Highly efficient green mesostructured urea functionalized on SBA-15 catalysts for selective synthesis of benzlidenemalononitrile

A series of urea-immobilized SBA-15 catalysts were synthesized via post grafting method using 3chloropropyltriethoxysilane (GritS) as the anchoring agent. The solid catalyst was characterized by PXRD, N-2 adsorption-desorption, FT-IR, elemental analyzer, TEM, CO2-TPD and Si-29 CP/MAS NMR. Detailed analysis of the pore size illustrated the mesoporous nature of the immobilized catalyst. The as prepared catalyst was further evaluated in the Knoevenagel condensation reaction under different reaction conditions. Benzaldehyde was employed in the Knoevenagel condensation reaction with malononitrile. Catalytic results showed that the Urea(4.8)/SBA-15 exhibits high efficacy (98% of yield) for promoting this reaction at 40 degrees C and in the absence of a solvent. Under the same reaction conditions, acetylacetone led to a lower benzaldehyde conversion of 10%, whereas ethyl cyanoacetate provides up to 88% conversion. The catalyst could be recycled and reused for at least five reaction cycles with slight loss of catalytic activity. (C) 2017 Elsevier Inc. All rights reserved.