77 results about "Acid strength" patented technology

The invention discloses a preparation method of an H beta molecular sieve catalyst, which comprises the following steps: carrying out acid-base alternate etching on a roasted H beta molecular sieve according to an acid-base sequence by adopting an acid-base alternate etching method, and optionally carrying out ion exchange and roasting on a product obtained after alkali etching to obtain the H beta molecular sieve catalyst. According to the method disclosed by the invention, the H beta molecular sieve is modified through acid-base alternate etching, so that not only is abundant binary micro / mesopores constructed, the specific surface area of the molecular sieve increased and the mass transfer effect enhanced, but also the required acid strength and appropriate L and B acid sites are provided by changing the acid strength and the acid type on the pore channel and the surface of the catalyst subjected to acid-base etching. The prepared H beta molecular sieve catalyst is applied to Friedel-Crafts acylation reaction of anisole and acetic anhydride, and the catalytic activity is remarkably improved.

The invention discloses a catalyst for preparing mesitylene. The catalyst is prepared from the following components: 65%-80% of a molecular sieve, 15%-30% of gamma-Al2O3 and 0.25%-2.5% of a metal element. The preparation method comprises the following steps: uniformly mixing a molecular sieve and a gamma-Al2O3 precursor substance respectively, adding a peptizing agent and an extrusion aid, and kneading to obtain an initial product; carrying out extrusion forming on the initial product, drying and roasting at high temperature to obtain a catalyst body; and carrying out equivalent-volume impregnation on the catalyst body and a metal salt solution for 24-26 hours, taking out and drying, and finally roasting at high temperature to obtain the mesitylene catalyst. The prepared catalyst has acid strength and pore size suitable for isomerization of 1, 2, 4-trimethylbenzene, dealkylation reaction and disproportionation reaction are effectively inhibited, generation of xylene and tetramethylbenzene is reduced, the selectivity of isomerization reaction can reach 67%, the yield of 1, 2, 4-trimethylbenzene can reach 24.5%, and waste of raw materials is reduced.

The invention discloses a bifunctional composite catalyst for preparing aviation kerosene through direct hydrogenation of carbon dioxide. The bifunctional composite catalyst is prepared from the H-ZSM-5 zeolite molecular sieve and a composite metal oxide InZnZrOx. Wherein the H-ZSM-5 zeolite molecular sieve is obtained by an inventor through a hydrothermal method, the appearance, the acid strength and the acid amount of the molecular sieve can be accurately controlled through the method, a hierarchical pore structure in a pore channel can be increased, and the selectivity of aviation kerosene components can be well improved; the problems that the diffusion of the heavy carbon aromatic hydrocarbon product in the pore channel of the zeolite molecular sieve is blocked, so that the catalyst is easy to deposit carbon, and the acidic site is covered are solved to a great extent; the composite metal oxide InZnZrOx can be prepared through flexible and efficient coprecipitation, and the problems that in an InZnZrOx / flaky hierarchical pore H-ZSM-5 molecular sieve difunctional composite catalyst, the metal oxide dispersity is low, and the catalytic activity is low are solved.

The present invention provides an onium salt capable of generating an acid with moderate acid strength and low diffusion, a chemically amplified positive-type resist composition containing the same, and a method for forming a resist pattern using the resist composition. [Solution] An onium salt represented by the following formula (A). TIFF2026090779000330.tif29102

The present invention provides an alkane isomerization catalyst and a preparation method thereof. The preparation method comprises the following steps: (1) subjecting a composite oxide gel to temperature-programmed sulfurization to obtain a sulfur-modified catalyst intermediate; and (2) impregnating the sulfur-modified catalyst intermediate in step (1) with a precious metal source, drying, and calcining the catalyst to obtain an alkane isomerization catalyst. The present invention utilizes temperature-programmed vapor-phase sulfurization technology to simultaneously perform the drying, sulfurization, and crystallization processes of the composite oxide gel, thereby improving the structure and acid strength of existing sulfated zirconia-based catalysts and enhancing their catalytic activity and product selectivity in alkane isomerization reactions.

