CN101462742A - Preparation of fine grain SAPO-34 molecular sieve - Google Patents
Preparation of fine grain SAPO-34 molecular sieve Download PDFInfo
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- CN101462742A CN101462742A CNA2009100676916A CN200910067691A CN101462742A CN 101462742 A CN101462742 A CN 101462742A CN A2009100676916 A CNA2009100676916 A CN A2009100676916A CN 200910067691 A CN200910067691 A CN 200910067691A CN 101462742 A CN101462742 A CN 101462742A
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Abstract
The invention relates to a method for preparing a small crystal grain SAPO-34 molecular sieve with high crystallinity and large specific surface area. The method for preparing the molecular sieve is mainly characterized in that a structure guide agent containing triethylamine and fluoride is added in the forming process of a colloid mixture; and at the same time, after an ageing process, the colloid mixture is crystallized. The SAPO-34 molecular sieve prepared by the method has the advantages of small grain diameter, large specific surface area and high crystallinity.
Description
Affiliated technical field
The claimed technical scheme of the present invention relates to the preparation method of phosphorus aluminium silicate salt (SAPO compound) molecular sieve catalyst, the specifically synthetic method of aluminium silicophosphate molecular sieve SAPO-34.
Background technology
1984, U.S. Union Carbide Corp (UCC) developed silicon aluminium phosphate series molecular sieve (SAPO-n, n representative structure model).What wherein people attracted attention the most is the SAPO-34 molecular sieve.The SAPO-34 molecular sieve is by PO
4, AlO
4And SiO
4Tetrahedron interconnects and forms; Have oval cage and three-dimensional open-framework that eight Yuans rings of oxygen constitute.The shape of eight Yuans rings of oxygen may be oval, circular or wrinkling shape, and the aperture size changes with the change of shape of eight Yuans rings of oxygen, but the aperture effective diameter remains between 0.43～0.50nm.Pore volume is 0.42cm3/g, and space symmetry group R3m belongs to trigonal system, has the structure similar with chabazite.Because of its particular structure makes its excellent performance in the MTO catalyzed reaction, the very big industrial value of having realized.
In more than 20 year of past, researcher both domestic and external was done a large amount of research to the SAPO-34 molecular sieve, and its synthetic carried out deep exploration.The method for preparing molecular sieve generally adopts hydrothermal crystallization method, and synthesis step is as follows: (1) preparation crystallization mixture.Constitute the ingredients of a mixture silicon source, aluminium source, template and deionized water are arranged.Optionally there are silicon sol, active silica or tetraethyl silicate in the silicon source; There are activated alumina, pseudo-boehmite or aluminum alkoxide in the aluminium source; Ortho-phosphoric acid is generally adopted in the phosphorus source; Template can adopt tetraethyl ammonium hydroxide, morphine beautiful jade, piperidines, triethylamine or diethylamine etc.(2) aging.The crystallization mixture is enclosed in the crystallizing kettle, at the aged at room temperature certain hour.(3) crystallization.With crystallizing kettle crystallization certain hour under the 160-220 degree, sample SAPO-34 molecular sieve is isolated in washing.Synthesis condition also is that the performance of the molecular sieve that synthesizes of very big, different synthesis condition is also different to the influence of SAPO-34 molecular sieve.Wherein the selection of template is also very crucial, and template is to play the material of structure-directing effect in crystal formation process, and main rising applies the two kinds of different effects in space and electric charge.The kind difference of template, mechanism of action difference, the condition of synthesis of molecular sieve will be variant.European patent EP 0103117 discloses the hydrothermal synthesis method of SAPO-34 molecular sieve.Its technical characterstic is to have added the template tetraethyl ammonium hydroxide in the building-up process, Isopropylamine or with the mixture of tetraethyl ammonium hydroxide and di-n-propylamine.The general crystallization time of such template synthetic SAPO-34 molecular sieve is shorter, helps generating little crystal grain, and helps generating quantity suitable strong, weak acid center; On this basis, U.S. Pat 4440871 has reported that again SAPO-34 molecular sieve synthetic improves one's methods, and it has adopted identical template substantially.It is that the synthetic cost is too high that these template prices generally compare costliness, is unfavorable for the large-scale industrial production popularization.Among China Liu people to wait CN1088483 to invent with triethylamine cheap and easy to get be that template is synthesized the SAPO-34 molecular sieve catalyst, triethylamine helps generating the SAPO-34 molecular sieve of big crystal grain and more strong acid center, but use triethylamine can reduce the synthetic cost of SAPO-34 molecular sieve catalyst significantly, and extend in the suitability for industrialized production as the template of synthetic SAPO-34 molecular sieve.
