METHOD OF SEPARATING HIGH-PURITY PERFLUORO(BUTYLCYCLOHEXANE) BY HETEROAZEOTROPIC RECTIFICATION Russian patent published in 2024 - IPC C07C23/10 B01D3/36 

FIELD: organic chemistry.

SUBSTANCE: invention relates to organic chemistry and specifically to a method of extracting high-purity perfluoro(butylcyclohexane) from industrial mixtures of fluorinated cycloalkanes with 10 carbon atoms. Disclosed is a method of separating perfluoro(butylcyclohexane) from a mixture of perfluoro(butylcyclohexane) and perfluorodecalin by heteroazeotropic rectification in the presence of water. Process is carried out in a periodic mode on a packed rectification column. Initial mixture and water are loaded into the still of the column in mass ratio of 6:1 to 7:1, after which the heating of the still of the column is started and the column is brought into the operating mode and concentration of perfluorodecalin is carried out in the distillate in the mode of infinite reflux. Then distillate fractions are withdrawn in volume not exceeding dephlegmator retention volume at specified time intervals, which are determined by time of column entering into stationary mode, until mass of still residue with target fraction of perfluoro(butylcyclohexane) reaches value calculated by formula:

where m_st is mass of stillage residue, m_in is the weight of the initial mixture of perfluoro(butylcyclohexane) and perfluorodecalin, is the weight fraction of perfluoro(butylcyclohexane) in the initial mixture, is the weight fraction of perfluorodecalin in the initial mixture, is the weight fraction of perfluoro(butylcyclohexane) in the still residue, is the weight fraction of perfluorodecalin in the still residue, n is the number of separation stages in the column, and

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EFFECT: disclosed invention enables to extract high-purity perfluoro(butylcyclohexane) (not less than 99 wt.%) from a mixture of near-boiling fluorinated cycloalkanes with 10 carbon atoms – PFBCH and PFD.

3 cl, 4 ex