Formatik - 18-4-2009 at 22:59
Gmelin cites a reference (Rouquette, C.r. 154 [1912] 448) that claims Na2S2O9 results by the addition of H2O2 onto a conc. soln. of NaHSO4. I remember
a while back going on a wild goose chase for this purported Na2S2O9, only to find Per-acids and Their Salts, which points out earlier ideas
concerning the formula of Caro's acid, as being either H2SO5 or H2S2O9, which was many years ago, now we know Caro's acid to be H2SO5. So H2O2 and
NaHSO4 should be simple enough to get an aq. solution of the sodium peroxymonosulfate.
Now, DE1080083 mentions that despite having 2 hydrogen atoms, only one of the atoms on H2SO5 is readily replaced by a metal, so that the formula of
the sodium salt is thus given as NaHSO5. NaHSO5 has 58.8% O2, compared to Na2S2O8 which has 53.8% O2. Not bad, but then also, Na2S2O8 is also
significantly more difficult to form, requiring a complicated electrolysis or double-decomposition with other peroxydisulfates. Anyways, I suspect
then the interaction is a then: NaHSO4 + H2O2 = NaHSO5 + H2O. So is that all there's to it?
S.C. Wack - 19-4-2009 at 06:28
That may depend on concentration.
http://v3.espacenet.com/publicationDetails/originalDocument?...
Formatik - 19-4-2009 at 12:11
According to that useful patent, the H2O2 must at least be 60% to get even a minute conversion to monopersulfate. Likely then Rouquette's H2O2 must
have also been very high percentage.