Study of Physical Adsorption for Ethanol Gasoline on Metal Surfaces

Using molecular simulation technology based on classical mechanic methods, the physical adsorption conformation of the representative conventional gasoline molecule, ethanol molecule and its oxidation intermediates, including acetaldehyde and acetic acid, on different metal surfaces was performed. Furthermore, the interaction energy composed of van der Waals and electrostatic between the absorbed molecules and the metal surfaces was calculated to study the influence of ethanol gasoline on the metal materials in comparison with the conventional gasoline. The results concluded that iron is the most likely to make strong physical adsorption with organic molecules than other surfaces, whether it is conventional gasoline molecule or ethanol molecule, or the oxidation intermediates. It may be related to the crystal configuration, coordination, atomic electron distribution and orbitals distribution of iron surface. The most stable among the studied surfaces is copper, followed by aluminum. Acid molecules, due to the presence of carboxyl group, are the most prone to form strong adsorption on the metal surfaces. The functional additives, such as antioxidant, stabilizer, detergent, dispersant or corrosion inhibitor, were critical for ethanol gasoline to avoid the undesirable influences. ESP distribution and the charges of the module molecules were calculated to make further analysis based on quantum theory.