Organocatalytic Cycloaddition of CO2 to Glycidol: the Dual Role of Substrate and Catalyst Played by a Hydroxy-Functionalized Epoxide Francesco Della Monica,1,2Antonio Buonerba, 1,2 Stefano Milione, 1,2Carmine Capacchione,, 1,2 Alfonso Grassi1,2 1Dipartimento di Chimica e Biologia "Adolfo Zambelli", Università degli Studi di Salerno, via Giovanni Paolo II, 84084 Fisciano(SA), Italy 2Interuniversity Consortium on Chemical Reactivity and Catalysis, CIRCC, via Celso Ulpiani 27, 70126 (BA), Italy *Corresponding author: email@example.com Keywords: Carbon dioxide, Epoxides, Glycerolcarbonate Abstract The coupling of carbon dioxide with epoxides represents a very attractive reaction for the possibility of recovering a waste, namely CO2, by means of a 100% atom-economical process leading to value added products such as cyclic carbonates. In the last decade, the development of CO2 chemistry parallely to the increasing production of biodiesel from vegetable oils offered to the market a new cheap raw material as glycerol whose decreasing price has triggered a growing interest in the efficient conversion of this molecule to value added commodities. Among the possible derivatives, glycerol carbonate (GC) is a particularly interesting target since it has a potential application as low Volatile Organic Compound (VOC), a bio-based alternative to organic solvents from non-renewable resources. Scheme 2. Synthesis of glycerol carbonate (GC) from glycidol and CO2 Here we report on the conversion of glycidol to glycerol carbonate (GC) in excellent yields (99%) and short reaction time (3h), by coupling with CO2 in the presence of tetrabutylammonium bromide (TBAB) as activator and under mild reaction conditions (T = 60°C, P(CO2) = 1MPa). The unusual reactivity of glycidol compared to other epoxides is due to the presence of the hydroxyl functionality. DFT calculations supported by 1H NMR experiments indeed revealed that the unique behaviour of this epoxide is due to the formation of a dimeric structure driven by intermolecular hydrogen bonds that activates the oxirane ring toward the nucleophilic attack of the bromide anion, leading to the formation of GC. Furthermore, the glycidol/TBAB binary system acts as efficient organocatalyst for the coupling of CO2 with other epoxides. References  (a) C. Martín, G. Fiorani and A. W. Kleij, ACS Catal., 2015, 5, 1353-1370; (b) J. W. Comerford, I. D. V. Ingram, M. North and X. Wu, Green Chem., 2015, 17, 1966-1987.  M. O. Sonnati, S. Amigoni, E. P. T. de Givenchy, T. Darmanin, O. Choulet and F. Guittard, Green Chem., 2013, 15, 283–306.
|Titolo:||Organocatalytic Cycloaddition of CO2 to Glycidol: the Dual Role of Substrate and Catalyst Played by a Hydroxy-Functionalized Epoxide|
GRASSI, Alfonso (Corresponding)
|Data di pubblicazione:||2016|
|Appare nelle tipologie:||4.1 Contributi in Atti di convegno|