CN112237942A

CN112237942A - High-zinc-silicon-ratio CHA type topological structure zinc-silicon molecular sieve catalyst, preparation method and application thereof

Info

Publication number: CN112237942A
Application number: CN201910643244.4A
Authority: CN
Inventors: 乔健; 刘松霖; 袁志庆; 张铁柱; 滕加伟
Original assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Current assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Priority date: 2019-07-17
Filing date: 2019-07-17
Publication date: 2021-01-19
Anticipated expiration: 2039-07-17
Also published as: CN112237942B

Abstract

The invention relates to a CHA type topological structure zinc-silicon molecular sieve catalyst with high zinc-silicon ratio, a preparation method and application thereof, and mainly solves the problems that the stability of an olefin catalyst prepared by using methanol is not high, the ethylene and propylene in low-carbon olefin are low, and particularly the selectivity and yield of the propylene are low in the prior art. The invention adopts a CHA type topological structure zinc-silicon molecular sieve catalyst with high zinc-silicon ratio, which is characterized by comprising the following components in parts by weight: a) 10-99 parts of a CHA-type topological structure zinc-silicon molecular sieve with high zinc-silicon ratio; b) the technical scheme of 1-90 parts of the binder well solves the problem and can be used in industrial production of preparing olefin from methanol.

Description

High-zinc-silicon-ratio CHA type topological structure zinc-silicon molecular sieve catalyst, preparation method and application thereof

Technical Field

The invention relates to a CHA type topological structure zinc-silicon molecular sieve catalyst with high zinc-silicon ratio, a preparation method and application thereof.

Background

Early zeolites were aluminosilicates which were made of SiO₄Tetrahedron and AlO₄Tetrahedron is a basic structural unit and is connected by bridge oxygen to form a microporous compound with a cage-shaped or pore canal structure. According to the definition of the International Union of Pure and Applied Chemistry (IUPAC), porous materials can be classified into the following three classes according to their pore diameters: the material with the pore diameter less than 2nm is microporous material; the material with the pore diameter between 2 and 50nm is mesoporous material (mesoporous materials); materials with pore sizes greater than 50nm are macroporous materials (macroporous materials) and zeolite molecular sieve channels are typically below 2nm in diameter and are therefore classified as microporous materials. And due to the wide distribution range of the sizes of the inner cavities and the rich diversity of topological structures, the zeolite molecular sieve material is widely applied to the fields of adsorption, heterogeneous catalysis, carriers of various object molecules, ion exchange and the like. They are mainly characterized by selective adsorption and their unique system of channels gives them the ability to screen molecules of different sizes, which is why this class of materials is called molecular sieves ".

In the last 40 th century, Barrer and others synthesized artificial zeolite which did not exist in nature for the first time in the laboratory, and in the next more than ten years, Milton, Breck and Sand and others synthesized A-type, X-type, L-type and Y-type zeolites, mordenite and the like by adding alkali metal or alkaline earth metal hydroxide to aluminosilicate gel by using a hydrothermal technology; in the sixties of the twentieth century, along with the introduction of organic base cations, a series of zeolite molecular sieves with brand new structures, such as ZSM-n series (ZSM-1, ZSM-5, ZSM-11, ZSM-22, ZSM-48 and the like) zeolite molecular sieves, are prepared, and have the advantages of good catalytic activity, good hydrothermal stability, high corrosion resistance and the like, so that the zeolite molecular sieves are widely applied to the fields of petroleum processing, fine chemical engineering and the like and are the hot spots of research of people for many years.

In 1982, Wilson S.T. and Flanigen E.M. et al, scientists in United states of America, CorpSuccessfully synthesizes and develops a brand new molecular sieve family, namely an aluminum phosphate molecular sieve AlPO by using an aluminum source, a phosphorus source and an organic template₄N, n represents the model number (US 4310440). Two years later, UCC in AlPO₄Based on-n, Si atoms are used for partially replacing Al atoms and P atoms in an AlPO framework, and another series of silicoaluminophosphate molecular sieves SAPO-n are successfully prepared, wherein n represents the type (US4440871, US 4499327). In the structure of SAPO-n, Si atom replaces P or Al atom in original AlPO to form SiO₄、AlO₄And PO₄A non-neutral molecular sieve framework of tetrahedral composition, in which silicon is present in two ways: (1) one Si atom replacing one P atom; (2)2 silicon atoms respectively replace a pair of aluminum atoms and phosphorus atoms, and show certain acidity, oxidability and the like, thereby greatly improving the catalytic activity of the catalyst and having wide application prospect in the field of petrochemical industry

SAPO-34 molecular sieve, an important member of SAPO-n, has a structure similar to chabazite and belongs to the cubic system. The SAPO-34 framework element is formed by AlO₂ ^-、SiO₂And PO₂ ⁺The structure comprises an ellipsoidal super cage and a three-dimensional cross structure of 8-member ring pore channels, wherein the pore diameter of the 8-member ring pore channels is about 0.38nm, the diameter of the orifice of the super cage is kept between 0.43 and 0.50nm, and the topological sign CHA is adopted.

