Ionic-liquid-catalyzed decarboxylation of glycerol carbonate to glycidol

• Published in: Journal of catalysis Vol. 297; pp. 248 - 255
• Main Authors: Choi, Ji Sik, Simanjuntak, Fidelis Stefanus Hubertson, Oh, Ji Young, Lee, Keun Im, Lee, Sang Deuk, Cheong, Minserk, Kim, Hoon Sik, Lee, Hyunjoo
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01-01-2013; Elsevier; Elsevier BV
• Subjects: acidity; anions; Catalysis; catalysts; Chemical reactions; Chemistry; Decarboxylation; Exact sciences and technology; Fourier transform infrared spectroscopy; General and physical chemistry; Glycerol; Glycerol carbonate; Glycidol; hydrogen bonding; iodides; Ionic liquids; nitrates; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; yields; zinc; Glycerol carbonate; Glycerol; Ionic liquids; Glycidol; Decarboxylation; Catalytic reaction; Carbonates; Ionic liquid
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2012.10.015

Decarboxylation of glycerol carbonate was catalyzed by ionic liquids.
Computation calculation revealed that the first step is the anion-assisted ring-opening of glycerol carbonate followed by the ring closure, resulting in the formation of glycidol. [Display omitted]
► Glycidol was obtained in high yield from the decarboxylation of glycerol carbonate. ► The catalytic performance of ILs was strongly affected by the basicity of the anions of ILs. ► The use of Lewis acidic metal salt with an IL improved the yield and selectivity of glycidol. ► The driving force is the preferential interaction of an IL with the -OH group of glycerol carbonate.
Decarboxylation of glycerol carbonate (GLC) to produce 2,3-epoxy-1-propanol (glycidol) was conducted using various kinds of ionic liquids (ILs) as catalysts. ILs bearing an anion with medium hydrogen-bond basicity such as NO3- and I− exhibited the higher glycidol yields than those having an anion with low or strong hydrogen-bond. FT-IR spectroscopic analysis shows that both GLC and glycidol interact with anions of ILs through their hydroxyl groups. It was possible to improve the yield of glycidol when a zinc salt with a medium Lewis acidity was co-present along with an IL. The yield of glycidol was greatly increased up to 98% when the decarboxylation was conducted in the presence of a high-boiling aprotic solvent. Computational calculations on the mechanism using 1-butyl-3-methylimidazolium nitrate as a catalyst revealed that the first step is the NO3--assisted ring-opening of GLC followed by the ring closure, resulting in the formation of a 3-membered ring intermediate species.