is used to evaluate the catalyst activity.

[0065] In the present invention, the calculation formula for the isobutene yield is as follows:

[0066] Mass yield of isobutene (wt%) = (mass of isobutene in the product - mass of isobutene in the raw material) / mass of n-butene in the raw material × 100%.

[0067] Example 1

[0068] Weigh fumed silica, sodium aluminate, kaolin, binder precursor silica sol (mass concentration of SiO2 is 40%), sodium carbonate, and sesbania powder and mix them (wherein, fumed silica is calculated as SiO2, sodium aluminate and kaolin are calculated as Al2O3, sodium carbonate is calculated as Na2O, and the molar ratio of sodium aluminate, kaolin, sodium carbonate, and fumed silica is 1Al2O3:0.7Na2O:15SiO2, and the molar ratio of sodium aluminate and kaolin calculated as Al2O3 is 1:1; the addition amount of silica sol calculated as SiO2 accounts for 55% of the total mass of fumed silica calculated as SiO2 and sodium aluminate and kaolin calculated as Al2O3, and the addition amount of sesbania powder accounts for 2% of the total mass of fumed silica calculated as SiO2 and sodium aluminate and kaolin calculated as Al2O3). After extrusion molding, cut into pellets, and then dry at 110 °C for 24 h and calcine at 550 °C for 6 h to obtain a precursor. The precursor is mixed with an aqueous solution dissolved with sodium hydroxide and cyclohexylamine (C6H 13 N) (mass concentration of sodium hydroxide is 2.2%, mass concentration of cyclohexylamine is 8.5%) (wherein, the addition amount of cyclohexylamine in moles is as follows: 1Al2O3:1.5C6H 13 N, and the addition amount of sodium hydroxide calculated as Na2O in moles is as follows: 1Al2O3:0.45Na2O). Then, transfer the above mixture to a hydrothermal synthesis reactor and carry out gradient temperature rising crystallization, that is, crystallize at 110 °C, 120 °C, 130 °C, 140 °C, 150 °C, and 160 °C for 24 h respectively. Then wash with distilled water, dry at 110 °C for 24 h and calcine at 550 °C for 6 h to obtain a binderless ZSM-35 molecular sieve catalyst intermediate. Take 2 kg of the catalyst intermediate and add it to 10 L of 10 wt% ammonium nitrate aqueous solution, and stir at 80 °C for 2 h. Repeat the above steps three times. After filtration and washing with distilled water, dry at 110 °C for 24 h and calcine at 550 °C for 6 h to obtain a binderless hydrogen-type ZSM-35 catalyst intermediate, denoted as Z-1.

[0069] The XRD pattern of catalyst intermediate Z-1 is shown in Figure 1 , which has obvious characteristic peaks of ZSM-35. The mass content of ZSM-35 molecular sieve in catalyst intermediate Z-1 is 97%.

[0070] The SEM photograph of catalyst intermediate Z-1 is shown in Figure 2 , and it can be seen from Figure 2 that there is basically no amorphous binder species in catalyst intermediate Z-1.

[0071] Acidity test of catalyst intermediate Z-1: The results are shown in Figure 3 and Table 3.

[0072] The performance evaluation results of catalyst intermediate Z-1 are shown in Table 5.

[0073] Example 2

[0074] Weigh silica, aluminum sulfate, kaolin, binder precursor silica sol (mass concentration of SiO2 is 40%), potassium carbonate, and sesbania powder and mix them (wherein, silica is calculated as SiO2, aluminum sulfate and kaolin are calculated as Al2O3, potassium carbonate is calculated as K2O, and the molar ratio of aluminum sulfate, kaolin, potassium carbonate, and silica is 1Al2O3: 0.7K2O: 15SiO2, and the molar ratio of aluminum sulfate and kaolin calculated as Al2O3 is 1:1; the addition amount of silica sol calculated as SiO2 accounts for 55% of the total mass of silica calculated as SiO2 and aluminum sulfate and kaolin calculated as Al2O3, and the addition amount of sesbania powder accounts for 2% of the total mass of silica calculated as SiO2 and aluminum sulfate and kaolin calculated as Al2O3). After extrusion molding, cut into pellets, and then dry at 100 °C for 24 h and calcine at 500 °C for 6 h to obtain a precursor. The precursor is mixed with an aqueous solution dissolved with potassium hydroxide and n-butylamine (C4H 11 N) (mass concentration of potassium hydroxide is 3%, and mass concentration of n-butylamine is 6.5%) (wherein, the addition amount of n-butylamine in terms of moles is as follows: 1Al2O3: 1.5C4H 11 N, and the addition amount of potassium hydroxide calculated as K2O in terms of moles is as follows: 1Al2O3: 0.45K2O), and then transfer the above mixture to a hydrothermal synthesis reactor for gradient temperature crystallization, that is, crystallize at 110 °C, 130 °C, 150 °C, 160 °C, and 170 °C for 24 h respectively in steps. Then wash with distilled water, dry at 100 °C for 24 h and calcine at 500 °C for 6 h to obtain a binder-free ZSM-35 molecular sieve catalyst intermediate. Take 2 kg of the catalyst intermediate and add it to 15 L of 8 wt% ammonium sulfate aqueous solution for NH4 +Ion exchange was carried out with stirring at 70 °C for 3 h. The above steps were repeated three times. After filtration and washing with distilled water, it was dried at 120 °C for 18 h and calcined at 600 °C for 4 h to obtain a binder-free hydrogen form ZSM-35 catalyst intermediate, denoted as Z-2.