Provided are new compounds that are free of perfluoromethyl and perfluoromethylene groups, are easily decomposed by light irradiation, and generate sulfonic acid having high acid strength.　The present invention is a compound that is a salt of an anion represented by formula (a-1) or (a-2) and a cation. In the formula, R1 represents a hydrogen atom, a hydrocarbon group, or a heterocyclic group, or a group in which two or more of said groups are bonded via a linking group. R10 represents a fluorine atom, an aromatic hydrocarbon group, or an aromatic heterocyclic group. R20 represents a hydrogen atom, a halogen atom, an optionally substituted hydrocarbon group, an optionally substituted heterocyclic group, or a group having a group in which said group and a linking group are bonded. n is 0 or 1.

This invention provides a zinc-modified composite molecular sieve catalyst, its preparation method, and its application, relating to the field of molecular sieve catalysts. The zinc-modified composite molecular sieve catalyst comprises zinc and a composite molecular sieve, wherein the composite molecular sieve is an MCM-22 / MCM-41 composite molecular sieve, and the zinc content is 1%-10% by weight of the total weight of the zinc-modified composite molecular sieve catalyst. The catalyst provided by this invention features an MCM-22 / MCM-41 composite molecular sieve with a microporous-mesoporous composite structure, exhibiting good thermal stability and resistance to decomposition during the preparation of diisopropylnaphthalene, and possessing high overall acid strength. Zinc modification adjusts the ratio and intensity distribution of Brønsted (B) and Lewis (L) acids in the MCM-22 / MCM-41 composite molecular sieve, optimizing the synthesis process, enhancing the alkylation performance of the catalyst, and improving the conversion rate of raw materials and the selectivity of diisopropylnaphthalene.

The invention relates to the technical field of light alkane normal isomerization, and discloses an alkane normal isomerization catalyst and a preparation method and application thereof, the catalyst comprises an acidic active component SO4 < 2-> / ZrO2, an all-silicon molecular sieve with an MFI structure and alumina; wherein the ratio of the mass of the acidic active component in terms of ZrO2 to the mass of the all-silicon molecular sieve in terms of SiO2 is 1: (0.1-1). According to the catalyst, the acid center of the catalyst is modulated through the all-silicon molecular sieve with the MFI structure, and the distribution of the acid center of the catalyst is optimized under the condition that the active phase structure and the acid strength of the catalyst are not changed, so that the catalyst shows better activity and selectivity in the normal isomerization reaction of light alkanes.

This invention relates to a solid acid catalyst, its preparation, and its application in the catalytic dehydration of bioethanol to ethylene. The active component of the catalyst comprises two parts: (1) a main catalyst and (2) a co-catalyst. This invention utilizes a suitable amount of chelating agent to chelate with the metal in the heteropolyacid, thereby inhibiting the aggregation of heteropolyacid particles and improving dispersion; and by introducing other functional groups to modulate the acid strength and acid density of the catalyst, it inhibits the formation of carbon deposits, thus improving the stability of the catalyst. The catalyst prepared under mild conditions and with a stable and controllable process, the resulting catalyst has advantages such as low reaction temperature, high activity, good stability, and strong resistance to carbon deposition.

The invention discloses a carrier for a diesel hydrofining catalyst as well as a preparation method and application of the carrier, and belongs to the technical field of hydrofining catalyst carriers. According to the carrier prepared by the method, halogen elements are directly introduced, for example, hydroxyl groups on the surface of the carrier are replaced by adding fluorine, so that the capability of dissociating protons is enhanced. Meanwhile, fluorine can increase the number of B acid centers and the acid strength on the surface of the catalyst, reduce Lewis acid centers, enhance the cracking function of the catalyst and reduce coke formation and carbon deposition on the surface of the catalyst. According to the diesel oil hydrofining catalyst, a Mo-Ni-P combination is adopted as a hydrogenation active component, a proper pore structure and a large specific surface area can be provided for the catalyst by combining a carrier, reactant molecules can approach to the active component on the surface, and conditions are provided for fully playing the role of the active component; the content of strong acid on the surface of the carrier is reduced, so that catalyst deactivation caused by coking reaction is slowed down, and the stability of the catalyst is enhanced.

