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Author: Subject: Substitute glacial acetid acid with 98% acetic acid?
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[*] posted on 22-11-2005 at 07:42
Substitute glacial acetid acid with 98% acetic acid?


How will it affect a particular reaction involving 30% H202 and glacial acetic acid, if I replace glacial acetic acid with acetic acid ~98% or maybe even 75%? I mean, the H202 contains water anyway, I just have to change the ratio between them is my thought...

any suggestions?

Ps. It's probably a stupid question, so just delete it if it's too stupid ;) Ds.
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[*] posted on 22-11-2005 at 09:25


Glacial Acetic Acid is ~98% Acetic Acid, Acetic Acid without water is Acetic Anhydride



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[*] posted on 22-11-2005 at 09:35


Actually, the glacial is 100% waterfree acetic acid (CH3COOH) and the acetic anhydride ((CH3CO)2O) is the anhydride of acetic acid.

98%-100% shouldn't make much difference.
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[*] posted on 22-11-2005 at 11:45


Well, it really is a stupid question. :P
If you are going to put 30% H2O2 together with acetic acid what difference can a little water make when you have 70% of water in the first reagent anyway?




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[*] posted on 22-11-2005 at 13:41


I just wanted to make sure that it really was a stupid question so I can forget about the glacial acetic acid and stick to the less expensive non-glacial acid :D
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[*] posted on 24-11-2005 at 00:37


....Glacial Acetic Acid is ~98% Acetic Acid....

, .....Acetic Acid without water is Acetic Anhydride Actually, the glacial is 100% waterfree acetic acid ............

Well, not to burst your bubbles or anything
;);););)but neither of these statements are correct according to ACS and this label on the bottle (GAA RA grade) has a water content of .02% (Karl Fischer).

Anhydrous reagents usually aren't truly and require special treatment to remove last traces of water for some purposes. Like this bottle of Absolute Ethanol which ain't.

Reagent Chemicals Ninth Edition
ACS Specifications - Official from January 1, 2000
© 2000 American Chemical Society

Acetic Acid, Glacial
REQUIREMENTS

Assay
99.7% CH3COOH


MAXIMUM ALLOWABLE
Color (APHA)
10
Dilution test
Passes test
Residue after evaporation
0.001%


Acetic anhydride [(CH3CO)2O]
0.01%
Chloride (Cl)
1 ppm
Sulfate (SO4)
1 ppm
Heavy metals (as Pb)
0.5 ppm
Iron (Fe)
0.2 ppm
Substances reducing dichromate
Passes test
Substances reducing permanganate
Passes test
Titrable base
0.0004 meq/g
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