Glycerol acetals and ketals as possible diesel additives. A review of their synthesis protocols

With the rapid development of the biodiesel industry all over the world, a large surplus of glycerol has been created, so economic uses of glycerol for value-added products are critical for the sustainability of the biodiesel industry. One of the main interests in recent years for glycerin utilization is its conversion in acetals and ketals, with the potential to be used as fuel additives. Glycerol acetals and ketals can be synthesized through the acid-catalyzed reaction of glycerol with aldehydes and ketones, respectively. This paper reviews different approaches and techniques used to obtain glycerol acetals and ketals, regarding the reactor design, catalyst design and the effect of different parameters in the reaction system.