RESUMO
Cu-Zn-Al catalysts were prepared using microwave-assisted process and co-precipitation methods. The prepared catalysts were characterized by XRD, BET, XPS and TPD of ammonia and their catalytic activity for the hydrogenolysis of glycerol to propylene glycol was also examined. The XRD patterns of Cu/Zn/Al mixed catalysts show CuO and ZnO crystalline phase regardless of preparation method. The highest glycerol hydrogenolysis conversion is obtained with the catalyst having a Cu/Zn/Al ratio of 2:2:1. Hydrogen pre-reduction of catalysts significantly enhanced both glycerol conversions and selectivity to propylene glycol. The glycerol conversion increased with an increase of reaction temperature. However, the selectivity to propylene glycol increased with an increase of temperature, and then declined to 30.5% at 523 K.
Assuntos
Glicerol/química , Metais Pesados/química , Nanoestruturas/química , Propilenoglicol/química , Catálise , Técnicas de Química Sintética , Temperatura Alta , Hidrogênio , Micro-Ondas , Tamanho da Partícula , Difração de Raios XRESUMO
A functionalized isoreticular metal organic framework material, F-IRMOF-3, having a quaternary ammonium group was prepared by fast precipitation and solvothermal method. The synthesized MOFs exhibited good catalytic performance in the synthesis of glycerol carbonate (GC) from glycerol and urea. F-IRMOF-3 having a larger alkyl chain structure and a more nucleophilic counter anion than the synthesized congeners, exhibited better reactivity in the synthesis of GC. The introduction of a ZnO defect into the F-IRMOF-3 structure by fast precipitation was more advantageous for the glycerolysis of urea than the conventional solvothermal method because of the incorporation of acid-base bifunctional active sites by the former method. The effects of reaction parameters such as temperature, reaction time, catalyst loading, and degree of vacuum on the reactivity were also investigated. The F-IRMOF-3 catalyst can be easily recovered and reused without considerable loss of its initial activity.