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CN-122010135-A - Composite molecular sieve of MFI configuration molecular sieve and MCM-41 molecular sieve, manufacturing method and application thereof

CN122010135ACN 122010135 ACN122010135 ACN 122010135ACN-122010135-A

Abstract

The invention relates to a composite molecular sieve of an MFI configuration molecular sieve and an MCM-41 molecular sieve, a manufacturing method thereof and application thereof in a cyclohexanone oxime gas-phase Beckmann rearrangement reaction. The method for manufacturing the composite molecular sieve comprises the steps of providing a first molecular sieve containing a first template agent, and then manufacturing a second molecular sieve in the presence of a second template agent and the first molecular sieve containing the first template agent to obtain the composite molecular sieve, wherein the first template agent and the second template agent are different in chemical structure, the first molecular sieve is an MFI configuration molecular sieve, and the second molecular sieve is an MCM-41 molecular sieve. The composite molecular sieve material has a stable structure, not only can keep the active site of the first molecular sieve, but also is beneficial to improving the diffusion efficiency of reactants and products by introducing a mesoporous pore canal structure, reduces the occurrence of polymerization reaction, and plays a role in improving the activity and stability of the cyclohexanone oxime gas-phase Beckmann rearrangement reaction.

Inventors

  • LI SIJIE
  • SONG ZHAOYANG
  • XU HUIQING
  • LIU QUANJIE
  • WANG YANG

Assignees

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

Dates

Publication Date
20260512
Application Date
20241111

Claims (19)

