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MadHatter
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Roebic
Bromic Acid, is that the Roebic Drain Flow brand of sulphuric acid you're describing ? Apparently,
the carbon is thrown in as some kind of warning indicator to a novice. Personally, I never
worried about that shit. Made good vacuum distilled nitric acid in any event. The carbon
was more of a pain-in-the-ass than anything else. Basic filtering through glass wool
was more than enough for my needs. This was until I discovered ROOTO through my local
Ace Hardware. I'll never go back to Roebic ! If you want good sulphuric acid OTC, that's
the way to go ! BTW, Misty is an excellent brand also but harder to get.
From opening of NCIS New Orleans - It goes a BOOM ! BOOM ! BOOM ! MUHAHAHAHAHAHAHA !
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Pyridinium
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BromicAcid, I have also noticed during recycling H2SO4 (contaminated with organic matter and metal ions), the conc. acid by itself will carbonize the
organics and oxidize them after protracted heating at around 220-240 C. SO2 and water come off, as well as CO2 and H2SO4 fumes. It takes about a
day of heating to make the acid turn from murky brown-black to pale straw-yellow.
I know it's a great deal of work and not really cost effective. Also dangerous.
side note... Oxidizers...  You and the other regulars on this forum obviously
know not to put permanganates or chlorates in the acid to oxidize the contaminants, but some occasional readers might not. So we might as well tell
them now: DON'T use permanganates or chlorates for this.
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neutrino
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Perchlorates also wouldn't be the best of ideas here.
In response to a previous question, the peroxide works by forming caro's acid (H<sub>2</sub>SO<sub>5</sub> , which then oxidizes any organic matter present.
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Organikum
resurrected
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A european brand of drain cleaner "STURA FACILE" says it is 66°Be H2SO4 what would be 94% to 98%. It has a reddish tint and foams when used
as in in drying bottles or similar.
On heating to the boiling point it first turns black - after prolonged heating it turns almost perfectly clear.
My experieneces with battery acid 38% vary. Some stayed perfectly clear upon concentration and some got greenish - probably from iron salts present
from storage in iron vessels.
/ORG
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ADP
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Hmm I wonder what H2SO5 + KNO3 would yield. Or if the H2SO5 would just decomp and make Nitric acid and a salt.
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Scratch-
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I was wondering something similar, I was wondering if H<sub>2</sub>SO<sub>5</sub> could be stabilized by adding NaOH or other
strong base?
H<sub>2</sub>SO<sub>5</sub> + 2 NaOH => Na<sub>2</sub>SO<sub>5</sub> + 2 H<sub>2</sub>O
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BromicAcid
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Persulfates are fairly stable salts, ammonium persulfate being somewhat widely avalible for etching circuits.
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neutrino
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I think SO<sub>5</sub><sup>2-</sup> is more accurately called peroxysulfate. Persulfate (the etching ion) is
S<sub>2</sub>O<sub>8</sub><sup>2-</sup>.
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Pyridinium
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I'm pretty sure one of the preparations for Caro's acid (peroxymonosulfuric acid) involves reacting persulfate (peroxydisulfate) with H2SO4.
Might've been mentioned in another thread, sorry if it's redundant.
I think in the cold (-80 C) you can get it to form crystals. They are stable as long as the temp doesn't rise...
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Bonome
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Purify sulfuric acid
Is it possible to remove the impurities of Sulfuric Drain Opener? I don't found any topics about the question and I think it would be great if we can
find a solution to purify Drain Opener acid because it's inexpensive and personally I'm in canada and I really don't know how to obtain pure sulfuric
acid. My idea was to Distill at very high temperature to break the acid to H2O and SO3 but the difference in temperature between the cold condenser
and vapour will certainly brake it so maybe you have more idea?
There is no knowledge that is not power.
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bereal511
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IIRC, there was a thread a while ago that discussed the use of hydrogen peroxide by slowly adding it to sulfuric acid drain cleaner and heating the
solution gently, withsuccess in getting rid of most of the organics.
As an adolescent I aspired to lasting fame, I craved factual certainty, and I thirsted for a meaningful vision of human life -- so I became a
scientist. This is like becoming an archbishop so you can meet girls.
-- Matt Cartmill
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BromicAcid
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Yes there are other topics on this around here though I am not sure about what they are titled. Distillation will work, giving you the azeotrope of
something in the neighborhood of 96% sulfuric acid. The peroxide method that bereal mentioned above noteably lightens darker sulfuric acid though
that doesn't say anything for any cations/anions that may be present, just some of the organics. Anyway, there are other threads.
If you haven't found out yet our search engine here is somewhat shoddy so I recomend going to google and searching with the modifier
site:sciencemadness.org
which will give results from this site. There are a few threads covering this from various aspects so good luck.
