MACROMOLECULES MODELING THE EFFECT OF SOLVENTS ON ASPHALTENE AGGREGATES Alexandre N.M. Carauta1, Julio C.G. Correia2, Daniel M. Silva1, Peter R. Seidl1,3, Erika C.A.N.Chrisman3, Sonia M.C. de Menezes4, Wladimir F. de Souza4, Marco A.G. Teixeira4 1 Programa de Pós-graduação em Química Orgânica, Instituto de Química, Universidade Federal Fluminense, Niterói, RJ, 2CETEM, Rio de Janeiro, RJ, Brazil 3Departamento de Processos Orgânicos, Escola de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil, 4CENPES, PETROBRÁS, Rio de Janeiro, RJ, Brazil Asphaltene deposition is a well-known problem in the petroleum industry. Nevertheless there seems to be a lack of information on the processes involved in asphaltene association and its relationship to asphaltene solubility under certain conditions. Molecular mechanics and dynamics have played an important role in the investigation of association phenomena and the way it is affected by different solvents. In order to better understand the role of solvents in fractionating asphaltenes extracted from vacuum residues and evaluate their solubility under different conditions we modeled the effect of toluene, n-butane, isobutane and heptane on an aggregate formed by representative asphaltene molecules. Molecular dynamic simulations were run on asphaltene dimer after minimizing the conformation of each molecule and verifying the most stable position for docking. They reveal the extent that these solvents are able to separate the aggregate at a certain temperature after a given period of time. As expected toluene is the most effective and heptane affects the aggregate the least, n-butane and isobutane falling in between.