Reconstruction of calcined MgAl- and NiMgAl-layered double hydroxides during glycerol dehydration and their recycling characteristics

MgAl- and NiMgAl-layered double hydroxides (LDHs) were prepared by the co-precipitation method. On calcination MgAl and NiMgAl mixed oxides were formed. Crystalline MgO and NiO could be identified, while aluminium ions were well-dispersed on these oxides. The mixed oxides were effective in the transformation of glycerol to currently more valuable products like acetol (hydroxyacetone) and acrolein. Acetol was found to be the main product and some part was further dehydrated to acrolein. During the reaction, full reconstruction of the LDH structure occurred. The used catalysts could be reactivated by repeated calcination.