Abstract: An improved method for removing formaldehyde from a crude butynediol product stream comprising the step of providing a crude butynediol stream containing butynediol and formaldehyde. A pH control agent is then mixed with the crude butynediol stream to form a treated product stream, wherein the pH of the treated product stream is raised to a level that limits the reaction of butynediol and formaldehyde to form acetal complex and decrease the solubility of trace metals. The treated product stream then flows into the inlet of a continuous distillation column. Finally, a concentrated formaldehyde stream from the overhead stream of the distillation column and a concentrated butynediol stream from the distillation bottoms stream that is essentially free of formaldehyde and acetal complex are both recovered.

Abstract: A distillation process for the preparation of purified concentrated BDO.High boiling impurities, including color formers, precursors of color formers and tar formers are removed from the BDO early in the process and under mild conditions.