SEPARATION METHOD AND METHOD FOR PRODUCING ISOCYANATE

摘要

The purpose of the present invention is to provide: a method for separation of a mixture that contains a plurality of compounds that reversibly react with each other, in particular a method for efficiently separating an isocyanate from a mixture that contains the isocyanate and a hydroxy compound, and especially, a method for efficiently separating an isocyanate and a hydroxy compound from each other, said isocyanate and hydroxy compound being produced by thermal decomposition of an N-substituted carbamic acid ester. The objective is achieved by a method for separating a mixture that contains an active hydrogen-containing compound (A) and a compound (B) that reversibly reacts with the active hydrogen-containing compound using a multi-stage distillation column, wherein the active hydrogen-containing compound (A) and the compound (B) are separated by distillation using a multi-stage distillation column in the presence of an inactive intermediate-boiling-point compound (C) that has a normal boiling point between the normal boiling point of the active hydrogen-containing compound (A) and the normal boiling point of the compound (B) and is chemically inactive with respect to both of the compound (A) and the compound (B).