CN117800357B - IM-5 molecular sieve synthesis method and modification method - Google Patents

IM-5 molecular sieve synthesis method and modification method Download PDF

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CN117800357B
CN117800357B CN202410020790.3A CN202410020790A CN117800357B CN 117800357 B CN117800357 B CN 117800357B CN 202410020790 A CN202410020790 A CN 202410020790A CN 117800357 B CN117800357 B CN 117800357B
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molecular sieve
crystallization
modifying
synthesis method
acid
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CN117800357A (en
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李江成
李�昊
李聪
杨帆
汪翔
李晓东
张鹏
刘燕
李保珍
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Shaanxi Tanwei Rixin Chemical Co ltd
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    • B01J37/0009—Use of binding agents; Moulding; Pressing; Powdering; Granulating; Addition of materials ameliorating the mechanical properties of the product catalyst
    • B01J37/0018—Addition of a binding agent or of material, later completely removed among others as result of heat treatment, leaching or washing,(e.g. forming of pores; protective layer, desintegrating by heat)
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    • B01J37/30—Ion-exchange
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    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
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    • C07C2/86—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms by condensation between a hydrocarbon and a non-hydrocarbon
    • C07C2/862—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms by condensation between a hydrocarbon and a non-hydrocarbon the non-hydrocarbon contains only oxygen as hetero-atoms
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    • B01J2229/18—After treatment, characterised by the effect to be obtained to introduce other elements into or onto the molecular sieve itself
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Abstract

The invention relates to a synthesis method and a modification method of an IM-5 molecular sieve, comprising the following steps: and fully stirring and mixing the 1, 5-dibromopentane, N-methylpyrrolidine, an aluminum source, inorganic alkali, seed crystals, a silicon source and water, crystallizing, separating solid from liquid, drying and roasting to obtain the IM-5 molecular sieve. The method for synthesizing the IM-5 structure molecular sieve by using the mixture of 1, 5-dibromopentane and N-methylpyrrolidine as a template agent through an in-situ method is characterized in that in the preparation process of molecular sieve sol, a seed crystal method is added for assisting in synthesis, and a certain proportion of template raw materials are added to achieve the effect of synchronous synthesis of the template agent and the molecular sieve, so that the synthesis efficiency is improved.

Description

IM-5 molecular sieve synthesis method and modification method
Technical Field
The invention relates to the technical field of catalyst synthesis, in particular to a synthesis method and a modification method of an IM-5 molecular sieve.
Background
IM-5 is a two-dimensional 10-membered ring channel molecular sieve, but has a limited three-dimensional pore canal, a larger cross structure in the molecular sieve, can play a role similar to a cage in the reaction, provides a generating space for large-volume transition state molecules in a bimolecular reaction, and also maintains the long-range diffusion characteristic of a two-dimensional channel system, and a narrower ten-membered ring channel network has shape selectivity for reactant and product molecules. The IM-5 molecular sieve belongs to the IMF topology, each unit cell contains 864 atoms (288 silicon atoms and 576 oxygen atoms), the unit cell parameters are The framework density of the IM-5 molecular sieve is lower than ZSM-5, but the unit cell volume is much greater than ZSM-5.
In addition, the high stability, high hydrothermal stability and acid distribution of the IM-5 ensure that the IM-5 has excellent catalytic performance in a plurality of catalytic applications, and has potential application value in the aspects of isomerization, alkylation and catalytic cracking.
In 1998, patent WO98/17581 was first prepared by using pyrrolidine double quaternary ammonium salt template agent, using white carbon black, al (NO 3)3, naOH) as raw materials, and dynamically crystallizing for 14 days under hydrothermal condition to successfully synthesize IM-5 molecular sieve in 2002, literature (Journal of Catalysis,2002, 206 (1): 125-133) adds mineralizer NaBr as an additional Na source in a synthesis system, and hydrothermal crystallization is also successful in 10 days to synthesize IM-5 molecular sieve in 2003, literature (Journal ofCatalysis,2003, 215 (1): 151-170) reports that the synthesis condition of IM-5 is further optimized, siO 2/Al2O3 is between 15-120, naOH/SiO 2 can obtain IM-5 molecular sieve in 0.6-0.8 in 2012, literature (MATERIALS LETTERS,2012, 69:16-19) adds PEG (polyethylene glycol) and CTAB (cetyl trimethyl ammonium bromide) in initial sol for synthesizing IM-5, successfully synthesizes nano-level IM-5 molecular sieve, wherein the viscosity of PEG is increased, and crystal growth of CTAB is inhibited in 2012 is inhibited by adding CTAB in 2012 to a spherical form of 2012, and the hollow CTAB is well-248 in 2012.
In 2013, the literature (petroleum institute, petroleum processing), 2013, 29 (4): 569-576) reported that the addition of seed crystals effectively shortened crystallization time from 14 days to 6 days. The synthesis research of the IMF structure molecular sieve IM-5 reported in the current literature is not more, mainly uses the reference original patent, the required template agent is expensive, the synthesis process is complex, the synthesis period is long, the efficiency is low, the repeatability is poor, the impurity phase is easy to generate, and a large amount of reagents which harm the environment such as diethyl ether, a large amount of acetone and the like are required.
