[Doctor Mark]

I've come across a product for "neutralising" formaldehyde, such that it can be tipped down the sink. It says that the active ingredient is phosphoric acid (5%).

My organic chemistry isn't too flash, but I'm unable to see how H3PO4 will react with the HCHO - or will it just oxidise it to the (non-carcinogenic) formic acid which can then be diluted and discarded?

Thanks in advance
Mark

[nj_bartel]

I don't think phosphate is a particularly strong oxidizing agent... Formaldehyde will undergo equilibration in even neutral water though to yield mostly the acetal though.

[Doctor Mark]

Thanks but I'm not sure I understand (even after Googling acetal).
Are you saying that the oxygen gets protonated and the pi-bond transfers its electron density to the oxygen thus creating HCH(+)-OH?

[nj_bartel]

 http://chemistry2.csudh.edu/rpendarvis/hemiacetal.html

I meant hemiacetal, sorry.  It's a structure that would only exist in solution though, so I'm not sure it would really take away from formaldehyde's toxicity.