Eur. Phys. J. E (2013) 36: 129
https://doi.org/10.1140/epje/i2013-13129-5

Regular Article

Structural investigations of N-methylformamide-water mixtures at various concentrations

¹ Laboratoire Physico-Chimie des Matériaux, Département de Physique, Faculté des Sciences de Monastir, Université de Monastir, 5000, Monastir, Tunisie
² Department of Physics, Faculty of Sciences, Jazan University, Jazan, KSA
³ Laboratoire de Spectroscopie Atomique, Moléculaire et Applications, Département de Physique, Faculté des Sciences, Université de Tunis-El Manar, 1060, Tunis, Tunisie

^* e-mail: salah_nasr1@yahoo.fr

Received: 15 May 2013
Revised: 9 September 2013
Accepted: 18 October 2013
Published online: 21 November 2013

Abstract

Structural investigations of N-methylformamide-water mixtures (NMF-water) are performed at room temperature and atmospheric pressure for two water molar fractions x _w = 0.66 and x _w = 0.75 . This paper extends our recent study on the equimolar system. H-bond networks are preferentially formed between NMF and water molecules. Among a large variety of DFT optimized models, X-ray scattering data shows that the local order of each mixture is better described by a tetramer where one NMF molecule is connected to three water molecules. No self-association is observed in the considered systems. The effect of hydration is compared to the temperature and pressure effects in some hydrogen-bonded liquids.