The Synthesis Of Zeolites With Hexamethonium As Template

ITQ-13 zeolite belonging to the family of ITH is a novel microporous material and possesses three sets of intercrossed channels which is similar to ZSM-5 but narrower.Due to the unique three-dimensional connectivity of 9 X 10×1 OMR apertures,ITQ-13 had been applied in catalytic cracking of hydrocarbons for boosting propylene,and showed higher propylene yield and selectivity than conventional ZSM-5 zeolite.It is reported that the study of ITQ-13 was just started in the laboratories.It has not been applied in industry by the reasons that the long crystallization time,the high cost and the less reproducibility.So it is very significant and has broad industial applications to study the synthesis to reduce the crystallization time and the cost.The dissertation was focused on changing the system of the initial gel and two approaches of synthesizing the ITQ-13 in a short time were developed.One approach was first developed to synthesize Al-ITQ-13 zeolite in a short time via adding promoter in the initial gels.The samples obtained were characterized by XRD,SEM,N₂ adsorption and FTIR methods.The kinetic parameters were obtained and the crystallization mechanism was discussed by the way of studying the changes of relative crystallinity.It is showed that the framework of ITQ-13 samples synthesized by Rapid synthesis method contained more A1 and the physical properties were similar.The promoter in the gel polarized the hydrophobic hydration spheres formed around silicate units,facilitated the overlapping of SiOSi,thereby reduced the ITQ-13 zeolite nucleation activation energy and growth activation energy,so that the rate of crystallization was improved and the time of crystallization was shortened to llh.The other approach was developed to synthesize A1-ITQ-13 zeolite in a short time via adding Na⁺ and Br^- in the initial gels.Namely,sodium hydroxide was used as the alkali source,hexamethonium bromide was used as the template.At the same time,the crystallization was greatly shortened.The samples obtained were characterized by XRD,SEM,N₂ adsorption,FTIR and Al²7 NMR methods.And the factors in the synthesis were optimized.It is resulted that the ITQ-13 zeolite synthesised in the system containing Na possesses more Al in the framework.It is reported that the different framework can be synthesized by the same template.ITQ-13 zeolite can be synthesized by using the hexamethonium bromide at the same time with EU-1 and the phase were overlapped in same areas.So it is necessary to study EU-1 with ITQ-13.EU-1 zeolite with framework type EUO,which consists of 10-membered ring（10-MR）channels with deep side-pockets circumscribed by 12-MRs which make it the preferred catalytic material for the xylene isomerization.Compared with micro-size EU-1 zeolite,hierarchical zeolite possesses high exterior surface area and shorter pore pathway,so there are lots of apertures and acid sites exposed at the outside surface of the crystal.Hierarchical EU-1 zeolite was synthesized by adding organosilanes in the system.It is charactered that adding organosilanes in the initial gel could decrease the size of the paticle and the hierarchical EU-1 zeolites were obtained.