[0075] The XRD pattern of the catalyst intermediate Z-2 is shown in Figure 1 , with obvious characteristic peaks of ZSM-35. The mass content of ZSM-35 zeolite in the catalyst intermediate Z-2 is 97%.

[0076] The SEM photograph of the catalyst intermediate Z-2 is shown in Figure 3 , from Figure 3 it can be seen that there is basically no amorphous binder species in the catalyst intermediate Z-2.

[0077] The acid test results of the catalyst intermediate Z-2 are shown in Figure 8 and Table 3.

[0078] The performance evaluation results of the catalyst intermediate Z-2 are shown in Table 5.

[0079] Example 3

[0080] Weigh silica, pseudoboehmite, kaolin, binder precursor silica sol (SiO2 mass concentration is 40%), sodium carbonate, and methyl cellulose and mix them (wherein, silica is calculated as SiO2, pseudoboehmite and kaolin are calculated as Al2O3, sodium carbonate is calculated as Na2O, and the molar ratio of pseudoboehmite and kaolin, sodium carbonate, and silica is 1Al2O3: 0.7Na2O: 15SiO2, and the molar ratio of pseudoboehmite and kaolin calculated as Al2O3 is 1:1; the addition amount of silica sol calculated as SiO2 accounts for 55% of the total mass of silica calculated as SiO2 and pseudoboehmite and kaolin calculated as Al2O3, and the addition amount of methyl cellulose accounts for 2% of the total mass of silica calculated as SiO2 and pseudoboehmite and kaolin calculated as Al2O3), extrude and form into pellets, and then dry at 110 °C for 24 h and calcine at 550 °C for 6 h to obtain a precursor. The precursor is mixed with an aqueous solution dissolved with sodium hydroxide and 1,4-cyclohexanediamine (C6H 14 N2) (the mass concentration of sodium hydroxide is 2.2%, and the mass concentration of 1,4-cyclohexanediamine is 5.5%) (wherein, the addition amount of 1,4-cyclohexanediamine in moles is as follows: 1Al2O3: 0.83C6H 14For N2, the addition amount of sodium hydroxide in terms of Na2O is as follows in moles: 1 Al2O3: 0.45 Na2O). Then, the above mixture is transferred to a hydrothermal synthesis autoclave and crystallized by gradient heating, that is, crystallized at 100 °C, 120 °C, 140 °C, 160 °C, and 170 °C for 24 h respectively in steps. Then it is washed with distilled water and dried at 110 °C for 24 h and calcined at 550 °C for 6 h to obtain a binder-free sodium-type ZSM-35 molecular sieve catalyst intermediate. Take 2 kg of the catalyst intermediate and add it to 10 L of an ammonium acetate aqueous solution with a concentration of 10 wt%, and perform NH4 + ion exchange and stir at 50 °C for 4 h. Repeat the above steps three times. After filtration and washing with distilled water, it is dried at 110 °C for 24 h and calcined at 550 °C for 6 h to obtain a binder-free hydrogen-type ZSM-35 catalyst intermediate, denoted as Z-3.

[0081] The XRD pattern of the catalyst intermediate Z-3 is shown in Figure 1 and has obvious ZSM-35 characteristic peaks. The mass content of ZSM-35 molecular sieve in the catalyst intermediate Z-3 is 98%.

[0082] The SEM photograph of the catalyst intermediate Z-3 is shown in Figure 4 and it can be seen from Figure 4 that there is basically no amorphous binder species in the catalyst intermediate Z-3.

[0083] The acid test results of the catalyst intermediate Z-3 are shown in Figure 8 and Table 3.

[0084] The performance evaluation results of the catalyst intermediate Z-3 are shown in Table 5.

[0085] Example 4

[0086] Weigh silica white, sodium aluminate, kaolin, binder precursor silica sol (SiO₂ mass concentration is 40%), sodium carbonate, and microcrystalline cellulose and mix them (wherein, silica white is calculated as SiO₂, sodium aluminate and kaolin are calculated as Al₂O₃, sodium carbonate is calculated as Na₂O, and the molar ratio of sodium aluminate and kaolin, sodium carbonate, and silica white is 1Al₂O₃: 0.7Na₂O: 15SiO₂, and the molar ratio of sodium aluminate and kaolin calculated as Al₂O₃ is 1:1; the addition amount of silica sol calculated as SiO₂ accounts for 52% of the total mass of silica white calculated as SiO₂ and sodium aluminate and kaolin calculated as Al₂O₃, and the addition amount of microcrystalline cellulose accounts for 2.5% of the total mass of silica white calculated as SiO₂ and sodium aluminate and kaolin calculated as Al₂O₃). After extrusion molding, cut into pellets, then dry at 110 °C for 24 h and calcine at 550 °C for 6 h to obtain a precursor. Mix the precursor with an aqueous solution dissolved with sodium hydroxide and ethylenediamine (C₂H₈N₂) (the mass concentration of sodium hydroxide is 2.2%, and the mass concentration of ethylenediamine is 10%) (wherein, the addition amount of ethylenediamine in moles is as follows: 1Al₂O₃: 2.9C₂H₈N₂, and the addition amount of sodium hydroxide calculated as Na₂O in moles is as follows: 1Al₂O₃: 0.45Na₂O), then transfer the above mixture to a hydrothermal synthesis reactor, and carry out gradient temperature rising crystallization, that is, crystallize at 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C, 160 °C, and 170 °C for 20 h respectively in steps. Then wash with distilled water, dry at 110 °C for 24 h and calcine at 550 °C for 6 h to obtain a binder-free sodium form ZSM-35 molecular sieve catalyst intermediate. Take 2 kg of the catalyst intermediate, add it to 10 L of a 15 wt% ammonium nitrate aqueous solution, and carry out NH₄ + ion exchange, and stir at 80 °C for 2 h. Repeat the above steps three times. After filtration and washing with distilled water, dry at 110 °C for 24 h and calcine at 550 °C for 6 h to obtain a binder-free hydrogen form ZSM-35 catalyst intermediate, denoted as Z-4.

