Jor
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periodic acid synthesis
I have always wanted to make some periodic acid.
First you need Na3H2IO6, wich is a trisodium-salt of orthoperiodic acid. This is easily prepared by oxidising iodine with sodium chlorate to sodium
iodate, followed by oxidation with chlorine in alkaline solution. Woelen has made a great web page on the oxidation of KIO3 to KIO4.
The salt Na3H2IO6 has to be dissolved in water with some conc. HNO3 added. Next Ba(NO3)2 has to be added and the solution boiled. It is then
neutralized with Ba(OH)2. One can also dissolve KIO4 in KOH and add barium nitrate.
Now my question is, does anyone know if I can replace the barium nitrate with strontium nitrate? Ofcourse I can try it, but not yet, as it is way too
cold. So I thought, maybe anyone has experience with this?
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not_important
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Your procedure doesn't match any I'm familiar with, and seems slightly incomplete.
Not knowing more, I'd say "maybe", the periodates are odd ducks. You'd need to check the solubilities involved; if your goal is the free acid
produced by reaction with H2SO4 check the relative solubilities of the two sulfates as well.
[Edited on 12-1-2009 by not_important]
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UnintentionalChaos
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If the reaction is completed with H2SO4 acting on an alkaline earth periodate, then strontium will be a fine substitute, assuming the strontium and
barium periodate have similar solubilities. Strontium sulfate is somewhere between calcium sulfate and barium sulfate in solubility, which is to say,
negligably soluble.
[Edited on 1-12-09 by UnintentionalChaos]
Department of Redundancy Department - Now with paperwork!
'In organic synthesis, we call decomposition products "crap", however this is not a IUPAC approved nomenclature.' -Nicodem
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not_important
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SrSO4 Solubility in water 0.0135 g/100 ml (25°C)
BaSO4 Solubility in water 0.000115 g/100 ml (18°C)
low, but still 100x that of barium, plus it has an annoying tendency to be a bit more soluble in dilute acids or even in neutral salt solutions. I
was rather peeved when a double decomposition that precipitated SrSO4 resulted in a product that had extremely strong strontium lines in its spectrum.
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Jor
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Ok thanks.
I think I'll buy some barium nitrate then. 250g will set me back about 10 euro, including shipping.
When I do the synthesis, I will post pictures. It will no be very soon though.
[Edited on 12-1-2009 by Jor]
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chloric1
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| Quote: | Originally posted by not_important
SrSO4 Solubility in water 0.0135 g/100 ml (25°C)
BaSO4 Solubility in water 0.000115 g/100 ml (18°C)
low, but still 100x that of barium, plus it has an annoying tendency to be a bit more soluble in dilute acids or even in neutral salt solutions. I
was rather peeved when a double decomposition that precipitated SrSO4 resulted in a product that had extremely strong strontium lines in its spectrum.
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Damn that sucks! I have seen in a patent for removing barium from strontium salts. They use strontium sulfate to precipitate in an ALKALINE
solution. Vigorous stirring and prolonged boiling is involved. IRC it starts off acidic to hep increase the solubility of the reactant SrSO then
alkalized with Sr(OH)2 after the bulk of the barium is removed.
I would retry your metasynthesis, this time focusing on pH variations to force the desired equilibriums.
Might I ask what was your metasynthesis?
Fellow molecular manipulator
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