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Author: Subject: Diethyl pthalate and various dyes from glowsticks?
aonomus
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[*] posted on 17-11-2009 at 22:25
Diethyl pthalate and various dyes from glowsticks?


So as a thought exercise of feasibility, I thought I'd post my idea here before ever trying it...

Glowsticks apparently use diethyl phthalate as a solvent, extraction could be done by distillation (impractical at 295degC unless under really low pressure), or by some sort of solvent extraction?

Byproducts would likely be phenol (I doubt whatever oxalate esters being used would survive heating much), and whatever dyes are left around.

For the dyes, I would think that for whatever portion of the glowstick unmixed reacts to UV (ie: contains the dye), a solvent extraction to pull the dye out might be feasible (granted, a poor way to get tiny tiny amounts of dye, but for small experiments its fine).

Any thoughts on whether recovering the diethyl phthalate is worth it?
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Alexein
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[*] posted on 19-11-2009 at 09:45


Glowsticks don't have diethyl phthalate. They have diethylhexyl phthalate since its cheaper for industrial scales. In addition they also have t-butyl alcohol for diluting the hydrogen peroxide.

but Most dialkyl phthalates work for the glowstick reactions, so you can find people using dimethyl, diethyl, dibutyl and diethylhexyl phthalates.

When i tried to do a vacuum distillation i was able to get the solvents but something weird happened with the dyes and they turned into a grey-brown non-fluorescent sludge in the distillation residue. Not sure what happened, but i didn't really investigate further since i was after the solvents.
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aonomus
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[*] posted on 19-11-2009 at 10:07


Hm, odd that the dyes would have turned into a sludge, perhaps a solvent extraction or run through a column to pull out the dyes before vacuum distillation?

Having diethylhexyl phthalate is almost as good as having diethyl phthalate, and being able to extract t-butyl alcohol would be nice too. The only reservation I'd have is distilling the peroxide/t-BuOH mix, I'd probably add some catalyst to decompose all the peroxide first...

Thanks for the info though, didn't know if I was right about the diethyl phthalate either.
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