Anthracene separation from analogous polycyclic aromatic hydrocarbons using the naphthalene-based solvents

Tricyclic aromatic hydrocarbons are difficult to be separated due to similar characteristics and boiling points, particularly anthracene and its isomer phenanthrene. The structural properties of anthracene and phenanthrene have been analyzed to identify the structural distinctions serving as critical factors to select a suitable solvent. Naphthalene-based solvents with electron-withdrawing substituent have been used to recognize phenanthrene molecules via electrostatic interaction. The separation performances of naphthalene-based solvents have been compared by the partition coefficient, purity, and yield, emphasizing the superior performance of acetylnaphthalene. The separation of anthracene is effective with a higher purity of 99.3 wt% and yield of 70.2 wt%, at room temperature and lower viscosity, economic cost savings of more than ten times, and beneficial by using the environment-benign back extractant. It also shows a better separation effect on real coal tar. In addition, the nonbonded interaction energy was further decomposed to illustrate the separation mechanism of naphthalene-based solvents from the energy perspective because the electrostatic interaction between phenanthrene and acetylnaphthalene plays a vital role. This work not only provides a new perspective on the selection of extractants but also promotes the application of intermolecular interaction in the separation and purification technology of analogous polycyclic aromatic hydrocarbons.