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Bonome
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Thanks, I found the topics.
titled 'cleaning sulfuric acid'
sorry for this double post maybe an administrator can delete mine?
There is no knowledge that is not power.
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chemrox
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I made pirhana from drain cleaner and 30% H2O2. It cleared immediately on adding the peroxide. Ala Vogel 100% sulfuric is made by adding oleum
(fuming acid) to the 98% which is obtained by distillation. I.e distill the drain cleaner and you've got reagent acid.
"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
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Pulverulescent
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The first time I boiled battery acid, I got a brown acid, which became colourless on prolonged heating. As the colour vanished, small bubbles appeared
and a small white precipitate formed.
The precipitate was silica and the colour was caused by dissolved carbon which was subsequently oxidised by hot H2S04.
Silicon carbide, it seems, had been added to the acid to prevent the formation of long lead crystals on the battery plates, which could short the
cells.
If the drain-cleaner contaminant was organic it would be fully oxidised by strong heating.
Adding peroxide is a waste since hot H2S04 itself, is a good oxidiser.
I've thought of getting an old-type retort and distilling draincleaner but there's a chance the contaminent would come over with the acid and I don't
know if borosilicate would withstand heating to 337*C. . .
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MagicJigPipe
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"and I don't know if borosilicate would withstand heating to 337*C. . . "
It most certainly will. I boil sulfuric acid all the time and have never had problems. Never. Except for the very first time I did it. I didn't
realize how hot the H2SO4 was (even nearly 45min after boiling) and poured it in a HDPE container. It melted and sprung a leak while I was holding it
so I panicked, dropped it and hot sulfuric acid went everywhere. "Fuckin flying shitballs!", I exclaimed as I deficated in my pants. Just kidding
about the defication.
What's funny is at the time, my parents, knowing nothing about chemistry or chemicals said, "Your jeans look like you spilled a bunch of battery acid
on them!"
Anyway, I think I may have read about this here somewhere but has anyone attempted distillation of H2SO4? In theory, this should yield extremely pure
acid even from drain cleaner. As far as dissolved solids go it should be like reagent grade as someone mentioned earlier.
I always wanted to try it but I don't want my glassware to break. I'm theorizing about a decent way to heat the neck of the flask so that no water
drips into the acid. Any ideas other than a topside mantle?
"There must be no barriers to freedom of inquiry ... There is no place for dogma in science. The scientist is free, and must be free to ask any
question, to doubt any assertion, to seek for any evidence, to correct any errors. ... We know that the only way to avoid error is to detect it and
that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think,
free to think what they will, freedom can never be lost, and science can never regress." -J. Robert Oppenheimer
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-jeffB
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I'm working up my nerve to try distilling some drain cleaner. In the past, I've distilled lower-boiling liquids in an all-glass setup where I wrapped
Teflon tape around the male connectors during assembly. It looks like the upper temperature limit for standard Teflon tape is somewhere around 300C.
How bad an idea would it be to use standard "plumber's" Teflon tape in this temperature regime?
I'm thinking a water-cooled condenser is also a bad idea. I have a straight tube with 24/40 connectors on each end that's maybe 60cm long. If I use
that as my first stage, then have a standard water-cooled West or Liebig after it, I'm thinking that I'd get low overall thermal stress and good
containment of hot acid vapor. Or is the water-cooled stage overkill?
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microcosmicus
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Glass (of any kind) will withstand heating up to its softening point without any ill effect ---
above that temperature, it begins to sag and gets softer as you heat beyond that point,
ultimately leaving you with a puddle of glass where your flask was. For both borosilicate
and soda-lime glass, that temperature is around 500C, so 337C is within the
capabilities of glass.
What wrecks glass is not heat, but thermal shock. As long as you take care to apply the
heat gradually and evenly and let the glassware cool back to room temperature gradually
and evenly, it won't crack if it isn't scratched and free form internal stress.
For what you are doing --- boiling a liquid --- the liquid acts as a heat bath and keeps
the temperature steady as long as you don't distill to dryness, which is a bad practice anyways.
The advantage of borosilicate glass is that it has a lower coefficient of expansion, so can cope
with larger thermal shocks before it goes kaput. With care, you can certainly distill your
H2SO4 in glass vessels just as it has been done since the time of Gerber.
MagicJigPipe, I'm glad there were legs still left within those wrecked pants
I suppose that urination would at least serve to wash and neutralize
some of the spilt acid 
[Edited on 7-3-2008 by microcosmicus]
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Pulverulescent
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Yeah, for one thing, I'd worry that my condenser would crack, even as an air condenser.
