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CN-121990591-A - Spherical nano ZSM-35 molecular sieve and preparation method and application thereof

CN121990591ACN 121990591 ACN121990591 ACN 121990591ACN-121990591-A

Abstract

The invention provides a spherical nano ZSM-35 molecular sieve, and a preparation method and application thereof. The spherical nanometer ZSM-35 molecular sieve is formed by self-assembling a plurality of long bar-shaped nanometer ZSM-35 molecular sieves, the grain size of the spherical nanometer ZSM-35 molecular sieve is 40-100 nm, and the length of the long bar-shaped nanometer ZSM-35 molecular sieve is preferably within 100 nm. The spherical nano ZSM-35 molecular sieve prepared by the preparation method has the advantages of smaller grain size, higher specific surface area and external specific surface area, high diffusion and high activity in catalysis, adsorption separation and other applications.

Inventors

  • CHEN LONG
  • LV JIANGANG
  • LIU BO
  • WANG YUNZHENG

Assignees

  • 中国石油化工股份有限公司
  • 中石化（上海）石油化工研究院有限公司

Dates

Publication Date
20260508
Application Date
20241107

Claims (10)

  1. 1. The spherical nanometer ZSM-35 molecular sieve is characterized by being formed by self-assembling a plurality of long bar-shaped nanometer ZSM-35 molecular sieves, the grain size of the spherical nanometer ZSM-35 molecular sieve is preferably 40-100 nm, and the length of the long bar-shaped nanometer ZSM-35 molecular sieve is preferably within 100 nm.
  2. 2. The spherical nano ZSM-35 molecular sieve according to claim 1, wherein the specific surface area of the spherical nano ZSM-35 molecular sieve is not less than 310m 2 ·g -1 , preferably 310-330 m 2 ·g -1 , and/or, The external specific surface area of the spherical nano ZSM-35 molecular sieve is not lower than 35m 2 ·g -1 , preferably 35-45 m 2 ·g -1 , and/or, The total pore volume of the spherical nano ZSM-35 molecular sieve is 0.15-0.25 cm 3 /g, and/or, The average pore diameter of the spherical nanometer ZSM-35 molecular sieve is 2-3nm.
  3. 3. A method for preparing a spherical nano ZSM-35 molecular sieve, comprising the following steps: and (3) carrying out crystallization reaction on the mixed solution containing the alkali source, the aluminum source, the silicon source, the template agent and the sodium oleate to obtain the spherical nano ZSM-35 molecular sieve.
  4. 4. A process according to claim 3, wherein the alkali source comprises an inorganic alkali source, preferably an alkali or alkaline earth hydroxide, more preferably one or more of sodium hydroxide, potassium hydroxide, magnesium hydroxide, and/or, The aluminum source comprises one or more of sodium aluminate, aluminum sulfate, aluminum chloride and aluminum nitrate, and/or, The silicon source comprises one or more of white carbon black, silica gel, silica sol and water glass, and/or, The template comprises an organic amine template, preferably cyclohexylamine and/or ethylenediamine.
  5. 5. The method according to claim 3 or 4, wherein the molar ratio of MxO to Al 2 O 3 in the mixed solution containing the alkali source, the aluminum source, the silicon source, the template agent and the sodium oleate is (1-2) 1, M represents an alkali metal or an alkaline earth metal, x is 1 or 2, and/or, The mole ratio of Al 2 O 3 to SiO 2 is 1 (20-35), and/or, The mole ratio of Al 2 O 3 to the template agent is 1 (4-8), and/or, The mole ratio of Al 2 O 3 to sodium oleate is 1 (0.05-0.2), and/or, The molar ratio of Al 2 O 3 to water is 1 (400-800).
  6. 6. The method according to any one of claims 3 to 5, wherein in the mixed solution containing the alkali source, the aluminum source, the silicon source, the template agent and sodium oleate, the molar ratio MxO: al 2 O 3 ：SiO 2 : the template agent: sodium oleate: water= (1 to 2): 1 (20 to 35): 4 to 8): 0.05 to 0.2): 400 to 800, M represents an alkali metal or alkaline earth metal, and x is1 or 2.
  7. 7. The method according to any of claims 3-6, wherein the crystallization temperature is 150-200 ℃, preferably 180-200 ℃, and/or the crystallization time is 36-96 h, preferably 48-72 h, and/or the crystallization is static crystallization.
  8. 8. The method according to any one of claims 3 to 7, wherein the mixed solution containing the alkali source, the aluminum source, the silicon source, the template agent and the sodium oleate is prepared by a method comprising the steps of: Mixing the alkali source, the aluminum source and the solvent, adding a template agent and sodium oleate, and then adding a silicon source to obtain a mixed solution containing the alkali source, the aluminum source, the silicon source, the template agent and sodium oleate; preferably, the temperature of the mixing is 10 ℃ to 80 ℃.
  9. 9. The method according to any one of claims 3 to 8, further comprising performing solid-liquid separation after crystallization reaction is completed to obtain a solid product, and washing, drying and roasting the solid product to obtain the spherical nano ZSM-35 molecular sieve; preferably, the drying temperature is 80-120 ℃; Preferably, the roasting temperature is 450-650 ℃.
  10. 10. Use of the spherical nano ZSM-35 molecular sieve according to claim 1 or 2, or the spherical nano ZSM-35 molecular sieve prepared by the method according to any one of claims 3 to 9, in catalyzing the carbonylation reaction of dimethyl ether; Preferably, the dimethyl ether carbonylation reaction comprises a reaction for preparing methyl acetate by carbonylation of dimethyl ether.

