阅读说明：本技术 Scm-28分子筛及其制备方法和应用 (SCM-28 molecular sieve, and preparation method and application thereof ) 是由 陶伟川 袁志庆 王振东 于 2019-09-19 设计创作，主要内容包括：本发明公开了一种新型结构的SCM-28分子筛及其制备方法和应用。该SCM-28分子筛具有如下的摩尔比的化学组成：SiO-2：nAl-2O-3,0.005≤n≤0.4,所述的SCM-28分子筛其XRD衍射图谱中晶面间距包括以及对应的相对强度为10-60、10-40、10-40、10-40、30-80、10-60、30-100、10-60、20-70、10-80、10-70。本发明提供的SCM-28分子筛可以用于催化、吸附等领域。(The invention discloses an SCM-28 molecular sieve with a novel structure and a preparation method and application thereof. The SCM-28 molecular sieve has the following chemical composition in molar ratio: SiO 2 2 ：nAl 2 O 3 N is more than or equal to 0.005 and less than or equal to 0.4, and the SCM-28 molecular sieve has an XRD diffraction pattern with interplanar spacing And the corresponding relative intensity is 10-60, 10-40, 30-80, 10-60, 30-100, 10-60, 20-70, 10-80, 10-70. The SCM-28 molecular sieve provided by the invention can be used in the fields of catalysis, adsorption and the like.)

1. An SCM-28 molecular sieve comprising the chemical composition in the following molar ratios: SiO 2₂：nAl₂O₃0.005 is less than or equal to n is less than or equal to 0.4, and the SCM-28 molecular sieve comprises an XRD diffraction pattern shown as the following table:

。

2. the SCM-28 molecular sieve of claim 1, further comprising an XRD diffraction pattern as shown in the following table:

。

3. the SCM-28 molecular sieve of claim 1, wherein the SCM-28 molecular sieve comprises a molar ratio of SiO₂：nAl₂O₃Wherein n is more than or equal to 0.01 and less than or equal to 0.2.

4. A method of making the SCM-28 molecular sieve of any of claims 1 to 3, comprising the steps of:

crystallizing a mixture formed by a silicon source, an aluminum source, a template agent T, an additive L and water to obtain the molecular sieve;

wherein the template T is an organic template T selected from the compounds of the following structural formula (A):

5. the method of claim 4, wherein the compound of formula (a) in the template T is in the form of a quaternary ammonium salt or a quaternary ammonium base.

6. The method of claim 4, wherein the aluminum source, the silicon source, the templating agent T, the additive L, and the water are present in the form of Al in a molar ratio, based on the weight of the aluminum source, the silicon source, the templating agent T, and the water₂O₃:SiO₂:T:L:H₂O is 1: (10-150): (1-50): (0.2-40): (500-5000).

7. The method of claim 6, wherein the step of preparing the SCM-28 molecular sieve comprises using aluminum source, silicon source, and templateAgent T, additive L and water, calculated according to molar ratio, Al₂O₃:SiO₂:T:L:H₂O is 1 (10 to 100), (2 to 16), (2 to 20) or (500 to 2000).

8. The method for preparing the SCM-28 molecular sieve of claim 4, wherein the crystallization conditions in the step are as follows: the crystallization temperature is 160-240 ℃, and the crystallization time is 80-300 hours.

9. The method of preparing the SCM-28 molecular sieve of claim 4 wherein the aluminum source is selected from at least one of aluminates, meta-aluminates, aluminum salts, aluminum hydroxides, aluminum isopropoxide; the silicon source is at least one of organic silicon, silica sol, diatomite or water glass.

10. The method of making the SCM-28 molecular sieve of claim 4, wherein the additive L is a basic material or an alkali metal salt; the alkaline substance is selected from at least one of lithium oxide, sodium oxide, potassium oxide, cesium oxide, lithium hydroxide, sodium hydroxide, potassium hydroxide and cesium hydroxide; the alkali metal salt is at least one selected from an oxalate, a sulfate, an acetate, a nitrate, a carbonate, a phosphate and a halide of an alkali metal element.

