Strongly Acidic and High-Temperature Hydrothermally Stable Mesoporous Aluminosilicates with Ordered Hexagonal Structure

Zhang, Zongtao; Han, Yu; Zhu, Lei; Wang, Qianqian; Yu, Yi; Qiu, Shilun; Zhao, Dongyuan; Xiao, Feng

doi:10.1002/1521-3773(20010401)40:7<1258::aid-anie1258>3.0.co;2-c

Cited by 386 publications

(105 citation statements)

References 27 publications

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“…ZIF-8 thus was further probed and shown to be unchanged for up to 24 h in 0.1 and 8 M aqueous sodium hydroxide at 100°C. We note that the hydrothermal stability of ZIF-8 is superior to those of original MCM and SBA types of ordered mesoporous silica (17), even rivaling the ultrastable derivatives of these materials (20).…”

Section: Resultsmentioning

confidence: 99%

Exceptional chemical and thermal stability of zeolitic imidazolate frameworks

Park

Côté

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

6,435

314

5,102

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Twelve zeolitic imidazolate frameworks (ZIFs; termed ZIF-1 to -12) have been synthesized as crystals by copolymerization of either Zn(II) (ZIF-1 to -4, -6 to -8, and -10 to -11) or Co(II) (ZIF-9 and -12) with imidazolate-type links. The ZIF crystal structures are based on the nets of seven distinct aluminosilicate zeolites: tetrahedral Si(Al) and the bridging O are replaced with transition metal ion and imidazolate link, respectively. In addition, one example of mixed-coordination imidazolate of Zn(II) and In(III) (ZIF-5) based on the garnet net is reported. Study of the gas adsorption and thermal and chemical stability of two prototypical members, ZIF-8 and -11, demonstrated their permanent porosity (Langmuir surface area ‫؍‬ 1,810 m 2 ͞g), high thermal stability (up to 550°C), and remarkable chemical resistance to boiling alkaline water and organic solvents.catalysis ͉ hydrogen storage ͉ metal-organic frameworks ͉ porosity ͉ zeolites A large segment of the global economy ($350 billion) is based on the use of crystalline microporous zeolites in petrochemical cracking, ion-exchange for water softening and purification, and in the separation of gases (1). Zeolite structures are composed of tetrahedral Si(Al)O 4 units covalently joined by bridging O atoms to produce Ͼ150 different types of framework (2). A long-standing challenge is to incorporate transition metal ions and organic units within their pores and, more desirably, to do so as an integral part of the zeolite framework. This ability would be useful in many catalytic applications because the pores would be lined with a high concentration of ordered transition metal sites whose electronic and steric properties can be tailored by functionalization of the organic links. However, the vision of achieving such a zeolite that combines these features remains largely unrealized. Here, we outline a general synthesis of structures having zeolite framework topologies in which all tetrahedral atoms are transition metals, and all bridging ones are imidazolate (IM) units.Imidazole can lose a proton to form IM, 1. In examining the dense-phases Co(IM) 2 and Zn(IM) 2 , whose structures are based on nets of linked CoN 4 or ZnN 4 tetrahedra (3, 4), we noticed that IM bridges make an M-IM-M angle, 1, close to 145°, which is coincident with the Si-O-Si angle, 2, which is preferred and commonly found in many zeolites (see Scheme 1). We believed that it should be possible under the right conditions to prepare metal IMs adopting open-framework zeolite structures. Indeed, a number of relatively new Fe(II) (5), Co(II) (6, 7), Cu(II) (8), and Zn(II) (9) IM compounds have structures that are based on zeolite-like tetrahedral nets. However, these materials are relatively dense (nonporous) and͞or low-symmetry structures. Only very recently, Zn(II) IMs having symmetrical porous structures analogous to zeolites were reported (10). Two of the aforementioned compounds are included, as zeolitic IM framework (ZIF)-7 and -8, among the library of ZIFs we report here (Fig. 1).** The focus of th...

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Section: Resultsmentioning

confidence: 99%

Exceptional chemical and thermal stability of zeolitic imidazolate frameworks

Park

Côté

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

6,435

314

5,102

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“…Because thermal treatment (>373 K) may destroy the pore system of MCM-41 by either dealumination or coking, [40][41][42] the stability of the Pt/MCM-41…”

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confidence: 99%

One-step production of long-chain hydrocarbons from waste-biomass-derived chemicals using bi-functional heterogeneous catalysts

Wen

Barrow

Hattrick‐Simpers

et al. 2014

Phys. Chem. Chem. Phys.