The SAPO-34 molecular sieve has proper protonic acidity, larger specific surface area, better adsorption performance, better thermal stability, good hydrothermal stability, excellent type selection selectivity of a pore structure to low-carbon olefin and the like, so that the SAPO-34 molecular sieve used as a catalyst for preparing the low-carbon olefin (MTO) from the methanol shows good catalytic activity and selectivity, the initial conversion rate can reach 100%, the selectivity of diene (ethylene and propylene) can reach more than 80%, and C is C₅The above products are very small in amount.

The traditional method for preparing SAPO-34 is a hydrothermal crystallization method, (US4440871, CN1037334C, CN1038125C and CN1048428C) is obtained by crystallization in a high-temperature hydrothermal system, namely, after an aluminum source, a silicon source, a phosphorus source, a template agent and water are intensively and uniformly stirred according to a certain reaction ratio to form a crystallization mixed solution, the crystallization is directly performed at a certain temperature. An aluminum source is generally selected from aluminum isopropoxide or pseudo-boehmite, a silicon source is usually acidic silica sol or white carbon black, a phosphorus source is phosphoric acid, a template agent is usually selected from tetraethylammonium hydroxide, triethylamine and morpholine, SAPO-34 grains prepared from the tetraethylammonium hydroxide are generally small and have good catalytic performance, but the template agent is high in cost, and the SAPO-34 molecular sieve grains synthesized from the triethylamine and the morpholine which are low in price are large.

Chinese patent CN1088483 discloses a method for preparing a large-grain SAPO-34 molecular sieve by using an organic template with low price.

Chinese patent CN101525141A discloses a method for preparing small-grain SAPO-34 molecular sieve by using ultrasonic technology, wherein crystallization liquid is pretreated by ultrasonic waves, and the small-grain SAPO-34 molecular sieve is obtained by shorter crystallization time.

Chinese patent CN101293660 provides a method for preparing SAPO-34 molecular sieve by controlling the feeding sequence, but the feeding sequence and the operation process involved in the method are more complicated.

Chinese patent CN101121529 discloses a method for rapidly synthesizing SAPO-34 molecular sieve by using triethylamine or ethylenediamine as organic template agent and adding alkyl quaternary ammonium salt as organic amine accelerator into the synthesized initial gel.

In addition, in 1985, the chemist Zones S.I. of the Chevrolet company synthesized the CHA-type topological AlSi molecular sieve SSZ-13, whose structure was made of AlO₄And SiO₄The tetrahedra are connected end to end through oxygen atoms and are orderly arranged into an ellipsoidal crystal structure with an eight-membered ring structure. Due to the large specific surface area and the structural characteristics of an eight-membered ring, SSZ-13 has good thermal stability and can be used as a carrier of an adsorbent or a catalyst, such as an air purifying agent, an automobile exhaust catalyst and the like. Meanwhile, SSZ-13 also has cation exchange property and acidity adjustability, so that the catalyst has good catalytic performance on various reaction processes, including catalytic cracking and hydrocracking of hydrocarbon compounds, olefin and aromatic hydrocarbon structural reaction and the like.

The molecular sieves are prepared by a hydrothermal synthesis method. Therefore, the hydrothermal synthesis method is the most commonly used method for synthesizing molecular sieves, and a typical hydrothermal synthesis method mainly comprises the steps of firstly, uniformly mixing a silicon source, an aluminum source, a structure directing agent, alkali, water and the like to react to obtain initial sol, namely a crystallization mixture, then placing the crystallization mixture in a reaction kettle with a polytetrafluoroethylene lining and a stainless steel outer wall, sealing, and then carrying out crystallization reaction at a certain temperature and a certain autogenous pressure, like the process of earth rock making. The silicon source for synthesizing the molecular sieve can be silica sol, silica gel, sodium silicate, white carbon black, organic silicon and the like, the aluminum source can be aluminum sulfate, aluminum nitrate, sodium metaaluminate, alumina sol, organic aluminum, pseudo-boehmite and the like, and the alkali can be organic alkali, ammonia water, NaOH, KOH and the like. The alkali is an important factor influencing the synthesis of the molecular sieve, the excessive alkali can dissolve the molecular sieve, so that the product yield is reduced, and meanwhile, the introduction of the inorganic alkali can add a step for preparing the acidic molecular sieve, namely an exchange process of metal cations, so that the process cost is increased, and the wastewater treatment capacity is increased.

