CN105293516A

CN105293516A - Method for rapidly preparing ZSM-22 molecular sieve by means of seed crystal

Info

Publication number: CN105293516A
Application number: CN201510708781.4A
Authority: CN
Inventors: 方云明; 武秋颖; 黄勇; 李明瑞
Original assignee: Beijing University of Chemical Technology
Current assignee: Beijing University of Chemical Technology
Priority date: 2015-10-27
Filing date: 2015-10-27
Publication date: 2016-02-03

Abstract

The invention provides a method for rapidly preparing a ZSM-22 molecular sieve by means of a seed crystal, and belongs to the technical field of molecular sieve preparation. A ZSM-22 molecular sieve serves as the seed crystal and is added to an inorganic raw material gel solution, and the ZSM-22 molecular sieve can be obtained after short crystallization time. The method for rapidly preparing the ZSM-22 molecular sieve by means of the seed crystal has the advantages that the crystallization time is significantly shorter than that of other synthesis and preparation methods, and industrial production is facilitated; the synthesis raw materials are all inorganic raw materials, an organic template reagent is not used, and the raw materials are environmentally friendly and low in price; the product is good and stable in quality and has potential application value in some important catalytic reactions.

Description

A kind of method using crystal seed to prepare ZSM-22 molecular sieve fast

Technical field

The invention belongs to the synthesis preparation method of molecular sieve, particularly, relate to a kind of crystal seed Fast back-projection algorithm legal system that uses for the method for ZSM-22 molecular sieve.

Background technology

Zeolite molecular sieve is a kind of porous crystalline material with specific regular pore passage structure and homogeneous aperture size, its duct size is suitable with general molecular size, the thermostability of molecular sieve and hydrothermal stability are all relatively good, can siccative, sorbent material, ion-exchanger and catalyzer etc. be used as, have a wide range of applications in fields such as refining of petroleum, petrochemical complex and fine chemistries.The eighties in last century, first Mobil company of the U.S. synthesizes ZSM-22 molecular sieve, and skeleton comprises the structural framings such as five-ring, six-ring and ten-ring, has TON topological framework.The main aperture road of ZSM-22 is the oval duct of ten-ring one dimension, and be parallel to [001] direction, mean diameter is 0.45*0.54nm, without intersecting duct.ZSM-22 has excellent reactive behavior and product selectivity, therefore has good catalytic applications in fields such as alkylating aromatic hydrocarbon, hydrocracking, catalytic dewaxing, alkane aromatizations.

Generally use organic formwork agent as 1 during domestic and international synthesis ZSM-22 molecular sieve, 6 hexanediamines [US5707600, CN104671253A], quadrol [US4556477] etc., these organic formwork agents are expensive, and can produce waste water and gas in building-up process with the process of expeling template.Recently, some ZSM-22 Zeolite synthesis methods not using organic formwork agent [CN103101924A, CN104671252A, CN104370292A] are also had to report.But the crystallization time of these method ZSM-22 molecular sieves above is generally at 24 ~ 72h, and cause the generated time of ZSM-22 molecular sieve long, the utilising efficiency of crystallization device is lower.Therefore develop a kind of ZSM-22 molecular sieve that synthesizes within the shorter time to have great importance.

Summary of the invention

The object of the invention is to overcome the deficiencies in the prior art, use ZSM-22 crystal seed and do not use organic formwork agent condition under, synthesize the method for ZSM-22 molecular sieve with shorter crystallization time.

Use crystal seed Fast back-projection algorithm provided by the invention prepares the method for ZSM-22 molecular sieve, specific as follows:

Deionized water is mixed with silicon source, aluminium source and inorganic alkali source, add ZSM-22 crystal seed again to stir formation mixed gel, ageing under room temperature, mixed gel adds in crystallization device and carries out crystallization, product suction filtration, oven dry, namely obtain ZSM-22 molecular screen primary powder.

