karandikarmv
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calcium nitrite synthesis
i am trying to synthesis calcium nitrite.
i have taken calcium nitrate and tried to reduce it to calcium nitrite by using a reducing agent and also by thermal treatment. but i m not getting
the desired product .
how about using ammonium nitrate and lime? or using sodium nitrite and lime?
is there any other way to synthesis calcium nitrite...please let me know
[Edited on 5-9-2003 by karandikarmv]
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Mephisto
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I know for sure, that there is a synthesis described in the first volume of the second edition of „Handbook of Preparative Inorganic
Chemistry“ (G. Brauer, Academic Press, New York, 1963). It’s a standard reference work, so you can find it in the most libraries.
Reduction of calcium nitrate with lead didn’t work?
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karandikarmv
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Mephisto
i have checked in the book, but its not there
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Mephisto
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Sorry, I checked it too fast. So I messed up calcium nitrite with calcium nitride.
Maybe you’ve got an other process, which evolves nitrous fumes. You can lead the fumes through Ca(OH)2 and get a solution of calcium nitrite. A
nice way of recycling.
Sorry for the misguidance.
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karandikarmv
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Mephisto
is the following reaction possible?
Ca(NO3)2------ Ca(NO2)2 +O2
what is the temp. at which O2 will be evolved from Ca. nitrate?
the manufactures of Ca-nitrite claim it to be 500 deg.C
i have tried the above reaction and could get some Ca.nitrite, analysed as NO2 by spectro. method, but its only ~20% conversion from nitrate to
nitrite.
does recrystallisation required?
i am interested in 100%conversion of nitrate to nitrite.
i have also searched literature on the net and in library,but unable to get a complete paper.
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Mephisto
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There isn’t much source material about the synthesis of calcium nitrite. The conversion of calcium nitrate to the nitrite won’t work.
Here’s what I found:
‚Calcium nitrite decomposes to calcium oxide and a mixture of nitrogen monoxide and nitrogen dioxide at temperatures as low as 250 °C.‘
That’s the reason why calcium nitrate is directly converted to calcium oxide. ‚Thermal decomposition of calcium nitrate begins at 500 °C.
Ca(NO3)2 --> CaO + 2 NO2+ 1/2 O2 DH = +369 kJ/mol‘
A recrystallistion is possible, but I haven’t the exact solubility data. Only that:
‚The nitrite can be recovered as the tetrahydrate Ca(NO2)2 · 4H2O by concentration and cooling. This product has a lower solubility than
calcium nitrate tetrahydrate Ca(NO2)2· 4H2O.‘
The synthesis form Ca(OH)2 and nitrous gases yields to a technical product:
‚Calcium nitrite is formed when a mixture of gaseous nitrogen dioxide and nitrogen monoxide (OD < 50 %) is absorbed in a suspension of
calcium hydroxide. This process is used to clean up the final tail gases from low-pressure nitric acid plants when no demand exists for sodium nitrate
or sodium nitrite. The spent absorption liquor contains calcium nitrite and generally some calcium nitrate.‘
I hope, I could help a little bit. If you get access to a Beilstein database, you should find more.
Quoted from: [Ullmann's Encyclopedia of Industrial Chemistry, Sixth Edition, 2002 Electronic Release (c) Wiley-VCH. Weinheim. Germany.]
[Edited on 9-9-2003 by Mephisto]
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madscientist
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http://www.sciencemadness.org/talk/viewthread.php?tid=52
I weep at the sight of flaming acetic anhydride.
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karandikarmv
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Mephisto
today i got a little success,i hope that i have got some ca- nitrite, i am trying to analyse the nitrite in calcium nitrite
the spectrophotometric method for nitrite is only for low concentration of nitrite... so i am trying the volumetric method as per ASTM using potassium
permanganate and sodium oxalate
do u suggest any other method for high nitrite concentration?
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Mephisto
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Sorry, I haven’t much knowledge about volumetric analysis.
BTW, why are intersted in another method? The KMnO4 and oxalate method should be right.
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kingspaz
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would it not be possible to convert by recrystalisation?
like make some KNO2. make a hot saturated solution of Ca(NO3)2 and the KNO2 then allow to cool....KNO3 will crystalise out (i think, i have no
solubility data to hand a bad memory!) then you're left with Ca(NO2)2 in solution.
the unexamined life is not worth living to a human
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Sedit
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[moved]
[Edited on 16-3-2009 by Sedit]
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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Rosco Bodine
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Calcium Nitrite from Sodium Nitrite and Hydrated Lime
Quote: Originally posted by karandikarmv  | i am trying to synthesis calcium nitrite.
i have taken calcium nitrate and tried to reduce it to calcium nitrite by using a reducing agent and also by thermal treatment. but i m not getting
the desired product .
how about using ammonium nitrate and lime? or using sodium nitrite and lime?
is there any other way to synthesis calcium nitrite...please let me know
[Edited on 5-9-2003 by karandikarmv] |
Hopefully nobody was in a big hurry for an answer to your question 
Sodium Nitrite and Lime will work . See attached patent US4294813
Attachment: US4294813 Calcium Nitrite from Sodium Nitrite.pdf (103kB)
This file has been downloaded 819 times
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