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Author: Subject: Thermally Decompose Compounds in a Furnace - For how long to remove Oxygen?
LuckyWinner
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[*] posted on 24-11-2020 at 13:06
Thermally Decompose Compounds in a Furnace - For how long to remove Oxygen?


I want to thermally decompose sodium iodate to sodium iodide
in a DIY Kanthal furnace.

both of these compounds are mixed together and will be added together
into the furnace.

it can reach the melting point temperature of sodium iodate at 425C.

But for how long would you keep this inside the furnace at ~450C to make
sure the reaction is complete?

Put the sodium iodate + sodium iodide crystals together
into a porcellain vase inside the furnace and slowly heat it up.

I guess it will melt once it gets to 425C and be hard to remove from the vase.
so simply add water to remove the 'crust' from the porcellain
and recrystallize?


http://www.sciencemadness.org/talk/viewthread.php?tid=17635#...


Quote:

Better to get rid of the iodate thermally, the recrystallise the whole batch to obtain nice, 100 % water soluble product, iodine free....

That's the easiest way, and it requires 425 C ....

Iodate is removed by heating strongly: NaIO3 === > NaI + 3/2 O2. Like heating chlorate...
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chemship1978
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[*] posted on 24-11-2020 at 13:39


Iodate starts decomposing quickly after melting. You could judge the doneness by whether it's still bubbling oxygen out or not.
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LuckyWinner
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[*] posted on 24-11-2020 at 14:02


Quote: Originally posted by chemship1978  
Iodate starts decomposing quickly after melting. You could judge the doneness by whether it's still bubbling oxygen out or not.


ok, but if it can not be checked that easily,
you think with 1 hour at 450C its going to be fully converted?
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B(a)P
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[*] posted on 24-11-2020 at 17:48


I can't comment on your proposed approach to decomposition, but for recrystallisation you might consider ethanol.
Sodium iodate is insoluble in ethanol whereas sodium iodide is readily soluble in ethanol.
Also double check that 450 C is a high enough temperature. I can't find a reliable source on hand, but this web site has it at 500 C

edit fixed the link
http://chemister.ru/Database/properties-en.php?dbid=1&id...

[Edited on 25-11-2020 by B(a)P]
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LuckyWinner
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[*] posted on 25-11-2020 at 01:55


Quote: Originally posted by B(a)P  
I can't comment on your proposed approach to decomposition, but for recrystallisation you might consider ethanol.
Sodium iodate is insoluble in ethanol whereas sodium iodide is readily soluble in ethanol.
Also double check that 450 C is a high enough temperature. I can't find a reliable source on hand, but this web site has it at 500 C

edit fixed the link
http://chemister.ru/Database/properties-en.php?dbid=1&id...

[Edited on 25-11-2020 by B(a)P]


I tried to separate the NaI from NaIO3 by using NaI's soluability in anhydrous acetone and ethanol.
But I could hardly dissolve NaI in these 2 solvents under mag stirring and heating...

maybe a majority of NaIO3 is produced under specific conditions.
I mixed and heated NaOh with Iodine.
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[*] posted on 25-11-2020 at 02:03


Quote: Originally posted by LuckyWinner  


I tried to separate the NaI from NaIO3 by using NaI's soluability in anhydrous acetone and ethanol.
But I could hardly dissolve NaI in these 2 solvents under mag stirring and heating...



NaI becomes less soluble in ethanol at higher temperatures
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LuckyWinner
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[*] posted on 26-11-2020 at 08:33


Quote: Originally posted by B(a)P  
Quote: Originally posted by LuckyWinner  


I tried to separate the NaI from NaIO3 by using NaI's soluability in anhydrous acetone and ethanol.
But I could hardly dissolve NaI in these 2 solvents under mag stirring and heating...



NaI becomes less soluble in ethanol at higher temperatures


Solubility
--------------
I tried dissolving it in cold/ room temp ethanol and It also barely dissolved.
was mag stirred for 1 hour and distilled off.

NaI does not seem to be as soluble in acetone and ethanol as noted in the literature.
or what am I doing wrong?

https://pubs.acs.org/doi/pdfplus/10.1021/ja01417a015
Macy, R., & Thomas, E. W. (1926). THE SYSTEM: SODIUM IODIDE-ACETONE-WATER. Journal of the American Chemical Society, 48(6), 1547–1550. doi:10.1021/ja01417a015


Fig. 1.-Solubility of sodium iodide in acetone.

The highest soluability is at a temperature of 25C
70.6% Acetone
29.4% NaI
(% by weight )

that means
70.6g of acetone can dissolve 29.4g of NaI
acetone density is 0.791 g/mL =/ 70.6g = 89.25 ml


other source says

Solubility (NaI g/100 g of solvent):
http://chemister.ru/Database/properties-en.php?id=760
acetone: 39.9 (25°C) [Ref.]








furnace:
----------
the NaI and NaIO3 seemed to be melted down in the furnace successfully,
temp went up to 650C and stayed between 500 C and 650 C for over 1 hour.
was a solid rock after cooldown.

to purify this, dissolve in water and filter through a filter then evaporate.
since dust from the furnace went inside once taken out.

how would one neutralize residues of NaOh from this NaI?
adding HCL will also attack the NaI and release iodine...

I want to do a finkelstein with the NaI...
if NaOh is present the acetone will self aldol react...

[Edited on 26-11-2020 by LuckyWinner]
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