Highly efficient and robust Cu catalyst for non-oxidative dehydrogenation of ethanol to acetaldehyde and hydrogen

While acetaldehyde is industrially produced in the Wacker process by homogeneous catalysts, a heterogeneous catalyst is so far elusive due to rapid deactivation stemming from metal sintering and coke formation. This work reports on a highly efficient, robust and stable Cu/SiO2 catalyst for the non-oxidative dehydrogenation of ethanol prepared by the ammonia evaporation method. The highly dispersed Cu-particles are distinguished by outstanding thermal stability with very little sintering up to 600 °C. This was attributed to the strong interactions between the copper crystallites and SiO2 arising from the intermediately formed copper phyllosilicate phase. Deactivation due to coke formation was successfully addressed by optimizing the metal loading. The CHx/Cu ratio in the used catalyst decreased by a factor of 10 as the copper loading was increased from 0.5 to 10 wt%. Samples with Cu ≥ 10 wt% demonstrated excellent activity of > 90% ethanol conversion and > 98% acetaldehyde selectivity with no observable deactivation for up to 500 h on-stream at 280 °C and a GHSV of 8895 h−1 (34,930 ml g-1h−1).