GASEOUS HEATS OF HYDROGENATION OF SOME CYCLIC AND OPEN-CHAIN ALKENES

Gaseous heats of hydrogenation at 25°C [AHH2(g)] have been calculated for cyclohexene, 1-methylcyclopentene, cycloheptatriene, 1-methylcyclohexene, methylenecyclohexane, 1-ethylcyclopentene, ethylidenecyclopentane, 1,3,5,7-cyclooctatetraene, ethylidenecyclohexane, vinylcyclohexane, allylcyclopentane, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 1-hexadecene, and trans-2,2,5,5-tetramethyl-3-hexene, based on previously measured solution values of ΔHH2, and experimental heats of vaporization and heats of solution of the alkenes and the hydrogenation products. Calculated ΔHH2(g) values are from 0.4 kcal/mol less exothermic to 2.5 kcal/mol more exothermic than experimental values in solution, and 0.4-1.2 kcal/mol less exothermic than experimental gaseous values measured at 82°C. Gaseous heats of formation of 2,2,5,5-tetramethylhexane and cyclooctatetraene have been calculated from ΔHH2(g) values. ΔHH2(g) values from various sources are compared. © 1979 American Chemical Society.