Separation of the Cresol Isomers by a New Technique Combining Distillation and Crystallization
- Type: Conference Presentation
- Conference Type:
AIChE Spring Meeting and Global Congress on Process Safety
- Presentation Date:
April 4, 2012
- Skill Level:
A new separation technology, called stripping crystallization (SC) or distillative freezing (DF), has been recently developed in our laboratory to separate the mixtures with close boiling temperatures, including the mixed xylenes [1-3] and the benzene/cyclohexane mixture . In principle, SC is operated at a triple-point condition, in which the liquid mixture is simultaneously vaporized and crystallized due to the three-phase equilibrium. Thus, SC combines distillation and crystallization to produce pure crystals. Due to the close boiling points of p-cresol (201.98°C) and m-cresol (202.27°C), it is very difficult to separate them by conventional distillation. The experiments show that the SC operation can be applied to purify p-cresol from the cresol isomer while it is rather difficult to purify m-cresol. In the purification of p-cresol by SC, the recovery rate increases with increasing operating pressure while the final purity of the product decreases with increasing operating pressure.
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