Synthesis and distillation of conc. sulfuric acid

[Arthur]

S > SO2, Add H2O and you get H2SO3 not H2SO4. Go balance it yourself!

 

The three ways of making SO3 (for reaction to H2SO4) are Platinum catalyst, V2O5 catalyst and the Lead chamber process.

 

Research a lot more and the details will come to you. V2O5 is expensive Platinum is expensive, the lead chamber is big bulky method.

Edited August 14, 2009 by Arthur

[crazyboy25]

Is this for practical purposes or purely academic experimentation? If it is the former I suggest you stop and don't continue any further as you will be sorely disappointed. If you only want to make a few grams of dilute acid for the hell of it then I suggest you burn sulfur and pass the resulting SO2 through V2O5 catalyst or maybe a tube filled with catalytic converter beads. If you are lucky you might produce some SO3 which you can then bubble through water.

 

Or perhaps you can pyrolyze sodium bisulfate to yield SO3 then add that with water. Whatever you do good luck and be careful! This is dangerous stuff..

[inonickname]

I'd like to synthesize and distill concentrated sulfuric acid (mainly for the experience).

 

I'll be using sulfur dioxide gas in a closed container with a fine mist of water through a nozzle. The sulfur dioxide will slowly be added to a constant fine mist of water, where sulfuric acid will condense to the bottom of the chamber.

 

There are of course several safety issues etc. This will be carried out in a fume hood with ventilation etc. I'm concerned if there are any impurities which may form dangerous and reactive compounds when I burn off my sulfur. It is rubbermakers, and non acidic.

 

After synthesis, what is the best way to:

a) remove and dangerous impurities

concentrate the acid

 

Any other thoughts? I will burn the sulfur in a closed chamber, aerated with clean, dry air. I'll experiment to find the perfect way to do this and capture the gas.

 

Thanks guys

[inonickname]

Oh god- I just realized I stuffed up bigtime. I forgot that it was a certain set of circumstances that would yield H2SO4 from SO2- and I'm not making the acid in my mouth.

 

It was mainly for experience, so vanadium or platinum catylists probably aren't worth it to me. I'll just stick to good old commercial sulfuric.

[Mumbles]

H2SO3 does spontaneously convert to H2SO4. There is at least one mechanism involving the precipitation of elemental sulfur.

[Arthur]

For amateur production the "Lead Chamber Process" is possibly most suitable. See the big article on SMDB by Axehandle I think.

 

Basically take some sulphur and add about 20% KNO3 then burn in free air, the fumes (SO2 and NOx importantly) slowly react to SO3 and a different NOx, the SO3 can be dissolved in water and the NOx vented. This was the orriginal method anf sulphuric acid production and was done in huge room sized chambers, made of lead because nothing then was available in big acid resistant pieces. Probably the modern equivalent for DIY would be the 1000liter plastic tank that comes built onto a pallet. There is more than meets the eye to getting the system to work steadily at agood production rate and efficiency.

[inonickname]

Arthur; what are the more common NOx's produced and is there much of a risk of nitric acid being formed?

[Arthur]

You will need to refer to the original thread on SMDB and follow all the patent searching and theoretical chemistry that was done to bring the process into the realms of possibility for "home" chemists.

 

On a personal satisfaction level the Lead Chamber process can be replicated on a domestic scale in a 2+litre PET pop bottle. You may succede in making a few ml this way. IIRC the V2O5 process was the first to make oleum a viable product, but the catalyst could be poisoned. The Platinum catalysed reaction is more robust and is in current use. The platinum obviously being so valuable that it gets refined and reused as necessary