Extraction of guaiacol from hydrocarbons as an alternative for the upgraded bio-oil purification: Experimental and computational thermodynamic study

Abstract

Guaiacol is an important lignin derivative used as an intermediate for obtaining high value-added molecules through heterogeneous catalysis. Typical solvents used in the catalytic conversion of guaiacol are dodecane and hexadecane. In order to understand the potential separation of guaiacol from the conversion mixture, three compounds were selected as potential extracting solvents: methanol, ethanol, and acetone. Thus, this study is divided in three parts. First, the measurement of the properties of the pure components involved in this work as density and viscosity. Second, the measurement of the density, viscosity, and liquid-liquid equilibrium of the binary systems, and third, the measurement of the liquid-liquid equilibrium of the ternary systems composed by guaiacol + (methanol, ethanol or acetone) + (dodecane or hexane). Pure component and binary mixtures properties were obtained at temperatures between 293.15 K and 333.15 K and the ternary systems at 313.15 K, all of them at 101.13 kPa. Phase equilibrium was modeled with NRTL, COSMO-RS, and COSMO-SAC. The results obtained suggest that methanol is the best extracting solvent of guaiacol due to its high selectivity, high affinity with the solute, and a wide liquid–liquid immiscibility with dodecane. Models selected in this work represent accurately the ternary system composed by guaiacol + methanol + (dodecane or hexadecane), so they can be chosen as potential tools for further process simulation of extraction and recovery of guaiacol.