Shuanghe Meng

Synthesis of mesoporous ZSM-5 using a new gemini surfactant as a mesoporous directing agent: A crystallization transformation process

A new gemini surfactant, [C18H37(CH3)2–N+–(CH2)3–N+–(CH3)2C18H37]Cl2 (C18-3-18), has been successfully used as the mesopore directing agent in the hydrothermal synthesis of mesoporous ZSM-5 (MZSM-5). The synthesis of MZSM-5 was realized with a low temperature crystallization process at 130 °C. The amount of C18-3-18 used in the synthesis affected the relative crystallinity and the textural properties of the obtained MZSM-5. Detailed investigation showed that the formation of MZSM-5 followed a crystallization transformation process. The use of C18-3-18 resulted in the formation of mesoporous material during the early stage of the synthesis, which was converted into MZSM-5 crystals templated by tetrapropylammonium bromide to form the MFI phase. As the synthesis proceeded, the MZSM-5 crystals aggregated into particles by weak interactions. This work shows that C18-3-18 can be used as a mesopore directing agent, which could provide a route for the synthesis of other mesoporous zeolites.

Creating mesopores in ZSM-5 for improving catalytic cracking of hydrocarbons

Alkaline treatment method was employed in preparing high efficient catalytic cracking catalyst. The crystalline structure, morphology and new porosity formation was evidenced by XRD, SEM and N 2 adsorption. The n-hexane catalytic cracking were carried out over the two sample prepared with and without alkaline treatment. The enhanced conversion was attributed to the coexistence of mesoporous and microporous surface.