TELEEDUCATION: BUTANE CONFORMATIONS
Last Update 18/6/1998
The rotation of carbon atoms around single bonds generates conformations in the butane molecule, resembling ethane . In butane the lowest energy conformation is named anti or anti 180 o or staggered 180 o. The next conformation, named gauche or gauche 60 o or staggered 60o, belongs to a 3.4 kJ mole-1 higher energy level. Next is the eclipsed CH3/H or eclipsed 120 o conformation, at an energy level 14.2 kJ mole-1 higher than the anti. The conformation named eclipsed CH3/CH3 or eclipsed methils or eclipsed 0 o takes place. It demands from 18.4 to 25.5 kJ mole-1 more than the anti conformation to occour. You can click with the mouse when the cursor is pointing any of the buttons and observe the respective conformation. The blue balls represent the hydrogen bonded to the gray and dark coloured carbon atoms and the red balls represent the methils bonded each to a different carbon atom. If you push and drag the mouse properly when the cursor is over the green square, you can animate the butane from one conformation to the other.
Please send your comments to: Prof. Dr. Roberto A. Müller, e-mail: rmueller@mail.ufv.br