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Topic: Thermogravimetric Analysis Standard - Decomposition?  (Read 245 times)

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Offline One Inch Ash

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Thermogravimetric Analysis Standard - Decomposition?
« on: November 16, 2020, 07:29:10 PM »
Hi guys.
I'm analyzing the thermogram of Disodium Tartrate Dihydrate. After getting rid of the water, there's only DT left. What does the Disodium Tartrate decompose to?

I'm referring to the second plateau after 280 celsius. Thanks guys!

Offline AWK

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Re: Thermogravimetric Analysis Standard - Decomposition?
« Reply #1 on: November 17, 2020, 12:02:36 AM »
Search the internet first.
AWK

Offline One Inch Ash

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Re: Thermogravimetric Analysis Standard - Decomposition?
« Reply #2 on: November 17, 2020, 04:31:16 PM »
Search the internet first.

Oh thank you so much! I truly did not think to try to search the internet before coming here at all....
 ::)    (I was being sarcastic if you didn't pick it up)

After NOT being able to find anything using keywords "Disodium Tartrate Dihydrate", "Disodium Tartrate", "TGA", "decomposition", and "+ heat", I found Figure 4 of this article a few hours after posting here.

G. Panzarasa, “Rediscovering Pyrotartaric Acid: A Chemical Interpretation of the Volatile Salt of Tartar,” Bull. Hist. Chem., 2015, 40, 1-8.

Such a helpful answer in this forum. Not.

Offline jeffmoonchop

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Re: Thermogravimetric Analysis Standard - Decomposition?
« Reply #3 on: November 17, 2020, 05:26:33 PM »
Hard to tell, but it looks like around a third of the mass comes off (after water is gone). Are there any degradants you can make which might add up to a third of the remaining mass?

Offline Corribus

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Re: Thermogravimetric Analysis Standard - Decomposition?
« Reply #4 on: November 17, 2020, 06:07:11 PM »
Anything with a carboxylic acid is prone to decompose via liberation of carbon dioxide. Tartaric acid/tartarate has a lot of mass bound out up in carboxylic acid groups. My guess would be that  thermal degradation occurs first through liberation of carbon dioxide, which explains the significant mass loss at fairly low temperature. CO2 production of course is common during combustion of any organic molecule, but oxidation isn't really necessary when you've got a CO2 group there just dying to detach. This is a fairly common observation in TGA. The slow decline after 280 C or so is probably thermal degradation of whatever organic is left after loss of the CO2 groups, probably oxidation also to CO2 if you've got oxygen present. The residue is probably primarily sodium based, plus possibly some carbon depending on how oxygen rich your environment was.

That'd be my starting point anyway. With TGA it's hard to conclude much absolutely about decomposition chemistry without a supplementary analysis method.

Btw - at Chemical Forums we don't like to just hand out answers. If you read the forum rules, as you were directed when you made an account,, you'll see that you're supposed to describe your own thinking or show your work before you receive help. This is why you didn't get much of a helpful response.
What men are poets who can speak of Jupiter if he were like a man, but if he is an immense spinning sphere of methane and ammonia must be silent?  - Richard P. Feynman

Offline AWK

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Re: Thermogravimetric Analysis Standard - Decomposition?
« Reply #5 on: November 17, 2020, 09:29:34 PM »
Search the internet first.

Oh thank you so much! I truly did not think to try to search the internet before coming here at all....
 ::)    (I was being sarcastic if you didn't pick it up)

After NOT being able to find anything using keywords "Disodium Tartrate Dihydrate", "Disodium Tartrate", "TGA", "decomposition", and "+ heat", I found Figure 4 of this article a few hours after posting here.

G. Panzarasa, “Rediscovering Pyrotartaric Acid: A Chemical Interpretation of the Volatile Salt of Tartar,” Bull. Hist. Chem., 2015, 40, 1-8.

Such a helpful answer in this forum. Not.
Your internet research skills are "amazing". Google search of:
thermal decomposition of sodium tartrate
gives access to the first two pages of the publication discussing the thermogravimetry of disodium and dipotassium tartrates.
AWK

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