The crystal grain of the common SAPO-34 type of institute's synthetic molecular sieve is generally greater than 3000nm at present.Because crystal grain is bigger, the intensity of catalyzer is relatively poor, and the duct is longer relatively, and diffusional resistance is big, makes catalyst deactivation very fast.After zeolite crystal reduced, its surface-area increased, and shorten in the duct, thereby catalyst activity point is increased relatively, and diffusion is improved.Small crystal grain molecular sieve has relatively short orifice throat length, helps the diffusion of reactant and product, and the effective inhibited reaction degree of depth is so coke content is low.
Many investigators study the SAPO-34 type molecular sieve of synthesizing small-grain, find to add approach such as organism by optimizing synthesis condition, can increase the quantity of nucleus in the synthetic system, thereby reduce the size of institute's synthetic molecular sieve.At present, the method for the fine grain SAPO-34 molecular sieve that synthesizes mainly contains: Liu's red magnitude adopts triethylamine and tetraethyl ammonium hydroxide hybrid template, synthesizes particle diameter at the SAPO-34 of 1700-2700nm molecular sieve by controlling its ratio.USP4 adopts in 587,115 and USP4,778,666 and improves processing condition, and as high-speed stirring, low temperature becomes glue and microwave method, and its synthetic particle diameter is greatly about 500nm.Paper Chem.Mater.45 (2008) 2265 has reported one piece of method about synthesis of nano SAPO-34, the employing tetraethyl ammonium hydroxide is a template, by the adding speed of control phosphoric acid and the SAPO-34 molecular sieve that step has been synthesized average 200nm, shown excellent physical and chemical performance.These methods or the expensive template tetraethyl ammonium hydroxide of employing, or building-up process complex process, and the synthetic cost increases.
Summary of the invention
The preparation method who the purpose of this invention is to provide a kind of SAPO-34 molecular sieve makes the SAPO-34 molecular sieve particle diameter that obtains little, the degree of crystallinity height.
The preparation method of small particle size of the present invention, high-crystallinity SAPO-34 molecular sieve, the formation, the colloid admixture crystallization steps that comprise colloid admixture, be added with structure directing agent and fluoride compound in the colloid admixture forming process, the colloid admixture crystallization is preceding earlier through a weathering process simultaneously.Structure directing agent adopts relatively inexpensive triethylamine, and its add-on is 2.5-3.0 of an aluminum oxide molar weight.Fluoride compound is hydrogen fluoride, Neutral ammonium fluoride and Sodium Fluoride, and optimal selection is a Neutral ammonium fluoride, and its optimal addn is the 3-10% of add aluminum oxide molar weight.
Synthetic ratio of the present invention is: P
2O
5/ Al
2O
3=0.83-1.25, SiO
2/ Al
2O
3=0-1.0, SiO
2/ P
2O
5=0-1.0, R/Al
2O
3=2.5-3.0 (R is the structure directing agent triethylamine), H
2O/Al
2O
3=40-60.In raw material, add fluoride compound, can regulate size, make particle diameter even, littler than the molecular particle size of prior art for preparing, can obtain the particle of 500～1500nm, and particle size distribution range is narrow.
Among the preparation method of the present invention, colloid admixture is preferably first through weathering process before crystallization.Weathering process can improve the degree of crystallinity of molecular sieve.The condition of weathering process is: 80-130 ℃ of aging temperatures, digestion time 2-12 hours, the best are 110 ℃ and wore out 2 hours.
After aging, colloid admixture carries out crystallization again, and the condition of crystallization can be with the technology of existing report, and preferred condition is: crystallization temperature is 180-205 ℃, constant temperature 20-60 hours, and the best is 200 ℃ of crystallization 24 hours.
