Sulphuric Acid Synthesis

[X-Wulf]

Hi all
I wonder if someone can help me, i'm trying to synthesise relatively concentrated (68% +) sulphuric acid, and just need some opinions on my method.
First, sulphur is burnt in air to produce sulphur dioxide. This is then bubbled through water to produce sulphurous acid. Oxygen is then bubbled through the sulphurous acid to produce sulphuric acid.
Will this work? What sort of concentration will i attain?

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Live Forever!

[Lagen]

If it worked the industry wouldn't be using expensive catalysts! In the past they used the lead chamber process which was far more complicated. I know it's simple to just criticise, so: Better start from pyrite (iron sulfide), or iron sulfate. The latter can be used to make oleum! I will post the procedure in Iron Sulfate...

Edit: No, I realised it is Iron(III) Sulfate and the Iron Sulfate topic mainly deals with Iron(II) Sulfate. So I will post it in the oleum thread, after I type it...

[This message has been edited by Lagen (edited August 21, 2001).]

[Nitro]

There are two old methodes for synthesis.
1 use an iron pan in an air tight glas beaker. you fill some water in the beaker and let the iron pan swimm on it.In the iron pan is an mixture of sulfur88% and 12% saltpeter.Then light it and close the beaker.Do it few times.With this methode you can make an 70% sulfuric acid.
And the other methode is older it works with cooper vitriol or alum.If you heat it and let the vapors in Water than you can make Oleum.I think an steel pipe will do it as an retort for this methode.

[-A-]

That must be the strangest procedure I have seen...

[Antonio]

Haha, Theres no way in hell you could get H2SO4 like that. Where do you come up with this stuff

[Disturbed]

Theres one way I know of making H2SO4 w/out high temp catalysts or anything too unreasonable. I haven't actually tried this, but it makes sense, and it came from a source I can trust, my old chem teacher, who is a total explosives nut =]
In one jar, pour some water and add some sulfite salts [used in winemaking to kill bacteria]. this produces SO2 gas, which you then bubble thru H2O2.. the two molecules combine [don't ask me how, like I said I didn't try it] and form H2SO4. I think that it sounds reasonable. So basically you end up w/ sulfuric acid with a concentration roughly equal to the concentration of H2O2 you started with.
If anyone does try this, post your results please! I haven't ever bothered to buy sulfite salts, but I have seen them for sale online before.

[Nitro]

Both methodes works.In the first methode the saltpeter(NOX gases) is the catalyst.And they have used it industrial 1750 or so.It was befor the lead chambers came.
And the other with the vitriol was first used
500 Bc.And they have made directly nitric acid with an mixture of vitriol alum and saltpeter.

[X-Wulf]

-A- and Antonio, I just tried it and DID get sulphuric acid! it was extremely weak, but was still the desired product.

Nitro, thanks for the info, i'll try it a.s.a.p.

Disturbed, what sort of concentration of hydrogen peroxide is needed to get a decent concentration of H2SO4? Is the 3% stuff sold at pharmacies ok?

Lagen, any help in the production of oleum would be greatly appreciated

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Live Forever!

[This message has been edited by X-Wulf (edited August 22, 2001).]

[X-Wulf]

Nitro, if the KNO3 is a catalyst, then i'll assume that the SO2 is being converted to SO3 right? So then the longer/more often you burn the composition in the beaker, the more concentrated the H2SO4 will become, right? So then eventually, you'll start to produce oleum (H2S2O7)?

[This message has been edited by X-Wulf (edited August 22, 2001).]

[Nitro]

Yes but what i read it works only for an 70% sulfuric acid.And yes if you often burn the mix. so you reach the 70%.
For oleum they have used the second methode.

[X-Wulf]

Nitro, isn't copper vitriol merely hydrated copper sulphate i.e. CuSO4.5H2O?
if so, must this be burnt and then bubbled through already existing H2SO4 or just water to make oleum?

another thought, if copper sulphate works, why not other sulphates?
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[This message has been edited by X-Wulf (edited August 22, 2001).]

