Sciencemadness Discussion Board

Picric Acid and the Mystery of the Red Goo

madscientist - 20-6-2002 at 19:23

Today I attempted to prepare picric acid. I used non-purified aspirin tablets. Each contained 0.325g of acetylsalicylic acid. Each also contained 0.025g of starch and dicalcium phosphate.

I warmed 125mL of 94% H2SO4 in a beaker to 60C, and added 88 aspirin tablets. I then began to add about 2g of NaNO3 per minute, stirring rapidly the entire time. I added a total of 51g of NaNO3. A few minutes after the addition of the final scoop of NaNO3, I let the contents of the beaker to cool down to 40C. There was a reddish foam in the beaker. I dumped the contents of the beaker into 300mL of cold water. Some picric acid precipitated, but when the red foam was stirred, it formed a glob of red goo. This "goo" was not water soluble, and had no attraction for glass. When removed and placed in a separate beaker, and then squeezing out the air bubbles, it slowly became a foam again! I'm wondering what the hell that stuff is. Any ideas?

(edited to add) It's not just a small amount of red "goo"; there's probably around 10g. It boils before igniting; it burns gently, and not easily. It leaves a lot of carbon when burned.

[Edited on 21-6-2002 by madscientist]

plasma - 21-6-2002 at 13:26

Maybe the binder got polymerized and burns becuse the starch got nitrated ? (Or maybe not)

BTW, Why didn't you purify the tablets before making the picric acid

madscientist - 21-6-2002 at 13:49

Well, a total of 2.2g of binder - the binder being composed of starch and dicalcium phosphate - shouldn't have such a catastrophic effect on the reaction. :)

By the way, I'm hearing that others have also gotten the red "goo" from using a method similar to mine (mine was based off of Mr Cool's method). I hear also that some have gotten the red "goo" from using too much potassium/sodium nitrate.

plasma - 21-6-2002 at 14:42

Maybe you will have more luck with the synthesis at Powerlabs
http://www.powerlabs.org/chemlabs/picric.htm

Madog - 21-6-2002 at 20:03

I also got the Red Goo!!! i have gotten it with Mr. Cool's method and the method in KIPE1. i think they may be the same if not realy similar methods. also, the TNP that i did get was realy dark red brownish in both cases. i think ill chuck it.

in fact, the method that i had the best luck with so far was mega's, i used 10 asprin 70ml H2SO4 and 9g KNO3. i got a kinda good yield. i htink i also did this with 50ml of H2SO4, i cant remeber witch got the best yield though. one was about 4-5g the other was like 1g. i will use his mrthod next.

edit: oh yeah, when i did Mr Cool's procedure i pureified the asprin and i still got this crap.

[Edited on 6/22/02 by Madog]

Madog - 24-6-2002 at 08:51

i am halfway through megas method, i adjusted it a bit so it uses 500ml H2SO4 instead of 700. but im just doing a 10 asprin test batch so im using 50ml.

i used 9g NaNO3

it looks REALY good. after i nitrated it it lookes yellow/red as opose to black which is GOOD. i am letting it cool. i will precipitate in a couple minutes and let you know how it goes. :)

BrAiNFeVeR - 7-7-2002 at 13:30

I'm really interested in this HE too, so I'll join the experiments. for now I'll follow madog's suggested method, but if you want a second opinion on an other method, I might just try that one too :-)

sorry

Madog - 7-7-2002 at 18:30

im sorry but i negleted to tell u how it whent. it whent SHIT!!

i got a tiny bit of crap!

i think ALEN's method may be good...

BrAiNFeVeR - 9-7-2002 at 08:25

Well, it certainly did not went "shit" with me !!

I used:
- 5 grams of ASA (10 purified 500 mg aspirine tablets)
- 70 ml H2SO4
- 10 grams of KNO3

The reason I used 10 grams of KNO3 is because mega's method stated I should use 90 grams of NaNO3 OR KNO3 (thus making no diffirence between them) while NaNO3 has a considerable higher amount of the nitrate group per weight then KNO3.
I couldn't be bothered to calculate the correct amount of KNO3, so I rounded it of to 10 grams.

I'll post yields when product is dried, but I can say it looks good :D

TNP?

Nils - 10-7-2002 at 08:54

the red stuff is proboubly DNP(Dinitrophenol or even Mononitrophenol).

