DDNP troubles

[Microtek]

OK I'm bringing this one up again because it seems to me that it is the perfect primary for the home chemist and the synthesis should be relatively easy.
Nevertheless, I have never succeeded in preparing it, in spite of endless attempts. I have tried the cookbook methods in KIBC, IPE and pyro2000 ( the one from swedish infomania ). I have tried the methods from The Chemistry of Powders and Explosives as well as Urbanski's method. I have also tried Stanfield's method which he posted in the old DDNP-topic. So far nothing has succeeded.

I start from picric acid which has been prepared from aspirin and recrystallized from water to remove the odd brown insoluble residue.
I then prepare the sodium sulphide solution by boiling equal amounts of sulfur and NaOH. So far no problems. Then I add picric acid to a solution of NaOH, this produces either a paste ( in stanfields method ) or a suspension ( in the cookbook methods - due to larger volumes of water ). Then I get to the point where it starts to go wrong: When I slowly add the sodium sulphide soln to the picric/NaOH soln I get almost no solid matter as most of it goes into solution ( when using all methods except stanfield's ). Picramic acid has a solubility of 1.4 grams per litre of water at 22 C, so I speculate that sodium picramate is actually produced instead.
I read in the Merck Index that picramic acid could be prepared from picric acid, conc ammonia soln, reduction ( with H2S I think ) and neutralization of the ammonium product with acetic acid. I also read that it could be used as an indicator of pH as it is red in alkaline media and yellow in acidic.
Based on this I hypothesized that it should be possible to add acetic acid to the filtrate after the reduction step and convert the sodium picramate to picramic acid which would then be easy to recover because of the low solubility.
There is in fact precipitated a lot of matter from the filtrate upon addition of acid and the colour is closer to yellow than to red, but I haven't gotten much further in my research at this point.

What I would like at this point is to benefit from the experiences of others who have attempted the DDNP synthesis. Especially things such as the smallest batch size you have tried and what grade of chems you have used. Mr Cool, your method would also be very welcome, as would an update of your homepage.
A final question: Can sodium cobalt nitrite ( Na3Co6(NO2)6 I think ) be used for diazotization? It's the only commercial nitrite I have.

[stanfield]

My DDNP works very well...
I coverted commercial picric acid (NOT HOMEMADE) into picramic acid (yes, sodium picramate !) then I coverted it to DDNP by a solution of commercial sodium nitrite (and not nitrAte like many said...)

In a open area, it burns rapidly but confined in my detonators with 1 gr of PETN it works pretty well...

I don't see where you're wrong...

But now, I have abandonned the DDNP since I have Sodium Azide. Yes lead azide is easy to prepare. For making DDNP you'll have to make Picric Acid then Picramic acid then finally, DDNP, it takes you many hours. I made lead azide just by adding 2 solutions and no ice bath is required, no heat is generated... Furthermore, the yield of Lead Azide is amazing, I filled up a big bottle in 4 synthesis... 20 gr of DDNP taked me 7 or 8 synthesis and many of them were failed because his synthesis isn't an easy task... there are many factor

Oh ! maybe, the only tips I can give to you is to make an ice bath with acetone (-10°C) Yes, the cold is maybe the main factor of DDNP production...

Sorry for my bad english, I'm speed up :)

<small>[ June 28, 2002, 08:56 AM: Message edited by: stanfield ]</small>

[Mr Cool]

Lol, yes, the webpage! Don't worry, I have lots of free time coming up in which I can do updates... starting in about two week's time. I might get some done before then though. Anyway...

D'oh! That sucks, I was sure I'd written up the DDNP procedure on my webpage. Oh well. A more detailed method will appear on my website soon, but here's a rough guide:
So, you add the sodium sulphide to the sodium picrate, I'm assuming you get the nice dark red colour? This is the sodium picramate in alkaline solution. I don't think I get any sodium picramate crystals at this stage, I can't remember now. Anyway, filter it to get out all the crap like sulphur, dust, bits of cement and the dead fly that happen to have landed in it. Maybe only I, with my messy-as-hell, falling-down "lab" have this problem, I don't know... wash a bit of hot water through the filter paper to get any picramate crystals that might be in there.
When you have a nice clear solution, I recommend letting it sit in a warm place for a few days to evapourate and get nice and strong. I'm sure you could boil off the water to make it a lot quicker, but this is the way I do it because I'm never in a hurry and I bet hot sodium picramate stains bad...
Add H2SO4 to this solution until its pH is somewhere around 2. This ensures you have picramic acid (a kind of camel-shit brown/yellow), as well as sodium sulphate of course.
Mix up your nitrite solution. I can't see why that crazy chemical you have wouldn't work, a nitrite ion is a nitrite ion no matter where it came from, right? Solubility might be a problem, I don't know. You'll have to do the math to get the right amount though, use a fairly big excess. 50% excess should hopefully be plenty. But it's better to waste nitrite that you just buy than picramic acid which you have to spend hours making.
Get you picramic acid mixture and your nitrite solution, and get them COLD. 0*C, or as cold as you can get it without all your solute ppting. The picramic acid should (hopefully) have ppted in the liquid before this point, when the H2SO4 was added. Now I can't remember which you add to which, I can't even remember if it matters, but add them SLOWLY and STIR. You'll still almost certainly get some NOx (= wasted nitrite), but hopefully not much. Just don't add it all at once like KIBC says, add it slowly, mix it well and keep it cold. Then I left it overnight, filtered, etc.
I will put up a full method on my website when I'm a little more level headed...

[viemane]

I have been wondering about how to make nitrit, I can´t find it commercially. It must be some way to convert for example NANO3 to NaN02, anyone who nows a way that works good.

I need a primary that sets of picricacid in a blasting caps, I thought that DDNP might be good, but I have also found information that Napicramate (maked by adding picricacid to NaOH in a solution, and filter) can be ignited with a fuse, is it strong enough and how much do I need to use in a blasting cap with picricacidd.

[Polverone]

The standard old fashioned preparation is to use metallic lead to reduce the fused nitrate to nitrite; NaNO3 + Pb = NaNO2 + PbO. I have tried this a couple of times and had very little success, probably because I cannot carefully control the temperature of my melt and NaNO2 decomposes not much above its melting point.

There are a few intersting alternate methods that I have not tried because I gave up and just bought the NaNO2. Have a look at US patents 572819, 595178, and 792215. I gleaned these from the Hive (www.the-hive-ws). You might want to go there and search for sodium nitrite since there are a number of threads about its preparation.

[viemane]

I wrote above about Na-TNP, it seems really good if it works.
The only incompatibleties I have heard is that it´s broken down by acids, but this will be no problem with TNP(picricacid:
TNP + Na-TNP &lt;==&gt; Na-TNP + TNP
But i have found wery little information about this compound.
Obviously it must have some drawback, beacuse it isn´t used that much, hopefully it just luck some brisance but is still strong enough to use in a blasting cap togheter with TNP.
Anyone ho knows more about it or about brisance, amount needed to set of TNP in a blastingcap (1g) or if it is safe to store.
I have heard sensitivity to be 18,6Nm (relative low) is this true?
It is also other intressting picrates, like Pb picrate...

[kingspaz]

ok...let me dig out the notes i made earlier....
i have been experimenting with alternatvie KNO2 syths and found one which seems to work better than the lead procedure.
right, i started thinking about why lead is chosen. the answer is its reasonably reactive and it melts at a low temperature creating a homogenous mixture with the molten KNO3 so the reaction can take place easier. i thought maybe using a more reactive metal would help the reaction occur since a more reactive metal would oxidise much more readily and therefore reduce the KNO3 more readily.
answer:

2Al + 3KNO3 ---&gt; Al2O3 + 3KNO2

27*2 = 54g Al
3(39+14+48) = 303g KNO3
= 2:11 Al/KNO3 - goes to 3:11 Al/KNO3 ensures almost all KNO3 used up making a purer product due to slight excess of Al to react with.

the Al must be in powderish form (not fin really, sure small chunks of foil would work) this provides a large surface area to react with.
the KNO3 should be mixed with the Al and then heated to about 340*C. basically hold the KNO3/Al mix at just above its melting point. this requires removing it periodically from the heat to control the temperature. it is critical the temperature doesn't rise above 350*C as that is the point at which KNO2 begins to decompose. KNO3 melts at 334*C so if you have accurate temperature control you can set it too 335*C. i heated my mixture for about 55 minutes. i can't promise this process works as i haven't tested the KNO2 in DDNP syth yet. i am fairly sure that i have made KNO2 as it dissolves instantanously in cold water where as KNO3 does not....its also a slight cream colour which is what i beleive is the correct colour for slightly impure KNO2.
to extract the KNO2 simple break the solidified block (after cooling) and add a little water. next bring to the boil and pass through a filter while still hot. next, evapourate the water from the filtrate and collect the crystals. should be reasonably pure KNO2.