[0087] The XRD pattern of the catalyst intermediate Z-4 is shown in Figure 1 , which has obvious ZSM-35 characteristic peaks, and the mass content of ZSM-35 molecular sieve in the catalyst intermediate Z-4 is 96%.

[0088] The SEM photograph of the catalyst intermediate Z-4 is shown in Figure 5 , and it can be seen from Figure 5 that there is basically no amorphous binder species in the catalyst intermediate Z-4.

[0089] The acidic test results of the catalyst intermediate Z-4 are shown in Figure 8 and Table 3.

[0090] The performance evaluation results of the catalyst intermediate Z-4 are shown in Table 5.

[0091] Example 5

[0092] Weigh and mix silica white, sodium aluminate, pseudo-boehmite, binder precursor silica sol (SiO₂ mass concentration is 40%), sodium carbonate, and sesbania powder (wherein, silica white is calculated as SiO₂, sodium aluminate and pseudo-boehmite are calculated as Al₂O₃, sodium carbonate is calculated as Na₂O, and the molar ratio of sodium aluminate, pseudo-boehmite, sodium carbonate, and silica white is 1Al₂O₃: 0.7Na₂O: 15SiO₂, and the molar ratio of sodium aluminate and pseudo-boehmite calculated as Al₂O₃ is 1:1; the addition amount of silica sol calculated as SiO₂ accounts for 50% of the total mass of silica white calculated as SiO₂ and sodium aluminate and pseudo-boehmite calculated as Al₂O₃, and the addition amount of sesbania powder accounts for 2.5% of the total mass of silica white calculated as SiO₂ and sodium aluminate and pseudo-boehmite calculated as Al₂O₃). After extrusion molding, cut into pellets, and then dry at 110 °C for 24 h and calcine at 550 °C for 6 h to obtain a precursor mixture. The precursor mixture is mixed with an aqueous solution containing sodium hydroxide and cyclohexylamine (C₆H 13 N) (the mass concentration of sodium hydroxide is 1.8%, and the mass concentration of cyclohexylamine is 8.5%) (wherein, the addition amount of cyclohexylamine in moles is as follows: 1Al₂O₃: 1.5C₆H 13 N, and the addition amount of sodium hydroxide calculated as Na₂O in moles is as follows: 1Al₂O₃: 0.40Na₂O). Then transfer the above mixture to a hydrothermal synthesis reactor and carry out gradient temperature rise crystallization, that is, crystallize at 120 °C, 130 °C, 140 °C, 150 °C, and 160 °C for 24 h respectively. Then wash with distilled water, dry at 110 °C for 24 h and calcine at 550 °C for 6 h to obtain a binder-free sodium-type ZSM-35 molecular sieve catalyst intermediate. Take 2 kg of the catalyst intermediate and add it to 10 L of a 15 wt% ammonium acetate aqueous solution, and stir at 40 °C for 2 h. Repeat the above steps three times. After filtration and washing with distilled water, dry at 110 °C for 24 h and calcine at 550 °C for 6 h to obtain a binder-free hydrogen-type ZSM-35 catalyst intermediate, denoted as Z-5.

[0093] The XRD pattern of the catalyst intermediate Z-5 is shown in Figure 1 , which has obvious ZSM-35 characteristic peaks, and the mass content of ZSM-35 molecular sieve in the catalyst intermediate Z-5 is 96%.

[0094] The SEM photograph of the catalyst intermediate Z-5 is shown in Figure 6 , and it can be seen from Figure 6 that there are basically no amorphous binder species in the catalyst intermediate Z-5.

[0095] The acid test results of the catalyst intermediate Z-5 are shown in Figure 8 and Table 3.

[0096] The performance evaluation results of catalyst intermediate Z-5 are shown in Table 5.