For example, chinese patent CN 103466652B discloses a method for synthesizing an IM-5 molecular sieve by an in-situ template agent, which comprises the steps of mixing a silicon source, an aluminum source, a template agent synthesis raw material, sodium bromide, sodium hydroxide and water to prepare a synthesis liquid for crystallization, wherein the ratio of the template agent raw material 1, 5-dibromopentane or 1, 6-dibromohexane, N-methylpyrrolidine to the silicon source is 0.05-1:0.1-1:1, the template agent is more in use amount and is not friendly to the environment; chinese patent CN 110407228B discloses a method for synthesizing an IM-5 molecular sieve by an in-situ template, which comprises the steps of pre-reacting two raw materials 1, 5-dibromopentane and N-methylpyrrolidine required by synthesizing an original template in a solvent, mixing a pre-reaction product with a silicon source, an aluminum source and the like, performing hydrothermal crystallization to obtain the molecular sieve, omitting complicated processes such as high-cost separation and purification of the original template MPPBr 2, and using water, alcohol, ketone, ether and ester as solvents in the pre-reaction process, and being not friendly to the environment; and the two-step method has more steps for synthesizing the molecular sieve in situ, and the process flow is complex.
Disclosure of Invention
The invention aims to solve the technical problems, and provides a method for synthesizing and modifying an IM-5 molecular sieve by one-step in-situ crystallization synthesis, which has the advantages of short process flow, less synthesis steps, low energy consumption, less template agent consumption and environmental friendliness.
In order to achieve the purpose, the invention adopts the following technical scheme that the method for synthesizing the IM-5 molecular sieve comprises the following steps:
and fully stirring and mixing 1, 5-Dibromopentane (DBP), N-methylpyrrolidine, an aluminum source, inorganic alkali, seed crystals, a silicon source and water, crystallizing, separating solid from liquid, drying and roasting to obtain the IM-5 molecular sieve.
Further, the molar ratio of the aluminum source, the silicon source, the 1, 5-Dibromopentane (DBP), the N-methylpyrrolidine, the inorganic base and the water is as follows: 0.008-0.05:1:0.03-0.15:0.05-0.32:0.3-0.8:20-50; the seed crystal accounts for 3-8% of the added mass of the silicon source.
Further, the method comprises the steps of:
Fully stirring and mixing 1, 5-Dibromopentane (DBP), N-methylpyrrolidine, an aluminum source, inorganic base, seed crystals, a silicon source and water to obtain an initial gel mixture;
adding the initial gel mixture into a crystallization kettle for further crystallization to obtain a crystallization product;
performing solid-liquid separation on the obtained crystallized product, and washing a solid-phase product obtained by the solid-liquid separation with deionized water to neutrality to obtain a neutral solid-phase product;
Drying the neutral solid phase product at 90-120 ℃, and then roasting at 400-700 ℃ to obtain the IM-5 molecular sieve.
Further, when the initial gel mixture is added into a crystallization kettle for crystallization, single-stage temperature crystallization is adopted, and the conditions of the single-stage temperature crystallization are as follows: crystallizing at 140-210 deg.c for 4-12d.
Further, when the initial gel mixture is added into a crystallization kettle for crystallization, the crystallization is carried out by adopting two-stage temperature crystallization, wherein the two-stage temperature crystallization comprises a first-stage temperature crystallization and a second-stage temperature crystallization, and the conditions of the first-stage temperature crystallization are as follows: crystallizing at 130-170 deg.c for 1-5d; the crystallization conditions at the second stage temperature are as follows: crystallizing at 170-200deg.C for 1-7d.
Further, the silicon source is at least one selected from the group consisting of silica sol, activated silica, solid silica gel, silicon-containing compound, and white carbon black.
Further, the aluminum source includes at least one of aluminum salt, pseudo-boehmite, aluminum isopropoxide, aluminum hydroxide dry gel and activated alumina.
Further, the inorganic base is at least one selected from sodium hydroxide, potassium hydroxide, sodium oxide, potassium oxide, sodium carbonate and potassium carbonate.
Further, the seed crystal is Na-type IM-5 molecular sieve with template agent removed, and the relative crystallinity is 85%.
A method for modifying an IM-5 molecular sieve comprising:
Step a, carrying out ammonium exchange treatment on the obtained IM-5 molecular sieve and ammonium salt to obtain an ammonium exchange molecular sieve;
Step b, performing high-temperature roasting treatment on the ammonium exchange molecular sieve to remove the organic amine template agent, thereby obtaining an H-type molecular sieve;
Step c, dealuminating the H-type molecular sieve to obtain a dealuminated molecular sieve;
step d, washing and drying the obtained dealuminated molecular sieve, mixing the dealuminated molecular sieve with 1, 5-Dibromopentane (DBP), N-methylpyrrolidine, water and load metal, crystallizing the mixture, and obtaining slurry for secondary cleaning;
And e, repeating the step a and the step b on the molecular sieve after the secondary cleaning and drying to obtain the modified IM-5 molecular sieve.
Further, the conditions for carrying out the ammonium exchange treatment on the IM-5 molecular sieve and the ammonium salt in the step a are as follows: the weight ratio of the IM-5 molecular sieve to the ammonium salt to the water is as follows: 1:0.1-1:5-10; the temperature is between room temperature and 100 ℃ and the time is between 0.2 and 4 hours.
In the step c, dealuminizing the H-type molecular sieve by acid treatment, wherein the acid adopts one or more of hydrochloric acid, nitric acid, sulfuric acid, citric acid and hydrofluoric acid, and the concentration range of the acid is as follows: 4-12mol/L, wherein the treatment temperature is 50-100 ℃ and the treatment time is 2-24h when the acid treatment is carried out; the silicon-aluminum ratio of the dealuminated molecular sieve after the acid treatment is 220-500:1.
Further, in the step d, the mol ratio of the dealuminated molecular sieve, the 1, 5-Dibromopentane (DBP), the N-methylpyrrolidine and the water is 1:0.015-0.05:0.04-0.12:5-30; the content of the load metal is 0.1-5wt%.
Further, the load metal is selected from one or more of magnesium, calcium, barium, scandium, titanium, vanadium, chromium, nickel, copper, zinc and tungsten.
