Synthesis and characterization of novel aminopropylated fly ash catalyst and its beneficial application in base catalyzed Knoevenagel condensation reaction

A series of solid base catalysts were synthesized by functionalization of different weight fractions (5, 10, and 15 wt.%) of 3-aminopropyltrimethoxysilane (APTMS) on thermally activated F- type fly ash (SiO2 and Al2O3 > 70%). Catalyst characterization was undertaken using different analytical techniques such as FTIR, XRD, SEM-EDX, TEM, N-2(-) adsorption desorption, BET surface area analysis, TGA and MS. The results showed that appropriate amount (10 wt.%) of aminopropyl groups results in excellent catalytic performance tested for condensation of ethyl cyanoacetate and cyclohexanone at 120 degrees C to produce Ethyl (cyclohexylidene) cyanoacetate (92% yield), an important intermediate of gabapentin (Neurontin), widely used in the treatment of epilepsy to relieve neuropathic pain, under solvent free conditions and in low cost route. The catalyst NH(2)FA-10 was reusable up to three reaction cycles. The work reports an innovative use of solid waste fly ash as an effective solid base catalyst. (C) 2011 Elsevier B.V. All rights reserved.