Synthesis And Characterization Of Mesostructured Metal Organophosphonates

Porous metal phosphonates, possessing unique hybrid frameworks owing to tailoring organic groups and various metals, and high specific surface, tunable pore sizes and intrinsic acidic property as well as the coordinating characteristics, make them have potential applications in the fields of catalysis, adsorption and separation, host-guest chemistry, et al. In this thesis, a series of mesostructured metal phosphonats including zirconium, aluminum, tin, titanium and tungsten, were fabricated. These materials were further applied as solid acid catalysts, heterogenous catalyst for CO2chemical fixation, adsorbents for heavy metal adsorption and dye removal, et al. The main contents are as follows:1. A series of mesostructured zirconium organophosphonates were successfully synthesized via hydrothermal route with CTAB as surfactant template and ZrOCl2as zirconium source. With1-hydroxy ethylidene-1,1’-diphosphonic acid (HEDP) as phosphorus, mesoporous zirconium organophosphonates (ZrHEDP-x-24) were obtained with different P/Zr molar ratios, which have high specific surface areas (702-970m2/g), uniform pore sizes (3.4-3.6nm) and large pore volumes (0.74-0.86cm3/g); When HEDP was replaced by amino trimethylene phosphonic acid (ATMP) or sodium salt of ethylene diamine tetra (methylene phosphonic acid)(EDTMPS), another two mesoporous zirconium organophosphonates ZrATMP and ZrEDTMPS were synthesized with much longer organic groups integrated in the hybrid framework; When ethanol, acting as cosurfactant, was added in the synthetic aqueous solution, microporous zirconium phosphonates (E-ZrHEDP-8-y) and ordered mesoporous zirconium phosphonate (E-ZrHEDP-4-24), bridged with1-hydroxyethylidene groups in the hybrid framework were prepared by controlling synthetic parameters. The pore sizes for E-ZrHEDP-8-y. can be tuned from small micropore (0.87nm) to mid-meso (2.50nm) range, in combination of microporous surface area from116to509m2/g and pore volume from0.11to0.35cm3/g.Above prepared hybrid porous zirconium organophosphonates were applied to multiple applicantions including as solid acid catalyst, as catalyst to catalyze CO2chemical fixation and as adsorbent for dye removal. E.g. ZrHEDP-x-24samples were used as solid acid catalysts for preparation of methyl-2,3-O-isopropylidene-β-D-ribofuranoside from D-ribose, and exhibited robust catalytic activity with high product yield and good reusability with desirable stability, due to their high specific surface area and abundant porosity. Besides, mesoporous hybrid zirconium organophosphonates ZrHEDP, ZrATMP and ZrEDTMPS exhibited high catalytic activities per proton acid active site in hydrolysis of acetyl acetate and high TOFs for esterification of acetic acid with ethanol, due to the combination of the larger specific surface area, abundant mesoporosity and hydrophobicity of pore surfaces created by the embedded organic groups in the framework, when compared with NKC-9and ZrPO4. In the esterification of acetic acid with cyclohexanol, all the three hybrid catalysts showed superior recyclability. As a new type of chemical CO2fixation catalysts, those three hybrids were served as efficient heterogeneous solid to catalyze the cyclization of aziridines with green and sustainable CO2as C1building block under mild conditions without co-catalysts and solvents. The whole preparation process was non halogen-contained, economic, safe and environmentally benign, along with the high yields (60-96%) and excellent regio-selectivity (93-98%) for the reactions of various aziridines with CO2.When E-ZrHEDP-x-y was used as adsorbent to removal dyes, E-ZrHEDP-4-24with mesopore size of2.41nm exhibited higher adsorption capacity and more rapid adsorption rate for the organic dyes removal than the identical compositional materials with smaller pore sizes (0.87nm and1.62nm). Besides, RhB-loaded ZrHEDP-4-24composite exhibited a comparable fluorescence to RhB in ethanol. All above suggest the potential of microporous and mesoporous hybrid zirconium organophosphonates in the field of solid acid catalysts, adsorbents and as host to load luminescent dyes to be used as solid-state dye lasers and optical devices.2. Aluminum phosphonates in the form of lamellar mesostructure with crystalline pore wall,2D-hexagonal and particle-aggregated mesophase, as well as their corresponding flower-like, block-like and granule-aggregated particle morphologies, have been synthesized with the use of Al(NO3)3, AICl3and Al2(SO4)3as aluminum source via surfactant-templating solvent-evaporation method. The influences of counteranions both on the mesostructure and the morphology of organic-inorganic hybrid materials have been discussed and the present work extended the effect of inorganic additives from inorganic silica to organic-inorganic hybrid materials.3.2-D hexagonal mesostructured tin phosphonate with HEDP as phosphorus and SnCl4·5H2O as tin source was prepared with the assistance of CTAB as template through hydrothermal route. It was the first time for the successful preparation of periodic mesostructured hybrid tin phosphonates.4. Surfactant-templating strategy was used to synthesize mesoporous titania-silica-phosphonate triconstituent hybrid materials (TSP) in the form of submicrometer-sized particles with disordered wormhole-like mesostructure, in microemulsion system by utilizing CTAB as surfactant, TEOS, TiCl4and EDTMPS as the silica, titania and P sources, respectively. The integration of silica in the TSP framework could be in favor of the improvement of the regularity of mesostructure, as well as the enlargement of the specific surface area, pore volume and pore diameter. TSP materials were used to adsorb CO2in gas phase and heavy metal ion Cd (II) in aqueous solution.5. A new mesostructured hybrid assembly consisting of Keggin-type organophospho-tungstate anions and cetyltrimethylammonium cations (HOPW-CTA) was prepared with HEDP as phosphorus, and Na2WO4as tungsten source. The obtained hybrid had crystallized nanoparticles in size of10-30nm possessing elliptical and round shapes. The organophospho-tungstate anion clusters for this material are Keggin type, which were characterized by FT-IR, UV-vis, Raman and31P MAS NMR. When HOPW-CTA was used to catalyze the oxidation of styrene, a moderate yield of77.7%for phenyl glycol was generated with another useful byproduct a-hydroxyacetophenone (15.5%) in "Green" aqueous solution.