  1. 1. A method of making a composite molecular sieve comprising the steps of: 1) Providing a first molecular sieve comprising a first template (such as making the first molecular sieve comprising a first template in the presence of the first template), and then 2) Producing a second molecular sieve in the presence of a second template and the first molecular sieve comprising the first template to obtain the composite molecular sieve, Wherein the first template is chemically different from the second template and the first molecular sieve is an MFI configuration molecular sieve (preferably an S-1 molecular sieve) and the second molecular sieve is an MCM-41 molecular sieve (preferably an all-silicon MCM-41 molecular sieve).
  2. 2. The method according to claim 1, wherein in the step 1), a silicon source, an aluminum source, and, An alkali source and water, wherein the silicon source (in terms of SiO 2 ): the aluminum source (calculated as Al 2 O 3 ) the alkali source (calculated as OH -1 ) the first template R: water molar ratio is from SiO 2 :Al 2 O 3 :OH - :R:H 2 0=1:0 to 0.01:0 to 2:0.03 to 1:5 to 60 (preferably from SiO 2 :Al 2 O 3 :OH - :R:H 2 0=1:0:0 to 2:0.03 to 1:5 to 60) and/or in step 2) a silicon source is also present, an aluminum source, An alkali source and water, wherein the silicon source (calculated as SiO 2 ) is the aluminum source (calculated as Al 2 O 3 ) is the alkali source (calculated as OH -1 ) is the second template D is the molar ratio of SiO 2 : Al 2 O 3 :OH - :D:H 2 0=1:0-0.01:0.1-0.5:0.02-1:20-200 (preferably SiO 2 :Al 2 O 3 : OH - :D:H 2 0=1:0.1-0.3:0.03-1:20-200), and/or the mass ratio of the first molecular sieve comprising the first template to the silicon source (calculated as SiO 2 ) of step 2) is (20-50): 1 (preferably (25-50): 1), and/or the average particle size of the first molecular sieve comprising the first template is more than 85% by 60 mesh (preferably more than 90% by 100 mesh), and/or the free water content of the first molecular sieve comprising the first template is not more than 10wt% (preferably not more than 5 wt%), and/or the first template comprising the first template is preferably less than 5wt% (preferably less than 5 wt%), and/or the mass ratio of the first template comprising the first template is less than 60% by weight (preferably less than 5 wt%), and/or the total weight of the first template is less than 60% and/or the total weight of the first template is less than 20% and/or the weight of the second template is preferably less than 70% is less than 70% by weight of deionized water.
  3. 3. The method of manufacture of claim 1, wherein the first template and the second template are capable of forming hydrogen bonds or ionic bonds with each other in the presence of water, and/or the first template is capable of being used for synthesizing the first molecular sieve, and/or the first template is selected from at least one of ethylenediamine, triethanolamine, tetrapropylammonium hydroxide, n-butylamine, ethylamine, 1, 6-hexamethylenediamine, tripropylamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, preferably tetrapropylammonium hydroxide, and/or the second template is capable of being used for synthesizing the second molecular sieve, and/or the second template is selected from at least one of cetyltrimethylammonium bromide, dodecylprimary amine, alkyldimethylamine and dimeric quaternary ammonium ions, long chain quaternary ammonium bases or salts, preferably cetyltrimethylammonium bromide.
  4. 4. The manufacturing method of claim 1, wherein the step 1) comprises the steps of: 1-1) mixing a silicon source, an aluminum source, an alkali source, a first templating agent, and water to form a first mixture, 1-2) Crystallizing said first mixture to produce said first molecular sieve comprising a first templating agent, 1-3) Isolating the first molecular sieve comprising the first template (preferably, optionally after filtration, drying (particularly spray drying) the first molecular sieve comprising the first template).
  5. 5. The production process according to claim 4, wherein in step 1-2), the crystallization conditions include a crystallization pressure of normal pressure to system autogenous pressure, presence or absence of seed crystals, a crystallization temperature of 130-220 ℃ and preferably 150-180 ℃ and a crystallization time of 24-96 hours and preferably 24-72 hours, and/or in step 1-3), the drying conditions include a drying temperature of 60-120 ℃ and preferably 65-110 ℃ and a drying time of 5-20 hours and preferably 8-15 hours, and/or in step 1-3), the spray drying conditions include a solid content of 35-65%, an inlet air temperature of 150-250 ℃, an outlet air temperature of 80-150 ℃ and an air velocity of 300-1500m 3 /h, and/or further comprising pulverizing (such as grinding) the first molecular sieve containing the first template to an average particle size of 85% or more passing through 60 mesh and preferably 90% or more passing through 100 mesh after the step 1-3).
  6. 6. The method of manufacture of claim 1, excluding a step capable of removing a portion or all of the first template from the first molecular sieve comprising the first template, and/or, wherein the step 1) does not include a calcination step.
