TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: The catalyst comprises palladium on aluminum oxide, titanium dioxide, zirconium oxide, and/or silicon dioxide as a support.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The process is performed in a fixed bed. The hydrogenation is conducted with a liquid circulation system with a weight ratio of recycle stream to feed stream of 2:20. A stream which is obtained from gas scrubbing of acetylene and has an organic solvent other than hydrocarbons is used, in which, based on butadiyne, up to 20 wt.% of vinylacetylene and up to 10 wt.% of acetylene are present. Preferred Component: The butadiyne is present in an organic solvent other than hydrocarbons. The solvent used is N-methylpyrrolidone, dimethylformamide, acetone, furfurol, acetonitrile, and/or dimethylacetamide. The stream comprises 1-10 wt.% of butadiyne based on the overall stream. EXAMPLE - Catalyst (6.3-25 g) comprising 0.19-0.24 wt.% of palladium on gamma -aluminum oxide was initially charged in a tubular reactor with an internal diameter of 4 mm. The total length of the catalyst bed was 360 cm. Four thermocouples were distributed over the length of the catalyst bed. Fresh starting mixture, recyclate and hydrogen were introduced into the reactor at the bottom. The exit stream from the reactor was divided in a separator into a gas stream and a liquid stream. The liquid stream was again divided into a recycle stream and a product stream. The recycle stream was fed to the reactor via a pump. The catalyst was reduced in the reactor before the start of the reaction under 10 L/hour of hydrogen at 120 degrees C for 16 hours. The mixture used contained 1.5-3.5 vol.% of butadiyne and 0.5-1.5 vol.% styrene in N-methylpyrrolidone (NMP) and was obtained from an acetylene stripper. The reaction temperature was 25-80 degrees C at a total pressure of 10-20 bar. The feed was 10 g/hour of NMP solution. The recycle ratio was 1:4, i.e. 40 g/hour of recycled mixture were conducted into the reactor with 10 g/hour of fresh feed. The liquid samples of the product were analyzed by gas chromatography. The mixture used in the process contained 61-74% NMP, 0.3-0.5% styrene, 8-12% toluene, ethylbenzene and xylene, 8-22% benzene and 3-4% butadiyne (area percent determined by gas chromatography). Butadiyne was no longer detectable in the reaction product, as it had been hydrogenated to butane and butenes. Overall experiments were carried out at 20 degrees C and 10 bar, 80 degrees C and 10 bar, and 40 degrees C and 20 bar. In each case, full butadiyne hydrogenation was achieved.