With the continuous expansion of the application field of zeolite and the need of scientific research and development for new properties and new performances of zeolite, a great deal of effort is put into the synthesis and preparation of novel zeolite molecular sieves, wherein, the use of heteroatoms (metal elements with heavier atomic weight) to replace framework elements for preparing zeolite molecular sieves with novel framework structures and specific properties becomes one of the effective synthesis and preparation modes of novel zeolite molecular sieves. In 1991, a zinc-silicon molecular sieve VPI-7 is prepared, and Annen then synthesizes a first high-silicon zinc-silicon molecular sieve VPI-8 with good thermal stability, and the molecular sieve has a twelve-membered ring pore system and has application potential in the cracking industry of petroleum macromolecules. The synthesis of VPI-8 mentioned in Camblor needs to add expensive organic template agents (such as TEAOH and the like), which has great limitation on further practical application, the synthesis and development of zinc-silicon molecular sieves are sunk into the glacier period till Tatsuya Okubo and the like prepare VET type zinc-silicon molecular sieves in a crystal seed guiding mode in 2014, so that the zinc-silicon molecular sieves are relegated to the field of researchers, Mark E.Davis and the like in the same year prepare nickel element ion exchange zinc-silicon molecular sieves Ni-CIT-6 and Ni-Zn-MCM-41 which show better propene oligomerization performance, and Tatsuya Okubo and the like report CHA type zinc-silicon molecular sieves with lower zinc-silicon ratio prepared in a complex system and under harsh conditions in 2017.

At present, only a few reports about CHA type topological structure zinc-silicon molecular sieves with high zinc-silicon ratio exist, the preparation process is complex, and the zinc-silicon ratio is low.

Disclosure of Invention

One of the technical problems to be solved by the invention is that the stability of the catalyst for preparing hydrocarbon by using methanol is not high, the ethylene and propylene in low-carbon olefin, especially the propylene has low selectivity and low yield, and the invention provides a CHA type topological structure zinc-silicon molecular sieve catalyst with high zinc-silicon ratio.

The second technical problem to be solved by the present invention is to provide a new preparation method of a CHA-type topological structure zinc-silicon molecular sieve catalyst with high zinc-silicon ratio.

The invention aims to solve the third technical problem of providing the application of the CHA-type topological structure zinc-silicon molecular sieve catalyst with high zinc-silicon ratio in the production of preparing low-carbon olefin from methanol.

In order to solve one of the above technical problems, the technical scheme adopted by the invention is as follows: a CHA-type topological structure zinc-silicon molecular sieve catalyst comprises the following components in parts by weight:

a) 10-99 parts of CHA type topological structure zinc-silicon molecular sieve; the molar atomic ratio of zinc and silicon of the CHA topological structure zinc-silicon molecular sieve is 0.1-2, preferably 0.2-2; such as 0.24, 0.42, 1.23.

b) 1-90 parts of a binder.

In the above technical scheme, preferably, the CHA-type topological structure zinc-silicon molecular sieve in the catalyst is 20-90 parts by weight; the binder is selected from at least one of alumina, silica or magnesia, and the weight part of the binder is 10-80 parts; the catalyst comprises at least one selected from IIIA and IIIB group elements in the periodic table or oxides thereof, and the content of the IIIA and IIIB group elements is 0.1-5 parts by weight of the catalyst.

In the above technical scheme, preferably, the CHA-type topological structure zinc-silicon molecular sieve in the catalyst is 30-80 parts by weight; 20-70 parts of binder; the IIIA group elements in the periodic table are gallium, indium or oxides thereof, and the content of the elements is 0.5-4 parts by weight of the catalyst; the IIIB group element in the periodic table is lanthanum, cerium or oxides thereof, and the content of the lanthanum, cerium or oxides is 0.5-4 parts by weight of the catalyst.

In the above technical scheme, more preferably, the catalyst contains 40 to 70 parts by weight of the CHA-type topological zinc-silicon molecular sieve; 30-60 parts of binder; the IIIA group element in the periodic table is indium or oxide thereof, and the content is 1.5-3.5 parts by weight of the catalyst; the IIIB group element in the periodic table is cerium or an oxide thereof, and the content of the cerium or the oxide is 1.5-3 parts by weight of the catalyst.

