Catalytic conversion of glycerol for sustainable production of solketal as a fuel additive: A review

The exponential growth of biodiesel industries all around the world has produced a large amount of glycerol as a byproduct, which must be valorized for the sustainability of the biodiesel industry. Ketalization of glycerol with acetone to synthesize solketal-a potential fuel additive is one of the most promising routes for valorization of glycerol. In this article, state-of-the-art of glycerol ketalization is reviewed, focusing on innovative and potential technologies towards sustainable production of solketal. The glycerol ketalization processes developed in both batch and continuous reactors and performance of some typical catalysts are compared. The mechanisms for the acid-catalyzed conversion of glycerol into solketal are presented. The main operation issues related to catalytic conversion of crude glycerol in a continuous-flow process and the direct use of crude glycerol are discussed. (C) 2015 Elsevier Ltd. All rights reserved.