Abstract: The invention relates to a process for recovering argon by low-temperature separation of air. Rectifying system (2, 4) exhibits at least one air separation column (4), which has a partition (5) that runs in lengthwise direction of the column, by which air separation column (4) is separated at the level of partition (5) into a first subsection and a second subsection (6, 7). A fluid (3) that contains oxygen and argon is introduced into first subsection (6). A stream (13) that contains oxygen and argon with an argon concentration of between 15% and 50% is removed in second subsection (7).

Abstract: For the preparation of an ether, e.g., tertiary amyl methyl ether, an olefin-containing feed stream is catalytically etherified with an alcohol, e.g., methyl alcohol. The etherification product is fractionally distilled into an overhead fraction containing essentially unreacted, light hydrocarbons and unreacted alcohol and into a bottoms fraction containing essentially the desired ether. The overhead fraction is condensed and cooled to resultant immiscible phases, of which one contains essentially the alcohol and the other contains essentially the hydrocarbons, are removed separately from each other. Water may be added to the overhead stream to facilitate the formation of the two liquid phases.