  7. 7. The manufacturing method of claim 1, wherein the step 2) comprises the steps of: 2-1) mixing a silicon source, an aluminum source, an alkali source, a second templating agent, and water to form a second mixture, 2-2) Mixing said first molecular sieve comprising a first templating agent with said second mixture to obtain a composite mixture, 2-3) Optionally drying said composite mixture, crystallizing said composite mixture to produce said composite molecular sieve, 2-4) Optionally washing and/or optionally filtering, and drying the composite molecular sieve.
  8. 8. The manufacturing process of claim 7, wherein in step 2-2) the first molecular sieve comprising the first template is finely divided (e.g., sprayed) with the second mixture, and/or in step 2-2) the morphological integrity (particularly the bulk structure or the pore structure) of the first molecular sieve comprising the first template is substantially maintained after the mixing.
  9. 9. The production process according to claim 7, wherein in step 2-3) the composite mixture is dried, the crystallization conditions include a crystallization pressure of from atmospheric pressure to system autogenous pressure, a mass ratio of dry gel powder to water of 1 (0.2-0.7), preferably 1 (0.3-0.5), and the upper and lower parts are placed together in a hydrothermal autoclave, two-stage crystallization is adopted, the first stage crystallization temperature is 80-120 ℃ and preferably 90-110 ℃, the crystallization time is 12-48 hours and preferably 12-24 hours, the second stage crystallization temperature is 130-190 ℃ and preferably 130-170 ℃, the crystallization time is 24-72 hours and preferably 24-48 hours, and/or the drying conditions include a drying temperature of 50-120 ℃ and preferably 50-110 ℃, a drying time of 0.1-20 hours and preferably 0.5-12 hours, and/or in step 2-4), the drying conditions include a drying temperature of 80-120 ℃ and preferably 85-110 ℃ and a drying time of 8-20 hours and preferably 8-15 hours.
  10. 10. The method of claim 7, further comprising the step of calcining the composite molecular sieve after the step 2-4), wherein the conditions of the calcining include a calcining temperature of 400-650 ℃ in an oxygen-containing atmosphere (preferably 450-600 ℃) and a calcining time of 4-20 hours (preferably 4-10 hours).
  11. 11. The manufacturing process of claim 1, wherein in step 1) the first molecular sieve comprising the first template is substantially not removed after manufacture and/or in step 2) the morphological integrity (in particular the bulk structure or the pore structure) of the first molecular sieve comprising the first template is substantially maintained under the manufacturing conditions of the second molecular sieve and/or in step 2) the second molecular sieve is grown in situ on the first molecular sieve comprising the first template.
  12. 12. A composite molecular sieve comprising a first molecular sieve and a second molecular sieve covering the surface of the first molecular sieve, wherein the first molecular sieve is a MFI configuration molecular sieve (preferably an S-1 molecular sieve), the second molecular sieve is an MCM-41 molecular sieve (preferably an all-silicon MCM-41 molecular sieve), and the mass ratio of the first molecular sieve to the second molecular sieve is (25-50): 1, preferably (30-50): 1.
  13. 13. The composite molecular sieve of claim 12, wherein the first molecular sieve has an average particle size of 85% or more passing 60 mesh (preferably 90% or more passing 100 mesh).
  14. 14. The composite molecular sieve of claim 12, wherein the first molecular sieve and the second molecular sieve are substantially interpenetrated, and/or the XRD spectrum of the composite molecular sieve is substantially the same as that of the first molecular sieve, and/or the composite molecular sieve has a bimodal pore distribution, and/or the pore distribution of the composite molecular sieve has a most probable pore size of 0.45-0.65nm (preferably about 0.55 nm) and 3-5nm (preferably 3.5-4.5 nm), respectively, and/or the pore of the most probable pore size of 0.45-0.65nm accounts for more than 70% of the total pore volume (preferably about 80%), and/or the BET specific surface area of the composite molecular sieve is 350-550m 2 /g (preferably 350-500m 2 /g), and the pore volume is 0.35-0.55ml/g (preferably 0.35-0.50 ml/g).
  15. 15. The composite molecular sieve of claim 12, producible according to the production method of any one of claims 1 to 11.
  16. 16. A cyclohexanone oxime gas-phase beckmann rearrangement catalyst obtainable by subjecting the composite molecular sieve of claim 12 to an ion exchange treatment.
  17. 17. The catalyst of claim 16, wherein the ion exchange treatment (single) conditions comprise an ammonium salt solution concentration of 1-2mol/L, a solid-liquid mass ratio of the composite molecular sieve to the ammonium salt solution of 1 (10-30), a reaction temperature of 60-100 ℃ and a reaction time of 1-3 hours.
  18. 18. A process for producing caprolactam, comprising the step of subjecting cyclohexanone oxime to Beckmann rearrangement in the presence of the catalyst for vapor phase Beckmann rearrangement of cyclohexanone oxime according to claim 16.
  19. 19. The production process according to claim 18, wherein the conditions for the vapor phase Beckmann rearrangement reaction include a cyclohexanone oxime-ethanol solution as a raw material, nitrogen as a carrier gas, a nitrogen flow rate of 30 to 50ml/min, a raw material gasification temperature of 250 to 350 ℃, a reaction temperature of 250 to 400 ℃, and a feed space velocity of 2 to 5h -1 .