After the crystallization, sample obtains the SAPO-34 molecular screen primary powder through washing, oven dry.
The concrete preparation process of the present invention is as follows:
1, the preparation of colloidal compound: at first the water of adding with aluminium source material and 1/2 mixed in reactor about 10 minutes, under agitation the aqueous solution of adding with phosphoric acid and 1/2 adds, after mixing 2 hours, add silicon-containing material again, stir, add directed agents and fluoride compound again, after fully stirring, be the reaction mixture for the treatment of crystallization.
2, with the reactor sealing, be warmed up to 80-130 ℃ of constant temperature 2-12 hour and wear out.
3, be warmed up to 180-205 ℃ again, thermostatic crystallization 20-60 hour, complete up to crystallization.
4, solid is separated with mother liquor, through deionized water wash for several times, and dry under 110 ℃, promptly get the former powder SAPO-34 of moulding molecular sieve.
5, the former powder of synthesis type is Hydrogen SAPO-34 molecular sieve through 550 ℃ of roastings 6 hours, can be used as an acidic catalyst and uses.
The SAPO-34 molecular sieve that the present invention makes, particle diameter is even, can access that (500～1500nm), specific surface area is big than the little SAPO-34 molecular sieve of prior art particle diameter.Thereby improved the performance of molecular sieve, in the MTO reaction, shown excellent catalytic performance.
Description of drawings
Fig. 1. the sample XRD spectra of the embodiment of the invention 1;
Fig. 2. the embodiment of the invention 7,8,9 sample XRD spectra;
Fig. 3. the embodiment of the invention 7,10,13 sample XRD spectra;
Fig. 4. the embodiment of the invention 7,11,12 sample XRD spectra;
Fig. 5. sample transmission electron microscope (TEM) figure of the embodiment of the invention 7
Embodiment
Embodiment 1.
The raw material pseudo-boehmite (is contained Al
2O
367.4%wt) 5.50g joins in the 70ml synthesis reactor, adds deionized water 16ml again, stirs.Under agitation add phosphoric acid and (contain H
3PO
485%wt) 8.30g and deionized water 16ml.About 2 hours of vigorous stirring adds silicon sol again and (contains SiO
230%wt) 5.76g adds triethylamine 10.93g, and stir about 2 hours is up to forming even colloid.Reactor is put into baking oven, be warming up to 110 ℃, constant temperature 2 hours is warming up to 200 ℃ then, constant temperature 24 hours after the cooling, is separated solid from mother liquor, solid at 110 ℃ of following air dryings, obtains the SAPO-34 molecular screen primary powder with deionized water wash for several times.Its degree of crystallinity and particle diameter are shown in Table 1.
In embodiment 1, only the amount with the silicon sol that adds has 5.76g to become 2.88g, and all the other components and operation are constant, have obtained pure phase SAPO-34 molecular screen primary powder.Through 550 ℃ of roastings 6 hours, obtain the SAPO-34 molecular sieve.Its degree of crystallinity and particle diameter are shown in Table 1.
Embodiment 3.
In embodiment 1, only the amount with the silicon sol that adds has 5.76 to bring up to 8.64g, and all the other components and operation are constant, have obtained pure phase SAPO-34 molecular screen primary powder.Through 550 ℃ of roastings 6 hours, obtain the SAPO-34 molecular sieve.Its degree of crystallinity and particle diameter are shown in Table 1.
Embodiment 4.
In embodiment 1, synthesis reactor directly is warming up to 200 ℃ in baking oven, constant temperature 24 hours, and all the other components and operation are constant, have obtained pure phase SAPO-34 molecular screen primary powder.Through 550 ℃ of roastings 6 hours, obtain the SAPO-34 molecular sieve.Its degree of crystallinity and particle diameter are shown in Table 1.
In embodiment 2, synthesis reactor directly is warming up to 200 ℃ in baking oven, constant temperature 24 hours, and all the other components and operation are constant, have obtained pure phase SAPO-34 molecular screen primary powder.Through 550 ℃ of roastings 6 hours, obtain the SAPO-34 molecular sieve.Its degree of crystallinity and particle diameter are shown in Table 1.
Embodiment 6.
