Sciencemadness Discussion Board - Concentrating dilute sulphuric acid(battery acid) without distillation

Concentrating dilute sulphuric acid(battery acid) without distillation

Bhaskar - 4-3-2012 at 22:25

Hi guys,
I was going through some sites for concentrating battery acid and i found out that it could be done by boiling it (40%-45%) in a beaker to reach maximum concentration which will be marked by the production of whitish fumes with a few safety precautions to go with it. My question to you all is, what is the highest concentration that it could reach?, because i read on one site that it could reach a maximum of 95% and(if any of you see nurdrage vids) it can reach to about 98%, and umm... I dont have a weight meter or something to compare with the density of concentrated sulphuric acid, so please don't ask me to,
Regards,
Bhaskar

marko - 5-3-2012 at 00:58

98% is the azeotrope with water, so you can't do better than that by evaporation.

I presume once you get within a couple percent of there, you start evaporating a fair bit of the acid as well, that's probably why it is mentioned 95%.

http://www.qvf.com/en/processsystems_3/mineral%20acids/Conce...

You should be able to titrate it to figure out the strength...

cyanureeves - 5-3-2012 at 04:52

i tried it and it started to fume really,really bad way before it got anywhere near drain cleaner strength.it turned brown also and you have to turn the temp higher and higher because it changes boiling point.i still have more than half of the new battery acid i bought in a bag from oreilly's auto store.but it was really cheap!

Pulverulescent - 5-3-2012 at 05:37

If your battery acid turned brown, it contained silicon carbide!
Hot 98% sulphuric acid decomposes SiC to SiO2 and CO2.

Bot0nist - 5-3-2012 at 06:16

Boil it down and then try and add H2O2 while strongly cooling. This will generate exotherm and fizzing. The fizzing is any organic or other easily oxidizable waste in the acid being released. Then reconcentrate. The color may return when it is boiled down again though.

Search forum for; clean sulfuric acid, h2so4, drain opener, dirty sulfuric acid, etc. There are TONS of threads about this. Happy reading.

Bhaskar - 5-3-2012 at 23:38

thank you marko!

jamit - 6-3-2012 at 00:00

I know you didn't ask for this but boiling down battery acid to concentrate it is too dangerous and you can attract attention in a negative way... unless you live in an rural area away from noisy neighbors. You're right, the fumes start around 70% concentration and you to need boil it for another several hours if you want 95%. Nurdrage doesn't mention the danger involved in boiling down the acid but that's because he's experienced and he has the equipment to do it.

My advice about sulfuric acid is this. Use drain opener, rooto... to say distill other acids like acetic or nitric acid.
use the battery acid, which is about 35%, as is, for making other reagents.

And if you need really pure sulfuric, you can always buy it on ebay for about 30.00 for 1liter -- ACS grade!

[Edited on 6-3-2012 by jamit]

[Edited on 6-3-2012 by jamit]

[Edited on 6-3-2012 by jamit]

[Edited on 6-3-2012 by jamit]

Bhaskar - 6-3-2012 at 00:19

thanx for the advice Jamit, by the way, drain opener is not sold in my country, I don't have time to ship chemicals, they are too expensive at the moment(for me) and i have a question-would it take HOURS to boil down the acid? i mean HOURS?

Bot0nist - 6-3-2012 at 05:41

Depends on the volumes, of course. Are you working with half a liter, or 10l, etc.

Bhaskar - 6-3-2012 at 07:11

Quote: Originally posted by Bot0nist

Depends on the volumes, of course. Are you working with half a liter, or 10l, etc.

I was going to buy some after some research, could you please help me in calculating the time taken and amt. of aezotropic concentration of sulphuric acid left after boiling down half a litre of it?

blogfast25 - 6-3-2012 at 08:40

Quote: Originally posted by cyanureeves

i tried it and it started to fume really,really bad way before it got anywhere near drain cleaner strength.it turned brown also and you have to turn the temp higher and higher because it changes boiling point.i still have more than half of the new battery acid i bought in a bag from oreilly's auto store.but it was really cheap!

I tried boiling down 50 % years ago and it too fumed like mad (no distillation kit used).

On AmazingRust.com there a good descrition of the process.

Bhaskar - 6-3-2012 at 23:27

Quote: Originally posted by blogfast25

Quote: Originally posted by cyanureeves

That was the site I was talking about.

On AmazingRust.com there a good descrition of the process.

cyanureeves - 7-3-2012 at 16:49

i read that you have to boil off 2/3 of the battery acid and it took hours and hours for me,like 5hrs. before i finally quit.i still have it as an unfinished project of mine but i need to be out in the boonies.i made a box and cut it in half,set it on its side,put the electric camping stove hot plate in the box,placed those gas stove burner guard things on the heating coil to keep the glass coffee pot from making contant,then placed a fan in front of the box and covered the whole thing except the fan with a towel. i knew that with that many fumes it would eat up my stove top so i used the fan to dump the fumes.i thought the acid and heat would burst the coffee pot but it didnt.

