US EPA

8349251 

Journal Article 

Kinetic-mechanistic study of Mn11 catalyzed periodate oxidation of 3,5-xylidine 

Kaushik, RD; Singh, J; Agarwal, R; Kumari, E 

2016 

Yes 

Journal of the Indian Chemical Society
ISSN: 0019-4522 

93 

1 

85-91 

English 

The kinetics of the Mn11 catalyzed periodate oxidation of 3,5-xylidine (3,5-DMA) in acetone-water medium has been followed by monitoring the increase in the absorbance of reaction intermediate. Reaction is first order in reactants and catalyst each. A decrease in dielectric constant of the medium results in decrease in the rate of reaction. Free radical scavengers do not affect the reaction rate. One mol of 3,5-DMA reacts with two moles of periodate during the initial part of reaction. The main reaction product is 2,6-dimethyl-/?-benzoquinone. The values of thermodynamic parameters are : AE = 22.98 kJ mol1, A = 1.10 x 109 dm3 mol1 s1, AS0 = -151.44 J mol1 K1, AG= 67.42 kJ mol1 and AH = 20.40 kJ mol1. Under pseudo-first order conditions, [3,5-DMA], the rate law is given by :l/cat = (K2lkK3K4 [H + ]) + {(tfw + KhK2)JkK3K4KJ + Kh[H+]/kK3K4Kw where kK3K4 is the empirical composite rate constant, Kw is ionic product of water, K2 is acid dissociation constant of H4I06~ and Kh is base dissociation constant of 3,5-DMA. In agreement with the rate law the l/cat versus [H + ] plot passes through the minimum. Detailed molecular mechanism is given. © 2016 Scientific Publishers. All Rights Reserved. 

2,6-diniethyl-/benzoquinone; 3,5-xylidine; Kinetics; Periodate