Influence of the carrier and composition of active phase on physicochemical and catalytic properties of CuAg/oxide catalysts for selective hydrogenolysis of glycerol

Abstract

The aim of the present study is to investigate the influence of the support and composition of the active bimetallic phase on both the physicochemical and catalytic properties of catalysts for use in glycerol hydrogenolysis reaction. Two series of catalysts with different amounts of copper oxide and/or silver supported on Al 2 O 3 or TiO 2 oxides were prepared. To determine the physicochemical properties of the catalysts, the following techniques were used: Brunauer-Emmett-Teller, reactive N 2 O adsorption, X-ray diffraction, and temperature-programmed reduction TPR-H 2 . Physicochemical characterization revealed that addition of silver modifies the redox properties of the catalysts containing copper oxide and influences their specific surface area. It was found that the type of carrier determines the catalytic activity and selectivities for desired products, strongly influencing their distribution. The Al 2 O 3 -supported catalysts were much more selective for 1,2-propanediol, whereas 1-propanol was the main reaction product for the titania-supported catalysts. The best catalysts (6Cu/Al and 2Cu/Ti) achieved 38 % glycerol conversion with 71 % selectivity for 1,2-propanediol and 44 % conversion with 62 % selectivity for 1-propanol, respectively.

Synthesis and characterization of Zn doped WO3 nanoparticles: photocatalytic, antifungal and antibacterial activities evaluation

“…The selection of proper method for the preparation of nanoparticles (NPs) depends upon binding sites specificity, compatibility with bio-molecules, solubility, shape, size, surface properties and degree of biodegradability. For many decades, the NPs have been used widely for different purposes and doping of metal oxides have been used to enhance the properties for applications in different fields like solar cells, photocatalysis and photodegradation and sensors etc [5][6][7]. NPs have been synthesized using different approaches and table 1 shows summary of methods employed for synthesis of WO 3 NPs and their doping [8][9][10][11][12][13][14][15][16][17].…”

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].…”

“…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 los soportes ácidos, como ZnO [50,62,183], Cr2O3 [80], γ-Al2O3 [168,171,173,177,180,188,189], y las zeolitas del tipo Y [182], se ha reportado que los sitios ácidos del soporte favorecen la deshidratación del glicerol a AcOH que luego se hidrogena sobre los sitios metálicos del Cu, aunque la fase activa de Cu también genera la ruptura del enlace C-O.…”

“…Por otro lado, cuando la acidez del soporte es elevada, como en el caso de la zeolita HZSM-5 [193], la selectividad a 1,2-PG disminuye debido a la deshidratación de glicerol a acroleína. En otros casos, el tipo de sitios ácidos no favorece la formación de 1,2-PG, como es el caso del TiO2 [177,192], en donde el producto principal es 1-propanol (1-POH).…”