Department of Chemistry and Chemical Technology, Al-Farabi Kazakh National University, Almaty, 050000, Kazakhstan.
Institute of Physics and Technology, Satpayev University, 050013, Almaty, Kazakhstan.
J Mol Model. 2023 Jan 26;29(2):54. doi: 10.1007/s00894-023-05453-3.
The main challenge of large-scale biofuel production is related to the extraction of its undesired impurities including glycerol, water, methanol, soap/catalyst, free fatty acids, glycerides, and others. There are many ways to remove glycerol, and herein, the one alternative is the extraction of glycerol from biodiesel by deep eutectic solvents. In this regard, the mixture of a choline chloride (ChCl) and urea, methyltriphenylphosphonium chloride (MTPPCl), and ethylene glycol (EGL), as a deep eutectic solvent (DES), is effective in removing glycerol from biofuel.
In this work, we have investigated the formation mechanism of ChCl and urea, and then MTPPCl and EGL, as a DES, and then extraction of glycerol from biofuel via DES implementing density functional theory (DFT) by Gaussian09 software, B3LYP basis set, and classical all-atom molecular dynamics (MD) simulations by Gromacs software, GROMOS force field. DFT approximation demonstrates that Cl ion plays an important binding role in the formation of complexes ChCl/urea-based DES + biofuel and in MTPPCl/EGL-based DES + biofuel. We have also considered the formation and change of hydrogen bonds upon the formation of these systems using the DFT method. Large HOMO-LUMO gaps in ChCl/urea-based DES + biofuel and in MTPPCl/urea-based DES + biofuel demonstrate the stability of the complexes. The results of MD work have stated that the chloride ion formed bonding with the choline/ethylene glycol EGL, while still weakly intermolecular interacting with the urea/methyltriphenylphosphonium in ChCl/urea- and MTPPCl/EGL-based DESs. Further results of MD simulations stated that the DESs had a higher intermolecular interaction with glycerol in comparison with biofuel, thereby favoring the extraction process of glycerol from model biofuel.
• Intermolecular interactions of choline chloride and urea, methyl triphenyl phosphonium chloride, and ethylene glycol-based DESs and their applications in the extraction of glycerol from biofuel studied by DFT calculations and classical all-atom molecular dynamics simulations. • Calculated outputs of DFT calculations and classical all-atom molecular dynamics simulations for DESs and their applications in the extraction of glycerol from biofuel were discussed in detail. • The molecular formation mechanism of choline and methyl triphenyl phosphonium-based DESs and their application in the extraction process of glycerol from biofuel were summarized.
大规模生物燃料生产的主要挑战与提取其不需要的杂质有关，包括甘油、水、甲醇、肥皂/催化剂、游离脂肪酸、甘油酯等。有许多方法可以去除甘油，在此，一种替代方法是用深共晶溶剂从生物柴油中提取甘油。在这方面，氯化胆碱 (ChCl) 和尿素、甲基三苯基膦氯化物 (MTPPCl) 和乙二醇 (EGL) 的混合物作为深共晶溶剂 (DES) 可有效去除生物燃料中的甘油。
在这项工作中，我们研究了 ChCl 和尿素、然后 MTPPCl 和 EGL 形成深共晶溶剂 (DES) 的机制，然后通过 Gaussian09 软件的密度泛函理论 (DFT)、B3LYP 基组和 Gromacs 软件的经典全原子分子动力学 (MD) 模拟，从生物燃料中提取甘油，采用 GROMOS 力场。DFT 逼近表明，Cl 离子在 ChCl/尿素基 DES+生物燃料和 MTPPCl/EGL 基 DES+生物燃料复合物的形成中起着重要的结合作用。我们还使用 DFT 方法考虑了这些系统形成时氢键的形成和变化。ChCl/尿素基 DES+生物燃料和 MTPPCl/尿素基 DES+生物燃料中较大的 HOMO-LUMO 间隙表明复合物的稳定性。MD 工作的结果表明，氯化物离子与胆碱/乙二醇 EGL 形成键合，而在 ChCl/尿素和 MTPPCl/EGL 基 DES 中仍与尿素/三苯基膦弱分子间相互作用。进一步的 MD 模拟结果表明，DES 与甘油的分子间相互作用高于与生物燃料的相互作用，从而有利于从模型生物燃料中提取甘油。
• 通过密度泛函理论计算和经典全原子分子动力学模拟研究了氯化胆碱和尿素、甲基三苯基膦氯化物和乙二醇基 DES 之间的分子间相互作用及其在从生物燃料中提取甘油中的应用。• 详细讨论了 DES 及其在从生物燃料中提取甘油中的应用的密度泛函理论计算和经典全原子分子动力学模拟的计算结果。• 总结了胆碱和甲基三苯基膦基 DES 的分子形成机制及其在从生物燃料中提取甘油的提取过程中的应用。
