Mechanism of <scp>CaO</scp> catalyst deactivation with unconventional monitoring method for glycerol carbonate production via transesterification of glycerol with dimethyl carbonate

Glycerol carbonate (GC) was synthesized by transesterification of glycerol with dimethyl (DMC) using calcium oxide (CaO) derived from eggshell as a catalyst. The best results 96% conversion and 94% GC yield were achieved under the following reaction conditions: 0.08 mole ratio CaO to glycerol, 1:2.5 DMC, 60°C temperature, 3 hours time. As expected, showed deteriorated catalytic performance when recycling observed rapid decrease in yield. This research that active phase first converted methoxide (Ca[OCH3]2) diglyceroxide (Ca[C3H7O3]2) finally (CaCO3) which can be confirmed XRD patterns. According transformation, basicity decreased 0.482 mmol/g 0.023 mmol/g, basic strength altered strong (15.0 < H_ 18.4) weak (7.2 9.8), resulting lower activity consecutive runs. Despite fact selectivity almost 100%, products (methanol GC) not obtained their stoichiometric extents corresponded catalyst transformation CaCO3. mechanism catalyzed based on condensation proposed, situ formation water-derivative species hypothesized cause transformation. could react DMC water, generating methanol enabled unconventional monitoring deactivation checking if higher than 2:1 its ratio. It also demonstrated calcination post-run at 900°C exhibited constant activity, stoichiometry (2:1) for least 4 times use.