176856-74-9Relevant academic research and scientific papers
Clay catalysed rapid valorization of glycerol towards cyclic acetals and ketals
Pawar, Radheshyam R.,Gosai, Kalpeshgiri A.,Bhatt, Adarsh S.,Kumaresan,Lee, Seung Mok,Bajaj, Hari C.
, p. 83985 - 83996 (2015)
Biodiesel production usually results in a huge amount of glycerol, raising a critical need to transform it into high 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. Several parameters for the acid activation of bentonite clay were optimized under mild reaction conditions with a high concentration of clay (6%) and varying the acid concentration in the range of 6 to 15 N. The acid-activated clay samples were characterized by XRD, FT-IR, BET, and XRF analysis. 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.; 6 N 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 Br?nsted and Lewis acidic sites. Moreover, the eco-friendly process involving a catalyst, microwave, or ultra-sonication were successfully utilized to achieve a commercially valuable hyacinth fragrance, in addition to furan-based fuel additive precursors exhibiting a high conversion of glycerol and excellent selectivity within much less activation time (2 min).
Room temperature acetalization of glycerol to cyclic acetals over anchored silicotungstates under solvent free conditions
Narkhede, Nilesh,Patel, Anjali
, p. 19294 - 19301 (2014/05/20)
Heterogeneous catalysts comprising of parent Keggin type silicotungstate as well as monolacunary silicotungstate anchored to MCM-41 were synthesized and characterized by several physicochemical methods. A solvent free green route towards valorisation of glycerol via acetalization with benzaldehyde has been proposed. Both the catalysts showed very good activity as well as selectivity towards dioxolane derivatives within a short reaction time and at room temperature. The tuning of the acidity of the parent silicotungstate leads to an increase in the selectivity towards 1,3-dioxolane. The catalysts were also recycled up to four times without any significant loss in the conversion. The excellent performance of these mesoporous catalysts is attributed to their combination of acidity, wide pores and large specific surface area. the Partner Organisations 2014.