To solve the second technical problem, the invention adopts the following technical scheme: a preparation method of a CHA-type topological structure zinc-silicon molecular sieve catalyst comprises the following steps:

1) synthesizing a CHA-type topological structure zinc-silicon molecular sieve;

2) performing ammonium exchange and roasting on the CHA type topological structure zinc-silicon molecular sieve to obtain a hydrogen CHA type topological structure zinc-silicon molecular sieve, and performing active element modification on the hydrogen CHA type topological structure zinc-silicon molecular sieve by adopting an impregnation or loading method; wherein the active element is selected from IIIA group elements of the periodic table of elements and is gallium, indium or oxides thereof; the IIIB group element in the periodic table is lanthanum, cerium or oxide thereof;

3) weighing the modified molecular sieve obtained in the step 2), uniformly mixing with a binder and a pore-forming agent, then mixing water and a dilute nitric acid solution, kneading, extruding into strips and forming to obtain a columnar strip sample, drying at 80-120 ℃, and roasting at 500-650 ℃ to obtain a catalyst sample; wherein the pore-forming agent is at least one selected from sesbania powder, carboxymethyl cellulose or starch.

The synthesis method of the CHA-type topological structure zinc-silicon molecular sieve comprises the following steps:

(1) according to the formula nZnO/nSiO₂N template agent T/nH₂Dissolving a zinc source and a template agent T in deionized water, and fully and uniformly stirring to obtain a solution A, wherein O is the molar ratio of 1: 0.1-10: 1-200: 10-1000, and n represents the molar number;

(2) placing the solution A at a temperature of 30-60 ℃, adding CHA topological structure type all-silicon molecular sieve seed crystals (accounting for 0.25-5% of the total dry basis material mass of the reaction) accounting for 0.5-10% of the total dry basis material mass of the reaction and the residual template agent under stirring, and stirring in a closed manner until the mixture is uniformly mixed to obtain a solution B;

(3) and (2) adding a silicon source and an additive (accounting for 0.25-5% of the total dry basis material mass of the reaction) into the solution B, hermetically stirring at 60-100 ℃ until a uniform crystallized mixed solution is formed, crystallizing the crystallized mixed solution at 140-220 ℃ for 1-7 days, filtering, washing, drying and roasting to obtain the CHA type topological structure zinc-silicon molecular sieve product.

In order to solve the third technical problem, the technical scheme adopted by the invention is as follows: a method for preparing olefin by methanol conversion comprises the steps of taking methanol as a raw material, reacting in a fixed bed reactor at the temperature of 400-600 ℃, the reaction pressure of 0.1-10 Mpa, and the weight space velocity of the methanol of 0.1-20 h^-1The raw material passes through a catalyst bed layer and contacts with any one of the catalysts to generate olefin.

In the technical scheme, the preferable range of the reaction temperature is 450-550 ℃, the preferable range of the reaction pressure is 0.5-5 Mpa, and the preferable range of the weight space velocity is 2-10 h^-1。

The modified CHA-type topological structure zinc-silicon molecular sieve provided by the invention can be prepared by physical and chemical methods such as impregnation, chemical adsorption, chemical deposition, ion exchange and the like, and the preferable scheme is that an aqueous solution containing active components is subjected to isometric impregnation, wherein the active components are gallium, indium, lanthanum and cerium, sesbania powder and dilute nitric acid are added after the active components are stirred for a period of time, and a finished product is prepared by kneading and extruding strips. Drying at 80-120 ℃, and roasting in an air atmosphere to obtain the catalyst, wherein the roasting temperature is 500-650 ℃, and the roasting time is 4-10 h.

The CHA topological structure zinc-silicon molecular sieve provided by the invention has the pore channel structure characteristics of the CHA molecular sieve and the acid characteristics caused by unique Zn heavy atoms, the CHA topological structure zinc-silicon molecular sieve and the CHA topological structure zinc-silicon molecular sieve have good synergistic effect, the supported gallium and indium elements have good dehydrogenation performance for hydrocarbons, and can effectively form an internal and external synergistic mechanism with a molecular sieve framework to enhance the reaction performance, the lanthanide element can effectively improve the carbon deposition resistance of the molecular sieve and can also effectively inhibit the dealuminization behavior of the molecular sieve under the hydrothermal condition, and the selectivity and the yield of ethylene and propylene are improved by means of increasing the synergistic effect, the dehydrogenation effect, the carbon deposition resistance and the like of the catalyst.

