| abstract |
A crude product stream of 1,4-butandiol and one or more of γ-butyrolactone, 2-(4-hydroxybutoxy)-tetrahydrofuran, 4-hydroxybutyl(4-hydroxybutyrate), and 3-(4-hydroxybutoxy)-tetrahydrofuran is supplied to a first distillation column. A side-draw of 1,4-butanediol and light components is removed, with the light components including at least some of those produced by reaction in the first distillation column. The stream is passed to a hydrogenation zone and subjected to hydrogenation in the presence of a hydrogenation catalyst. A 1,4-butanediol product stream having a reduced content of 2-(4-hydroxybutoxy)-tetrahydrofuran is recovered and passed to a second distillation column operated such that (4-hyroxybutyl)-4-hydroxybutyrate is removed as a bottom stream and a 1,4-butanediol stream is removed as overhead. The overhead stream removed is passed to a third distillation column and a purified 1,4-butanediol stream is recovered. |