Progress of Catalytic Valorization of Bio-Glycerol with Urea into Glycerol Carbonate as a Monomer for Polymeric Materials

Scheme 7

Lattice structure of (a) ordered and disordered spinel ZnAl₂O₄ phase, (b) c-ZnAl₂O₄, (c) c-ZnAlO, and (d) p-ZnAlO [57]. Reproduced from Ref. [57] with permission, Copyright 2019 Elsevier.

(a)

(b)

(c)

(d)