Single-step fabrication of Na-TUD-1 novel heterogeneous base nano-catalyst for Knoevenagel condensation reaction

Abstract

This research, for the first time, reports the design and development of a heterogeneous nano-catalyst based on sodium ions (Na+) incorporation in Technical University of Delft (TUD-1) mesoporous silica for Knoevenagel condensation reaction. Facile one-step fabrication of Na-TUD-1 nano-catalysts (varying Si/Na ratio as 100–5) was demonstrated using the sol–gel route. The catalytic performance of Na-TUD-1 was evaluated as a base heterogeneous catalyst in Knoevenagel condensation reaction, which took place under conventional and microwave irradiations conditions using ethanol as a solvent. Na-TUD-1 exhibited superior catalytic activity in comparison to available homogeneous base catalysts such as sodium ethoxide. The Na-TUD-1 nano-catalyst demonstrated identical performance till the fourth run along with high stability and negligible leaching of Na. Moreover, the use of microwave heating reduced the reaction time from 240 to 20 min only with a TOF of 0.58 min−1. Such excellent performance of Na-TUD-1 heterogeneous nano-catalysts will certainly increase its industrial acceptability to achieve affordable and efficient waste-effluent treatments.