Optimizing Glycerol Transesterification with Propylene Carbonate

The transesterification process of glycerol with propylene carbonate was executed within a carefully controlled glass reactor, ensuring a homogeneous reaction phase at temperatures exceeding 70 °C. The experimental protocol commenced with the introduction of 12 mL of glycerol into the reactor, gradually heating it to the desired reaction temperature while maintaining continuous stirring at 600 rpm. The reaction initiation involved the addition of 40 mL of propylene carbonate and the catalyst into the reactor.
To identify the most suitable basic catalyst, a comprehensive exploration of K₂CO₃’s impact on smectite and variations in the catalyst’s calcination temperature was undertaken. Once the optimal catalyst was determined, a detailed investigation was conducted under various reaction conditions. This included systematic adjustments to the reaction temperature across a range of values (344, 354, 364, 374, 384, and 394 K), fine-tuning the molar ratio of propylene carbonate to glycerol (ranging from 1.5:1 to 3:1), and evaluating different weight ratios of catalyst to glycerol (spanning from 2% to 6 wt%). All experiments were conducted under atmospheric pressure conditions, and the reaction duration was consistently set at 6 h.
It is noteworthy that the observed yields remained consistent across varying stirring speeds within the range of 400–1000 rpm, thereby ensuring that, if the stirring rate remained at a constant 600 rpm throughout the experimental process, no mass transfer limitations would be present. This study design aimed to unveil the optimal catalyst and reaction conditions for the transesterification of glycerol with propylene carbonate (Figure 19).