The invention discloses a cation modified gallium-silicon MTW molecular sieve catalyst as well as a preparation method and application thereof, and relates to the technical field of molecular sieve catalysts. The cation modified gallium-silicon MTW molecular sieve catalyst provided by the invention at least comprises a gallium-silicon MTW molecular sieve; the alkali metal cations are loaded on the gallium-silicon type MTW molecular sieve; the acid sites of the cation modified gallium silicon type MTW molecular sieve catalyst comprise a Bronsted acid and a Lewis acid. The cation-modified gallium-silicon MTW molecular sieve catalyst prepared by the invention takes gallium and silicon as main framework elements, and after being modified by alkali metal cations, the cation-modified gallium-silicon MTW molecular sieve catalyst has appropriate acid strength, uniform acid site distribution and unique one-dimensional twelve-membered ring pore channel shape-selective effect of the MTW molecular sieve, and is used for preparing acrylic acid by dehydrating lactic acid; the activity, selectivity and stability of the catalyst in a lactic acid dehydration reaction are improved.

The present application relates to the technical field of molecular sieve preparation, and provides a surface silicon-rich binderless ZSM-5 molecular sieve catalyst and a preparation method and application thereof.The overall SiO2 / Al2O3 of the ZSM-5 molecular sieve catalyst is 86-203, the SiO2 / Al2O3 of a surface layer with a depth of 2-10 nm is 8-33% higher than the overall SiO2 / Al2O3; the acid strength measured by using Hammett indicator n-butylamine titration method is H0≤+2.27, and the content of surface acid sites is ≤0.02 mmol / g; and the ZSM-5 molecular sieve catalyst is a shaped body without amorphous phase.The surface silicon-rich binderless ZSM-5 molecular sieve catalyst provided by the present application does not contain inert adhesive, has extremely weak surface acidity, can improve the catalytic effect, and reduces the generation of by-products.In addition, the preparation method provided by the present application is simple in process and suitable for industrial production.

The invention discloses a phosphotungsten / molybdenum synergistic modified supported catalyst as well as a preparation method and application thereof, and belongs to the technical field of catalysis. The catalyst takes gamma-Al2O3 as a carrier and takes transition metal oxide and / or phosphide as an active component. The catalyst is prepared by precursor dipping, drying at 80-120 DEG C and calcining at 300-500 DEG C. The synergistic effect of phosphorus, tungsten and molybdenum is utilized, so that acid sites are newly increased, the acid strength is enhanced, and agglomeration of active components is inhibited. The catalyst provided by the invention has excellent catalytic performance, has higher reaction activity under the pressure of 0.5 Mpa, which is far lower than the pressure provided in the prior art, and has the characteristics of high target product yield, good catalyst stability, simple preparation process and low production cost.

Provided is a BEA-type zeolite having high acid strength and crystallinity in a wide range of SiO2 / Al2O3 molar ratios. One of the present invention is a BEA-type zeolite in which, in an NH3-TPD spectrum when the temperature is increased at 10 DEG C / min by an ammonia programmed temperature desorption method (NH3-TPD method), the peak of a peak derived from adsorption to an acid site of the BEA-type zeolite is within the range of 340 DEG C to 500 DEG C (inclusive), and the peak of the peak derived from adsorption to the acid site of the BEA-type zeolite is within the range of 340 DEG C to 500 DEG C (inclusive). The ratio (A / B) of the maximum diffraction intensity (A) of the peak of the BEA-type zeolite to the diffraction intensity (B) of the (111) plane of Si of a standard substance 640c issued by the National Standard of America and the Institute of Technology, in an X-ray diffraction spectrum measured by an X-ray diffraction method using a CuK [alpha] ray, is 25 or more.

