Base catalytic properties of organoamino-silica hybrids prepared using cashew nut shell liquid components as templates
Loading...
Date
2011
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Dar es Salaam
Abstract
This work was aimed at finding the catalytic efficiency of organoamino-silica
hybrids prepared over some components of cashew nut shell liquid (CNSL) as
templates. Cardanol and anacardic acid as major components of CNSL, were
screened for their efficiency as templates in synthesizing the hybrids. The hybrids
were prepared by one-pot co-condensation of three classes of organoaminesilanes
and tetraethoxysilane at two different loading ratios, namely 1:4 and 1:9. The results
showed that anacardic acid and cardanol formed about 9.2% and 66.3% yields,
respectively. Consequently most hybrids were therefore prepared using cardanol. A
few hybrids were also prepared using a mixture of cardanol and dodecylamine, the
later being a previously established template. The prepared hybrids were
characterized by using HC1 acid titration technique, Diffuse Reflectance Infrared
Fourier Transform Spectroscopy (DRIFTS) and Atomic Force Microscopy (AFM).
Results indicated that the organic group loading ranged between 0.5 to 2.3 mmol per
gram of silica, depending on the loading ratio, type of template and nature of the
organoaminesilane. On the other hand, DRIFTS results revealed that the
organoaminesilyl groups were successfully incorporated in the silica matrix for each
category of the template used. Furthermore, by using AFM the grain size average for
cardanol templated hybrids were found to be about 0.25 pm wide and those of the
co-templated hybrids were about 0.4 pm wide with irregular shapes. The hybrids
were tested for catalytic activity in a model Henry reaction, in particular a reaction
between benzaldehyde and excess nitroethane. Results showed that 81% to 98% of
benzaldahyde could be converted into product within 3 h showing that the prepared
hybrids are suitable catalysts for the model reaction.
Description
Dissertation
Keywords
Organoamino-silica, Cashew nut shell