CN103787350A - Divalent metal atom modified molecular sieve and preparation method thereof - Google Patents
Divalent metal atom modified molecular sieve and preparation method thereof Download PDFInfo
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- CN103787350A CN103787350A CN201210434217.4A CN201210434217A CN103787350A CN 103787350 A CN103787350 A CN 103787350A CN 201210434217 A CN201210434217 A CN 201210434217A CN 103787350 A CN103787350 A CN 103787350A
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Abstract
The invention discloses a divalent metal atom modified molecular sieve and a preparation method thereof. The preparation method is a two-step method which comprises the following steps: performing sufficient ion exchange on a hydrogen type or sodium type molecular sieve and divalent metal salt through a solid ion exchange method; and treating the molecular sieve after the exchange with water vapor to obtain the divalent metal atom modified molecular sieve, wherein the surface of the obtained divalent metal atom modified molecular sieve only contains mutually isolated bridge type hydroxyl groups, no interaction is generated between the centers of B acids, and the surface acid strength is simplex. The invention is used in the field of catalyst preparation and application.
Description
Technical field
The present invention relates to a kind of molecular sieve and preparation method thereof, is more specifically a kind of divalent metal atom modified molecular screen and preparation method thereof, belongs to catalyzer preparation and application field.
Background technology
Molecular sieve is a kind of of great value catalytic material, in various petrochemical complex catalysis especially acid-base catalysis, has the vital role can not be substituted.Molecular sieve is as a kind of catalytic material, its activity in most of catalytic reaction process comes from dissimilar acid site, its surface, these acid sites can roughly be divided into the L acid site of carrying protogenic B acid site and accept electron pair, in addition, different because of surface tissue and surrounding environment, the strength of acid in various acid sites also there are differences.
For acid Si-Al molecular sieve, its surperficial sial bridge hydroxyl group the most easily provides proton, is main source, B acid site.Many petrochemical complex catalyzed reactions, as reactions such as hydrocarbon catalytic pyrolysiss, its catalytic active center is considered to the B acid site of certain strength.For making catalyzer there is good reactive behavior and selectivity, conventionally to carry out modification to molecular sieve, modify with effects on surface, make its surface acid center possess suitable intensity and concentration distribution.Atoms metal modification is a kind of important surface modification modifying method, and the method can be described as conventionally: by ion exchange process, atoms metal replaces the hydrogen atom on bridge hydroxyl group, to realize the effect that reduces or eliminates surperficial B acid site.But this modification comes with some shortcomings conventionally: nearest studies confirm that, the bridge hydroxyl group on molecular sieve surface, it is B acid site, be generally occurring, the proximity of bridge hydroxyl group makes to produce each other interaction, and affect thus the intensity in B acid site, meanwhile, the bridge hydroxyl group of this paired appearance also makes exchanged atoms metal be present in molecular sieve with bivalent ions state.Molecular sieve after metal ion exchanged modification, surface B acid site will by non-selectivity eliminate or reduce, intensity also can because of exchange modification change.In the time that exchange degree is lower, will there is paired bridge hydroxyl group and divalent-metal ion in molecular sieve surface simultaneously; After hydrogen atom is by complete exchange, the B acid site on surface is by completely dissolve, and catalyzer is by loss of catalytic activity.These microtextures are all unfavorable for that catalyzer has good catalytic effect.
Summary of the invention
The invention discloses a kind of divalent metal atom modified molecular screen and preparation method thereof, aim to provide a kind of divalent metal atom modified molecular screen with unique surface structure and preparation method thereof, on atomic level, only there is isolated ol group in molecular sieve surface, what close on mutually with it is the hydroxyl being connected with divalent metal atom, and without the bridge hydroxyl group occurring in pairs, surperficial B acid site is evenly distributed, intensity is single.
The present invention adopts following technical scheme to realize:
Product technology scheme of the present invention is: a kind of divalent metal atom modified molecular screen, there is special surface hydroxyl distributed architecture, it is characterized by, on atomic level, bridge hydroxyl group as the molecular sieve surface in B acid site is adjacent to one another with the hydroxyl being connected on divalent metal atom, closes on relation, in other words as not producing interactional space between the bridge hydroxyl group in B acid site, only there is isolated ol group in molecular sieve surface, and without the bridge hydroxyl group occurring in pairs.
One or more in the present invention in the preferred BETA of the type of indication molecular sieve, L, MAZ, MFI, FER, MOR, Y zeolite, atoms metal is one or more in divalent alkaline-earth metal Be, Mg, Ca, Sr, Ba preferably.