The application discloses a kind of low ring body hydrogen-containing silicone oil and preparation method thereof, belong to the technical field of silicone material.The preparation method includes: preparation gradient acid strength core-shell solid acid catalyst;Siloxane raw materials are mixed, and the raw material mixed solution is obtained by dehydration and deoxidation pretreatment;The catalyst is loaded in fixed bed reactor, and the raw material mixed solution is continuously introduced to carry out ring-opening polymerization reaction;Reaction effluent is continuously sent into thin film evaporator, first remove unreacted monomer, then remove ring body and low boiling point substance, collect the product at the bottom of kettle, i.e.low ring body hydrogen-containing silicone oil.The application designs a kind of gradient acid strength core-shell solid acid catalyst, the core is sulfated zirconium oxide, shell is 2-3nm mesoporous SiO2.Limited effect is used in pore, and the limited ring-opening polymerization of cyclosiloxane is realized in fixed bed reactor, chain back-bite into ring is inhibited from space.Combination continuous thin film evaporation separates product in time, so that ring body content is lower than traditional scheme.

The present invention relates to the technical field of molecular sieve preparation. Provided are a binderless ZSM-5 molecular sieve catalyst having a silicon-rich surface, and a preparation method therefor and the use thereof. The overall SiO2 / Al2O3 ratio of the ZSM-5 molecular sieve catalyst is 50-500, and the surface-layer SiO2 / Al2O3 ratio of the ZSM-5 molecular sieve catalyst is 5-50% higher than the overall SiO2 / Al2O3 ratio; and the content of a surface acid site having an acid strength H0 of greater than or equal to +2.27 in the ZSM-5 molecular sieve is less than or equal to 0.04 mmol / g. The binderless ZSM-5 molecular sieve catalyst having a silicon-rich surface provided by the present invention does not contain an inert binder, has an extremely weak surface acidity, and can improve the catalytic effect and reduce the production of by-products. In addition, the preparation method provided by the present invention has a simple process and is suitable for industrial production.

The invention provides a method for preparing 5-hydroxymethylfurfural from fructose, which comprises the following steps: dissolving the fructose in a mixed solvent of an organic solvent and water, contacting with a catalyst, placing in a closed autoclave, heating, stirring and reacting in an inert atmosphere, cooling, filtering the reaction liquid to remove solid particles, and storing the 5-hydroxymethylfurfural in the filtrate; the catalyst is a polypeptide modified SAPO-34 molecular sieve catalyst. The SAPO-34 molecular sieve is grafted with polypeptide, the surface of the catalyst has good biocompatibility, adsorption of fructose molecules can be enhanced, meanwhile, the catalyst has certain hydrophobicity, water generated on active sites in situ in the reaction process is removed in time, it can be guaranteed that the acid strength of the catalyst is at a high level, and the reaction time is shortened. And meanwhile, the timely removal of water also inhibits the occurrence of side reaction rehydration, and the water quickly diffuses from the acid center to promote the reaction balance, so that the problems of low conversion rate and poor selectivity of HMF synthesis in the prior art are solved.

The preparation method of the liquid catalyst comprises the following steps: weighing a certain amount of heteropoly acid, dissolving the heteropoly acid in water to obtain a solution A, weighing a corresponding amount of carboxylic acid functionalized imidazolium salt, dissolving the carboxylic acid functionalized imidazolium salt in water to obtain a solution B, slowly dropwise adding the solution A into the solution B under stirring, and reacting for a period of time to obtain a mixture C; and separating, washing and drying the mixed solution C to obtain the product heteropolyacid ionic liquid. Compared with the traditional solid acid catalyst, the catalyst has the advantages of adjustable acid strength, high structural stability, strong designability and the like, and is expected to become a new process for efficiently catalyzing the CO2 desorption process and reducing the energy consumption of CO2 capture by an alcohol amine method.