[Disturbed]

X-Wulf,
I was under the impression that you could use any concentration of H2O2. However, if I was going to do this, I'd use 30%, because it would take way too much 3% H2O2 to actually make a useful amount of conc. sulfuric acid.

[Mr Cool]

I agree, sulphuric acid is a great low explosive.
Was this the best section? I doubt it...

[Nitro]

Over 200 C it dehydrates and if you heat it to strong it turns black and gives SO3.For oleum you need to dehydrate it, and yes cooper sulfate works too.(I over saw it ,in the book where i have the idea from are no chemical formulas)
P.S Where do you buy your vitrol or cooper sulfate?

[Anthony]

Moving to Misc...

[X-Wulf]

Nitro, I get copper sulphate from the local hobby/science shop where they sell it as a refiller to little crystal kits. You can also get it from some plant nurseries (don't know what it's used for though).
Is there an accurate way to test the concentration of sulphuric acid? (or even just to make sure it is sulphuric and not just sulphurous?)

[Disturbed]

To test the concentration, I'd just find a density table and weigh the stuff. The other way to do it is to buy/build a hydrometer. There was the thread on how to do that, and that will give you the density w/out weighing. You'd still have to find that density table tho! Otherwise, one way they do it to test the concentration of battery acid, to see if it needs replacing, is to put a drop on a sheet of metal and use a tool [don't remember what it's called, sorry] to measure the angle of refraction. That will give you the concentration right there, though I doubt any person on this forum has one of those gizmos.

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kein mitleid fur die mehrheit

[Lagen]

<font face="Verdana, Arial" size="2">You'd still have to find that density table tho!</font>What? I have personally posted the density tables for HNO3, HCl and H2SO4 here! To test for sulfuric acid, just try to precipitate the sulfate anion with calcium or barium.

[X-Wulf]

Disturbed: thanks for the info, i'll try and dig up some stuff on refraction of liquids (though this is probably directly associated with its density)
Lagen: i found your density table (here http://theforum.virtualave.net/ubb/Forum5/HTML/000887.html )
but it's for H2SO4, HCl and NH3, was the NH3 supposed to be HNO3?

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Live Forever!

[This message has been edited by X-Wulf (edited August 28, 2001).]

[Disturbed]

Whoops! Sorry bout that Lagen!
Thx for the useful info tho.. I've been thinking about waaay too much, waaay too late these past few nites http://theforum.virtualave.net/ubb/smilies/smile.gif

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kein mitleid fur die mehrheit

[Lagen]

K
The HNO3 table is in the "Nitric Acid manufacture" thread.

[X-Wulf]

These methods seem rather long, laborous, and somewhat inefficient http://theforum.virtualave.net/ubb/smilies/frown.gif all i get is really, really weak stuff

but ... another method i thought of:
Electrolyse NaCl solution to form Cl and H, bubble these gases through water and you should get ClOH. In bright light, or if heated slightly, this forms concentrated HCl. Now simply ion-exchange with CuSO4 (for H2SO4) or KNO3 (for HNO3).
i tried this briefly, but not enough Cl dissolved in the water, and hence my acid was pretty weak.

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Live Forever!

[SofaKing]

Considering that you would be dealing with noxious gases (SO2-SO3) that you have thought about proper saftey precautions.

This shouldn't be considered a indoor project unless you have a fume hood. So for most of you that means outdoors only. A gas mask wouldn't hurt either. And gloves for dealing with the acid.

http://cator.hsc.edu/~kmd/caveman/projects/acid/index.html This page off http://cator.hsc.edu/~kmd/caveman/ this site has a tried and tested method for producing lab quantities of sulfuric acid. It's also a really good site.

Or If you live in the US go to the hardware store and just buy a half gallon of the stuff. That's what we have industry for.

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With Knowledge we find Truth - With Truth we find Freedom

[nbk2000]

CuSO₄ + heat -> CuO + SO₃

SO₃ + H₂O -> H₂SO₄

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"The knowledge that they fear is a weapon to be used against them"

Go here (http://members.nbci.com/angelo_444/dload.html) to download the NBK2000 website PDF.

Go here (http://briefcase.yahoo.com/nbk2k) to download the NBK2000 videos.

