Toward bio-based plasticizers: making plastics greener
Researchers from the University of Antwerp, RWTH Aachen University, and the Max Planck Institute for Chemical Energy Conversion have achieved a breakthrough in sustainable chemistry. Their study, published in Angewandte Chemie International Edition, introduces a new low-energy mechanochemical process using bio-derivable catechol and CO2 to produce renewable plasticizers for PVC (polyvinyl chloride) and PLA (poly-lactic acid), thereby offering a promising path to replace current petrochemical plasticizers.
The challenge: replacing fossil-based plasticizers
Plasticizers are the most used plastic additives worldwide, with a total market value of about €17 billion (2024). They are added to plastics such as PVC and PLA to make them more flexible and easier to process. However, the dominant plasticizers on the market today are petro-derived and have been under scrutiny due to their human and ecotoxicity issues. For instance, phthalates, a group of aromatic esters, have been associated with hormone disruption and potential carcinogenic effects.
To address climate and toxicity issues, there is a need to developing more safe and sustainable plasticizer alternatives from renewable biomass. A promising candidate is catechol, an aromatic diol with an annual production of 40k tonnes and currently largely petro-derived. Recent advances have shown that bio-based catechol can instead be produced from non-edible biomass, such as lignin in softwood, clove oil, or rice bran derivatives. However, converting catechol into building blocks for plasticizers has until now required an energy-intensive chemical reaction, known as the Kolbe-Schmitt reaction, which demands high temperatures (up to 225 °C) and CO2 pressures (up to 100 bar).
The innovation: grinding molecules instead of heating them
In a pioneering study, researchers developed a mechanochemical adaptation of the energy-intensive Kolbe-Schmitt reaction. Using ball milling, where reagents are ground by small high-speed balls, the researchers achieved the carboxylation reaction at room temperature and at just 4 bar CO2 pressure. This is the first time the Kolbe–Schmitt reaction has been carried out under such mild conditions using gaseous CO2.
The process yields a mixture of catechol-derived carboxylates in a single step, which can be converted into plasticizers without complex purification. When incorporated into PVC and PLA, these bio‑based plasticizers proved competitive with commercial petrochemical plasticizers (DEHP and DINCH). Together, the findings demonstrate that producing high‑value plasticizers from biomass is technically viable and commercially promising.
The PADDL project
This work was conducted within the Moonshot project PADDL, which aimed to develop new bio-based chemicals matching the performance of existing petroleum-based equivalents. Specifically, PADDL focused on valorizing lignin, a primary wood component, into high-value chemicals, with catechol as a key target molecule.
The publication supports Moonshot Flanders' mission to guide the Flemish industry toward climate neutrality. Substituting fossil-based molecules with bio-based alternatives offers a pathway to cut CO2 emissions, and this research proves such substitutes can rival commercial products in performance.
Read the scientific article here:
De Vos, D., Pfennig, V. S., Goddé, A., Vroemans, R., Krückel, T., Marcinkowska, N., Bartalucci, E., Wiegand, T., Bolm, C., & Maes, B. U. W. (2026). A Mechanochemical Kolbe–Schmitt Reaction: Catechol Carboxylation Provides Building Blocks for Renewable Plasticizers. Angewandte Chemie International Edition, e19827. https://doi.org/10.1002/anie.202519827