No abstract

RuCl 3 can further catalyze the reaction between hexacyanoferrate(III) and iodide ions, which is already catalyzed by the hydrogen ions obtained from perchloric acid. Rate, when the reaction is catalyzed only by the hydrogen ions, was separated graphically from the rate when ruthenium(III) and H + ions both catalyze the reaction. Reactions studied separately in the presence as well as in the absence of RuCl 3 under similar conditions were found to follow second order kinetics w.r.t. [I ) ]. While the rate showed direct proportionality w.r.t. [Fe(CN) 6 ] 3) and [RuCl 3 ]. At low concentrations the reaction shows direct proportionality with respect to [H + ] which tends to become proportional to the square of hydrogen ion concentrations. External addition of [Fe(CN) 6 ] 4) ions retards the reaction velocity while change in ionic strength of the medium has no effect on the rate. With the help of the intercept of the catalyst graph, extent of the reaction, which takes place without adding ruthenium(III) was calculated and it was in accordance with the values obtained from the separately studied reaction in which only H + ions catalyze the reaction. It is proposed that ruthenium forms a complex, which slowly disproportionates into the rate-determining step. Arrhenius parameters at four different temperatures were also calculated.

No abstract

No abstract

The kinetics of the oxidation of 2-methyl cyclohexanone and cycloheptanone with Fe(CN) 6 3-catalyzed by RhCl 3 in alkaline medium was investigated at four temperatures. The rate follows direct proportionality with respect to lower concentrations of hexacyanoferrate(III) ion, but tends to become zero order at higher concentrations of the oxidant, while the reaction shows first-order kinetics with respect to hydroxide ion and cyclic ketone concentrations. The rate shows a peculiar nature with respect to RhCl 3 concentrations in that it increases with increase in catalyst at low catalyst concentrations but after reaching a maximum, further increase in concentration retards the rate. An increase in the ionic strength of the medium increases the rate, while increase in the Fe(CN) 6 4-concentration decreases the rate.