Role of solvent accessible surface area in the conformational equilibrium of n-butane in liquids

► Theoretical calculations and computer simulations have shown that both water and carbon tetrachloride affect the conformational equilibrium of n-butane, favouring the more compact conformations. ► We have devised a very simple theoretical approach grounded on the basic notion that the fundamental difference among the various n-butane conformations is the solvent-excluded volume they produce, as measured by the solvent accessible surface area. ► The calculated dependence of the conformational Gibbs energy upon the dihedral angle is qualitatively similar in water and carbon tetrachloride, and in more-than-qualitative agreement with those calculated by means of more sophisticated approaches. ► The quantitative difference between water and carbon tetrachloride is because the magnitude of the work of cavity creation is markedly larger in the former liquid due to the smallness of its molecules.