No way would I have water in it. . .H2S04 vapours should condense easily because of the high boiling point.
I don't want to endanger an RBF, either, or overheat teflon(teflon flu'?)!
And, using no lube might end with seized joints.
I'd certainly try it with a good retort, if I had one. Even then, though, the side-arm might get too hot to condense the distillate.
Oh, and before distilling I'd try to make sure the water was boiled off first.
MJP, when I was a kid I stuck carbon rods into a jar of battery acid, connected to the mains and switched on. . .a green arc formed even though there
was a half inch gap, and the acid fountained up and onto the floor. It was a polished wooden bedroom floor and I thought, "shit it's going to turn to
sawdust in a few months, and then I'll get a major bollicking. Nothing happened the floor but I had a few scares when the word floor came up in
conversation.
Let's just hope someone else does the distillation and tells us(tongue in cheek)here.
P
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Pulverulescent
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Right now, I've got several litres of dirty acid. It's in a demijohn with rubber stopper. 'Thought rubber was ok, but it's disintegrating with time
and now all this shit's sitting in the acid---in the middle of it.
I've just ordered a fritted funnel, though; should arrive any day.
If I want fresh acid, I'll electroplate copper from CuS04 sol..
An inert anode is soooooo useful---expensive but kinda essential, too.
P
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Armistice19
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I actually had a quick question, I just obtained a couple car batteries from a junk yard, They seemed to still contain at least very small amounts of
acid as the liquid fizzled when it came in contact with the concrete in my backyard. I filtered the acid through coffee strainers. As the lead sulfate
collected in the mesh of the paper, a clearer liquid dripped into the glass container, and I obtained an atleast somewhat purified weak acid. I then
bought a small propane camp-cooking stove from a sports outlet in order to boil the acid (this was much cheaper than buying a laboratory hotplate at
the time). I put a teflon skillet filled with cooking oil onto the flame, and a pyrex cooking glass full of the acid into this. After a while the acid
began to boil so I went over to a friends house while another friend checked on the acid for me. When I returned I found a yellow oily liquid at the
bottom of the pyrex glass just as I had wanted, but to my surprise it was not fuming. In fact, it was fuming less than it was when I was just boiling
off the excess water. I then proceeded to pour a drop or two onto concrete... no fizzle. Not being stupid enough to try it on my own flesh I skipped
that part and funneled it into a storage bottle, and tried again. I achieved the same result the second time, an oily, yellow, non-fuming, and
apparently unreactive liquid. This time when I funneled it into its bottle a drop of it splattered out and touched my leg....no burn, nothing, just a
warm oily liquid is all it apeared to be. What did I do wrong? Perhaps I boiled it too long and destroyed the acid?
“Imagination is more important than knowledge. For knowledge is limited to all we now know and understand, while imagination embraces the entire
world, and all there ever will be to know and understand.” -Albert Einstein
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12AX7
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Try diluting it with H2O. If it heats up and acts like an acid, good bet it is what it should be.
Tim
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ADP
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I'm interested in attempting a vacuum distillation of sulfuric acid from drain cleaner. If I do this I'll take some pictures. Does anyone know where
I can find a vapor pressure table for sulfuric acid?
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MagicJigPipe
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If it doesn't burn you instantly it is definitely not concentrated H2SO4. I got a pretty bad burn the other day from 35% sulfuric. Yes, it sat there
for about 30 seconds but that's only 35%! Concentrated will char your skin instantly. Go to a hobby store (Hobby Lobby) and get some pH paper if you
want to know for sure but I doubt you have any acid in there. How long did you boil it? It's possible that you boiled out all of the acid. Also,
NEVER use "Pyrex" glass that you buy from Wal-Mart for chemistry purposes. It will go up to 320*C easily to boil sulfuric acid but once it cools down
it WILL shatter. It IS NOT borosilicate.
"There must be no barriers to freedom of inquiry ... There is no place for dogma in science. The scientist is free, and must be free to ask any
question, to doubt any assertion, to seek for any evidence, to correct any errors. ... We know that the only way to avoid error is to detect it and
that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think,
free to think what they will, freedom can never be lost, and science can never regress." -J. Robert Oppenheimer
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Pulverulescent
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Armistice 19, the cooking-oil may have contaminated the acid when its temperature reached a certain point.
The boiling temperature of H2S04, 339*C, might be high enough to cause the oil to boil and spatter into the acid.
If the glass was pyrex, you shouldn't have needed an oil-bath.
Careful monitoring and a fume-hood would have helped.
Slow heating, without the oil-bath would have given the result you wanted.
The residue you were left with may just have been the oil that spattered into the glass---the acid having been mostly driven off.
P
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