Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: caldwell on October 18, 2010, 05:43:39 PM
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Suppose I wanted to produce thiodiglycolic acid without killing myself from the accidental production of hydrogen sulfide gas. Would it be possible (and H2S-free) to do this by the very slow addition of monochloroacetate to an aqueous solution of sodium sulfide and then reflux it for a while?
Thanks!
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Still thinking this through…
So, Na2S + H2O -> 2Na+ plus SH- plus OH-
Now when excess Cl-CH3COO:Na is added, it will (should?) react with both SH- and OH- to (eventually) produce thiodiglycolate AND diglycolate.
Since I want to avoid producing diglycolic acid in favor of thiodiglycolic acid, and Na2S is also slightly soluble in alcohols, I was thinking that I should dissolve Na2S in ethanol and then add the Cl-CH3COO:Na. The product (thioglycolate and then thiodiglycolate) should be soluble in ethanol but at the same time the Na2S will be consumed slowly since it's only partially soluble in ethanol.
At first glance, this seems like a better way to avoid producing H2S or unnecessary glycolate. What do you think?
Thank you.
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It's inexpensive: $20/25g, $31/100g from Alfa.
Big-name suppliers: TCI, Acros, Alfa
Your plan might work, but including a good trap in your set-up is worth it.
Have you searched the lit for methods?
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Yeah, I know it's cheap to buy but my goal is complete synthesis of EDOT (3,4-ethylenedioxythiophene) from "scratch" - as a way to get my feet wet with hands-on chemistry.
Google Scholar didn't come up with much. I did find a patent for its synthesis, but it requires 250psi of H2S - which isn't in my league.