A kind of inorganic synthesis method for regulating the morphology of zsm-5 molecular sieves

A ZSM-5, inorganic synthesis technology, applied in the direction of crystalline aluminosilicate zeolite, borocarbonane silicone crystalline aluminosilicate zeolite, etc., can solve the problems of irreversible agglomeration of nano ZSM-5 molecular sieves, environmental pollution, increased cost, etc. , to achieve good economic and social benefits, reduce pollution, and avoid the effects of exhaust gas

Active Publication Date: 2018-09-28
SHANGHAI ADVANCED RES INST CHINESE ACADEMY OF SCI
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Problems solved by technology

[0003] In view of the shortcomings of the prior art described above, the object of the present invention is to provide an inorganic synthesis method for regulating the morphology of ZSM-5 molecular sieves, which is used to solve the problem of the need to add an organic template as a directing agent or add organic matter to solve the problem in the prior art. Regulating the morphology of molecular sieves will not only increase the cost but also cause environmental pollution. At the same time, it will cause the problem of irreversible agglomeration of nano ZSM-5 molecular sieves, and the SiO 2 / Al 2 o 3 relatively high problem

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  • A kind of inorganic synthesis method for regulating the morphology of zsm-5 molecular sieves
  • A kind of inorganic synthesis method for regulating the morphology of zsm-5 molecular sieves
  • A kind of inorganic synthesis method for regulating the morphology of zsm-5 molecular sieves

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[0032] Such as figure 1 所示,本发明涉及一种调控ZSM-5分子筛形貌的无机合成方法,其至少包括如下步骤:

[0033] 步骤(1):分别将硅源、碱源、铝源加入到纯水中,搅拌均匀,得到硅铝凝胶。

[0034] 步骤(2):向硅铝凝胶中加入分子筛形貌调节无机添加剂和沸石晶种,搅拌均匀,得到凝胶混合物。

[0035] 步骤(3):将凝胶混合物转移到密封反应釜中晶化,然后将晶化后的产物分离、干燥,得到ZSM-5分子筛。

[0036] 其中,ZSM-5分子筛的形貌适于通过调节分子筛形貌调节无机添加剂的添加量来进行调控。

[0037]In step (2), the molecular sieve morphology adjustment inorganic additive is hydrogen peroxide solution. And, the addition amount of hydrogen peroxide solution is 0.15%~5% of the mass of silica-alumina gel, as a more preferred scheme, hydrogen peroxide solution 2 o 2 The amount added is 0.3% to 1.5% of the mass of the silica-alumina gel. In addition, H in hydrogen peroxide solution 2 o 2 The content is 2% ~ 40%, preferably, hydrogen peroxide solution H 2 o 2 The content is 30%. It is worth mentioning that H 2 o 2 It is an environmentally friendly inorganic reagent. It can not only be added to the synthesis gel of molecular sieves to regulate molecular sieve crystals, but also can be ...

Embodiment 1

[0049] Take by weighing 113g silica sol (SiO 2 Content is 30%) and 77g pure water are mixed, then add 1.51g sodium hydroxide, after stirring evenly, then add 3.1g sodium aluminate (Al 2 o 3 content is 75%), continue to stir until a uniform silica-alumina gel is formed, and the molar ratio of each component in the silica-alumina gel is SiO 2 :Al 2 o 3 : Na 2 O: H 2 O=30:1:2:460. After that, add SiO 2 :Al 2 o 3 =25 MFI type molecular sieve seed crystal 1.7g stirred evenly, finally added 2.6g hydrogen peroxide solution (H 2 o 2 content is 30%), after stirring evenly, the mixture was transferred to a stainless steel sealed reaction kettle with polytetrafluoroethylene lining, placed in an oven at 170°C, and crystallized for 48 hours. The crystallized product was cooled, separated (including filtering and washing) and then dried at 120°C for 8 hours to obtain ZSM-5 molecular sieve.

[0050] figure 2 It is the XRD spectrogram of the ZSM-5 molecular sieve sample obtained...

