Structural characterization of propylammonium nitrate and N-methyl-2-pyrrolidone mixtures

Propylammonium nitrate (PAN)ionic liquid and N-methyl-2-pyrrolidone (NMP) are well know compounds employed for many applications in different industrial fields. The most interesting feature is the possibility of modulating the structural properties of the ionic liquid by mixing it with the molecular solvent. A dynamic characterization of the PAN-NMP mixtures is desirable to understand the significant effects on the structural properties and consequently on the chemical-physical features induced by the formation of such solutions. In order to improve the knowledge of the structure of PAN-NMP solutions, useful to the development of their applications, energy dispersive X-ray diffraction (EDXD), and molecular dynamics (MD) simulations were employed in this work. Our study evidenced a microheterogeneous solvation of PAN by NMP and indicate the presence of strong attracting interactions between the constituents. (C) 2016 Published by Elsevier B.V

Il novello Giasone

Nel 1671 il compositore Alessandro Stradella, con il supporto dei librettisti Giovanni Filippo Apolloni e Filippo Acciaiuoli, appront\uf2 per il Teatro Nuovo di Roma in Tordinona una versione notevolmente rimaneggiata del dramma per musica "Il Giasone" di Francesco Cavalli su testo di Giacinto Andrea Cicognini (Venezia 1649). L'edizione della partitura, a cura di Nicola Usula e Marco Beghelli con la consulenza di Lorenzo Bianconi, si avvale principalmente di due manoscritti dell'epoca, conservati a Siena (Biblioteca Comunale degli Intronati), e a Lisbona (Biblioteca da Ajuda

Calorimetric study of the selected nitroalkane plus chloroalkane binary systems. Comparison with DISQUAC predictions

Excess enthalpies, H (E), at 298.15 K and atmospheric pressure determined for 12 binary liquid mixtures containing nitromethane or nitroethane+1-chlorobutane, +1-chloropentane, +1-chlorohexane, +1,2-dichloroethane, +1,3-dichloropropane, and +1,4-dichlorobutane by means of a flow 2277-LKB microcalorimeter, are reported on over composition range. The experimental results, along with the literature data on vapor-liquid equilibrium (VLE), excess Gibbs energies, G (E), and activity coefficients at infinite dilution, , are interpreted in terms of DISQUAC group contribution model. The systems are characterized by three types of contact surface: nitro (NO2), chlorine (Cl), and alkyl (CH3, CH2). The interchange energy parameters of the alkyl/NO2 and alkyl/Cl contacts were determined independently from the study of alkane+nitroalkane and alkane+chloroalkane systems. The structure-dependent interchange parameters of the NO2/Cl contact are reported in this work. The model provides a fairly consistent description of the VLE and of thermodynamic functions G (E), H (E), , for all investigate

The structural organization of N -methyl-2-pyrrolidone + water mixtures: a densitometry, x-ray diffraction, and molecular dynamics study

A combined approach of molecular dynamics simulations, wide angle X-ray scattering experiments, and density measurements was employed to study the structural properties of N-methyl-2-pyrrolidone (NMP) + water mixtures over the whole concentration range. Remarkably, a very good agreement between computed and experimental densities and diffraction patterns was achieved, especially if the effect of the mixture composition on NMP charges is taken into account. Analysis of the inter- molecular organization, as revealed by the radial and spatial distribution functions of relevant solvent atoms, nicely explained the density maximum observed experimentally

NMR, calorimetry, and computational studies of aqueous solutions of N-methyl-2-pyrrolidone

N-Methyl-2-pyrrolidone (NMP) is a solvent with applications in different industrial fields. Although largely employed in aqueous mixtures, little is known on the structural and dynamic properties of this system. In order to improve the knowledge on NMP aqueous solutions, useful to the development of their applications, NMR spectroscopy, calorimetric titration, and puckering analysis of molecular dynamics (MD) simulations were employed in this work. Our calorimetric study evidenced the presence of strong interactions between NMP and water and revealed that, under comparable conditions, the solvation of NMP by water results in an interaction stronger than the solvation of water by NMP. Overall, the changes of H-1 and C-13 chemical shifts and 2D ROESY spectra upon dilution suggested a preferential location of water nearby the carbonyl group of NMP and the formation of hydrogen bonding between these two molecules. In parallel, observation of correlation times by C-13 NMR spectroscopy evidenced a different dynamic behavior moving from the NMP-rich region to the water-rich region, characterized by a maximum value at about 0.7 water mole fraction. MD simulations showed that the NMP conformation remains the same over the whole concentration range. Our results were discussed in terms of changes in the NMP assembling upon dilution

