Standard Molar Enthalpy of Formation of Morin Studied by Rotating-Bomb Combustion Calorimetry

Flavonols are plant pigments that are ubiquitous in nature. Morin and other related plant flavonols have come into recent prominence because of their usefulness as anticancer, anti- tumor, anti-AIDS, and other important therapeutic activities of significant potency and low systemic toxicity. The heat of com- bustion of morin (molecular formula, C15H10O7·H2O) in oxygen was measured by a rotating-bomb type combustion calorimeter, the standard molar enthalpy of combustion of morin at T = 298.15 K was determined to be △cHm~ (C15H10O7·H2O, s) =-(5 937.99 ±2.99) kJ·mol-1. The derived standard molar enthalpy of the for- mation of morin in solid powder state at T = 298.15 K, △fHm~ (C15H10O7·H2O, s), was - (1 682.12 ± 3.58) kJ·mol-1, which provide an accurate data of the stability of morin to the pharmacy and pharmacology.