[0097] Example 6

[0098] Weigh and mix fumed silica, sodium aluminate, kaolin, binder precursor silica sol (SiO2 mass concentration is 40%), sodium carbonate, and methyl cellulose (wherein, fumed silica is calculated as SiO2, sodium aluminate and kaolin are calculated as Al2O3, sodium carbonate is calculated as Na2O, the molar ratio of sodium aluminate, kaolin, sodium carbonate, and fumed silica is 1Al2O3: 0.7Na2O: 15SiO2, and the molar ratio of sodium aluminate and kaolin calculated as Al2O3 is 1:1; the addition amount of silica sol calculated as SiO2 accounts for 50% of the total mass of fumed silica calculated as SiO2 and sodium aluminate and kaolin calculated as Al2O3, and the addition amount of sesbania powder accounts for 2.5% of the total mass of fumed silica calculated as SiO2 and sodium aluminate and kaolin calculated as Al2O3). After extrusion molding, cut into pellets, and then dry at 110 °C for 24 h and calcine at 550 °C for 6 h to obtain the precursor. The precursor is mixed with an aqueous solution containing sodium hydroxide and n-butylamine (C4H 11 N) (the mass concentration of sodium hydroxide is 1.8%, and the mass concentration of n-butylamine is 6.5%) (wherein, the addition amount of n-butylamine in moles is as follows: 1Al2O3: 1.5C4H 11 N, and the addition amount of sodium hydroxide calculated as Na2O in moles is as follows: 1Al2O3: 0.40Na2O). Then transfer the above mixture to a hydrothermal synthesis reactor and crystallize at a gradient temperature, that is, crystallize at 110 °C, 125 °C, 140 °C, 155 °C, 170 °C, and 185 °C for 24 h respectively. Then wash with distilled water, dry at 110 °C for 24 h and calcine at 550 °C for 6 h to obtain a binder-free sodium-type ZSM-35 molecular sieve catalyst intermediate. Take 2 kg of the catalyst intermediate and add it to 10 L of a 15 wt% aqueous ammonium sulfate solution, and stir at 80 °C for 2 h. Repeat the above steps three times. After filtration and washing with distilled water, dry at 110 °C for 24 h and calcine at 550 °C for 6 h to obtain a binder-free hydrogen-type ZSM-35 catalyst intermediate, denoted as Z-6.

[0099] The XRD pattern of catalyst intermediate Z-6 is shown in Figure 1 , which has obvious ZSM-35 characteristic peaks, and the mass content of ZSM-35 molecular sieve in catalyst intermediate Z-6 is 97%.

[0100] The SEM photograph of catalyst intermediate Z-6 is shown in Figure 7 , from Figure 7 it can be seen that there is basically no amorphous binder species in catalyst intermediate Z-6.

[0101] The acid test results of catalyst intermediate Z-6 are shown in Figure 8 and Table 3.

[0102] The performance evaluation results of catalyst intermediate Z-6 are shown in Table 4.

[0103] Example 7

[0104] Take 400 g of catalyst intermediate Z-1 and place it in a rotary tube furnace. Under the conditions of a rotation speed of 5 rpm, a pressure of 0.3 MPa, a temperature of 450 °C, and a steam mass space velocity of 1.5 h -1 , carry out steam treatment on the catalyst for 8 h, stop heating, switch to nitrogen, purge and cool down to obtain the catalyst, denoted as Z-1-7.

[0105] The acid test results of catalyst Z-1-7 are shown in Figure 9 and Table 3.

[0106] The performance evaluation results of catalyst Z-1-7 are shown in Table 5.

[0107] Example 8

[0108] Take 400 g of catalyst intermediate Z-1 and place it in a rotary tube furnace. Under the conditions of a rotation speed of 5 rpm, a pressure of 0.2 MPa, a temperature of 475 °C, and a steam mass space velocity of 1.5 h -1 , carry out steam treatment on the catalyst for 6.5 h, stop heating, switch to nitrogen, purge and cool down to obtain the catalyst, denoted as Z-1-8.

[0109] The acid test results of catalyst Z-1-8 are shown in Table 3.

[0110] The performance evaluation results of catalyst Z-1-8 are shown in Table 5.

[0111] Example 9

[0112] Take 400 g of catalyst intermediate Z-1 and place it in a rotary tube furnace. Under the conditions of a rotation speed of 4 rpm, a pressure of 0.2 MPa, a temperature of 500 °C, and a steam mass space velocity of 1.5 h -1 , carry out steam treatment on the catalyst for 5.0 h, stop heating, switch to nitrogen, purge and cool down to obtain the catalyst, denoted as Z-1-9.

[0113] The acid test results of catalyst Z-1-9 are shown in Table 3.

[0114] The performance evaluation results of catalyst Z-1-9 are shown in Table 5.

[0115] Example 10

[0116] Take 400 g of catalyst intermediate Z-1 and place it in a rotary tube furnace. Under the conditions of a rotation speed of 3 rpm, a pressure of 0.1 MPa, a temperature of 525 °C, and a steam mass space velocity of 1.5 h -1Under the condition of [condition], the catalyst was treated with steam for 4.0 h, the heating was stopped, the gas was switched to nitrogen, and the catalyst was purged and cooled to obtain the catalyst, denoted as Z-1-10.

[0117] The acid test results of catalyst Z-1-10 are shown in Table 3.

[0118] The performance evaluation results of catalyst Z-1-10 are shown in Table 5.

