Kinetics of the addition reaction of triphenylphosphine to para-benzoquinone in 1,2-dichloroethane as solvent was studied. Initial rate method was used to determine the order of the reaction with respect to the reactants. Pseudo-first-order method was also used to calculate the rate constant. This reaction was monitored by UV-vis spectrophotometry at 520 nm by variable time method. On the basis of the obtained results, the Arrhenius equation of this reaction was obtained:The activation parameters, E a , H # , G # , and S # at 300 K were 5. 701, 6.294, 19.958 kcal mol −1 and −45.853 cal mol −1 K −1 , respectively. This reaction is first and second order with respect to triphenylphosphine and para-benzoquinone, respectively. C

This work reports the results of a kinetic and mechanistic investigations of the addition reaction of triphenylphosphine to para-naphtoquinone in 1,2-dichloromethane as solvent. The order of reaction with respect to the reactants was determined using initial rate method, and the rate constant was obtained on the basis of pseudo-first-order method. Variable time method using Uv-Vis spectrophotometry (at 400 nm) was utilized for monitoring this addition reaction, for which the following Arrhenius equation was obtained: log k = 9.14 − 13.63 2.303RTThe resulting activation parameters E a , H # , G # , and S # at 300 K were 13.63, 14.42, 18.75 kcal mol −1 , and −14.54 cal mol −1 K −1 , respectively. The results suggest that the reaction is first order with respect to both triphenylphosphine and para-naphthoquinone.

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