First multicomponent reaction exploiting glycerol carbonate synthesis

The first example of the use of ammonia, the waste material of the bulk glycerol carbonate (GC) production, for the formation of another valuable organic molecule, a 1,4-dihydropyridine (1,4-DHP), by an in line two reactor system was presented. Two Q-tube reactors, one for the urea glycerolysis and the other for the Hantzsch reaction, were used, connected through a PTFE tube. Urea glycerolysis using La2O3 as heterogeneous catalyst, under N-2 pressure or in vacuum conditions, was optimized. A catalyst free and organic solvent free condition was selected to realize a Hantzsch reaction in an ecofriendly way. Glycerol carbonate and a 1,4-dihydropyridine were synthesized in two subsequent reactions, converting wastes into added value products. The best result was that glycerol carbonate was obtained at 36% with 77% of selectivity, and at the same time the Hantzsch product was synthesized with a 75% of yield. (C) 2018 Elsevier Ltd. All rights reserved.