Search results for "Volume contraction"
showing 2 items of 2 documents
Viscous Synergy of Pure Monoalcohol Mixtures in Water and Its Relation to Concentration
2004
Pure or aqueous alcohols are the solvents most widely used in industry, including in the manufacture of pharmaceuticals and cosmetic products. However, water–alcohol mixtures generate hydrogen-bonded molecular associations that lead to volume contraction and an increase in viscosity greater than that expected in the absence of any interaction between the components of the mixture. This phenomenon is referred to as viscous synergy. The present study investigates viscous synergy in monoalcohol systems containing up to five carbon atoms, since beyond hexanol all alcohols are practically insoluble in water. In all cases, determinations were made of the proportions of water and alcohol for which…
Rheological study and thermodynamic analysis of the binary system (water/ethanol): Influence of concentration
2004
Water is the most widely used solvent in the chemical and pharmaceutical industry, since it is the most physiological and best tolerated excipient. However, in some cases water cannot be used as a solvent because the active substance or solute is insoluble or only slightly soluble in water. For this and other reasons, nonwater solvents may be used possessing the common characteristic of being soluble or mixable in water; as a result, such solvents can be used to prepare binary or tertiary mixtures, etc., with different purposes such as increasing water solubility, or modifying the viscosity or absorption of the dissolved substance, for example. Ethanol, along with other alcohols either alon…