By the way, my TNP was yellow, but yesterday i've tried it again(for making DDNP, with succes! Very good primair) and it was Yellow! But after boiling it in water it becomed Yellow(let the water evaporize as it is very soluble in it)

anyway, it tooked a few times until my TNP worked. Just try again, and try again.....

By the way, i'm mr.evil from teh E&W forum(NO i'm not banned)

BrAiNFeVeR - 17-7-2002 at 04:45

I finally got around to purifying and drying my TNP.

Since the filter paper that it was drying on was starting to decompose, I lost a cosiderable amount of TNP I think.

What I heve left now is a bit more then 3 grams, wich is no great yield at all.

But I will try again, and optimise yields as much as I can this time !!
Also, on this occasion, I didn't see any of the mistery red goo.

So I'll try the use exact same method :D

madscientist - 27-7-2002 at 21:49

I think that the Red Shit is actually picric acid anhydride. That would explain all of its properties - it's being insoluble in water, its tendency to slowly form picric acid when in contact with water, its waxy/gooey nature, everything...

kingspaz - 28-7-2002 at 03:19

have you tried detonating the goo? if it detonates then atleast you know its a nitrated compound.

Nils - 31-7-2002 at 03:56

No i didn't tried to detonate it, but it won't even burn! Next time when i'm making TNP i will use Phenol(as i have 300grams of it 8)

btw, don't get any phenol compounds on your hands, it will be yellow for days. Not to speak about the TNP toxicity.

kingspaz - 31-7-2002 at 04:32

nils, TNP is toxic but its not THAT toxic. i thought the most of the toxicity is casued by the phenol group. i also remember reading the LD50 was 2g but i could be wrong about that.

kingspaz - 31-7-2002 at 04:34

dammit, why can't i edit my posts?
also if it doesn't burn then its not a nitrated compound.

About the non-editability...

Polverone - 31-7-2002 at 09:35

I'm not sure why people can't edit their posts. Even moderators can't. If I want to edit something I have to change the database entries by hand. My conclusion is that "something is screwed up" but I don't want to switch or reinstall software because we've done that too much already. Sorry, I know it's a pain.

Madog - 29-8-2002 at 10:35

today i did brainfevers method useing 10grams of unpureified asprin powder(i dont think its worth pureifying) 20grams of NaNO3(what was lyeing around) 140ml 935 H2SO4. i also heated the ASA/H2SO4 to disolve it easier and after it was mostly disolved i took it off. then i waited a little while to let it convert to phenol and cool a bit. then i added the NaNO3 in 4 parts. the whole process and cleanup took around 37 minutes, not bad

it worked GREAT! the TNP looks SUPER pure and the yeild is good! i will wigh it when dry.

PHILOU Zrealone - 9-9-2002 at 14:31

I already answered the red picric acid question elsewere in this forum!

By the way you may end with mononitrophenol and dinitrophenol too if the nitratation is not efficient enough (enough HNO3/H2SO4 at a strong enough conc).
DNP is explosive too and also makes explosives primary heavy metal salts; they are just less powerful than TNP and TNP salts!

I can tell because I have pure paranitrophenol (4nitrophenol) and (2,4 dinitrophenol) and TNP (2,4,6) that they all looks the same!
Cristalline yellow, colourising everything in yellow!

PH Z
:cool:

madscientist - 12-9-2002 at 18:45

I just carried out a pretty poorly executed experiment, but it may prove to have interesting results. I dumped 26g of acetylsalicylic acid into 50mL of mixed acid (it had absorbed a little moisture from the air). I stirred it, and kept the temperature below 30C for two hours. Intensely violet crystals were on the sides of the beaker. I then dumped in 200mL of ice water. A huge amount of a purplish-brown precipitate formed. I'm wondering if that is something like a nitrosalicylic acid - the acetate group on acetylsalicylic acid should have no trouble being removed (addition evidence for that case: I smelled a substantial quantity of acetic acid).

madscientist - 16-9-2002 at 14:49

I cooled down the sludge to 6C, and filtered it. Here's a photo.

2,4,6-tnp

BLAST_X - 30-9-2002 at 11:45

Here some attributes to picric acid.

advantage:
- good density, ~ 1,8 g/ml
- high vod, ~ 7400 m/s
- high yield with all different synthesis-methods

disadvantage:
- small volume of gas, ~ 345 ml/g
- chemicals to synthesizing picric acid
are expensive (phenol, benzene)
- tnp are toxic (can be resorbed by skin)
- high dissolubility in H2O
- somewhat sensitive to friction, heat and shock

I think,
picric acid is a better smoker-powder when not purify correctly or produced
by H2SO4/KNO3-method.