[atropine]

most efficient catylyst is vanadium pentoxide. This is the same thing they make spaaners and shit from. Thing is its so damn strong that you cant really powder it.

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all wize men have unwize fantasies &lt; ^ &gt;

[X-Wulf]

I'm geaussing that you meant "spanners", the ones you would use with nuts & bolts?
Could be a problem to use pratically if it can't be powdered. Is it possible to electro-plate steel gauss or something with it?

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Live Forever!

[rikkitikkitavi]

Vanadnium is used as a alloy in special-steel, content about a few % w/w. But you dont need much to make a catalyst, mix it with some K2SO4 (about 5 %) to increase efficency.

You can also try platinum (expensive) and ironoxide (less efficient about 50 %, but cheap)

The main problem with absorbing SO3 into water is that it will create a H2SO4 mist when it reacts with the water. Industrially it is always absorbed in 98% H2SO4 and then dilluted. This mist is a drag to absorb...or condense since the H2SO4 particles are extremely small.

Lead chamber process:
A mixture of NO2 and SO2 reacts with water to form NO and H2SO4 (lead-chamber process,used before the contact process was invented). It used buildings lined with lead-sheets used as reaction chambers.

H2O +SO2 +NO2 => H2SO4 + NO
NO + 1/2 O2 => NO2

By bubbling SO2, NO2 and air through several cascaded absorbers you will get H2SO4 in each one.

Main problem is that above 65 % H2SO4 the above reaction is not effective , so this sets the upper limit of concentration. In the old days they solved this by distilling the acid up to 98 %, is more simply boiled it in open pans until it was the right concentration, some acid (5-10 %) was lost this way.


/rickard

[This message has been edited by rikkitikkitavi (edited September 30, 2001).]

[X-Wulf]

Thanks for the info, though i was aware of the lead chamber process. This, however, requires NO2.
Any ideas as to how to obtain/produce this?

Theoretically, chemical supply houses may sell certain chemicals (such as acids, ntrates and chlorates/perchlorates) to the public, assuming that a legitimate (and reasonable) "excuse" is provided. The problem here is thinking up such an excuse (especially for the ClO4's).

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Live Forever!

[CodeMason]

KNO₃ is such a legitamite chemical that I've ordered it numerous times through pharmacists, no questions asked. They probably all know it can be used in explosives manufacture (everyone knows what's in black powder), but they like to trust people. I buy it from a fertilizer store nowadays.

[CodeMason]

So H₂O₂ + SO₂ -> H₂O + SO₃ -> H₂SO₄?

The hydrogen peroxide would probably need some sort of catalyst, manganese dioxide is too fast acting, maybe the sulfur dioxide would be a catalyst in and of itself?? This seems like a good method, as the starting materials, sulfur and concentrated peroxide are easy to get, plus I could easily construct the apparatus, using wire, a funnel, a porcelein dish and an alcohol lamp for a sulfur combustion chamber, and from the top of the funnel would be an acid proof tube leading into the beaker of conc. H₂O₂. Does this sound like it would work? If my scanner weren't broken I'd draw up a diagram to illustrate it better.

[a_bab]

Ahaaaa....So that's why I wasn't able to obtain H₂SO₄ from CuSO₄*5 H₂O and my coke (carbonic acid) http://theforum.virtualave.net/ubb/smilies/wink.gif



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Damn, I got a nitro-headache again...

http://move.to/pyromania

[rikkitikkitavi]

I read up and found out that sodium bisulfate (NaHSO4) decomposes into sulfuric acid and Na2SO4 in alcohol (C2H5OH)

The problem is that the sulfuric acid might react with alcohol (dehydration) and forming ether or ethane if I dont remember wrong, especially at higher temperatures.

I like to mention that I haven' t tried it out, but before I waste time and money :

Anybody having any idea about how to separate the products. Distillation seems like a good way to produce ether...and diluted sulfuric acid.

Na2SO4 is insoluble in alcohol and not very soluble in H2SO4, so much I know.

/rickard

[rikkitikkitavi]

Ahh it is good to be back...

