| 초록 |
Biodiesel production usually results in a huge amount of glycerol, raising a critical need to transform it into high added value products. The present study highlights that solvent-free, conventional thermal activation, and non-conventional microwave/ultrasonic activation in the liquid phase are able to selectively transform glycerol into cyclic acetals and ketals using an optimised acid activated clay catalyst. The active sites of the catalyst were examined by volumetric titration and confirmed by pyridine adsorbed FT-IR and advanced NH3-TPD analyses. The activation performed at relatively mild conditions, i.e.; 6N H2SO4 and 6% w/v clay, reproducibly resulted in an improved surface area (180 m2 g−1) and surface acidity (23 mg KOH g−1), with superior quantitative Brönsted and Lewis acidic sites. Moreover, the eco-friendly process involving a catalyst, microwave, or ultra-sonication were successfully utilized to achieve commercially valuable hyacinth fragrance. |