11. A molecular sieve composition comprising the SCM-28 molecular sieve of any of claims 1-3 or the SCM-28 molecular sieve prepared according to the method of any of claims 4-10, and a binder.

12. Use of the SCM-28 molecular sieve of any of claims 1 to 3, the SCM-28 molecular sieve prepared according to the SCM-28 molecular sieve preparation method of any of claims 4 to 10, or the molecular sieve composition of claim 11 as an adsorbent or catalyst.

Technical Field

The invention relates to an SCM-28 molecular sieve and a preparation method thereof, and the SCM-28 molecular sieve is used as an adsorbent or a catalyst.

Background

Porous materials are a class of solid compounds with regular pore structure, which can be classified into the following three classes according to their pore diameters, as defined by the International Union of Pure and Applied Chemistry (IUPAC): the material with the pore diameter less than 2nm is microporous material; the material with the pore diameter between 2 and 50nm is mesoporous material (mesoporous materials); materials with pore sizes greater than 50nm are macroporous materials (macroporous materials) and zeolite molecular sieve channels are typically below 2nm in diameter and are therefore classified as microporous materials.

Zeolite molecular sieve is a crystalline silicate material composed of silicon-oxygen tetrahedron [ SiO ]₄]^4-And alundum tetrahedron [ AlO₄]^5-Linked by a common oxygen atom, collectively known as TO₄The tetrahedral (primary structure unit), in which the silicon element can also be isomorphously substituted by other elements, especially some trivalent or tetravalent elements such as Al, B, Ga, Ge, Ti, etc., has wide application in the fields of catalysis, adsorption and ion exchange, etc. due to some specificities in their structure and chemical properties. One key factor determining the application performance of molecular sieves is the characteristics of the pore channels or cage cavities of the molecular sieves, which are determined by the intrinsic crystal structures of the molecular sieves, so that the molecular sieves with new crystal structures are obtained, which is of great significance for developing the application of the molecular sieves.

Some molecular sieves are available in nature, however, most of the molecular sieves that find practical application in the catalytic field are obtained by artificial synthesis. In the last 40 th century, Barrer and the like synthesized artificial zeolite which does not exist in nature for the first time in a laboratory, and in nearly more than ten years thereafter, Milton, Breck, Sand and the like added alkali metal or alkaline earth metal hydroxide into aluminosilicate gel by adopting a hydrothermal technology to prepare A-type, X-type, L-type and Y-type zeolites, mordenite and the like; in the early sixties of the last century, with the introduction of organic base cations, a series of zeolite molecular sieves with completely new structures, such as ZSM-n series (ZSM-5(US 3702886), ZSM-11(US 3709979), ZSM-23(US 4076842), ZSM-35(US 4016245) and the like) zeolite molecular sieves, were prepared.

In 1982, Wilson S.T. and Flarigen E.M. of scientists of United states of America Union carbide (UCC) and others successfully synthesized and developed a brand-new molecular sieve family, aluminum phosphate molecular sieve AlPO, using aluminum source, phosphorus source and organic template₄N, n represents the model number (US 4310440). Two years later, UCC in AlPO₄Based on-n, Si atoms are used for partially replacing Al atoms and P atoms in an AlPO framework, and another series of silicoaluminophosphate molecular sieves SAPO-n are successfully prepared, wherein n represents the type (US4440871, US 4499327).

The molecular sieve is prepared by a hydrothermal synthesis method. Therefore, the hydrothermal synthesis method is the most commonly used method for synthesizing molecular sieves, and a typical hydrothermal synthesis method mainly comprises the steps of firstly, uniformly mixing a silicon source, an aluminum source, a structure directing agent, alkali, water and the like to react to obtain initial sol, namely a crystallization mixture, then placing the crystallization mixture in a reaction kettle with a polytetrafluoroethylene lining and a stainless steel outer wall, sealing, and then carrying out crystallization reaction at a certain temperature and a certain autogenous pressure, like the process of earth rock making.