[0119] Example 11

[0120] Take 400 g of catalyst intermediate Z-1 and place it in a rotary tube furnace. Under the conditions of a rotation speed of 3 rpm, a pressure of 0.1 MPa, a temperature of 550 °C, and a steam mass hourly space velocity of 1.5 h -1 The catalyst was treated with steam for 3.5 h, the heating was stopped, the gas was switched to nitrogen, and the catalyst was purged and cooled to obtain the catalyst, denoted as Z-1-11.

[0121] The acid test results of catalyst Z-1-11 are shown in Table 3.

[0122] The performance evaluation results of catalyst Z-1-11 are shown in Table 5.

[0123] Example 12

[0124] Take 400 g of catalyst intermediate Z-1 and place it in a rotary tube furnace. Under the conditions of a rotation speed of 2 rpm, atmospheric pressure, a temperature of 575 °C, and a steam mass hourly space velocity of 1.5 h -1 The catalyst was treated with steam for 3.0 h, the heating was stopped, the gas was switched to nitrogen, and the catalyst was purged and cooled to obtain the catalyst, denoted as Z-1-12.

[0125] The acid test results of catalyst Z-1-12 are shown in Figure 9 and Table 3.

[0126] The performance evaluation results of catalyst Z-1-12 are shown in Table 5.

[0127] Example 13

[0128] Take 400 g of catalyst intermediate Z-1 and place it in a rotary tube furnace. Under the conditions of a rotation speed of 2 rpm, atmospheric pressure, a temperature of 600 °C, and a steam mass hourly space velocity of 1.5 h -1 The catalyst was treated with steam for 2.5 h, the heating was stopped, the gas was switched to nitrogen, and the catalyst was purged and cooled to obtain the catalyst, denoted as Z-1-13.

[0129] The acid test results of catalyst Z-1-13 are shown in Table 3.

[0130] The performance evaluation results of catalyst Z-1-13 are shown in Table 5.

[0131] Example 14

[0132] Take 400 g of catalyst intermediate Z-1 and place it in a rotary tube furnace. Under the conditions of a rotation speed of 2 rpm, atmospheric pressure, a temperature of 625 °C, and a steam mass space velocity of 1.5 h -1 , carry out steam treatment on the catalyst for 2.0 h. Stop heating, switch to nitrogen, purge and cool down to obtain the catalyst, denoted as Z-1-14.

[0133] The acid test results of catalyst Z-1-14 are shown in Table 3.

[0134] The performance evaluation results of catalyst Z-1-14 are shown in Table 5.

[0135] Example 15

[0136] Take 400 g of catalyst intermediate Z-2 and place it in a rotary tube furnace. Under the conditions of a rotation speed of 1 rpm, a pressure of 0.1 MPa, a temperature of 515 °C, and a steam mass space velocity of 0.5 h -1 , carry out steam treatment on the catalyst for 4.0 h. Stop heating, switch to nitrogen, purge and cool down to obtain the catalyst, denoted as Z-2-15.

[0137] The acid test results of catalyst Z-2-15 are shown in Table 3.

[0138] The performance evaluation results of catalyst Z-2-15 are shown in Table 5.

[0139] Example 16

[0140] Take 400 g of catalyst intermediate Z-2 and place it in a rotary tube furnace. Under the conditions of a rotation speed of 1 rpm, a pressure of 0.1 MPa, a temperature of 515 °C, and a steam mass space velocity of 0.6 h -1 , carry out steam treatment on the catalyst for 4.0 h. Stop heating, switch to nitrogen, purge and cool down to obtain the catalyst, denoted as Z-2-16.

[0141] The acid test results of catalyst Z-2-16 are shown in Table 3.

[0142] The performance evaluation results of catalyst Z-2-16 are shown in Table 5.

[0143] Example 17

[0144] Take 400 g of catalyst intermediate Z-2 and place it in a rotary tube furnace. Under the conditions of a rotation speed of 1 rpm, a pressure of 0.1 MPa, a temperature of 515 °C, and a steam mass space velocity of 1.0 h -1 , carry out steam treatment on the catalyst for 4.0 h. Stop heating, switch to nitrogen, purge and cool down to obtain the catalyst, denoted as Z-2-17.

[0145] The acid test results of catalyst Z-2-17 are shown in Table 3.

[0146] The performance evaluation results of catalyst Z-2-17 are shown in Table 5.

[0147] Example 18

[0148] Take 400 g of catalyst intermediate Z-2 and place it in a rotary tube furnace. Under the conditions of a rotation speed of 1 rpm, a pressure of 0.1 MPa, a temperature of 515 °C, and a steam mass space velocity of 1.2 h -1 , carry out steam treatment on the catalyst for 4.0 h, stop heating, switch to nitrogen, purge and cool down to obtain the catalyst, denoted as Z-2-18.

[0149] The acid test results of catalyst Z-2-18 are shown in Table 3.

[0150] The performance evaluation results of catalyst Z-2-18 are shown in Table 5.

[0151] The long-term performance evaluation of catalyst Z-2-18 was carried out, and the results are shown in Figure 10 . It can be seen from Figure 10 that: at a reaction temperature of 330-345 °C, the catalyst runs stably for more than 56 d, and the average single-pass yield of isobutene is 39.2%. It can be seen that the catalyst of the present invention has good stability.