In a fixed bed reactor, the reaction temperature is 400-600 ℃, the reaction pressure is 0.1-10 Mpa, and the weight space velocity of methanol is 0.1-20 h^-1(ii) a The preferable scheme is that the reaction temperature is 450-550 ℃, the reaction pressure is 0.5-5 Mpa, and the weight space velocity is 2-10 h^-1Under the condition, the high zinc-silicon ratio CHA-type topological structure zinc-silicon molecular sieve catalyst uses methanol as a raw material, the conversion rate of the raw material is 100%, the yield of diene (ethylene and propylene) as a product can reach 89.6%, wherein the yield of propylene can reach 60.7%, and meanwhile, the catalyst has good stability and obtains better technical effects.

The invention is further illustrated by the following specific examples.

Drawings

Figure 1 is the XRD pattern of the product of example 3.

FIG. 2 is an SEM photograph of the product of example 3.

FIG. 3 is a graph of the absorption edges EXAFS of the zinc and potassium elements for the product of example 3 and zinc silicate and zinc oxide.

Detailed Description

[ example 1 ]

312.36g of zinc nitrate (Zn (NO) were weighed out₃)₂·6H₂O, 1.04mol) was added to 8353.66g of distilled water, followed by 2219.81g of amantadine (TMADAOH, 40 w)t%, 14.70mol), then transferring the uniformly mixed solution to a 30 ℃ oil bath environment, adding all-silicon CHA type seed crystal accounting for 0.25% of the total dry basis weight of reactants and 982.43g of amantadine (TMADAOH, 40 wt%, 6.50mol) under stirring, stirring for 5 hours in a closed manner, adding 1202.76g of silica sol (40 wt%, 8.02mol) and lithium hydroxide (LiOH) accounting for 5% of the total dry basis weight of reactants into the reaction solution, heating the oil bath to 60 ℃, and continuing stirring, wherein the molar ratio of the crystallization mixed solution is controlled as follows: nZnO/nSiO₂N template agent T/nH₂O is 1: 7.71: 20.38: 587.42, after completely and uniformly mixing, placing the crystallized mixture in a pressure-resistant container with a polytetrafluoroethylene lining for crystallization at 140 ℃ for 3d, filtering and washing the product, drying at 100 ℃, heating to 500 ℃ and roasting at constant temperature to obtain the Zn-Si molecular sieve product ZnC-1 with Zn-Si ratio and CHA type topological structure, wherein the final Zn-Si molar atomic ratio of the product is 0.18 as measured by a plasma Perkin-Elmer 3300DV ICP analyzer.

[ example 2 ]

20.13g of zinc acetate (Zn (OAc))₂·2H₂O, 0.09mol) is added into 333.35g of distilled water, then 12.98g of triethylene diamine (DABCO, more than or equal to 98wt percent, 0.12mol) and 110.42g of triethylamine (TEA, 1.09mol) are added and stirred evenly, then the evenly mixed solution is transferred into an oil bath environment at 60 ℃, all-silicon CHA type seed crystal accounting for 5 percent of the total weight of the dry base of the reactant, 27.02 of triethylene diamine (DABCO, more than or equal to 98wt percent, 0.24mol) and 89.58g of triethylamine (TEA, 0.88mol) are added under the stirring state, after 2.5 hours of closed stirring, 3.62g of white carbon black (SiO 2.62 g of white carbon black) is added₂99% by weight, 0.06mol) and 0.25% by weight, based on the total weight of the reactants on a dry basis, of magnesium hydroxide (Mg (OH)₂) Adding the mixture into the reaction solution, heating the oil bath to 100 ℃, and continuing stirring, wherein the molar ratio of the crystallized mixed solution is controlled as follows: nZnO/nSiO₂N template agent T/nH₂O is 1: 0.67: 25.89: 205.78, after completely mixing uniformly, the crystallized mixture is put into a pressure-resistant container with a polytetrafluoroethylene lining for crystallization for 0.5d at 220 ℃, the product is dried at 80 ℃ after being filtered and washed, and then is heated to 550 ℃ for constant temperature roasting, thus obtaining the Zn-high zinc-silicon ratio CHA type topological structureZnC-2 of the zinc-silicon molecular sieve product, and the final zinc-silicon molar atomic ratio of the product is 1.23 measured by a plasma Perkin-Elmer 3300DV ICP analyzer.