In the current state of the art, however, no new SCM-28 molecular sieve has been obtained.

Disclosure of Invention

The invention aims to provide an SCM-28 molecular sieve with a novel structure and a preparation method and application thereof.

In order to solve the technical problems, the invention provides an SCM-28 molecular sieve which has the following chemical composition in molar ratio:SiO₂：nAl₂O₃0.005 ≦ n ≦ 0.4, and the SCM-28 molecular sieve comprises the XRD diffraction pattern as follows:

further, the SCM-28 molecular sieve also includes an XRD diffraction pattern as shown in the following table:

。

further, the SCM-28 molecular sieve contains SiO in a molar ratio₂：nAl₂O₃Wherein n is preferably 0.01. ltoreq. n.ltoreq.0.2.

In order to solve the technical problems, the invention also provides a preparation method of the SCM-28 molecular sieve, which comprises the following steps:

crystallizing a mixture formed by a silicon source, an aluminum source, a template agent T, an additive L and water to obtain the molecular sieve;

wherein the templating agent T is an organic templating agent T selected from the group consisting of compounds of the following structural formula (A), preferably a quaternary ammonium salt thereof or a quaternary ammonium base form thereof:

further, the aluminum source in the step is Al₂O₃The silicon source is calculated by SiO₂The template agent T, the additive L and water are calculated according to the molar ratio, and Al is calculated₂O₃:SiO₂:T:L:H₂O is 1: (10-150): (1-50): (0.2-40): (500 to 5000), preferably 1 (10 to 100): (2 to 16): 2 to 20): 500 to 2000.

Further, the crystallization conditions in the step are as follows: the crystallization temperature is 160-240 ℃, and the crystallization time is 80-300 hours.

Further, the aluminum source is selected from at least one of aluminate, meta-aluminate, aluminum salt, aluminum hydroxide and aluminum isopropoxide; the silicon source is at least one of organic silicon, silica sol, diatomite or water glass.

Further, the additive L is an alkaline substance or an alkali metal salt; the alkaline substance is selected from at least one of lithium oxide, sodium oxide, potassium oxide, cesium oxide, lithium hydroxide, sodium hydroxide, potassium hydroxide and cesium hydroxide; the alkali metal salt is at least one selected from an oxalate, a sulfate, an acetate, a nitrate, a carbonate, a phosphate and a halide of an alkali metal element.

Further, the organic template T is prepared by adopting a conventional method in the field.

Furthermore, the product obtained after the mixture is crystallized in the step can be filtered, washed and dried, and then the product is roasted according to the conventional roasting condition. In the invention, the drying temperature is 20-120 ℃, the drying time is 1-36 h, the roasting temperature is 500-750 ℃, the roasting atmosphere is air, and the roasting time is 4-10 h. Other conventional chemical methods for drying and removing the template agent may also be used.

The SCM-28 molecular sieve has a stable crystal structure, and can be treated according to a conventional roasting method, for example, roasting treatment is carried out at 500-750 ℃ in an air atmosphere, and a certain amount of carbon-containing substances may be left in the molecular sieve according to different roasting conditions.

The SCM-28 molecular sieves provided by the present invention may be used in any physical form, such as a powder, a pellet, or a molded article (e.g., a bar, a clover, etc.). These physical forms can be obtained in any manner conventionally known in the art and are not particularly limited.

The invention also provides a molecular sieve composition, which comprises the SCM-28 molecular sieve or the SCM-28 molecular sieve prepared according to the preparation method of the SCM-28 molecular sieve. Other materials contained in the molecular sieve composition may be active and inactive materials. Other molecular sieves may be used as the active material, and clays, alumina, silica gel, etc., may be used as the inactive material (generally referred to as a binder). These other materials may be used singly or in combination of plural kinds in any ratio. As the amount of the other materials, those conventionally used in the art can be referred to, and there is no particular limitation.