In embodiment 3, synthesis reactor directly is warming up to 200 ℃ in baking oven, constant temperature 24 hours, and all the other components and operation are constant, have obtained pure phase SAPO-34 molecular screen primary powder.Through 550 ℃ of roastings 6 hours, obtain the SAPO-34 molecular sieve.Its degree of crystallinity and particle diameter are shown in Table 1.
Table 1
| Embodiment | 1 | 2 | 3 | 4 | 5 | 6 |
| Degree of crystallinity % | 105 | 100 | 95 | 100 | 98 | 90 |
| Particle diameter nm | 3000 | 3500 | 3750 | 4500 | 5000 | 4000 |
As seen from Table 1: in the SAPO-34 sieve synthesis procedure, colloid admixture after burin-in process, improved synthesize the degree of crystallinity of SAPO-34 molecular sieve, suitably reduced particle diameter.
In embodiment 1, just add the structure directing agent triethylamine again after, add the 0.04g Neutral ammonium fluoride again, all the other components and the operation constant, obtained pure phase SAPO-34 molecular screen primary powder.Through 550 ℃ of roastings 6 hours, obtain the SAPO-34 molecular sieve.Its degree of crystallinity and particle diameter are shown in Table 2.
In embodiment 1, just add the structure directing agent triethylamine again after, add the 0.08g Neutral ammonium fluoride again, all the other components and the operation constant, obtained pure phase SAPO-34 molecular screen primary powder.Through 550 ℃ of roastings 6 hours, obtain the SAPO-34 molecular sieve.Its degree of crystallinity and particle diameter are shown in Table 2.
In embodiment 1, just add the structure directing agent triethylamine again after, add the 0.12g Neutral ammonium fluoride again, all the other components and the operation constant, obtained pure phase SAPO-34 molecular screen primary powder.Through 550 ℃ of roastings 6 hours, obtain the SAPO-34 molecular sieve.Its degree of crystallinity and particle diameter are shown in Table 2.
Table 2
| Embodiment | 1 | 7 | 8 | 9 |
| Degree of crystallinity % | 105 | 110 | 100 | 95 |
| Particle diameter nm | 2500 | 1400 | 1500 | 1700 |
As can be seen from Table 2: in the SAPO-34 sieve synthesis procedure, added Neutral ammonium fluoride after, in conjunction with weathering process the particle diameter of the synthetic SAPO-34 of institute molecular sieve is diminished.
In embodiment 7, just after adding structure directing agent triethylamine and Neutral ammonium fluoride, be warming up to 80 ℃, aging 2 hours of constant temperature, all the other components and operation are constant, have obtained pure phase SAPO-34 molecular screen primary powder.Through 550 ℃ of roastings 6 hours, obtain the SAPO-34 molecular sieve.Its degree of crystallinity and particle diameter are shown in Table 3.
In embodiment 7, just after adding structure directing agent triethylamine and Neutral ammonium fluoride, be warming up to 110 ℃, aging 6 hours of constant temperature, all the other components and operation are constant, have obtained pure phase SAPO-34 molecular screen primary powder.Through 550 ℃ of roastings 6 hours, obtain the SAPO-34 molecular sieve.Its degree of crystallinity and particle diameter are shown in Table 3.
In embodiment 1, just after adding structure directing agent triethylamine and Neutral ammonium fluoride, be warming up to 110 ℃, aging 15 hours of constant temperature, all the other components and operation are constant, have obtained pure phase SAPO-34 molecular screen primary powder.Through 550 ℃ of roastings 6 hours, obtain the SAPO-34 molecular sieve.Its degree of crystallinity and particle diameter are shown in Table 3.
Embodiment 13.
In embodiment 1, just after adding structure directing agent triethylamine and Neutral ammonium fluoride, be warming up to 130 ℃, aging 6 hours of constant temperature, all the other components and operation are constant, have obtained to contain the former powder of SAPO-34 of SAPO-5 molecular sieve.Its degree of crystallinity and particle diameter are shown in Table 3.