[viemane]

Thank you Kingpaz, just the guy i had to speak with :)
i i use NaN03 or kN03 is not a big difference I think, NaN03 decomposes at 320C instead and melts before.
A problem is that I have hard to control the temperature, i don´t know if I dare to use the owen and it is also only up to 300C
The best had been to run it in the barbecue or something, but where do I find a thermometer for 350C?
100um Al is okay? I dont know what MESH, this is.
i found this in Hive, good, test this Kingpaz:
An aq. sol. of NaNO3 is neutral but a Aq. Sol. af NaNO2 is alkaline (App. pH 9) NaNO2 evolute brown fumes (N2O3) whith weak acid. NaNO3 do not.

[kingspaz]

thanks for that nitrite test. i'll test it tomorrow if i remember.
viemane, what you need is a petrol camping stove. i use one and it works great. it gets VERY hot VERY fast and is also cheap to run and reliable. i think a tin can on the end of a stick would work best. garden canes work well for holding things over flames so long as the flame doesn;t touch it. they only burn if the flame hits it but if not they are quite resistent to heat.
if you have any other small questions about the procedure (which i am carrying out on a larger scale tomrrow) then email me so as not to clog this thread with one line questions.

[mongo blongo]

I remember that I posted a LOT about this method including a good chem test to prove the XNO2 exists with Iron sulphate and vinegar. I suggest having a look at it but I can't remember what the thread was called sorry. <img border="0" title="" alt="[Frown]" src="frown.gif" />

[Microtek]

I remember that thread Mongo, I think it was called something along the lines of "Nitrate/Nitrite".

Knigspaz: Isn't this method rather dangerous ? Al/KNO3 is a flash composition right ?
I suppose that a molten mass might be too poor at propagating the flame throughout the mass, but still... Maybe you could increase safety by first melting the KNO3 and then stirring in the Al.

Mr Cool: Thanks for that post; that's the kind of response I was hoping for. How about your nitrite was that from a chem supplyer ?
BTW, I'm really looking forward to that update....

[Mr Cool]

I'm glad that post came out OK, I was a little bit drunk when I wrote it...

Yeah, I cheated and bought NaNO2 instead of making it. I've used TNP from aspirins and phenol, both have worked.
What's sodium cobalt nitrite used for? I'm very surprised you can find that and not NaNO2. I bet it's a lot more expensive, too. If you know of a furniture/antiques restorer, ask them if they know where to buy NaNO2. Apparently it's used for making metals look old/less shiny.

I think I'll do something on my website now, maybe just add some navigation aids and a recipe or two... but most things will have to wait a while.
I hope it's worth the wait!

[Microtek]

Sodium cobalt nitrite is used as an indicator for potassium according to Merck. It is not very poisonous as Na- or KNO2 is, and I got it from a lab depot where I taught for a while. The regulations around here means that I can buy many chemicals from a chem supplyer because I work freelance for a small R&D company. The thing is, this company solely does theoretical design work, so they don't need any chems at all - I just use their company status to be able to buy from the supplyer. However, if you want to buy chems that are marked as toxic or very toxic, you need a permit from some sort of health department.
This permit is routinely obtained by legitimate businesses, but I'm afraid that they need to see the work area, so I haven't applied.
Anyway, this means that I can buy pentaerythritol and other useful stuff, but no nitrite or sodium azide or phenol.

[Helos]

How poisounous are sodiumnitrite? it IS posiounos, but it´s used to salt meat so, it can´t be that badly really.

I have heard that sodiumnitrite has an limited storagetime, is this true? This is a very important question, if you do a large batch and half a year later you try to use it and all is fucked upp...

[kingspaz]

see, if its used to treat meat to keep it tender or whatever then how can it be terribly toxic? just out of interest KNO3 used to be used until it was found that this worked by bacteria breaking it down KNO2 which did the meat thing (my minds goin i can't remember exactly what it does!)
anyways, check these contrasting links:

<a href="http://www.biosci.ohio-state.edu/~jsmith/ChemMSDS/SODIUM%20NITRITE.html" target="_blank">http://www.biosci.ohio-state.edu/~jsmith/ChemMSDS/SODIUM%20NITRITE.html</a>

<a href="http://physchem.ox.ac.uk/MSDS/SO/sodium_nitrite.html" target="_blank">http://physchem.ox.ac.uk/MSDS/SO/sodium_nitrite.html</a>

i'm going to treat it as if it were KNO3. so basically don't eat it, try to avoid contact unless unavoidable and wash hands well after handling. speaking of KNO2, i've just finished a batch in which i'm expecting around 50-60g out of a possible 80g. i only heated it for 40 minutes but it solidified after 35 miutes. KNO2 melts at 420*C i think so most KNO3 must have been converted by this time.

microtek, i don't think the procedure is that dangerous as there is very little Al compared to the amount required for combustion. also i think so long as the temperature doesn't rise to the deomposition point of KNO3 or KNO2 then it should be ok as no oxidising gasses will be present. so you just need to heat until it only just melts then hold it around that temperature using the melting/solidifying as an approximation of 334*C. know what i mean?

<small>[ July 01, 2002, 06:39 PM: Message edited by: kingspaz ]</small>

[Helos]

Yes it was found out that KN03 could be turned into KN02 by some bacterias in small kids stomach. This poisoned them.
Iam pretty shure that I have read that meat were salted using NaNo2, but it could have been some other nitrite.
So... How posionous are nitrite?
And how stable is it, which is the product it decomposes in, and how fast?

[CyclonitePyro]

Some friends and I buy MRE's (Meal Ready to Eat) when we have a small outdoor party, so we don't have to worry about cooking food. The main course on every one contains sodium nitrite.

Most pork products have it too, hotdogs for one. It can't be that poisonous could it. There is a lot of shit in our food that is toxic, we just don't eat large quantities of it. Sodium Flouide is in some people's water, toothpaste, mouthwash and treatments at the dentist, and perhaps in milk, it is highly toxic. Wait, no...our friendly government says it's good for me.

[da man]

Mr Cool, would you mind posting the ratios of the chemicals used? I am planning on making some picramic acid, and eventually DDNP, from 22g of picric acid i recently made from aspirin, so i would greatly appreciate it if you posted the amounts you used for picramic acid. Also, what kind of yield did you get for the conversion of picric acid to picramic acid?
Thankyou for your help.

BTW, your site has picramic acid, and DDNP listed on the procedures list, but the procedure isn't actually written there!

<small>[ July 10, 2002, 03:37 AM: Message edited by: da man ]</small>

[Mr Cool]

I've just finished making a batch so that I can put up everything on my webpage (I had it all written down, but lost my notes :( ). It'll be written up later today with any luck.

I used the KIBC method but with slightly different ratios (mainly because my accurate scale has run out of battery, so I had to be a bit rougher), so 2g of NaOH and 9g of TNP, 8g of S and 8g of NaOH, I added conc. H2SO4 to the sodium picramate until it went light brown and then added 6mL more. I then filtered out the picramic acid, washed, dried and weighed it, but you don't have to do this. I added it to 200mL of water, and added 10mL of conc. H2SO4 and I used 10g of NaNO2, in a room-temperature almost saturated solution, just to make sure that there was enough.
The picramic acid doesn't seem very soluble (unless of course I have a lot of impurities which don't dissolve, but I don't think that's the case), but I didn't want to add more water to make it all dissolve because DDNP is slightly water soluble and I didn't want to reduce the yields further. I figured it should still react slowly even if it isn't in solution.
The yield of picramic acid from TNP seems very good, I haven't worked it out yet but it'll be on my site when I do.
When you've made the DDNP, dissolve it in acetone and filter it to remove impurities. I think these are unreacted picramic acid, in which case they could be dissolved in NaOH solution, filtered, and ppted by adding H2SO4. They would then be pure enough to be recycled.
Another thing I have noticed is that when the reaction works, the solution (with picramic acid, H2SO4 and NaNO2) goes red or orange/brown, when it does not it is a lighter yellow/brown. I intend to do some more experimenting to see if I can figure out what's going on.
Actually, before I write it up, I think I'll make some picramic acid and then try Mega's procedure for converting it into DDNP, to see if it's any better. Or maybe I'll check the ratios of the KIBC method and see if anything doesn't seem right.

Edit: actually, you might want to try purifying the DDNP with an alcohol instead of acetone. I don't know how soluble it is in ethanol (or whatever you decide to use), but with acetone you might get condensation reactions between the carbonyl group and the -NH2 on the unreacted picramic acid, and it might then be harder to recycle.