[ example 3 ]

1039.99g of zinc sulfate (ZnSO) were weighed out₄·6H₂O, 36.17mol) was added to 5335.66g of distilled water, then 1259.84g of amantadine (TMADAOH, 98 wt%, 8.32mol) and 3254.12g of di-n-propylamine (DPA, 32.16mol) were added and stirred uniformly, then the uniformly mixed solution was transferred to an oil bath environment of 50 ℃, all-silicon CHA type seed crystals 2.9% by weight based on the total dry weight of the reactants and 712.43g of TMADAOH (98 wt%, 4.71mol) and 5654.52g of di-n-propylamine (DPA, 55.88mol) were added under stirring, after stirring hermetically for 5 hours, 21126.22g of silica sol (40 wt%, 140.84mol) and lithium hydroxide (LiOH) and magnesium hydroxide (Mg (OH) 4.9% by weight based on the total dry weight of the reactants₂) Adding the mixture into the reaction solution, heating the oil bath to 80 ℃, and continuing stirring, wherein the molar ratio of the crystallized mixed solution is controlled as follows: nZnO/nSiO₂N template agent T/nH₂And O is 1: 3.89: 2.79: 27.66, after completely and uniformly mixing, placing the crystallized mixture in a pressure-resistant container with a polytetrafluoroethylene lining for crystallization at 160 ℃ for 2.5d, filtering and washing a product, drying the product at 90 ℃, heating the product to 600 ℃, and roasting the product at constant temperature to obtain a Zn-high Zn-Si ratio CHA type topological structure Zn-Si molecular sieve ZnC-3, wherein the final Zn-Si molar atomic ratio of the product is 0.24 measured by a plasma Perkin-Elmer 3300DV ICP analyzer. The obtained sample is compared with zinc phosphate and zinc oxide after the EXAFS characterization, and the zinc element in the ZnC-3 sample is completely present in the framework structure of the molecular sieve (see the attached figure 3 in the specification).

[ example 4 ]

66.66g of zinc oxide (ZnO, 0.82mol) is weighed into 888.65g of distilled water, then 1122.63g of tetraethylammonium hydroxide (TEAOH, 25 wt%, 1.91mol) and 204.78g of diethylenetriamine (DETA, 1.98mol) are added and stirred uniformly, then the uniformly mixed solution is transferred into an oil bath environment at 45 ℃, and all-silicon CHA type seed crystals accounting for 4.5% of the total weight of the dry basis of reactants and 888.83g of tetraethylammonium hydroxide (TEAOH, 25 wt%, 1.09mol) are added under stirringmol) and 156.22g of diethylenetriamine (DETA, 1.51mol), stirring for 3.9h in a closed manner, then adding 126.23g of white carbon black (99 wt%, 2.01mol) and lithium hydroxide (LiOH) accounting for 1.5% of the total weight of the dry bases of reactants into the reaction solution, heating the oil bath to 75 ℃, and continuing stirring, wherein the molar ratio of the crystallization mixed solution is controlled as follows: nZnO/nSiO₂N template agent T/nH₂And (3) O is 1: 2.45: 5.83: 196.76, after completely and uniformly mixing, placing the crystallized mixture in a pressure-resistant container with a polytetrafluoroethylene lining for crystallization at 190 ℃ for 1.5d, filtering and washing a product, drying the product at 90 ℃, heating the product to 580 ℃, and roasting the product at a constant temperature to obtain a Zn-high Zn-Si ratio CHA type topological structure zinc-silicon product molecular sieve ZnC-4, wherein the final Zn-Si molar atomic ratio of the product is 0.42 as measured by a plasma Perkin-Elmer 3300DV ICP analyzer.

[ examples 5 to 20 ]

According to the method of example 3, the raw materials are shown in table 1, different proportions of the reaction materials are controlled (table 2), and Zn-high Zn-Si ratio and high Zn-Si ratio CHA type topological structure Zn-Si molecular sieves are respectively synthesized, wherein the Si/Al ratio of the seed crystal, the content of the seed crystal and the additive in the raw materials and the Si/Al atomic ratio of the product are shown in table 3.

TABLE 1

TABLE 2

Examples	Reactant proportioning composition
		5	nZnO/nSiO₂N template agent T/nH₂O＝1∶0.1∶15∶999
6	nZnO/nSiO₂N template agent T/nH₂O＝1∶4.2∶44∶449
		7	nZnO/nSiO₂N template agent T/nH₂O＝1∶8.8∶59∶99
8	nZnO/nSiO₂N template agent T/nH₂O＝1∶10∶5∶37
		9	nZnO/nSiO₂N template agent T/nH₂O＝1∶0.9∶26∶85
10	nZnO/nSiO₂N template agent T/nH₂O＝1∶5∶74∶230
		11	nZnO/nSiO₂N template agent T/nH₂O＝1∶7∶199∶856
12	nZnO/nSiO₂N template agent T/nH₂O＝1∶9.5∶104∶333
		13	nZnO/nSiO₂N template agent T/nH₂O＝1∶0.5∶11∶65
14	nZnO/nSiO₂N template agent T/nH₂O＝1∶1.1∶104∶430
		15	nZnO/nSiO₂N template agent T/nH₂O＝1∶2.5∶94∶703
16	nZnO/nSiO₂N template agent T/nH₂O＝1∶6∶49∶219
		17	nZnO/nSiO₂N template agent T/nH₂O＝1∶0.3∶72∶223
18	nZnO/nSiO₂N template agent T/nH₂O＝1∶0.7∶141∶120
		19	nZnO/nSiO₂N template agent T/nH₂O＝1∶3.8∶134∶667
20	nZnO/nSiO₂N template agent T/nH₂O＝1∶1.5∶185∶556

