Modified Silico-Tungstate: An Easy and Efficient Catalyst for the Acetylation of Amines Under Solvent-Free Condition

In this present work, organo-functionalization of silica gel was carried out using 3-aminopropyltriethoxysilane (APTES) as a reactive surface modifier. Tungstate ion (WO4 (2-)) was immobilized onto the modified silica gel and its catalytic activity was investigated for acetylation of amines under solvent-free conditions. The method is highly chemoselective-amine group was selectively acetylated in presence of the hydroxyl group. The above catalyst gave acetylated products in excellent yield in shorter duration of time. The catalyst was characterized by various techniques such as BET surface area measurements, FTIR, CHNS, C-13-CPMAS-NMR, ED-XRF and diffuse reflectance UV-vis techniques. The catalyst was reused five times without significant loss of catalytic activity.