Chisholm
Hazard to Self
Posts: 62
Registered: 2-4-2017
Member Is Offline
Mood: No Mood
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I have no idea what I just made
So my TNT odyssey continues. This time, though, I'm not quite sure what my product even is, though I have some guesses.
28 grams of p-toluenesulfonic acid monohydrate was dried by boiling it with 30 grams toluene to remove the water of hydration.
This was dissolved in 100 mL 98% sulfuric acid in a 500mL Erlenmeyer flask, and ~3 grams of phosphorus pentoxide was added, stirring until it had
completely dissolved. The resulting solution was blackish in color (similar to phenolsulfonic acid, but the color was weak enough that the solution
was transparent rather than an impenetrable black).
A mixed acid created by addition of approx 3.5 molar equivalents of NH4NO3 per mol p-TsOH (roughly 55 g) to 100 mL of 98% sulfuric acid was added,
slowly in portions at first, but when it became clear that adding the rest of the acid wouldn't raise the temperature beyond 35ºC, I dumped in the
rest of it. Stirring was maintained throughout.
Since I didn't have a Teflon stopper, I used aluminum foil tightly pressed over the lip of the flask to exclude water and contain any nitric acid
vapor.
I began heating and stirring on the hot plate, aiming for the 90-100º range for typical DNT formation. A reaction unquestionably occurred, as the
color changed from faintly brown to more of a lemonade color. However, the air in the flask slowly began to take on the brown tint of NO2. Worried
that the aromatic compound might be undergoing oxidation, I killed the heat after about thirty minutes while maintaining stirring until it was no
longer hot to the touch. I removed the aluminum foil cover and waved a paper fan to disperse the NO2, then sealed the flask with fresh foil.
I then left the flask undisturbed for several days, hoping to see layers separate or crystals form. This did not happen, nor did the color change
further or additional NO2 evolve.
Concluding that perhaps the yield of nitrated toluene derivative was small enough that it had entirely solubilized in the acid mixture, I decided to
end the experiment.
I poured about 30mL of the acid into 50mL water, and a whitish-yellow, almost foamy solid precipitated immediately. Small quantities of NO2 fumes were
briefly released, after which the solid became much whiter and denser.
However, the solid is water-soluble. Adding it to 1800 mL of hot H2O resulted in the eventual dissolution of the entire mass, producing a brilliant
yellow solution.
I performed some experiments with the specks that stuck to various lips and/or were left behind during decantation. The substance can be
recrystallized from hot water, in the form of an explosion of thin needles radiating from a central point, in a way virtually identical to the
substituted aromatics I've dealt with previously.
I have no idea what I really made. I'm trying to recover it from the quench solution by boiling it down. I have some thoughts:
Possible products, from most likely to least:
2-nitro-p-toluenesulfonic acid
4-sulfonylbenzoic acid
2-nitro-4-sulfonylbenzoic acid
4-nitrobenzoic acid
3-nitro-4-methylphenol
toluenyl 2,4-disulfonic acid
I'd bet anything that it is the 2-nitro derivative of p-TsOH. The water solubility indicates either a carboxylic acid group or a sulfonic acid group,
and the temperature never reached the level that would promote oxidation over substitution. Also, the evolution of brown fumes was gradual, while the
color change was fairly rapid, and if the oxidation of the methyl group were responsible for the color change, one would expect very copious evolution
of NO2. The reaction just didn't look like any runaway I've ever seen before.
I'm boiling down the quench solution, and hopefully can recover some of the product; if an immiscible organic layer appears I'll know the compound was
2-nitro-p-TsOH.
I'd really like a second opinion on all of this, though.
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PHILOU Zrealone
International Hazard
Posts: 2893
Registered: 20-5-2002
Location: Brussel
Member Is Offline
Mood: Bis-diazo-dinitro-hydroquinonic
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Into concentrated HNO3/H2SO4 (SO3/P2O5) nitroaromatics often display good solubility.
Since you have used a warm method...you may have dinitrocompounds like:
4-methyl-3,5-dinitro-sulfonic acid
2-methyl-3,5-dinitro-sulfonic acid
or trinitrocompounds:
2,4,6-trinitrotoluene
Oxydation of the methyl group is also possible see nitration of toluen into Green solution tread
The methyl group is oxydized via addition of HO-NO2 or HO-NO onto C=CH2 (quinonic resonance hybrid)
C=CH2 --> C(-OH)-CH2-N=O + C(-OH)-CH2-NO2
then
C=CH-N=O + C=CH-NO2 + H2O
and finally
C-CH2-N=O + C-CH2-NO2
The nitromethyl is then hydrolysed and oxydised into acidic media via hydroxamic acid into benzoic acid (via Victor Meyer reaction or transcient Nef reaction).
Alternatively the nitrosomethyl may be oxydized by HONO2 or by HONO into nitromethyl or hydrolysed to nitrated benzaldehyde and hydroxylamine...then
both oxydized by the oxydizing surrounding.
The nitromethyl may fix some nitrosonium to make nitrosonitromethyl and be further oxydized to geminal dinitromethyl or hydrolysed to nitrated benzoic
acid.
So in principle you may have 2,4-dinitro-benzoic or 2,6-dinitrobenzoic acid derivatives (maybe sulfonated into position 6 or 4)...and of course
trinitrobenzoic acid.
TNBenzoic acid looses its CO2 at boiling water temperature to make TNB which will loose its ability to form salts with Na2CO3.
Concentrated NaOH somehow solubilizes TNT and TNB via complex nitronate ways...so better avoid strong bases for identification.
[Edited on 22-4-2017 by PHILOU Zrealone]
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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