[ example 21 ]

Preparation and modification of catalysts

The preparation method of the catalyst comprises the following steps:

(1) modification treatment of CHA type topological structure zinc-silicon molecular sieve with high zinc-silicon ratio

Taking 20 g of ZnC-1 molecular sieve, 2.5mL of 0.39mol/L gallium nitrate solution, 10.2mL of 0.12mol/L indium nitrate solution and 10.2mL of 0.12mol/L lanthanum nitrate solution, stirring and evaporating at 100 ℃, drying and roasting to obtain the gallium indium lanthanum modified high zinc silicon ratio CHA type topological structure zinc silicon molecular sieve raw powder.

(2) Preparation of the catalyst

Taking 9.95g of the modified molecular sieve prepared in the step (1) and gamma-Al₂O₃4.26g and 1.45g of sesbania powder are mixed, 23.66mL of 1.5 wt% dilute nitric acid is added, kneading and strip extrusion molding are carried out, drying is carried out for 12h at 100 ℃, then roasting is carried out for 6.0h at 550 ℃, the crushed sesbania powder is sieved to obtain a 20-40 mesh part, the part is put into a fixed bed reactor, the reaction temperature is 470 ℃, the reaction pressure is 2.5MPa, and the weight space velocity is 4.9h^-1The results are shown in Table 4.

TABLE 3

[ examples 22 to 40 ]

The composite molecular sieves prepared in the above examples were modified and evaluated according to the method of example 21, and the compositions of the prepared catalysts and the evaluation results thereof are shown in table 4.

[ example 41 ] to provide a pharmaceutical composition

ZnC-16 molecular sieve was selected and loaded without selecting any one element, and evaluated under the conditions of example 32, and the evaluation results are shown in Table 4.

[ example 42 ]

ZnC-16 molecular sieve was taken, and only indium element was supported according to the modification method of example 32, and evaluated under the conditions of example 22, and the evaluation results are shown in Table 4.

[ example 43 ]

ZnC-16 molecular sieve was taken, only cerium element was supported according to the modification method of example 32, and evaluated under the conditions of example 22, and the evaluation results are shown in Table 4.

[ COMPARATIVE EXAMPLE 1 ]

The VPI-7 molecular sieve was modified and evaluated according to the procedure of example 23 to obtain a catalyst, and the evaluation results are shown in Table 4.

VPI-7：

At room temperature, byn(Na₂O)：n(SiO₂)：n(ZnO)：n(H₂O) ═ 0.55: 1: 0.28: 40 sequentially taking stoichiometric NaOH and H₂O、SiO₂、Zn(NO₃)₂4H₂And adding O into a stainless steel self-pressure reaction kettle with a polytetrafluoroethylene lining, uniformly stirring, sealing, and crystallizing for 7d in an oven at 200 ℃ to obtain VPI-7.

[ COMPARATIVE EXAMPLE 2 ]

The VPI-8 molecular sieve was modified and evaluated according to the procedure of example 23 to obtain the catalysts, and the evaluation results are shown in Table 4.

VPI-8:

Under the condition of room temperature, the ratio of n (ZnO): n (SiO)₂)：n(Li₂O)：n(TEABr)：n(H₂O) ═ 0.1: 1: 0.3: 0.4: 30 in turn take stoichiometric quantities of H₂O、Zn(NO₃)₂4H₂O、TEABr、SiO₂And LiOH, adding into a stainless steel self-pressure reaction kettle with a polytetrafluoroethylene lining, uniformly stirring, sealing, and crystallizing in an oven at 180 ℃ for 8d to obtain VPI-8.

[ COMPARATIVE EXAMPLE 3 ]

Zinc-silicon type CHA molecular sieve (zinc-silicon ratio is 0.02) is prepared according to the method in the literature (chem.Eur.J.2018,24, 808-812), and the synthesis ratio SiO is given according to the document₂:x ZnO:0.42TMAdaOH:0.08LiOH:30H₂O, x is 0.02-0.06, SiO in maximum ratio of Zn to Si₂0.06ZnO charge, reacted at 150 ℃ for 7 days to obtain a comparative sample, which was actually measured as SiO by ICP₂0.03 ZnO. The catalyst thus obtained was modified and evaluated in accordance with the procedure of example 23, and the evaluation results are shown in Table 4.

