{"title":"使用混合溶剂从庚烷中分离噻吩的液液平衡数据和机理","authors":"Chong Yang*, Shimin Xu, Yuyao Xie, Yepeng Xiao, Lihua Cheng and Xinping Ouyang, ","doi":"10.1021/acs.jced.4c00154","DOIUrl":null,"url":null,"abstract":"<p >Solvent extraction is a promising method for removing organic sulfides from fuel oils in refineries. However, selecting an appropriate extractant requires a fundamental understanding of liquid–liquid equilibria. In this study, we collected liquid–liquid equilibrium (LLE) data for ternary heptane + thiophene + solvent systems at 298.2 K and 101.3 kPa. The extraction capabilities of the selected solvents (ethylene glycol (EG), <i>N</i>-formylmorpholine, 1,3-propanediol, 1,4-butanediol, 1,2-propanediol, <i>N</i>-methyl-2-pyrrolidone (NMP), <i>N</i>,<i>N</i>-dimethylacetamide, and benzyl alcohol) for separating heptane and thiophene were assessed based on the distribution constant (<i>D</i>) and separation factor (<i>S</i>). NMP exhibited the highest <i>D</i> value, whereas EG exhibited the lowest. In contrast, the EG had the highest <i>S</i> value. Therefore, to balance <i>D</i> and <i>S</i> simultaneously, mixtures of EG and NMP at different molar ratios were used as extractants. Molecular-level investigation into the separation mechanism was conducted via molecular dynamics simulations and density functional theory calculations. The enhanced <i>S</i> value of EG was attributed to a significant difference in its interaction energies with thiophene and heptane, whereas the enhanced <i>D</i> value of NMP resulted from a more negative solvation-free energy upon binding thiophene. Finally, a comparison of the thermodynamic models showed that the nonrandom two-liquid (NRTL) model and the universal quasichemical (UNIQUAC) model were equally suitable for correlating the experimental data for the ternary and quaternary heptane + thiophene + solvent systems; the root-mean-square deviation (RMSD) values for the NRTL model were all <1%, whereas the maximum RMSD value for the UNIQUAC model was 1.57%. The obtained liquid–liquid equilibrium data and mechanistic insights can aid in improving extractive desulfurization using conventional organic solvents toward the efficient, low-cost, and simple production of clean fuel oils with ultralow sulfur contents.</p>","PeriodicalId":42,"journal":{"name":"Journal of Chemical & Engineering Data","volume":null,"pages":null},"PeriodicalIF":2.0000,"publicationDate":"2024-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Liquid–Liquid Equilibrium Data and Mechanism for Separating Thiophene from Heptane Using Mixed Solvents\",\"authors\":\"Chong Yang*, Shimin Xu, Yuyao Xie, Yepeng Xiao, Lihua Cheng and Xinping Ouyang, \",\"doi\":\"10.1021/acs.jced.4c00154\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p >Solvent extraction is a promising method for removing organic sulfides from fuel oils in refineries. However, selecting an appropriate extractant requires a fundamental understanding of liquid–liquid equilibria. In this study, we collected liquid–liquid equilibrium (LLE) data for ternary heptane + thiophene + solvent systems at 298.2 K and 101.3 kPa. The extraction capabilities of the selected solvents (ethylene glycol (EG), <i>N</i>-formylmorpholine, 1,3-propanediol, 1,4-butanediol, 1,2-propanediol, <i>N</i>-methyl-2-pyrrolidone (NMP), <i>N</i>,<i>N</i>-dimethylacetamide, and benzyl alcohol) for separating heptane and thiophene were assessed based on the distribution constant (<i>D</i>) and separation factor (<i>S</i>). NMP exhibited the highest <i>D</i> value, whereas EG exhibited the lowest. In contrast, the EG had the highest <i>S</i> value. Therefore, to balance <i>D</i> and <i>S</i> simultaneously, mixtures of EG and NMP at different molar ratios were used as extractants. Molecular-level investigation into the separation mechanism was conducted via molecular dynamics simulations and density functional theory calculations. The enhanced <i>S</i> value of EG was attributed to a significant difference in its interaction energies with thiophene and heptane, whereas the enhanced <i>D</i> value of NMP resulted from a more negative solvation-free energy upon binding thiophene. Finally, a comparison of the thermodynamic models showed that the nonrandom two-liquid (NRTL) model and the universal quasichemical (UNIQUAC) model were equally suitable for correlating the experimental data for the ternary and quaternary heptane + thiophene + solvent systems; the root-mean-square deviation (RMSD) values for the NRTL model were all <1%, whereas the maximum RMSD value for the UNIQUAC model was 1.57%. The obtained liquid–liquid equilibrium data and mechanistic insights can aid in improving extractive desulfurization using conventional organic solvents toward the efficient, low-cost, and simple production of clean fuel oils with ultralow sulfur contents.