Edit: something else I forgot to mention is that you should have good ventilation when acidifying the sodium picramate solution. H2S and SO2 will be released, from unreacted Na2S and Na2SO3 formed when making the Na2S.

<small>[ July 10, 2002, 09:36 AM: Message edited by: Mr Cool ]</small>

[kingspaz]

i am also about to carry out the diazon reaction mr cool. KIBC does not do it the way i would...infact the stuff you filter is sodium picramate which is then converted to picrric acid by the addition of H2SO4, the excess being added so the is acid present to convert KNO2 to HNO2.
the i would do it would be:
prepare a slight excess of Na2S using NaOH and a slight excess of S (so all NaOH used up). mix in solution and heat until its done reacting. pass through a filter to remove excess S. next add the correct amount of picric acid to this. since there is a slight excess Na2S all TNP is used up.
then to this add a solution of HNO2 prepared from dilute H2SO4 and KNO2. then add ice water after the reaction is complete and filter.
my method is much easier on chemicals and the brain but my question is why does KIBC do some rounderbout synth?

[Mr Cool]

I wouldn't call the KIBC method roundabout: make sodium picramate, purify it, convert to picramic acid, diazotise.
Your proposed method is essentially the same, except that you purify the picramic acid of unreacted S before you make it, if you see what I mean, and acidify the NaNO2 rather than the picramic acid solution.
And I'm afraid your plan has two (very minor) flaws compared to the KIBC method: 1) the reaction between NaOH and S probably won't react all the NaOH, so you will still have to acidify the picramic acid to make sure that there's no OH- to interfere with anything, and 2) HNO2 is unstable, so it'd be a bad idea to make this first rather than in situ, as it will slowly decompose. If you add all the HNO2 at once this won't be a problem, but if you do it drop by drop then it could be. Very minor flaws like I said, but the other method doesn't have them <img border="0" title="" alt="[Wink]" src="wink.gif" /> .
I think next time I do it I'll make the picramic acid and wash it, then use excess NaNO2 and a slight excess of HCl to convert all the NaNO2 into HNO2. I like your idea of working out the amount of acid needed, rather than just adding it 'til you think you've added enough!

[Microtek]

I've decided that the most probable cause of my failure is the impurity of my nitrite. Therefore, I am going to try using a method which does not need nitrite. One such method is to dissolve picramic acid in ethanol and bubble N2O through the solution. Picramic acid is easy to prepare and is sufficiently insoluble in water that little is lost during washing. N2O should be easy to prepare from AN.
Yield may not be overwhelming ( though I don't know for sure ), but at this point I'll be satisfied with any product at all.
This leads my to ask what your picramic acid looks like when obtained by acidifying the red sodium picramate soln. Is it yellow or red ( mine is yellow ) ? Does it dissolve in acetone and what is its solubility in this and in ethanol ?

PS: I've always preferred to react chemicals in solution if possible, to avoid unreacted chems in the center of solid particles. For this reason I have tried adding the KNO2 to the sodium picramate soln before acidifying. The result was the same as always: A brown/yellowish precipitate which was barely flammable, but which would give a weak puff if heated to deflagration on a piece of Al foil.

PPS: It just ocurred to me that it may not be N2O but rather NOx that needs to be bubbled through the alcoholic soln of picramic acid.

<small>[ July 11, 2002, 05:22 AM: Message edited by: Microtek ]</small>

[Mr Cool]

I was thinking about using the normal method, but with ethanol as the solvent during the diazotisation... I'll try this next time, I made some more TNP last night so I'll try it today or tomorrow.
My picramic acid could be called "yellow", but it isn't a nice yellow. Nothing like this <img border="0" title="" alt="[Wink]" src="wink.gif" /> , for example. "Dirty" might be a better word to describe it's colour! It's certainly not red, it's more yellow than anything else.
I'm afraid I didn't do any experiments on its solubility, this is another thing I will do next time. Although I'm not sure if I have any acetone left...
I think you would need to bubble through a mixture of NO and NO2, equal molar amounts of each, to convert the picramic acid:
2 (-OH) + 2 (-NH2) + NO + NO2 --&gt; 2(-O-N=N-) + 3 H2O
This gas mixture could be obtained with your impure nitrite by warming it with acid:
2 XNO2 + 2 HY -warm-&gt; 2 XY + H2O + NO + NO2

[kingspaz]

i tired the DDNP synth i suggested and it appeared to work ok until i added the KNO2. the mix then turned yellow and after all the KNO2 had dissolved i was left with a liquid full of crystals. upon filtration they appeared a grey/brown colour. i then tried to dissolve them in boiling acetone which didn't work too well as i ended up with a red solution with lumps at the bottom...i'll test some of the lumps i collected once they dry for sensitivity.

[Mr Cool]

Kingspaz: any DDNP will be in the acetone solution, I think the lumps are mainly picramic acid.

[kingspaz]

shit!
i also forgot to mention when i dumped the acetone solutino into ice water the solutino turned yellow and nothin crystalised. sorry i fogot to say that.

[Microtek]

Kingspaz: That's almost exactly what happens when I do it. The brownish lumps that are insoluble in acetone are flammable, but definitely not a primary explosive and the acetone solution is reddish as you say. When this solution is dumped into cold water, the liquid becomes a foggy yellow and it seems that there is a lot of precipitate floating around, but it never ( after a week ) collects at the bottom and is too fine for filtering off, even with good filter paper.

[kingspaz]

thats good then. well its bad but good. its bad that it happens. infact its fuckin gay that it happens but its good that i'm not the only one, which shows at least the method i used was ok.
microtek, can you post the ratios you used and state where you aquire them. i think i may know what the problem is.
right i used:
180g H2SO4 (approximately 30% from car battery, excess should have used 120g and still would have been excess)
20g KNO2 (impure prepared from Al powder and KNO3, calculated to need about 5g if i remember correctly)
?g TNP (prepared from ASA from aspirins) i can't remmebr how much TNP i used. i think i used 15g actually
errr
5g NaOH
5g S (excess)
i used the procedure i stated in a post above somewhere.

<small>[ July 16, 2002, 05:39 PM: Message edited by: kingspaz ]</small>

[Microtek]

I used 3 g TNP from aspirin, re-crystallized from water to remove lesser nitrated phenols. I think I used 0.5 g NaOH to react with the TNP and 2.5 g NaOH plus 2.5 g sulfur for the sodium sulfide.
The NaOH and the sulfur where commercial products.
I then used a number of different procedures for the diazotization step, using either Na3(CoNO2)6 ( lab grade ) or homemade KNO2 from lead + KNO3 recrystallized several times from water. The acid were either HCl or dilute H2SO4, both commercial and quite pure.

[Mr Cool]

I also remember getting a red acetone solution with lumps, but I can't remember whether that was a time that worked or a time that failed :( I know I always get lumps, but I can't remember what colour the solution was.
But DON'T dump it into water, boil the acetone off over a water bath instead. I was surprised by DDNP's solubility in water.

[kingspaz]

shit...i've probably got a DDNP solution in the conservitory! i'll have another go at the weekend if i have time using the picramic acid (lumps) from the last attempt. no actually i won't. i'll make a shit load of KNO2 and purify it instead of using the raw shit i used last time. thanks for the help guys! if my procedure works then i'll write it up properly for you microtek as it uses less chemicals.

[Mr Cool]

If you can be bothered, it might be worth using H2S instead of Na2S (just add a sulphide to an acid, and bubble the gas through your TNP soln.) and NO and NO2 instead of KNO2 and HCl/H2SO4. Add your impure nitrite to an acid, warm it, and pass the gases through the picramic acid solution (in ethanol?). This will keep everything nice and pure, and it means that you won't have to waste any KNO2 in purification.

Both gases should be added slowly, with good stirring, and in a tall, narrow container to ensure maximum efficiency.

[kingspaz]

haha, i think for me it would be less hassle to lose some KNO2 in purification. but it think next time i carry out the reduction of TNP i will add the solution to water to precipitate the picramic acid. then i will use that in a H2SO4 solution and add the hopefully purer KNO2.

edit: it'll probably be somtime next weekend i do this because i have alot to do this weekend and the beginning of next week.

<small>[ July 19, 2002, 03:49 PM: Message edited by: kingspaz ]</small>

[da man]

Mr Cool, i've tried the exact procedure you said twice now and both times it didn't work! The first part of getting picramic acid works well. However on the second step, i put the picramic acid in water(which just stays under water, and doesn't dissolve) , add sulphuric acid, cool the solution to below 5*C, and then slowly add my saturated solution of sodium nitrite (bought from a lab NOT homemade). As i add the sodium nitrite, the solution fizzes a bit (decomposed nitrite). I then leave it over night, and in the morning, the picramic acid is still sitting on the bottom unchanged!! :mad:
Why doesn't it work? What am i doing wrong? Also what changes do you see happen to the picramic acid, when it is diazotised?

