Selective purification of polymer-grade succinic acid from fermentation broths using a designed type III porous liquids [diOTMG]Cl@Zr-bptc

[diOTMG]Cl@Zr-bptc porous liquid (PL) was successfully prepared. • PL enhanced succinic acid yield 8.71-fold compared to organic amine. • 99.98% pure succinic acid was obtained by PL extraction and crystallization. • Carboxylic acids are separated via affinity and molecular size differences. Global environmental deterioration and plastic pollution drive the demand for biodegradable polymers, which rely on ultrapure monomer, such as succinic acid (SA). However, current bio-SA purification suffers from low purity (94–98%) and complex multistep processes due to similar affinity of homologues. Here, we introduce a type III porous liquid (PL) composed of ionic liquid [diOTMG]Cl and metal-organic framework Zr-bptc for SA purification, achieving 99.98 ± 0.01 wt% SA purity with 84.15% yield after crystallization. This represents an 8.71-fold yield increase in yield and 6.55-fold improvement in selectivity over tri-n-octylamine. Laboratory-scale assessment confirms the PL solution as a sustainable process. Mechanistically, carboxylic acids are extracted synergistically through hydrogen bonding/anion exchange, while Grand Canonical Monte Carlo (GCMC) simulations showed selective adsorption of acetic acid in Zr-bptc pores. Weak interactions and kinetic size sieving ensure high SA purity. This PL provides an efficient solution for producing polymer-grade monomers, addressing the long-standing challenge in fermented homologue separation. Download: Download high-res image (122KB) Download: Download full-size image