Interactions among trioctylamine-sulfuric acid-water: experiments and molecular dynamics simulations

Abstract

Trioctylamine (TOA) has been widely regarded as a cost effective extractant and received extensive applications in the metallurgical industry. However, TOA is prone to aggregate and form something like viscoelastic material when it meets the sulfuric acid. However, there is no unified understanding of the mechanism of aggregation. Based on the possible molecular interaction model proposed in our previous work, we are going to probe the interaction of TOA and the sulfuric acid as well as to obtain a chemical structure corresponding to various molar ratios through molecular dynamics calculations together with a specific distance distribution function. The results show that the hydrogen bonding of the whole system strengthens with the increase of the molar ratio of sulfuric acid and water to TOA. When the molar ratio of sulfuric acid and water to TOA is comparatively low, the hydrogen bonds interactions between TOA and water was predominated. When the ratio is high, TOA will react with sulfuric acid through protonation. The results of the simulation is consistent with our previous studies.