Dimethyl formamide when used as an absorption solvent to remove acetylenes from olefin-containing gas streams acts as well as a promoter for the oxidative conversion of H.sub.2 S, COS and/or CS.sub.2, also contained in the feed stream, to elemental sulfur. Thus both acetylenes and sulfur compounds are efficiently removed from such olefin-containing gas streams as coke oven gas. Further, the loss of dimethyl formamide entrained and vaporized by the deacetylenized gas stream leaving the dimethyl formamide absorber is substantially reduced or effectively eliminated by the injection of a stream of liquid selected from the group consisting of paraffinic hydrocarbons having 4-8 carbon atoms per molecule containing at least one tertiary carbon atom per molecule and aromatic hydrocarbons having 6-10 carbon atoms per molecule above the point of injection of the dimethyl formamide solvent stream to the absorption column. This liquid stream injection is particularly advantageous when the stream is also a reactant in a downstream alkylation process.