CN1721325A

CN1721325A - Process for preparing fine grain zeolite

Info

Publication number: CN1721325A
Application number: CN 200410052721
Authority: CN
Inventors: 王德举; 唐颐; 刘仲能; 谢在库; 张惠宁
Original assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Current assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Priority date: 2004-07-12
Filing date: 2004-07-12
Publication date: 2006-01-18
Anticipated expiration: 2024-07-12
Also published as: CN1290767C

Abstract

The present invention relates to the small crystal grain NaA zeolite preparing process and aims at lowering the cost of synthesizing small crystal grain NaA zeolite. The technological scheme of the present invention is that NaA zeolite is prepared through hydrothermal crystallization with SiO2 precursor obtained through hydrolyzing silicon sol or tetraethyl metasilicate as silicon source, sodium metaaluminate as aluminum source and molar material composition of Na2O in 4-9, Al2O3 in 0.4-4, SiO2 in 1 and H2O in 50-500, and under the conditions of crystallization temperature 40-100 deg.c and crystallization time 2-72 hr. The technological scheme of the present invention may be used in industrial preparation of small crystal grain NaA zeolite.

Description

Little crystal grain prepare zeolite method

Technical field

The present invention relates to little crystal grain NaA prepare zeolite method, particularly about under the situation of no any organic additive, little crystal grain NaA prepare zeolite method.

Background technology

Zeolite is a kind of crystalline silico-aluminate, has that specific surface area is big, hydrothermal stability is high, micropore enriches equal first-class performance, is widely used as catalyzer, sorbent material, ion-exchanger and new function material.The zeolite molecular sieve of little crystal grain has bigger external surface area and short intracrystalline duct, therefore might have a lot of big incomparable performances of crystal grain zeolite: when using as catalyzer, reactant molecule is easy to arrive catalytic active site, and the product that generates can spread out from the duct soon, in the utilization ratio that improves catalyzer, strengthen macromolecular conversion capability, reduce the deep reaction of product, and reduce aspect such as catalyzer coking deactivation rate and all have more superior performance; As sorbent material and ion-exchanger, have ion-exchange speed and rate of adsorption faster; NaA zeolite ion-exchange speed and less size particle diameter faster makes it to be more suitable for to use as washing auxiliary detergent; In addition, short grained zeolite also is that the assembled material that is widely studied is in recent years constructed one of primitive.Therefore little crystal grain particularly has the zeolite synthesis of nano level (particle diameter is generally below 100 nanometers) size and property research thereof becomes one of focus of zeolite molecular sieve research field in recent years.

The NaA zeolite molecular sieve of industrial use mostly adopts the hydrothermal crystallizing method synthetic, and generally about 100 ℃, resulting product grains size is generally at one to several microns for its crystallization temperature.At present can be by adding directed agents (Wang Yangdong, Liu Yang, Dong Jialu, synthetic and brilliant looks [J] Deng small-grain A-type molecular sieve. the catalysis journal, 1998,19 (6): 610-612), microwave-assisted (Li Jinshu, Zhang Chun opens. synthetic 4A zeolite of microwave irradiation and sign [J]. and the spectrographic laboratory, 18 (3): 413-420) etc. method can obtain less NaA zeolite.The sieve and silica-sesquioxide that adopts the preparation of sol-gel supercritical drying is that reaction raw materials can obtain nano level NaA zeolite (Zhou Zhou at the organic complexing agent that adds aluminium by hydrothermal treatment consists, Guo Xikun, Pan Weixiong, Deng. the study on the synthesis [J] of nanometer 4A type molecular sieve. the gas chemical industry, 2001,26 (6): 4-7); Under optimal conditions comparatively hydro-thermal synthetic also can obtain less NaA zeolite and faujusite (Sun Jiayue Liu Chunsheng, storage just. Faujasite Using Hydrothermal-Static synthesize ultra micro NaA, faujasite molecular sieve [J]. institute of Fusun PetroleumCollege reports, 1997,17 (2): 1-4).Zhan etc. are then by synthetic coacervate (the Zhan B Z that has obtained nanometer NaX zeolite of low-temperature hydrothermal, White M A, Lumsden M, et al.Control of Particle Size and Surface Properties of Crystals of NaX Zeolite[J] .Chemistry ofMaterials, 2002,14 (9): 3636-3642).

Summary of the invention

Technical problem to be solved by this invention is to prepare in the A zeolite process all will use organic formwork agent in the past, makes the synthetic bigger problem of cost, and a kind of new little crystal grain NaA prepare zeolite method is provided.This method has and need not organic formwork agent in the preparation process, and synthetic cost is low, and can obtain the characteristics of little crystal grain NaA zeolite.

For solving the problems of the technologies described above, the technical solution used in the present invention is as follows: a kind of little crystal grain NaA prepare zeolite method, and with silicon sol or the SiO that obtains by positive tetraethyl orthosilicate hydrolysis ₂Precursor is the silicon source, is the aluminium source with the sodium metaaluminate, and material molar ratio consists of aNa ₂O: XAl ₂O ₃: SiO ₂: dH ₂O, a=4～9 wherein, X=0.4～4, d=50～500 are 40～100 ℃ at crystallization temperature, crystallization time is that hydrothermal crystallizing makes particle diameter less than 1 micron NaA zeolite under 2.0～72 hours conditions.

