Purification of p-Cresol, o-Cresol, m-Cresol, and 2,6-Xylenol from the Quaternary Mixture by Three-Phase Crystallization

Abstract

Three-phase crystallization (TPC) was applied in this work to purify the major component from quaternary liquid mixtures consisting of p-cresol, o-cresol, m-cresol, and 2,6-xylenol. As TPC is operated in a series of three-phase transformations by decreasing temperature and reducing pressure, TPC combines melt crystallization and vaporization to produce the major component crystalline product along with the vapor mixture from the liquid mixture. A model based on the van't Hoff equation and Raoult's law coupled with mass and energy balances was proposed to determine a series of three-phase transformation conditions, which were adopted to direct the batch TPC experiments. The experimental purity and recovery ratio of the final product for purification of pcresol, o-cresol, m-cresol, or 2,6-xylenol were compared with the calculated results predicted by the model. The order of difficulty for purification among p-cresol, o-cresol, m-cresol, and 2,6-xylenol was examined.

Research Progress on Extraction, Separation, and Purification Methods of Plant Essential Oils

“…Combining the MC method and vaporization, Shiau LD and his colleagues developed a new separation and purification technology called TPC for the separation of the mixtures with close boiling temperatures [99]. By reducing temperature and pressure, it produces desired crystalline products from liquid mixtures with the unwanted components evaporated through three-phase conversion.…”

The Influence of the Solid Solution Formation on Purification of L-Menthol from the Enantiomer Mixture by Three-Phase Crystallization

“…2023, 24, 14933 2 of 17 systems. A solid solution is a solid mixture containing a minor component uniformly distributed within the crystal lattice of the major component, which has never been encountered during TPC in the previous studies [30][31][32][33][34][35][36][37][38]. However, the formation of solid solutions has been reported in melt crystallization for mixtures enriched with L-menthol or D-menthol enantiomers [39].…”

“…The unique feature of melt crystallization is that no solvent is required; however, the subsequent separation of formed crystals from melt is often a challenging task for downstream processing. Recently, Shiau and his coworkers have developed a new separation technology, three-phase crystallization (TPC), which combines melt crystallization and vaporization for the separation of the mixtures with the close boiling temperatures [30][31][32][33][34][35][36][37][38]. Basically, TPC is operated via a series of three-phase transformations occurring in a liquid mixture, resulting in the formation of a solid product and vapor.…”