The invention relates to the technical field of catalyst preparation, in particular to a modified ZSM-5 molecular sieve, a preparation method thereof and a hydrocarbon cracking reaction. According to the hydrocarbon cracking reaction provided by the invention, the pore property and the acid property of the ZSM-5 molecular sieve are regulated and controlled based on the introduction of manganese species with different valence states in the ZSM-5 molecular sieve, more importantly, the acid strength and the B / L acid ratio of the ZSM-5 molecular sieve are increased while the acid density of the ZSM-5 molecular sieve is increased, and the series of modified ZSM-5 molecular sieves have different acid structures and present gradient change of the acid property, so that the performance of the ZSM-5 molecular sieve is improved. Along with the increase of the valence state of manganese in the manganese species, the acid amount of the ZSM-5 molecular sieve, especially the strong B / L acid ratio of the ZSM-5 molecular sieve, is sequentially increased, so that the product yields of ethylene and propylene can be regulated and controlled according to the change of the microstructure and the acidic structure of the catalyst. And the service life of the modified ZSM-5 molecular sieve is greatly prolonged, the hydrocarbon catalytic cracking performance is improved, and the conversion rate, the low-carbon olefin yield and the catalytic stability are remarkably improved.

A method for preparing a hydroxylamine aqueous solution by catalytic hydrolysis of butanone oxime belongs to the technical field of hydroxylamine preparation. The present invention uses low-temperature catalytic hydrolysis of butanone oxime and extraction and separation to obtain a hydroxylamine aqueous solution; the catalyst undergoes a sulfhydryl addition reaction with vinylguanamine and 4-allylcatechol through a macroporous styrene thiol resin to obtain a guanidine resin, which is then sulfonated to obtain a guanidine solid acid catalyst. The guanidine solid acid catalyst has higher acid strength and stronger catalytic activity, can more effectively promote the hydrolysis of butanone oxime, can significantly increase the hydrolysis rate and conversion rate of butanone oxime, and has good economic benefits.

This invention discloses a floating catalyst and its application in the synthesis of p-hydroxyphenylhydantoin. Copper and manganese co-doped nano-TiO2 hydrosol is loaded onto fly ash cenospheres to form a gel. The dried gel is sintered at 600-700℃ to obtain a floating catalyst with fly ash cenospheres as the support. Its chemical composition is: SO42- 2‑ / TiO2-CuO-Mn2O3 / fly ash cenospheres; its mass composition is: TiO2-CuO-Mn2O3 / 2 25%‑30%, CuO3%‑10%, Mn2O 3 6%–20%, S 0.02%–0.1%, fly ash cenospheres 50%–60%; its specific gravity is 0.6–0.90 g / cm³. 3 Specific surface area is 10-50 m² 2 / g; possesses solid superacid properties with an acid strength H0 ≤ -14.5; dissolves in acidic solvents to generate trace amounts of copper and manganese ions. The catalyst of this invention can float on the surface of aqueous solutions, solving the problem of separating solid catalysts from insoluble p-hydroxybenzylhydantoin products; it catalyzes the synthesis of p-hydroxybenzylhydantoin via two pathways, achieving a product molar yield of 68%-72%; it possesses photocatalytic functionality, allowing for the regeneration of catalysts that have lost surface catalytic activity; and it reduces the generation of organic pollutants at the source.

A solid alumina composition is prepared from an acid-treated precursor composition, the precursor composition having an alumina hydroxide (Al(OH)3), aluminum oxyhydroxide (AlO(OH)), or a mixture thereof; where the solid alumina composition includes η-alumina characterized by having an X-ray powder diffraction pattern with peaks at 19.6±0.5° 2θ and 66.8±0.5° 2θ; and where the solid alumina composition has an acidity measured by an NH3-TPD test, characterized by: (1) an acid site density ranging from about 200 to 800 μmol / g; and / or (2) an acid strength distribution of: about 20%-70% weak acid sites (such as about 30-50%, about 30-40%, or about 35-40%), about 30%-80% medium acid sites (such as about 50-70%, about 60-70%, or about 60-65%), and about 0-20% strong acid sites (such as about 0-10%, about 0-5%, or about 0-2%).

