Perfluoro(butylcyclohexane)–<i>Cis</i>‐Perfluorodecalin Mixture Separation by Heteroazeotropic Distillation

Abstract This work investigates the process of distillation purification of perfluoro(butylcyclohexane) (BCH) and concentration of perfluorodecalin (PFD) from industrial samples of BCH–PFD mixtures. According to experimental data, the main difficulty is the separation of BCH from the cis ‐isomer of PFD, for which distillation is ineffective. To intensify this process, a heteroazeotropic distillation method in the presence of water was proposed and implemented on a pilot‐scale distillation column. This approach allows BCH to be purified from PFD up to more than 0.99 mol.fr. The advantage of the proposed method is the use of a safe separating agent—water, which is especially important due to the widespread use of BCH and PFD in medicine. Based on experimental data, the work also determined the characteristics of heteroazeotropes in the systems BCH–water, cis ‐PFD–water, and trans ‐PFD–water and relative volatility between BCH and cis ‐PFD in the presence of water.