I have done some experimenting with NaHSO4.
When dissolved in alcohol, Na2SO4 preciptates since this is almost insoluble in pure alcohol and only about 0.2 % in 50/50 alcohol/water.

Left is a mixture of sulfuric acid and alcohol.
So far I havent figured out a way to
separate these two, but I guess distilling off the alcohol would work (forming ether and water, the later diluting the acid)

Did find some very interesting patents about making sulfuric acid from waste gas to:
Us Patent # 3,947,560

/rickard

[Jumala]

I found a very interesting site about making Oleum in the midage.
It is the Nordhäuser method. They made oleum since 1650 by heating the different kinds of vitiol, found in the harz mountains near nordhausen, in earthenware retorts. The white smoke (spirit of vitriol) was condensed and collected.
It was a high concentrated H2SO4 with additional SO3 in solution. This method was used for 200 years.

This method can be used to concentrate H2SO4 to oleum like said in this topic before.

The text is in german language but perhaps you can use a translator.

The original source is the book from rudolph glauber "Teutschlands Wolfart" from 1656.
Does anyone knows where to get a copy of those very old books?

http://dc2.uni-bielefeld.de/dc2/wwwcu/vitriol.htm

[rikkitikkitavi]

I know that the preciptate is Na2SO4 since I have filtered it out , washed it with alcohol and dissolved in water, pH is about 5. It is probably impossible to get rid of ALL acid with this.

NaHSO4 dont dissolve in alcohol, it decomposes! Netiher does Na2SO¤ when the water concetration is low.

/rickard

[rikkitikkitavi]

First, it is impossible to wash out all NaHSO4 from the Na2SO4. But with a pH at about 5 the concentration of NaHSO4 is less than 1 % ... so with 99 % yield I call it good enough.
But that is not the problem, it is to separate the acid from the alcohol.

I make my NaHSO4 from Na2SO4 and H2SO4 !
I am just trying out different ways to make sulfruic acid , but I already have a few gallons at home... It is just for fun.
Cant buy it in Sweden, where I live, not even 37 % battery acid without permissions from the county board..

But you can make like this:
(NH4)SO4 is a common fertilizer.
(NH4)2SO4 => NH3 + NH4HSO4 (at about 100 C-250 C)

Na2SO4 + NH4HSO4 => NH3 + 2 NaHSO4 (at about 250-300 C)

NaHSO4 is commonly used as a agent to lower the pH in pools. That is also a source of it.

/rickard

[rikkitikkitavi]

Heating:

(NH4)2SO4 => NH4HSO4 + NH3

NH4HSO4 => N2 ,NH3,SO2 , H2O mostly.

according to litteraure. but when I tried to heat NH4HSO4 it didnt smell of SO2 at first but gave a very irritating non-smelling odour similar to what you get when boiling diluted sulfuric acid, so some SO3 must be formed. After a while a strong smell of SO2 emerged. But its very slow.
If you could converte NH4HSO4 into NaHSO4 this can be decomposed to Na2SO4 and SO3
(se previous post)

Trivalent metall sulfates gives M2O3+ SO3 when heated , divalent metall sulfates decomposes at such high temperatuers that SO3 decomposes into SO2.

/rickard

[rikkitikkitavi]

yepp,that irritating smell was probably SO3
reacting with moisture in my nose forming
sulfuric acid, but I can only say:

I didnt inhale...

I have had worse coffs after a good joint or a cigarette, it all a matter of the dose.

/rickard

[Cricket]

I was watching TLC a while ago and it was discussing the first sewage systems in London (I think it was there) and it said that there were bacteria that lived in the shit water at the bottom of a sewer and make some kind of gas that bacteria living on the top of the sewer needed and then one of its waste products was H2SO4. I thought maybe we could use this to make H2SO4 (dialute probably) and then concentrate it maybe? I haven't heard this mentioned before so I though I would give it a shot. Has anyone heard of this before?

[kingspaz]

sounds like a good idea...could be like making alcohol except making H2SO4 :D ...although would the bacteria be able to survive in conditions greater than 5% concentration?

