The Optimized Synthesis And Characterization Of ZSM-35 Zeolite In Extremely Dense Nonamine System

ZSM-35 with a lamellar FER topology are promising new catalytic materials, which comprise two different kinds of perpendicularly intersected pore systems of 10 member rings and 8 member rings. Up to now, research on the ZSM-35 zeolite has focused on crystallization behavior and influence factors from liquid phase transformation mechanism as well as new methods to synthesize ZSM-35 from solid phase transformation mechanism. In addition, ZSM-35 zeolite show high thermal/hydrothermal stability, strong acidity, and excellent catalytic performance in several reactions. So ZSM-35 zeolite had been synthesized by different methods and using different templates. The templates usually have following characteristics:1. Because of the toxicity and corrosiveness, they are harm to the health of workers and operators.2. The emission of waste liquid cause pollution to the environment. 3. The high price of templates accouts for 50% of total production costs, which keeps the production costs at a high level.4. The template must be easy pyrolysis, therefore the zeolite would be easy activated to become catalyst carrier.Because of all above reasons, the synthesis of ZSM-35 zeolite without using templates has a very high economy value. So a new green synthesis route must be searched, to reduce the pollution to the environment and the synthesis cost.In this dissertation, ZSM-35 zeolite was first synthesized in the extremely dense nonamine system. The influences of SiO₂/Al₂O₃ ratio, OH^-/SiO₂ ratio, the dosage of water, crystallization temperature and crystallization time on the crystallization of ZSM-35 have been clarified elaborately. By tracing the whole crystallization process, it was found that the silicon and aluminum elements does not exist in the liquid. This suggests that the crystallization occurs just through solid phase transiformation mechanism. By analyzing crystallization procedure and structural characters of the co-crystalline zeolites, it can be speculated that the stability change of the channel systems causes the the crystal transformations among several zeolites(FER, MOR, MFI) owing to the same 5-ring subunits they all share.By the test of the XRD,SEM and FT-IR, the sample was determined to be the pure ZSM-35 zeolite. But when a test of nitrogen adsorption had been conducted, it was found that the BET surface area, micropore area and volume were smaller than the parameter of the synthesis sample by in situ solid-transformation method. And the MOR zeolite was synthesized very easily in the synthesis process of ZSM-35 zeolite. So a series of experiments to optimize the synthesis condition of ZSM-35 zeolite in the extremely dense nonamine system was conducted. As a result, the addition of absolute ethanol to the reaction system could increase the crystallinity of ZSM-35 zeolite significantly, and it could inhibit the growth of the MOR impurity. Then the influences of absolute ethanol dosage on the crystallization of ZSM-35 and the morphology of the crystal was emphatically investigated. And the effect of absolute ethanol addition on the range of the SiO₂/Al₂O₃ ratio was also investigated. By the test of the nitrogen adsorption and catalysis performance of the sample, it was found that the sample's pore parameters of optimized synthesis were improved evidencely.