Distillative separation of liquid mixtures containing aliphatic alcohols
AssigneeBASF SE
InventorsGerd Kaibel, Horst Hartmann, Waldhelm Hochstein, Franz-Josef Mueller
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Abstract
Liquid mixtures containing aliphatic alcohols are separated, by distillation, into a higher-boiling alcohol-containing fraction and a lower-boiling fraction containing the other liquids, by carrying out the fractionation in the presence of water and of an alkanal and, over about 3/4 of the column height, in the presence of a non-volatile or only slightly volatile acid.
Claims6
A process for the distillative separation in a fractionating column of a liquid mixture containing at least one aliphatic alcohol into a higher-boiling alcohol-containing fraction and a lower-boiling fraction of the other liquids, which process comprises:
- contacting the alcohol in a middle zone of the column with a C.sub.2 - to C.sub.5 -alkanal and with a non-volatile or only slightly volatile acid;
- maintaining said middle zone of the column under conditions of temperature and pressure sufficient to cause a transient bonding of the alcohol to the alkanal in the presence of said acid so as to form a higher boiling acetal or hemiacetal;
- heating the column such that substances more volatile than the alcohol pass into the upper zone of the column for removal therefrom as a top product;
- cleaving said acetal or hemiacetal in the lower zone of the column into its respective alcohol and alkanal components;
- and
- separating the alcohol from the bottom product of the column.
Dependencies are inferred from the claim text.