the invention is used to purify hydrocarbon streams being less than 50 mol c4 hydrocarbons with or without added oxygen and such streams may have less than 20 mol or less than 10 mol c4 hydrocarbons based on the hydrocarbon content such modifications are also to be considered as part of the present invention as can be seen clearly the instant invention affords a novel process to selectively remove acetylenic impurities from a hydrocarbon mix without detrimentally affecting the desired diolefins there is provided in one aspect of the invention a vapor phase process for selective removal of at least 80 mole of acetylenic impurities from an input gaseous stream wherein said input stream comprises c1 to c9 unsaturated hydrocarbon monoolefins and diolefins acetylenic impurities and steam with or without substantial amounts of added hydrogen or oxygen wherein said process comprises contacting said input stream in the vapor phase at a temperature in the range of about 250 u00b0 c 480 u00b0 f to about 900 u00b0 c 1650 u00b0 f with a solid zinc free catalyst said catalyst derived from and preferably including oxides carbonates and or hydroxides of ba ni na and fe wherein said ba is present in about 0 25 40 wt on dry basis of said catalyst ni is present.