CN106430236A

CN106430236A - Preparation method for mesoporous ZSM-5 molecular sieve

Info

Publication number: CN106430236A
Application number: CN201610848260.3A
Authority: CN
Inventors: 邓风; 刘小龙; 张展培; 周雪; 徐君; 王强; 齐国栋; 王超
Original assignee: Wuhan Institute of Physics and Mathematics of CAS
Current assignee: Wuhan Institute of Physics and Mathematics of CAS
Priority date: 2016-09-26
Filing date: 2016-09-26
Publication date: 2017-02-22
Anticipated expiration: 2036-09-26
Also published as: CN106430236B

Abstract

The invention discloses a preparation method for a mesoporous ZSM-5 molecular sieve and relates to a molecular sieve. The method comprises the following steps: (1) fully mixing and grinding a certain amount of white carbon black or silica gel, tetrapropylammonium bromide, ammonium bifluoride and aluminum sulfate, and then putting the mixed raw material after being ground into a polytetrafluoroethylene lining stainless steel reaction kettle and crystallizing for 3-5 days at 145 DEG C under a static condition; (2) moving the products obtained in the step (1) into a beaker, adding water at a certain ratio and stirring for 12 hours; (3) washing the products obtained in the step (2) with deionized water, and drying, thereby obtaining the mesoporous ZSM-5. The method provided by the invention is characterized in that the mesoporous of the ZSM-5 molecular sieve is prepared by only adding water and remained raw material for forming a solution; the preparation method is a simple and economic post-processing method; high degree of crystallinity and few defects are maintained; the mesoporous ZSM-5 molecular sieve has excellent catalytic activity and longer service life.

Description

The preparation method of mesoporous ZSM-5 molecular sieve

Technical field

The present invention relates to molecular sieve, the preparation method of more particularly, to mesoporous ZSM-5 molecular sieve.

Background technology

ZSM-5 molecular sieve（R. J Argauer, G. R Landolt, Mobil oil corp, US3702886 A, 1972）, because it has higher silica alumina ratio, unique pore passage structure, larger specific surface area and excellent heat and hydro-thermal knot Structure stability, in the petrochemical process such as the shape slective cracking of hydro carbons, alkylation, isomerization, disproportionation, catalytic dewaxing and etherificate Obtain extremely being widely applied.But be as the increasingly minimizing of petroleum resources, the increasingly increase of consumption of petroleum amount, to oil plus The catalytic efficiency of work catalyst is put forward higher requirement, and the aperture size of micro porous molecular sieve limits bigger molecule and enters its hole Road is contacted with active center, is unfavorable for reaction and the abjection of macromole, therefore synthesizes the heat that mesoporous ZSM-5 molecular sieve is instantly Point.Containing mesoporous ZSM-5 in catalytic reaction, there is mass transfer advantage, shorten diffusion within molecular sieve for the reactant molecule Path is so as to be more easily accessible to the active center of molecular sieve inner surface, thus improving the catalysis activity of material.And traditional During hydro-thermal gel synthetic ZSM-5 zeolite molecular sieve under alkalescence condition, bromination organic formwork agent need using silver oxide or from Being converted into hydroxide organic formwork agent, reaction cost increases sub- exchange column；Silicon source and silicon source hydrolytic process in alkaline solution Time-consuming very long, efficiency is low and energy consumption is larger；Simultaneously because needing to add Fluohydric acid. to introduce fluorion mineralizer, bring to reality again Test the harm in the health of personnel, therefore seeking a suitable reduces cost, raising efficiency and safer synthetic method is Very necessary

2012, Zhejiang University Xiao Fengshou professor seminar developed under a kind of direct grinding condition of no solvent by Solid raw materials The method of synthesis of molecular sieve（Xiao Fengshou etc., CN102627287）This synthetic method significantly simplify traditional Hydrothermal Synthesiss Method, improves yield, reduces production cost, has saved the energy, decreases the pollution to environment, has very big commercial Application to dive Power.

