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Efficient Synthetic Protocols in Glycerol under Heterogeneous Catalysis
Author(s) -
Cravotto Giancarlo,
Orio Laura,
Gaudino Emanuela Calcio,
Martina Katia,
Tavor Dorith,
Wolfson Adi
Publication year - 2011
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201100106
Subject(s) - glycerol , solvent , catalysis , chemistry , organic chemistry , benzaldehyde , transesterification , green chemistry , reaction mechanism
The massive increase in glycerol production from the transesterification of vegetable oils has stimulated a large effort to find novel uses for this compound. Hence, the use of glycerol as a solvent for organic synthesis has drawn particular interest. Drawbacks of this green and renewable solvent are a low solubility of highly hydrophobic molecules and a high viscosity, which often requires the use of a fluidifying co‐solvent. These limitations can be easily overcome by performing reactions under high‐intensity ultrasound and microwaves in a stand‐alone or combined manner. These non‐conventional techniques facilitate and widen the use of glycerol as a solvent in organic synthesis. Glycerol allows excellent acoustic cavitation even at high temperatures (70–100 °C), which is otherwise negligible in water. Herein, we describe three different types of applications: 1) the catalytic transfer hydrogenation of benzaldehyde to benzyl alcohol in which glycerol plays the dual role of the solvent and hydrogen donor; 2) the palladium‐catalyzed Suzuki cross‐coupling; and (3) the Barbier reaction. In all cases glycerol proved to be a greener, less expensive, and safer alternative to the classic volatile organic solvents.