The beneficial effects of the invention are as follows:
1. The method for synthesizing the IM-5 molecular sieve by using the mixture of 1, 5-Dibromopentane (DBP) and N-methylpyrrolidine (NMP) as a template agent through an in-situ method is obtained, namely, in the preparation process of molecular sieve sol, a certain proportion of template raw materials are added to achieve the effect of synchronous synthesis of the template agent and the molecular sieve, so that the synthesis efficiency is improved.
2. The original template MPPBr 2 is not needed to be added in the synthesis process, the process of synthesizing the original template MPPBr 2 is omitted, complicated processes such as separation and purification are reduced, the synthesis cost is reduced, and the production process is more environment-friendly.
3. The method for obtaining the crystal-assisted synthesis of the IM-5 molecular sieve has the advantages that more crystal fragments and secondary structural units can be provided by adding the crystal seeds, the rapid nucleation of a crystallization system is promoted, more crystal nuclei are formed by the system, the IM-5 molecular sieve is generated in a guiding way, the generation of hetero-crystalline phases is reduced, the crystallinity is improved, the crystal growth time is correspondingly shortened, the use amount of a template agent is reduced, and the environmental pollution is reduced.
4. The prepared molecular sieve has the characteristics of high crystallinity and regular morphology.
5. The prepared IM-5 molecular sieve and the metal supported catalyst thereof have certain catalytic application prospects in the processes of n-butene, pentene isomerization, toluene methanol alkylation reaction and the like.
Drawings
FIG. 1 is an XRD spectrum of a molecular sieve sample synthesized in an example of the present invention;
FIG. 2 is an SEM photograph of a molecular sieve sample synthesized in an inventive example;
Detailed Description
The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.
Technical terms in the present invention, from which definitions are given, are understood in a normal meaning in the art without giving definitions.
The templating agent of the present invention is also known in the art as a structure directing agent or an organic structure directing agent.
A method for synthesizing an IM-5 molecular sieve comprises the following steps:
And fully stirring and mixing 1, 5-Dibromopentane (DBP), N-methylpyrrolidine, an aluminum source, inorganic alkali, seed crystals, a silicon source and water, crystallizing, separating solid from liquid, drying and sintering to obtain the IM-5 molecular sieve.
The mixture of 1, 5-Dibromopentane (DBP) and N-methylpyrrolidine (NMP) is added into a synthesis system as an in-situ template agent to be directly synthesized by a one-step method, so that the addition amount of the template agent 1, 5-bis (N-methylpyrrolidine) pentane bromide (MPPBr 2) is reduced, the cost is reduced, and compared with the conventional IM-5 molecular sieve synthesis, the steps of synthesizing and purifying the 1, 5-bis (N-methylpyrrolidine) pentane bromide (MPPBr 2) are reduced.
Wherein the synthesis is specifically as follows:
the molar ratio of the aluminum source to the silicon source to the template agent R1 to the template agent R2 to the inorganic alkali to the water is 0.008-0.05:1:0.05-0.32:0.03-0.15:0.3-0.8:20-50, the template agent R1 and the template agent R2 are preferably 0.07-0.15:0.03-0.07, wherein the adding amount of the seed crystal is 3-8% of the mass of the silicon source based on the mass of the silicon source;
wherein: the template agent R1 is N-methylpyrrolidine; the template agent R2 is 1, 5-Dibromopentane (DBP).
The aluminum source is at least one of aluminum salt, pseudo-boehmite, aluminum isopropoxide, aluminum hydroxide gel and active alumina; the aluminum salt is preferably at least one of aluminum chloride, aluminum nitrate and aluminum sulfate.
The silicon source is at least one selected from silica sol, active silica, solid silica gel, silicon-containing compound shown in formula I and white carbon black.
In formula I, R 1、R2、R3 and R 4 are each alkyl groups of C 1-C4, such as methyl, ethyl, propyl and isomers thereof and butyl and isomers thereof.
The inorganic base is at least one selected from sodium hydroxide, potassium hydroxide, sodium oxide, potassium oxide, sodium carbonate and potassium carbonate.
The seed crystal is Na-type IM-5 molecular sieve for removing the template agent.
During synthesis, the method comprises the following steps:
Fully mixing and stirring an aluminum source, a silicon source, a template agent R1, a template agent R2, inorganic alkali and water to prepare an initial gel mixture, wherein the molar ratio of the aluminum source to the silicon source to the template agent R2 is 0.008-0.05:1:0.05-0.32:0.03-0.15:0.3-0.8:20-50, the template agent R1 and the template agent R2 are preferably 0.07-0.15:0.03-0.07, and the seed crystal is 3-8% of the addition amount of the silicon source;
Placing the prepared initial gel mixture into a crystallization kettle for crystallization, and crystallizing the initial gel mixture for 4-12d at a single-stage temperature of 140-210 ℃ in the crystallization kettle during crystallization; the preferred single-stage temperature is 160-180deg.C for crystallization for 5-9d.
When the initial gel mixture is crystallized in the crystallization kettle, the crystallization can be carried out by adopting single-stage temperature or adopting two-end temperature change; the crystallization temperature of the first stage is lower than that of the second stage, and the crystallization conditions of each stage are respectively and independently: the first stage of crystallization is carried out under autogenous pressure at 130-170 ℃ for 1-5d, and the second stage of crystallization is carried out under autogenous pressure at 170-200 ℃ for 1-7d; preferably, the first stage of crystallization is carried out under autogenous pressure at 140-165 ℃ for 2-4d, and the second stage of crystallization is carried out under autogenous pressure at 170-185 ℃ for 2-5d.
After crystallization is completed, performing solid-liquid separation on the obtained crystallized product, and washing a solid-phase product obtained by the solid-liquid separation with deionized water to neutrality to obtain a neutral solid-phase product;
Drying the neutral solid phase product at 90-120 ℃, and then roasting at 400-700 ℃ to obtain the IM-5 molecular sieve.