The SCM-28 molecular sieve, the SCM-28 molecular sieve prepared by the preparation method of the SCM-28 molecular sieve or the molecular sieve composition can be used as an adsorbent or a catalyst. For example, to separate at least one component from a mixture of components in the gas or liquid phase. The SCM-28 molecular sieve may then be used, for example, as a catalyst (or as a catalytically active component thereof), either directly or after conventional treatment in the art (e.g., ion exchange, etc.), as an organic conversion catalyst.

Compared with the prior art, the invention has the following advantages:

the SCM-28 molecular sieve provided by the invention has a unique XRD diffraction pattern. Compared with the molecular sieve in the prior art, the preparation method of the molecular sieve is simple and easy to implement, mild in operation condition and easy to obtain high-purity products with low cost and high yield. The molecular sieve can be applied to the fields of adsorption, catalysis and the like.

Drawings

FIG. 1 is an XRD spectrum of SCM-28 obtained in example 1;

FIG. 2 is a scanning electron micrograph of SCM-28 obtained in example 1;

FIG. 3 is an XRD spectrum of SCM-28 obtained in example 2.

Detailed Description

The following examples are provided to further illustrate the technical solutions of the present invention, but the present invention is not limited to the following examples.

In the present invention, percentages and percentages are by mass unless otherwise specifically indicated.

Throughout the specification and claims, unless explicitly described otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated step or element but not the exclusion of any other step or element.

In the present invention, including the examples below, the structure and morphology of the SCM-28 molecular sieve was determined by X-ray diffraction, scanning electron microscopy characterization, respectively.

The XRD measurement method of the molecular sieve product comprises the following steps: analyzing the phase of the sample by X' Pert X-ray powder diffractometer of Pasnaceae, CuK alpha ray sourceThe scanning range of 2 theta of the nickel filter is 3-50 degrees, the operating voltage is 40KV, the current is 40mA, the scanning speed is 0.11 degrees/s, and the scanning step length is 0.033 degrees.

The silicon-aluminum ratio measuring method comprises the following steps: the samples were weighed, dissolved in a mixed solution of hydrofluoric acid and perchloric acid, and then subjected to ICP testing using a Varian 725-ES ICP optical Emission Spectrometer.

[ example 1 ]

Weighing 0.64 g of aluminum isopropoxide, adding 3.99 g of deionized water, adding 3.34 g of 30 wt% sodium hydroxide solution, stirring for 10 minutes, adding 19.3 g of 16 wt% N, N' - (1, 4-phenylenebis (methylene)) bis (N-methylpyrrolidine) ammonium hydroxide (hereinafter abbreviated as T) solution, stirring for 15 minutes, adding 7.5g of 40% silica sol, and stirring for 4 hours to obtain a synthetic mother liquor with the following molar ratio composition:

0.5Al₂O₃:16SiO₂:3.2T:8Na:480H₂O

crystallizing the above synthetic mother liquor in a sealed reaction container at crystallization temperature of 175 deg.C for 110 hr, washing and drying the crystallized product at 90 deg.C for 12 hr, and calcining at 550 deg.C in air atmosphere for 6 hr to obtain SCM-28 molecular sieve with XRD pattern shown in figure 1 and SiO₂：0.094Al₂O₃The chemical composition of (a). The obtained SCM-28 molecular sieve is characterized by having polyhedral morphology as shown in figure 2 through a scanning electron microscope. The XRD diffraction interplanar spacing data are as follows:

[ example 2 ]

Weighing 0.52 g of aluminum sulfate octadecahydrate, adding 3.93 g of deionized water, adding 2g of 30 wt% sodium hydroxide solution, stirring for 10 minutes, adding 15 g of T solution with the weight concentration of 16 wt%, stirring for 15 minutes, adding 11.72 g of 40% silica sol, and stirring for 1 hour to obtain a synthetic mother liquor with the following molar ratio:

