Screening Monoethanolamine As Solvent to Extract Phenols from Alkane

Abstract

Coal tar is a byproduct of low temperature coal carbonization. The separation of the compounds has great significance since its main component is the mixture of phenols and hydrocarbons. In this paper, the separation of specific phenolic compounds from model coal tar (phenols + hexane) was studied. The solvent was screened by empirical analysis, the universal quasichemical functional group activity coefficient (UNIFAC), and conductor-like screening model COSMO-SAC (segment activity coefficient). COSMO-SAC was used to calculate the capacity, selectivity, and performance index of solvents. Finally, the monoethanolamine (MEA) was selected as the solvent to extract the phenols. The liquid–liquid equilibrium for the ternary mixture of phenols + hexane + MEA was measured at 303.15 K and 323.15 K under atmospheric pressure, and the results showed that MEA provided a high distribution coefficient, efficiency, and selectivity for phenols. Meanwhile, the extraction process of phenols was simulated based on the nonrandom two-liquid (NRTL) model, for which binary interaction parameters were obtained through calculations of phase equilibrium. The results showed that the purity of phenols can achieve more than 99.5 wt % using MEA as a solvent.