[da man]

This is so wierd! I just filtered off (from the sodium nitrite/sulphuric acid mix) what i thought was still unreacted picramic acid. I then boiled 200ml of water, and dissolved 10g of NaOH in it, and dumped the picramic acid in it. The solution went a very dark red as expected but there was a yellow/brown precipitate on the bottom of the solution. I added more NaOH, but it didn't dissolve or change. Then my bloody thermometer broke, spilling mercury into the solution, which got mixed into the precipitate at the bottom. And after a while of sitting, there is a very small amount of black precipitate at the bottom (probably mercury picramate :D hehe, could be interesting). Anyway i filtered off the yellow/brown precipitate at the bottom, took a sample, and tried to dissolve it in acetone. The yellow/brown stuff didn't dissolve, but the acetone turned BLUE!!! like it had copper sulfate dissolved in it or something!!! Maybe this is the mercury picramate (or whatever that black shit is), i don't know, but i guess the yellow/brown precipitate couldn't be DDNP if it doesn't dissolve in acetone :( Oh well, i guess i will try reacting the sodium picramate solution with sodium nitite, and HCl now.
This is getting so frustrating, nothing works!! Can anyone help me as to what im doing wrong and what the hell is going on?!

Thankyou

Edit: Ok, this yellow/brown precipitate is not:
1) Picramic acid (doesn't react with sodium hydroxide)
2) DDNP (does not dissolve in acetone, does not burn quickly, just smoulders and leaves behind a peice of carbon)
3) picric acid (insoluable in water, doesn't react with sodium hydroxide)
4) Anything else i can think of!!

I've done this reaction another couple of times, and each time i get a mixture of picramic acid, and this yellow shit!! I'm really getting pissed off! Could it be some impurity from when i was making picramic acid??

<small>[ August 04, 2002, 04:31 AM: Message edited by: da man ]</small>

[kingspaz]

the problem is to get the picramic acid to dissolve. what i'm hoping to try is dissolving the picramic acid into hot H2SO4 (98%) then adding this slowly to a KNO2 solution with vigourous stiring. that way the picramic will not precipitate out...hopefully...
the yellow precipitate is picramic acid also i believe. after i made some picramic acid with Na2Sx and TNP i ended up with a brilliant yellow precpitate which looked kinda globular.

[da man]

Kingspaz, if you use very concentrated acid like that and add a solution of KNO2, i'm afraid that the KNO2 will decompose instantly into NOx. Even with 30% HCl it decomposes instantly into NOx!!
Possibly there is some other solvent that could be used though.
And the yellow/brown precipitate i keep getting is not picramic acid, because even with numerous attempts, it will not dissolve in hot sodium hydroxide solution!

[kingspaz]

da man, you misunderstood what i said. i said i will dissolve the picramic acid in hot H2SO4 then add this a little at a time to a KNO2 solution. if i stir it alot then the acid will mix with the solution and be diluted. how did it go when you tired picramic, NaNO2 and HCl?

[Mr Cool]

Even with that method, you will still get an awful lot of KNO2 being wasted.
An idea I have been thinking of is to dissolve the picramic acid in methylene dichloride, adding it to an aqueous solution of a nitrite (thus forming two layers), stirring it very rapidly and dripping in the acid. This will be a slower reaction, since the HNO2 will have to diffuse into the MeCl2, but I think that picramic acid should be quite soluble in MeCl2, so you will get a much more complete reaction. Maybe.

Da man: I don't know what is wrong. It fails very often for me too, I don't know why :(
I think the main problem is the low solubility of picramic acid in water, I think the MeCl2 method might solve this. Next time I'm in a mood for experimentation I might try it, but it won't be very soon since I use Pb(N3)2 as a primary.

Edit: stupid error.

<small>[ August 05, 2002, 04:06 PM: Message edited by: Mr Cool ]</small>

[da man]

The military use this primary don't they? Is it used at all in industry? It would be interesting to know how they perform the reaction? Does anyone have any information on how they do it?

[Al Koholic]

OK....it seems to me that both this and the archived file on DDNP are pretty inconclusive. I have just spent the last 8 hours messing around with the procedure just for making picramic acid. FIrst of all, I know that a good deal of my trouble comes from there not being a good proceudre out there. I found recipies and all but none of them say for example "the x should now appear so and so..." or "there should now be a precipitate" or something along those lines. For me, since I didnt know what it SHOULD be doing it got kind of creative along the way and I believe that right now I mayyyyyy just have some picramic acid filtering out as we speak but that will remain to be seen. Bottom line is this:

1) Should one filter the Na2S solution if there is some undissolved residue in the bottom at the end of the reaction?
2) When making the TNP/NaOH solution, should one make sure that ALL the TNP has dissolved? When I just did it, it did not all dissolve in the amount of water I used.
3) When adding them together, I added the TNP/NaOH solution to the Na2S solution in small batches. The first addition the whole thing turned greenish grey (from one red/black Na2S solution and one bright orange TNP/NaOH solution). Then upon subsequent additions it turned progressively more red/brown. Should this happen? There was an awful lot of what looked like unreacted TNP at the end in the bottom of the beaker.

Here are the chems and amts I used:
-to 200ml of H20 I added 20 grams of NaOH and 20g of powdered S. Heated it and got the Na2S solution. There was a little insoluble residue in the bottom from impurities in the S but I didnt worry about it.
-to 180ml of H2O, I added 20g TNP and 3g NaOH. This was bright orange in color and not all the TNP dissolved.

When adding I experienced the noted color changes but also at the second to last addition, the resulting solution was getting to the consistency of paste, then at the last addition it turned back to liquid and got increasingly liquid upon standing. I let it stand for 30 min with stirring every 5 min. Then filtered it. I have a lot of yellow precipitate in the filter paper and a beaker of dark fluid. I added the yellow precip to water to store and mess with later. The dark filtrate I thought might be sodium picramate so I added 93% H2SO4. This caused black/brown precipitate to fall out. With increasing addition of H2SO4, some of the brown precip disappeared and the black was left and these were HUGE crystals. Soooo, I added more of the original filtrate to counteract what I thought was too much acid added. THe brown crystals returned to coexist with the bigass black ones. Unfortunately I did not document how much acid I was adding, this was kinda just messing with it. Anyway, I was able to test some of the black crystal and it does not dissolve in water to any appreciable extent....still waiting on the main precip though. Lemme know what you guys think and maybe....just maybe....we can keep this going till we reach a concensus on what exactly needs to happen b/c as far as I am concerned the net just does not contain too much accurate info on picramic acid synth. ANyway, just a suggestion.

Al

[kingspaz]

Al, try using less water for the TNP/NaOH reaction and try using a little more NaOH. you could work this out yourself you know. basically if you acidified the solution that you made from Na-picrate and Na2Sx and got a precipitate then it is picramic acid. i think the acid you used was waaaaay to higher concentration. you should have first diluted it down to around 30% and used that instead.
also DDNP synth is a bitch so 'messing around' is only going to waste chemicals and could be your downfall if you mess the wrong way and it blows up in your face. picramic acid is also explosive :rolleyes:

[stanfield]

picramic acid isn't very sensitive ! I never got an accident with it ! don't worry...

[kingspaz]

stanfield, i'm not worried and i know its not very sensitive. i was just pointing out to him that if he keeps messing round sooner or later something will blow up in his face. sensitive or not all explosives should be handled with care and treated with respect.

[Al Koholic]

Thanks for the advice kingspaz...the messing around is kind of how i get a feel for what i'll be doing in the future...breaking ground...proof of concept kind of thing. Anyway I don't have a shortage of chemicals around at all so the loss is not an issue, plus I only do small quantities.

Anyway getting back to the point here, since the messing around stage is over, I have been working on getting this synth to work now in a much more exact way and have come to a few conclusions: either I am blatantly missing something, Im not using pure enough chemicals, and I am going to scour my university library when I get back from xmas break for a good synth. I have some interesting stuff on making picramic acid itself which I'll scan and upload to the ftp. The article explains how adding NaHCO3 to the Na2S solution will increase the yeild because of the higher prevalance of NaHS and how using a 60% methanol solution instead of plain water in the TNP/NaOH step increases yeild to like 97%.

