More substituted alkenes are more stable than less substituted ones due to hyperconjugation. They have a lower heat of hydrogenation. The following illustrates stability of alkenes with various substituentsD. RogersRogers, D.W.; Choi, L.S.; Girellini, R.S. Heats of hydrogenation and...
The enthalpies of reduction of carbonyl compounds and hydrogenation of alkenes have been calculated at the HF, B3LYP, M06, MP2, G3, G4, CBS-QB3, CBS-APNO, and W1BD levels and, in the case of the first four methods, using a variety of basis sets up to aug-cc-pVTZ. The results...