An alkyl transfer catalyst, its preparation method and application

Abstract

This invention discloses an alkyl transfer catalyst and its preparation method. The alkyl transfer catalyst contains a metal hydrogenation component, a modified Beta molecular sieve, and a binder. Based on the weight of the alkyl transfer catalyst, the content of the modified Beta molecular sieve is 30wt%~90wt%, and the content of the hydrogenation metal is 0.1wt%~5wt%. The ratio of acid content inside the micropores to acid content outside the micropores of the alkyl transfer catalyst is A. in / A out The concentration is 100-500, preferably 150-400, and more preferably 200-300. The method includes the preparation of a modified Beta molecular sieve and the preparation of a catalyst containing the modified Beta molecular sieve. The alkyl transfer catalyst, while improving xylene yield, can significantly reduce side reactions such as aromatic condensation carbon deposition and aromatic saturation, thus improving catalyst lifetime.

Description

Technical Field

[0001] This invention relates to the field of comprehensive utilization of aromatics, specifically to an alkyl transfer catalyst, its preparation method, and its application. Background Technology

[0002] Among benzene, toluene, xylene, and C9 aromatics, toluene and C9 aromatics have lower added value. In different processes, the content of toluene and C9 aromatics accounts for 40-50% of the total aromatic content. To fully utilize aromatic resources and increase product added value, toluene disproportionation and alkyl transfer technologies have been developed and are widely used in large-scale aromatics co-production plants.

[0003] Toluene disproportionation and alkyl transfer technology refers to the process of producing benzene and xylene from toluene and C9 aromatics in the presence of a fixed-bed reactor under a certain hydrogen pressure, with molecular sieves of MFI, MOR or BEA configuration and hydrogenated metals as the main components.

[0004] Japanese Patent Publication No. 51-29131 discloses a MoO3-NiO / Al2O3 toluene disproportionation and alkyl transfer catalyst, which can yield BTX mixed products under conditions such as 6 MPa and 550 °C.

[0005] US Patent 473028 discloses a toluene disproportionation and alkyl transfer catalyst, which uses mordenite as the acidic component and supports metals such as Ni, Pd, Ag, and Pt as the hydrogenation component. CN200610025095.8 discloses a toluene disproportionation and alkyl transfer catalyst, which contains 20-90 parts of hydrogen-form zeolite with a SiO2 / Al2O3 molar ratio of 10-100, 10-80 parts of binder, and 0.001-5 parts of platinum oxide.

[0006] The catalysts disclosed in the aforementioned patents have several problems, including numerous aromatic condensation side reactions, which lead to a decrease in xylene yield and significant carbon buildup, or numerous aromatic saturation side reactions and high aromatic loss rate. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides an alkyl transfer catalyst, its preparation method, and its applications. The alkyl transfer catalyst, while improving xylene yield, can significantly reduce side reactions such as aromatic condensation carbon deposition and aromatic saturation, thereby extending catalyst life.

[0008] The first aspect of this invention is to provide an alkyl transfer catalyst, wherein the alkyl transfer catalyst contains a metal hydrogenation component, a modified Beta molecular sieve, and a binder, wherein, based on the weight of the alkyl transfer catalyst, the content of the modified Beta molecular sieve is 30wt%~90wt%, the content of the hydrogenation metal is 0.1wt%~5wt%, and the ratio of the acid content inside the micropores to the acid content outside the micropores of the alkyl transfer catalyst is A.in / A out The value is 100~500, preferably 150~400, and even more preferably 200~300.

[0009] In the catalyst of this invention, the metal hydrogenation component can be a noble metal hydrogenation component or a non-noble metal hydrogenation component, preferably a non-noble metal hydrogenation component. The non-noble metal hydrogenation component is a metal of Group VIB and / or Group VIII, wherein the Group VIB metal is preferably molybdenum and / or tungsten, and the Group VIII metal is preferably cobalt and / or nickel.

[0010] In the catalyst of this invention, the ratio of micropore volume to mesopore volume (V) micro / V meso The value is 0.4~3, preferably 0.5~2.

[0011] In the catalyst of this invention, the total acid content to the molar ratio of the hydrogenated metal (A) total The value of ( / M) is 2~10, preferably 3~6.

