The Synthesis And Characterization Of Heteroatom-Substituted Aluminophosphates Molecular Sieves

The special performances of zeolites have an intimate association with itsporous framework （such as composition, channel size, dimension, direction, and thenature of the channel surface, etc.）. Recently, the rapid development of zeoliticmaterials in the areas such as catalysis, petrochemical and fine chemical industry,emphasizes the strategic status of synthesis and preparation chemistry of zeoliticmaterials. Therefore, scientific researchers have arised broad attention on thestructure design, synthesis, characterization and exploration of novel synthetic route,etc. Aluminophosphate molecular sieves have been extensively studied due to theirrich structural architectures and thermal stability. Particularly, heteroatom-substitutedaluminophosphate molecular sieves not only develop new compositions and novelstructures, but also have exhibited special redox and catalytic properties because ofthe creation of acid sites and redox centers, as well as photoluminescence properties,electronic conductivity and magnetic properties.Herein, we mainly focus on the preparation and characteristics of theheteroatom-substituted aluminophosphate molecular sieves.Main achievements are as follow:1. Two new zinc-substituted aluminophosphate molecular sieves ZnAPO-CJW1(|(C₅H₁₄N₂)₄|[Zn₈Al₈P₁₆O₆₄]·4H₂O) and ZnAPO-CJW2(|(C₆H₁₆N₂)₄|[Zn₈Al₈P₁₆O₆₄])with CGS-zeotype structures have been synthesized under hydrothermal conditions byusing1-methylpiperazine and1,2-diaminocyclohexane （DACH） as thestructure-directing agents, respectively. They are the first examples of zinc-substitutedaluminophosphate molecular sieves with the CGS-zeotype structure. Their structuresare determined by single-crystal X-ray diffraction and further characterized by powder X-ray diffraction （XRD）, Inductively coupled plasma （ICP）,Thermogravimetric （TG） and Solid state NMR. The three-dimensional framework ofZnAlPO-CGS contains interconnecting three-dimensional channels systems of10MR×8MR×8MR channels along [100],[010] and [001] directions. The structure ofZnAlPO-CGS is based on the strict alternation of ZnO₄/AlO₄tetrahedron and PO₄tetrahedron to form an anionic framework, in which50%of the aluminum sites arereplaced by transitional metal ions. This substitution is determined by the host-guestcharge-density matching. Charge neutrality is achieved by extra-frameworkprotonated1-methyl piperazine and1,2-hexamethylene diamine cations, respectively.The asymmetric structure unit contains four crystallography inequivalence of zincmetal （Al） atoms （zinc/Al=1/1）, four inequivalence of phosphorus atoms. Crystaldata: ZnAPO-CJW1,(|(C₅H₁₄N₂)4|[Zn8Al8P16O64]·4H2O), Monoclinic, P21/c, a=14.2750（10）, b=16.3222（10）, c=8.6687（6）, α=γ=90o, β=90.4700（10） oand Z=4; ZnAPO-CJW2,|(C₆H₁₆N₂)4|[Zn8Al8P16O64], P21/c, a=14.3371（19）, b=16.303（2）, c=8.7865（11）, α=γ=90o, β=90.315（2） o and Z=4. Theheteroatom substituted aluminophosphate molecular sieves are promising materials inoptics and magnetism, as well as in catalysis as important single-site solid catalysts.2. A cobalt-substituted aluminophosphate molecular sieve|(C₅H₁₄N₂)|[Co₂Al₄P₆O₂₄], denoted as CoAPO-CJW3, has been synthesized under hydrothermalconditions by using1-methylpiperazine as the structure-directing agent, which is firstused as template in the synthesis of cobalt-substituted aluminophosphate molecularsieves with the LEV-zeotype structure. The correlation between structure andtemplate is explored after discussing the similarity in building structures of LEV,CHA, CGS topologies and in the templates used in the reactions.3. A zinc-substituted aluminophosphate [C₆H₁₆N₂][Zn₂Al₃P₅O₂₀]（designated asZnAPO-CJ61） has been hydrothermally prepared by using1,2-diaminocyclohexane asthe template, which exhibits a new zeotype structure. Its inorganic structure isconstructed from strict alternation of PO₄and AlO₄（ZnO₄） tetrahedra to form ionicframework [Zn₂Al₃P₅O₂₀]2-. Charge neutrality is achieved by extra-frameworkprotonated1,2-hexamethylene diamine cations. Elemental analysis shows that theZn/Al ratio is4/5. The Structure of ZnAPO-CJ61contains two dimensional8-ring channels along the [100] and [010] directions, respectively. Notably, ZnAPO-CJ61isa new member of ABC-6family and comprised of d6r, can [4665], gme [43466283] anda novel cage [4³4⁶4⁶6²6³8³8⁶].In summary, this thesis is mainly focused on the synthesis and characterizationof heteroatom-substituted aluminophosphate molecular sieves. A series of zeoliticcompounds with various structure architectures and compositions have beensuccessfully synthesized. It gives a wide investigation on the molecular engineeringof zeolitic materials from serial aspects of theoretical chemistry, synthetic chemistry,structural chemistry, and characterization.