The solid–liquid equilibrium (SLE) behavior and liquid–liquid extraction (LLX) abilities of deep eutectic solvents (DESs) containing (a) thymol and L-menthol, and (b) trioctylphosphine oxide (TOPO) and L-menthol were evaluated. The distribution coefficients (K_D) were determined for the solutes relevant for two biorefinery cases, including formic acid, levulinic acid, furfural, acetic acid, propionic acid, butyric acid, and L-lactic acid. Overall, for both cases, an increasing K_D was observed for both DESs for acids increasing in size and thus hydrophobicity. Furfural, being the most hydrophobic, was seen to extract the highest K_D (for DES (a) 14.2 ± 2.2 and (b) 4.1 ± 0.3), and the K_D of lactic acid was small, independent of the DESs (DES (a) 0.5 ± 0.07 and DES (b) 0.4 ± 0.05). The K_D of the acids for the TOPO and L-menthol DES were in similar ranges as for traditional TOPO-containing composite solvents, while for the thymol/L-menthol DES, in the absence of the Lewis base functionality, a smaller K_D was observed. The selectivity of formic acid and levulinic acid separation was different for the two DESs investigated because of the acid–base interaction of the phosphine group. The thymol and L-menthol DES was selective towards levulinic acid (S_ij = 9.3 +/− 0.10, and the TOPO and L-menthol DES was selective towards FA (S_ij = 2.1 +/− 0.28).

中文翻译：

---

疏水性深共晶溶剂，用于回收基于生物的化学物质：固液平衡和液液萃取

评价了含有（a）百里香酚和L-薄荷醇以及（b）三辛基氧化膦（TOPO）和L-薄荷醇的深共熔溶剂（DES）的固液平衡（SLE）行为和液液萃取（LLX）能力。 。确定与两种生物精炼厂有关的溶质的分配系数（K _D），包括甲酸，乙酰丙酸，糠醛，乙酸，丙酸，丁酸和L-乳酸。总体而言，这两种情况下，一个增钾_d观察到既DESS为氨基酸大小，从而增加疏水性。糠醛是疏水性最强的，它提取出的K _D最高（对于DES（a）14.2±2.2和（b）4.1±0.3），K _D乳酸的含量很小，与DES无关（DES（a）为0.5±0.07和DES（b）为0.4±0.05）。与传统的含TOPO的复合溶剂相比，TOPO和L-薄荷醇DES的酸K _D处于相似的范围，而对于百里香酚/ L-薄荷醇DES，在没有Lewis碱官能团的情况下，较小的K _D被观测到。对于两个被研究的DES，甲酸和乙酰丙酸分离的选择性不同，这是因为膦基的酸碱相互作用。百里酚和L-薄荷醇DES对乙酰丙酸具有选择性（S _ij = 9.3 +/- 0.10，TOPO和L-薄荷醇DES对FA具有选择性（S _ij = 2.1 +/- 0.28）。