Process For Purifying a Stream Comprising 1,4-Butanediol

A process for purifying a stream comprising 1,4-butanediol comprising the steps of:

• (a) supplying a crude product stream comprising 1,4-butandiol and one or more of γ-butyrolactone, 2-(4-hydroxybutoxy)-tetrahydrofuran, 4-hydroxybutyl(4-hydroxybutyrate), and 3-(4-hydroxybutoxy)-tetrahydrofuran to a first distillation column;
• (b) removing a side-draw comprising 1,4-butanediol, and light components, said light components including at least some of those produced by reaction in the first distillation column;
• (c) passing the stream to a hydrogenation zone;
• (d) subjecting the stream from step (c) to hydrogenation in the hydrogenation zone in the presence of a hydrogenation catalyst, and recovering from the hydrogenation zone a 1,4-butanediol product stream having a reduced content of 2-(4-hydroxybutoxy)-tetrahydrofuran, and optionally additionally including (4-hyroxybutyl)-4-hydroxybutyrate formed by reaction of γ-butyrolactone;
• (e) passing the 1,4-butaendiol product stream from step (d) to a second distillation column operated such that (4-hyroxybutyl)-4-hydroxybutyrate is removed as a bottom stream and removing a 1,4-butanediol stream as overhead;
• and
• (f) passing the overhead stream removed in (e) to a third distillation column and recovering a purified 1,4-butanediol stream.