Description

Spherical nano ZSM-35 molecular sieve and preparation method and application thereof Technical Field The invention relates to the technical field of molecular sieves, in particular to a spherical nano ZSM-35 molecular sieve, and a preparation method and application thereof. Background In the middle and late 70 s of the last century, the company Mobil in the united states developed a molecular sieve with FER topology that had a vertically intersecting two-dimensional pore system in which the size of the ten-membered ring pore parallel to the [001] plane was 0.42×0.54nm and the size of the eight-membered ring pore parallel to the [010] plane was 0.35×0.48nm. ZSM-35 molecular sieve is widely used in catalytic reactions for hydrocarbon conversion, such as isomerization, polymerization, aromatization, cracking and other catalytic reactions of linear olefins. At present, the main synthesis method of the ZSM-35 molecular sieve is to rely on an organic template agent (common template agents include ethylenediamine, cyclohexylamine, n-butylamine, pyridine, pyrrolidine and the like) as the template agent, and the grain size of the molecular sieve is generally in a micron level. However, with the upgrading of the oil quality, the disadvantages of the molecular sieve with the micron-sized size are gradually displayed, such as larger diffusion resistance, easy coking and deactivation of the catalyst, and the like. While small-grained catalytic materials, particularly nano-sized molecular sieve catalysts, can effectively alleviate the above-mentioned problems. In general, the grain size of the nano-scale molecular sieve is within 100nm, and the nano-scale molecular sieve has small grain size, large specific surface area, increased exposed effective active sites, higher activity, shortened diffusion pore path, and better superiority for carbon deposition deactivation phenomenon caused by diffusion limitation. Compared with the synthesis of the conventional micron-sized ZSM-35 molecular sieve, the synthesis of the nano-sized ZSM-35 molecular sieve has higher difficulty, and the template agents such as the surfactant with high price and the like are often required to be used, so that the cost is high, and the filtration of the molecular sieve is also a great difficulty. If Hu et al, the Pi and TEAOH are utilized to synthesize the ZSM-35 molecular sieve (Designing ferrierite-based catalysts with improved properties for skeletal isomerization of n-butene to isobutene;Rsc Advances), with nano-plate stacking under dynamic conditions, the size of the obtained ZSM-35 molecular sieve nanocrystal is about 120nm long and 30nm thick. Although the molecular sieve with smaller grain size is synthesized, the crystallization temperature is low, the crystallization time is long, and the economic benefit is low, so that the current nano ZSM-35 molecular sieve has little application in industry. In the existing research report of preparing nano ZSM-35 molecular sieve, small-grain ZSM-35 molecular sieve is prepared mainly by adding organic surfactant and organic template agent, and the organic surfactant is expensive and has high difficulty in filtering and separating molecular sieve, so that the preparation cost is increased. The preparation of the nano ZSM-35 molecular sieve by using a simple and efficient synthesis method becomes a key point of industrial application. Disclosure of Invention In order to solve one of the technical problems in the prior art, the invention provides a spherical nano ZSM-35 molecular sieve, and a preparation method and application thereof. The first aspect of the invention provides a spherical nano ZSM-35 molecular sieve, wherein the spherical nano ZSM-35 molecular sieve is formed by self-assembling a plurality of long bar-shaped nano ZSM-35 molecular sieves. According to some embodiments of the invention, the spherical nano ZSM-35 molecular sieve has a grain size of 40-100 nm. According to some embodiments of the invention, the length of the elongated rod-shaped nano ZSM-35 molecular sieve is within 100nm. According to some embodiments of the invention, the spherical nano ZSM-35 molecular sieve has a crystallite size of 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm or any value therebetween. According to some embodiments of the invention, the length of the elongated rod-shaped nano ZSM-35 molecular sieve is 1nm, 5nm, 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm or any value in between. According to some embodiments of the invention, the specific surface area of the spherical nano ZSM-35 molecular sieve is not less than 310m 2·g-1, preferably 310-330 m 2·g-1. According to some embodiments of the invention, the external specific surface area of the spherical nano ZSM-35 molecular sieve is not less than 35m 2·g-1, preferably 35-45 m 2·g-1. According to some embodiments of the invention, the spherical nano ZSM-35 molecular sieve has a total pore volume of 0.15-0.25 cm 3/g. According to some embodiments