A new separation method for phenolic compounds from low-temperature coal tar with urea by complex formation

• A new reaction agent (urea) was developed to separate the phenolic compounds from oils by complexation.
• This new separation process with high efficiency avoids the use of strongly alkaline and acidic aqueous solutions.
• The complex formation and the separation mechanism were explored by FT-IR.
• Urea exhibited good recycling property.

A new reaction agent (urea) was used to efficiently separate the phenol and cresols from low-temperature coal tar (model oil) through complexing. The effects of contact time, reaction temperature, and initial concentration were investigated. The phenols content of the upper layer was analyzed by using gas chromatography. The separation mechanism was determined by analyzing the chemical bond of the complex for urea and m-cresol using Fourier transform infrared spectrometer. Finally, urea can be recovered through reaction with diethyl ether, and the phenols removal efficiencies can remain constant after three cycles.