Molecular Dynamics Simulations of the liquid mixtures N, N-dimethylformamide-water using available potential models

This work reports the first computational study of N, N-dimethylformamide (DMF)-water mixtures performed by the molecular dynamics simulation (MDS) technique over the entire concentration range. The MDS results obtained have been used to assess the effectiveness of previously proposed potential models for pure liquid water (SPC, SPCE TIPS2) and DMF (CS2) in predicting certain properties of the DMF-water mixtures at ambient conditions. Thus, the sensitivity of the bulk thermodynamic and transport properties of the mixture to the details of the combined intermolecular potentials (CS2/SPC, CS2/SPCE, CS2/TIPS2) used has been obtained and discussed. Specifically, hydrogen bonds among the DMF and water molecules in the mixture are revealed in the behaviour of the concentration dependent appropriate (O-DMF-H-water, O-DMF-O-water) site-site pair distribution functions. Finally, the bulk thermodynamic results obtained have shown that among the three aforementioned potentials for water used, the SPC model, and TIPS2 to a lower extent, in combination with our CS2 model for pure liquid DMF provides the most accurate descriptions of the DMF-water mixtures. (C) 2002 Elsevier Science B.V. All rights reserved.