The embodiment provides a method for modifying an IM-5 molecular sieve:
step a, carrying out ammonium exchange treatment on the obtained IM-5 molecular sieve (Na-type molecular sieve is also called water washing molecular sieve) and ammonium salt to obtain an ammonium exchange molecular sieve;
B, performing high-temperature roasting treatment on the ammonium exchange molecular sieve obtained in the step a, and removing the organic amine template agent to obtain an H-type molecular sieve;
step c, dealuminating the H-type molecular sieve obtained in the step b through acid treatment to obtain a high silica alumina ratio molecular sieve (also called dealuminated molecular sieve);
Step d, washing the molecular sieve with the high silicon-aluminum ratio obtained in the step c by deionized water until the pH value is=6.0-7.0, mixing the molecular sieve with a mixed template agent, water and 0.1-5wt% of load metal, performing a second crystallization step, and performing second cleaning and drying on the obtained slurry;
Step e, carrying out a second ammonium exchange step and a second roasting step on the molecular sieve after the second cleaning and drying to obtain a modified IM-5 molecular sieve, namely a catalyst; the second ammonium exchange step is the same as the process of step a; the second calcination step is identical to the process of step b.
The silicon-aluminum ratio of the prepared modified IM-5 molecular sieve catalyst is 150-270:1, in the step d, the load metal is selected from one or more of magnesium, calcium, barium, scandium, titanium, vanadium, chromium, nickel, copper, zinc and tungsten; the content of the supported metal is 0.1-5wt%, calculated as the oxide of the supported metal and based on the dry weight of the molecular sieve.
The ammonium salt in the step a is one or more of ammonium chloride, ammonium sulfate and ammonium nitrate; the ammonium exchange condition is that the weight ratio of molecular sieve, ammonium salt and water is 1:0.1-1:5-10 based on dry weight, the temperature is room temperature to 100 ℃ and the time is 0.2-4 hours; the sodium content of the ammonium exchange molecular sieve is less than 0.2 wt.% based on the total dry weight of the ammonium exchange molecular sieve and calculated as sodium oxide.
The acid in the acid treatment process in the step c is selected from one or more of hydrochloric acid, nitric acid, sulfuric acid, citric acid and hydrofluoric acid; the concentration range of the acid is 4-12mol/L, the volume ratio of the molecular sieve to the acid is 1:5-20 based on the dry weight, the acid treatment temperature is 50-100 ℃, and the treatment time is 2-24h; the silicon-aluminum ratio of the dealuminated molecular sieve after the acid treatment is 220-500:1.
In the step d, the secondary crystallization adopts a mixed template agent comprising a template agent R1 and a template agent R2; the template agent R1 is N-methylpyrrolidine (NMP); template R2 is 1, 5-Dibromopentane (DBP); the mol ratio of the dealuminated molecular sieve to the template agent R1 to the template agent R2 to the water is 1:0.04-0.12:0.015-0.05:5-30.
The crystallization process can be carried out at a single-stage temperature, and generally, the crystallization is carried out for 4-12 days under autogenous pressure and at 140-210 ℃; preferably, the crystallization is performed under autogenous pressure at 160-180deg.C for 5-9d.
The crystallization process can also adopt two-stage variable-temperature crystallization, namely, the crystallization process comprises a first-stage crystallization and a second-stage crystallization, wherein the crystallization temperature of the first-stage crystallization is lower than that of the second-stage crystallization in the normal condition, and the crystallization conditions of the respective stages are respectively and independently: the first stage of crystallization is carried out under autogenous pressure at 130-170 ℃ for 1-5d, and the second stage of crystallization is carried out under autogenous pressure at 170-200 ℃ for 1-7d; preferably, the first stage of crystallization is carried out under autogenous pressure at 140-165 ℃ for 2-4d, and the second stage of crystallization is carried out under autogenous pressure at 170-185 ℃ for 2-5d.
The solid phase obtained by solid-liquid separation and water washing of the mixture obtained by crystallization in this example may be dried and optionally calcined under conventional conditions to obtain a molecular sieve. In the present invention, "optional" means optional and may be understood as comprising or not comprising. Specifically, the drying conditions may be carried out at a temperature of 90 to 120 ℃, and the drying time may be selected according to the drying temperature, and may be generally 6 to 14 hours. The purpose of calcination is mainly to remove the template agent remained in the molecular sieve pore canal in the molecular sieve synthesis process, and whether the calcination is carried out can be determined according to specific use requirements. The calcination is preferably performed after the completion of the drying. The high temperature firing conditions are conducted at a temperature of 400 to 700 ℃, and the duration of firing may be selected depending on the firing temperature, and may be generally 3 to 6 hours. Calcination is generally carried out in an air atmosphere. In addition, the solid phase obtained by solid-liquid separation is washed before drying, namely, the crystallization product obtained by hydrothermal crystallization is subjected to solid-liquid separation, washed to be neutral by deionized water and dried, so that molecular sieve raw powder can be obtained; or carrying out solid-liquid separation on a crystallization product obtained by hydrothermal crystallization, washing to be neutral by deionized water, drying and roasting to obtain the sodium molecular sieve after roasting. The solid-liquid separation method may be carried out by conventional methods such as filtration, centrifugal separation, etc.
In this embodiment, the heating mode of any step in the IM-5 molecular sieve synthesis and modification method is not particularly limited, and a temperature programming mode, for example, 0.5-5 ℃/min, may be adopted.
In this embodiment, the crystallization process pressure in the synthesis and modification method of the IM-5 molecular sieve is not particularly limited, and may be the autogenous pressure of the crystallization system.