Described silicon source is the mixture of one or more in silicon sol, Silica hydrogel, methyl silicate, tetraethoxy, white carbon black, following SiO ₂that silicon source is amounted to SiO ₂use magnitude relation during metering, SiO ₂be 1:5 ~ 100 with the mol ratio of deionized water, preferred 1:10 ~ 60; Described aluminium source is the mixture of one or more in sodium aluminate, aluminium hydroxide, aluminum oxide, aluminum chloride, Tai-Ace S 150, aluminum nitrate, aluminum isopropylate, following Al ₂o ₃that aluminium source is amounted to Al ₂o ₃use magnitude relation during metering, Al ₂o ₃with SiO ₂mol ratio be 1:20 ~ 300, preferred 1:40 ~ 150; Described alkali source is one or both the mixture in potassium hydroxide, sodium hydroxide, OH corresponding in alkali source ^-with SiO ₂mol ratio be 1:1 ~ 20, preferred 1:2 ~ 10; Described ZSM-22 molecular sieve crystal seed is ZSM-22 molecular screen primary powder before roasting, H type ZSM-22 molecular sieve, NH ₄the mixture of one or more in type ZSM-22 molecular sieve, Na type ZSM-22 molecular sieve, SiO ₂be 1:0.01 ~ 0.2 with the mass ratio of ZSM-22 molecular sieve crystal seed, preferred 1:0.02 ~ 0.1.The digestion time of ageing under described room temperature is 1 ~ 72h; The temperature of described crystallization is 105 ~ 250 DEG C, preferably 120 ~ 200 DEG C; The time of crystallization is 10 ~ 239min, preferably 30 ~ 150min; Crystallization can be static crystallization, also can be dynamic crystallization; The reactor of crystallization can be batch tank reactor, also can be the reactor of other forms such as continuous tank reactor, semicontinuous tank reactor, tubular reactor.

The present invention can produce beneficial effect and comprise:

By the ZSM-22 molecular sieve of technical solution of the present invention Fast back-projection algorithm high-crystallinity under the condition using crystal seed.Compared with prior art, in the present invention, the crystallization time of crystallization significantly reduces, improve the utilising efficiency of reactor, can enhance productivity in the industrial production and reduce production cost, and can be implemented in multi-form reactor crystallization occurs; Technical solution of the present invention does not use organic formwork agent, environmental friendliness, does not produce organic liquid waste waste gas, and three-protection design cost is little, and production cost can significantly reduce; Product degree of crystallinity and the purity of the technology of the present invention acquisition are high, have regular structure, larger specific surface area and good catalytic reaction activity, have good application prospect in refining of petroleum, petrochemical complex and field of fine chemical.

Accompanying drawing explanation

Fig. 1 is the XRD figure that embodiment 1 uses the ZSM-22 molecular sieve of crystal seed Fast back-projection algorithm.

Fig. 2 is that embodiment 1 uses the SEM of the ZSM-22 molecular sieve of crystal seed Fast back-projection algorithm to scheme.

Fig. 3 is the XRD figure that embodiment 2 uses the ZSM-22 molecular sieve of crystal seed Fast back-projection algorithm.

Fig. 4 is the XRD figure that comparative example 1 uses the ZSM-22 molecular sieve of crystal seed Fast back-projection algorithm.

Embodiment

Embodiment is used to provide a further understanding of the present invention and explain illustrate, but is not construed as limiting the invention.

Concrete methods of realizing of the present invention:

Deionized water is mixed with silicon source, aluminium source and inorganic alkali source, add ZSM-22 crystal seed again to stir formation mixed gel, ageing under room temperature, mixed gel is preheated to crystallization temperature, add in crystallization device and carry out crystallization, product suction filtration, oven dry, namely obtain ZSM-22 molecular screen primary powder.

Further describe the present invention by the following examples, but embodiment is not intended to limit the present invention, any pro forma restriction is not done to the present invention.Every content not departing from technical solution of the present invention, the simple modification done following examples according to technological reality of the present invention, equivalent variations and modification, all still belong within the scope of technical solution of the present invention.

Embodiment 1

By 1.12gKOH and 0.20gAl ₂o ₃be dissolved in 90g deionized water, after stirring clarification, add 18.54g silicon sol (SiO ₂content is 32.4%), at room temperature continuing to stir until form uniform silicon-aluminum sol, finally adding 0.12g (for adding SiO ₂2% of quality) ZSM-22 molecular sieve stirring, the mol ratio SiO of reaction raw materials ₂: Al ₂o ₃: OH ^-: H ₂o is 1:0.02:0.2:50.Mixing raw material is still aging 8h at room temperature, and be then transferred in the stainless steel cauldron of band polytetrafluoro liner, 150 DEG C of static crystallization 30min, product suction filtration is dried and obtained sintetics.