Just now I:
Made a Na2S solution with 7.5 grams of NaOH and S.
Made a sodium picrate solution with 1.5 g NaOH and 9 g TNP. I believe I should probably use a tad bit more NaOH.
When I mix these two however I obtain a water insoluble off white precipitate and the liquid turns blood red. The red solution is an indication to me that picramic acid is forming but the off white precip is stumping me. I do not obtain red crystals contrary to the common recipe going around. I wonder if anyone has ever gotten this precip as well? Anyway...from there on I add the precip to boiling water and filter hot and end up with a red solution (this is most likely from the residue on the powder). To the red solution I add by drop H2S04 (93%) till it changes to yellow (supposed to be brown) and then I add 7 grams more acid. This is mixed with 5.4 grams NaN02 in 240ml H2O and I end up with a yellow solution which bubbles like a soda fizzing (only NO2 comes off instead of CO2 hehe). However NO DDNP.

I believe this is my next step...
Purify the sulfur I use. It is 90% powdered sulfur...10% inert ingredients, used for gardening. Im going to dissolve the S in EtOH, filter, and evap EtOH into a condenser for re-use. The problem I am having is that not all of the sulfur is reacting in the boiling mix so I think either impurities are getting in the way OR I am not using correct amounts of each substance (however I am following the synth). I will try some experiments tomorrow to determine how much NaOH I need to use to fully react the sulfur.

Anyone have a suggestion?
Al

[kingspaz]

the white precipitate is picramic acid. the red solution is picramic acid which has reacted with excess NaOH to form sodium picramate. the red crystals which are supposed to be formed are sodium picramate which then gets converted back into picramic acid upon addition of the H2SO4. the problem with the sodium picramate is that it is an absolute bitch to crystalise!!!
i ended up with a super saturated solution some how during one of my attempts. it just wouldn't crystalise then i thought i'd just pour it through the filter and hope for the best then it just fell out of solution instantly. weird...

[Microtek]

Sodium picramate is very soluble in water, though I forget the exact numbers. Picramic acid is very insoluble ( less than a gram per liter at 20 C I think ).
The reaction of NaOH with S also produces Na2S2O3 :

6 NaOH + 4 S --> 2 Na2S + Na2S2O3 + 3 H2O

When this solution is reacted with HCl large amounts of a yellow precipitate which I think must be free sulfur is formed ( along with lots of H2S of course ).
If H2S is bubbled through NaOH soln, NaHS is formed which is at least as desirable for partial nitro reduction as Na2S. You could also mix the soln from the reaction of NaOH and S with a soln of a Zn(II) salt to precipitate ZnS first, then isolate this and react it with H2SO4 to produce H2S. H2S could be used to make NaHS as mentioned or it could be used directly by bubbling through a soln of picric acid or Na-picramate.
BTW, I did some research on the subject of partial reduction of polynitro aromatics and found that the reaction is not as fast as the recipes for DDNP imply; the reaction is preferably done at 70-80 C and takes 30-45 minutes. Another point was that pH of the reaction should preferably be kept between 7.5 and 9.0 .

[Al Koholic]

Kingspaz, that is quite interesting about your attempt. How much sodium picramate precipitated and was it mixed with picramic acid as well?

Microtek, where have you been conducting this research? I have scoured all the sources I can think of on the web and all I can come up with is that regular procedure (I think you know the one I speak of), which is quite inadequate.

I was thinking that if I'm getting a bunch of picramic acid as precipitate, then could I not just add some amount of NaOH solution (most likely quite concnetrated) to convert the free acid into the sodium salt before I filter the solution which results from the mixing of the Na2S and NaOH/TNP solutions? If this would not work wouldn't it also be possible to keep the filtered picramic acid and add it to a new solution of NaOH?

Al

[kingspaz]

i think the only reason it is filtered in most 'recipies' is to purify it. the problem seems to be getting picramic acid to be soluble. i can't see it reacting properly if it insoluble. well, i think that is part of the problem.

[Al Koholic]

Kingspaz, looking at merck just now I read that picramic acid is a red crystaline substance. This is prepared from the ammonium salt in this case but that shouldn't matter. What then could the white stuff be?

[Microtek]

Picramic acid is red if it is crystallised from alcohol but it is yellow in acidic medium.

[Al Koholic]

Alrighty, I just made another attempt at DDNP. Well, more accurately, I am in the middle of it.

I have come up with a fairly decent method of making a good amount of picramic acid (I have not weighed my yeild yet...still filtering).

1) Heat to boiling or almost boiling; 7.5g of Sulfur and 7.5g NaOH in 250 ml of H20 for 20 minutes, or until the reaction looks complete.

2) Turn off heat source. Add 4 grams of NaHCO3 to 50 ml of H2O. Slowly add this solution with stirring to the Na2S solution and allow to cool to room temperature. Upon addition, the Na2S solution will turn from dark red to a bright orange. Filter this solution and discard the crystals/powder collected.

3) Add this solution slowly to a solution of Sodium Picrate prepared from 9g TNP and 1.5g NaOH. I used about 275 ml of H2O to get all the Sodium Picrate to dissolve. There was only a small amount of residual powder that did not dissolve. The temperature of the added water was 60 C and this was maintained on a water bath.

4) Maintaining the 60 C temp, add the reducing solution which was prepared before to the Sodium Picrate solution slowly over the course of 15 minutes with constant stirring. Once it is all added, allow the mixture to sit on the heat source for an additional 25 minutes.

5) Allow this solution to cool to room temperature and filter it. There will be a small amount of off white crystals collected in the filter paper (I assume a small amount of picramic acid...). Wash the filter paper with hot water and discard the off white crystals.

6) To the resultant, dark red solution, add enough 15% HCL to cause crystallization of the picramic acid as a red precipitate. Continue adding the dilute acid with constant stirring until it is visible that no more picramic acid is crystalizing. Sorry I did not get a quantitative measurement on the volume of acid I added. The color of the liquid phase of the mixture will now be a light milky brown.

7) Filter the crystals out. (This is where I am now).

This part seems very easy. I did the same thing last night and then followed the rest of the KIBC recipe and I got some crystals but not very much and when I attempted to wash them with a small amt of water they dissolved....is DDNP very wate soluble?! I didn't think it was...

edit:

BTW Microtek, after reading the first post I remembered to add this:

I use TNP prepared from pure ASA, recrysalized from denatured alcohol. The NaOH I use came from "Draino Crystal" drain cleaner. It is also quite pure as I recrystalize it from distilled water. The sulfur is unfortunately only 90% pure (used for gardening). The other 10% I believe is inert filler. Im working on getting a way to purify this too...most likely with acetone the same way I do with ASA.

<small>[ February 11, 2003, 02:47 PM: Message edited by: Al Koholic ]</small>

[Mr Cool]

OK, I've had a little think, and might possibly have found a very obvious reason why it keeps failing. Maybe.

DDNP is not the same thing as diazotised picramic acid. Diazotised picramic acid is ionic, and you basically need to remove HCl (if that's what acid you used in the diazotisation reaction) to form the bicyclic DDNP molecule from the diazonium ion.
Every method I've seen attempts to produce DDNP in a strongly acidic medium, because diazotisation requires acid. Therefore, the equilibrium

DDNP + HCl <==> diazotised picramic acid

will be far to the right, because the DDNP is protonated. This makes it ionic, and therefore more soluble in water. In order to ppte it, maybe it needs to be deprotonated?

What I propose is this: next time anyone tries to make DDNP, assuming they fail, try basifying your reaction mixture with a load of NaOH.
It's worth a try.

Comments?

[stanfield]

I don't make DDNP anymore since I have sodium azide but, I uploaded a file on the forum ftp, in the "-=upload=-" directory, named "Method for producing diazodinitrophenol - upped by Stanfield.rar". It'a an interesting patent I've found.

It says : " </font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica"> Where the acid is added gradually for the production of DDNP in a free-flowing form, the addition will be at a relatively slow rate, say, for example, at a rate of about 0,001 grams HCl per minute per gram of sodium picramate, [...] </font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">The rate of addition is really low, maybe it's required to sucess the synthesis ?

[Al Koholic]

Thats another one of those variables I am just not sure about. Some people and sources claim the addition has to be very slow. Some say dump all at once with rapid stirring....

I'm not attempting any more DDNP until I have made pure Na2S to use in my solution.

Mr Cool...
When you say "diazotised picramic acid" are you thinking of like N2+ and O- on the ring? If so I could see that happening...the charges being stabilized by the Cl- and H+ respectively...

The last attempt I made (3 posts up) ended up in pretty bad shape. I did manage to precipitate what I believe is picramic acid but not a lot. I got like 2 grams tops. It is a redish/brown crystal. I dissolved it in alcohol, then filtered and separated out a lot of insoluble black powder. I evaporated the alcohol and got red/brown crystals I have now. I have a paper with a bunch of research into reducing TNP to Picramic....they got 96% yield with one of the reducing solutions. I clearly have a lot of preparation to do before I get anything like that.

