Patent ID: 7692053

Claim:
A process for obtaining crude 1,3-butadiene comprising: extractively distilling with a selective solvent the crude 1,3-butadiene in a dividing wall column from a C 4 cut comprising C 4 acetylenes as secondary components; controlling the energy input into the dividing wall column to obtain a bottom stream comprising solvent, C 4 acetylenes and an economically acceptable proportion of 1,3-butadiene which is drawn off from the dividing wall column; feeding the bottom stream to an acetylenes outgasser; wherein the C 4 acetylenes are stripped out overhead and purified solvent is obtained as a bottom stream; wherein the dividing wall column comprises a bottom evaporator, a dividing wall is disposed in the longitudinal direction of the dividing wall column to form a first subregion, a second subregion and a lower combined column region having one or more separation stages, and the dividing wall column is disposed upstream of an extractive wash column.