Patent ID: 6846389
Filing Date: 2005-01-25
Classification: B01D,C07C,C07D,Y10S

Abstract:
1. A process for the continuous fractional distillation of a mixture comprising tetrahydrofuran, γ-butyrolactone and/or 1,4-butanediol to give at least three fractions, said fractions comprising a low boiling fraction, an intermediate-boiling fraction and a high boiling fraction, wherein the fractional distillation is carried out in an assembly of distillation columns comprising at least one dividing wall column or at least one assembly of thermally coupled distillation columns, each dividing wall column and each assembly of thermally coupled columns comprising a top section (1), an upper feed section (2), an upper offtake section (3), a lower feed section (4), a lower offtake section (5), and a bottom section (6), which sections, during fractional distillation, comprise a stream of downflowing liquid and a stream of vapor, and wherein said assembly of distillation columns comprises at least one distillation block selected from the group consisting of (B1) a distillation block for separating off tetrahydrofuran, (B2) a distillation block for separating off γ-butyrolactone, and (B3) a distillation block for separating off 1,4-butanediol, and the products being isolated in the order (B1) before (B2) before (B3), corresponding to their boiling points.