Selective hydrogenolysis of glycerol to 1,2‐propanediol over highly active copper–magnesia catalysts: reaction parameter, catalyst stability and mechanism study

Abstract

BACKGROUND The surplus amount of glycerol (>1 million tons per year) from the biodiesel industry has received much attention in recent years for the production of alternative chemicals. The performance of x%Cu/MgO (x=5–50%) catalysts was investigated for selective hydrogenolysis of glycerol to 1,2‐propanediol (1,2‐PDO). The primary emphasis was given to the optimization of reaction parameters, reaction mechanism and catalyst stability. RESULTS The 35%Cu/MgO catalyst exhibited the maximum glycerol conversion of 96.6% with 92.6% selectivity to 1,2‐PDO at 210°C and 4.5 MPa H2 pressure. The high catalytic activity was attributed to the presence of bifunctional acidic–basic sites, and the synergetic interaction between copper nanoparticles and MgO support. To understand the reaction mechanism, the role of intermediates (1,2‐PDO, acetol, ethylene glycol) was investigated. Catalytic stability and reusability experiments were performed by repeating the reaction three times. The results of characterization of fresh and used catalysts demonstrated negligible deactivation of 35%Cu/MgO catalyst after successive reuse. CONCLUSION Cu/MgO catalyst played a significant role in enhancing the hydrogenolysis activity. The results demonstrated that glycerol conversion was rapidly increased with increasing reaction temperature, pressure and copper metal loading. The conversion of glycerol to 1,2‐PDO followed the dehydration–hydrogenation pathway and hydrogenolysis of C–C bonds was almost negligible. © 2015 Society of Chemical Industry

Glycerol hydrogenolysis using a Ni/Ce‐Mg catalyst for improved ethanol and 1,2‐propanediol selectivities

“…Surface basic sites were detected for the catalysts promoted with Zn and Mg, with more surface basic sites in the latter than in the former. The presence of surface basic sites in these catalysts supports the suggestion that basic sites play a key role in improved 1,2‐PDO selectivity . As Mg content in the catalysts was reduced, the total amount of surface basic sites was also reduced.…”

Selective Catalytic Transfer Hydrogenolysis of Glycerol to 2-Isopropoxy-Propan-1-Ol over Noble Metal Ion-Exchanged Mordenite Zeolite

“…Among the aforementioned reactions, hydrogenolysis of glycerol is a useful route for the production of important chemicals such as propane-1,3-diol, propane-1,2-diol, and ethylene glycol, which are commonly utilized in the synthesis of various valuable products, including pharmaceuticals, cosmetics, flavors, fragrances, and antifreezes [9,10]. Various noble and non-noble metals, including Pt, Rh, Ru, Pd, Cu, and Ni, supported on catalytic materials have been widely applied in common hydrogenolysis reactions as they are highly efficient for cleaving the various bonds in the glycerol molecule [11][12][13][14]. The use of bimetallic catalysts over a wide range of reaction temperatures and pressures has also been reported [15,16].…”

Procesos catalíticos para biorrefinerías: conversión de glicerol para la producción de biopropilenglicol

“…La mayor parte de los catalizadores soportados basados en Cu se han preparado mediante la técnica de impregnación a humedad incipiente, empleando Cu(NO3)2 como precursor [62,66,80,[168][169][170][171][172][173][174][175][176][177][178][179][180]. No obstante, esto, se han utilizado métodos de coprecipitación [66,[181][182][183], deposición-precipitación [184][185][186] e intercambio iónico [174,187]. En el estudio de catalizadores de Cu, se han empleado soportes basados en óxidos tales como γ-Al2O3 [168,171,173,177,180,188,189], SiO2 [66,90,184,190,191], ZnO [50,62,183], TiO2 [177,192], MgO [185] y Cr2O3 [80], zeolitas del tipo Y [182] y HZSM-5…”

“…No obstante, esto, se han utilizado métodos de coprecipitación [66,[181][182][183], deposición-precipitación [184][185][186] e intercambio iónico [174,187]. En el estudio de catalizadores de Cu, se han empleado soportes basados en óxidos tales como γ-Al2O3 [168,171,173,177,180,188,189], SiO2 [66,90,184,190,191], ZnO [50,62,183], TiO2 [177,192], MgO [185] y Cr2O3 [80], zeolitas del tipo Y [182] y HZSM-5 [193], sílices mesoporosas (HSM) [175], SBA-15 [176] e hidrotalcitas [181,193].…”

“…Para soportes básicos, como MgO [185] e hidrotalcitas [181,193], los reportes en bibliografía han indicado que una mayor basicidad aumenta los niveles de conversión de glicerol y selectividad a 1,2-PG. Además, en el caso de las hidrotalcitas, se ha observado que las partículas de Cu se dispersan fácilmente de forma homogénea, lo que contribuye a mejorar la performance del catalizador [181].…”