The Solubility of Cucurbit[5]uril in Pure Water and Hydrochloric Acid at Different Temperature and Some Relative Thermodynamic Functions

Abstract

The solubility of cucurbit[5]uril in pure water and different concentration of hydrochloric acid aqueous solution(HCl:H 2 O = 10:110, 15:105, 20:100, 40:80) were investigated between 283.15 K and 323.15 K at atmospheric pressure by using the UV−vis spectrophotometer method. The solubility of CB[5] increased with the increasing of temperature, and a new phenomenon was found that the solubility of CB[5] increased with increasing acid concentration below 298 K and the solubility of CB[5] reduced with increasing acid concentration above 305 K. Thermodynamic functions (entropy and enthalpy of dissolution) for the CB[5] solutions were determined with the Van't Hoff equation, and the Gibbs free energy was also calculated.