Extraction of Phenolics from Coal By Deep Eutectic Solvents

Deep eutectic solvents (DES) are some combination of components that result in a solution with a lower melting point than the individual compounds. DES’s have been looked at recently as a tool to make processes more “green�. One such example is the extraction of sulfur containing compounds in fuel to decrease the amount of sulfur containing gases produced from combustion [1]. DES’s have shown promise in their capacity to better dissolve organic compounds than other solvents such as methanol or water [2]. Coal is a material that can benefit from the use of DES’s. Traditional solvents have already been researched in an attempt to dissolve select compounds form coal [3]. DES’s, which have shown to be effective solvents for a wide variety of organic compounds, can be used with coal to extract select compounds, or a set of compounds with similar characteristics.
 DES’s have already been used to extract phenolic compounds from olive oil [4].One potential use of this particular DES is the solvation of phenolic substances from coal. Several different DES’s were examined and tested qualitatively to see if they were able to extract phenolic compounds from coal. GCMS was used to identify extracted species. It was found that of the examined compounds ethanolamine hydrochloride and ethylenediamine showed the most promise. Various ratios of ethanolamine hydrochloride and ethylenediamine where then used to extract phenolic chemicals from Clarion 4a coal dust that had particle sizes of 35-75 micron. GCMS grade hexane was then used to extract the compounds of interest from the DES to identify. Qualitative GCMS was performed to evaluate species extracted, and quantitative mass balances were used to determine the effect of DES ratios.