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Kinetic and thermodynamic properties of the aerial oxidation of hydroquinone in developer solutions
Author(s) -
Asadollah Nasehzadeh,
Hossain Resa, Sayyed,
Azita Khosravan
Publication year - 2000
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.20000180304
Subject(s) - hydroquinone , chemistry , semiquinone , enthalpy , activation energy , kinetics , kinetic energy , thermodynamics , redox , inorganic chemistry , organic chemistry , physics , quantum mechanics
The aerial oxidation kinetics of hydroquinone in a freshly prepared developer solution at different temperatures and pHs has been studied. The activation parameters, E a , Δ G # , Δ S # , Δ H # and enthalpy of formation of activated complex, Δ H 0 f (X # ), are determined. The large negative value of free energy of activation Δ G # proves that hydroquinone extremely tends to be oxidized by air at optimum temperature (20°C and optimum pH (10.5) and converts to the activated complex semiquinone. It was also found that if the pH of the developer solution is increased from 9.3 to 10.5 the reaction rate will increase by a factor of 2.