| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for separating difluoromethane from an azeotropic mixture. SOLUTION: A method for separating difluoromethane from the mixture of difluoromethane and at least one impurity comprises: a step of extractively distilling said mixture using dichloromethane as the extractive agent from a distillation column 10 to recover a product stream of difluoromethane having a concentration of said impurity lower than that of said mixture from an overhead stream 4; and a step of recycling a portion of sidestream 5 into a fluorination reactor. COPYRIGHT: (C)2007,JPO&INPIT
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