In the embodiment, crystallization in the method for synthesizing and modifying the IM-5 molecular sieve is carried out in a closed environment, and a reaction vessel for carrying out crystallization is a stainless steel reaction kettle with a polytetrafluoroethylene lining.
After the preparation of the molecular sieve is finished, various indexes such as physics, chemistry and the like of the molecular sieve are characterized, and the molecular sieve mainly comprises: the n (SiO 2)/n(Al2O3), namely the silicon-aluminum ratio, is calculated by the content of the silicon oxide and the aluminum oxide, and the content of the silicon oxide and the aluminum oxide is measured by adopting a GB/T30905-2014 standard method.
Calculation of the relative crystallinity of the IM-5 molecular sieve, taking a certain molecular sieve as a reference (the crystallinity is defined as 100 percent), and selecting the ratio of the sum of peak areas of 5 peaks of a sample in a range of 22-26 degrees 2 theta to the sum of 5 peak areas corresponding to the molecular sieve reference.
The content of the supported metal in this example was determined by using the GB/T30905-2014 standard method.
The sodium content in this example was determined using the GB/T30905-2014 standard method.
The synthesis method and the modification method of the IM-5 molecular sieve in the invention are illustrated in detail by specific examples.
In the following examples, X-ray powder diffraction phase analysis and scanning electron microscope morphology analysis were used in the analysis of the as-produced IM-5 molecular sieves; wherein the X-ray powder diffraction phase analysis (XRD) employed an Empyrean type diffractometer of the family pananaceae, netherlands, which was equipped with a PIXcel 3D detector. Test conditions: cu target, K alpha radiation, ni filter, tube voltage 40kV, tube current 40mA and scanning range 5-50 degrees.
Scanning electron microscope morphology analysis (SEM) a japanese scanning electron microscope type S4800. Test conditions: after the sample is dried and ground, it is stuck on the conductive adhesive. The accelerating voltage of the analysis electron microscope is 5.0kV, and the magnification is 20-800000 times.
Example 1
A synthesis method of an IM-5 molecular sieve comprises the following steps:
0.12 g of pseudo-boehmite (Al 2O3 mass fraction 83%) and 28.64 g of deionized water are stirred and mixed until uniform, 1.15 g of sodium hydroxide (NaOH mass fraction 97%), 10.44 g of template agent R (N-methylpyrrolidine (NMP) mass fraction 99%), 0.57 g of template agent R (1, 5-Dibromopentane (DBP) mass fraction 97%), 0.16 g of seed crystal and 2.58 g of solid silica gel (SiO 2 mass fraction 93%) are added in sequence under stirring, and the mixture is stirred thoroughly.
Covering a polytetrafluoroethylene lining filled with the reaction mixture, putting the polytetrafluoroethylene lining into a stainless steel autoclave for sealing, putting the autoclave into a rotary convection oven, setting the rotating speed to be 20r/min, and carrying out single-stage crystallization under autogenous pressure: crystallizing at 170deg.C for 7d, taking out crystallized product when the temperature of autoclave is reduced to room temperature, filtering or centrifuging, washing the obtained solid phase with deionized water to neutrality, and drying at 110deg.C for 12 hr to obtain molecular sieve raw powder.
The obtained molecular sieve is subjected to X-ray diffraction analysis, an XRD spectrum is shown in figure 1, and the pure-phase IM-5 molecular sieve is proved to have the relative crystallinity of 105 percent. The morphology of the molecular sieve was observed by SEM, and the SEM photograph is shown in fig. 2, and is in a flat plate shape.
Example 2
A synthesis method of an IM-5 molecular sieve comprises the following steps:
0.05 g of aluminum hydroxide dry gel (Al 2O3 mass percent 75%) and 21.44 g of deionized water are stirred and mixed until uniform, and 0.99 g of sodium hydroxide (NaOH mass percent 97%), 10.76 g of template agent R (N-methylpyrrolidine (NMP) mass percent 99%), 20.95 g of template agent R (1, 5-Dibromopentane (DBP) mass percent 97%), 0.08 g of seed crystal and 2.58 g of solid silica gel (SiO 2 mass percent 93%) are sequentially added under stirring and fully stirred until uniform.
Covering a polytetrafluoroethylene lining filled with the reaction mixture, putting the polytetrafluoroethylene lining into a stainless steel autoclave for sealing, putting the autoclave into a rotary convection oven, setting the rotating speed to be 20r/min, and carrying out first-stage crystallization under autogenous pressure: crystallizing for 3d at 150 ℃, then heating to 180 ℃ for second-stage crystallization: crystallizing at 180 deg.c for 3d, filtering or centrifuging to obtain solid phase, washing the solid phase with deionized water to neutrality, and drying at 100 deg.c for 12 hr to obtain molecular sieve powder.
Example 3
A synthesis method of an IM-5 molecular sieve comprises the following steps:
0.07 g of pseudo-boehmite (Al 2O3 mass fraction 83%) and 25.04 g of deionized water are stirred and mixed until uniformity, 1.22 g of sodium hydroxide (NaOH mass fraction 97%), 0.80 g of template R (N-methylpyrrolidine (NMP) mass fraction 99%), 20.95 g of template R (1, 5-Dibromopentane (DBP) mass fraction 97%), 0.10 g of seed crystal and 2.58 g of solid silica gel (SiO 2 mass fraction 93%) are added in sequence under stirring, and the mixture is stirred thoroughly.
Covering a polytetrafluoroethylene lining filled with the reaction mixture, putting the polytetrafluoroethylene lining into a stainless steel autoclave for sealing, putting the autoclave into a rotary convection oven, setting the rotating speed to be 20r/min, and carrying out first-stage crystallization under autogenous pressure: crystallizing for 2d at 160 ℃, then heating to 180 ℃ for second-stage crystallization: crystallizing at 180 deg.c for 4d, filtering or centrifuging to obtain solid phase, washing the solid phase with deionized water to neutrality, and drying at 100 deg.c for 12 hr to obtain molecular sieve powder.
