Patent ID: 8361280

Claim:
A process for distillatively obtaining pure 1,3-butadiene from crude 1,3-butadiene in a plant comprising one or more distillation columns, the process comprising supplying a feed stream of crude 1,3-butadiene to the one distillation column or a first of the plurality of distillation columns, wherein the one distillation column or the plurality of distillation columns have a flange with an internal diameter of at least 80 mm, the flange comprising two mutually opposite plane-parallel surfaces with an intermediate seal which seals an interior of the one distillation column or of the first of the plurality of distillation columns from an intermediate space on an atmosphere side between the two mutually opposite plane-parallel surfaces, and the intermediate space on the atmosphere side between the two mutually opposite plane-parallel surfaces is closed off from the atmosphere to form a chamber, wherein the chamber is purged continuously during the operation of the plant with nitrogen comprising 1% by weight of molecular oxygen or less, based on a total weight of the nitrogen.