The reactivities and reaction pathways of C-7 alkenes over a CoMo/Al2O3 hydrotreating catalyst were studied using both model-compound feeds and heavy catalytic naphtha (HCN). The three C-7 compounds studied included a normal alkene (1-heptene), an isoalkene (2-methyl-1-hexene), and a cycloalkene (1-methylcyclohexene). All three compounds underwent double bond isomerization and hydrogenation, but only the iso- and cycloalkenes reacted by skeletal isomerization. No appreciable amounts of cyclization products were observed. The rates of hydrogenation were of the order normal alkenes (heptenes) > isoalkenes (methylhexenes) > cycloalkenes (methylcyclohexenes). The distributions of the unconverted alkenes for each type of compound generally approached predicted equilibrium values as the reaction temperature increased. The alkenes in HCN showed the same order of reactivity and similar activation energies as in the model compound studies. These HCN studies also revealed the dependence of the reactivity on the length of the carbon chain as C-6 > C-7 > C-6.