CobaltChloride
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Phthalic anhydride from naphthalene
I've recently found a moth repelling product which explicitly states that it is 80% naphthalene and 15% anti agglomeration agent. After
recrystallization from ethanol, the product became crystalline. I've noticed that the science madness wiki lists "making phthalic anhydride" in the
projects section of the naphthalene page. What is the process involved in this synthesis? It would be nice to not have to make it from gloves.
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JJay
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You can oxidize naphthalene to phthalic acid with permanganate. This is usually performed in an acid medium. There are several papers on this topic
that you can easily locate. I don't know what the anti-agglomeration agent would be (talc, silicon dioxide, wax, ???).
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battoussai114
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Industrially the oxidizer is oxygen over a transition metal oxide catalyst. I remember reading about it a while back and, IIRC, the better performing
ones where Vanadium followed by Molybdenum oxide. I'm out of my house right now, as soon as I get back I'll try to upload some papers I probably have
on my external HD.
Batoussai.
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CobaltChloride
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Quote: Originally posted by JJay  | | You can oxidize naphthalene to phthalic acid with permanganate. This is usually performed in an acid medium. There are several papers on this topic
that you can easily locate. I don't know what the anti-agglomeration agent would be (talc, silicon dioxide, wax, ???). |
I don't know what it is, but it doesn't seem to be soluble in boiling ethanol. Doing a hot filtration was enough to remove it. The recrystallization
should've also removed the 5% which is unaccounted for because it is, most probably, composed of related hydrocarbons.
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Magpie
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Here's an easy way to make it from phthalic acid:
https://www.sciencemadness.org/whisper/viewthread.php?tid=25...
The single most important condition for a successful synthesis is good mixing - Nicodem
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CobaltChloride
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I know the reaction conditions, but thank you for providing me with the exact procedure.
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Foeskes
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There are lots of videoes on making it from xylene. The procedure should be similar. I think making it from napthalene uses quite a lot of
permanganate for a low amount. Maybe xylene is better(I haven't done any calculations yet.
Either way you need to be a bit careful permanganates are really strong oxidizers and if you're not careful it can oxidize your products to CO2 and
H2O decreasing yield.
[Edited on 25-3-2018 by Foeskes]
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CobaltChloride
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I am quite new to the world of organic chemistry, so that's why I wanted an exact procedure (papers on the subject don't seem to give one). The
stoichiometry is 1:4 naphthalene:permanganate according to this paper: https://jchps.com/issues/Volume%2010_Issue%201/40-0581116.pd... . For me, xylene isn't very easy to get (I need to do a fractional distillation of
a paint thinner and a lot of azeotropes with xylene are formed, thus decreasing yield significantly).
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