[Albert G.]

Hello All!

I had a question surrounding the conversion of H2SO3 to something benign and useful: sodium sulphite (Na2SO3).

Theoretically, from what I do understand, the process would proceed thusly:

1)  Make a fuss in some water: Na2O + H2O ---> 2NaOH

2)  Scrub some sulfur dioxide into the above: H2SO3 + 2NaOH ---> 2H2O + Na2SO3

Is this correct?  Would it work?

Of course, the fuss would be considerably reduced in step 1) if we could just use plain old lye (NaOH) in place of the sodium oxide to make the necessary 2NaOH.  That doesn’t look like it would work; as we'd wind up with sodium bisulfite which would release the sulfur dioxide gas once again in the presence of the H2O.

Is there a simpler alternative to the inclusion of neat Na2O which might work reasonably well here?

Provided that the process wasn't hazardous (and didn't cost an arm and a leg), it might be an interesting avenue for scrubbing sulfur dioxide from some of those many smokestacks out there...

Food (preservative:1eye:) for thought???

[eugenedakin]

Hello Albert,

In the answer to the following portion of your question:

I had a question surrounding the conversion of H2SO3 to something benign and useful: sodium sulphite (Na2SO3).

Theoretically, from what I do understand, the process would proceed thusly:

1)  Make a fuss in some water: Na2O + H2O ---> 2NaOH

2)  Scrub some sulfur dioxide into the above: H2SO3 + 2NaOH ---> 2H2O + >Na2SO3

Is this correct?  Would it work?

Yes it is correct, and it would work.

On the second portion of your question:

Of course, the fuss would be considerably reduced in step 1) if we could just use plain old lye (NaOH) in place of the sodium oxide to make the necessary 2NaOH.  That doesn’t look like it would work; as we'd wind up with sodium bisulfite which would release the sulfur dioxide gas once again in the presence of the H2O.

Sodium bisulfite is usually made with sodium carbonate in solution which is saturated with sulphur dioxide.  If sodium sulphite or sodium bisulphite remained in solution, and no excess sulphur dioxide existed, sulphur dioxide would not be created, but would oxidize atmospheric and dissolved oxygen to form sodium sulphate (this reaction happens relatively quickly).

I hope this helps,

Sincerely,

Eugene