Embodiment 2

[0053] Take by weighing 184g silica sol (SiO 2 content is 30%) and 101g water are mixed, then add 10.3g sodium hydroxide, after stirring evenly, then add 2.5g pseudo-boehmite (Al 2 o 3 Content is 75%) and 1.2g zinc nitrate, continue to stir until forming uniform silica-alumina gel, the molar ratio of each composition in this silica-alumina gel is SiO 2 :Al 2 o 3 : Na 2 O: H 2 O=50:1:7:700. After that, add SiO 2 :Al 2 o 3 =400 MFI type molecular sieve seed crystal 4.5g stir evenly, finally add 1.5g hydrogen peroxide solution (H 2 o 2 content 30%), after stirring evenly, the mixture was transferred to a stainless steel sealed reaction kettle with polytetrafluoroethylene lining, placed in an oven at 155° C., and crystallized for 60 hours. The crystallized product was cooled, separated (including filtering and washing), and then dried at 120°C for 8 hours to obtain Zn-ZSM-5 molecular sieve.

[0054] Figure 4 It is the scanning electron microscope picture of the ZSM-5...

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Abstract

The invention provides an inorganic synthesis method for regulating the morphology of a ZSM-5 molecular sieve. The method at least comprises the following steps: (1) adding a silicon source, an alkali source and an aluminum source into pure water respectively, and stirring uniformly to obtain silica-alumina gel; (2) adding a molecular sieve morphology regulation inorganic additive and a zeolite seed crystal into the silica-alumina gel, and stirring uniformly to obtain a gel mixture; and (3) transferring the gel mixture into a sealed reaction kettle for crystallization, and then separating and drying the crystallized product to obtain a ZSM-5 molecular sieve, wherein the morphology of the ZSM-5 molecular sieve is suitable to be controlled by regulating the addition amount of the molecular sieve morphology regulation inorganic additive. Through the method provided by the invention, a low-silicon ZSM-5 molecular sieve with a regulatable morphology and a silica-alumina ratio controllable in a certain range can be obtained, and the low-silicon ZSM-5 molecular sieve has relatively high crystallinity and purity and good aromatization reaction performance; and moreover, a roasting step is saved in the production process, and environmental pollution is reduced.

Description

technical field [0001] 本发明属于无机化学领域,涉及分子筛制备技术领域,特别是涉及一种调控ZSM-5分子筛形貌的无机合成方法。 Background technique [0002] 具有MFI结构的ZSM-5分子筛及其杂原子取代分子筛因具有较强的酸性而被广泛应用于芳构化等反应中。目前,芳构化催化剂的开发主要集中在具有低SiO 2 / Al 2 o 3 比的、强酸性的、小晶粒ZSM-5分子筛合成及其改性上,其中,ZSM-5分子筛旳形貌调控对催化剂活性和选择性也有重要影响。例如,ZSM-5分子筛晶体中平行于b轴的直孔道较有利于分子在其内的传输与扩散,而平行于a轴的zigzag型孔道相对较利于实现分子的择形性,因此调控分子筛的轴向有利于调整催化剂活性和选择性。近年来报道了多种MFI结构分子筛的形貌调控,如Hwang和Chen等在微波条件下合成了纤维状TS-1和S-1分子筛(Angew.Chem.Int.Ed,2005,44,556;Catal.Today,2006,111,366;Microporous Mesoporous Mater.,2007,104,296;Microporous Mesoporous Mater.,2009,119,217);Davis等人通过利用季铵盐的不同聚合体合成出了轴向长度各不相同的MFI分子筛膜(Chem.Mater.,2004,16,5697;Angew.Chem.Int.Ed,2006,118,1172;Science,2003,300,456);Xiao等人研宄发现往MFI合成凝胶中添加尿素、淀粉、聚合物、四氟化碳等添加剂也能控制a或b轴向的生长(Chem.Commun.,2011,47,1048;ChemCatChem,2013,5,1517);Ryoo等人利用特定的表面活性剂合成了薄片状分子筛(Nature,2009,461,246)。然而,通过上述方法中通常需要加入有机模板剂作为导向剂或添加有机物来调控形貌,不仅会增加成本,而且在高温培烧去除有机化合物时会造成环境污染,特别是会引起纳米ZSM-5分子筛的不可逆团聚。此外,上述报道的方法主要集中在合成较高SiO 2 / Al 2 o 3 比的MFI型分子筛,甚至是S-1或TS-1中,但在无有机模板剂的条件下、通过添加无机试剂...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B39/38
CPCC01B39/38C01P2002/72C01P2004/03C01P2004/20C01P2004/32
Inventor 杨承广吴晛刘子玉丘明煌陈新庆曾高峰孙予罕
Owner SHANGHAI ADVANCED RES INST CHINESE ACADEMY OF SCI
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