Thermo-​physical properties of ammonium-​based ionic liquid + N-​methyl-​2-​pyrrolidone mixtures at 298.15 K

A systematic study of a series of room-temperature ionic liquids, belonging to the alkylammonium nitrate family (XAN), was carried out at 298.15 K and 0.1 MPa with the aim of investigating the effect of the cationic chain length on some thermo-physical properties and their behavior in the organic solvent N-methyl-2-pyrrolidone (NMP), over the whole concentration range. Experimental densities were used to calculate molar volumes, Vm, and excess molar volumes, VE. Complementary information was obtained by isothermal titration calorimetry that provided the values of the heat of mixing, HE, and the excess partial molar enthalpies of each component, HE 1 and HE 2. The density values of neat XAN samples as the alkyl chain length of the cation increases, whereas, the addition of the methoxy group to the considered smaller alkyl chain resulted in an increase of density. Negative VE and HE values were found for each XAN + NMP system, indicating the presence of strong attracting interactions between the constituents

I ritratti del Museo della Musica di Bologna da padre Martini al Liceo musicale

Intorno al 1770 il francescano Giambattista Martini (1706-1784) avvi\uf2 nel convento di San Francesco in Bologna una raccolta di ritratti di musicisti, contemporanei e del passato. Tra i tanti pezzi prelibati che l\u2019insigne teorico, erudito e storico della musica seppe attrarre da ogni parte d\u2019Italia e d\u2019Europa spiccano \u2013 per citare soltanto i pi\uf9 famosi \u2013 il J.C. Bach di Gainsborough, il Farinelli di Corrado Giaquinto, un ritratto di Mozart ventunenne, oltre al trompe-l\u2019\u153il degli scaffali di libreria di G.M. Crespi. Con l\u2019istituzione del Liceo musicale (1804) la collezione pass\uf2 alla citt\ue0 di Bologna e sull\u2019arco di due secoli si \ue8 viepi\uf9 arricchita: basti ricordare i ritratti di Isabel Colbran, Rossini, Martucci, M.E. Bossi, nonch\ue9 l\u2019Arrigo Serato di Casorati. Dei 312 ritratti \u2013 oggi uno dei vanti del Museo della Musica \u2013 circa la met\ue0 riguardano membri dell\u2019Accademia Filarmonica, fondata nel 1666, e docenti del Liceo musicale, poi Conservatorio statale. Il catalogo generale dell\u2019iconoteca, frutto del lavoro di una \ue9quipe di storici dell\u2019arte e della musica avviato nel 1984, ne descrive analiticamente storia e contenuto. Tutti i dipinti sono riprodotti a colori, 58 di essi a piena pagina

The Structure of Ionic Liquids

Research in the field of ionic liquids (ILs) keeps a fast and steady pace. Since these new-generation molten salts first appeared in the chemistry and physics landscape, a large number of new compounds has been synthesized. Most of them display unexpected behaviour and possess stunning properties. This volume describes the most recent findings on the structure of ILs interpreted through cutting-edge experimental and theoretical methods. Ranging from the mesoscopic structure of ILs to their interaction with proteins, the reader will learn about how diffraction techniques (small and large angle X-Ray and neutron scattering, powder methods), X-Ray absorption spectroscopies (EXAFS/XANES), optical methods (IR, RAMAN), NMR and calorimetric methods can help in investigating the field of ILs, both as neat liquids and in mixtures with other compounds, and how to choose the best method to suit his experimental needs. A detailed survey of theoretical methods, both quantum-chemical and classical, and of their predictive power will accompany the exposition of experimental ones. This book is a must read for postgraduate students, post-docs and researchers who are interested in understanding the structural properties of ILs