As shown in Figure 1, through its structure of X diffraction analysis be ZSM-22 zeolite molecular sieve.

As shown in Figure 2, can find out that the purity of product is higher by stereoscan photograph.

Embodiment 2

According to the proportioning raw materials of embodiment 1 and ageing, crystallization condition synthesis ZSM-22 molecular sieve, unlike, the time of crystallization is 10min.According to the method for the present embodiment, the XRD figure of sintetics is shown in Fig. 3.

Embodiment 3

According to the proportioning raw materials of embodiment 1 and ageing, crystallization condition synthesis ZSM-22 molecular sieve, unlike, the time of crystallization is 150min.According to the method for the present embodiment, through XRD analysis, it consists of ZSM-22 molecular sieve to sintetics.

Embodiment 4

According to the proportioning raw materials of embodiment 1 and ageing, crystallization condition synthesis ZSM-22 molecular sieve, unlike, crystallization adopts dynamic crystallization method, and mixing speed is 60rmp.According to the method for the present embodiment, through XRD analysis, it consists of ZSM-22 to sintetics.

Embodiment 5

According to ageing and the crystallization condition synthesis ZSM-22 molecular sieve of embodiment 1, unlike, feed molar proportioning SiO ₂: Al ₂o ₃: OH ^-: H ₂o is 1:0.005:0.2:50.According to the method for the present embodiment, through XRD analysis, it consists of ZSM-22 molecular sieve and crystobalite to sintetics.

Comparative example 1

According to the proportioning raw materials of embodiment 1 and ageing, crystallization condition synthesis ZSM-22 molecular sieve, unlike, the time of crystallization is 24h.According to the method for this comparative example, the XRD figure of sintetics is shown in Fig. 4.

Claims

1. use crystal seed Fast back-projection algorithm to prepare the method for ZSM-22 molecular sieve, it is characterized in that, specific as follows:

2. according to the method for claim 1, it is characterized in that, described silicon source is the mixture of one or more in silicon sol, Silica hydrogel, methyl silicate, tetraethoxy, white carbon black;

Described aluminium source is the mixture of one or more in sodium aluminate, aluminium hydroxide, aluminum oxide, aluminum chloride, Tai-Ace S 150, aluminum nitrate, aluminum isopropylate;

Described alkali source is one or both the mixture in potassium hydroxide, sodium hydroxide.

3. according to the method for claim 2, it is characterized in that, silicon source is with SiO ₂meter, aluminium source is with Al ₂o ₃meter, alkali source is with OH ^-meter, SiO ₂be 1:5 ~ 100 with the mol ratio of deionized water, Al ₂o ₃with SiO ₂mol ratio be 1:20 ~ 300, OH corresponding in alkali source ^-with SiO ₂mol ratio be 1:1 ~ 20.

4. according to the method for claim 3, it is characterized in that, SiO ₂be 1:10 ~ 60 with the mol ratio of deionized water, Al ₂o ₃with SiO ₂mol ratio be 1:40 ~ 150, OH corresponding in alkali source ^-with SiO ₂mol ratio be 1:2 ~ 10.

5. according to the method for claim 1, it is characterized in that, described ZSM-22 molecular sieve crystal seed is ZSM-22 molecular screen primary powder before roasting, H type ZSM-22 molecular sieve, NH ₄the mixture of one or more in type ZSM-22 molecular sieve, Na type ZSM-22 molecular sieve.

6. according to the method for claim 1, it is characterized in that, silicon source is with SiO ₂meter, SiO ₂be 1:0.01 ~ 0.2 with the mass ratio of ZSM-22 molecular sieve crystal seed.

7. according to the method for claim 6, it is characterized in that, SiO ₂be 1:0.02 ~ 0.1 with the mass ratio of ZSM-22 molecular sieve crystal seed.

8. according to the method for claim 1, it is characterized in that, the digestion time of ageing under described room temperature is 1 ~ 72h; The temperature of described crystallization is 105 ~ 250 DEG C; The time of crystallization is 10 ~ 239min.

9. according to the method for claim 8, it is characterized in that, the temperature of crystallization is 120 ~ 200 DEG C; The time of crystallization is 30 ~ 150min.

10. according to the method for claim 1, it is characterized in that, crystallization is static crystallization, or is dynamic crystallization; The reactor of crystallization is batch tank reactor, continuously tank reactor, semicontinuous tank reactor or tubular reactor.