Hydrothermal Synthesis And Characterization Of Germanosilicate Zeolites

Zeolites are of a sort of important inorganic material, which are with regular porestructure and large inner surface. They were widely used in catalysis, adsorption,separation and ion exchange. The aim to develop novel zeolites is important researchfield, which solves the problem in the applications. In recent years, newgermanosilicate zeolites were developed. The synthesis of extra-large porous andhierarchical-meso-micro porous zeolites attracted much interest.In this dissertation, the silicates were selected as the main research system, andthe germanium was added in it. The products in the mixture system were stable as thesilicates and of much new structure. We designed a series of new organic compoundas the structure-directiong agent. In the hydrothermal condition, the amount of waterwas retrained strictly to be fit for the large and extra-large pore zeolites. The F-wasalso added into the reaction system to obtain the double four rings and double threerings structure. These structures could low the framework density. The Aluminiumwas added into the system to increase the number of the acid sites in the framework ofthe germanosilicate zeolites. The chiral mesoporous germanosilicate ITQ-37with30-rings and the extra-large germanosilicate ITQ-44with18-rings were synthesizedby our new organic structure-directing agent. The synthesis and charaction of themwere carefully studied.The chiral mesoporous zeolite germanosilicate ITQ-37has been prepared byusing a new achiral organic structure-directing agent3’,4’-dihydro-1’H-spiro[isoindoline-2,2’-isoquinolin]-2-ium. The crystallization fielddiagram and the influence of synthetic factors on the synthesis of ITQ-37, such ascrystallization temperature, crystallization time, source materials, and water amounthave been studied. The as-synthesized samples have been characterized by XRD, ICP,CHN, TG-DTA, TEM, DLS, NMR, N2adsorption and NH₃-TPD. The results indicatethat the as-synthesized ITQ-37is a pure phase, and the particle size is of ca.200nm.The OSDA cations remain intact in the final product of as-synthesized ITQ-37and theframework structure of ITQ-37maintains up to500oC after the removal of organic templates. In addition, a little amount of Al atoms can be introduced into theframework of germanosilicate ITQ-37forming Al-ITQ-37mainly with the weak acidsites.The18-ring zeolite germanosilicate ITQ-44has been prepared by using twoorganic structure-directing agent （SDA）3’,4’-dihydro-1’H-spiro[isoindoline-2,2’-isoquinolin]-2-ium andbenzyltriethylammonium bromide. The crystallization field diagram and the influenceof synthetic factors on the synthesis of ITQ-44, such as crystallization temperature,crystallization time, the ratio of Si/Ge, the amount of the F-and water amount havebeen studied. The as-synthesized samples have been characterized by XRD, ICP,CHN, TG, SEM, NMR, N₂adsorption and NH3-TPD. The results indicate that theas-synthesized ITQ-44is a pure phase. The SDA-2cations remain intact in the finalproduct and the framework structure of ITQ-44maintains up to500oC after theremoval of SDA. In addition, a little amount of B, Al, Ga atoms can be introducedinto the framework of germanosilicate ITQ-44forming its mainly weak acid sites.The18-ring extra-large pore zeolite ITQ-33has been prepared by usingtetrabutylphosphonium hydroxide as structure-directing agent. In-situ temperaturedependent XRD analysis shows that the framework structure of the as-synthesizedproduct maintains up to500℃. Its adsorption character has been confirmed by theN2adsorption. The influence of synthetic factors in the synthesis of ITQ-33has beenstudied.Also a series of commercial organic compounds were selected to be used in thesynthesis of ITQ-7and ITQ-17with12-ring large pore system structure. The wateramount was extremely controlled, and the experiments were exactly designed. Theonly reason was to explore the connection of the reaction system and the finalproducts. The final aim was to supply the developing of the new zeolites with thethermo and experiment foundation.