1,2-Isopropylidene Glycerol Carbonate: Preparation, Characterization, and Hydrolysis

Abstract  Utilization of excess glycerol supplies derived from the burgeoning biodiesel industry is of major importance to the oleochemical industry as the economic viability of the biodiesel and oleochemical industries are closely linked to glycerol prices. Carbonates based on glycerol, such as glycerol carbonate, are gaining prominence due their simple preparation, interesting properties and chemistry. Herein, the synthesis, physical properties, and chemistry of an interesting glycerol-based carbonate (4, bis[(2,2-dimethyl-1,3-dioxolan-4-yl)methyl] carbonate; 1,2-isopropylidene glycerol carbonate or solketal carbonate) is reported. Carbonate interchange reaction between solketal (isopropylidene glycerol) and diethyl carbonate in the presence of sodium methoxide catalyst gave solketal carbonate, 4, in 65–70% isolated yields. Carbonate 4 was characterized using Fourier transform infrared spectroscopy (FTIR), 1H and 13C nuclear magnetic resonance spectroscopy (NMR), and gas chromatography–mass spectrometry (GC/MS). The kinematic viscosity at 40 °C, refractive index, and melting point of 4 were determined to be 26.7 mm2/s, 1.4460, and below −50 °C, respectively. Using a high frequency reciprocating rig (HFRR) testing apparatus neat 4 was shown to have lubricity properties similar to fatty acid esters. Hydrolysis of the isopropylidene groups converted carbonate 4 into polyol 6, bis(2,3-dihydroxypropyl) carbonate in good yields (84%). Carbonate polyol 6 was characterized by 1H and 13C NMR and represents a potentially novel polyol component that may be useful in the syntheses of interesting carbonate containing esters and polymers.