[Cricket]

Yea, thats why I am not sure if I remember it correctly. I didn't know if they could survive. I would like alcohol more myself, but everyone could use a little H2SO4 here and there :) .

[croc]

When I tried converting dry acid to H2SO4 on a cold day (may have been the problem) sodium sulphate didn’t crystallise out but the NaHSO4 just sat without changing. Small bubbles began to form which I think were ethylene CH2CH2 produced by the dehydration of alcohol. Maybe heating it would speed up the reaction (I didn’t have a hotplate handy at the time) this can then be heated for the sulphuric acid to dehydrate the ethanol and release ethylene gas. The H2SO4 can then be distilled out and then boiled to evaporate its water.


I make my NaHSO4 from Na2SO4 and H2SO4 !
/rickard

How is NaHSO4 made? if both are heated togather would they refprm NaHSO4?

[meselfs]

The NO2 catalysis is IMO the best way.

Somewhere in the Nitric Acid forum, I remember reading that someone heated nitric acid with sulfur in it. It began reacting, releasing NOx, which was collected in a container with water. Left behind was sulfuric acid. The NOx solution is, ofcourse, Nitric acid, so it can be concentrated. Thus you don't lose any nitric acid, except for a tiny bit in lost vapors & stuff...

Just imagine, you could literally make gallons of quality sulfuric acid this way.

[TheBear]

The SO2 + H2O2 has been tested and it works. Just wanted to let you know. (SO2 was produced by simply burning sulfur and bubbling the SO2 produced through ~20% H2O2). Resulting sulfuric acid is about 55% (final concentration depends on H2O2 conc.) which of course can be boiled down to desired concentration.

[penguin6636]

I tried the H2O2 method one time. I used 3% and ran the SO2 from burning sulfur through 3 flasks each filled with 100mL H2O2. Even then I could still smell a bit of SO2 at the end. I boiled the 300mL down to about 30mL when I was done. The pH test indicated it was very acidic so I put in some NaCl heated it up and bubbled the HCl through about 20mL of water until the gas production ceased. The HCl acid was strong enough to dissolve a handful of Al foil.

To burn my sulfur I put it in a stoppered 500mL flask and pumped air through it. I had some difficulty getting the sulfur to ignite but once it lit it burned well so long as the O2 was flowing through it. I got lots of sulfur vapor while trying to get it to burn, but if you lift the stopper off and hold a flame above the mouth of the flask it will get it all burning. I know this method wasn't the best but I came up with bubcus for other ideas. What has anyone else done to burn their sulfur?

[megalomania]

...pumped air through it. I had some difficulty getting the sulfur to ignite but once it lit it burned well so long as the O2 was flowing...

Just to clarify, were you running air or pure oxygen through your sulfur burning flask?

[Nitro]

Before the lead chamber process came they made Sulfuric acid in big Glas flasks with an little bit water on the ground.They set in an iron pan.On that pan they burnd Sulfur with an content of 12% up to 15% KNO3 or NaNO3.The Saltpeter produced NO2 and the NO2 oxdized the SO2 to SO3.The formed NO reacts with the remaining air in the chamber back to NO2.Later they used an oven so they could burn the sulfur continuous.That method works for concentrations up to 70%.Because in lag of Water it forms in the H2SO4 crystalls of SO2(OH)O-NO.If you can make it with an burning oven so you have an small industrial styl sulfuric acid plant at home.

[penguin6636]

Just to clarify, were you running air or pure oxygen through your sulfur burning flask?

Sorry for the confusion. I was testing for proof of concept so I was just using air. The problem with getting the sulfur to ignite seemed to be that it needed a better source of ignition. I was using a hotplate instead of burner as it did less damage to my rubber stoppers. When using a burner it was quite difficult to get the sulfur burning instead of just boiling, even with plenty of air flowing through the flask. Introducing a naked flame near the mouth of the flask and then stoppering it again after the vapors lit and got the rest burning seemed to work. This would be entirely too tedious to actually make H2SO4 though.

[tranquillity]

A possible way to ignite the sulphur might be to add a very small amount of chlorate/sulphur mix as a pile in the centre of a large amount of sulphur in the reaction vessel. The chlorate could then be ignited with a strong acid or heating which should hopefully continue to burn the rest of the sulphur with a continual stream of air/oxygen.

