Densities and ultrasonic speed of 2-hydroxy-5-methyl-3-nitro acetophenone in N,N-dimethylformamide at different temperatures

Abstract

ABSTRACT. Density, ultrasonic speed measurements have been made for 2-hydroxy-5-methyl-3-nitroacetophenone (HMNAP) (0.06-0.21 mol . kg -1 ) in N,N-dimethylformamide (DMF) at four equidistant temperatures: 298.15, 303.15, 308.15 and 313.15 K. These measurements have been used to evaluate some important thermodynamic and acoustic parameters, such as apparent molar volume, limiting apparent molar volume, adiabatic compressibility, apparent molar adiabatic compressibility, limiting apparent molar adiabatic compressibility. The apparent molar volume (Vφ) and apparent molar adiabatic compressibility (Ks,φ), were computed using density data. These parameters, were used to discuss interactions between the ketonic (>CO) group and DMF molecule. The results are interpreted to gain insight in to the changes in molecular association equilibria and structural effects in these systems.

Acoustic and Thermo-Dynamical Investigation of 2-Amino-5-Nitrothiazole- DMSO-Water System at Different Temperatures and Concentration

“…It has been observe that the change in speed of sound depends on the structure and properties of solute. Therefore, the solutes which increase the ultrasonic velocity are structure maker while those decreases the ultrasonic velocities are structure breakers [13]. The decrease in ultrasonic velocity shows that the interaction between solute and solvent is becoming less dominant.…”

“…Addition of the organic solute to the solvent not only allows stronger association in between solvent and solute molecules but also allows closer approach of solute and solvent molecules. This tends to decrease in the volume and an increase in the density of the solution [12,13]. From Figure 3 it observe that at high temperature heteromolecular and homomolecular clusters breaks which leads to the decrease in values of speed of sound with increase in temperature [14].…”

Interaction studies of methyl acetate in aqueous solutions of quinoxaline derivatives: Effect of temperature and concentration

“…The sound velocity values increases or decreases depending on solute structure and their properties. Therefore, the methyl acetate which increases the sound velocity acts as structure maker [41]. The density and sound velocity values of the studied mixtures are not exactly the same but there are very slight variations due to the nature of quinoxaline derivatives studied.…”

“…An increase in concentration allows for a closer approach of solvent and solute molecules, and stronger association between solute and solvent molecules [41]. The sound velocity values increases or decreases depending on solute structure and their properties.…”

Commercially available ammonium salt-catalyzed efficient dehydration of fructose to 5-hydroxymethylfurfural in ionic liquid

“…Additionally, DMSO acted as both an electron accepter and an electron donator to improve the dehydration of fructose [27]. Similarly, DMF might work like DMSO in the dehydration reaction due to its strong electron pair donating and accepting ability [28] and had been proved to be preferable in the fructose dehydration in the previous study [29]. However, DMSO and DMF, as aprotic solvents, might bind the free H + in the solvent and absorb on the acid sites of the catalyst to inhibit or block the reaction [27], resulting in slight reduction of HMF yields when adding a minute quantity of (NH 4 ) 2 S 2 O 3 .…”