Kinetic bisulfite oxidation

Flowing Clock" Modification of the Experiment. In conventional clock reactions, it is difficult to obtain reliable results for reaction times of less than 20 or 30 s. Since much of modem chemical kinetics is concerned with reactions occurring on much faster time scales, it is worthwhile to introduce a modification of such experiments that makes use of a simple flow system to explore reaction times of the order of a few seconds or less. Both the iodide oxidation and formaldehyde-bisulfite reactions can be investigated in this way. 

The kinetics of aqueous dispersion polymerization differ very little from acrylonitrile bulk or emulsion polymerization. Redox initiation is normally used in commercial production of polymers for acrylic fibers. This type of initiator can generate free radicals in an aqueous medium efficiently at relatively low temperatures. The most common redox system consists of ammonium or potassium persulfate (oxidizer), sodium bisulfite (reducing agent), and ferric or ferrous iron (catalyst). This system gives the added benefit of supplying dye sites for the fiber. 

Both of these are distal groups, but their identity is unknown. Depending upon the substrate, either acid or base catalysis can occur in HRP-I reactions. For HRP-II reactions only acid catalysis is important for substrates which are oxidized with difficulty, protonation of the proximal imidazole group in the fifth coordination position of the Fe( V) of HRP-II is important. (The pK is Ol) The amount of this hyperreactive form cannot be detected spectroscopically at physiological pH, but it is the only kinetically active species for inorganic substrates such as iodide, nitrite or bisulfite. ... 

PBI Systenio Two kinetic processes are involved the reduction of persulfate by iron (II) and the oxidation of bisulfite by iron (III) as shown below with their corresponding specific rate constants, kj and k2. 

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