A First-of-its-Kind Heterogeneous Catalysis Route for Pentaerythritol Synthesis: Toward reduced energy demand and CO2 emissions

Pentaerythritol (penta) is an important platform chemical traditionally produced from formaldehyde and acetaldehyde using homogeneous alkaline catalysts. The commercial process suffers from extensive downstream separation due to by-product formation, making it energy-intensive and contributing to process-related CO2 emissions. This work explores heterogeneous catalysts as an alternative to conventional liquid alkaline systems for pentaerythritol synthesis.Catalysts based on alkali and alkaline-earth metals supported on various oxides were evaluated. Among these, Mg-based catalysts supported on γ-Al₂O₃ showed particularly promising performance, combining good activity with improved stability at relatively low metal loadings. Mg-Al hydrotalcites (HTC) emerged as the most stable and selective catalysts, with a selectivity as high as 99.7%. However, post-reaction analyses revealed that formate accumulation on the catalyst surface is a major contributor to deactivation. Additional mechanistic studies provided insight into self-Cannizzaro behaviour and the surface chemistry of formaldehyde on the hydrotalcite materials.Metal oxide (MOx) catalysts without alkali metals exhibited activity towards penta formation at elevated temperatures. ZnO nanopowder and Zn-supported catalysts were especially selective for penta and its derivatives.Overall, this thesis highlights the potential and need for further exploration of Mg-based and bifunctional metal-oxides catalyst systems for more sustainable penta synthesis. It also emphasizes the importance of controlling acid-base properties and mitigate formate-induced deactivation to achieve industrial applicability.