[0012] A second aspect of this invention provides a method for preparing an alkyl transfer catalyst, the method comprising the preparation of a modified Beta molecular sieve and the preparation of a catalyst containing the modified Beta molecular sieve, wherein the method for preparing the modified Beta molecular sieve includes the following steps:

[0013] (1) The template agent-free Beta molecular sieve raw powder is treated with inorganic acid;

[0014] (2) The material obtained in step (1) is impregnated with a pore protection agent;

[0015] (3) The material obtained in step (2) is treated with macromolecular organic acids;

[0016] (4) The material obtained in step (3) is mixed with a dealuminizing and silicon-replenishing reagent for dealuminizing and silicon-replenishing, then washed, filtered, dried and calcined to obtain modified Beta molecular sieve;

[0017] Furthermore, in step (1), the Beta molecular sieve can be a commercially available product or a microporous hydrogen-type Beta molecular sieve prepared according to existing technology. The properties of the Beta molecular sieve are as follows: SiO2 / Al2O3 molar ratio 20~40.

[0018] In the method of the present invention, in step (1), the inorganic acid pore treatment process is as follows: the Beta molecular sieve is placed in an acidic solution, stirred, filtered, and this process is repeated 2 to 4 times; then it is washed with deionized water and dried.

[0019] Further, in step (1), the H of the inorganic acid solution +The concentration is 0.1~0.6 mol / L, preferably 0.2~0.4 mol / L.

[0020] Further, in step (1), the washing is performed 1 to 5 times until the content of inorganic acid anions is less than 0.1 wt%.

[0021] Further, in step (2), the pore protection solution is one or more of tetraethylammonium hydroxide solution, tetrapropylammonium hydroxide solution, etc. The concentration of the pore protection agent solution is 0.2~2.0 mol / L, preferably 0.4~1.5 mol / L.

[0022] Furthermore, in step (2), the impregnation is preferably an equal-volume impregnation. The impregnation treatment temperature is room temperature, generally 20~25℃.

[0023] Further, in step (3), the organic acid is one or more of 2,4-dimethylbenzenesulfonic acid and 2,5-dimethylbenzoic acid.

[0024] Further, in step (3), the specific operation is as follows: first, mix the material obtained in step (2) with water, wherein the liquid-solid ratio of water to the material obtained in step (2) is 2:1~6:1 mL / g, and then add organic acid until the pH value of the solution drops to 5~8, preferably 6.0~7.0.

[0025] Further, in step (4), the dealuminizing and silicon-replenishing reagent is at least one of ammonium hexafluorosilicate solution, tetraethyl orthosilicate solution, etc. The molar concentration of the dealuminizing and silicon-replenishing reagent is 0.3~1.0 mol / L. The mass ratio of the material obtained in step (3) to the dealuminizing and silicon-replenishing reagent is 1:1~1:5.

[0026] Further, the specific operation process of step (4) is as follows: rapidly heat the material obtained in step (3) to 60~100℃ and continuously stir, add the aluminum removal and silicon replenishment reagent dropwise, and continue stirring for 60~120min after the dropwise addition is completed. Among them, the dropwise addition rate does not exceed 0.5mL / min·g of the material obtained in step (3); preferably 0.2~0.4mL / min·g of the material obtained in step (3).

[0027] Furthermore, in step (4), the filtration and washing can be carried out using conventional methods in the art, the drying temperature is 100℃~150℃, the drying time is 2~4h, the calcination temperature is 400℃~600℃, and the calcination time is 3~5h.

[0028] Furthermore, the preparation process of the catalyst containing modified Beta molecular sieve involves mixing, extruding, and molding the modified molecular sieve, hydrogenated metal, and binder (preferably aluminum sol), followed by drying and calcination to obtain the catalyst containing modified Beta molecular sieve, which is an alkyl transfer catalyst.

[0029] Furthermore, the active metal is a metal of Group VIB and / or Group VIII, wherein the Group VIB metal is preferably molybdenum and / or tungsten, and the Group VIII metal is preferably cobalt and / or nickel.

[0030] A third aspect of the present invention provides the application of the above-described alkyl transfer catalyst in toluene disproportionation and alkyl transfer.

[0031] Compared with existing technologies, this alkyl transfer catalyst, its preparation method, and its application have the following advantages:

[0032] Through in-depth research, the inventors discovered that due to diffusion limitations, the toluene content within the Beta molecular sieve channels is high, leading to dominant reactions such as toluene disproportionation and toluene-to-trimethylyl transfer to xylene. Furthermore, the high enrichment of C9 aromatics outside the channels makes C9 aromatic disproportionation and aromatic condensation more likely, resulting in heavier aromatics and subsequent carbon deposition, causing catalyst deactivation. This invention reduces the total acid content through inorganic acid treatment while increasing the mesoporous content in the molecular sieve, improving feedstock diffusion and increasing the accessibility of acid centers to C9 aromatics. However, the expanded sieve contains more acid centers outside the channels, making it more susceptible to side reactions such as aromatic condensation. Therefore, this invention selectively masks acid centers on the outer surface of the Beta molecular sieve, enhancing toluene disproportionation and toluene / C9 aromatic alkyl transfer within the channels, while reducing C9 aromatic disproportionation and aromatic condensation reactions outside the channels. Based on this, a small amount of non-precious metal active centers are loaded to further reduce carbon deposition while avoiding aromatic saturation, thereby improving catalyst activity, xylene yield, and catalyst lifetime. Implementation

[0033] The following examples and comparative examples further illustrate the role and effect of the technical solution of the present invention, but the following examples do not constitute a limitation on the scope of protection of the present invention.

