Mengfan Yin, Jiaxin Cui, Han Liu, Rui Zhang, Tao Zheng, Haiyan Liu, Zhichang Liu, Chunming Xu, Xianghai Meng
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引用次数: 0
Abstract
Selective separation of aromatics and alkanes is of great significance for molecular refining and meeting the consumption gap of aromatics. Liquid-liquid extraction (LLE) stands out for its favorable operating conditions and low energy demand among various separation methods. Extraction solvent is the key of LLE process. In this research, ionic liquids (ILs) were used as solvents for the separation of aromatics and alkanes, and the effect of anions and cations of ILs was explored using the distribution coefficient (Daromatics), extraction selectivity (Saromatics) and extraction performance index (PI) as evaluation indexes. The separation effect of single metal IL [Emim]Cl-1.0AlCl3 was significantly better than that of organic solvent sulfolane, and its Do-xylene, So-xylene and PI were 0.35, 51 and 18, respectively. To further improve the separation effect, the transition metal salt was added to synthesize bimetallic ILs, the content of transition metal salt was increased, the extraction effect was improved. [Emim]Cl-2.0AlCl3-0.65AgCl was selected, and its Do-xylene, So-xylene and PI were 1.01, 81 and 82, respectively. The extraction conditions were optimized, with temperature of 20 °C and the mass ratio of solvent to oil (S/O ratio) of 4. Under these conditions, Do-xylene, So-xylene and PI of [Emim]Cl-2.0AlCl3-0.65AgCl could reach 1.74, 313 and 545, respectively. [Emim]Cl-2.0AlCl3-0.65AgCl could be recovered by vacuum distillation and exhibited excellent separation performance after reusing 6 times. The separation mechanism of aromatics by different solvents was explored by quantum chemistry simulation. For [Emim][AlCl4], imidazole cation [Emim]+ exhibited a stronger interaction with o-xylene and played a leading role in the selective separation of aromatics. For [Emim][AgAlCl5], there was π-complexation between bimetallic anions and o-xylene, and the anions and cations cooperated to promote the separation of aromatics and alkanes.
期刊介绍：
Separation and Purification Technology is a premier journal committed to sharing innovative methods for separation and purification in chemical and environmental engineering, encompassing both homogeneous solutions and heterogeneous mixtures. Our scope includes the separation and/or purification of liquids, vapors, and gases, as well as carbon capture and separation techniques. However, it's important to note that methods solely intended for analytical purposes are not within the scope of the journal. Additionally, disciplines such as soil science, polymer science, and metallurgy fall outside the purview of Separation and Purification Technology. Join us in advancing the field of separation and purification methods for sustainable solutions in chemical and environmental engineering.
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