8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

P2.42Tue 611:23-14:00Compensation effect in thermodynamics ofhydroperoxides solutionsIrina Kolyadko, 1 Dina Kamalova, 2 Alexandr Remizov, 1 and Roman Skochilov 11 Kazan State Technological University, 68, K. Marx St. , 420015, Kazan, RussianFederation2 Kazan University, Kazan, Russian FederationDecay of hydroperoxides is one of the major stages of liquid-phase oxidation of hydrocarbons.Association and self-association are of important significance when hydroperoxides decay in solutions.In this work we studied the relationship between the enthalpy and entropy changes in thermodynamicsof hydroperoxides solutions. Compensation effect has been found in an extremelywide range of fields. It has also been established for the reactions such as hydrogen bonding andconformational transitions in various solvents. Free energy changes ∆G i of the i-th reaction ofthe forming of associates or the forming of conformations are equal to ∆G i = ∆H i − T∆S i ,where ∆H i and ∆S i are the enthalpy and entropy changes of the i-th reaction, consequently. Ifthere is a linear relationship between the enthalpy ∆H i and entropy ∆S i changes of a series ofsimilar reactions, the compensation effect is true, i. e. ∆H i = a + α∆S i , where a and α areconstants. Thus, ∆H i and ∆S i values changes in the same direction when going from one reactionto another. As a result, ∆G i value decreases due to the enthalpy change ∆H i and increases due tothe entropy change ∆S i . Using IR spectroscopy and the factor analysis technique we investigatedthe temperature dependencies of self-associates equilibrium constants of cumyl hydroperoxideC 6 H 5 (CH 3 )COOH, tertiary butyl hydroperoxide (CH 3 ) 3 COOH and 3-phenylmethyl hydroperoxide(C 6 H 5 ) 3 COOH in different solvents. Enthalpy, entropy and free energy of reaction formingof self- and heteroassociates have been determined. It has been shown that there is the compensationeffect in thermodynamics of the self- and heteroassociates of the hydroperoxides. This workwas supported by RFBR (Project 09-03-00225-a).42