Effective Chemical Fixation of CO2 into Phenol Using Conventional Gas‐Solid and Novel Suspension‐Based Kolbe‐Schmitt Reactions
Year: 2025
Type: article
Abstract: The Kolbe‐Schmitt reaction is a classic route for CO2 utilisation through organic synthesis of industrially relevant chemicals. Despite the reaction's long‐standing history, detailed product separation and analysis remain underexplored, which inherently limits an accurate mechanism elucidation. This study introduces a new comprehensive approach for isolating and characterising reaction products using high‐performance liquid chromatography (HPLC) and proton nuclear magnetic resonance (1H‐NMR). Comparative experiments at 225 °C and 30 bar CO₂ were carried out using the conventional gas‐solid and novel suspension‐based methods with varying reaction times. A new two‐step reaction mechanism is proposed. In the first step, 2‐disodium salicylate and phenol are formed. In the second step, 2‐monosodium salicylate is formed, with subsequent regeneration of sodium phenoxide. This mechanism was validated by adding pure (free) phenol to the reaction media in both conventional and suspension‐based methods. The presence of added phenol was found to increase the yield of salicylic acid by 25.0 % and 8.5 % after 2 hours of reaction, for each method, respectively, compared to experiments without added phenol. Successful application of these enhanced carboxylation methods to other biomass‐derived single‐ring phenolic compounds will offer new routes for potential large‐scale CO₂ utilisation.
Source: ChemSusChem
Institution: Aston University
Language: English
Subfield: Process Chemistry and Technology
Field: Chemical Engineering
Domain: Physical Sciences
SDG: Climate action
Open Access status: hybrid
Estimated APC paid: $4,550
OpenAlex ID: W4408081188