MIL-96, a Porous Aluminum Trimesate 3D Structure Constructed from a Hexagonal Network of 18-Membered Rings and μ 3 -Oxo-Centered Trinuclear Units

ArticleinJournal of the American Chemical Society 128(31):10223-30 · September 2006with50 Reads
DOI: 10.1021/ja0621086 · Source: PubMed
Abstract
A new aluminum trimesate Al12O(OH)18(H2O)3(Al2(OH)4)[btc]6.24H2O, denominated MIL-96, was synthesized under mild hydrothermal conditions (210 degrees C, 24 h) in the presence of 1,3,5-benzenetricarboxylic acid (trimesic acid or H3btc) in water. Hexagonal crystals, allowing a single-crystal XRD analysis, are grown from a mixture of trimethyl 1,3,5-benzenetricarboxylate (Me3btc), HF, and TEOS. The MIL-96 structure exhibits a three-dimensional (3D) framework containing isolated trinuclear mu3-oxo-bridged aluminum clusters and infinite chains of AlO4(OH)2 and AlO2(OH)4 octahedra forming a honeycomb lattice based on 18-membered rings. The two types of aluminum groups are connected to each other through the trimesate species, which induce corrugated chains of aluminum octahedra, linked via mu2-hydroxo bonds with the specific -cis-cis-trans- sequence. The 3D framework of MIL-96 reveals three types of cages. Two of them, centered at the special positions 0 0 0 and 2/3 1/3 1/4, have estimated pore volumes of 417 and 635 A3, respectively, and encapsulate free water molecules. The third one has a smaller pore volume and contains disordered aluminum octahedral species (Al(OH)6). The solid-state NMR characterization is consistent with crystal structure and elemental and thermal analyses. The four aluminum crystallographic sites are resolved by means of 27Al 3QMAS technique. This product is able to sorb both carbon dioxide and methane at room temperature (4.4 mmol.g(-1) for CO2 and 1.95 mmol.g(-1) for CH4 at 10 bar) and hydrogen at 77 K (1.91 wt % under 3 bar).
    • "This is agreement with the higher development of porosity obtained at higher pyrolysis temperature. Table 2shows the comparative study of our results to other works concerning the adsorption of CO 2 and CH 4 at similar pressure and temperature using activated carbon based on lignocellulosic material (ACP410) [6,53], MOFs (MOF-76 Tm(III) [54], Mil-102 [55], CAU-10 [49] and Mil-96 (Al) [56]) and zeolite [57] . The maximal adsorption capacity of CO 2 obtained in PF- 1000 is low compared to activated carbon ACP410. "
    [Show abstract] [Hide abstract] ABSTRACT: Nanoporous carbons were synthesized at certain conditions by sol–gel method combined with furnace firing in inert atmosphere from pyrogallol-formaldehyde (PF) mixtures in water using perchloric acid as catalyst. Their morphology was studied experimentally to examine their adsorption capacity for greenhouse gases. The preparation conditions of the nanoporous carbons were explored by changing the pyrolysis temperature. The effect of this factor on determining the pore structures and the adsorption capacities were evaluated. The synthesized xerogels were characterized by X-ray diffraction, nitrogen adsorption–desorption isotherms, thermogravimetric analysis (TGA), differential thermal analysis (DTA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that surface areas and nitrogen adsorption capacity are dependent completely on the pyrolysis temperature. Equilibrium and enthalpies studies for the CO2 and CH4 adsorption on PF were measured at room temperature and up to 25 bar. The adsorption capacity on PF was highest for CO2 and then CH4. The best sample shows maximal adsorption capacities as follows 5.50 mmol g−1 of CH4 and 7.62 mmol g−1 of CO2 at 25 bar and 30 °C.
    Full-text · Article · Jun 2016
    • "The corresponding adsorption capacities are summarized inTable 1. Similarly to the present study, the maximal adsorption capacity of CO 2 and CH 4 obtained in for 2 is low compared to materials Zn-FMA [84] and HKUST-1 [85]. On the other hand, sample 2 shows higher capacities than MIL-96(Al) [86], MIL-102 [87] or zeolite 13X [88] (seeTable 1). "
    [Show abstract] [Hide abstract] ABSTRACT: Two novel three-dimensional microporous coordination polymers with composition {[Ln(μ6-BTC)(H2O)]·DMF}n (Ln = Ho(III) (1) and Tm(III) (2); BTC-benzene-1,3,5-tricarboxylate) have been solvothermally synthesized and their preparation conditions were optimized. Single crystal X-ray diffraction experiments showed, that both compounds display similar structures with (6, 6)-connected nets and 1D sinusoidally shaped channels with sizes about 6.7 × 6.7 Å2. Activation process and stability of the frameworks were studied by infrared spectroscopy measured at different temperatures, thermogravimetry coupled with evolved gas analysis and by high energy powder X-ray diffraction experiments measured during in-situ heating. The compounds exhibited high thermal stability, up to 600 °C. Nitrogen and carbon dioxide measurements at low pressures showed BET surface area of 600 m2 g−1 for the sample 1 and 590 m2 g−1 for the sample 2. The carbon dioxide uptake at 0 °C and 1 atm was ∼12 wt.% for both compounds. The adsorption behaviour of 2 has been also investigated by high pressure adsorption measurements of pure methane, carbon dioxide, and nitrogen at 30 °C and pressures up to 26 bar. The measured maximal adsorption capacities were 5.03 wt.% of CH4 at 20 bar, 6.10 wt.% of N2 and 21.95 wt.% of CO2 at 26 bar and 30 °C.
    Full-text · Article · Oct 2015
    • "The huge increase in the surface area is achieved by changing organic linker [36]. Similarly, different metal ions/clusters are found to form similar topological frameworks with different physicochemical properties (such as CUSs or OMSs, stability, and Lewis acidities) when they react with the same organic linker [34], e.g., CPO-27 (Me-DHTP (2,5-dihydroxyterephthalate); Me: Co 2+ , Ni 2+ , Fe 2+ , Mn 2+ , Zn 2+ ) [37][38][39], MIL-100 (Me-BTC (benzenetricarboxylate); Me: Fe 3+ Cr 3+ , Al 3+ ) [40][41][42], MIL-96 (Me-BTC; Al 3+ , Cr 3+ , Ga 3+ , In 3+ ) [43][44][45][46]. Another fascinating feature of MOFs is the ability to tune their physicochemical properties after the crystalline materials have already been formed [47][48][49][50]. "
    [Show abstract] [Hide abstract] ABSTRACT: Provision of clean water is one of the most important issues worldwide because of continuing economic development and the steady increase in the global population. However, clean water resources are decreasing everyday, because of contamination with various pollutants including organic chemicals. Pharmaceutical and personal care products, herbicides/pesticides, dyes, phenolics, and aromatics (from sources such as spilled oil) are typical organics that should be removed from water. Because of their huge porosities, designable pore structures, and facile modification, metal-organic frameworks (MOFs) are used in various adsorption, separation, storage, and delivery applications. In this review, the adsorptive purifications of contaminated water with MOFs are discussed, in order to understand possible applications of MOFs in clean water provision. More importantly, plausible adsorption or interaction mechanisms and selective adsorptions are summarized. The mechanisms of interactions such as electrostatic interaction, acid-base interaction, hydrogen bonding, π-π stacking/interaction, and hydrophobic interaction are discussed for the selective adsorption of organics over MOFs. The adsorption mechanisms will be very helpful not only for understanding adsorptions but also for applications of adsorptions in selective removal, storage, delivery and so on.
    Article · Sep 2014
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