[0034] In this invention, unless otherwise specified, all percentages (%) in the embodiments and comparative examples refer to mass fractions.

[0035] In this invention, the total acid content is determined as follows: The powdered catalyst is compressed into tablets, evacuated, and then degassed at 450°C for 2 hours. After the temperature drops to room temperature, a pyridine molecule with a kinetic diameter of 5 Å is used as a probe molecule to measure the infrared spectrum of chemical desorption, and the adsorption amount is calculated. Since the diameter of the pyridine molecule is smaller than that of the molecular sieve pores, this method can obtain its total acid content A. total .

[0036] In this invention, the method for determining the acid content outside the micropore channels is as follows: The powdered catalyst is compressed into tablets, vacuumed, and then degassed at 450°C for 2 hours. After the temperature drops to room temperature, 2,6-di-tert-butylpyridine molecules are used as probe molecules to measure the infrared spectrum of its chemical desorption, and the adsorption amount is calculated. Since the diameter of 2,6-di-tert-butylpyridine molecules is larger than that of the molecular sieve channels, this method can obtain the acid content A outside the micropore channels. out .

[0037] The difference between the total acidity obtained from pyridine infrared spectroscopy and the acidity outside the micropores obtained from 2,6-di-tert-butylpyridine infrared spectroscopy is A. in。

[0038] In this invention, pore volume and micropore volume are determined by physical adsorption: an ASAP 2420 cryogenic liquid nitrogen physical adsorption instrument manufactured by Micrometics, USA, is used. Before measurement, the sample is first calcined at 550℃ for 4 hours to remove the template agent. During testing, the sample is pretreated at 300℃ for 3 hours, and then nitrogen is adsorbed at 77K for testing.

[0039] Example 1

[0040] Take 300g of commercially available hydrogen-type Beta molecular sieve raw powder, add it to 1800mL of 0.1mol / L hydrochloric acid solution, stir and heat to 60℃ and keep for 1h, filter while hot, add 2400mL of water to the filter cake, heat to 60℃ and keep for 20min, filter while hot, and dry the filter cake at 120℃ for 24h. The obtained material was impregnated with an equal volume of 2.0 mol / L tetraethylammonium hydroxide solution and allowed to stand for 10 min. 1700 mL of water was added, and 2,5-dibenzenesulfonic acid was added dropwise until the pH reached 8.0. The mixture was stirred and heated to 60°C. 300 mL of 0.3 mol / L ammonium hexafluorosilicate solution was added dropwise using a peristaltic pump at a rate of 0.2 mL / min·g. The temperature was maintained at 60°C with continuous stirring for 90 min. The mixture was then filtered while hot. 2400 mL of water was added to the filter cake, and the mixture was heated to 60°C and maintained for 20 min. The mixture was then filtered while hot, and the filter cake was dried at 120°C for 24 h. The dried product was then calcined at 550°C for 3 h. The resulting modified molecular sieve was named Beta-1. Beta-1, aluminum sol binder, and nickel nitrate were mixed evenly by crushing in a certain proportion, then extruded, dried, and calcined to obtain the alkyl transfer catalyst CAT-1. Its properties are as follows: the ratio of acid content inside the micropores to acid content outside the micropores (A in / A out The ratio of micropore volume to mesopore volume (V) is 132. micro / V meso The ratio of total acid content to the molar ratio of hydrogenated metal is 2.8, which is 2.8. totalThe content of modified Beta molecular sieve is 80 wt%, and the content of NiO is 0.3 wt%.