BLAST_X - 1-10-2002 at 05:25

In a pollutes condition it`s a better flash propellant. Produced by H2SO4/KNO3-method, the product have a very bad quality than produced by Phenol.
On the open air, 2,4,6-tnp burns only with high temperature when it lighted.
It can be detonated when strongly heated at high density or under pressure
without the presence of O2.
With a vod of ~ 7400 m/s, 2,4,6-tnp can be used as a second primary explosive in a detonater to set off insensitive high secondary explosives or in a blasting cap ignited by a primary explosive.
2,4,6-tnp have a high reactivity with many other chemicals. Therefore, it`s sometimes dangerous when 2,4,6-tnp form picrates by reacting with metals ...
It can be used to synthesize other less dangerous explosives.
(ammonium picrate)
2,4,6-tnp are used in labs too,
to synthesize many substances or other benzene-compounds.

BLAST_X - 1-10-2002 at 14:45

I mean smoke-powder.
With 2,4,6-tnp in this cleanliness, you can
create more smoke than other more.
I suppose, picric acid can be easy synthesized with salicylic acid by a 3-step reaction in one, by adding SA to a mixture of H2SO4/HNO3 and heating for a few hours.
I need looking for, to say the correct synthesis-way !

lead picrate

Loony - 28-10-2002 at 14:55

Probably the loudest explosion per unit mass must have been my lead picrate experiment. guaranteed to bring the neighbours (or the police) asking about your safety. Gently mix (not grind) lead oxide (forgotten which one, Probably PbO2) and picric acid. No more than 2 grams each please. Place in a crucible and gently heat over a low flame and stand or hide well back. The mixture melts and allegedly forms lead picrate. Continuation of heating causes an ear splitting detonation and the crucible may disappear. It seemed to take about 5 minutes, so do not approach whilst heating is continued.

Only to be performed by mad scientists. I would not advise anybody to try it, particularly with a weak heart.

Does anybody actually know the loudest explosion per gram?

Polverone - 28-10-2002 at 17:22

Loudest explosion per gram is quite a variable concept. Per gram of unconfined material? Per gram in thick cardboard tubing? Actual highest output of acoustic energy, or perceived loudest? After all, high explosives make a high "crack" that often seems less loud than the lower "boom" of pyrotechnic materials.

In other words, I doubt there are any hard and fast numbers for this sort of thing. You might as well ask which pyrotechnic formula is the most beautiful per gram.

Oh, and just FYI, if you're interested in discussing activities likely to bring concerned neighbors and/or agents of the law to your home, sciencemadness.org isn't the place to do it. This isn't Fingerless McPhee's Mad Bomber Knowledge Emporium.

Loony - 30-10-2002 at 06:07

Apologies if I am trangressing forum rules. I am new. No bad intentions or desire to upset neighbours. It was an experiment carried out at school and was surprisingly loud in adjacent classrooms. The material was unconfined on a shallow metal dish.

Polverone - 30-10-2002 at 09:13

No harm done. I just got the unfortunate first impression that you might not have very much regard for safety and responsibility. If this was a classroom demonstration, no problem.

PHILOU Zrealone - 5-3-2003 at 03:36

Picric acid can be made from any aromatic compound! If you are a good organochemist, have good synthesis pathway skills and common sense!

Benzen is expensive and phenol too!

Use vanilin from artificial flavoured suggar!
(HO)C6H4(-CH=O); no mather where the aldehyd group is in mixed acid it will oxydises and leave as CO2 upon heating!

Use toluen or xylen from synthetic lounge!
Mix with diluted KMnO4 to oxydise lateral alkylic chains; then add HCl and collect the unsoluble benzenic acids and diacids with ether or alcohol;dry the acids after evaporation of solvant; then add to 70% HNO3 and boil under reflux to get mononitrocompound and CO2 evolution; you should have nitrobenzene! Reduce with Fe/HCl or Sn/HCl or (NH4)2S to get aniline, diazotate it with NaNO2 (one without isolation from the previous batch and boil under reflux in ethanol...to get phenol!