[0152] Example 19

[0153] Take 400 g of catalyst intermediate Z-2 and place it in a rotary tube furnace. Under the conditions of a rotation speed of 1 rpm, a pressure of 0.1 MPa, a temperature of 515 °C, and a steam mass space velocity of 1.5 h -1 , carry out steam treatment on the catalyst for 4.0 h, stop heating, switch to nitrogen, purge and cool down to obtain the catalyst, denoted as Z-2-19.

[0154] The acid test results of catalyst Z-2-19 are shown in Table 3.

[0155] The performance evaluation results of catalyst Z-2-19 are shown in Table 5.

[0156] Example 20

[0157] Take 400 g of catalyst intermediate Z-2 and place it in a rotary tube furnace. Under the conditions of a rotation speed of 1 rpm, a pressure of 0.1 MPa, a temperature of 515 °C, and a steam mass space velocity of 2.3 h -1 , carry out steam treatment on the catalyst for 4.0 h, stop heating, switch to nitrogen, purge and cool down to obtain the catalyst, denoted as Z-2-20.

[0158] The acid test results of catalyst Z-2-20 are shown in Figure 9 and Table 3.

[0159] The performance evaluation results of catalyst Z-2-20 are shown in Table 5.

[0160] Example 21

[0161] Take 400 g of catalyst intermediate Z-2 and place it in a rotary tube furnace. Under the conditions of a rotation speed of 1 rpm, a pressure of 0.1 MPa, a temperature of 515 °C, and a steam mass hourly space velocity of 3.0 h -1 Perform steam treatment on the catalyst for 4.0 h. Stop heating, switch to nitrogen, purge and cool down to obtain the catalyst, denoted as Z-2-21.

[0162] The acid test results of catalyst Z-2-21 are shown in Table 3.

[0163] The performance evaluation results of catalyst Z-2-21 are shown in Table 5.

[0164] Example 22

[0165] Take 400 g of catalyst intermediate Z-3 and place it in a rotary tube furnace. Under the conditions of a rotation speed of 2 rpm, atmospheric pressure, a temperature of 520 °C, and a steam mass hourly space velocity of 1.0 h -1 Perform steam treatment on the catalyst for 4.0 h. Stop heating, switch to nitrogen, purge and cool down to obtain the catalyst, denoted as Z-3-22.

[0166] The acid test results of catalyst Z-3-22 are shown in Table 3.

[0167] The performance evaluation results of catalyst Z-3-22 are shown in Table 5.

[0168] Example 23

[0169] Take 400 g of catalyst intermediate Z-4 and place it in a rotary tube furnace. Under the conditions of a rotation speed of 1 rpm, a pressure of 0.05 MPa, a temperature of 530 °C, and a steam mass hourly space velocity of 1.2 h -1 Perform steam treatment on the catalyst for 4.0 h. Stop heating, switch to nitrogen, purge and cool down to obtain the catalyst, denoted as Z-4-23.

[0170] The acid test results of catalyst Z-4-23 are shown in Table 3.

[0171] The performance evaluation results of catalyst Z-4-23 are shown in Table 5.

[0172] Example 24

[0173] Take 400 g of catalyst intermediate Z-5 and place it in a rotary tube furnace. Under the conditions of a rotation speed of 1 rpm, atmospheric pressure, a temperature of 580 °C, and a steam mass hourly space velocity of 2.0 h -1Under the condition of [specific condition], the catalyst was treated with steam for 3.0 h, the heating was stopped, nitrogen was switched on, and the catalyst was purged and cooled to obtain the catalyst, denoted as Z-5-24.

[0174] The acid test results of catalyst Z-5-24 are shown in Table 3.

[0175] The performance evaluation results of catalyst Z-5-24 are shown in Table 5.

[0176] Example 25

[0177] Take 400 g of catalyst intermediate Z-6 and place it in a rotary tube furnace. Under the conditions of a rotation speed of 2 rpm, a pressure of 0.1 MPa, a temperature of 500 °C, and a steam mass hourly space velocity of 1.0 h -1 the catalyst was treated with steam for 5.0 h, the heating was stopped, nitrogen was switched on, and the catalyst was purged and cooled to obtain the catalyst, denoted as Z-6-25.

[0178] The acid test results of catalyst Z-6-25 are shown in Table 3.

[0179] The performance evaluation results of catalyst Z-6-25 are shown in Table 5.

[0180] Comparative Example 1

[0181] Take 400 g of catalyst intermediate Z-1 and place it in a rotary tube furnace. Under the conditions of a rotation speed of 2 rpm, atmospheric pressure, a temperature of 575 °C, and a steam mass hourly space velocity of 0, the catalyst was treated with steam for 3.0 h, the heating was stopped, nitrogen was switched on, and the catalyst was purged and cooled to obtain the catalyst, denoted as Z-1-C1.

[0182] The acid test results of catalyst Z-1-C1 are shown in Figure 9 and Table 3.

[0183] The performance evaluation results of catalyst Z-1-C1 are shown in Table 5.