[0041] Example 2

[0042] Take 300g of commercially available hydrogen-type Beta molecular sieve raw powder, add it to 1800mL of 0.6mol / L hydrochloric acid solution, stir and heat to 60℃ and keep for 1h, filter while hot, add 2400mL of water to the filter cake, heat to 60℃ and keep for 20min, filter while hot, and dry the filter cake at 120℃ for 24h. The obtained material was impregnated with an equal volume of 2.0 mol / L tetraethylammonium hydroxide solution and allowed to stand for 10 min. 1700 mL of water was added, and 2,5-dibenzenesulfonic acid was added dropwise until the pH reached 5.0. The mixture was stirred and heated to 60 °C. 300 mL of 1.0 mol / L ammonium hexafluorosilicate solution was added dropwise using a peristaltic pump at a rate of 0.2 mL / min·g. The temperature was maintained at 60 °C with continuous stirring for 90 min. The mixture was then filtered while hot. 2400 mL of water was added to the filter cake, and the mixture was heated to 60 °C and maintained for 20 min. The mixture was then filtered while hot, and the filter cake was dried at 120 °C for 24 h. The dried product was then calcined at 550 °C for 3 h. The resulting modified molecular sieve was named Beta-2. Beta-2, alumina sol binder, and molybdenum oxide were mixed and ground in a specific ratio, then extruded, dried, and calcined to obtain the alkyl transfer catalyst support CAT-2. Its properties are as follows: the ratio of acid content inside the micropores to acid content outside the micropores (A in / A out The ratio of micropore volume to mesopore volume (V) is 110. micro / V meso The ratio of total acid content to the molar ratio of hydrogenated metal (A) is 0.42. total The content of modified Beta molecular sieve is 60wt%, and the content of MoO3 is 2wt%.

[0043] Example 3

[0044] Take 300g of commercially available hydrogen-type Beta molecular sieve raw powder, add it to 1800mL of 0.3mol / L hydrochloric acid solution, stir and heat to 60℃ and keep for 1h, filter while hot, add 2400mL of water to the filter cake, heat to 60℃ and keep for 20min, filter while hot, and dry the filter cake at 120℃ for 24h. The obtained material was impregnated with an equal volume of 2.0 mol / L tetraethylammonium hydroxide solution and allowed to stand for 10 min. 1700 mL of water was added, and 2,5-dibenzenesulfonic acid was added dropwise until the pH reached 6.5. The mixture was stirred and heated to 60 °C. 300 mL of 0.6 mol / L ammonium hexafluorosilicate solution was added dropwise using a peristaltic pump at a rate of 0.2 mL / min·g. The temperature was maintained at 60 °C with continuous stirring for 90 min. The mixture was then filtered while hot. 2400 mL of water was added to the filter cake, and the mixture was heated to 60 °C and maintained for 20 min. The mixture was then filtered while hot, and the filter cake was dried at 120 °C for 24 h. The dried product was then calcined at 550 °C for 3 h. The resulting modified molecular sieve was named Beta-3. Beta-3, aluminum sol binder, and nickel nitrate were mixed uniformly by crushing in a specific ratio, then extruded, dried, and calcined to obtain the alkyl transfer catalyst support CAT-3. Its properties are as follows: the ratio of acid content inside the micropores to acid content outside the micropores (A in / A out The value is 245, and the ratio of micropore volume to mesopore volume (V) is... micro / V meso The ratio of total acid content to the molar ratio of hydrogenated metal (A) is 1.2. total The content of modified Beta molecular sieve is 80 wt%, and the content of NiO is 1.5 wt%.

[0045] Example 4

[0046] Take 300g of commercially available hydrogen-type Beta molecular sieve raw powder, add it to 1800mL of 0.4mol / L hydrochloric acid solution, stir and heat to 60℃ and keep for 1h, filter while hot, add 2400mL of water to the filter cake, heat to 60℃ and keep for 20min, filter while hot, and dry the filter cake at 120℃ for 24h. The obtained material was impregnated with an equal volume of 2.0 mol / L tetraethylammonium hydroxide solution and allowed to stand for 10 min. 1700 mL of water was added, and 2,5-dibenzenesulfonic acid was added dropwise until the pH reached 7.0. The mixture was stirred and heated to 60 °C. 300 mL of 0.6 mol / L ammonium hexafluorosilicate solution was added dropwise using a peristaltic pump at a rate of 0.2 mL / min·g. The temperature was maintained at 60 °C with continuous stirring for 90 min. The mixture was then filtered while hot. 2400 mL of water was added to the filter cake, and the mixture was heated to 60 °C and maintained for 20 min. The mixture was then filtered while hot, and the filter cake was dried at 120 °C for 24 h. The dried product was then calcined at 550 °C for 3 h. The resulting modified molecular sieve was named Beta-4. Beta-4, alumina sol binder, nickel nitrate, and molybdenum oxide were mixed and ground in a specific ratio, then extruded, dried, and calcined to obtain the alkyl transfer catalyst support CAT-4. Its properties are as follows: the ratio of acid content inside the micropores to acid content outside the micropores (A in / A out The ratio of micropore volume to mesopore volume (V) is 279. micro / V meso The ratio of total acid content to the molar ratio of hydrogenated metal (A) is 0.8. total The content of modified Beta molecular sieve is 4.2, the content of NiO is 0.5 wt%, and the content of MoO3 is 1.0 wt%.

