Sulfated Zirconia with Different Crystal Phases for the Production of Ethyl Levulinate and 5‐Hydroxymethylfurfural

Abstract

Distinct crystal phases of an oxide affect the configuration of surface atoms, which might further affect coordination with sulfate during sulfonation for the preparation of SO42−/MxOy type of acid catalyst. Herein, such an effect is investigated with zirconia of the tetragonal or monoclinic phase as the model catalysts. The results show that sulfonation inhibits the transformation of zirconia from the tetragonal phase to the monoclinic phase, whereas the varied phase of zirconia also affects the bonding patterns of sulfate species with zirconia in sulfonation. The sulfated zirconia of monoclinic phase contains more abundant acidic sites and more Brønsted acid sites than that of sulfated zirconia of tetragonal phase. Consequently, the sulfated zirconia of monoclinic phase is more active than the sulfated zirconia of tetragonal phase for the conversion of furfuryl alcohol in ethanol and conversion of fructose in dimethyl sulfoxide, achieving the yield of ethyl levulinate of 96.4% and a high yield of 5‐hydroxymethylfurfural. The sulfated zirconia is not stable in protic solvent due to the leaching of sulfur species and the change in configurations of the sulfate species and the zirconium species, but in the aprotic solvent, they show good stability and recyclability.

Clay as support for copper catalysts for the hydrogenation of furfural and phenolics

“…The characteristic peak at 3423 cm −1 was characteristic of O‐H bending vibration. The absorption peaks at 3925, 2843 and 1387 cm −1 were attributed to C‐H stretching vibration, the peak at 1642 cm −1 to the H‐OH bending vibration of water . The strong and wide absorption band at 1052 cm −1 was attributed to Si‐O‐Si antisymmetric stretching vibration.…”

“…The absorption peaks at 3925, 2843 and 1387 cm −1 were attributed to C-H stretching vibration, the peak at 1642 cm −1 to the H-OH bending vibration of water. 48 The strong and wide absorption band at 1052 cm −1 was attributed to Si-O-Si antisymmetric stretching vibration. The absorption peaks at 1052, 781, 699, 529 and 471 cm −1 were attributed to Si-O symmetrical stretching vibration, and the bond peak at 912 cm −1 to Si-OH bending vibration.…”

Butane Isomerization as a Diagnostic Tool in the Rational Design of Solid Acid Catalysts

“…The nature of the crystal phase will result in the exposure of different zirconium bonding environments [104]. This inevitably effects how the zirconia interacts with sulfur species (SO 4 2− ) during sulfation and the resulting active sites [105]. Typical synthetic routes for SZ catalysts produce microporous materials (pore diameter < 2 nm), with surface areas ranging from 100-120 m 2 /g [106], which are well suited to acid catalyzed transformations of small molecules [61].…”

Sulfated TiO2 nanosheets catalyzing conversion of biomass derivatives: influences of the sulfation on distribution of Brønsted and Lewis acidic sites

“…17 HMF, as a valuable chemical, has also been paid increasing attention for its production and extensive applications. 18,19 HMF can be obtained from the hydrolysis of cellulose in biomass or biomass derivatives, C6 sugars, 20 which can be further upgraded to highly valuable compounds such as dimethylfuran, 21,22 tetrahydrofuran-dimethanol 23 and levulinic acid/esters, 24 which can be used as suitable fuel additives. 25 As mentioned above, the productions of LA and HMF involve the acidic catalysis process, and acid catalysts play prominent roles for their effective and selective productions.…”

“…Taking glucose as an example, the process involves the isomerization of glucose to fructose, the dehydration of fructose to 5‐hydroxymethylfurfural (HMF) and the further decomposition of HMF to LA in water or to levulinic esters in alcohol solvents . HMF, as a valuable chemical, has also been paid increasing attention for its production and extensive applications . HMF can be obtained from the hydrolysis of cellulose in biomass or biomass derivatives, C6 sugars, which can be further upgraded to highly valuable compounds such as dimethylfuran, tetrahydrofuran‐dimethanol and levulinic acid/esters, which can be used as suitable fuel additives .…”