Table 3
| |
7 | 10 | 11 | 12 |
| Degree of crystallinity % | 110 | 103 | 110 | 112 |
| Particle diameter nm | 1400 | 1500 | 1650 | 10000 |
As can be seen from Table 3: in the SAPO-34 sieve synthesis procedure, after adding an amount of Neutral ammonium fluoride, different aging temperatures and time effects crystalline phase and size, better at the degree of crystallinity and the particle diameter of 110 ℃ of down aging 6 hours synthetic SAPO-34 molecular sieves as can be seen.
Claims (5)
1, the preparation method of a kind of small particle size, high-crystallinity SAPO-34 molecular sieve, the formation, the colloid admixture crystallization steps that comprise colloid admixture, in the colloid admixture forming process, be added with structure directing agent and fluorochemical, colloid admixture carries out crystallization process more formerly through after the weathering process simultaneously.
2, preparation method according to claim 1 is characterized in that described fluorochemical is Sodium Fluoride, Neutral ammonium fluoride or hydrogen fluoride, and the best is a Neutral ammonium fluoride, and its add-on is to add 3～10% of aluminum oxide molar weight in the colloid admixture.
3, preparation method according to claim 1 is characterized in that described structure directing agent is a triethylamine, and the mol ratio of its add-on and aluminum oxide is 2.5-3.2.
4, preparation method according to claim 1 is characterized in that before the colloid admixture crystallization, and through weathering process, aging temperature is 80～130 ℃ earlier, and digestion time is 2～12 hours.
5, preparation method according to claim 1 or 5, the crystallization temperature that it is characterized in that crystallization process is 180-205 ℃, constant temperature 20-60 hour.
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Cited By (5)
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| CN103408034A (en) * | 2013-06-22 | 2013-11-27 | 天津众智科技有限公司 | Preparation method of SAPO-34 molecular sieve with small average grain diameter |
| CN105312083A (en) * | 2014-07-29 | 2016-02-10 | 孙红 | CHA-type silicon-aluminum-phosphorous molecular sieves, and preparation methods and applications thereof |
| CN109126862A (en) * | 2018-08-20 | 2019-01-04 | 中国汽车技术研究中心有限公司 | It is a kind of accelerate synthesis CHA structure molecular sieve method and its catalyst NH3-SCR reaction in application |
| CN112624139A (en) * | 2019-09-24 | 2021-04-09 | 中国石油化工股份有限公司 | SAPO-34 molecular sieve and synthetic method and application thereof |
| CN114743806A (en) * | 2022-04-27 | 2022-07-12 | 多助科技(武汉)有限公司 | Nickel-tin alloy @ nickel sulfide core-shell nanoflower composite material and preparation method and application thereof |
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2009
- 2009-01-14 CN CNA2009100676916A patent/CN101462742A/en active Pending
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103408034A (en) * | 2013-06-22 | 2013-11-27 | 天津众智科技有限公司 | Preparation method of SAPO-34 molecular sieve with small average grain diameter |
| CN103408034B (en) * | 2013-06-22 | 2015-10-28 | 天津众智科技有限公司 | The preparation method of the SAPO-34 molecular sieve that median size is little |
| CN105312083A (en) * | 2014-07-29 | 2016-02-10 | 孙红 | CHA-type silicon-aluminum-phosphorous molecular sieves, and preparation methods and applications thereof |
| CN105312083B (en) * | 2014-07-29 | 2019-03-08 | 南京开丽环保材料有限公司 | CHA type sial phosphorus molecular sieve and its preparation method and application |
| CN109126862A (en) * | 2018-08-20 | 2019-01-04 | 中国汽车技术研究中心有限公司 | It is a kind of accelerate synthesis CHA structure molecular sieve method and its catalyst NH3-SCR reaction in application |
| CN112624139A (en) * | 2019-09-24 | 2021-04-09 | 中国石油化工股份有限公司 | SAPO-34 molecular sieve and synthetic method and application thereof |
| CN112624139B (en) * | 2019-09-24 | 2022-11-04 | 中国石油化工股份有限公司 | SAPO-34 molecular sieve and synthetic method and application thereof |
| CN114743806A (en) * | 2022-04-27 | 2022-07-12 | 多助科技(武汉)有限公司 | Nickel-tin alloy @ nickel sulfide core-shell nanoflower composite material and preparation method and application thereof |
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