[andreas]

As far as I know DDNP is broken down in a cold KOH or NaOH soln.
I may be wrong. But I bought me some asprin so I will be doing some new experiments in a few days.

[Mr Cool]

OK, maybe making the solution basic is a bad idea. But I still think getting rid of some of the acid is a good idea.
<a href="http://www.boomspeed.com/mrcool/DDNP-Theory.jpg" target="_blank">This</a> should help to illustrate what I'm thinking.

I have nothing to support this, it's just an idea.

[Al Koholic]

That looks like a good diagram to me in theory. I can't really offer anything of use on the subject. It may behave that way and IMHO it should but you never know.

[andreas]

I've got the feeling I'm missing something here, altough I can't put my finger on it. difficult to explain!
But I must say when I look at it it seems right.
Maybe in a neutral soln?
But if you want to get as much acid out as possible you need to know if ddnp causes a basic or an acidic soln. with the little bit that does dissolve. If my post doesn't make sence I'm a little drunk at the moment.
I've made some TNP yesterday so I will try a new batch of ddnp sson I hope.
First I want to get some pure sulpher as I always use the garden stuf of wich I purified the brown stuff out of.

<small>[ February 16, 2003, 12:02 PM: Message edited by: andreas ]</small>

[Al Koholic]

Well Ill tell you what...Ive been drinking pretty hardcore for the last 3 hours and before that I was drinking (at bowling league) pretty regularly for 3 hours as well. Fridays tend to be this way for me even though Im taking the MCAT in like 3 months. Anyway, the only application I can apply to this structure would be that of an amino acid... I begin to wonder what the pI of DDNP would be....

Disregard this post...it may be completely useless as was my last one.....I appologize for this lack of informative content. I'll have MUCH more real info in a few week probably.

Peace
Al

[andreas]

Whell I've had another try today and it failed misserably again.
When I added the "believed to be sodiumsulfide soln" to the sodiumpicrate soln. I didn't even get a precipitate.
Whell then I acidified it thinking that I had sodium picramate and it turned yellow and I got a precipitate. This however smells like SO2 when burned and is a light precipitate. When I tried to diazotisize it, it didn't do anything.
Any thoughts on this.
I used the kibe method.
And used agricultural sulpher wich in holland is called (spuitzwavel)
wich is translated freely (hosingsulpher) it is used as a fungicide

[Al Koholic]

I've gotten that light flakey precipitate before as well. In fact, I've gotten it almost every time I do this reaction and now I have to purify the supossed picramic by dissolving it in ethanol and filtering out that stuff.

I believe that the material is what is referred to in a journal article on reduction of TNP as "sulfide dyes". I am not entirely certain what this is supposed to mean in terms of chemical structure but apparently they are a significant by-product of this reduction reaction, ESPECIALLY when utilizing non-optimal solutions and reagents(which the KIBC method is full of).

How much acid did you add to the solution and what was its concentration? For the regular KIBC method, I was adding between 20 and 30 ml of concentrated (31.4%) HCl to the solution. This was most likely too much but it takes quite a bit to precipitate ALL of the picramic acid. BTW, when you mixed the two solutions did the solution change color at all? It should have ended up blood red if you got any reduction at all...

Al

[andreas]

Never herd of it. But I added about 30ml of 50% H2SO4. When I added the reducting solution it turned blood red indeed. But the precip I got after the acid was more like sulpher.

[Polverone]

I managed to track down a non-fringe-literature source for the preparation of picramic acid, from a book on dye chemistry. The instructions given are more detailed than those found in KIBC and the like, and hopefully will give good results.

<a href="http://www.sciencemadness.org/library/picramic.pdf" target="_blank">http://www.sciencemadness.org/library/picramic.pdf</a>

[Al Koholic]

Polverone, I have some good articles from various chemical journals regarding picramic acid and DDNP. I have photocopied them from the journals and have them now. I also have a scanner but I do not know how to turn them into .pdf format. Once I research it and figure it out I'll upload them to the FTP, or I can email them to you. I don't know how to post it on the web like you did with that link.

[Polverone]

If you give me scans I can perform OCR, convert them to PDF, and host them. Check your e-mail.

[kingspaz]

does anybody know why reduction is prefered on 2 and 6 as opposed to 4? or is it at all?

[Al Koholic]

I'm pretty sure it has something to do with the resonance distribution of electrons in the ring and how it affects the ring substituents.

The oxygens on the nitro groups should have a partial negative charge and the nitrogen, a positive 1 charge. This makes the O slightly nucleophilic. Then you have the OH group. This could lose its H and become a negative 1 oxygen as well. But more importantly I believe is the ability of the non-bonding electrons of the oxygen in the OH group to make donate electrons to the ring. This is why OH is an activating group if I'm not mistaken. Nitro groups have a tendency to withdraw electrons from the ring and hence, deactivate it.

Anyway, drawing out the structure of TNP shows me that if one of the non-bonding pairs of electrons in the OH oxygen were to form a transient bond with the carbon it is attached to resulting in a double bond, you will end up with a positively charged oxygen and the rings electron configuration will shift. The double bond between C1 and C2, or C1 and C6 (they're the same) will move up to the nitrogen and force the oxygens on the nitro group to become more negative resulting in a net -2 charge (-1 for each oxygen). This must be the reason for the preferential reduction of the 2 position.

What I can't figure out off the top of my head here (I'm at work) is what would happen after this in the reducing solution. The oxygen is going to be HIGHLY nucleophilic at this point and is just jumpin to oxidize something...

The reducing solution in this case is Na2S in H2O. This mechanism doesn't seem to leave much room for intermediate structures and is most likely just involving a transition state. A single step here makes me think that NaHS or some other hydrogen containing reducer would be the main reducing agent. I don't know how this would work here...anyone else care to take it from here? I'll keep thinkin about this as it is one of my ultimate goals to learn every nook and cranny of every reaction I ever accomplish.

Edit: I'm guessing that the formation of hydrogen containing reducing agents depends on an equillibrium reaction between water and the Na2S. This is demonstrated in part by using NaHCO3 in the reducing solution to increase the amount of NaHS in the solution, and getting correspondingly higher yields...I can't remember the equillibrium right now.

<small>[ February 18, 2003, 01:19 PM: Message edited by: Al Koholic ]</small>

[kingspaz]

Al Koholic, thanks for the help! that seems to be a very credible explaination (but the i would say that because i don't know that much about chemistry yet :) )

[Al Koholic]

Hey no problem man! It's all about electron pushing my friend....

If you liked that explaination (which wasn't entirely complete as there are also inductive effects taking place) I can scan a few pages from my organic chem book for you if you want. They are very helpful pages for thinking about things like this. If you want 'em, I can e-mail em! :-)

Al

[Boob Raider]

Son of a Bitch....... I tried reducing Na-Picrate the 6th time and all I get is a reddish orangish brown solution. As soon as I add HCl or H2SO4 to it ..... it turns into what looks like a suspension of Sulfur. This material seems to be lighter than dil. H2SO4 (50%) as a band is formed when the red/brown soln is acidified slowly. This can't be just Sulfur as the amount of ppt I get is way more than the amount of S used to make the Na2S. Also the color of the ppt does not revert back to red/brown no matter how much base I add. Here are my observations ... I was going to conclude that maybe the 4 or 6 nitro is being reduced instead of the 2, but it should revert back to red brown on the addition of NaOH.

[will]

Son of a Bitch....... I tried reducing Na-Picrate the 6th time and all I get is a reddish orangish brown solution. As soon as I add HCl or H2SO4 to it ..... it turns into what looks like a suspension of Sulfur. This material seems to be lighter than dil. H2SO4 (50%) as a band is formed when the red/brown soln is acidified slowly. This can't be just Sulfur as the amount of ppt I get is way more than the amount of S used to make the Na2S. Also the color of the ppt does not revert back to red/brown no matter how much base I add. Here are my observations ... I was going to conclude that maybe the 4 or 6 nitro is being reduced instead of the 2, but it should revert back to red brown on the addition of NaOH.
I to have had troble trying to make DDNP i folowed a method that was downloaded for wantsomfets kangroo corner called Improvised primary explosive i filliter a redde brown solid that when it came in contacte with flame i smoldered with green smoke and did not show any propities of a primary explosive

----------------------

At first I thought warning you would suffice but obviously all help comes too late. Banned.

Rhadon

[K9]

I've just finished the addition of KNO2 to the solution of picramic acid and H2SO4. It fizzed and bubbled lightly which I assume is the reaction happening. My question is, how long do I leave it for before I filter. I've seen numbers from 10 minutes to 24 hours. It still fizzes very lightly when I stir it, but it's only been 15 minutes since the addition. What would be the best amount of time to leave it?

EDIT:

Well the solution was completely clear in an hour, and the precipitate settled to the bottom so I filtered it.

