Pentaerythritol Synthesis via a Solid Catalyst Route for process related CO2 reductions

Licentiatavhandling, 2024

Pentaerythritol (penta) is a platform chemical that has been produced from formaldehyde and acetaldehyde industrially through a homogeneous catalysis route. The commercial penta synthesis process has issues with the intensive separation involved due to by-product formation, which makes the process energy intensive and emits process related CO2. In comparison, a solid catalysis route can be a better alternative to avoid rigorous post synthesis separation and to make penta formation process more selective with reduced CO2 emissions.
In this work, alkaline solid catalysts Na/MOx (MOx=TiO2, SnO2, and γ-Al2O3) were tested for penta formation instead of the liquid alkaline NaOH solution. The catalysts were prepared by a conventional impregnation method. All the products obtained after the catalyst activity test were analyzed by GCMS analysis. The Na alkali metal amount was quantified with ICP analysis for both fresh and spent catalysts to check the stability of the catalyst. Moreover, the textural, and physiochemical properties of the catalyst were investigated through BET, XRD, and CO2 TPD.
All the prepared catalysts stated above were active for penta synthesis along with other by-product formation, mainly consisting of penta-derivatives and diol compounds. Moreover, Na/SnO2 showed the highest activity among all the tested catalysts with 39% selectivity for penta at 59% conversion of formaldehyde. However, it was found that 26 wt.% of the Na metal also leached out of the catalyst during the synthesis reaction. To conclude, we have shown that it is possible to synthesize penta via a heterogeneous catalysis route using Na/SnO2 as a catalyst. Due to leaching and selectivity issues, further catalyst development is needed.