Understanding the surface and structural characteristics of tungsten oxide supported on tin oxide catalysts for the conversion of glycerol

Abstract

Catalysts with varying WO 3 content on SnO 2 were prepared and characterized by X-ray diffraction, in situ Raman spectroscopy, X-ray photoelectron spectroscopy and temperature programmed desorption of NH 3 . In situ Raman analysis reveals the presence isolated monomers and polymeric species of WO 3 . These catalysts were evaluated for the conversion of glycerol into value added chemicals. Etherification of glycerol with tertiary butanol and preparation of glycerol carbonate from glycerol and urea are studied over these catalysts. The catalytic activity results suggest that the glycerol conversion and selectivity depends on the morphology of WO 3 which in turn is related to its content in the catalyst. The catalysts with 5 wt.% of WO 3 on SnO 2 resulted in high dispersion with larger number of strong acidic sites. The selectivity in the glycerol etherification is related to the nature of the catalyst and reaction time. These catalysts also exhibited high activity for synthesis of glycerol carbonate. The effect of various reaction parameters was studied to optimize the reaction conditions. The catalysts also exhibited consistent activity upon reuse.

Recent Development of Heterogeneous Catalysis in the Transesterification of Glycerol to Glycerol Carbonate

“…Traditional chemical syntheses are the most widely used methods in the large-scale preparation of glycerol carbonate directly from glycerol. With glycerol used as starting material, glycerol carbonate is obtained via chemical processes, such as carbonation with carbon dioxide [26][27][28] or carbon monoxide in the presence of oxidants [29,30], trans-carbonation with phosgene [21] or urea and its derivatives [31][32][33][34][35], and transesterification with simple carbonate esters (Figure 3) [15][16][17][18][19][20]. Transesterification of glycerol has significant advantages over other methodologies in the following aspects: (1) avoiding the employment and release of poisonous gases and toxic reagents; (2) higher activity and selectivity; (3) shorter reaction time and higher conversion; (4) free of solvent and simple separation of catalyst; and (5) environmentally friendly and intrinsically safe.…”

Nano-sized mesoporous phosphated tin oxide as an efficient solid acid catalyst

“…25 Tin oxide is one of the most attractive functional materials because of its potential applications, mainly as a catalyst and as a carrier in supported catalysts. 26 Besides its intrinsic nonstoichiometry and crystal defects, tin oxide nanoparticles can be used more efficiently as a catalyst due to the faster migration of the oxide ions within the SnO 2 nanoparticles to increase the surface to volume ratio. Many authors have used high valence cations of metal oxide to promote the thermal stability and catalytic property of pure tin oxide.…”

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

“…Sn-W catalyst with a 2 : 1 molar ratio calcined at 500℃ showed the best catalytic performance in terms of 52% of glycerol conversion with >95% GC selectivity. Similarly, different WO 3 contents supported on SnO 2 catalytic materials were prepared and employed for GC synthesis [100]. In situ Raman technology revealed the existence of isolated monomers and polymeric species of WO 3 .…”