[0047] Example 5

[0048] Take 300g of commercially available hydrogen-type Beta molecular sieve raw powder, add it to 1800mL of 0.2mol / L hydrochloric acid solution, stir and heat to 60℃ and keep for 1h, filter while hot, add 2400mL of water to the filter cake, heat to 60℃ and keep for 20min, filter while hot, and dry the filter cake at 120℃ for 24h. The obtained material was impregnated with an equal volume of 2.0 mol / L tetraethylammonium hydroxide solution and allowed to stand for 10 min. 1700 mL of water was added, and 2,5-dibenzenesulfonic acid was added dropwise until the pH reached 7.0. The mixture was stirred and heated to 60 °C. 300 mL of 0.4 mol / L ammonium hexafluorosilicate solution was added dropwise using a peristaltic pump at a rate of 0.2 mL / min·g. The temperature was maintained at 60 °C with continuous stirring for 90 min. The mixture was then filtered while hot. 2400 mL of water was added to the filter cake, and the mixture was heated to 60 °C and maintained for 20 min. The mixture was then filtered while hot, and the filter cake was dried at 120 °C for 24 h. The dried product was then calcined at 550 °C for 3 h. The resulting modified molecular sieve was named Beta-5. Beta-5, alumina sol binder, and nickel nitrate were mixed uniformly by crushing in a specific ratio, then extruded, dried, and calcined to obtain the alkyl transfer catalyst support CAT-5. Its properties are as follows: the ratio of acid content inside the micropores to acid content outside the micropores (A in / A out The ratio of micropore volume to mesopore volume (V) is 209. micro / V meso The ratio of total acid content to the molar ratio of hydrogenated metal (A) is 1.8. total The content of modified Beta molecular sieve is 40 wt%, and the content of NiO is 0.3 wt%.

[0049] Example 6

[0050] Take 300g of commercially available hydrogen-type Beta molecular sieve raw powder, add it to 1800mL of 0.3mol / L hydrochloric acid solution, stir and heat to 60℃ and keep for 1h, filter while hot, add 2400mL of water to the filter cake, heat to 60℃ and keep for 20min, filter while hot, and dry the filter cake at 120℃ for 24h. The obtained material was impregnated with an equal volume of 2.0 mol / L tetraethylammonium hydroxide solution and allowed to stand for 10 min. 1700 mL of water was added, and 2,5-dibenzenesulfonic acid was added dropwise until the pH reached 6.0. The mixture was stirred and heated to 60 °C. 300 mL of 0.4 mol / L ammonium hexafluorosilicate solution was added dropwise using a peristaltic pump at a rate of 0.2 mL / min·g. The temperature was maintained at 60 °C with continuous stirring for 90 min. The mixture was then filtered while hot. 2400 mL of water was added to the filter cake, and the mixture was heated to 60 °C and maintained for 20 min. The mixture was then filtered while hot, and the filter cake was dried at 120 °C for 24 h. The dried product was then calcined at 550 °C for 3 h. The resulting modified molecular sieve was named Beta-4. Beta-6, alumina sol binder, and nickel nitrate were mixed uniformly by crushing in a specific ratio, then extruded, dried, and calcined to obtain the alkyl transfer catalyst support CAT-6. Its properties are as follows: the ratio of acid content inside the micropores to acid content outside the micropores (A in / A out The ratio of micropore volume to mesopore volume (V) is 287. micro / V meso The ratio of total acid content to the molar ratio of hydrogenated metal (A) is 0.9. total The content of modified Beta molecular sieve is 50 wt%, and the content of NiO is 0.3 wt%.

[0051] Example 7

[0052] Take 300g of commercially available hydrogen-type Beta molecular sieve raw powder, add it to 1800mL of 0.5mol / L hydrochloric acid solution, stir and heat to 60℃ and keep for 1h, filter while hot, add 2400mL of water to the filter cake, heat to 60℃ and keep for 20min, filter while hot, and dry the filter cake at 120℃ for 24h. The obtained material was impregnated with an equal volume of 2.0 mol / L tetraethylammonium hydroxide solution and allowed to stand for 10 min. 1700 mL of water was added, and 2,5-dibenzenesulfonic acid was added dropwise until the pH reached 6.5. The mixture was stirred and heated to 60 °C. 300 mL of 0.4 mol / L ammonium hexafluorosilicate solution was added dropwise using a peristaltic pump at a rate of 0.2 mL / min·g. The temperature was maintained at 60 °C with continuous stirring for 90 min. The mixture was filtered while hot, and 2400 mL of water was added to the filter cake. The mixture was heated to 60 °C and maintained for 20 min. The mixture was then filtered while hot, and the filter cake was dried at 120 °C for 24 h. The dried product was then calcined at 550 °C for 3 h. The resulting modified molecular sieve was named Beta-4. Beta-7, alumina sol binder, and nickel nitrate were mixed uniformly by crushing in a specific ratio, then extruded, dried, and calcined to obtain the alkyl transfer catalyst support CAT-7. Its properties are as follows: the ratio of acid content inside the micropores to acid content outside the micropores (A... in / A out The ratio of micropore volume to mesopore volume (V) is 215. micro / V meso The ratio of total acid content to the molar ratio of hydrogenated metal (A) is 0.8. total The content of modified Beta molecular sieve is 3.5, the content of NiO is 0.8 wt%.

