Direct ethanol condensation to diethyl acetal in the vapour phase at atmospheric pressure over CuNP/SBA-15 catalysts

Abstract

Of the biomass valorization technologies, bioethanol production and its selective conversion to diethyl acetal is of utmost importance to meet the increasing demand for bio-fuel additives. Direct synthesis of diethyl acetal in a single step from bioethanol using SBA-15-supported copper nanoparticle (CuNP/SBA-15) catalysts without using hydrogen acceptors and high pressure has been achieved as an alternative to the age-old two-step process via (i) partial oxidation of ethanol to acetaldehyde and (ii) acetaldehyde acetalization with ethanol. The prepared CuNP/SBA-15 catalysts with the SBA-15 support and copper nitrate (Cu (NO₃)₂·H₂O) were characterized by using N₂ adsorption, SEM, TEM, XRD, FT-IR, TPD of NH₃, H₂-TPR and N₂O pulse chemisorption techniques. Analysis of the results showed the physico-chemical characterestics of these catalysts responsible for the acceptorless partial oxidation of ethanol to acetaldehyde and its acetalization with ethanol to yield diethyl acetal with high selectivity.