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Catalysis is an important tool in obtaining a range of derivative products from renewable sources, such as ethanol. Solid-state dealumination using ammonium hexafluorosilicate on the BEA zeolite under the treatment at temperature of 190 °C, 70 mol% dealumination in the presence of humidity and washing with buffer solution at 25 °C generated larger pores. The absence of washing procedure for the same sample resulted in pore blockage. Ethanol dehydration reactions showed conversion of 72% (64% ethylene and 8% diethyl ether) for this sample at 300 °C and high weight hourly space velocity (WHSV, 3247 h-1), whereas, at the same temperature but at a low WHSV (57 h-1), the conversion was 88% (49% ethylene and 39% diethyl ether). Dealuminated BEA zeolite presented better diffusion conditions, higher hydrophobicity and generated larger pores. Impregnation with H 3 PW 12 O 40 , H 4 SiW 12 O 40 and Nb 2 O 5 explained the selectivity, showing that Lewis acid sites from Nb 2 O 5 favored the diethyl ether production.

In this work, we investigated the role of solid-state dealumination by (NH4)2SiF6 (25% Al removal and 13% Si insertion), the impregnation of niobium (10, 18, and 25 wt. %) on dealuminated *BEA (DB) zeolite and their catalytic properties in ethanol and xylose transformations. Among all the studied catalysts, 18%Nb-DB showed increased mesoporosity and external areas. A leveling effect in the number and strength of the proposed two sites (Brønsted and Lewis) present in the catalyst (n1 = 0.24 mmol g−1, −ΔH1 = 49 kJ mol−1, and n2 = 0.20 mmol g−1, –ΔH2 = 42 kJ mol−1) in the catalyst 18%Nb-DB, might be responsible for its good activity. This catalyst presented the highest selectivity for diethyl ether, DEE (97%) with 61% conversion after 50 ethanol pulses at 230 °C (turnover number, TON DEE = 1.15). These features allowed catalytically fruitful bonding of the ethanol molecules to the neighboring sites on the channels, facilitating bimolecular ether formation through a possible SN2 mechanism. The same catalyst was active and selective for transformation of xylose at 180 °C, showing 64% conversion and 51% selectivity for furfural (TON Furfural = 24.7) using water as a green solvent.

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