The pretreatment or disruption of a cellulose I \(\beta \) crystallite by four deep eutectic solvents (DES): choline-chloride ethylene glycol, choline-chloride oxalic acid, choline-chloride urea, and choline-chloride levulinic acid, was described from the atomistic interactions observed in molecular dynamics and ab-initio (NCI-AIM) studies. The cellulose I \(\beta \) disruption was studied considering plausible correlations between the Kamlet-Taft (α and β) solvent parameters, and a series of thermodynamic, structural, and energetic properties. It was found that the Kamlet-Taft parameters correlated with the thermodynamic properties of the DES, as well as their variations after the addition of the cellulose crystallite. Structural analysis revealed that the weaker the interactions within the molecules of the solvent, the stronger the interactions between the hydroxyl group from cellulose with the chloride anion and with the hydrogen bond donor. Further analysis indicated that the \(R-CO-R\) moieties in the hydrogen bond donor within the solvent, displayed best interplaying with the cellulose. The hydrogen bond occupancies within the cellulose crystallite, evidenced that the main \(O6-H6\cdots O2/O3\) and \(O2-H2\cdots O6\) interchain hydrogen bonds in the glucan located at the edge of the solute, were replaced by weak \(O6-H6\cdots O4\) hydrogen bonds in all solvents. This effect was related to the \({O/Cl}_{DES}\cdots H-donor\) and \({O}_{DES}-{H}_{DES}\cdots acceptor\) HBs between cellulose and DES molecules, and it was confirmed by the non-covalent interactions obtained through DFT calculations. The energetic interactions and the atomistic degree of disruption of the cellulose crystallite, were not completely described by the Kamlet-Taft β or α parameters when considered separately. Surprisingly, by using the net basicity (\(\beta -\alpha \)) definition such correlations were improved, suggesting that both parameters must be considered together to develop new, green, and sustainable solvents for cellulose pretreatment process.

Graphic abstract

中文翻译：

---

基于氯化胆碱的低共熔溶剂在室温下对纤维素预处理的见解：原子研究

描述了通过四种低共熔溶剂 (DES)预处理或破坏纤维素 I \(\beta \)微晶：氯化胆碱乙二醇、氯化胆碱草酸、氯化胆碱尿素和氯化胆碱乙酰丙酸从分子动力学和从头算（NCI-AIM）研究中观察到的原子相互作用。考虑到 Kamlet-Taft ( α和β之间的似是而非的相关性，研究了纤维素 I \(\beta \)破坏) 溶剂参数，以及一系列热力学、结构和能量特性。结果发现，Kamlet-Taft 参数与 DES 的热力学性质以及它们在添加纤维素微晶后的变化相关。结构分析表明，溶剂分子内的相互作用越弱，纤维素中的羟基与氯阴离子和氢键供体的相互作用越强。进一步的分析表明溶剂中氢键供体中的\(R-CO-R\)部分与纤维素的相互作用最好。纤维素微晶内的氢键占据，证明主要的\(O6-H6\cdots O2/O3\)和\(O2-H2\cdots O6\)位于溶质边缘的葡聚糖中的链间氢键在所有溶剂中都被弱的\(O6-H6\cdots O4\)氢键所取代。这种效应与纤维素之间的\({O/Cl}_{DES}\cdots H-donor\)和\({O}_{DES}-{H}_{DES}\cdots acceptor\) HBs 有关和 DES 分子，并通过 DFT 计算获得的非共价相互作用证实了这一点。当单独考虑时，Kamlet-Taft β 或 α 参数没有完全描述纤维素微晶的能量相互作用和原子破坏程度。令人惊讶的是，通过使用净碱度 ( \(\beta -\alpha \)) 定义这种相关性得到了改进，这表明必须同时考虑这两个参数，以开发用于纤维素预处理过程的新的、绿色的和可持续的溶剂。

图形摘要