Example 4
A synthesis method of an IM-5 molecular sieve comprises the following steps:
0.10 g of active alumina (Al 2O3 mass fraction 98%) and 28.70 g of deionized water are stirred and mixed until uniformity, 0.82 g of sodium hydroxide (NaOH mass fraction 97%), 0.64 g of template R (N-methylpyrrolidine (NMP) mass fraction 99%), 0.85 g of template R (1, 5-Dibromopentane (DBP) mass fraction 97%), 0.13 g of seed crystal and 2.53 g of active silicon dioxide (SiO 2 mass fraction 95%) are added in sequence under stirring, and are stirred thoroughly and uniformly.
Covering a polytetrafluoroethylene lining filled with the reaction mixture, putting the polytetrafluoroethylene lining into a stainless steel autoclave for sealing, putting the autoclave into a rotary convection oven, setting the rotating speed to be 20r/min, and carrying out first-stage crystallization under autogenous pressure: crystallizing for 3d at 135 ℃, then heating to 175 ℃ and carrying out second-stage crystallization: crystallizing at 175 deg.c for 4d, filtering or centrifuging to obtain solid phase, washing the solid phase with deionized water to neutrality, and drying at 110 deg.c for 12 hr to obtain molecular sieve powder.
Example 5
A synthesis method of an IM-5 molecular sieve comprises the following steps:
0.13 g of aluminum isopropoxide (Al 2O3 mass fraction 24.46%) and 17.89 g of deionized water are stirred and mixed until uniform, and 0.66 g of sodium hydroxide (NaOH mass fraction 97%), 10.48 g of template agent R (N-methylpyrrolidine (NMP) mass fraction 99%), 20.47 g of template agent R (1, 5-Dibromopentane (DBP) mass fraction 97%), 0.18 g of seed crystal and 2.53 g of active silicon dioxide (SiO 2 mass fraction 95%) are added in sequence under stirring and fully stirred until uniform.
Covering a polytetrafluoroethylene lining filled with the reaction mixture, putting the polytetrafluoroethylene lining into a stainless steel autoclave for sealing, putting the autoclave into a rotary convection oven, setting the rotating speed to be 20r/min, and carrying out single-stage crystallization under autogenous pressure: crystallizing at 170deg.C for 5d, taking out crystallized product when the temperature of autoclave is reduced to room temperature, filtering or centrifuging, washing the obtained solid phase with deionized water to neutrality, and drying at 110deg.C for 12 hr to obtain molecular sieve raw powder.
Example 6
A synthesis method of an IM-5 molecular sieve comprises the following steps:
1.21 g of aluminum nitrate nonahydrate (Al 2O3 mass fraction 13.45%) and 21.31 g of deionized water are stirred and mixed until uniform, and 0.99 g of sodium hydroxide (NaOH mass fraction 97%), 10.32 g of template agent R (N-methylpyrrolidine (NMP) mass fraction 99%), 20.38 g of template agent R (1, 5-Dibromopentane (DBP) mass fraction 97%), 0.20 g of seed crystal and 2.45 g of white carbon black (SiO 2 mass fraction 98%) are sequentially added under stirring and fully stirred until uniform.
Covering a polytetrafluoroethylene lining filled with the reaction mixture, putting the polytetrafluoroethylene lining into a stainless steel autoclave for sealing, putting the autoclave into a rotary convection oven, setting the rotating speed to be 20r/min, and carrying out single-stage crystallization under autogenous pressure: crystallizing at 180 deg.c for 5d, filtering or centrifuging to obtain solid phase, washing the solid phase with deionized water to neutrality, and drying at 110 deg.c for 12 hr to obtain molecular sieve powder.
Example 7
A synthesis method of an IM-5 molecular sieve comprises the following steps:
0.61 g of aluminum nitrate nonahydrate (Al 2O3 mass fraction 13.45%) and 28.51 g of deionized water are stirred and mixed until uniform, and 1.15 g of sodium hydroxide (NaOH mass fraction 97%), 11.10 g of template agent R (N-methylpyrrolidine (NMP) mass fraction 99%), 21.42 g of template agent R (1, 5-Dibromopentane (DBP) mass fraction 97%), 0.08 g of seed crystal and 2.58 g of solid silica gel (SiO 2 mass fraction 93%) are added in sequence under stirring and stirred uniformly.
Covering a polytetrafluoroethylene lining filled with the reaction mixture, putting the polytetrafluoroethylene lining into a stainless steel autoclave for sealing, putting the autoclave into a rotary convection oven, setting the rotating speed to be 20r/min, and carrying out first-stage crystallization under autogenous pressure: crystallizing for 2d at 145 ℃, then heating to 185 ℃ and carrying out second-stage crystallization: crystallizing at 185 deg.c for 5d, filtering or centrifuging to obtain solid phase, washing the solid phase with deionized water to neutrality, and drying at 90 deg.c for 12 hr to obtain molecular sieve powder.
