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Glycerol carbonate is one the glycerol derivatives which attracts attention for industrial applications. This review compares strategies for its synthesis, and their analyses lead to the conclusion that (indirect) procedures starting from glycerol- and/or CO2-derivatives are the most attractive. These are described and compared, taking criteria of industrial feasibility into account. As a result, the transesterification of dimethyl carbonate or ethylene carbonate with glycerol using uncalcined CaO as catalyst appears to be currently the most suitable industrial process. Finally, potential applications of glycerol carbonate as a multifunctional compound are exemplified.

The synthesis of lactic acid by alkaline hydrothermal conversion of glycerol at high glycerol concentrations under autogenous pressure is described. Temperature (250−290 °C), NaOH/glycerol molar ratio (1.1−1.75), glycerol concentration (2.5−3.5 M), and reaction time (30−250 min) have been the variables studied with temperature and NaOH/glycerol molar ratio having the major influence. An 84.5% lactic acid (as sodium lactate) yield is obtained at 280 °C and 90 min with a 2.5 M glycerol concentration and a 1.1 NaOH/glycerol molar ratio. The same yield is obtained starting from crude glycerol from biodiesel production as raw material. Sodium acrylate, oxalate and formate, and sodium carbonate have been identified as the main byproducts with carbonate being the major one. Several conversion routes based on the experimental results are proposed. A process for lactic acid separation based on electrodialysis is outlined.

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