Density and Viscosity of N-Methylacetamide–Calcium Chloride Mixtures over the Temperature Range from 308.15 to 328.15 K at Atmospheric Pressure

Abstract

The values of densities in N-methylacetamide solutions of calcium chloride have been measured at atmospheric pressure using an Anton Paar digital vibrating U-tube densimeter at temperatures ranging from 308.15 to 328.15 K, ΔT = 5 K and in the concentration range from 0 to 0.355 mol·kg–1. The kinematic viscosity for these mixtures has been measured at the same thermodynamic conditions using an Ubbelohde viscometer. Partial molar volumes of N-methylacetamide; partial molar volumes and apparent molar volumes of calcium chloride, and thermal expansion coefficients of solutions have been calculated using the experimental values. Dependences of these properties on the electrolyte concentrations have been discussed.

Density and Viscosity of Magnesium Chloride Solution in N-Methylacetamide over the Temperature Range from 308.15 to 328.15 K at Ambient Pressure

“…The growth in the salt molality leads to a decrease in the values of both the partial molar volume (Figure ) and the coefficient of thermal expansion (Figure ). A similar picture for lithium, zinc, and calcium chlorides was observed in refs − . Apparently, this is due to the solvation processes occurring in the solutions.…”

“…However, this process is not dominant. A similar picture is observed in NMA solutions with lithium, calcium, and zinc chlorides. − …”

“…These characteristics allow it to dissolve many compounds well, and its small molecule is very convenient for studying the effect of hydrogen bonds of peptide groups, which are the basis of the protein structure. Being a mimetic of the structure of amino acids, NMA attracts the attention of many researchers. − This is a good model compound for studying hydrogen bonds between groups of peptides and is widely used as a model of peptides and membranes during computer simulation. ,− …”

Density and Viscosity of Zinc Chloride Solution in N-Methylacetamide over the Temperature Range from 308.15 to 328.15 K at Atmospheric Pressure

“…Data on the density of solutions of lithium chloride and calcium chloride , in N -methylacetamide at temperatures of 308.15–328.15 K were previously published. From these data on the equations presented in this article, the volumetric properties of electrolytes were calculated.…”

“…On the other hand, N -methylacetamide (NMA) is a well-known mimetic of protein interfaces . NMA is also widely used as a model of peptides − because it is suitable for modeling hydrogen bonds between peptide groups. , Despite the importance of NMA as a solvent, there are a very limited number of scientific publications reporting experimental studies of the properties of electrolyte solutions in NMA over wide ranges of concentration and temperature. − …”