The CsHCO3 catalyzed liquid-phase etherification of glycerol to oligomers was studied in a discontinuous batch reactor at 260 °C under normal pressure. Concentration vs. time profiles at 0.1, 0.2 and 0.4 wt% CsHCO3 addition confirmed the consecutive reaction of diglycerol to higher oligomers. Maximum concentration of the target product, linear diglycerol, was observed after intermediate reaction times of 8 h. Independent of the catalyst concentration, a unique conversion-selectivity profile was observed with 100% linear diglycerol at low glycerol conversion but only 10% at complete glycerol conversion. The α,α′ configurational diglycerol isomer prevailed and was preferentially oligomerized. Interconversion of the configurational isomers was not observed. The conversion of glycerol obeyed a 1st order kinetics.
- Cesium hydrogencarbonate
- Linear diglycerol