[0053] Comparative Example 1

[0054] Commercially available hydrogen-type Beta molecular sieves, alumina sol binders, and nickel nitrate were mixed uniformly by crushing in a certain proportion, followed by extrusion, drying, and calcination to obtain the alkyl transfer catalyst support CAT-B1. Its properties are as follows: the ratio of acid content inside the micropores to acid content outside the micropores (A... in / A out The ratio of micropore volume to mesopore volume (V) is 53. micro / V meso The ratio of total acid content to the molar ratio of hydrogenated metal (A) is 4.2. total The content of modified Beta molecular sieve is 80 wt%, and the content of NiO is 0.3 wt%.

[0055] Comparative Example 2

[0056] 300g of commercially available hydrogen-type Beta molecular sieve powder was added to 1800mL of 0.1mol / L hydrochloric acid solution, stirred, and heated to 60℃ for 1h. The mixture was then filtered while hot. 2400mL of water was added to the resulting filter cake, and the mixture was heated to 60℃ for 20min. The mixture was then filtered while hot, and the filter cake was dried at 120℃ for 24h. The dried product was then calcined at 550℃ for 3h. The resulting modified molecular sieve was named Beta-B1. Beta-B1, alumina sol binder, and nickel nitrate were mixed evenly by pressing in a specific ratio, then extruded, dried, and calcined to obtain the alkyl transfer catalyst support CAT-B2. Its properties are as follows: the ratio of acid content inside the micropores to acid content outside the micropores (A... in / A out The ratio of micropore volume to mesopore volume (V) is 35. micro / V meso The ratio of total acid content to the molar ratio of hydrogenated metal is 2.8, which is 2.8. total The content of modified Beta molecular sieve is 50 wt%, and the content of NiO is 0.3 wt%.

[0057] Comparative Example 3

[0058] 300g of commercially available hydrogen-type Beta molecular sieve powder was impregnated with an equal volume of 2.0 mol / L tetraethylammonium hydroxide solution and allowed to stand for 10 min. 1700mL of water was added, and 2,5-dibenzenesulfonic acid was added dropwise until the pH reached 8.0. The mixture was stirred and heated to 60℃. 300mL of 0.3mol / L ammonium hexafluorosilicate solution was added dropwise using a peristaltic pump at a rate of 0.2mL / min·g. The temperature was maintained at 60℃ and stirring was continued for 90 min. The mixture was filtered while hot, and 2400mL of water was added to the resulting filter cake. The mixture was heated to 60℃ and maintained for 20 min. The mixture was then filtered while hot, and the filter cake was dried at 120℃ for 24 h. The dried product was then calcined at 550℃ for 3 h. The resulting modified molecular sieve was named Beta-1. Beta-1, alumina sol binder, and nickel nitrate were mixed evenly by crushing according to a specific ratio, and then extruded, dried, and calcined to obtain the alkyl transfer catalyst support CAT-1. Its properties are as follows: the ratio of acid content inside the micropores to acid content outside the micropores (A in / A out The ratio of micropore volume to mesopore volume (V) is 167. micro / V meso The ratio is 5.2, and the molar ratio of total acid content to hydrogenated metal (A) is 5.2. total The content of ( / M) is 15.9, the content of modified Beta molecular sieve is 80wt%, and the content of NiO is 0.3wt%.

[0059] Example 8

[0060] 10 g of catalyst CAT1 was reacted at a reaction temperature of 410 °C, a pressure of 1.2 MPa, and a WHSV of 3.0 h⁻¹. -1 When the hydrogen-to-hydrocarbon molar ratio is 2.0 and the toluene:trimethylbenzene ratio is 1:1 (mol), an alkyl transfer experiment was conducted for 160 h. The conversion rate of (toluene + trimethylbenzene) was 55.7 wt%, the xylene yield was 32.1 wt%, the aromatic loss rate was 0.2%, and the coking amount was 1.4 wt%.

