Glycerol utilization: solvent-free acetalisation over niobia catalysts

With increasing biodiesel production, availability of glycerol is expected to increase. New processes are needed for converting this surplus glycerol to value-added chemicals. In this work, we used niobia catalysts for the liquid-phase acetalisation of glycerol without using any solvent. High conversions were achieved (∼80%), though water was present in the reaction system. The calcination temperature changed the strength as well as the nature of acidity of the samples. Samples with higher Brønsted acid strength exhibited higher catalytic performance. The results show that niobia is a water tolerant, reusable catalyst for glycerol acetalisation.