دانلود رایگان مقاله انگلیسی سیلیس سیلیکا مزوزوپور بزرگ به عنوان یک کاتالیزور پایدار کارآمد - اشپرینگر 2017

Abstract

In this study, mesoporous silica materials with tuned pores and surface areas were successfully synthesized by adjusting the amount of applied hexane and controlling the hydrothermal temperature. The synthesized silica materials were then functionalized by an amine group to produce solid base catalysts and be applicable as efficient heterogeneous base catalysts for the Henry reaction. The mesoporous silica catalysts possessing large-pores and surface area expose their active catalytic sites and thereby improve contacts with reactants fulfilling the reactions expeditiously in comparison with solid base catalysts possessing smallpores and surface area. The results indicated that the yield of the products is significantly dependent on the structure of the applied solid base catalysts. The modulated large-pore solid base catalysts presented high catalytic activity in Henry reactions and could be reused for five consecutive cycles.

Conclusions

In conclusion, we prepared mesoporous silica materials with tunable pores and surface areas by controlling the amount of hexane and hydrothermal temperature. The prepared mesoporous silica materials could be easily functionalized by amine group to be utilized as retrievable solid base catalysts for heterogeneous Henry reactions. The modulated framework possesses large-pores with active amine functional groups on its high surface area; thus, this enhances the exposed active catalyst sites and contacts with reactants accelerating the reaction completion efficiently. The designed large-pore solid base catalyst could be reused for five consecutive cycles in nitroaldol condensation of benzaldehyde.