Chemical Engineering Research & Design, Vol.129, 197-208, 2018
Conceptual design for the extractive distillation of cyclopentane and neohexane using a mixture of N,N-dimethyl formamide and ionic liquid as the solvent
A conceptual design of extractive distillation for the separation of cyclopentane and neohexane mixtures using a mixture of N,N-dimethyl formamide (DMF) and ionic liquid (IL) as entrainer is developed. [PCNMIM][ClO4] was found to be the most promising solvent through the COSMO-RS calculations. Quantum chemistry calculations were then carried out to further understand the separation ability of the solvent. The vapor-liquid equilibrium (VLE) experimental results showed that the relative volatility of neohexane to cyclopentane is enhanced using the N,N-dimethyl formamide (DMF) [PCNMIMj[ClO4] mixed solvents when compared to the benchmark solvent DMF. The interaction parameters of non-random two-liquid (NRTL) model were correlated using the measured experimental VLE data. For comparison, two extractive distillation processes, using mixed solvents and pure DMF, were simulated in Aspen Plus. The results showed that the mixed solvents exhibit a better separation performance than DMF. The process using mixed solvents can reduce the total annual cost by 21.49% compared with that using DMF. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.