The present invention provides a carboxylate carrier loaded with carboxylic acid, which is a free-flowing powder of a granular solid. The compound of the present invention is stable, biocompatible and digestible, facilitates high acid loading and controlled release of customizable acid strength in solution, and facilitates the handling of liquid carboxylic acids, such as formic acid, acetic acid, glycolic acid, propionic acid, butyric acid and lactic acid, in powder form. The compound of the present invention is soluble in polar solvents, except for the carrier component, which is thermally stable at up to 300°C. The present invention further provides a method for making the free-flowing compound of the present invention, which comprises loading the carrier carboxylic acid with at least one loaded carboxylic acid selected from preferably liquid short-chain carboxylic acids by contacting an alkaline earth metal base, a carrier carboxylic acid and a component of the loaded carboxylic acid. The powder product obtained by the method of the present invention has the characteristics of low moisture, a defined and uniform particle size, free flow and no agglomeration.

The present application discloses a method for synthesizing a high-silica mordenite zeolite molecular sieve with better accessibility of reactive sites and its application, belonging to the field of molecular sieves. A method for synthesizing a high-silica mordenite zeolite molecular sieve with better accessibility of reactive sites includes the following steps: S1, obtaining a silicon-boron precursor made from a mother liquor concentrate and a boron source; S2, obtaining an aluminum-containing alkaline solution; S3, hydrothermally crystallizing a mixture containing the silicon-boron precursor and the alkaline solution to obtain a product; S4, performing heat treatment and / or acid treatment on the above product under water vapor to obtain the high-silica mordenite zeolite molecular sieve. This method improves the acid strength and the proportion of 8-membered ring acids while making the low-temperature activity of the reaction better; the solid waste in the molecular sieve synthesis is greatly reduced; the sewage treatment cost in the large-scale production of the molecular sieve is reduced; the initial reaction temperature is significantly lower than the current one under the same conditions; the single-pass life of the catalyst can be greatly improved.

The invention discloses an application of a Bronsted-Lewis bifunctional acidic ionic liquid catalyst in catalyzing an alcohol amine solution to desorb CO2. The anion part of the ionic liquid is a transition metal compound, and the cation part is a sulfonic acid functionalized imidazole group. The preparation method of the catalyst comprises the following steps: dissolving an imidazole organic matter in an organic solvent at a certain temperature, continuously stirring, slowly dropwise adding a corresponding amount of sulfonyl compound, and reacting for a period of time to obtain a mixed solution A; decantation separation is conducted on A, and washing and drying are conducted to obtain sulfonic acid functionalized imidazolium salt B; and then, adding a corresponding amount of transition metal compound into B at a certain temperature, stirring for a certain time to obtain a mixture C, and drying the mixture C to obtain the product Bronsted-Lewis bifunctional acidic ionic liquid catalyst. The Bronsted-Lewis bifunctional acidic ionic liquid is used for catalyzing the CO2 desorption process of an alcohol amine-rich solution, and compared with a traditional solid acid catalyst, the catalyst has the advantages of being adjustable in acid strength, high in structure designability, good in catalytic effect and the like, and has important significance in the field of CO2 capture through a high-efficiency and low-energy-consumption alcohol amine method.

The invention discloses a device and a method for preparing a gradient acid strength carbon-based catalyst by regenerating inactivated activated carbon. The device comprises a charging hanging basket, a dipping device, a regeneration reactor, a condenser and a tail gas treatment device, the charging hanging basket is used for containing an inactivated activated carbon catalyst; the top of the dipping device is provided with an opening, an inner cavity is filled with deionized water and can contain a loading hanging basket, the top of an inner cavity of the regeneration reaction device can be opened and closed, water vapor is introduced into the inner cavity and can contain the loading hanging basket, and a plurality of microwave generators are arranged in an interlayer of the regeneration reaction device and used for emitting microwaves into the inner cavity of the regeneration reaction device; the inner cavity of the regeneration reaction device is sequentially connected with the condenser and the tail gas treatment device. According to the technical scheme, by means of the excellent wave absorbing property of deionized water, water molecules are induced to dissociate through microwaves to generate hydrogen protons and hydroxyl plasma free radicals, carbon sites on the surface are oxidized and dissociated under the high-temperature auxiliary effect, phosphoric acid active sites are released again, and a pore channel structure is remodeled.

