화학공학소재연구정보센터
Journal of Physical Chemistry B, Vol.102, No.21, 4247-4252, 1998
Catalytic reduction of alpha,omega-dihaloalkanes, X(CH2)(m)X (X = Cl, Br, or I and m = 2-8), by electrochemically generated C-70(n-) (n = 2 or 3) in benzonitrile solutions
The first report on the homogeneous electrocatalytic reduction of halogenated alkanes by C-70 anions is presented. Cyclic voltammetry (CV) measurements indicate that C-70(n-) (n = 2 or 3), electrochemically generated in 0.1 M (TBA)PF6, benzonitrile, catalyzes the dehalogenation of alpha,omega-dihaloalkanes, X(CH2)(m)X (X = Cl, Br, or I and m = 2-8). Values of the second-order rate constant, k, for the electrocatalytic dehalogenation of the alpha,omega-dihaloalkanes by the C-70(n-) anions were determined by using the rotating-disk electrode (RDE) voltammetry under pseudo-first-order conditions with respect to the alpha,omega-dihaloalkanes. In accordance with Saveant's theory of dissociative reduction, the k values increase in the order Cl < Br < I for the investigated 1,2-dihaloethanes. The k values also decrease with the number of carbon atoms of the alkyl chain for the investigated series of alpha,omega-diiodoalkanes. The calculated k values for the C-70(n-) (n = 2 or 3) catalysts are generally smaller than those for the C-60(n-) (n = 2 or 3) catalysts. Unlike the C-60(n-) electrocatalysis, reported earlier to be accompanied by a chemical reaction between C-60(n-) and certain alpha,omega-diiodoalkanes yielding alkyl adducts of C-60, no reaction between C-70(n-) (n = 2 or 3) and the alpha,omega-diiodoalkanes leading to alkylated C-70 was observed on the voltammetry time scale.