Content of the invention

The purpose of the present invention be that overcome the shortcomings of problems of the prior art and, provide a kind of reduces cost, Improve efficiency and the preparation method of safer mesoporous ZSM-5 molecular sieve.

For solving above-mentioned technical problem, the solution of the present invention is：

In traditional synthetic schemes, provide alkalescence source with ammonium salt；And be by using NH in the present invention₄HF₂Make to realize F For mineralizer（Non-alkaline synthetic method）This important synthesis path；And carry out water process after the completion of reaction, this Step plays the role of critically important for the mesoporous formation of molecular sieve.

Specifically, this method comprises the following steps：

1. a certain amount of white carbon or silica gel, 4-propyl bromide, fluohydric acid gas ammonia and aluminum sulfate octadecahydrate are sufficiently mixed grinding, Again the mixture material after grinding is put in polytetrafluoroethyllining lining stainless steel cauldron, under conditions of static state, 145 C are brilliant Change 3-5 days；

2. the product of step 1. gained is moved in beaker, plus the water of certain proportion amount, stir 12 hours；

3. the product deionized water of step 2. gained is washed, be dried, you can obtain mesoporous ZSM-5；

The mol ratio of reaction raw materials is：

White carbon：0.25 4-propyl bromide：2.0 fluohydric acid gas ammonia：(0.003-0.025) aluminum sulfate octadecahydrate；

Silica gel：0.25 4-propyl bromide：2.0 fluohydric acid gas ammonia：(0.003-0.025) aluminum sulfate octadecahydrate.

The present invention has following advantages and good effect：

1. using 4-propyl bromide organic formwork agent it is not necessary to being converted into hydroxide and have using silver oxide or ion exchange column Machine template, reactant cost reduces；

2. do not need to add Fluohydric acid. to introduce fluorion mineralizer, decrease to the harm in experimenter's health；

3. form solution simply by addition water and remaining raw material, and then manufacture the mesoporous of ZSM-5 molecular sieve, this is both simple Again economic post-processing approach is obtaining mesopore molecular sieve；

4. the mesoporous ZSM-5 zeolite molecular sieve that the present invention obtains maintains good degree of crystallinity and few defect, so possessing Preferably catalysis activity and longer service life.

Brief description

Fig. 1 a is the XRD spectra of this method sinteticses（Silicon source is white carbon, silica alumina ratio 50）,

Fig. 1 b is the XRD spectra of this method sinteticses（Silicon source is white carbon, silica alumina ratio 100）,

Fig. 1 c is the XRD spectra of this method sinteticses（Silicon source is silica gel, and silica alumina ratio is 50）,

Fig. 1 d is the XRD spectra of this method sinteticses（Silicon source is silica gel, and silica alumina ratio is 100）；

Fig. 2 a is the SEM photograph of this method sinteticses（Silicon source is white carbon, silica alumina ratio 50）,

Fig. 2 b is the SEM photograph of this method sinteticses（Silicon source is white carbon, silica alumina ratio 100）,

Fig. 2 c is the SEM photograph of this method sinteticses（Silicon source is silica gel, silica alumina ratio 50）,

Fig. 2 d is the SEM photograph of this method sinteticses（Silicon source is silica gel, silica alumina ratio 100）.

Abbreviation

XRD：X-ray diffraction；

SEM：Scanning electron microscope.

Specific embodiment

Describe in detail with embodiment below in conjunction with the accompanying drawings：

Embodiment 1：4-propyl bromide is directed agents, and silica gel is silicon source, and sial rate of charge is 50, solventless method solid phase synthesis ZSM-5 molecular sieve

1. 1.2g silica gel, 1.33g 4-propyl bromide, 2.28g fluohydric acid gas ammonia are weighed successively, 0.133g aluminum sulfate octadecahydrate is abundant Mixed grinding, then the mixture material after grinding is put in polytetrafluoroethyllining lining stainless steel cauldron, in static condition Under, 145 C crystallization 3 days；

The product that 1. 2. step walk gained moves in beaker, plus the water of 50ml, stirs 12 hours；

3. by step, 2. products therefrom deionized water is washed, and is dried, you can obtain mesoporous ZSM-5；

The mol ratio of reaction raw materials is：

Silica gel：0.25 4-propyl bromide：2.0 fluohydric acid gas ammonia：0.01 aluminum sulfate octadecahydrate.