To provide a faujasite-type zeolite having a reduced proportion of Bronsted acids with high acid strength.SOLUTION: A faujasite-type zeolite has: a molar ratio of SiO2 / Al2O3 in a range of 40 or more and 200 or less; a crystallinity in a range of 0.20 or more and 1.00 or less; a Bronsted acid amount in a range of 20 μmol / g or more and 400 μmol / g or less, as measured by pyridine-adsorbed FT-IR after evacuation at 150°C; and a proportion of the Bronsted acid amount, measured after evacuation at 450°C, of less than 65%, relative to the Bronsted acid amount measured after evacuation at 150°C.SELECTED DRAWING: None

The present disclosure provides a modified MWW molecular sieve and a preparation method thereof, a xylene isomerization catalyst and a preparation method and application thereof, the method synthesizes spherical MWW molecular sieve raw powder agglomerated by nano flake structure by using two structure directing agents, and hydrothermally treats the MWW molecular sieve raw powder by using an alkaline treatment agent, and acid-washes and modifies the MWW molecular sieve raw powder by using an acidic treatment agent, effectively adjusts the acid center distribution and the pore structure of the MWW molecular sieve raw powder, and the prepared xylene isomerization catalyst has optimized acid centers and acid strength and a suitable pore structure, when the xylene isomerization catalyst is used for xylene isomerization containing ethylbenzene, the selectivity to xylene can be improved, and the xylene isomerization catalyst also has high ethylbenzene conversion activity (i.e. ethylbenzene is converted into xylene) and ethylbenzene de-ethylation activity (i.e. ethylbenzene is de-ethylated and converted into benzene), and the xylene isomerization catalyst realizes high yield of xylene or benzene.

The invention discloses a rare earth metal doped ZSM-48 molecular sieve (H-M-ZSM-48), a preparation method and application thereof, and application of the rare earth metal doped ZSM-48 molecular sieve to improvement of the performance of the ZSM-48 molecular sieve. According to the present invention, the specific rare earth metal is introduced into the synthesis liquid during the ZSM-48 molecular sieve synthesis stage, the rare earth metal is doped in the ZSM-48 molecular sieve skeleton through the hydrothermal synthesis, the acidic sites of the molecular sieve are moderately reduced, the acidic site distribution of the molecular sieve is changed, and the rare earth metal doped H-M-ZSM-48 molecular sieve is prepared. Furthermore, the H-M-ZSM-48 molecular sieve doped with the rare earth metal is used as a carrier, and is used for a hydroisomerization reaction of long-chain n-alkanes after loading noble metal (such as platinum). Due to the low acid strength, the concentration of B acid sites and appropriate acid site distribution, the target product isoparaffin can be obtained with high activity and high selectivity, the generation of cracking products is inhibited, and the proportion of single-branched chain products is remarkably increased.

This invention relates to the field of catalysis, and discloses a bilayer gradient acidic core-shell molecular sieve catalyst, its preparation method, and its applications. The bilayer gradient acidic core-shell molecular sieve catalyst comprises a ZSM-11 core layer and a BEA shell layer covering its surface; the acid strength of the ZSM-11 core layer is 0.40–1.20 mmol / g, and its average thickness is 0.5–3 μm; the acid strength of the BEA shell layer is 0.10–0.40 mmol / g, and its average thickness is 20–300 nm. This catalyst possesses a bilayer gradient acidic core-shell structure. When applied to the catalytic synthesis of tert-butylamine from isobutylene or its precursors (alcohols / ethers), it can improve single-pass conversion while maintaining high selectivity, and significantly reduce the carbon deposition rate and bed pressure drop growth, achieving long-term stable operation.