Effect of hydrotropes on solubility and mass transfer coefficient of organic acids and 6 gingerol

Abstract

In the present work a comprehensive study on the effect of hydrotropes such as sodium salicylate, sodium benzoate, nicotinamide and urea on the solubility and mass transfer coefficient of a series of organic acids such as salicylic acid, acetylsalicylic acid, p-aminobenzoic acid, 2-nitrobenzoic acid and stearic acid has been carried out.Data on various aspects of hydrotropic study on the solubility and mass transfer coefficient for a series of organic acids have been provided for the first time. The experimental solubility data for various solutes at different temperatures have been analyzed using the modified Setchenow equation, log10[S/Sm] = Ks [Cs-Cm] where S and Sm are the solubilities of the acid at any hydrotrope concentration Cs and minimum hydrotrope concentration Cm respectively. Setschenow constant, Ks, a measure of the effectiveness of the hydrotrope has been determined for each case. To propose a possible mechanism of hydrotropic phenomenon, the solution properties of hydrotropes like viscosity, specific gravity, surface tension, specific conductance and refractive index have been determined for a range of hydrotrope concentrations (0 - 2.0 mol/L) . All hydrotropes used in this work showed an enhancement in the solubility and mass transfer coefficient to different degrees. The maximum enhancement factor, which is the ratio of the value in presence and absence of a hydrotrope, has been determined for both the cases The percentage recovery of organic acids from hydrotrope solutions were determined by simple dilution of hydrotrope solution with distilled water at any concentration between MHC and maximum hydrotrope concentration (Cmax). A similar study has been carried out for bioactive compound 6-gingerol under the influence of different hydrotrope concentrations (0 -1.50 mol/L) at 303K. The implications of the study have been fully discussed and the scope for future research has been suggested newline