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In this study, we demonstrate the production of long-chain hydrocarbons (C 8+ ) from 2-methylfuran (2MF) and butanal in a single step reactive process by utilizing a bi-functional catalyst with both acid and metallic sites. Our approach utilizes a solid acid for the hydroalkylation function and as a support as well as a transition metal as hydrodeoxygenation catalyst. A series of solid acids was screened, among which MCM-41 demonstrated the best combination of activity and stability. Platinum nanoparticles were then incorporated into the MCM-41. The Pt/MCM-41 catalyst showed 96% yield for C 8+ hydrocarbons and the catalytic performance was stable over four reaction cycles of 20 hour each. The reaction pathways for the production of long-chain hydrocarbons is probed with a combination of infrared spectroscopy and steady-state reaction experiments. It is proposed that 2MF and butanal go through hydroalkylation first on the acid site followed by hydrodeoxygenation to produce the hydrocarbon fuels.

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“…Figure 7 shows FT-IR spectra of intermediate samples such as M, MHT, and MHT8.5HT. It is reported that IR bands in the 420-500 cm -1 region and those between 520 and 600 cm -1 are assigned to internal tetrahedron vibrations such as 6-and 5-rings of T-O-T (T = Si or Al) in zeolites [28]. These IR bands for clinoptilolite and zeolite-P were observed between 430 and 604 cm -1 [29,30].…”

Section: Structural Parametersmentioning

confidence: 99%

“…Several research groups have attempted to use tiny zeolite precursors or secondary building units of synthetic zeolites as starting materials for the preparation of mesoporous materials [3][4][5][6][7][8][9]. Mesoporous materials with moderate acidic properties originated from zeolite precursors have been synthesized from nanoclusters of zeolite Y, zeolite Beta and ZSM-5 [3][4][5][6]9]. Synthesis of hydrothermally stable mesoporous molecular sieves from zeolite mordenite and zeolite L were also reported [7,8].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of MCM-41 with Zeolite-P from Natural Clinoptilolite for Silica-alumina Source Under Hydrothermal Conditions in Alkaline Media

Shindo

Nagai

Ikeuchi

et al. 2011

Int.J.Soc.Mater.Eng.Resour.

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Mesoporous molecular sieve MCM-41 and zeolite-P were synthesized from natural clinoptilolite zeolite and cetyltrimethylammonium bromide under hydrothermal conditions in alkaline media. The formation path of MCM-41 and zeolite-P from natural clinoptilolite was investigated using XRD, TG, SEM, and FT-IR for the samples obtained in the course of the synthesis. XRD and TG results exhibited that in the first stage where the mixture of clinoptilolite and cetyltrimethylammonium bromide was treated in alkaline media at ambient temperature, crystal structure of clinoptilolite did not change significantly. In the second stage where the mixture was subsequently treated under hydrothermal conditions, dissolution of clinoptilolite and formation of zeolite-P were observed, while mesophase with 2d hexagonal structure of MCM-41 was not detected. In the third stage, mesostructure with 2d hexagonal symmetry was gradually formed by the adjustment of pH of the reaction mixture between 10.5 and 8.5. Structural integrity of 2d hexagonal assembly of as-synthesized MCM-41 was improved by controlling pH of the reaction mixture to 8.5 followed by the hydrothermal treatment. In contrast, the structure of zeolite-P was not affected by these treatments. SEM images of the samples showed that small particles of MCM-41 were mainly formed on the surface of the zeolite-P particles and agglomerated to larger grains. Judging from the results of XRD patterns and FT-IR spectra of the samples, it is indicated that smaller crystallites or building units of clinoptilolite that were X-ray amorphous and IR detectable were probably incorporated in the pore walls of MCM-41.

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Strongly Acidic and High-Temperature Hydrothermally Stable Mesoporous Aluminosilicates with Ordered Hexagonal Structure

Cited by 386 publications

References 27 publications

Exceptional chemical and thermal stability of zeolitic imidazolate frameworks

Exceptional chemical and thermal stability of zeolitic imidazolate frameworks

One-step production of long-chain hydrocarbons from waste-biomass-derived chemicals using bi-functional heterogeneous catalysts

Synthesis of MCM-41 with Zeolite-P from Natural Clinoptilolite for Silica-alumina Source Under Hydrothermal Conditions in Alkaline Media

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