Sulfur Dioxide

[Theophrastus]

Recently, I've been thinking a lot about preparation, and methods of synthesis for various compounds, and amongst these, I've thought of producing sulfur dioxide, in some way, and then bubbling it, through a dilute hydrogen peroxide solution. As a result, this ought to yield a dilute solution of sulfuric acid, (about 5%, based upon the type of hydrogen peroxide I have) which I can then boil down, to a more feasible concentration of approximately 15%. (roughly) My only question, is in the generation of the sulfur dioxide. The obvious way, would be simply to burn sulfur crystals, however, I am unsure where these can be obtained. I do have various sulfides, (FeS2), which I suppose, upon heating, will oxidise to SO2 and Iron Oxide, but what are the temperatures required, for a such a reaction, to take place? If the temperatures are too great, are there any alternative ways to produce the SO2, necessary for the reaction to occur?

 

Ps: To prevent any furor, or unnecessary worry, I am well aware of the toxicity of this compound, and shall plan accordingly.

[UC]

Recently, I've been thinking a lot about preparation, and methods of synthesis for various compounds, and amongst these, I've thought of producing sulfur dioxide, in some way, and then bubbling it, through a dilute hydrogen peroxide solution. As a result, this ought to yield a dilute solution of sulfuric acid, (about 5%, based upon the type of hydrogen peroxide I have) which I can then boil down, to a more feasible concentration of approximately 15%. (roughly) My only question, is in the generation of the sulfur dioxide. The obvious way, would be simply to burn sulfur crystals, however, I am unsure where these can be obtained. I do have various sulfides, (FeS2), which I suppose, upon heating, will oxidise to SO2 and Iron Oxide, but what are the temperatures required, for a such a reaction, to take place? If the temperatures are too great, are there any alternative ways to produce the SO2, necessary for the reaction to occur?

 

Ps: To prevent any furor, or unnecessary worry, I am well aware of the toxicity of this compound, and shall plan accordingly.

 

Roasting metal sulfides takes an enormous amount of heat and is appropriately done in a furnace. H2O2 is generally stabilized with assorted phosphate buffers or phosphoric acid, which means that these will be contaminants in yoru final product. By far, the easiest way to make lots of SO2 is to acidify and gently heat bisulfite or metabisulfite (available fairly cheaply from wine making supply places) solutions. Ideally you'd use a non-volatile acid, perhaps cheap drain cleaner H2SO4 that is too dirty for direct use. The gas will have water vapor in it, but I doubt that is an issue if you're trying to just make aqueous acid in the end.

 

If the seals on your apparatus aren't good enough, you will definetly smell it. The SO2 causes a choking, burning sensation and always makes me sneeze a lot.

[max.yevs]

well iron sulfide, i haven't had the pleasure of encountering it, but i thought it ignited at room temperature...?

 

isn't it pyrophoric?

[Theophrastus]

Oh my god! Pyrophoric? At first, at your comment, I admit I was greatly dismayed, as looking it up, I did find, to my surprise that it was pyrophoric, however, my specimen, does not spontaneously burst into flame, which is a good thing, probably a testament to its relative purity, perhaps, however I seem to doubt this fact. The process described on a site, of the compound's burning to produce either sulpher dioxide, or, if no oxygen is available, its decomposition to iron, and sulphur, I found to be cohesive with the process I envisioned, in regards to the reaction itself, but far more dangerous, than I thought, as it seems that while the reaction would occur, it would seem to accelerate violently. Certainly not something for the faint of heart, and those who are not yet experienced enough, to properly contain such a reaction. Truthfully, I fall into the second category. That taken into account, I've disbanded my original idea, and instead, I suppose I can use UC's idea, of heating metabisulfites to produce a metal oxide, and sulphur dioxide, creating a simple ester, within the apparatus to check for any leaks, prior to performing the actual experiment.

Edited March 20, 2009 by Theophrastus
mistakes found.

[max.yevs]

ah, that's interesting...

 

i do apologize, my experience with chemicals does not exceed what you could buy at the local supermarket, so most of the things i know are looked up...

 

but i do like the idea of bubbling SO2 into H2O2 instead of SO3 into H2O...

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Consecutive posts merged

I was down at a hardware store today, and i happened to find a big case of sodium metabisulfite, used for treating rust stains (i guess Fe2O3 + Na2S2O5 > Fe + Na2S2O8 or something similar?)...

 

i read somewhere that sodium bisulfite releases S2O when mixed with water, but i hope you have the equipment to catch it!

[nitric]

its over exaggerated, it pyrophoric when you have it in gas form, try to do that, or in like specialty, super ultra fine powder in a pure oxygen atmosphere. For what the home chemist has this is no problem at all.

[max.yevs]

you can try heating iron sulfate (steel or iron + sulfuric acid or a persulfate)

2FeSO4 > Fe2O3 + SO2 + SO3

which with aqueous hydrogen peroxide may yield sulfuric acid

SO2 + SO3 + H2O2 + H2O > 2H2SO4

 

if this works, the sulfuric acid will be twice the concentration of your hydrogen peroxide.

 

you can then react that sulfuric acid with iron or steel to make iron sulfate and repeat the process all over again!

[UC]

ah, that's interesting...

 

i do apologize, my experience with chemicals does not exceed what you could buy at the local supermarket, so most of the things i know are looked up...

 

but i do like the idea of bubbling SO2 into H2O2 instead of SO3 into H2O...

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Merged post follows:

Consecutive posts merged

I was down at a hardware store today, and i happened to find a big case of sodium metabisulfite, used for treating rust stains (i guess Fe2O3 + Na2S2O5 > Fe + Na2S2O8 or something similar?)...

 

i read somewhere that sodium bisulfite releases S2O when mixed with water, but i hope you have the equipment to catch it!

 

no, just metabisulfite is a good reducing agent and is acidic. [ce] Fe2O3 [/ce] is fairly easily reduced to Iron (II) ions under these conditions and dissolves. Metabisulfite is just a dehydrated form of bisulfite and yes, [ce] SO2 [/ce] will escape an aqueous solution of it.