2026-04-03T22:15:39Zhttps://recercat.cat/oai/request

oai:recercat.cat:2445/1941232025-12-05T14:12:36Zcom_2072_1057col_2072_478815col_2072_478917

00925njm 22002777a 4500 dc Cunha, Renato D. author Ferreira, Livia J. author Orestes, Ednilsom author Coutinho-Neto, Mauricio D. author Almeida, James M. de author Carvalho, Rogério M. author Maciel, Cleiton D. author Curutchet Barat, Carles E. author Homem-de-Mello, Paula author 2023-02-24T09:16:54Z 2023-02-24T09:16:54Z 2022-09-22 2023-02-24T09:16:54Z Naphthenic Acids (NA) are important oil extraction subproducts. These chemical species are one of the leading causes of marine pollution and duct corrosion. For this reason, understanding the behavior of NAs in different saline conditions is one of the challenges in the oil industry. In this work, we simulated several naphthenic acid species and their mixtures, employing density functional theory calculations with the MST-IEFPCM continuum solvation model, to obtain the octanol-water partition coefficients, together with microsecond classical molecular dynamics. The latter consisted of pure water, low-salinity, and high-salinity environment simulations, to assess the stability of NAs aggregates and their sizes. The quantum calculations have shown that the longer chain acids are more hydrophobic, and the classical simulations corroborated: that the longer the chain, the higher the order of the aggregate. In addition, we observed that larger aggregates are stable at higher salinities for all the studied NAs. This can be one factor in the observed low-salinity-enhanced oil recovery, which is a complex phenomenon. The simulations also show that stabilizing the aggregates induced by the salinity involves a direct interplay of Na+ cations with the carboxylic groups of the NAs inside the aggregates. In some cases, the ion/NA organization forms a membrane-like circular structural arrangement, especially for longer chain NAs. Keywords: naphthenic acids; molecular dynamics; MST-IEFPCM; log P; aggregation; solvation; salinity Dinàmica molecular Química quàntica Molecular dynamics Quantum chemistry Naphthenic Acids Aggregation: The Role of Salinity