0.5Al₂O₃:50SiO₂:5T:10Na:900H₂O

crystallizing the synthetic mother liquor in a closed reaction container at 205 deg.C for 196 hr, washing and drying at 90 deg.C for 12 hr, and calcining at 550 deg.C in air atmosphere for 6 hr to obtain SCM-28 molecular sieve containing SiO₂：0.031Al₂O₃Has an XRD pattern as shown in fig. 3. The XRD diffraction interplanar spacing data are as follows:

[ example 3 ]

Weighing 0.256 g of sodium aluminate, adding 0.7 g of potassium hydroxide, adding 7.46 g of deionized water, stirring for 10 minutes, adding 7.52 g of T solution with the weight concentration of 16 wt%, stirring for 25 minutes, adding 2.34 g of 40% silica sol, and stirring for 1 hour to obtain a synthetic mother liquor with the following molar ratio:

0.5Al₂O₃:5SiO₂:1.25T:1Na:4K:270H₂O

crystallizing the above synthetic mother liquor in a sealed reaction container at 240 deg.C for 144 hr, washing the crystallized product, and drying at 90 deg.CAnd drying for 12h, and roasting at 550 ℃ for 6h under an air atmosphere to obtain the SCM-28 molecular sieve. It has SiO₂：0.37Al₂O₃The XRD diffraction interplanar spacing data are as follows:

[ example 4 ]

Weighing 0.32 g of aluminum isopropoxide, adding 3.63 g of deionized water, adding 2.08 g of 30 wt% sodium hydroxide solution, stirring for 20 minutes, adding 23.44 g of ethyl orthosilicate, stirring for 30 minutes, adding 24.1 g of T solution with the weight concentration of 16 wt%, and stirring for 4 hours to obtain a synthetic mother liquor with the following molar ratio:

0.5Al₂O₃:70SiO₂:8T:10Na:900H₂O

stirring the synthetic mother liquor at 80 ℃ for 30 minutes, then transferring the synthetic mother liquor into a closed reaction container for crystallization, wherein the crystallization temperature is 240 ℃, the crystallization time is 144 hours, washing and drying the crystallized product at 90 ℃ for 12 hours, and roasting at 550 ℃ for 6 hours under an air atmosphere to obtain the SCM-28 molecular sieve. It has SiO₂：0.024Al₂O₃The XRD diffraction interplanar spacing data are as follows:

[ example 5 ]

Weighing 0.32 g of aluminum isopropoxide, adding 2.79 g of deionized water, stirring for 10 minutes, adding 69.24 g of a T solution with the weight concentration of 16 wt%, stirring for 15 minutes, adding 1.875g of 40% silica sol, stirring for 4 hours, adding 3.75 g of a 30 wt% sodium hydroxide solution, and uniformly stirring to obtain a synthetic mother liquor with the following molar ratio:

0.5Al₂O₃:8SiO₂:23T:18Na:2300H₂O

putting the synthetic mother liquor into a closed reaction containerCrystallizing at 240 deg.c for 288 hr, washing and drying at 90 deg.c for 12 hr, and roasting at 550 deg.c in air atmosphere for 6 hr to obtain SCM-28 molecular sieve. It has SiO₂：0.19Al₂O₃The XRD diffraction interplanar spacing data are as follows:

[ example 6 ]

Weighing 0.32 g of aluminum isopropoxide, adding 6.54 g of deionized water, adding 0.088 g of potassium hydroxide, stirring for 20 minutes, adding 1.67 g of ethyl orthosilicate, stirring for 30 minutes, adding 2.26 g of a T solution with the weight concentration of 16 wt%, and stirring for 4 hours to obtain a synthetic mother liquor with the following molar ratio:

