COSMO-RS based predictions for the extraction of lignin from lignocellulosic biomass using ionic liquids: Effect of cation and anion combination

摘要

A total of 34 cations belonging to 6 classes and 34 anions resulting in 1156 possible combinations are screened using the quantum chemical based COSMO-RS (COnductorlike Screening MOdel for Real Solvents) model. The Hildebrand solubility parameter (δH) is calculated using the predicted infinite dilution activity coefficient (γ~∞) of lignin in ionic liquids at 303.15 K. Initial benchmarking is performed by predicting the Hildebrand solubility parameter of lignin in ionic liquids. Comparison with literature values involving 12 ILs gives the average root mean square deviation (RMS) as 10.15 %. Except for anions based on hexafluorophosphate [PF6], bis(oxalato(2)borate) [BOB], tetracyanoborate [B(CN)4] and bis(trifluoromethylsulfonyl)amide [BTA], all the cation-anion combinations have calculated solubility parameters equal to that of lignin at 303.15 K, indicating high solubilities for lignin.