Description

Composite molecular sieve of MFI configuration molecular sieve and MCM-41 molecular sieve, manufacturing method and application thereof Technical Field The invention belongs to the technical field of petrochemical industry, and particularly relates to a composite molecular sieve of an MFI configuration molecular sieve and an MCM-41 molecular sieve, a manufacturing method thereof and application of the composite molecular sieve in a cyclohexanone oxime gas-phase Beckmann rearrangement reaction. Background Caprolactam is an important organic chemical raw material and is mainly used for synthesizing nylon-6. Nylon-6 is a polymer with unique performance, is resistant to oil, heat and chemical corrosion, has strong wear resistance, and is widely used for producing various civil and industrial fibers, and plastic members and components of automobiles, ships, electronic and electric appliances, engineering machinery and daily-use consumer products. Along with the stable development of the economy in China, the demands of industries such as textile, automobile, electronics and traffic on nylon-6 are continuously improved. In recent years, nylon-6 polymerization devices in China keep a situation of positive expansion, and the consumption of caprolactam is gradually increased and the demand is also gradually increased. According to statistics, the nylon-6 productivity of China exceeds 350 ten thousand tons/year, and the development potential in the future is still very good. The production technology of caprolactam is mainly classified into a cyclohexanone oxime gas phase rearrangement technology and a liquid phase rearrangement technology. Compared with the traditional liquid-phase Beckmann rearrangement reaction of the cyclohexanone oxime catalyzed by fuming sulfuric acid, the gas-phase rearrangement is a brand new caprolactam production technology, and can complete the conversion process of the cyclohexanone oxime into caprolactam under the action of a solid acid catalyst. Compared with the liquid phase rearrangement technology, the gas phase rearrangement technology does not need fuming sulfuric acid, omits the process of neutralizing sulfuric acid with liquid ammonia, does not produce by-product ammonium sulfate, greatly reduces the consumption of liquid ammonia in the caprolactam production process, and avoids the problems of equipment corrosion, environmental pollution and the like. Since the cyclohexanone oxime vapor phase Beckmann rearrangement reaction is usually carried out at a high temperature of 300 ℃ and above, the weakly acidic active sites of the high-silicon or all-silicon molecular sieve can effectively catalyze the vapor phase Beckmann rearrangement reaction. However, the reactants and the products are easy to polymerize under the high temperature condition to cause coking, while the traditional molecular sieve is mostly of a microporous structure, has narrow and single pore channels and lower molecular diffusion efficiency, and the reactants and the products are difficult to diffuse to cause carbon deposition in the pore channels, so that the problems of reduced catalytic efficiency, faster catalyst deactivation and the like are caused. Therefore, improving the diffusion performance of the molecular sieve catalyst is a key to improving the vapor phase Beckmann rearrangement reaction performance of cyclohexanone oxime. A part of researches show that the mesoporous molecular sieve has large pore volume and specific surface area, uniform and adjustable pore diameter and is widely applied to the field of macromolecular catalysis, but the amorphous pore wall structure of the mesoporous molecular sieve leads to poor hydrothermal stability and low activity. The micro-mesoporous composite molecular sieve integrates the characteristics of the micro-porous molecular sieve and the mesoporous molecular sieve, has abundant acidic sites in the micro-porous molecular sieve, better hydrothermal stability, excellent diffusion performance and carbon deposition resistance of mesoporous materials, and is suitable for being applied to the cyclohexanone oxime gas-phase Beckmann rearrangement reaction. A synthetic method for preparing a composite molecular sieve of caprolactam is disclosed in CN102557064a, for example. Aging a solution mixture containing a silicon compound, water and a structure directing agent, mixing the obtained aged mixture containing crystals with another silicon compound, water and a structure directing agent, and performing hydrothermal synthesis reaction on the obtained mixture to obtain the all-silicon composite molecular sieve catalyst. The catalyst is applied to the cyclohexanone oxime gas phase rearrangement reaction after alkali treatment, the conversion rate of the cyclohexanone oxime can reach 99 percent, and the selectivity of caprolactam can reach more than 96 percent. CA104556085A discloses a method for synthesizing an all-silicon micro-mesoporous composite material. And mixing and ag