Use paradichlorobenzen (used in pipirooms to give it a fresh smell or as antimoth)
Cl-C6H4-Cl + HNO3 -reflux and boil-> 1,4 dichloro 2 nitrobenzene!
Isolate and make it boil under reflux in saturated NaOH solution to get 4chloro2nitrophenol and 2nitropararesorcinol!
The 2nitropararesorcino might be obtained immediately by fusing the dichloronitrocompound in solid NaOH!

This later compound is interesting since:
HO-C6H3(NO2)-OH -HNO3/H2SO4->
O=C(C(NO2)=C(NO2))2C=O
and
HO-C6(NO2)4-OH
Both powerfull sensitive HE (over the TNP)!

PHILOU Zrealone - 5-3-2003 at 03:41

PbO2 is a form of Pb(4+)!
PbO2 + 4HO-C6H2(NO2)3 --> Pb(O-C6H2(NO2)3)4 + 2H2O

No doubt the salt exploded while heated!
The picrates must be done under no heating conditions by methathesis!
Na, K or NH4 picrates saturated solutions are allowed to react with concentrated nitrate salt of the desired compound!

Pb(NO3)2 + Na/K/NH4 picrate --> Pb(II) picrate precipitate + Na/K/NH4 nitrate!
Wash with clear water!
Never recristallise...you would get bigger cristalls if you are not experienced...thus stress in growing cristalls might induce detonation!

vulture - 7-4-2003 at 13:00

About the red goo, I found something interesting.

NO2 groups seem to color a substance red when they are connected through an oxygen atom instead of the usual nitrogen atom.

PHILOU Zrealone - 10-4-2003 at 05:10

QUote:
"posted on 9-9-2002 at 23:31
I already answered the red picric acid question elsewere in this forum!"

Answer is nitronic acid rearangement!

CH3-C(OH)=C(CH3)-NO2 <--> CH3-CO-CH(CH3)-NO2
CH3-CO-CH(CH3)-NO2 <-OH(-)-> CH3-CO-C(CH3)=N(O)-OH
Thus beta nitro enols undergo enol-ceton equilibrium to provide a alfa hydrogenated nitro derivative in tiny % that gives the yellow colour; the later upon the action of a base undergo the nitronic rearangement
cf NM:
CH3-NO2 + NaOH --> CH2-NO2(-) + Na(+) --> CH2=N(O)-ONa
The later compound is deep orange to deep red-brown!

:cool:

shadeT - 7-8-2003 at 05:24

i found this method of making picric acid : 2 grams ASA , 10 ml H2SO4 and 4 grams of KNO3 . is this method OK ???? i didn't made large amounts. i did just how it said in the procedure . it was ok , but i don't know about the yield ... i did some search on the net and found that the theoretical yield should be 80% . my TNP is still in ice water . today i'm going't to let it outside to dry out . i was meaning to put TNP in a small plastic bag so that it doesn't form picrates and than in a film carnister and then a electric detonator ... maybe this could be the safest detonation , what about the storage . i searched and i found that the safest method is to disolve it in water and so to store . is this all ok ? thanks ! :cool:
here is a picture of TNP in ice water after the procedure ::

Image85.bmp - 297kB

chemoleo - 8-8-2003 at 04:34

I think I read somewhere that the incorrect making of TNP results in the formation of polynitrophenol compounds, with no specific composition, which then forms the alleged red goo.... try it, it burns!

Picric acid (TNP) & AN

IgnorantlyIntelligent - 21-1-2004 at 06:02

Instead of making a new topic, it would probably be best to post here in this old topic. I was wondering, given TNPs high VOD and good brisance could it be a good choice for something to be mixed with powdered/dried AN in charges weighing under 1 pound and with a ratio of about 2:1 AN:TNP. I guess my question is is there any chance that TNP could react to the AN in a bad way? NG and almost all other nitrates behave fine and are used frequently with AN as a sensitizer but I never hear much about TNP/AN.
PTN used to be used as a commercial booster for many years and commercial boosters are up to 1lb in weight so I would imagin it to be safe.

