Enhanced Extraction of Phenol from Model Oils Using Ionic Liquids Elucidated with Neutron Diffraction

• Main Authors: Turner, Adam H, Byrne, Emily L, Pereira, Thaise, Holbrey, John D
• Format: text
• Published: Archīum Ateneo 2020
• Subjects: Ionic Liquids; Extraction; Sustainable; Green; Liquid Structure; Neutron Diffraction; SANS; EPSR; Chemistry; Materials Chemistry
• Online Access: https://archium.ateneo.edu/chemistry-faculty-pubs/161; https://pubs.rsc.org/en/content/articlelanding/2020/cp/d0cp01013h
• Institution: Ateneo De Manila University

Aromatic cation ionic liquids (ILs) based on alkylpyridiniums are shown to be good phenol extractants from model oils (hexane/toluene). ILs with hard basic anions are found to have best extraction efficiency consistent with tetraalkylammonium salts ([NR4]X). Key extraction interactions were analysed using small angle neutron diffraction. Trifluoromethanesulfonate ([OTf]- or triflate) anions provide the synergistic effects of reduced cation-phenol centre of mass (COM) distances and increased hydrogen bonding that are linked to the improved extraction efficiency of these hard basic anions. Increases in cation electron density (methyl-pyridinium ([Me-Py]+) vs methyl-picolinium ([Me-3-Pic]+)) also reduce cation-phenol COM interaction lengths consistent with small increases in extraction efficiency for the same ionic liquids.