Bhaskar - 8-3-2012 at 00:24

Quote: Originally posted by cyanureeves

i read that you have to boil off 2/3 of the battery acid and it took hours and hours for me,like 5hrs. before i finally quit.i still have it as an unfinished project of mine but i need to be out in the boonies.i made a box and cut it in half,set it on its side,put the electric camping stove hot plate in the box,placed those gas stove burner guard things on the heating coil to keep the glass coffee pot from making contant,then placed a fan in front of the box and covered the whole thing except the fan with a towel. i knew that with that many fumes it would eat up my stove top so i used the fan to dump the fumes.i thought the acid and heat would burst the coffee pot but it didnt.

Cool.Hope you were successful!

Endimion17 - 8-3-2012 at 04:25

Quote: Originally posted by Bot0nist

Boil it down and then try and add H2O2 while strongly cooling. This will generate exotherm and fizzing. The fizzing is any organic or other easily oxidizable waste in the acid being released. Then reconcentrate. The color may return when it is boiled down again though.

Search forum for; clean sulfuric acid, h2so4, drain opener, dirty sulfuric acid, etc. There are TONS of threads about this. Happy reading.

I wouldn't add hydrogen peroxide to a concentrated sulphuric acid. Hydrogen peroxide is similar to water and that could lead to the same consequences as adding water to conc. sulphuric acid.

Bot0nist - 8-3-2012 at 05:46

Obviously, one would add the peroxide to the acid, of course. I would hope this would be apparent to anyone who has ever diluted sulfuric acid, or even read any basic practical chemistry text. I can't edit the misleading post now, but anyone who adds it in the wrong order will be immediately aware of their mistake. Add acid to water (or peroxide in water).

weiming1998 - 8-3-2012 at 06:11

Wouldn't the black stuff inside the battery be primarily PbO2/PbSO4/metallic Pb?
Apart from substances like traces of SiC, oxidizable organic compounds in car battery acid is minimal. Would decanting get rid of the PbO2/PbSO4 easily, or would it mix with water to form a suspension like MnO2, which at the density of 5g/cm3, is very heavy, but it still forms a suspension. If the Pb compounds form a suspension, how would it be removed from the acid without distillation or glass wool filtering?

But if it is dirty drain cleaner, for instance, the H2O2 would be of much greater use.

Bhaskar - 11-3-2012 at 09:58

Can 70% boiled sulphuric acid be profitable for catalysis of acetone peroxide?
Is it high enough?

Bot0nist - 11-3-2012 at 11:54

Profitable? No, defiantly not. I can think of no instances of TCAP having any monetary value at all. Even a depressed jihadist would think twice about it. Would the H2SO4 work? Yes.

TCAP is much less finicky in its synthesis than is HDMT or even MEKP. In fact, the slightly diluted acid would likely be better than concentrated H2SO4 because it would produce much less exotherm upon addition than the 98% concentration would, which would help reduce the time between drop-wise additions of the acid, and how aggressive your cooling needs to be. Still, it is important that the temperature stays very near 0°C during the additions, and throughout the procedure to ensure that you have the more useful* and chemically stable trimer.

* I say useful very lightly. I mean that it is better at doing work that the dimer, but still to sensitive to be useful at all, IMO.

[Edited on 11-3-2012 by Bot0nist]

cyanureeves - 11-3-2012 at 14:31

i just brought out the battery acid i boiled down last year that i had stored away in a vinegar bottle and poured some on an unknown metal then added water and it became super hot. since then i've bought rooto and dudadiesel acid thinking my acid was not good.sometimes its two steps back.

entropy51 - 11-3-2012 at 16:16

Quote: Originally posted by cyanureeves

since then i've bought rooto and dudadiesel acid thinking my acid was not good.sometimes its two steps back.

Why don't you titrate some of it and find out how good it is?

Why settle for seat of the pants "tests" when you could do it quantitatively?

If you don't know how to make standard acids and bases and do a decent titration, you should really learn. At least if you are serious about chemistry.

Bhaskar - 11-3-2012 at 21:19

Quote: Originally posted by Bot0nist

Profitable? No, defiantly not. I can think of no instances of TCAP having any monetary value at all. Even a depressed jihadist would think twice about it. Would the H2SO4 work? Yes.

TCAP is much less finicky in its synthesis than is HDMT or even MEKP. In fact, the slightly diluted acid would likely be better than concentrated H2SO4 because it would produce much less exotherm upon addition than the 98% concentration would, which would help reduce the time between drop-wise additions of the acid, and how aggressive your cooling needs to be. Still, it is important that the temperature stays very near 0°C during the additions, and throughout the procedure to ensure that you have the more useful* and chemically stable trimer.

* I say useful very lightly. I mean that it is better at doing work that the dimer, but still to sensitive to be useful at all, IMO.

[Edited on 11-3-2012 by Bot0nist]

By profitable, I meant yield of TCAP, and as it's a good, however extremely dangerous explosive, It can have it's uses if other explosive's synthesis cannot be performed.