[Edited on 21-1-2004 by IgnorantlyIntelligent]

[Edited on 21-1-2004 by IgnorantlyIntelligent]

guaguanco - 21-1-2004 at 12:12

If I were going to try making picric acid from asprin, I'd first isolate pure salicylic acid (dil. NaOH, filtration, alkaline hydrolysis, reacidification, filtration, recrystallization). Then perform a nitration of pure salicylic acid following a tested recipe. There a variety of binders that might be in the tablet, and nitration of the mixture will make it much harder to get a pure product in decent yield. (The red glop people are getting probably has at least half-a-dozen different reaction products in it.)
Pure picric acid is a nice yellow crystalline material that's not a great explosive in itself. Picrate salts are easily prepared since picric acid is a pretty strong acid.
Pure products require pure starting materials.

Polverone - 21-1-2004 at 12:27

Most people do purify their aspirin tablets to isolate crystalline material first. Hot acetone works great, though it's hard to finish the filtration before crystallization takes over if you're trying to gravity filter. When I nitrated acetylsalicylic acid isolated in this fashion, using sulfuric acid and potassium nitrate, I was able to recover beautiful canary-yellow crystals that stained everything they touched, formed salts with alkali carbonates with evolution of CO2, and otherwise behaved as I would expect picric acid to. I never saw any "red goo." However, I didn't have a pure reference sample of TNP to compare with, and it's quite possible that I had lower-nitrated phenols in there also. It would interesting to repeat this experiment and run TLC on the product.

Madscientist was of course just begging for trouble by not bothering to purify his starting materials at all.

guaguanco - 21-1-2004 at 12:57

Quote:
Originally posted by Polverone
Most people do purify their aspirin tablets to isolate crystalline material first. Hot acetone works great, though it's hard to finish the filtration before crystallization takes over if you're trying to gravity filter. When I nitrated acetylsalicylic acid isolated in this fashion, using sulfuric acid and potassium nitrate, I was able to recover beautiful canary-yellow crystals that stained everything they touched, formed salts with alkali carbonates with evolution of CO2, and otherwise behaved as I would expect picric acid to. I never saw any "red goo." However, I didn't have a pure reference sample of TNP to compare with, and it's quite possible that I had lower-nitrated phenols in there also. It would interesting to repeat this experiment and run TLC on the product.

That all sounds spot-on! Why can't more people be like you?:cool:

Mumbles - 21-1-2004 at 14:33

Picric and AN mixed would probably for some Ammonium Picrate. This would ad to the mixture's sensitivity, but most likely not enough to make it extremely dangerously sensitive or anything. It might even come in handy if you theoretically decide to test the mix out.

I also don't know how strong of a base(or if it even is one at all) AN is. IMO some Ammonium Picrate would form regardless.

Chemical Peach - 22-1-2004 at 11:06

Reaction time/heating

I am not familiar with all the syntheses people refer to in all their detail, but it seems to me that people do not heat for very long periods, if any at all, inyour procedures for TNP, if i remeber correctly in 'advanced practical organic chemistry' for example the procudure call for the phenol (/phenol derivative) to be heated with the sulphuric acid to fully form phenol sulphonic acid before introduction of the nitrate (be it HNO3, XNO3 etc). The synthesis i'm refering too also calling for the reaction to be held at around 100C for 1 1/2 hours for the reaction to complete fully. Possibly you are all aware of this and know of a reason why it is unecessary, but as many of you refer to disapointing yeilds, this may be a contributing factor.

I have not carried out this synthesis for a while and do not remember and specifics of results, but i may attempt it soon and will be sure to post information here that could be useful.

pete

sylla - 22-1-2004 at 12:46

Have some of you tried to make Picric Acid from different chemicals (instead of ASA/SSA) such as silk ?

chemoleo - 22-1-2004 at 12:57

Rofl :)
Silk is protein. The only amino acids that have somethng that resembles a phenol group is phenylalanine and tyrosine. So the yield is definitely not going to be high, only 2 out of 20 amino acids. First destruction of peptide bonds with HCl at high temp for several hours, then, possibly destructive sulphonication. Maybe you have some luck there... maybe ;)
A better one is indigo, a dye that you can get freely. I think with NaOH (I once did it a long time ago) you get sodiumphenolate...

sylla - 24-1-2004 at 02:07

"other early experimenters obtained picric acid by nitrating various substances such as silk, natural resin, etc ..." They also talk about wool or horn and indigo.

That's written in J. Akhavan's chemistry of explosives.

