Separation of phenolic compounds from coal-based liquid oil is an important and challenging process in the coal chemical industry. Using deep eutectic solvents (DES) as an extractant can realize high phenol removal efficiency and avoid the production of phenolic effluent, but a certain amount of neutral oil is still entrained in the extraction layer. It is of great significance to elucidate the relationship between phenolic compounds removal by DES and the entrainment of neutral oil. In this work, different quaternary ammonium salt based deep eutectic solvents and different phenolic compounds content in oils were investigated to give an insight to the neutral oil entrainment behavior, assisted by the Kamlet-Taft solvatochromic method, spectrum analysis, and quantum chemical calculations. The results showed that there is a difference between the entrainment of benzene and naphthalene when using the same DES. The hydrogen bond acceptor/donor in DESs could lead to different neutral oil entrainment behavior, which provides a possibility to achieve lower neutral oil entrainment by structure design. This work revealed that the neutral oil entrainment behavior during coal-based liquid oil dephenolization by DES is strengthened by π-π interaction and the solubilization effect of phenolic compounds; a symmetric structure of the cation ion in hydrogen bond acceptor creates a special electrostatic environment that prevents neutral oil from approaching extractant particles.<br/>

Elucidating neutral oil entrainment behavior during the dephenolization of coal-based liquid oil

2019 Spring National Meeting

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