Aldol condensation of acetaldehyde for butanol synthesis: A temporal analysis of products study
Joachim Pasel, Johannes Häusler, Dirk Schmitt, Helen Valencia, Joachim Mayer, Ralf Peters
Abstract
The catalytic upgrading of CO2-based ethanol into valuable products, such as higher alcohols, is of increasing interest. Carbon-neutral n-butanol can substitute major fractions of conventional gasoline in the transport sector of the future. A promising synthesis path towards n-butanol is the Guerbet reaction, in which the homo aldol condensation of acetaldehyde constitutes an important intermediate step, which was investigated using the Temporal Analysis of Products methodology. This investigation employed the lanthanide oxides Dy2O3, Eu2O3, and Er2O3, supported on activated carbon due to their varying basic characteristics. In addition to the aldol condensation of acetaldehyde yielding butanol, its decomposition into CO, CH4, and H2 also occurred. Furthermore, acetaldehyde pulsing onto the catalyst surface of Dy2O3/C also lead to the formation of carbonaceous deposits. Fortunately, catalyst regeneration by means of O2 pulsing was successful. Other reaction routes yielding acidic acid, ethyl acetate, or diethyl ether could be experimentally excluded.