[0184] Comparative Example 2

[0185] Take 400 g of catalyst intermediate Z-2 and place it in a rotary tube furnace. Under the conditions of a rotation speed of 0, a pressure of 0.1 MPa, a temperature of 515 °C, and a steam mass hourly space velocity of 0.5 h -1 the catalyst was treated with steam for 4.0 h, the heating was stopped, nitrogen was switched on, and the catalyst was purged and cooled to obtain the catalyst, denoted as Z-2-C2.

[0186] The acid test results of catalyst Z-2-C2 are shown in Table 3.

[0187] The performance evaluation results of catalyst Z-2-C2 are shown in Table 5.

[0188] Comparative Example 3

[0189] Take 400 g of catalyst intermediate Z-1 and place it in a rotary tube furnace. Under the conditions of a rotation speed of 2 rpm, atmospheric pressure, a temperature of 350 °C, and a steam mass space velocity of 1.5 h -1 , carry out steam treatment on the catalyst for 3.0 h, stop heating, switch to nitrogen, purge and cool down to obtain the catalyst, denoted as Z-1-C3.

[0190] The acid test results of catalyst Z-1-C3 are shown in Figure 9 and Table 3.

[0191] The performance evaluation results of catalyst Z-1-C3 are shown in Table 5.

[0192] Comparative Example 4

[0193] Take 400 g of catalyst Z-2 and place it in a rotary tube furnace. Under the conditions of a rotation speed of 1 rpm, a pressure of 0.1 MPa, a temperature of 515 °C, and a steam mass space velocity of 0.20 h -1 , carry out steam treatment on the catalyst for 4.0 h, stop heating, switch to nitrogen, purge and cool down to obtain the catalyst, denoted as Z-2-C4.

[0194] The acid test results of catalyst Z-2-C4 are shown in Table 3.

[0195] The performance evaluation results of catalyst Z-2-C4 are shown in Table 5.

[0196] Table 1 Properties of the catalysts obtained in each example

[0197]

[0198]

[0199] Table 2 Radial crushing strength of the catalysts obtained in each example

[0200]

[0201]

[0202] Table 3 Acid properties of the catalysts obtained in each example

[0203]

[0204]

[0205] Table 4 Composition of framework aluminum and non-framework aluminum in the structures of the catalysts obtained in each example

[0206]

[0207]

[0208] Activity evaluation results of the catalysts obtained in each example in Table 5

[0209]

[0210]

[0211] As can be seen from Table 5, the catalyst of the present invention can be used in the skeletal isomerization reaction of C4 olefins to improve the isobutene yield, and at the same time, the stability of the catalyst is significantly enhanced.

Claims

1. A binderless ZSM-35 molecular sieve catalyst, characterized in that, Based on the weight of aluminum in the catalyst, the content of framework aluminum is 58% - 82%, and the content of non-framework aluminum is 18% - 42%. The total acid amount of the catalyst is 0.40 - 0.70 mmol·g -1 ; the total acid amount is the sum of the medium-strong acid amount and the strong acid amount, wherein the medium-strong acid content accounts for 55% - 75%, and the strong acid content accounts for 25% - 45%; The acid amount is determined by ammonia temperature-programmed desorption method. Medium-strong acids refer to acids with desorption temperature ≥ 100°C and < 330°C, and strong acids refer to acids with desorption temperature of 330 - 620°C.

2. The catalyst according to claim 1, characterized in that, Based on the weight of aluminum in the catalyst, the content of framework aluminum is 65% - 80%, and the content of non-framework aluminum is 20% - 35%.

3. The catalyst according to claim 1, characterized in that, The total acid amount of the catalyst is 0.45 - 0.70 mmol·g -1 ; And / or, in the catalyst, the content of medium-strong acids accounts for 60% - 70%, and the content of strong acids accounts for 30% - 40%.

4. The catalyst according to claim 1, characterized in that, The specific surface area of the catalyst is 250-350 m 2 ·g -1 ; The pore volume is 0.1 - 0.3 cm 3 ·g -1 ; the average pore diameter is 2.0 - 5.0 nm.

5. The catalyst according to claim 4, characterized in that, The specific surface area of the catalyst is 270-320 m 2 ·g -1 .

6. The catalyst according to claim 1, wherein The molar ratio of SiO2 / Al2O3 of the catalyst is 10 - 30.

7. The catalyst according to claim 6, characterized in that, The molar ratio of SiO2 / Al2O3 of the catalyst is 15 - 25.

8. The catalyst according to claim 1, characterized in that, The radial crushing strength of the catalyst is 4-10 N·mm -1 .

9. The catalyst according to claim 8, characterized in that, The radial crushing strength of the catalyst is 5-8 N·mm -1 .

10. The preparation method of the binderless ZSM-35 molecular sieve catalyst according to any one of claims 1 - 9, comprising: a) Mixing a silicon source, an aluminum source, a first alkali source, a binder precursor, and an auxiliary agent, forming, first drying, and first calcining to obtain a precursor; b) Mixing a solution containing a second alkali source and a template agent with the precursor obtained in step a), performing hydrothermal crystallization, second drying, and second calcining to obtain a catalyst intermediate; c) After subjecting the catalyst intermediate obtained in step b) to ammonium exchange, performing steam treatment to obtain a binderless ZSM-35 molecular sieve catalyst; The steam treatment process described in step c) is carried out in a rotary tube furnace; the conditions of the steam treatment described in step c) are as follows: the mass space velocity of steam is 0.3 - 5 h -1 ; the treatment temperature is 400 - 700 °C; the treatment pressure is 0 - 1 MPa; the treatment time is 1 - 10 h.