[Alexires]

Penguin6636 - I had the same problem, but my flame kept going out. I figured that I needed a better air pump (I was just using a cheap one from a pet store). Otherwise, 2 or 3 could be used in tandem to provide enough O2.

If you are having a few problems with getting it to ignite, you could experiment with adding differing amounts of KNO3 to your sulphur before you add it to your burner. If you used only a small amount, it would assist in raising the temperature of the sulphur to auto-ignition, as well as possibly keeping it burning.

To keep a flame going, one might use the ignition of an old oven. You know, where it ticks 2-3 times a second to light the gas on the elements. It would work just like a butane lighter I'd hope.

If there is no flame, you will get finely powdered sulphur in whatever you are using to collect your product. While this might not be a bad thing for some applications, it is annoying when you come back to find all your tubing blocked up with condensed sulphur...

[DetaDude]

Try using ozone for the oxidizer on the SO3..........works slick.

[Jome skanish]

If you are producing ozone, you might just as well just bubble it through water with powdered sulfur in it.

S + H2O + O3 ---> H2SO4.

Hell, if you used a electrochemical cell with a sulfuric acid electrolyte you might as well skip a bubbler and let the ozone produced react with sulfur and water directly at the anode, effectively getting a "sulfuric acid from sulfur in one pot" machine.

[DetaDude]

J.S.
Care to elaborate on your theory? Introduce ozone into a stream of SO2 and get instant SO3 bubble through H2SO4 and dilute as needed. Works for me. But you must have a good ozone source. If your O3 is weak (to diluted) results are poor.

Try it you'll like it.

[Jome skanish]

What source of ozone are you using? At what rate does it produce ozone? How much H2SO4 have you produced using this method? How did you produce SO2?

AND WTF is "ur", "thru"? Sounds like language abuse to me, 14-year old h4x0R slang. It gives me a headache.

[fluoroantimonic]

I'll believe that ozone works when I see it... And any way you go about it, ozone is going to be a major headache to produce in the large quantities needed.

The best way to get sulfuric acid *especially if you need over azeotrope acid or oleum* is to take some scrap iron, hit it with drain cleaner of battery acid to make FeSO4 (you might be able to buy it at a garden store), then put it in a steel tube and heat it up to 600*C with a dry air current the whole time. The exiting air/SO3 mix is bubbled into sulfuric acid to concentrate it too 100% or higher (ie. oleum).

Oleum is extremely expensive to get from a chemical supplier and impossible to buy any other way. It also happens to be very useful in syntheses that require a mixed acid nitration and many others, like various war gases, etc.

[fluoroantimonic]

The other way to OTC SO3 is through metaphosphoric acid. HPO3 produced from OTC phosphoric acid or ammonium phosphate fertilizer if powerful enough to dehydrate sulfuric acid to SO3. IIRC B2O3 produced from borax is also usable.

The process is simple, dehydrate phosphoric acid in a copper crucible up to 400*C or so with a propane torch, then mix with the appropriate amount of azeotropic sulfuric acid and heat. Run the vapors into more concentrated H2SO4 to produce oleum. The phosphoric acid can then be re dehydrated and used again.

From what I hear oleum is extremely useful for many nitrations, increasing yields substantially or in some cases is essential. It is also a useful reagent for many organic syntheses.

AFAIK HPO3 can also dehydrate HNO3 to N2O5 which also some vary handy applications pertaining to explosives. Like directly nitrating exotic things, etc.

[akinrog]

The other way to OTC SO3 is through metaphosphoric acid.
AFAIK HPO3 can also dehydrate HNO3 to N2O5 which also some vary handy applications pertaining to explosives.

Not to contest what you said, but I would be very glad if someone (or you) may provide references (and files) for these procedures. Regards.

[fluoroantimonic]

sciencemadness dot org/talk/viewthread.php?tid=727&page=1#pid6198

Read the whole thread. The stuff pertaining to the use of metaphosphoric acid is in the last two or three pages.