It is ZSM-5 zeolite molecular sieve through its structure of X-ray diffraction analysis, and be can be seen that by stereoscan photograph To be typical ZSM-5 pattern crystal grain, such as Fig. 1 a, Fig. 2 a.

Embodiment 2：4-propyl bromide is directed agents, and silica gel is silicon source, and sial rate of charge is 100, solventless method solid phase Synthesis ZSM-5 molecular sieve

1. 1.2g silica gel, 1.33g 4-propyl bromide, 2.28g fluohydric acid gas ammonia are weighed successively, 0.066g aluminum sulfate octadecahydrate is abundant Mixed grinding, then the mixture material after grinding is put in polytetrafluoroethyllining lining stainless steel cauldron, in static condition Under, 145 DEG C of crystallization 3 days；

3. by step, 2. products therefrom deionized water is washed, and is dried, you can obtain mesoporous ZSM-5；The rubbing of reaction raw materials You are at ratio：

Silica gel：0.25 4-propyl bromide：2.0 fluohydric acid gas ammonia：0.005 aluminum sulfate octadecahydrate.

It is ZSM-5 zeolite molecular sieve through its structure of X-ray diffraction analysis, and be can be seen that by stereoscan photograph To be typical ZSM-5 pattern crystal grain, such as Fig. 1 b, Fig. 2 b.

Embodiment 3：4-propyl bromide is directed agents, and white carbon is silicon source, and sial rate of charge is 50, solventless method solid phase Synthesis ZSM-5 molecular sieve

1. 1.2g white carbon, 1.33g 4-propyl bromide, 2.28g fluohydric acid gas ammonia are weighed successively, 0.133g aluminum sulfate octadecahydrate is filled Divide mixed grinding, then the mixture material after grinding is put in polytetrafluoroethyllining lining stainless steel cauldron, in static bar Under part, 145 DEG C of crystallization 3 days

2. the product of step 1. gained is moved in beaker, plus 50ml water, stir 12 hours

3. by step, 2. products therefrom deionized water is washed, and is dried, you can obtain mesoporous ZSM-5, the rubbing of reaction raw materials You are at ratio：

White carbon：0.25 4-propyl bromide：2.0 fluohydric acid gas ammonia：0.01 aluminum sulfate octadecahydrate.

It is ZSM-5 zeolite molecular sieve through its structure of X-ray diffraction analysis, and be can be seen that by stereoscan photograph To be typical ZSM-5 pattern crystal grain, such as Fig. 1 c, Fig. 2 c.

Embodiment 4：4-propyl bromide is directed agents, and white carbon is silicon source, and sial rate of charge is 100, and solventless method is solid It is combined to ZSM-5 molecular sieve

1. 1.2g white carbon, 1.33g 4-propyl bromide, 2.28g fluohydric acid gas ammonia are weighed successively, 0.066g aluminum sulfate octadecahydrate is filled Divide mixed grinding, then the mixture material after grinding is put in polytetrafluoroethyllining lining stainless steel cauldron, in static bar Under part, 145 DEG C of crystallization 3 days

2. the product of step 1. gained is moved in beaker, plus the water of 50ml, stir 12 hours

3. by step, 2. products therefrom deionized water is washed, be dried, you can obtain mesoporous ZSM-5 reaction raw materials mole Than for：

SiO₂（White carbon）：0.25 4-propyl bromide：2.0 fluohydric acid gas ammonia：0.005 aluminum sulfate octadecahydrate

It is ZSM-5 zeolite molecular sieve through its structure of X-ray diffraction analysis, and be can be seen that by stereoscan photograph and to obtain It is typical ZSM-5 pattern crystal grain, such as Fig. 1 d, Fig. 2 d.

Claims

1. a kind of preparation method of mesoporous ZSM-5 molecular sieve is it is characterised in that comprise the following steps：

The mol ratio of reaction raw materials is：