Complex Extraction of Phenol, o-Cresol and p-Cresol from Model Coal Tar Using Methanol and Acetone Solutions

Aims: The extractive performance of two solution solvents were studied for the complex extraction of phenols from model coal tar at varying conditions and variables.
Study Design: Ordinary solvent extraction can preferentially extract phenolic compounds from the other compositions in coal tar. In order to separate the phenolic compounds from coal tar, it is essential to choose an extractant that has a specific interaction with phenols but insoluble in coal tar. Toward this aim, methanol solution and acetone solution may be candidate for their following characteristic.
Place and Duration of Study: Department of Chemical Engineering, Semarang State University and Department of Chemical Engineering, Gadjah Mada University.
Methodology: For this research, the influence of temperature, mass ratio of solvent to feed, mole fraction of water in solvent and composition of solvent in the extractbillity of phenols were studied for methanol solution and acetone solution using model coal tar. Model coal tar is used in which the solute is a phenol, o-cresol, and p-cresol; diluent is kerosene, and solvent are water and methanol or acetone. Methanol and acetone need to be mixed with water because their polarities are not strong enough to form immiscible mixture with kerosene. The extract phase of the each extraction processes are analyzed by GC to obtain the concentration of each component in the extract phase and the concentration of each component in raffinate phase.
Results: Maximum of solute mole fraction (0.055 phenol; 0,037 o-cresol, and 0.061 p-cresol), maximum of the distribution coefficient (2.80 phenol; 3.66 o-cresol; and 4.55 p-cresol), and maximum of the yield (0.66 phenol; 0.64 o-cresol; and 0.76 p-cresol) obtained in the mass ratio of solvent-feed is 1, temperature is 308 K, and mole fraction of water in solvent is 0.2 by using an aqueous methanol solvent.
Conclusion: Even though the mole fractions of the solutes in the extract are relatively low, but since the boiling points of the solvents and the solutes are differ significantly, the solutes can be easily separated by evaporating the solvents.
Phenolic compounds in low temperature coal tar may be extracted efficiently by methanol and acetone solutions at ambient temperature.