In the technique scheme, the crystallization temperature preferable range is 50～80 ℃, and the crystallization time preferable range is 2～20 hours, and more preferably scope is 5～14 hours.The value preferable range of a is 5～7; The value preferable range of X is 1.5～3.0, and value more preferably scope is 2.0～2.5; The value preferable range of d is 100～300.Preferred version was for adopting dynamic agitation when reaction system was reacted, and dynamic agitation speed preferable range is 50～350 rev/mins, and more preferably scope is 150～250 rev/mins.The particle diameter preferable range of NaA zeolite is less than 500 nanometers.

Among the present invention, in the little crystal grain NaA zeolite process of preparation,, therefore greatly reduce preparation cost, obtained little crystal grain NaA zeolite simultaneously, obtained better technical effect owing to need not adopt organic formwork agent.

Description of drawings

Fig. 1 is the XRD figure spectrum of embodiment 5 products.

Fig. 2 is the SEM figure of embodiment 5 products.

Fig. 3 is the high power SEM figure of embodiment 5 products.

From Fig. 1, shown the XRD diffraction peak of NaA zeolite clearly, shown that product has higher degree of crystallinity.Shown that from Fig. 2 product is the particle of 200～300 nanometers, granularity is more even.As can be seen from Figure 3 this annular particles is to be made of very little particle (about 50 nanometers).

The invention will be further elaborated below by embodiment.

Embodiment

Below example be to adopt commercial general reagent under the situation of no any organic additive to the present invention, the dynamic agitation hydro-thermal is synthesized further specifying that the method that successfully prepares ultra micro NaA zeolite does.Below all examples take steps into: with NaOH and 40% weight si colloidal sol mixing and stirring, add rapidly the NaAlO that is disposed ₂Solution stirs, and changes sealed vessel then over to and carry out crystallization under whipped state.The reaction system mole consists of aNa ₂O: XAl ₂O ₃: SiO ₂: dH ₂O, stirring velocity is 200 rev/mins.Reaction product is through centrifugation, and then repeatedly disperses centrifuge washing, drying.

[embodiment 1～4]

The value of a is 6.0, and the value of d is 128, and the value of X respectively is 3.0,2.5,2.0 and 1.5, reacted 5 hours down at 90 ℃, and the bright product of product XRD figure stave is the NaA zeolite, the SEM characterization result shows that zeolite granular is of a size of the NaA zeolite of 300～800 nanometers.

[embodiment 5～8]

The value of a is 6.0, the value of d is 128, the value of X is 2.5, under 60 ℃, reacted respectively successively 8 hours, 10 hours, 12 hours and 14 hours, the bright product of product XRD figure stave is the NaA zeolite, the SEM characterization result shows that the zeolite granular size range is respectively 200～300 nanometers, 200～400 nanometers, 200～500 nanometers and 300～700 nanometers, 8 hours product particle of high power SEM photo demonstration reaction is made up of the NaA nanocrystal less than 100 nanometers, wherein react 8 hours product X RD collection of illustrative plates as shown in Figure 1, SEM schemes as shown in Figure 2, high power SEM schemes as shown in Figure 3.

[embodiment 9～12]

The value of X is 2.5, and the value of d is 128, and the value of a respectively is 4.0,5.0,7.0 and 8.0, reacted 8 hours down at 60 ℃, and product XRD and SEM characterization result show that product is the NaA zeolite less than 1 micron.

[embodiment 13～16]

The value of X is 2.5, and the value of a is 6.0, and the value of d respectively is 100,200,300 and 400, reacted 10 hours down at 70 ℃, and product XRD and SEM characterization result show that product is the NaA zeolite less than 1 micron.

[embodiment 17～20]

The value of a is 6.0, and the value of d is 128, and the value of X is 2.5, and respectively successively at 55 ℃, 70 ℃, 80 ℃ and 90 ℃ were reacted 8 hours down, and product XRD and SEM characterization result show that product is the NaA zeolite less than 1 micron.

Claims

1, a kind of little crystal grain NaA prepare zeolite method is with silicon sol or the SiO that obtained by positive tetraethyl orthosilicate hydrolysis ₂Precursor is the silicon source, is the aluminium source with the sodium metaaluminate, and material molar ratio consists of aNa ₂O: XAl ₂O ₃: SiO ₂: dH ₂O, a=4～9 wherein, X=0.4～4, d=50～500 are 40～100 ℃ at crystallization temperature, crystallization time is that hydrothermal crystallizing makes particle diameter less than 1 micron NaA zeolite under 2.0～72 hours conditions.

2, according to the described little crystal grain NaA prepare zeolite method of claim 1, it is characterized in that crystallization temperature is 50～80 ℃, crystallization time is 2～20 hours.

3, according to the described little crystal grain NaA prepare zeolite method of claim 1, the value that it is characterized in that a is 5～7, and the value of X is 1.5～3.0, and the value of d is 100～300.

4, according to the described little crystal grain NaA prepare zeolite method of claim 3, the value that it is characterized in that X is 2.0～2.5.

5, according to the described little crystal grain NaA prepare zeolite method of claim 1, it is characterized in that reacting crystallization time is 5～14 hours.

6,, it is characterized in that adopting when reaction system is reacted dynamic agitation according to the described little crystal grain NaA prepare zeolite method of claim 1.

7, according to the described little crystal grain NaA prepare zeolite method of claim 6, it is characterized in that dynamic agitation speed is 50～350 rev/mins.

8, according to the described little crystal grain NaA prepare zeolite method of claim 7, it is characterized in that dynamic agitation speed is 150～250 rev/mins.

9, according to the described little crystal grain NaA prepare zeolite method of claim 1, the particle diameter that it is characterized in that the NaA zeolite is less than 500 nanometers.