Glycerol: A green solvent for synthetic chemistry

Glycerol is a biobased, biodegradable liquid known for its non-toxic, non-hazardous, non-volatile, and water-soluble properties, making it valuable in various applications. Derived from biodiesel production, it constitutes about 10% of the weight alongside fatty acid alkyl esters. Its availability and unique properties make glycerol an economically attractive and safe solvent for organic syntheses. Solvents, critical in chemical processes, require recycling or disposal, often via incineration. Eco-friendly profile of glycerol offers significant advantages over traditional solvents. Research has highlighted the role of glycerol as a hydrogen donor in metal-catalyzed transfer hydrogenation reactions, reducing compounds and aiding in metal nanoparticle preparation. Since 2010, glycerol has been recognized for its solvent capabilities in key organic reactions, such as C-C bond formations (e.g., Suzuki-Miyaura, Heck-Mizoroki), C-N, and C-P bond formations, among others. It also facilitates multicomponent reactions, showing high yields with various catalyst systems. The potential of glycerol extends to catalyst recyclability and sustainability in chemical processes. However, more systematic studies and modeling are needed to fully leverage its benefits. Exploring the use of crude glycerol could enhance cost-effectiveness and sustainability, and transitioning to continuous flow systems could improve productivity. Addressing these aspects can lead to broader and more sustainable glycerol utilization in the future.