[ COMPARATIVE EXAMPLE 4 ]

The zinc oxide powder and the all-silicon SSZ-13 molecular sieve are mechanically mixed according to the proportion of zinc and silicon in example 20, and the mixture is evaluated according to the modification and manner of example 23, and the evaluation results of the prepared catalyst are shown in Table 4.

[ COMPARATIVE EXAMPLE 5 ]

The zinc oxide powder and the all-silicon SSZ-13 molecular sieve were mechanically mixed according to the proportion of zinc and silicon in example 11, and evaluated according to the modification and manner of example 26 to obtain the catalyst, and the evaluation results are shown in Table 4.

[ COMPARATIVE EXAMPLE 6 ]

The zinc oxide powder and the all-silicon SSZ-13 molecular sieve are mechanically mixed according to the proportion of zinc and silicon in example 10, and the mixture is evaluated according to the modification and manner of example 30, and the evaluation results of the prepared catalyst are shown in Table 4.

TABLE 4

[ example 44 ]

The catalyst obtained in example 21 was used, and the reaction temperature was 400 ℃, the reaction pressure was 2.0MPa, and the weight space velocity was 1.5h^-1The results are shown in Table 5

[ examples 45 to 54 ]

The catalyst obtained in example 21 was evaluated under different conditions of reaction temperature, reaction pressure and weight space velocity, and the reaction conditions and the evaluation results are shown in Table 5.

TABLE 5

Claims

1. A CHA-type topological structure zinc-silicon molecular sieve catalyst comprises the following components in parts by weight:

a) 10-99 parts of CHA type topological structure zinc-silicon molecular sieve; the molar atomic ratio of zinc and silicon of the CHA topological structure zinc-silicon molecular sieve is 0.1-2, preferably 0.2-2;

b) 1-90 parts of a binder.

2. The CHA-type topological structure zinc-silicon molecular sieve catalyst of claim 1, wherein the CHA-type topological structure zinc-silicon molecular sieve is 20-90 parts by weight; the preferable content is 30-80 parts; more preferably 40 to 70 parts.

3. The CHA-type topological structure zinc silicate molecular sieve catalyst of claim 1, wherein the binder is 20-70 parts by weight; the preferable content is 30 to 60 parts.

4. The CHA-type topological zinc silicalite molecular sieve catalyst of claim 1, wherein the binder is selected from at least one of alumina, silica and magnesia.

5. The CHA-type topological structure zinc silicate molecular sieve catalyst of claim 1, wherein the catalyst comprises at least one selected from the group consisting of IIIA and IIIB elements of the periodic Table of elements or oxides thereof, and the content of IIIA and IIIB elements is 0.1-5 parts by weight of the catalyst; preferably, the group IIIA elements in the periodic table of elements are gallium, indium or oxides thereof, and the content of the elements is 0.5-4 parts by weight of the catalyst; the IIIB group element in the periodic table is lanthanum, cerium or oxides thereof, and the content of the lanthanum, cerium or oxides is 0.5-4 parts by weight of the catalyst.

6. The CHA-type topological structure zinc silicate molecular sieve catalyst of claim 5, wherein the selected group IIIA elements in the periodic Table of elements is indium or its oxide, and the content is 1.5-3.5 parts by weight of the catalyst; the IIIB group element in the periodic table is cerium or an oxide thereof, and the content of the cerium or the oxide is 1.5-3 parts by weight of the catalyst.

7. The process of preparing the CHA-type topological zinc silicalite molecular sieve catalyst of claim 1, comprising the steps of:

1) synthesizing a CHA-type topological structure zinc-silicon molecular sieve;

8. A method for preparing hydrocarbon through methanol conversion comprises the steps of taking methanol as a raw material, reacting in a fixed bed reactor at the temperature of 400-600 ℃, the reaction pressure of 0.1-10 Mpa, and the weight space velocity of the methanol of 0.1-20 h^-1Passing the feedstock through a catalyst bed and contacting the feedstock with any one of the catalysts of claims 1 to 6 to form hydrocarbons.

9. The method for preparing hydrocarbon through methanol conversion according to claim 8, wherein the reaction temperature is 450-550 ℃, the reaction pressure is 0.5-5 MPa, and the weight space velocity is 2-10 h^-1。

10. The CHA-type topological structure zinc silicate molecular sieve catalyst of claims 1-6, for use in a reaction for producing lower olefins from methanol.