0.5Al₂O₃:5SiO₂:0.75T:1K:300H₂O

stirring the synthetic mother liquor at 80 ℃ for 30 minutes, then transferring the synthetic mother liquor into a closed reaction container for crystallization, wherein the crystallization temperature is 168 ℃, the crystallization time is 96 hours, washing and drying the crystallized product at 90 ℃ for 12 hours, and roasting at 550 ℃ for 6 hours under an air atmosphere to obtain the SCM-28 molecular sieve. It has SiO₂：0.17Al₂O₃The XRD diffraction interplanar spacing data are as follows:

[ example 7 ]

0.52 g of aluminum sulfate octadecahydrate is weighed, 0.73 g of sodium chloride is added, 18.1 g of T solution with the weight concentration of 16 wt% is added, 4.69 g of 40% silica sol is added after stirring for 1 hour, and a synthetic mother liquor with the following molar ratio composition is obtained after stirring for 1 hour:

0.5Al₂O₃:20SiO₂:6T:8Na:650H₂O

and (2) placing the synthetic mother liquor in a closed reaction container for crystallization, wherein the crystallization temperature is 190 ℃, the crystallization time is 168 hours, washing and drying the crystallized product at 90 ℃ for 12 hours, and roasting at 550 ℃ for 6 hours in an air atmosphere to obtain the SCM-28 molecular sieve. It has SiO₂：0.13Al₂O₃The XRD diffraction interplanar spacing data are as follows:

[ example 8 ]

Weighing 0.32 g of aluminum isopropoxide, adding 0.3 g of lithium hydroxide, adding 3.38 g of deionized water, stirring for 20 minutes, adding 6.09 g of 40% silica sol, stirring for 30 minutes, adding 9.03 g of T solution with the weight concentration of 16 wt%, and stirring for 4 hours to obtain a synthetic mother liquor with the following molar ratio:

0.5Al₂O₃:26SiO₂:3T:8Li:520H₂O

stirring the synthetic mother liquor at 80 ℃ for 30 minutes, then transferring the synthetic mother liquor into a closed reaction container for crystallization, wherein the crystallization temperature is 240 ℃, the crystallization time is 144 hours, washing and drying the crystallized product at 90 ℃ for 12 hours, and roasting at 550 ℃ for 6 hours under an air atmosphere to obtain the SCM-28 molecular sieve. It has SiO₂：0.058Al₂O₃The XRD diffraction interplanar spacing data are as follows:

[ example 9 ]

The product molecular sieve obtained in example 1 was mixed with 10 mass% magnesium acetate solution as molecular sieve-magnesium acetate solution

Putting the mixture into a three-neck flask according to the mass ratio of 1:10, stirring the mixture for 100 minutes in a water bath at 65 ℃, filtering and washing the mixture, repeating the operation for 3 times, putting the product into an oven at 100 ℃ for drying overnight to obtain powder, and characterizing the powder by an X-ray diffractometer to still keep the structure of SCM-28.

[ example 10 ]

A sample of 4.2g of the powder prepared in example 9 was mixed thoroughly with 15.8g of alumina and 0.54g of sesbania powder, and then kneaded with a 12% by mass aluminum nitrate solution, extruded into a rod of 1.6X 2 mm in diameter, dried at 100 ℃ and calcined at 550 ℃ for 4 hours in an air atmosphere to prepare the desired molecular sieve composition which can be used as an adsorbent or a catalyst.

[ example 11 ]

Crushing and sieving the molecular sieve composition prepared in the example 10, taking 1g of particles with the particle size of 20-40 meshes, putting the particles into a fixed bed reactor, activating the particles for 8 hours at 300 ℃ in a nitrogen atmosphere, continuously introducing nitrogen, cooling the temperature to room temperature, introducing a mixed gas of water and nitrogen, wherein the water content is 200ppmv, and the volume space velocity is 300h^-1The adsorption time was 10 minutes, and the water content of the adsorbed gas was less than 1ppmv as analyzed by a dew point meter.