So I was wondering if somebody tried it

A brief OT about EBW dets

Blackhawk - 25-1-2004 at 02:58

I have recently gotten some promising results with my explosive bridge wire detonator and after reading a lot of accident reports I want to study high explosives without the danger of organic peroxide detonators. Most people I see use Manitol Hexanitrate or PETN in their EBW caps, unfortunately these synthetic sugars are hard to get, Asprin or Oil of Wintergreen seem like a better bet.

My question is that could I use straight TNP or one of it's alkali metal derivatives in an EBW cap, I have not found much on the impact energy in Joules needed to innitiate them so any info you would have would be a great help.

The_Davster - 25-1-2004 at 14:03

potassium picrate
http://www.powerlabs.org/chemlabs/potassium_picrate.htm

I believe that it is more sensitive than picric acid, however it doesent seem to be easily detonated.

[Edited on 25-1-2004 by rogue chemist]

KABOOOM(pyrojustforfun) - 30-1-2004 at 14:00

<blockquote>quote:<hr>Picric and AN mixed would probably for some Ammonium Picrate. This would ad to the mixture's sensitivity, but most likely not enough to make it extremely dangerously sensitive or anything<hr></blockquote>
no nitric is a hell lot more acidic than picric acid. plus the specific character of ammonium picrate is its high <b>in</b>sensitivity

tom haggen - 28-3-2004 at 18:54

I was under the impression that ammonium picrate was an insensitive energetic compound. Thats what it says in megalomania's chemlab. Also NH4NO3 does not have a lower ph level than picric acid, I have found that NH4NO3 when you add NH4NO3 to a ph tester it hardly changes the color. Not to say that I would want to store NH4NO3 in a metal container for long periods of time.
EDIT: oh duh kaboom said it was insensitive.
[Edited on 29-3-2004 by tom haggen]

[Edited on 29-3-2004 by tom haggen]

halogen - 18-4-2004 at 05:12

If your trying to make picric acid, I think a good way would be to start with p-cresol or beta-nitrostyrene. Use hydroxylamine to put on some NH2 groups and oxidize it with caro's acid. If that doesnt work, soak it in nitric acid. It's not picric acid, but it might be worth trying...

PS: The oxygen that links the two major rings in sucrose can be oxidized to peroxide. Once youve done that, Thake advantage of all the hydroxyl groups. Pump it up with nitric acid!!!
Its really worth it!:D

Quince - 21-7-2005 at 22:46

Quote:
Originally posted by halogen
PS: The oxygen that links the two major rings in sucrose can be oxidized to peroxide. Once youve done that, Thake advantage of all the hydroxyl groups. Pump it up with nitric acid!!!
Its really worth it!:D

Can anyone confirm this? Have you tried it? How would you go about this oxidation without burning up the sucrose?

GTOzoom - 9-5-2008 at 11:01

I was wondering if it is possible to make picric acid via sulfuric acid and ammonium nitrate instead of potassium nitrate. I remember reading about it on roguesci a while back but the forums are currently undergoing maintenance and i can't seem to find any information elsewhere.

thanks for the time!

zeppelin69 - 9-5-2008 at 15:20

I can't think of any nitrations where ammonium nitrate is not a suitable subsitute for alkali nitrates. In fact, in nearly every case that I can think of, it is better. The only time I would use an alkali salt over AN is for distilling nitric without a vacuum, but thats another thread...

Rosco Bodine - 10-5-2008 at 00:14

What you think doesn't square with experimental results for nitrations of a particular precursor like aspirin
anyway. For whatever reason ammonium nitrate does not seem to be as good as either potassium nitrate or sodium nitrate in the nitrating activity with sulfuric acid on aspirin. The same results apply to entirely different nitrations. For whatever reasons, certain combinations of a particular nitrate with sulfuric acid will be found to work better for nitration of a particular precursor to produce a particular end result and the yield and purity can vary significantly depending on whether you are using the optimum combination and nitration conditions or not. But there definitely isn't any correct generalization that ammonium nitrate is an equivalent or superior substitute for an alkali nitrate in nitrations in general which simply don't lend themselves to such generalizations. Experiments will show you that the combinations of reactants and ratios and conditions just aren't so general as to fulfill that expectation it should make no difference. Chart some experimental nitration results and you will see this is true, in contrast with your theory as to what should occur.

zeppelin69 - 10-5-2008 at 12:26

If you have any of these charts I'd very much like to see them, they sound interesting. If you don't have charts, could you at least post the data you are basing this on?