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Formaldehyde donors in solution
Does anyone have a link to an image or an explanation of how formaldehyde donor preservatives dissociate into formaldehyde?
Like DMDM Hydantoin + H2O —> Formaldehyde + DMDM Hydantoin ion
I was looking for this reaction but couldn’t find it.
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5 Replies
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No pic found
but these patents say
that in order to make DMDM hydantoin,
3,5 dimethyl hydrantoin reacts with paraformaldehyde (formaldehyde polymer)
so it makes sense to think that the reaction happens backwards too, to release formaldehyde.https://patentimages.storage.googleapis.com/5a/d5/80/ec85964d82b9a9/US5037843.pdf
https://patentimages.storage.googleapis.com/56/27/b9/ae65c945e2f9e0/US5616722.pdf
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@Gunther, yes in principle all the reactions that lead to/from DMDM hydantoin are reversible and under equilibrium. However, the hydrolysis of most formaldehyde releasers is slow at room temperature and at pH near-neutral. It becomes faster in strongly acidic or alkaline environment.
@Perry I’ve made this chemical drawing that you can use, if you still need.
There are two moles of formaldehyde released per 1 mole of DMDM hydantoin. The same reaction, more or less, happens for most other formaldehyde releasers, such as diazolidinyl urea and imidazolinidyl urea, or hydroxymethylglycinate.I can draw a detailed mechanism if needed to. Just let me know.
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@Imosca
Excellent! Just what I was looking for. Thanks!
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DMDM hydantoin has 2 times more 5,5 dimethyl hydantoin than actual formaldehyde.
5,5 dimethyl hydantoin 36.3%
Formaldehyde 17.39%Then how can it releases 2x formaldehyde per 5,5 dimethyl hydantoin when there is only 0.5x formaldehyde available per 5,5 dimethyl hydantoin in there?
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Abdullah said:DMDM hydantoin has 2 times more 5,5 dimethyl hydantoin than actual formaldehyde.
5,5 dimethyl hydantoin 36.3%
Formaldehyde 17.39%Then how can it releases 2x formaldehyde per 5,5 dimethyl hydantoin when there is only 0.5x formaldehyde available per 5,5 dimethyl hydantoin in there?
@Abdullah You need to make calculations in moles rather than in percentages or weight, since the reaction equations are expressed moles.
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