Conformations of Propane Propane(CaHa)torsional barrier around the carbon- carbon bonds 14 kJ/mol ■ Eclipsed conformer of propane has two ethane-type H- H interactions and an interaction between C-H and C- C bond 6.0 kJ/mol CH Rotate rear carbon60° 、HH HH 4.0 k.J/mol 4.0 k.J/mol ered propane Eclipsed propane In butane,not all the staggered conformations have the same energy,and not all the eclipsed conformations have the same energyConformations of Propane „ Propane (C 3 H 8) torsional barrier around the carbon– carbon bonds 14 kJ/mol „ Eclipsed conformer of propane has two ethane-type H– H interactions and an interaction between C–H and C– C bond „ In butane, not all the staggered conformations have the same energy, and not all the eclipsed conformations have the same energy