Conc. Sulphuric Acid... Brown/red?
rav...@hotmail.com
Hi:
I just received a shipment of conc. sulphuric acid which is dark brown/red.
Is it normal? what may the cause for the coloration. This is the first time I
see it so deeply coloured.
Thanks for any suggestions.
Ravin
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Pharmacopoeia
No, it's not normal. Conc. sulphuric acid is colourless or almost
colourless. I guess the sulphuric acid is contaminated with dissolved
metals (probably from a container).
Pharmacopoeia
http://www.geocities.com/CapeCanaveral/Hangar/8106/
dlmyers
Sulfuric acid is typically colorless (or almost so). Any color is an
indication of contamination. Given the propensity of sulfuric to leach
metals I would not be surprised if one or more metal contanimants were in
your acid. The red/brown color is typical of chromium, but color can be
deceiving. I suggest you get some new acid and dispose of or return the
brown stuff.
rav...@hotmail.com wrote in article <6mtelc$qor$1...@nnrp1.dejanews.com>...
nos...@nospam.com
rav...@hotmail.com wrote:
>
> Hi:
>
> I just received a shipment of conc. sulphuric acid which is dark brown/red.
> see it so deeply coloured.
>
> Thanks for any suggestions.
>
> Ravin
>
> -----== Posted via Deja News, The Leader in Internet Discussion ==-----
> http://www.dejanews.com/ Now offering spam-free web-based newsreading
All of the conc H2SO4 that I have ever seen has been completely clear.
There is obviously some contamination happening there.
Ronald Thompson
Seems like it has some organic contamination in it. Definitely send it back.
Ron
Eric Lucas
Agreed that it's some sort of contamination, organic or inorganic. However, keep in mind the
fact that some of the contaminants (carbocations, in the case of organics) can be
exceptionally highly colored. As an example.... Stir a liter of good, clean hexane with conc.
H2SO4 for a few hours and observe the color of the H2SO4 layer. Levels of olefins completely
undetectable by NMR, IR and capillary GC (ppm levels, sometimes) can completely blacken the H2SO4
layer. The stuff you have may well be within spec, depending on what grade you ordered. I wouldn't
use it, but then if I were doing something where I cared about the color, I would order a grade that
has color specs on it.
Eric Lucas
Bruce Hamilton
In article <6mtelc$qor$1...@nnrp1.dejanews.com>
rav...@hotmail.com writes:
>I just received a shipment of conc. sulphuric acid which is dark brown/red.
>Is it normal? what may the cause for the coloration. This is the first time I
>see it so deeply coloured.
Concentrated sulphuric acid that is analytical reagent grade should always
be colourless, but technical grades can be dark brown - depending on purity.
If you have just ordered concentrated sulphuric acid of analytical grade,
you should return it to the supplier, as it probably is contaminated or is
incorrectly labelled.
Fuming sulphuric acid ( aka Oleum, and has 10-70% free SO3 ) can also range
from colourless to deep brown.
Bruce Hamilton
Lee Kennedy
Possibly COD reagent rather than Sulphuric Acid.
In article <6mtelc$qor$1...@nnrp1.dejanews.com>, rav...@hotmail.com wrote:
> Hi:
>
> I just received a shipment of conc. sulphuric acid which is dark brown/red.
> Is it normal? what may the cause for the coloration. This is the first time I
> see it so deeply coloured.
>
Tom Miller
I've seen reagent grade H2SO4 shipped in glass, red/brown/black coloration
from lid: structural cap is phenolic plastic with clear conical PE liner
insert, marginal deformation of insert permits contact of acid with P/F cap
--> color.
TMM
rav...@hotmail.com wrote in article <6mtelc$qor$1...@nnrp1.dejanews.com>...
SNUMBER6
>From: "dlmyers" <dlm...@kcc.com
>ulfuric acid is typically colorless (or almost so). Any color is an<BR>
>indication of contamination.
I have seen this effect with some types of paper contamination the H2SO4 ...
In the Village ....
I am not a number ... I am a free man !!!!
William R. Penrose
>Concentrated sulphuric acid that is analytical reagent grade should always
>be colourless, but technical grades can be dark brown - depending on purity.
If the acid is in a polyethylene bottle, it will eventually turn red or brown.
Also, the bottle will be weakened and the bottom will eventually fall out
(voice of experience). So return the stuff if you need it to be pure. If
not, make sure it was stored in glass.
If it is already in glass, chances are some organic contaminant got into it
and was carbonized.
Bill
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Mike Hall
rav...@hotmail.com wrote:
>
>
>Hi:
>
>I just received a shipment of conc. sulphuric acid which is dark brown/red.
>Is it normal? what may the cause for the coloration. This is the first time I
>see it so deeply coloured.
Ravin,
Its either contaminated or you mean/were sent nitric acid :-).
Mike
W
Hello:
If concentrated sulphuric acid has been contamined with organic matter
(e.g. cellulose from a little piece of paper), a strong dehydration will
take place, and fine carbon particles will be produced. This may be the
origin of the brown coloration.
Good luck
W