Preparation method's technical scheme of the present invention is: Hydrogen or sodium type molecular sieve are sieved as parent molecule, prepare by two-step approach, the first step, Hydrogen or sodium type molecular sieve and divalent metal salt are carried out to sufficient ion-exchange by solid ionic exchange process, second step is processed molecular sieve after exchange between 100 ℃ to 200 ℃ with water vapour.Below this technical scheme is further described.
The first step, carries out sufficient ion-exchange with divalent metal salt by solid ionic exchange process by Hydrogen or sodium type parent molecule sieve.Solid ionic is exchanged for known technology; its process is: Hydrogen or sodium type parent molecule sieve are evenly mixed with exchanged metallic compound; under atmosphere, vacuum or protection of inert gas, carry out solid state reaction; some solid state reactions at high temperature have better exchange effect, as 300～400 ℃.
The preferred vacuum environment of solid ionic exchange process relating in the present invention, parent molecule sieves one or more in BETA, L, MAZ, MFI, FER, MOR, the Y molecular sieve of preferred Hydrogen, one or more in the preferred divalent alkaline-earth metal muriate of exchanged metal salt compound or divalent alkaline-earth metal nitrate, this solid state reaction process will obtain the divalent-metal ion exchange molecular sieve of high exchange degree, proton or Na on parent molecule sieve skeleton frame
+by completely or approach and replaced by divalent metal atom completely.
Reaction process can be expressed as:
In chemical reaction equilibrium equation, M is divalent metal, as: Mg
2+, Ca
2+deng; A is univalent anion, as: NO
3 -, Cl
-deng; Z is monovalence framework of molecular sieve structure; A is molecule mole number.
Second step is processed the molecular sieve after solid ionic exchange between 100 ℃ to 200 ℃ with water vapour.Its treating processes is: between 100 ℃ to 200 ℃, the divalent metal exchange molecular sieve of the first step gained is contacted with the water vapour under certain pressure, this pressure can be 100Pa～1kPa, then modified molecular screen sample is carried out to vacuum-treat.
Reaction process can be expressed as:
Because the present invention adopts above-mentioned steps, by the first step solid ionic permutoid reaction, divalent metal atom replaces two protons and exchanged to molecular sieve adjacent to one another, it is that bridge hydroxyl group recovers again that the steam treatment of second step makes the B acid site of molecular sieve, produce a hydroxyl being directly connected with divalent metal atom simultaneously, therefore, molecular sieve surface is bridge hydroxyl group appearance adjacent to one another on can not having living space, B acid site can not occur in pairs, thereby isolated bridge hydroxyl group is only contained on the divalent metal modified molecular screen surface of gained, between B acid site, will can not produce interaction.
Beneficial effect of the present invention can be illustrated by the characterization result of in-situ ft-ir and solid state nmr, as accompanying drawing 1, shown in accompanying drawing 2 and accompanying drawing 3.
Prepare the atom modified ZSM-5 molecular sieve of Ca with the step of method described in embodiment 1.Use the means of in-situ ft-ir respectively parent molecule sieve, solid ionic clearing house to be obtained to sample, and the finished product characterize, infrared spectrum gathers under the vacuum condition of 500 ℃, the results are shown in accompanying drawing 1.In Fig. 1, curve A is the infrared spectrum of parent molecule sieve, and curve B is the infrared spectrum of parent molecule sieve after the exchange of calcium ion solid ionic, curve C be through the exchange of calcium ion solid ionic and after steam treatment the infrared spectrum of sample.Result shows, the characteristic infrared vibration peak that characterizes bridge hydroxyl group on parent molecule sieve infrared spectra and be B acid site (is positioned at 3610 cm
-1near) after solid ionic exchange, disappearing, show the H on parent molecule sieve
+by complete exchange; After exchange, sample is after steam treatment, and bridge hydroxyl group vibration peak (is positioned at 3610 cm
-1near) reappear, show to have formed after modification the B acid site of new homogeneous.
Prepare the atom modified ZSM-5 molecular sieve of Ca with the step of method described in embodiment 1.Use the means of pyridine adsorption infrared spectra respectively parent molecule sieve, solid ionic clearing house to be obtained to sample, and the finished product characterize: sample is carried out under the vacuum condition of 500 ℃ to pre-treatment, at room temperature Adsorption of Pyridine, and in 200 ℃ of vacuum-treat, to remove physical adsorption pyridine, infrared spectrum gathers under the vacuum condition of 200 ℃, the results are shown in accompanying drawing 1.In Fig. 2, curve D is the infrared spectrum of parent molecule sieve Adsorption of Pyridine, curve E is the infrared spectrum of parent molecule sieve Adsorption of Pyridine after the exchange of calcium ion solid ionic, curve F be through the exchange of calcium ion solid ionic and after steam treatment the infrared spectrum of sample Adsorption of Pyridine.Result demonstration, the absorption band that characterizes B acid site on parent molecule sieve infrared spectra (is positioned at 1540 cm
-1near) after solid ionic exchange, disappearing, show the H on parent molecule sieve
+by complete exchange; After exchange, sample is after steam treatment, and the absorption band in B acid site (is positioned at 1540 cm
-1near) reappear, show to have formed after modification the B acid site of new homogeneous.