[BLASTER]

Finally I made successful synthesis of usable free-flowing form of dinol from picric acid via sodium picramate. Below are some pictures. In case of general interest, I translate (I'll try ;-) ) this method and release to public. It's based on preparation originally developed by D. Smolenski a J. Plucinski and also published in Urbanki book vol.3.

This is unusable amorphous form of dinol, resulting from inadequate reaction temperature and speed of HCl addition. It has gravimetric density only 0.27g/cm3
http://www.pyroforum.org/forum/files/dinol_amorfni.jpg

Amorphous powder (300mg) handpressed into aluminium cap to density 0.65 and ignited with bickford fuse on 0.7mm Al sheet
http://www.pyroforum.org/forum/files/dinol_300mg_dutinka1.jpg

This is finally right form of dinol (almost unbelievable difference). Gravimetric density 0.63g/cm3 (should be possible to reach 0.82 according to literature). Its really nice and easily pouring into cap ;-)
http://www.pyroforum.org/forum/files/dinol_sypny.jpg

And 300mg of this form easily handpressed into aluminium cap to density 0.92g/cm3 laid on Al sheet gives really better result :p
http://www.pyroforum.org/forum/files/dinol_300mg_dutinka2.jpg

And little of amorphous form put into flame create nice puff
http://www.pyroforum.org/forum/files/zazeh_dinolu.jpg

So I must say dinol is very promising for me, now easily prepared from sodium picramate. It has some very valuable properties for amateur.

[Bert]

if case of general interest, I translate (try ;-) ) this method and release to public. It's based on preparation originally developed by D. Smolenski a J. Plucinski and also published in Urbanki book vol.3

Is a bear catholic? Does the pope shit in the woods?! Yes, please do!

[Bert]

Not meaning to post whore or bug you, Blaster... But please? please? pretty, pretty please??? I suspect from the disparaging comments on DDNP from some that they've not achieved the granular, denser form. I'd certainly like to see the process fully described!

[K9]

The first pic is the stuff I got. So what needs to be done in regards to the temperature? Just keep it lower?
And I too would be extremely interested in the procedure. So please post it :)

[Bert]

Time once again for my weekly request for a full synthesis description from Blaster! Would it help if I started offering first borns, pounds of flesh & etc.?

[Rosco Bodine]

Relevant excerpt from Urbanski 3 , page 203 :

The effect of conditions of preparation have been thoroughly examined by Smolenski
and Plucinski . They found that at a diazotization temperature as recommended by
Clark , i.e. 15 C , the product pours with difficulty . Conversely , diazotization at a
higher temperature ( 25 - 45 C ) results in formation of a product with a density of
about 0.82 .

Smolenski and Plucinski , during a break from their usual work of turning the ladder
for Pollockski the overhead light bulb changer , prepared dinitrodiazophenol in the
form of free flowing crystals by applying the following reaction conditions :

A solution of 320 g of sodium nitrite in 2 l. of water is added to a suspension of
1000 g of the sodium salt of picramic acid in 8 l. of water . Next , 6 l. of 5.5% HCl
is added dropwise for 2 hr. , stirring continuously . The initial temperature of 20 C
rises to 25 C . Completion of the reaction is determined by means of starch-iodide
paper . The product is filtered off , washed with cold water and dried at 35 - 40 C .
Its yield amounts to 80 % of the theoretical .

[Bert]

Thanks! That's a good start...

[K9]

Well I'll have to try this way out next time. Sadly that probably won't happen till the summer, but thank you for the post.

[BLASTER]

Here are, proven and little corrected laboratory preparations of picramate and dinol. I apologise for my primitive expressions, but english language isn't my cup of tea ;)


Preparation of sodium picramate from picric acid

Reagens used in summary:
103g picric acid
825ml distilled H2O
180g Na2S.9H2O
7,5g of 35% solution of NaOH

- In 2l beaker containing 450ml of distilled water dissolve 7.5g of picric acid and add 7.5g of 35% NaOH solution. Put beaker into wider low profile jar for later cold water addition.

- Warm up solution to 45-50°C and while stirring intensively add gradually sodium sulfide (nonahydrate) solution containing 30g of crystalline Na2S.9H2O in 75ml of water. It's good idea to use warm water when dissolwing sulfide, because dissolving it in water cause significant temperaure drop and sulfide then won't easily dissolve.

- Afterwards while stirring intensively add into solution 95.5g of picric acid in small portions, together with evenly added (dropwise, use dropping funnel) second solution of sodium sulfide containing 150g Na2S.9H2O in 300ml H2O. Intensive stirring is necessary, because suspension of fine crystals quickly settle at the bottom of beaker.

- Addition of sodium sulfide and picric acid must end up in the same time.
Temperature of reaction mixture rise in time of reagents addition and must not rise over 65°C. Temperature is held on required level externally with cold water. Usually when about one half of reagents is added, 0.5l of cold water poured into wide jar is enough to held temperature for rest of reaction time (held temperature at 55°C all the time).

- When reagens addition is finished, held reaction mixture for next 10 minutes. Then filter out crystalline sodium picramate, wash on filter with 75ml of 10% NaCl solution and finally 20ml of cold water. After drying you should have about 80g (80% of theorethical yield) of finely crystalline sodium picramate with dark brownish-red colour. Beware of whirl picramate dust, it's very intensive colouring agent.

sodium picramate
http://www.pyroforum.org/forum/files/pikramat.jpg


Preparation of dinitrodiazophenol from sodium picramate

Reagens used in summary:
25g sodium picramate
250ml of distilled H2O
8g NaNO2 (sodium nitrite)
150ml of 5.5% HCl

- Into 600ml beaker containing 200ml of distilled water add 25g of sodium picramate. Stirr intensively to mix it into homogenous suspension. Put reaction beaker into wider low profile jar.

- Then add while stirring solution of 8g sodium nitrite in 50ml of water.

- Afterwards 150ml of 5.5% hydrochloric acid solution is added dropwise (1 drop every 4 seconds) while continuously stirring. Addition of HCl solution must took 2 hours, while temperature of the solution must be held constantly at 25-30°C by addition of hot water into wide jar (or little of cold water if temperature rising too much). Reaction heat itself isn't capable to held temperature at desired level.

- After whole volume of acid solution is added, reaction mixture must have pH of 3 (blue congo red paper) and turn blue iodide-starch paper, because of free HNO2 excess (in case we haven't iodide-starch paper, we can smell it over beaker)

- Then after decantation and filtration, we can dry prepared dinol in warm dark place on filtration paper. After drying we should have about 20g of final product (84%).

Note: Dropping funnel is really necessary for HCl addition, which must be done continuosly and evenly for two hours, also with reaction temperature held on desired level and continuous stirring. These three conditions are necessary for obtaining high density free flowing product.

DDNP
http://www.pyroforum.org/forum/files/dinol_sypny.jpg


Ref.:
W. P. Cetner - Preparatyka materialow wybuchovych
T. Urbanski - chemistry and Technology of Explosives vol. 3

[K9]

Thank you! :) That is greatly appreciated. So it's really a huge matter of the addition time and temperature of the HCl. When I get to to do this next I'll make a detailed write-up of how it goes for me.

[Rosco Bodine]

Years ago I did some experimentation with DDNP but abandoned the
experiments primarily because of the difficulty of obtaining a useful density
of crystalline product directly from the diazotization reaction . Seeing now
that perhaps that difficulty has been solved is an interesting development .

While doing those old experiments , another aspect of the process for DDNP
concerning which I did a few experiments , was the synthesis of the
sodium picramate . While I never did perfect the synthesis to a point
where it was "optimized" , I did get what appeared to be good yields
by the following method :


Sodium Picramate from Picric Acid , Sodium Hydroxide , and Sulfur

A good quality of deep red crystalline sodium picramate in good yields is possible via
the sodium polysulfide reduction of sodium picrate . Several times I have repeated the
experiments and found that slight adjustments in reaction conditions can improve the results ,
so I have not yet determined what conditions are optimum . Please feel free to tweak the
general process , if you want to do the work . The polysulfide reduction is quite similar
to the synthesis described in your library . The problem that I have seen in the online
descriptions of the polysulfide reduction , is a lack of detail about the correct method
of preparation for the sodium polysulfide reagent . A thorough , intimate mixing of the
correct proportions of NaOH and sulfur , being first thoroughly mixed as DRY ingredients ,
which absorb moisture from the air very gradually , darken in color , and initiate a spontaneous
highly exothermic reaction while being stirred is the required approach for producing a good
polysulfide reagent . If atmospheric moisture is low , a trigger mister can be used to
get things going . The idea is to get the reaction going from a stirred dry powder which
becomes crumbly as it warms and darkens and then a drop or two of water is added , the mixture
stirred very well and a few more drops of water added , whereupon the reaction then proceeds
on its own to form the polysulfide very quickly as a dark red but transparent liquid which looks
bright yellow in thin layers . The stoichiometry for reactions involving polysulfides is not fully
known . The goal is to get a good reduction without a great precipitation of elemental sulfur
as a contaminant . My own theory is that if the alkalinity is just right , the higher polysulfide
which is decomposed in the reduction can be converted to a lower polysulfide and remain
in solution , instead of precipitating free sulfur . The polysulfide may possibly even reform
from its fragments after acting as an unstable intermediate compound in the reduction . I am
uncertain that the actual mechanism for the reaction involving polysulfide is even known ,
beyond the knowing that it just works somehow.