11. The preparation method according to claim 10, characterized in that, The silicon source in step a) is fumed silica; the aluminum source is one or more of sodium aluminate, aluminum sulfate, kaolin, and pseudoboehmite; the first alkali source is one or more of sodium carbonate and potassium carbonate; the binder is amorphous silica, and the binder precursor is silica sol; The auxiliary agent is one or more of talc powder, cellulose, and starch; And / or, the second alkali source in step b) is one or more of sodium hydroxide and potassium hydroxide; the template agent is one or more of cyclohexylamine, n-butylamine, 1,4-cyclohexanediamine, and ethylenediamine; And / or, in the solution containing the second alkali source and the template agent in step b), the mass concentration of the second alkali source is 1% - 3%, and the mass concentration of the template agent is 3% - 15%.

12. The preparation method according to claim 10, characterized in that, The conditions of the first drying in step a) are as follows: the first drying temperature is 80 - 200°C, and the first drying time is 12 - 48 h. The conditions of the first calcining are as follows: the first calcining temperature is 400 - 600°C, and the first calcining time is 3 - 12 h; And / or, the conditions of the second drying in step b) are as follows: the drying temperature is 80 - 120°C, and the drying time is 12 - 48 h. The conditions of the second calcining are as follows: the calcining temperature is 400 - 600°C, and the calcining time is 3 - 12 h.

13. The preparation method according to claim 10, characterized in that, In step a), a silicon source, an aluminum source, a first alkali source, a binder precursor, and an auxiliary agent are mixed. Herein, the silicon source is calculated as SiO2, the aluminum source is calculated as Al2O3, and the first alkali source is calculated as oxide M2O. The material ratios of the silicon source, aluminum source, and first alkali source are as follows: the molar ratio of SiO2 to Al2O3 is 10 - 20:1, and the molar ratio of M2O to Al2O3 is 0.4 - 1.0:1; the amount of the binder precursor, calculated as the binder, is 40% - 60% of the total mass of the silicon source calculated as SiO2 and the aluminum source calculated as Al2O3, and the amount of the auxiliary agent is 1% - 5% of the total mass of the silicon source calculated as SiO2 and the aluminum source calculated as Al2O3; and / or, in step b), a solution containing a second alkali source and a template agent is mixed with the precursor obtained in step a). In the resulting mixture, the molar ratio of the second alkali source calculated as oxide M2O to the aluminum source calculated as Al2O3 in step a) is 0.30 - 0.6:1; the molar ratio of the template agent to the aluminum source calculated as Al2O3 in step a) is 1 - 6:

1.

14. The preparation method according to claim 10, wherein, The hydrothermal crystallization in step b) is carried out by gradient temperature rising crystallization. The starting temperature is 80 - 140 °C, the ending temperature is 150 - 200 °C, and the total crystallization time is 48 - 192 h; wherein, the gradient temperature rising crystallization uses at least 2 gradients, and the temperature difference between adjacent two gradients is at least 5 °C or more.

15. The preparation method according to claim 14, characterized in that, The gradient temperature rising crystallization in step b) uses 2 - 10 gradients, and the temperature difference between adjacent two gradients is at least 10 °C or more.

16. The preparation method according to claim 14, characterized in that, The gradient temperature rising crystallization in step b) uses 2 - 10 gradients, and the temperature difference between adjacent two gradients is 10 - 30 °C.

17. The preparation method according to claim 10, characterized in that, The steam treatment process in step c) is carried out in a rotary tube furnace, and the rotation speed ≥ 1 rpm.

18. The preparation method according to claim 10, characterized in that, The steam treatment process in step c) is carried out in a rotary tube furnace, and the rotation speed is 1 - 5 rpm.

19. The preparation method according to claim 10, characterized in that, The conditions for the steam treatment described in step c) are as follows: the mass space velocity of steam is 0.5 to 3.0 h -1 ; the treatment temperature is 450 to 600 °C; the treatment pressure is 0 to 0.5 MPa; the treatment time is 3 to 8 h.

20. Application of the catalyst according to any one of claims 1 - 9 or the catalyst prepared by the preparation method according to any one of claims 10 - 19 in the skeletal isomerization reaction of C4 olefins.

21. The application according to claim 20, characterized in that, The C4 olefin is 1-butene or a mixed hydrocarbon containing 1-butene; and / or, the temperature of the reaction is 200 to 500 °C; and / or, the pressure of the reaction is 0 to 1 MPa; and / or, the mass hourly space velocity of the C4 olefin is 0.1 to 10 h -1 .

22. The application according to claim 21, wherein The temperature of the reaction is 300 to 450 °C; and / or, the pressure of the reaction is 0 to 0.5 MPa; and / or, the mass hourly space velocity of the C4 olefins is 0.5 to 6 h -1 .

23. The application according to claim 21, wherein The temperature of the reaction is 300 to 450 °C; and / or, the pressure of the reaction is 0 to 0.2 MPa; and / or, the mass hourly space velocity of the C4 olefins is 0.5 to 6 h -1 .

Images