Prepare the atom modified ZSM-5 molecular sieve of Mg with the step of method described in embodiment 4, use the means of solid state nmr to characterize products obtained therefrom, sample is processed and is also encapsulated for 3 hours through 500 ℃, carries out solid state nmr
1h composes test, the results are shown in accompanying drawing 3.The chemical shift peak that is positioned at 3.9 ppm in figure characterizes molecular sieve surface bridge hydroxyl group, and the chemical shift peak that is positioned at 1.6 ppm characterizes molecular sieve surface silanol group, and the chemical shift peak that is positioned at 0.2 ppm characterizes the hydroxyl that molecular sieve surface is connected with magnesium atom.Above result shows the hydroxyl that molecular sieve surface exists bridge hydroxyl group simultaneously and is connected with magnesium atom, and two kinds of hydroxyls are spatially adjacent to one another.
Accompanying drawing explanation
Fig. 1 is the infrared spectrum of the molecular sieve modified front and back of HZSM-5, infrared spectrum gathers under the vacuum condition of 500 ℃, in Fig. 1, curve A is the infrared spectrum of parent molecule sieve, curve B is the parent molecule sieve infrared spectrum after the exchange of calcium ion solid ionic, curve C be through the exchange of calcium ion solid ionic and after steam treatment the infrared spectrum of sample;
Fig. 2 is the infrared spectrum of the molecular sieve modified front and back of HZSM-5 Adsorption of Pyridine, infrared spectrum gathers under the vacuum condition of 200 ℃, in Fig. 2, curve D is the infrared spectrum of parent molecule sieve Adsorption of Pyridine, curve E is the infrared spectrum of parent molecule sieve Adsorption of Pyridine after the exchange of calcium ion solid ionic, curve F be through the exchange of calcium ion solid ionic and after steam treatment the infrared spectrum of sample Adsorption of Pyridine;
Fig. 3 is the solid state nmr of preparing gained magnesium ion modified zsm-5 zeolite according to the inventive method
1h spectrum, sample is processed and is also encapsulated for 3 hours through 500 ℃, carries out solid state nmr
1h composes test.
Embodiment
Below, by reference to the accompanying drawings and specific embodiment, the X kind embodiment of invention is further described.
Embodiment 1
By HZSM-5 molecular sieve and CaCl
2be placed at room temperature abundant mixed grinding 1 day of ball mill according to Ca/Al than the ratio of 1:1, the sample after mixed grinding is processed 4 hours under 400 ℃, vacuum condition; Sample is cooled to 150 ℃, imports the water vapour of 1kPa, balance 3 minutes, then vacuum-treat 2 hours.Obtain divalent metal atom modified molecular screen.
By HY molecular sieve and BaCl
2be placed at room temperature abundant mixed grinding 1 day of ball mill according to Ba/Al than the ratio of 0.5:1, the sample after mixed grinding is processed 4 hours under 400 ℃, vacuum condition; Sample is cooled to 100 ℃, imports the water vapour of 100Pa, balance 3 minutes, then vacuum-treat 2 hours.Obtain divalent metal atom modified molecular screen.
Embodiment 3
By HBETA molecular sieve and BeCl
2be placed at room temperature abundant mixed grinding 1 day of oscillating mill according to Be/Al than the ratio of 0.5:1, the sample after mixed grinding was 400 ℃ of roastings 4 hours; Sample, 200 ℃ of vacuum-treat 4 hours, is imported to the water vapour of 100Pa, balance 3 minutes, then vacuum-treat 2 hours.Obtain divalent metal atom modified molecular screen.
By HZSM-5 molecular sieve and anhydrous MgCl
2be placed at room temperature abundant mixed grinding 1 day of ball mill according to Mg/Al than the ratio of 0.5:1, the sample after mixed grinding is processed 4 hours under 300 ℃, vacuum condition; Sample is cooled to 150 ℃, imports the water vapour of 1kPa, balance 2 minutes, 150 ℃ of vacuum-treat 2 hours.Obtain divalent metal atom modified molecular screen.
