Development of Amine Functionalized Wrinkled Silica Nanospheres and Their Application as Efficient and Recyclable Solid Base Catalyst

Amine functionalized wrinkled silica nanospheres (WSiO2-NH2) were successfully synthesized by using a simple biphase sol-gel approach. The prepared silica nanospheres were characterized by using various techniques, such as TEM, FE-SEM, EDX, TGA, X-ray diffraction and FT-IR spectroscopy. The prepared amine functionalized wrinkled silica nanospheres have been, for the first time, explored as an efficient and recyclable solid base catalyst for Knoevenagel condensation. The catalytic efficiency of the synthesized nanospheres was analysed using different aromatic aldehydes and active methylene compounds as reactants under very mild reaction conditions. The exceptional catalytic activity of the WSiO2-NH2 nanospheres is because of the easy accessibility of amine sites to the reactant molecules. This is because WSiO2-NH2 nanospheres have wrinkled structure which provides high surface area and larger pore size. This facilitates the penetration and proper interaction of the reactants molecules with the basic amine groups on the WSiO2-NH2 nanospheres.