Jor
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Formaldehyde
I have a liter of 6% formaldehyde here. It is standing in the way so I figured out I have 3 options:
-Trying to concentrate it, to 37%. I think this should be possible by simply boiling the solution, but when looking at the boiling point of
formaldehyde (wikipedia) I see 95C, so the gas doesn't simply boil away like when heating ammonia, but the 37% solution seems to be some sort of
azeotrope?
-Convert the formalin to paraformaldehyde, and generate CH2O when needed. How can I effectively convert it to paraformaldehyde?
-Bring it to a waste processing facility. The stuff is so cheap that this might be better than all the hassle, but I'm not sure yet.
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Joauml
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You could make some hexamine if necessary
people can buy gunpowder without questions, but if I buy glycerin, people ask me if I'm going to make a bomb.
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Jor
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I already have plenty of hexamine, and I never use it, so I don't need to make more to be honest.
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entropy51
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Jor, this old thread has a couple of references that probably have the information you're looking for. There is also a whole book on HCHO in the forum library,
I believe.
Better to remain silent and appear a fool than to open your mouth and remove all doubt.
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ChrisWhewell
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I'd be inclined to keep it on hand for silvering glass per Brashear's method, or else oxidize it to formic or a formate salt for later use in reducing
platinum group metals from solution.
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JohnWW
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That 6% solution of formaldehyde may be about what embalmers in funeral homes use for embalming bodies, by replacing all the blood. However, it is
definitely much weaker than the "formalin" used for preserving biological specimens in, which is 40% formaldehyde.
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Panache
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Mood: Instead of being my deliverance, she had a resemblance to a Kat named Frankenstein
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It condenses at -21C, so you could condense the gas over a dry ice cold finger, then dilute it down accurately to 37%. Either way i'd somehow keep it
if possible its getting quite rarer these days, although its not difficult to make.
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entropy51
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| Quote: | | However, it is definitely much weaker than the "formalin" used for preserving biological specimens in, which is 40% formaldehyde
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No, John, 40% is usually diluted to about 4% for fixing and preserving biological specimens.
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Klute
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The best way of making paraformaldehyde is to distill formalin solutions under vaccum until take off nearly stops, then pourin g the thick residu onto
a cold pyrex dish and breaking up the gummy solid that forms. Be carefull to not let it settle in the distillation flask as it makes a very hard solid
when cold, and you will not be able to scrap it out (beleive me, I broke a flask trying to  )
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
-Alice Parr
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