Embodiment 5
By HMOR molecular sieve and SrCl
2be placed at room temperature abundant mixed grinding 1 day of ball mill according to Sr/Al than the ratio of 0.5:1, the sample after mixed grinding is processed 4 hours under 400 ℃, vacuum condition; Sample is cooled to 100 ℃, imports the water vapour of 100Pa, balance 3 minutes, then vacuum-treat 2 hours.Obtain divalent metal atom modified molecular screen.
The foregoing is only better possible embodiments of the present invention; not thereby limit to the scope of the claims of the present invention; feature of the present invention only relates to structure, function and modification thereof and the modification in B acid site, molecular sieve surface, but the structure generation in the other types acid site simultaneously causing according to the present invention's method and variation will be contained in protection scope of the present invention.
Claims (10)
1. a divalent metal atom modified molecular screen, it is characterized in that, on atomic level, bridge hydroxyl group as the molecular sieve surface in B acid site is adjacent to one another with the hydroxyl being connected on divalent metal atom, closes on relation as not producing interactional space between the bridge hydroxyl group in B acid site.
2. divalent metal atom modified molecular screen as claimed in claim 1, is characterized in that, the type of described molecular sieve is one or more in BETA, L, MAZ, MFI, FER, MOR, Y zeolite.
3. divalent metal atom modified molecular screen as claimed in claim 1, is characterized in that, described atoms metal is one or more in divalent alkaline-earth metal Be, Mg, Ca, Sr, Ba.
4. a divalent metal atom modified molecular screen preparation method, comprises the following steps:
The first step, carries out sufficient ion-exchange by Hydrogen or sodium type molecular sieve and divalent metal salt by solid ionic exchange process,
Second step is processed molecular sieve after exchange between 100 ℃ to 200 ℃ with water vapour.
5. divalent metal atom modified molecular screen preparation method as claimed in claim 4, its feature in, in the first step, described ion-exchange reaction temperature is 300～400 ℃.
6. divalent metal atom modified molecular screen preparation method as claimed in claim 4, is characterized in that, described in
gustate ion-exchange is in vacuum environment.
7. divalent metal atom modified molecular screen preparation method as claimed in claim 4, is characterized in that, in second step, between 100 ℃ to 200 ℃, processes with water vapour.
8. divalent metal atom modified molecular screen preparation method as claimed in claim 4, is characterized in that, in second step, water vapour pressure can be 100Pa～1kPa.
9. divalent metal atom modified molecular screen preparation method as claimed in claim 4, is characterized in that, after second step, then carries out vacuum-treat.
10. divalent metal atom modified molecular screen preparation method as claimed in claim 4, it is characterized in that, in the first step, described hydrogen type molecular sieve is one or more in BETA, L, MAZ, MFI, FER, MOR, the Y molecular sieve of Hydrogen, and described metal-salt is one or more in divalent alkaline-earth metal muriate or divalent alkaline-earth metal nitrate.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108463285A (en) * | 2015-11-24 | 2018-08-28 | 巴斯夫公司 | Fluidized catalytic cracking catalyst for improving butylene yield |
| CN110498424A (en) * | 2018-05-16 | 2019-11-26 | 中国石油化工股份有限公司 | A kind of method that Y molecular sieve is modified |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN85100324A (en) * | 1985-04-01 | 1986-08-06 | 中国石油化工总公司抚顺石油化工研究院 | Distillate Hydrodewaxing catalyst and preparation method thereof |
| US5190903A (en) * | 1991-03-31 | 1993-03-02 | Uop | Low acidity Y zeolite |
| CN101723404A (en) * | 2008-10-24 | 2010-06-09 | 北京化工大学 | Method for preparing high-transition metal content molecular sieves |
-
2012
- 2012-11-02 CN CN201210434217.4A patent/CN103787350B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN85100324A (en) * | 1985-04-01 | 1986-08-06 | 中国石油化工总公司抚顺石油化工研究院 | Distillate Hydrodewaxing catalyst and preparation method thereof |
| US5190903A (en) * | 1991-03-31 | 1993-03-02 | Uop | Low acidity Y zeolite |
| CN101723404A (en) * | 2008-10-24 | 2010-06-09 | 北京化工大学 | Method for preparing high-transition metal content molecular sieves |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108463285A (en) * | 2015-11-24 | 2018-08-28 | 巴斯夫公司 | Fluidized catalytic cracking catalyst for improving butylene yield |
| CN108463285B (en) * | 2015-11-24 | 2021-11-16 | 巴斯夫公司 | Fluid catalytic cracking catalyst for increasing butene yield |
| CN110498424A (en) * | 2018-05-16 | 2019-11-26 | 中国石油化工股份有限公司 | A kind of method that Y molecular sieve is modified |
| CN110498424B (en) * | 2018-05-16 | 2021-10-08 | 中国石油化工股份有限公司 | Method for modifying Y molecular sieve |
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