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What is Glacial acetic acid


I know what acetic acid is, but what is ‘glacial acetic acid’?


Glacial Acetic Acid is referred to as “Stop Bath” in photography
developing. Its used to stop the developing process in film and
print making.

I know what acetic acid is, but what is 'glacial acetic acid'? 

“glacial” means the fully concentrated, almost fuming, form.
Acetic acid can be just vinegar, which is only 5%. Good in a salad,
and tastes nice. glacial acetic acid is something you need to handle
with considerable care. Gloves, mask, ventilation, and all that
jazz. Same as any other concentrated acid (except perhaps
hydrofluoric, which requires even MORE care.)


I know what acetic acid is, but what is 'glacial acetic acid'? 

G’day Janet Berg; Glacial is concentrated acetic acid. It can
only be called ‘glacial’ if it solidifies like ice at 15C. It is
so concentrated that the glacial acid will burn flesh easily - and
painfully. If you want to check a sample of acid place it in a
refrigerator (NOT a freezer ) with a thermometer and see what
temperature it freezer at… Be careful with it

Cheers for now,
John Burgess; @John_Burgess2 of Mapua, Nelson NZ


Pure acetic acid was first isolated about 1700 by the distillation
of vinegar. When pure, acetic acid is a clear, colorless liquid with
a sharp, irritating odor of vinegar. In poorly heated laboratories,
the acid was oftentimes found frozen inside its container because its
freezing point is only slightly below room temperature at 16.7B0C.
The term glacial (ice-like) came to be applied to the pure acid in
either its solid or liquid state. Glacial acetic acid boils at
118B0C, and has a density of 1.049 g/mL at 25B0C. It is flammable
with a flash point of 39B0C. Through hydrogen-bonding interactions,
acetic acid is miscible (mixable) in all proportions with water,
ethyl alcohol, and diethyl ether. Pure or concentrated solutions of
acetic acid are very corrosive and can cause painful burns. Aqueous
solutions of acetic acid freeze at temperatures below the freezing
point of water."

Tony Konrath
Key West Florida 33040

I know what acetic acid is, but what is 'glacial acetic acid'? 

Howdy Janet, I hate to reply knowing that John and others will have
more authoritative answers, but, having been a hobby B&W
photographer in the past, GAA is often diluted to make a 'stop’
bath. When I asked my mentor at the time about the unusual name he
gave me an anwser that seemed a little like a myth (something about
climbers mistaking it for water ice). I have since looked it up once
and it seems it’s resemblance to water ice at (quite low) room temp.
(perhaps labs in europe were unheated in the past?) That is, it
looks like ice when solid. There were 2-3 other chemicals with the
same descriptive term.

1 Lucky Texan

 I know what acetic acid is, but what is 'glacial acetic acid'? 

Glacial acetic acid is pure (undiluted) acetic acid. Be careful with
it. It can “burn” your fingers, the skin turns yellow and hard. Acetic
acid is usually used in some diluted form.



Hello Janet, My greeting to you in my last post disappeared as did my
name at the end. Gremlins? I think it has more to do with this Mac
G4 being new and we still have a lot to learn. I’ll try to get it
right this time.

Glacial acetic acid is pure acetic acid, usually 99.5 percent pure
(17.5 molar). It is a clear colorless liquid which freezes on a
cold day (f.p. = 16.6 deg. C) to give an ice-like solid. The icy
appearance gave it the name “glacial”. Acetic acid (also named
ethanoic acid, CH3COOH) boils at 117.9 deg. C and has a flash point
of 40 deg. C (closed cup). The density is 1.0446 grams per cc. The
acid has a very sharp nasal membrane ripping odor. It is quite
corrosive, especially on skin. Like most of the concentrated acids,
it liberates heat on dilution with water, but it is not nearly as
exothermic as concentrated sulfuric acid.

Acetic acid (Ethanoic acid) is prepared in small amounts by
fermentation processes (vinegars - about 5 percent acetic acid).
The large quantity used in industry is prepared by the hydration of
ethylene over an acid catalyst to yield ethyl alcohol. The ethyl
alcohol is oxidized to acetaldehde over a silver catalyst and the
acetaldehyde is then oxidized to acetic acid. Another process
oxidizes ethylene directly to acetaldehyde using a palladium/Cu2O2
catalyst in hydrochloric acid. The process looks like this (all of
these steps are carried out in the vapor phase at high temperatures
and pressures):

(1) H2O + CH2=CH2 over H3PO4 on celetom yields CH3-CH2OH

(2) Then: CH3-CH2OH + O2 over Ag on alumina yields CH3-CHO

(3) Then: CH3-CHO + O2 with Mn /Co acetates yields CH3-COOH

The acid is concentrated and purified by fractional distillation.
That is probably more than you wanted to know about glacial acetic
acid. But, more has to be better than the bare minimum

Captain Blood
"Marlinespike Seamanship in Precious Metals"

    Glacial Acetic Acid is referred to as "Stop Bath" in
photography developing.  Its used to stop the developing process in
film and print making. 

Uh Uh. Close, though. Acetic acid is used as a stop bath, but it is
derfinitely quite dilute, not glacial (i.e. concentrated)


I know what acetic acid is, but what is 'glacial acetic acid'? 

Janet, it’s another name for concentrated (i.e. pure) acetic acid.
It has that name because it would commonly solidify in the bottle
during the winter in labs, in “the old days”.

Kevin (NW England, UK)