[0061] Example 9

[0062] 10 g of catalyst CAT2 was reacted at a reaction temperature of 410 °C, a pressure of 1.2 MPa, and a WHSV of 3.0 h⁻¹. -1 When the hydrogen-to-hydrocarbon molar ratio is 2.0 and the toluene:trimethylbenzene ratio is 1:1 (mol), an alkyl transfer experiment was conducted for 160 h. The conversion rate of (toluene + trimethylbenzene) was 53.2 wt%, the xylene yield was 29.1 wt%, the aromatic loss rate was 1.0%, and the coking amount was 1.1 wt%.

[0063] Example 10

[0064] 10 g of catalyst CAT3 was reacted at a reaction temperature of 410 °C, a pressure of 1.2 MPa, and a WHSV of 3.0 h⁻¹. -1 When the hydrogen-to-hydrocarbon molar ratio is 2.0 and the toluene:trimethylbenzene ratio is 1:1 (mol), an alkyl transfer experiment is conducted for 160 h. The conversion rate of (toluene + trimethylbenzene) is 59.3 wt%, the xylene yield is 35.1 wt%, the aromatic loss rate is 0.1%, and the coking amount is 0.8 wt%.

[0065] Comparative Example 4

[0066] 10 g of catalyst CAT-B1 was reacted at a reaction temperature of 410 ℃, a pressure of 1.2 MPa, and a WHSV of 3.0 h⁻¹. -1 When the hydrogen-to-hydrocarbon molar ratio is 2.0 and the toluene:trimethylbenzene ratio is 1:1 (mol), an alkyl transfer experiment is conducted for 160 h. The conversion rate of (toluene + trimethylbenzene) is 41.6 wt%, the xylene yield is 25.1 wt%, the aromatic loss rate is 1.3%, and the coking amount is 5.5 wt%.

[0067] Comparative Example 5

[0068] 10 g of catalyst CAT-B2 was reacted at a reaction temperature of 410 ℃, a pressure of 1.2 MPa, and a WHSV of 3.0 h⁻¹. -1When the hydrogen-to-hydrocarbon molar ratio is 2.0 and the toluene:trimethylbenzene ratio is 1:1 (mol), an alkyl transfer experiment was conducted for 160 h. The conversion rate of (toluene + trimethylbenzene) was 37.6 wt%, the xylene yield was 22.5 wt%, the aromatic loss rate was 1.1%, and the coking amount was 3.7 wt%.

[0069] Comparative Example 6

[0070] 10g of catalyst CAT-B3 was reacted at a reaction temperature of 410 ℃, a pressure of 1.2 MPa, and a WHSV of 3.0 h⁻¹. -1 When the hydrogen-to-hydrocarbon molar ratio is 2.0 and the toluene:trimethylbenzene ratio is 1:1 (mol), an alkyl transfer experiment is conducted for 160 h. The conversion rate of (toluene + trimethylbenzene) is 25.6 wt%, the xylene yield is 13.6 wt%, the aromatic loss rate is 0.8%, and the coking amount is 1.5 wt%.

Claims

1. An alkyl transfer catalyst, characterized in that: The alkyl transfer catalyst contains a metal hydrogenation component, a modified Beta molecular sieve, and a binder. Based on the weight of the alkyl transfer catalyst, the content of the modified Beta molecular sieve is 30wt%~90wt%, the content of the metal hydrogenation component is 0.1wt%~5wt%, and the ratio A of the acid content inside the micropores to the acid content outside the micropores of the alkyl transfer catalyst is... in / A out The range is 100 to 500. The total acidity obtained from pyridine infrared spectroscopy and the acidity outside the micropores obtained from 2,6-di-tert-butylpyridine infrared spectroscopy (A) out The difference is A in ; The ratio of micropore volume to mesopore volume of the alkyl transfer catalyst, V micro / V meso It is 0.4~3; The molar ratio A of the total acidity of the alkyl transfer catalyst to the metal hydrogenation component total / M is 2~10.

2. The catalyst according to claim 1, characterized in that: The ratio A of the acid content inside the micropores of the alkyl transfer catalyst to the acid content outside the micropores is... in / A out The range is 150 to 400.

3. The catalyst according to claim 1, characterized in that: The ratio A of the acid content inside the micropores of the alkyl transfer catalyst to the acid content outside the micropores is... in / A out It is between 200 and 300.

4. The catalyst according to claim 1, characterized in that: The metal hydrogenation component can be either a noble metal hydrogenation component or a non-noble metal hydrogenation component.

5. The catalyst according to claim 4, characterized in that: The metal hydrogenation component is a non-precious metal hydrogenation component.

6. The catalyst according to claim 4, characterized in that: The non-precious metal hydrogenation component is a non-precious metal of Group VIB and / or Group VIII.

7. The catalyst according to claim 6, characterized in that: Group VIB metals are molybdenum and / or tungsten, and Group VIII metals are cobalt and / or nickel.

