Sciencemadness Discussion Board

Mannich reactions with sulfur

Chisholm - 15-6-2017 at 04:44

So I'm studying condensation reactions such as the formation of hexamine, and have come across an interesting subclass wherein one or more of the nitrogen atoms is replaced with a heteroatom or heteroatom-based substituent group.

Instead of a 3:2 molar ratio of formaldehyde to ammonia, a 2:1 molar ratio of formaldehyde to sulfamide— H2N-SO2-NH2 —produces this condensation product:

This condensation takes place in acidic conditions rather than alkaline; I'm under the impression that alkaline conditions result in a long polymer rather than a cage.

Unlike sulfamic acid, however, sulfamide isn't readily available to the amateur, and the standard preparation method (mixing sulfuryl chloride and anhydrous ammonia) is beyond the reach of amateurs.

Would it be possible to, say, combine sodium sulfite, an acidic ammonium salt (such as the hydrochloride), and 37% formaldehyde to generate this compound in one pot?

Cryolite. - 15-6-2017 at 09:00

That compound is a violent toxin, a couple orders of magnitude more toxic than cyanide...

Metacelsus - 15-6-2017 at 09:40

Really, making that compound is a bad idea. Don't say you haven't been warned.

In any case, I would expect formaldehyde + ammonium chloride + a sulfite salt to produce mostly hexamine. I can't think of any plausible mechanism for the sulfite to become involved.

Ozone - 15-6-2017 at 17:59

Yeah, TETS. I would recommend avoiding it. See the "no antidote" part.