Effects of Temperature on the Structure and Dynamics of Aqueous Mixtures of N,N-Dimethylformamide

Biswas, S and Mallik, Bhabani Shankar (2014) Effects of Temperature on the Structure and Dynamics of Aqueous Mixtures of N,N-Dimethylformamide. Journal of Chemical and Engineering Data, 59 (10). pp. 3250-3257. ISSN 0021-9568

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Abstract

The hydrogen-bonded structure and dynamics of aqueous N,N-dimethylformamide (DMF) solutions of varying compositions are investigated by means of molecular dynamics simulations at three different temperatures at ambient pressure. The dynamical aspects of the solution are investigated in terms of the single-particle and mutual diffusion coefficients, calculated from the mean square displacement, and also in terms of the lifetimes of water–water and water–DMF hydrogen bonds. The calculated densities and diffusion coefficients at different temperatures are compared with the available experimental data; it is observed that they agree qualitatively with the experimental data and reproduce the general trends within the limitations of adopted force fields. With the increase in DMF concentrations, the water–water hydrogen bonding is less preferred, facilitating the water–DMF association; the lifetimes of both type of hydrogen bonds increase due to existence of long-lived clusters of molecules. The effects of temperature on dynamics of water–DMF hydrogen bonds have significant contribution toward the microheterogeneity of the systems at higher DMF mole fractions.

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