acetylenes are selectively hydrogenated mercaptans are reacted with diolefins and isoolefins are isomerized the isomerization under the conditions of hydrogenation is of the bond type and very little if any skeletal isomerization occurs in the present process the sulfides formed from the reaction of the mercaptans with the diolefins are higher boiling than the c 5 39 s and are distilled downward and removed with the bottoms hydrogenation is the reaction of hydrogen with a carbon carbon multiple bond to 34 saturate 34 the compound this reaction is usually carried out at super atmospheric pressures and moderate temperatures using an excess of hydrogen over a metal catalyst among the metals known to catalyze the hydrogenation reaction are platinum rhenium cobalt molybdenum nickel tungsten and palladium generally commercial forms of catalyst use supported oxides of these metals the oxide is reduced to the active form either prior to use with a reducing agent or during use by the hydrogen in the feed these metals also catalyze other reactions most notably dehydrogenation at elevated temperatures additionally they can promote the reaction of olefinic compounds with themselves or other olefins to produce dimers or oligomers as residence time is increased selective hydrogenation of hydrocarbon compounds has been known for quite some time peterson et al in 34 the selective.