Transesterification of Glycerol to Glycerol Carbonate Over Alkali Carbonate‐Carbon Hybrid Catalysts

Abstract Sodium‐containing polymers and rapeseed meal were utilized as precursors for carbon‐inorganic hybrid catalysts offering the advantages of easily accessible raw materials and a straightforward preparation process. The resulting catalysts comprised inorganic components dispersed within a carbonaceous matrix and exhibited basic properties. These catalysts were employed in synthesizing glycerol carbonate (a versatile building block reagent) from glycerol and dimethyl carbonate under mild conditions. The most effective catalyst was obtained by pyrolyzing sodium alginate, achieving a glycerol conversion of approximately 93% and a glycerol carbonate yield of about 57% within just 0.5 h. Catalysts derived from sodium polyacrylate or rapeseed meal activated with Na 2 CO 3 also demonstrated excellent performance, albeit requiring slightly longer reaction times to achieve comparable results. In contrast, the catalyst prepared by pyrolyzing rapeseed meal with K 2 CO 3 exhibited very high glycerol conversion but primarily produced glycidol as the main product. The samples showed good stability over successive catalytic cycles, and the carbonaceous matrix was proposed to play a crucial role in stabilizing the active phase, potentially reducing leaching, and improving the catalyst reusability. It also promotes the enhanced selectivity toward glycerol carbonate.