</p>\",\"PeriodicalId\":42,\"journal\":{\"name\":\"Journal of Chemical & Engineering Data\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":2.0000,\"publicationDate\":\"2024-05-31\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Chemical & Engineering Data\",\"FirstCategoryId\":\"1\",\"ListUrlMain\":\"https://pubs.acs.org/doi/10.1021/acs.jced.4c00154\",\"RegionNum\":3,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"CHEMISTRY, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Chemical & Engineering Data","FirstCategoryId":"1","ListUrlMain":"https://pubs.acs.org/doi/10.1021/acs.jced.4c00154","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
摘要
溶剂萃取是一种去除炼油厂燃料油中有机硫化物的有效方法。然而,选择合适的萃取剂需要对液液平衡有基本的了解。在这项研究中,我们收集了在 298.2 K 和 101.3 kPa 下庚烷 + 噻吩 + 溶剂三元体系的液液平衡 (LLE) 数据。所选溶剂(乙二醇(EG)、N-甲酰基吗啉、1,3-丙二醇、1,4-丁二醇、1,2-丙二醇、N-甲基-2-吡咯烷酮(NMP)、N,N-二甲基乙酰胺和苯甲醇)分离庚烷和噻吩的萃取能力根据分布常数(D)和分离因子(S)进行评估。NMP 的 D 值最高,而 EG 的 D 值最低。相反,EG 的 S 值最高。因此,为了同时平衡 D 和 S,使用了不同摩尔比的 EG 和 NMP 混合物作为萃取剂。通过分子动力学模拟和密度泛函理论计算,对分离机理进行了分子水平的研究。EG 的 S 值增强是由于其与噻吩和庚烷的相互作用能存在显著差异,而 NMP 的 D 值增强则是由于其与噻吩结合时的无溶解能为负值。最后,对热力学模型的比较表明,非随机双液(NRTL)模型和通用准化学(UNIQUAC)模型同样适用于关联三元和四元庚烷+噻吩+溶剂体系的实验数据;NRTL 模型的均方根偏差(RMSD)值均为 1%,而 UNIQUAC 模型的最大均方根偏差值为 1.57%。所获得的液液平衡数据和机理见解有助于改进使用传统有机溶剂的萃取脱硫工艺,从而高效、低成本、简单地生产出硫含量超低的清洁燃料油。
Liquid–Liquid Equilibrium Data and Mechanism for Separating Thiophene from Heptane Using Mixed Solvents
Solvent extraction is a promising method for removing organic sulfides from fuel oils in refineries. However, selecting an appropriate extractant requires a fundamental understanding of liquid–liquid equilibria. In this study, we collected liquid–liquid equilibrium (LLE) data for ternary heptane + thiophene + solvent systems at 298.2 K and 101.3 kPa. The extraction capabilities of the selected solvents (ethylene glycol (EG), N-formylmorpholine, 1,3-propanediol, 1,4-butanediol, 1,2-propanediol, N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide, and benzyl alcohol) for separating heptane and thiophene were assessed based on the distribution constant (D) and separation factor (S). NMP exhibited the highest D value, whereas EG exhibited the lowest. In contrast, the EG had the highest S value. Therefore, to balance D and S simultaneously, mixtures of EG and NMP at different molar ratios were used as extractants. Molecular-level investigation into the separation mechanism was conducted via molecular dynamics simulations and density functional theory calculations. The enhanced S value of EG was attributed to a significant difference in its interaction energies with thiophene and heptane, whereas the enhanced D value of NMP resulted from a more negative solvation-free energy upon binding thiophene. Finally, a comparison of the thermodynamic models showed that the nonrandom two-liquid (NRTL) model and the universal quasichemical (UNIQUAC) model were equally suitable for correlating the experimental data for the ternary and quaternary heptane + thiophene + solvent systems; the root-mean-square deviation (RMSD) values for the NRTL model were all <1%, whereas the maximum RMSD value for the UNIQUAC model was 1.57%. The obtained liquid–liquid equilibrium data and mechanistic insights can aid in improving extractive desulfurization using conventional organic solvents toward the efficient, low-cost, and simple production of clean fuel oils with ultralow sulfur contents.
期刊介绍:
The Journal of Chemical & Engineering Data is a monthly journal devoted to the publication of data obtained from both experiment and computation, which are viewed as complementary. It is the only American Chemical Society journal primarily concerned with articles containing data on the phase behavior and the physical, thermodynamic, and transport properties of well-defined materials, including complex mixtures of known compositions. While environmental and biological samples are of interest, their compositions must be known and reproducible. As a result, adsorption on natural product materials does not generally fit within the scope of Journal of Chemical & Engineering Data.