Example 8
A modification method of an IM-5 molecular sieve comprises
Step a: 100g (dry basis) of the raw powder of the IM-5 molecular sieve synthesized in the example 1 is added with 800g of water for pulping, 40g of NH 4 Cl is added, the temperature is raised to 80 ℃, after 1h of exchange treatment, the content of Na 2 O (calculated on the dry basis) is lower than 0.2wt%, and the molecular sieve filter cake is obtained after filtering and washing;
Step b: drying the obtained filter cake, and roasting at 550 ℃ in air atmosphere for 4 hours;
Step c: weighing 10.0g of roasted product, adding 200mL of HNO 3 solution with the concentration of acid solution of 6mol/L, heating to 100 ℃ and continuously stirring for 8 hours, cooling the liquid to room temperature, filtering, washing with deionized water to be neutral, and drying a filter cake;
Step d: weighing 20.0g of the dried product obtained in the step c after the acid treatment, and mixing and pulping with a template agent R1, a template agent R2 and water according to the molar ratio of 1:0.05:0.02:10, wherein the template agent R1 is N-methylpyrrolidine; template R2 is 1, 5-Dibromopentane (DBP); adding 3.84g of magnesium nitrate hexahydrate, reacting for 2d at 140 ℃ and reacting for 2d at 180 ℃, filtering, washing and drying the slurry after the reaction is finished, then carrying out ammonium exchange again according to the method of the ammonium exchange step a, and then carrying out roasting again according to the method of the roasting step b to obtain the metal-loaded molecular sieve.
Example 9
A method for modifying an IM-5 molecular sieve comprising:
step a: 100g (dry basis) of raw powder of the IM-5 molecular sieve synthesized in the example 2 is added with 800g of water for pulping, 40g of NH 4 C1 is added, the temperature is raised to 80 ℃, after 2 hours of exchange treatment, the content of Na 2 O (calculated on the dry basis) is lower than 0.2wt%, and the molecular sieve filter cake is obtained after filtration and washing;
step b: drying the obtained filter cake, and roasting at 550 ℃ in air atmosphere for 4 hours;
Step c: weighing 10.0g of the obtained roasted product, adding 200mL of HNO 3 solution with the concentration of acid solution of 10mol/L, heating to 100 ℃ and continuously stirring for 8 hours, cooling the liquid to room temperature, filtering, washing with deionized water to be neutral, and drying a filter cake;
Step d: weighing 20.0g of the dried product obtained in the step c after the acid treatment, and mixing and pulping with a template agent R1, a template agent R2 and water according to the molar ratio of 1:0.06:0.03:15, wherein the template agent R1 is N-methylpyrrolidine; template R2 is 1, 5-Dibromopentane (DBP); adding 1.28g of magnesium nitrate hexahydrate, reacting for 5d at 170 ℃, filtering, washing and drying the slurry after the reaction is finished, then carrying out ammonium exchange again according to the method of the ammonium exchange step a, and then carrying out roasting again according to the method of the roasting step b to obtain the metal-loaded molecular sieve. The catalyst has catalytic action in the processes of n-butene, pentene isomerization, toluene methanol alkylation reaction and the like.
Comparative example 1
This comparative example is intended to illustrate a process for synthesizing a molecular sieve according to example 6 of patent CN 103466652B, and comprises the following steps:
4.5g of silica gel, 0.5g of sodium aluminate, 2.5g of sodium hydroxide, 3g of sodium bromide, 8.7g of dibromopentane, 6.2g N-methylpyrrole and 65g of deionized water are stirred uniformly at room temperature to obtain a synthetic liquid. And (3) transferring the prepared synthetic solution into a crystallization kettle, sealing, and crystallizing at 200 ℃ for 6 days. Washing to neutrality, drying at 110 deg.c for 12 hr, and roasting at 550 deg.c for 6 hr to obtain IM-5 molecular sieve product.
The application adopts 4.5 g of silica gel as a silicon source, the maximum usage amount of dibromopentane is 2.59g, the maximum usage amount of N-methylpyrrole is 2.04g, and crystal seeds are added into a synthesis system, so that more crystal fragments and secondary structural units can be provided, the rapid nucleation of a crystallization system is promoted, more crystal nuclei are formed in the system, the usage amount of a template agent is reduced, and the environmental pollution is reduced.
Comparative example 2
This comparative example is intended to illustrate a process for synthesizing a molecular sieve according to example 2 of patent CN 110407228B, and comprises the following steps:
33.22g of 1-methylpyrrolidine and 48mL of diethyl ether were mixed under stirring, and 43.97g of 1, 5-dibromopentane was added dropwise to the above mixture at a rate of 10 drops/sec, followed by a pre-reaction at 35℃for 16 hours to give a pre-reaction product A. The molar ratio of the 1, 5-dibromopentane, the 1-methylpyrrolidine and the solvent diethyl ether is 1:2.04:2.47.
Dissolving the pre-reaction product A, 43.78gNaAlO 2 solution and 53.46ml30 wt% NaOH solution in a proper amount of deionized water, uniformly mixing, slowly adding 150g of solid silica gel under the condition of stirring to prepare a milky colloidal mixture to be crystallized, continuously stirring for 1h, transferring into a 1L high-pressure reaction kettle with mechanical stirring, carrying out first-stage hydrothermal crystallization at 140 ℃ for 2 days, heating to 172 ℃ for second-stage hydrothermal crystallization for 4 days, stopping crystallization reaction, washing and filtering the product, and drying at 80 ℃ for 12h to obtain the molecular sieve raw powder.
According to examples 1-7, compared with comparative example 1, the example of the application omits the pre-reaction process of two raw materials 1, 5-dibromopentane and N-methylpyrrolidine in a solvent, reduces the use of solvents such as water, alcohol, ketone, ether, ester and the like, and is more environment-friendly in production process.
The conversion and yield of the modified molecular sieves obtained in examples 1 and 2 in catalyzing the isomerization reaction of n-pentene were used.
Samples S1 (IM-5 molecular sieve prepared in example 1), S2 (IM-5 molecular sieve prepared in example 2), S8 (modified IM-5 molecular sieve prepared in example 8), and S9 (modified IM-5 molecular sieve prepared in example 9) obtained in the above examples were respectively subjected to tabletting and grinding to obtain particles of 20-40 meshes, the catalyst loading volume was 10mL, the reactant was n-pentene, the liquid volume space velocity was 2h -1, the reaction was carried out under normal pressure, and the reaction temperature was 310 ℃. The reaction was carried out for 24 hours under the above reaction conditions, and the conversion and yield of the product were calculated. The micro-inverse evaluation data are shown in Table 1, such as: conversion and yield.