The following is from my *old* lab notes , with commentary ideas included .

Experimental :

On a hotplate stirrer is placed an 800ml beaker and with stirring , 22.9 grams , ( .1 mole ) picric acid
is dissolved in 400ml boiling water . Heating is stopped . To the stirred still hot solution is added
a solution of 4.2grams NaOH ( .105 moles ) in 25ml water .

comment : easy solution was noted so less water may be useful in subsequent syntheses .

While the slightly alkaline sodium picrate solution is cooling , a Sodium Polysulfide reagent
is prepared as follows :

NOTE : All of the following procedures should be done with good ventilation , toxic gas is produced .

Into a 100ml beaker is placed 13 grams NaOH fine prills and 10.1 grams powdered sulfur
( flowers of sulfur USP ) Using a glass stirring rod the granular materials were manually mixed dry
as thoroughly as posssible , and as the stirring was continued the mixture began to take up moisture
from the air and darken in color slightly , and the physical texture changed as the mixture became stiffer
and more difficult to stir . The particles become adherent to each other and the mixture begins to warm .
A couple of drops of water are fed from an eyedropper onto the stirring rod and stirred into the mixture ,
then two drops more , and stirring is assertively done between dropwise additions to blend the very gradually
increasing moisture into the reactants .The induction of a highly exothermic reaction occurs concurrently
with the slight dampening of the mixture which may need to be stirred yet a little more
if any "dry lumping" is observed . The pasty mixture gets really hot and darkens quite rapidly ,
with an evolution of intense "sulfur fumes" from the melting and reacting sulfur . Hold the beaker
by the upper rim where it is cool and do not get burned by touching the walls of the beaker near
the reaction mixture . The addition of water two or three drops only , in each addition may be continued
portionwise , with stirring between these small additions , in order to maintain the heat by reaction
and heat of dilution , until a dark red transparent solution results . The hot reaction mixture should
become a thin and mobile enough liquid that further mixing and dilution can be done by manually swirling
the beaker lightly .

Once the pasty mixture has cleared to a hot solution ( melt would probably be more accurate description ) ,
then gradual additions of water in increasing amounts should be made by the eyedropperfull until the volume
of the resulting solution is about 40ml volume . If a dark red melt clear of solids fails to form completely
on its own heat of reaction , at this point DO NOT add a lot more water and "boil" or a partly crystallized
failed to complete reaction mixture will probably result . If 1 or 2 ml of added water is insufficient to "kick"
the reaction by heat of dilution , then supplemental heat will be required to drive the reaction to completion ,
before further dilution to a volume of 40 ml . This dilution should be sufficient to prevent the reagent from
crystallizing upon cooling . Keep the polysulfide reagent from contact with the air after it is prepared .
Air may degrade and cause precipitation of elemental sulfur from the polysulfide reagent if it is left standing
uncovered . The prepared reagent is put into a separatory funnel and supported over the still warm
sodium picrate solution prepared earlier . A piece of plastic wrap is secured over the top of the beaker with
a rubber band and the plastic wrap is puntured in the center to admit the tip of the separatory funnel .
This is done to exclude air from circulating freely around the surface of the solution in the beaker during
the addition of the polysulfide solution . A seal is not needed here , a loose covering is sufficient . To the
stirred sodium picrate solution at 44 degrees centigrade , was added the sodium polysulfide at a rate of
one drop per second to one drop per two seconds , with stirring continued for one hour . The mixture
was then covered to the complete exclusion of air , and allowed to stand in the cold overnight , chilled to
5 degrees centigrade , filtered and the crystals of sodium picramate and the filter paper and filter cake
were further dried by placing on a stack of paper blotters . The crystals were dark red prismatic and
very fine granulation , and were used without further purification for the diazotation reaction .
Recrystallization from boiling water may be done to obtain the sodium picramate
in higher purity if desired .

Perhaps one of the more interesting things about DDNP is its formation of a 50/50 eutectic ( density 1.75 )
with picric acid , which will melt below 100 degrees centigrade . See US1428011 .
Another potential use is the coprecipitation of DDNP with nitrated polyhydric alcohols , which does result
in granular form materials that can function as decent intitiators . See GB568109

Disadvantages with DDNP are its light sensitivity and its difficulty to produce in a decent crystalline
form having good density .

[K9]

One thing I don't understand. What would be the problem with boiling the NaOH and sulfur together? That is what I did and I got a dark red solution with no precipitate. The final product from the reaction was the brown amorphous DDNP. I assumed that was just from the second part of the procedure having to do with acid addition and temperature.

[Rosco Bodine]

It has been years since I experimented with the reaction and my notes
did not include this explanation , but IIRC ......

Boiling will expose the polysulfide solution to extensive oxidation
from exposure to the air and result in a lower activity polysulfide containing
more thiosulfate . Boiled mixtures will be more difficult to make and their
composition and performance will be unpredictable . Try the method I
have suggested and compare the yields against the yields from the
polysulfide reagent obtained by boiling .

Another factor I seem to recall is that the reaction producing the polysulfide
requires a lot of heat , and the temperature required cannot be achieved
except in very concentrated solution , which is initially a melt whose melting
point is lowered by moisture , more than it is a solution . The polysulfide
actually forms as a "solid solution" which is a melt then diluted . Too much
water too quickly lowers the temperature before the reaction completes ,
and I do believe a different polysulfide is formed in the more aqueous reaction .
The exotherm is high from the reaction of the dampened solids which melt together
nicely from their own heat of reaction , a reaction which completes
very quickly in a couple of minutes . If water is added too quickly in too
great a quantity it actually quenches the reaction and can even cause the
mixture to set up solid instead of forming a concentrated solution of polysulfide .

[K9]

Alright, thank you for that. When I get around to testing, whch won't be until the summer, I shall try this out. Thank you again.

[Idiot]

BLASTER, How did you granulated your DDNP ? Or it's mix with MHN or other nitrated sugar ? Can you post how you did it ? I can't get my DDNP to more than 1.1g/cc hand-pressed. I tried to granulate it with dextrin ,but attempt failed. Only one good point in that granulation with dextrin that is easy to pour it. So please post your "method"

[Idiot]

BLASTER, How did you granulated your DDNP ? Or it's mix with MHN or other nitrated sugar ? Can you post how you did it ? I can't get my DDNP to more than 1.1g/cc hand-pressed. I tried to granulate it with dextrin ,but attempt failed. Only one good point in that granulation with dextrin that is easy to pour it. So please post your "method"

[Idiot]

BLASTER, How did you granulated your DDNP ? Or it's mix with MHN or other nitrated sugar ? Can you post how you did it ? I can't get my DDNP to more than 1.1g/cc hand-pressed. I tried to granulate it with dextrin ,but attempt failed. Only one good point in that granulation with dextrin that is easy to pour it. So please post your "method"

[BLASTER]

BLASTER, How did you granulated your DDNP ? Or it's mix with MHN or other nitrated sugar ?

What you can see on picture is pure product after filtration. The key to obtain this granular product was already described -

"Afterwards 150ml of 5.5% hydrochloric acid solution is added dropwise (1 drop every 4 seconds) while continuously stirring. Addition of HCl solution must took 2 hours, while temperature of the solution must be held constantly at 25-30°C"
This procedure must be exactly followed!

Literature says, that higher temperature reaction has positive influence on product density and can be rised up to 40°C, but I didn't tested yet preparation at that higher temperature.
Also after long term (two years) storage uder water, the product from first batch has no signs of any degradation and still works like freshly prepared product.

[al93535]

Has anyone tried Blasters synthesis above to make DDNP? It looks like it might be a good one to try. I have tried the one from KIPE several times without success.

I will try it regardless but wondering if anyone has any additional information about it. I now have commercial sodium sulfide, and sodium nitrite so that should help if that was my problem before.

Also since NaOH is soluble in in water 111 grams to 100 ml water, a 35% solution would be 38.85 grams in 100 ml water correct?

Thanks...