First Evidence of the Double-Bond Formation by Deoxydehydration of Glycerol and 1,2-Propanediol in Ionic Liquids

Andrea Mascitti; Giuseppe Scioli; Lucia Tonucci; Valentino Canale; Raimondo Germani; Pietro Di Profio; Nicola d'Alessandro

doi:10.1021/acsomega.2c01803

First Evidence of the Double-Bond Formation by Deoxydehydration of Glycerol and 1,2-Propanediol in Ionic Liquids

ACS Omega. 2022 Aug 1;7(32):27980-27990. doi: 10.1021/acsomega.2c01803. eCollection 2022 Aug 16.

Authors

Andrea Mascitti¹, Giuseppe Scioli¹, Lucia Tonucci², Valentino Canale³, Raimondo Germani⁴, Pietro Di Profio³, Nicola d'Alessandro¹

Affiliations

¹ Department of Engineering and Geology, "G. d'Annunzio" University of Chieti-Pescara, Via dei Vestini, 31, 66100 Chieti, Italy.
² Department of Philosophical, Educational and Economic Sciences, "G. d'Annunzio" University of Chieti-Pescara, Via dei Vestini, 66100 Chieti, Italy.
³ Department of Pharmacy, "G. d'Annunzio" University of Chieti-Pescara, Via dei Vestini, 66100 Chieti, Italy.
⁴ Department of Chemistry, Biology and Biotechnology, University of Perugia, Via Elce di sotto, 06123 Perugia, Italy.

Abstract

Deoxydehydration (DODH) reaction of glycerol (GL) and 1,2-propanediol (1,2-PD), in ionic liquids (ILs), catalyzed by methyltrioxorhenium (MTO) and Re₂O₇, was studied in detail. To better understand the ability of ILs to improve the catalytic performance of the rhenium catalyst, several experiments, employing eight different cations and two different anions, were carried out. Among the anions, bis(trifluoromethylsulfonyl)imide (TFSI) appears to be more appropriate than PF₆ ^-, for its relatively lower volatility of the resulting IL. Regarding the choice of the most appropriate cation, the presence of a single aromatic ring seems to be a necessary requirement for a satisfying and convenient reactivity. With the aim to extend the recyclability of the catalyst, experiments involving the readdition of polyol to the terminal reaction mixture were carried out. Worthy of interest is the fact that the presence of the IL prevents the inertization process of the catalyst, allowing us to obtain the alkene also after a readdition of fresh polyol.