A process for recovering crude 1,3-butadiene from a C.sub.4 fraction by
extractive distillation using a selective solvent in a dividing wall
column (TK) in which a dividing wall (T) is arranged in the longitudinal
direction of the column to form a first subregion (A), a second subregion
(B) and a lower common column region (C) and which is preceded by an
extractive scrubbing column (K) is proposed.