Conversion = (mass of n-pentene in feed-mass of n-pentene in product)/(mass of n-pentene in feed) ×100%
Yield = (mass of isoamylene in product)/(mass of n-pentene in raw material) ×100%
The selectivity can also be calculated accordingly as yield/conversion 100%.
Table 1 summary of experimental data
It can be seen from Table 1 that the IM-5 sieves and modified sieves prepared in examples 1,2, 8 and 9 are capable of catalyzing the isomerization of n-butenes and pentenes during the alkylation of toluene and methanol.
The above embodiments are merely illustrative of the present invention and are not to be construed as limiting the scope of the present invention, and all designs which are the same or similar to the present invention are within the scope of the present invention.

Claims (10)

1. A modification method of an IM-5 molecular sieve prepared by a synthesis method of the IM-5 molecular sieve is characterized by comprising the following steps of:
Fully stirring and mixing 1, 5-Dibromopentane (DBP), N-methylpyrrolidine, an aluminum source, inorganic base, seed crystals, a silicon source and water to obtain an initial gel mixture; the seed crystal is Na-type IM-5 molecular sieve for removing the template agent;
adding the initial gel mixture into a crystallization kettle for further crystallization to obtain a crystallization product;
Carrying out solid-liquid separation on the obtained crystallized product, and washing a solid-phase product obtained by the solid-liquid separation with deionized water to be neutral to obtain a neutral solid-phase product;
drying the neutral solid phase product at 90-120 ℃, and then roasting at 400-700 ℃ to obtain an IM-5 molecular sieve;
The modification method of the IM-5 molecular sieve comprises the following steps:
Step a, carrying out ammonium exchange treatment on the obtained IM-5 molecular sieve and ammonium salt to obtain an ammonium exchange molecular sieve;
Step b, performing high-temperature roasting treatment on the ammonium exchange molecular sieve to remove the organic amine template agent, thereby obtaining an H-type molecular sieve;
Step c, dealuminating the H-type molecular sieve to obtain a dealuminated molecular sieve; the silicon-aluminum ratio of the dealuminated molecular sieve is 220-500:1;
Step d, washing and drying the obtained dealuminated molecular sieve, mixing the dealuminated molecular sieve with 1, 5-Dibromopentane (DBP), N-methylpyrrolidine, water and load metal, crystallizing the mixture, and obtaining slurry for secondary cleaning;
And e, repeating the step a and the step b on the molecular sieve after the secondary cleaning and drying to obtain the modified IM-5 molecular sieve.
2. The method for modifying an IM-5 molecular sieve produced by the synthesis method of an IM-5 molecular sieve according to claim 1, wherein the molar ratio of the aluminum source, the silicon source, the 1, 5-Dibromopentane (DBP), the N-methylpyrrolidine, the inorganic base, and the water is: 0.008-0.05:1:0.03-0.15:0.05-0.32:0.3-0.8:20-50; the seed crystal is 3% -8% of the silicon source addition.
3. The method for modifying an IM-5 molecular sieve produced by the synthesis method according to claim 1, wherein when the initial gel mixture is added into the crystallization kettle for crystallization, a single-stage temperature crystallization is adopted, and the conditions of the single-stage temperature crystallization are as follows: crystallizing at 140-210 deg.c for 4-12d.
4. The method for modifying an IM-5 molecular sieve produced by the synthesis method according to claim 1, wherein when the initial gel mixture is added into the crystallization kettle for crystallization, a two-stage temperature crystallization is adopted, the two-stage temperature crystallization comprises a first-stage temperature crystallization and a second-stage temperature crystallization, and the conditions of the first-stage temperature crystallization are as follows: crystallizing at 130-170 deg.c for 1-5d; the crystallization conditions at the second stage temperature are as follows: crystallizing at 170-200deg.C for 1-7d.
5. The method for modifying an IM-5 molecular sieve produced by the synthesis method according to claim 1, wherein the silicon source is at least one selected from the group consisting of silica sol, activated silica and solid silica gel.
6. The method for modifying an IM-5 molecular sieve produced by the synthesis method according to claim 1, wherein the aluminum source comprises at least one of aluminum salt, pseudo-boehmite, aluminum isopropoxide, aluminum hydroxide gel and activated alumina.
7. The method for modifying an IM-5 molecular sieve produced by the synthesis method according to claim 1, wherein the inorganic base is at least one selected from the group consisting of sodium hydroxide and potassium hydroxide.
8. The method for modifying an IM-5 molecular sieve produced by the synthesis method of an IM-5 molecular sieve according to claim 1, wherein in step c, the H-type molecular sieve is dealuminized by acid treatment, and the acid is one or more of hydrochloric acid, nitric acid, sulfuric acid, citric acid and hydrofluoric acid, and the concentration range of the acid is: 4-12 mol/L, wherein the treatment temperature is 50-100 ℃ and the treatment time is 2-24 h when the acid treatment is carried out.
9. The method for modifying an IM-5 molecular sieve produced by the synthesis method of an IM-5 molecular sieve according to claim 1, wherein in step d, the molar ratio of dealuminated molecular sieve, 1, 5-Dibromopentane (DBP), N-methylpyrrolidine, water is 1:0.015-0.05:0.04-0.12:5-30; the content of the load metal is 0.1-5wt%.
10. The method for modifying an IM-5 molecular sieve produced by a synthesis method according to claim 1 or 9, wherein the supported metal is one or more selected from the group consisting of magnesium, calcium, barium, scandium, titanium, vanadium, chromium, nickel, copper, zinc, and tungsten.
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