subsecret
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1-Nitronaphthalene Residues: Need a good solvent.
So, I decided to make 1-nitronaphthalene as follows:
20 mL concentrated HNO3 and 20 mL concentrated H2SO4 are mixed and cooled on an ice bath. 25 g fine naphthalene is
added slowly, keeping the temperature between 45-50 degrees (which isn't difficult to do in this synth). After this, the material is kept between
55-60 degrees for 30 minutes, and then cooled. Upon cooling, the organic product forms an orange paste which doesn't like to dissolve, but is very
sticky. This is washed with water several times, which is decanted off. This is mixed with hot ethanol until dissolved to an orange solution, and left
to cool. A yellow precipitate forms, which I expect is the 1-nitronaphthalene. I have not filtered it yet, and a recrystallization will be done from
ethanol once I get the goo off my funnel.
So, the synthesis turned out well, but the residue is hard to clean up. Hot ethanol dissolves it, but cold ethanol only seems to dissolve the orange
impurities, leaving a hard, white cake behind. I've tried petroleum ether as well as hot water, and water dissolves the residue over time. The problem
is that hot water is impractical without washing large amounts of the organics down the drain, which I don't really want to do, as I'm on a septic
tank and these are sensitive. The MSDS for 1-nitronaphthalene only says that it is a mutagen (it sticks to hands, in case you didn't know), and that
ecological information is not conclusive.
Any help in finding a good solvent for the residue would be very appreciated.
PS: the procedure comes from Vogel's p. organic chemistry. Use excess acids and forego the steam distillation.
Fear is what you get when caution wasn't enough.
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Molecular Manipulations
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First use cold EtOH to dissolve the impurities. Then use chloroform, or carbon disulfide to dissolve your nitronaphtalene. It's quite soluble in both
(according to Sigma). Recrystalized a few times in the same.
-The manipulator
We are all here on earth to help others; what on earth the others are here for I don't know. -W. H. Auden
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PHILOU Zrealone
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1-nitronaphtalene or alfa-nitronaphtalene doesn't need strong HNO3 or H2SO4 to be obtained.
I got mine (orange-yellow wax with very deep penetrating smell) in decent yield from heating naphtalene and 69% HNO3 under 60W tungsten lamp.
With HNO3 and H2SO4 you may get dinitro, trinitro and tetranitronaphtalene!
The mononitro wax melt quite easily so you simply have to warm it up a bit and use common solvants!
PH Z (PHILOU Zrealone)
"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
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subsecret
Hazard to Others
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Thanks for the replies; I didn't know that Sigma had some solubility information.
I think that multiple nitrations occur when several nitrating baths are used in a row, collecting the intermediate product in between nitrations. I
imagine that some tetranitronaphthalene formed, but the vast majority was the mononitrated product.
Fear is what you get when caution wasn't enough.
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