The Syntheses And Characterizations Of Transition Metal-Substituted Aluminophosphate Molecular Sieves

Due to the application of heterogeneous catalysis, ion exchange, adsorption andseparation, inorganic micropore materials attract the attention closely by the scientists.Since1982, S.T. Wilson et al. firstly synthesized aluminophosphate molecular sieves（AlPO₄-n）–one important member of inorganic micropore materials, which was thebeginning of the research and exploration of aluminophosphate molecular sieves.Through almost30years hard-working, many aluminophosphate molecular sieveswith different topologies framework were synthesized by the introduction of organicamine as the structure directing agent. The frameworks of aluminophosphatemolecular sieves are the neutral frameworks which are built by the strict alternation ofAlO₄tetrahedra and PO₄tetrahedra. The Al and P can be replaced by Si or otherelements and the heteroatom substituted aluminophosphate molecular sieves withricher frameworks and properties are formed. Among the heteroatoms, theintroduction of transition metal elements offers the centers of redox and Br nsted acidfor the materials. These advantages make the materials be the excellent solid singlesite catalyst and attract common attention. Moreover, transition metal-substitutedaluminophosphate molecular sieves have wide application in the field of optics,magnetic, chirality because of the rich physical and chemical properties of transitionmetal elements.This thesis focused on the design and synthesis of transition metal-substitutedaluminophosphate molecular sieve. We synthesized two transition metal-substitutedaluminophosphate molecular sieves with a new zeolite topology in the solvothermalsystem and make the relevant contrast and research according to its structural feature.Main achievements are as follow:1. We synthesized two transition metal-substituted aluminophosphate molecularsieves|(C₄NH₁₂)₄|[M₄Al₁₂P₁₆O₆₄]（denoted MAPO-CJ69，M=Co or Zn） with anew zeolite topology in the solvothermal system. The anionic framework[M₄Al₁₂P₁₆O₆₄]^4-of MAPO-CJ69structure was constructed by the strict alternation of metal-centered （Al/M）O₄tetrahedra and PO₄tetrahedra. Thestructure contains two intersecting8-ring channels along the [010] and [001]directions, and the protonated diethylamine cations reside in the8-ring channels toachieve charge neutrality. Based on the element analysis and bond lengths of M-Oand Al-O, we confirm the ratio of M/Al is1/3in the framework. The intrinsicsymmetry of MAPO-CJ69framework is P2/c with four different T sites. Thevertex symbols for four T sites in the net ofMAPO-CJ69are4.6.4.6.6.8,4.6.4.6₂.4.8,4.8.4.8₂.6₃.8, and4.4.4.8.6.6₃. What’smore, the synthetic system was systematically researched among the influencefactors, such as the structure directing agent, H3PO₄, water, transition metalelements and so on. As a framework which is only be prepared asheteroatom-substituted aluminophosphate molecular sieve, MAPO-CJ69isanother good instance which the heteroatom can stabilize the zeolite frameworkand expand the number of zeolite topology.2. The structure of MAPO-CJ69is built up exclusively by4-4-SBUs, which hasbeen found in some known zeolites such as SFO, AFR and OWE. Such4-4-SBUscan be linked through the “head to tail” as well as “shoulder to shoulder” modes.The “head to tail” connection of the4-4-SBUs forms both the undulating layerand the planar layer. The structures of SFO and AFR can be described by linkageof the undulating layers via the “inversion symmetry” and “mirror symmetry”,respectively, while the structures of MAPO-CJ69and ZON can be viewed asconnection of the planar layers via “inversion symmetry” and “mirror symmetry”,respectively. Furthermore, layers formed by the “shoulder to shoulder” connectionof the4-4SBUs can generate OWE, as well as a hypothetical zeolite H-CJ69via“inversion symmetry” and “mirror symmetry”, respectively. This work not onlydemonstrates a new zeolite topology, but also provides an insight into constructionof zeolite frameworks.