8. The catalyst according to claim 1, characterized in that: The ratio of micropore volume to mesopore volume of the alkyl transfer catalyst, V micro / V meso It is 0.5~2.

9. The catalyst according to claim 1, characterized in that: The molar ratio A of the total acidity of the alkyl transfer catalyst to the metal hydrogenation component total / M is 3~6.

10. A method for preparing the alkyl transfer catalyst according to any one of claims 1 to 9, characterized in that: The method includes the preparation of modified Beta molecular sieves and the preparation process of catalysts containing modified Beta molecular sieves, wherein the preparation method of modified Beta molecular sieves includes the following steps: (1) The Beta molecular sieve raw powder after template removal is treated with inorganic acid; (2) The material obtained in step (1) is impregnated with a channel protectant solution; (3) The material obtained in step (2) is treated with macromolecular organic acids; (4) The material obtained in step (3) is mixed with a dealuminizing and silicon-replenishing reagent for dealuminizing and silicon-replenishing, then washed, filtered, dried and calcined to obtain modified Beta molecular sieve; In step (2), the pore protection agent solution is tetraethylammonium hydroxide solution and / or tetrapropylammonium hydroxide solution.

11. The method according to claim 10, characterized in that: In step (1), the properties of the Beta molecular sieve are as follows: SiO2 / Al2O3 molar ratio 20~40.

12. The method according to claim 10, characterized in that: In step (1), the inorganic acid treatment process is as follows: Place the Beta molecular sieve in an inorganic acid solution, stir, filter, and repeat this process 2 to 4 times; then wash with deionized water and dry.

13. The method according to claim 12, characterized in that: In step (1), the H+ concentration of the inorganic acid solution is 0.1~0.6 mol / L.

14. The method according to claim 13, characterized in that: In step (1), the H+ concentration of the inorganic acid solution is 0.2~0.4 mol / L.

15. The method according to claim 12, characterized in that: In step (1), the washing is performed 1 to 5 times until the content of inorganic acid anions is less than 0.1 wt%.

16. The method according to claim 10, characterized in that: In step (2), the concentration of the pore protection agent solution is 0.2~2.0 mol / L.

17. The method according to claim 16, characterized in that: In step (2), the concentration of the pore protection agent solution is 0.4~1.5 mol / L.

18. The method according to claim 10, characterized in that: In step (2), the impregnation is an equal-volume impregnation, and the impregnation treatment temperature is room temperature.

19. The method according to claim 10, characterized in that: In step (3), the macromolecular organic acid is 2,4-dimethylbenzenesulfonic acid and / or 2,5-dimethylbenzoic acid.

20. The method according to claim 10, characterized in that: In step (3), the specific operation is as follows: first, mix the material obtained in step (2) with water, wherein the liquid-solid ratio of water to the material obtained in step (2) is 2:1~6:1 mL / g, and then add macromolecular organic acid until the pH value of the solution drops to 5~8.

21. The method according to claim 20, characterized in that: In step (3), add macromolecular organic acids until the pH of the solution drops to 6.0~7.

0.

22. The method according to claim 10, characterized in that: In step (4), the dealuminizing and silicon replenishing reagent is at least one of ammonium hexafluorosilicate solution and tetraethyl orthosilicate solution, and the molar concentration of the dealuminizing and silicon replenishing reagent is 0.3~1.0 mol / L, wherein the mass ratio of the material obtained in step (3) to the dealuminizing and silicon replenishing reagent is 1:1~1:

5.

23. The method according to claim 10, characterized in that: The specific operation process of step (4) is as follows: rapidly heat the material obtained in step (3) to 60~100℃ and continue stirring, add aluminum removal and silicon replenishment reagent dropwise, and continue stirring for 60~120min after the dropwise addition is completed; wherein, the dropwise addition speed does not exceed 0.5mL / min·g of the material obtained in step (3).

24. The method according to claim 23, characterized in that: In step (4), the dropping rate of the dealuminizing and silicon-replenishing reagent is 0.2~0.4 mL / min·g. The material obtained in step (3).

25. The method according to claim 10, characterized in that: In step (4), the filtration and washing are carried out using conventional methods in the art, the drying temperature is 100℃~150℃, the drying time is 2~4h, the calcination temperature is 400℃~600℃, and the calcination time is 3~5h.

26. The method according to claim 10, characterized in that: The preparation process of the modified Beta molecular sieve catalyst involves mixing, extruding, and molding the modified Beta molecular sieve, metal hydrogenation components, and binder, followed by drying and calcination to obtain the modified Beta molecular sieve catalyst, which is an alkyl transfer catalyst.

27. The use of an alkyl transfer catalyst according to any one of claims 1 to 9 in toluene disproportionation and alkyl transfer.