The catalytic transformation of furfural to cyclopentanone has been investigated using two different liquid phases as solvent: water and 30 wt.% tert–butanol in water. When using neat water at 160 °C, 40 bar of H₂, and after 2 h of reaction time, furfural polymerizes, and the yield of cyclopentanone is just 42% with a low carbon balance, indicating that furfural is transformed to non-detected by-products, likely heavy resins. When using 30 wt.% tert–butanol in water, the yield of cyclopentanone is ca. 20%, and the major product is furfuryl alcohol with a 47% yield. We have studied the catalytic transformation of the most relevant reaction intermediates in the overall conversion of furfural to cyclopentanone. In the presence of tert–butanol, two steps are inhibited in the overall pathway: (i) the Piancatelli rearrangement of furfuryl alcohol and (ii) the transformation of cyclopentenone. This inhibition is attributed to the neutralization of protons from water dissociation by surface sites on the catalyst, preventing their participation in the overall reaction. To counteract these inhibitions when tert–butanol is present, higher H₂ pressure (60 bar) and temperatures (200 °C) are required. We have been able to obtain productivities per gram of catalyst and mols of Cu basis of 411 g_prod·h⁻¹·g_cat⁻¹ and 14 g_prod·s⁻¹·mol_Cu⁻¹, respectively, which is substantially above that found for other copper-based catalysts.

The synthesis of dimethyl adipate (DAP), a stable configuration of adipic acid, from biomass-derived cyclopentanone (CPO) and dimethyl carbonate (DMC) constitutes an attractive greener route than petroleum-based industrial processes. Solid basic catalysts such as MgO, Mg₅(CO₃)₄(OH)₂·4H₂O, KOCH₃ and Ca(OCH₃)₂ have been used achieving a DAP yield up to 30% at 533 K. In addition to the type of catalyst, other operating conditions such as the substrate, reaction time, temperature and CPO concentration have been studied. The methylation of DAP and CPO and the self-aldol condensation of CPO to form dimers and oligomers are reactions that occur in parallel with the production of DAP. It has been established that the main challenge is the self-aldol condensation of CPO. It has been identified that at short reaction times, to prevent methylation, and at dilute concentrations, to avoid CPO self-condensation, the DAP formation rate is much higher than these other competitive reactions. Finally, it should be noted that a DAP productivity up to 3.45 g·gcat⁻¹·h⁻¹ has been achieved under mild conditions.

Potassium-exchanged tin-functionalized USY zeolite ([K]­Sn-USY) has been studied in the continuous transformation of glucose, xylose, and their mixtures in a fixed-bed reactor for the production of methyl lactate at 150 °C. The catalyst efficiently drives the transformation of all the studied substrates, though it faces several deactivation mechanisms, especially in the case of hexoses. Potassium leaching from the catalyst and organic deposition adduced to furanics produced during the reaction were ascribed as the major deactivation causes. The addition of small amounts (10 mg/kg) of potassium (as KCl or KOH) alleviated the catalyst deactivation, allowing the latter stable methyl lactate production over 30% yield for over 140 h from individual carbohydrates and complex sugar mixtures like Scots Pine hemicellulose hydrolysates.