Sciencemadness Discussion Board

Iodic acid from I2 and H2O2

outer_limits - 16-3-2020 at 11:22

Does anyone have experience using such path without chlorine or concentrated nitric acid?

Is this reaction even possible?


clearly_not_atara - 16-3-2020 at 11:39

An equilibrium is established, but under appropriate conditions IIRC it can be arranged to favor iodate. The attached file describes the reaction kinetics, which are complex. According to the half reactions:

2 IO3- + 2 H+ + 5 H2O2 >> I2 + 5 O2 + 6 H2O

I2 + 5 H2O2 >> 2 IO3- + 2 H+ + 4 H2O

it seems like low [H+], thus high pH, would favor a higher concentration of iodate at equilibrium. Note that the two half reactions are not inverses.

I have previously suggested using calcium acetate as the base, since it is not so alkaline as to destroy H2O2, and insoluble calcium iodate will precipitate so iodic acid can be recovered effectively by filtering Ca(IO3)2 and acidifying with sulfuric acid.

Attachment: schmitz2001.pdf (117kB)
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