No abstract

No abstract

The separation of short‐chain hydrocarbon mixtures is of great significance for the efficient utilization of fossil energy. Liquid–liquid extraction, as one of the commonly used treatment methods, has significant advantages in terms of operation conditions and energy consumption. As a new dipolar aprotic solvent developed in recent years, dihydrolevoglucosenone (Cyrene) has a wide range of sources and a green composition. In this paper, the liquid–liquid equilibrium and extraction mechanism of Cyrene and five hydrocarbon mixtures with short carbon chains, including toluene/n‐heptane, toluene/cyclohexane, n‐hexane/cyclohexane, n‐pentane/pentene, and n‐hexane/hexene, have been studied by combining experiments and quantum chemical calculations, and the extraction effects under different conditions have been investigated. The results showed that the forces between Cyrene and the different solutes are mainly van der Waals (VDW) forces dominated by dispersion forces, with some weak hydrogen bonds present. Due to the difference in interaction energy, the order of extraction selectivity was toluene‐n‐heptane > toluene‐cyclohexane > n‐hexane‐hexene > n‐hexane‐cyclohexane > n‐pentane‐pentene, and the order of distribution coefficients of the extracted components (aromatics, olefins, and cycloalkanes) was toluene > pentene > hexene > cyclohexane. The dissolution processes of all systems were heat‐absorbing, and they all reached the extraction equilibrium within 60 s. The reliability of the experimental data was verified using the Othmer–Tobias equation and the Hand equation, and the binary interaction parameters of all systems were obtained by the non‐random two liquid (NRTL) model, providing basic data and references for the subsequent studies on the separation of Cyrene and short‐chain hydrocarbons.

The efficient and sustainable separation of aromatics from aliphatics is an ongoing challenge in chemical engineering. In this work, the protic ionic liquid N‐methylpyrrolidonium methanesulphonate ([NMP][MSA]) was used to separate toluene from n‐heptane or cyclohexane. Nuclear magnetic resonance and Fourier‐transform infrared spectroscopy were used to demonstrate the successfully synthesis of [NMP][MSA]. Density functional theory (DFT) calculations were used to confirm that the interaction of [NMP][MSA] with toluene would be stronger than those with n‐heptane and cyclohexane, with electrostatic forces and dispersion playing the primary roles and induction playing a minor role. Furthermore, independent gradient model (IGM) analysis demonstrated that van der Waals forces make a major contribution to the stability of [NMP][MSA]–toluene. For a 10 mol% toluene/n‐heptane system, the toluene distribution coefficient and selectivity were found to be 0.35 and >70, respectively, while the corresponding values were 0.40 and 27 for a 10 mol% toluene/cyclohexane system. Changing the extraction temperature seemed to have little effect on separation performance. The effects of solvent dosage, initial concentration, and extractant recycling were also investigated. Overall, our results show that [NMP][MSA] has potential for industrial use.

No abstract