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quicksilver
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Quote: Originally posted by Vikascoder ![](images/xpblue/lastpost.gif) | Quicksilver I have made picric acid But the problem comes in increasing its sensitivity . Will any one please give valuable knowledge no the topic
how to increase the sensitivity of picric acid so that it can be easily initiated without providing lots of confinement. |
I would simply underline what Bot0nist had said.
With ~MOST~ nitrated phenols it takes some well practiced lab-skills to get the sulfonation, time, & temp just right. The majority of
"TRI-nitrated" phenols have some lower nitrated material in your yield.
The trick is to find just what it is that is getting a much lower percentage of DI-nitrated yield. Once you manage that, the level of impact
sensitivity goes very high (especially with TNP).
But realistically it can be several things. Try not to make any alteration without notes or two or more alterations at a time. What helped me a great
deal is working with small quantities. This allows for greater control. Frankly In MOST ALL of my experiments I work with very small amounts. It
provides a serious level of safety, it gives much finer level of HNO3 purity, it is easier to maintain temp.
There ARE several things that don't do well with scaling up or down but esters and (poly)phenols are generally fair sailing.
Once you get (TNP) to "pop" with impact, the level of true TNP vs. DNP simply HAS to be substantially higher. This is a very crude way of expressing
it but if you TNP is of a VERY LIGHT yellow and has well formed crystals; you should be going in the correct direction.
I have heard of attempts at TNP with WinterGreen Oil, and I personally have worked with crushed horn and (organic) Indigo. TNP is actually NOT too
tough to synthesize, however one does need the correct proportions of HIGH percentage HNO3, temp and exposure (stirring).
IF you are working with a solid nitrate for your HNO3 then make sure your NaNO3 is well crushed and purified, both potassium and ammonium nitrate will
mix easier that sodium nitrate but sodium nitrate requires less to achieve the same % of HNO3.
IF your product is dark that may indicate a higher hydrogen level. BOTH TNP & DNP will produce energetic heavy metal picrates however. The most
productive means of mfg lead picrate is the use of lead nitrate and following the methods to mfg ~BASIC~ lead picrate. Normal lead picrate takes a bit
of care and is less energetic - aside the poorly defined "exposure-method" of mixing PbO & a picric acid requires a much more definitive synthesis
that that proposed in those charming military cook-books.
[Edited on 12-6-2012 by quicksilver]
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caterpillar
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Quote: Originally posted by VladimirLem ![](images/xpblue/lastpost.gif) | Quote: Originally posted by Vikascoder ![](images/xpblue/lastpost.gif) | I need to make picric acid more sensitive for my purpose . You are correct caterpillar that in detonator it should be used as it is . But for my
purpose i need to make it more sensitive . So please suggest some ways to make it more sensitive |
hm...maybe some percents of ammonia nitrate ?
hm...TNP is an acid...could be a bit dangerous?!
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No. One great NO. AN doesn't make TNP more sensitive, but you'll surely get some trace amount of nitric acid in such mixture. Self-acceleration
reaction may occur- you'll get if not explosion, but violent burning. AN can be safely mixed with ammonium picrate, but this mixture is less sensitive
than pure TNP.
Women are more perilous sometimes, than any hi explosive.
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VladimirLem
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Quote: Originally posted by caterpillar ![](images/xpblue/lastpost.gif) | Quote: Originally posted by VladimirLem ![](images/xpblue/lastpost.gif) | Quote: Originally posted by Vikascoder ![](images/xpblue/lastpost.gif) | I need to make picric acid more sensitive for my purpose . You are correct caterpillar that in detonator it should be used as it is . But for my
purpose i need to make it more sensitive . So please suggest some ways to make it more sensitive |
hm...maybe some percents of ammonia nitrate ?
hm...TNP is an acid...could be a bit dangerous?!
|
No. One great NO. AN doesn't make TNP more sensitive, but you'll surely get some trace amount of nitric acid in such mixture. Self-acceleration
reaction may occur- you'll get if not explosion, but violent burning. AN can be safely mixed with ammonium picrate, but this mixture is less sensitive
than pure TNP.
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hm...okay^^ good 2 know
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Vikascoder
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@quick silver :
i use powerlabs method for making picric acid just i substitute phenol with A.S.A and use 98%H2SO4 and 70% HNO3. then for finalising the product i
recrystallizes it from wather and hydrochloric acid (since rosco bodine told about it in the thread picric acid :different instruction )
i have one more question to ask about picric acid
as lamda told in the thread picric acid :different instruction
Finalising the production stages and purification of Picric acid.
Picric acid can be purified by:
1. - Washing the filtered crystals with a little amount of cold Water.
2. - These washed crystals are then dissolved in a solution of Sodium carbonate (Na2CO3). A Sodium picrate solution is thus formd.
3. - This Sodium picrate solution is filtered, and Hydrochloric acid is then added. Picric acid then crystalises out as yellow precipitate.
4. - This is then dissolved in the minimum amount of boiling Water, filtered, and then cooled. Picric acid will then precipitate.
5. - The crystaline Picric acid thus obtained, is dried at 30 - 40 degrees C..
does this method gives very pure picric acid ?
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Swede
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How about checking the melting point of the sample?
TNP melts sharply at 122.5 C. 2,4 DNP melts at 108 C. Place a fleck into a melting point apparatus and slowly bring on the heat. If the sample
remains strongly solidified well beyond 108 and only begins to liquify at 122 C or so, the sample should be relatively pure TNP. If you have a sad
little puddle at 110 C, then the product is DNP.
A mixture of the two is going to produce a protracted melt somewhere between 108 and 122. The sharpness of the melt is a reasonable sign of purity.
Obviously one wants to use a correct apparatus and extremely small crystalline samples.
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quicksilver
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IF you have access to a workable to a melting machine: I'd think that the best. If you wash and you see a substantial diminishment in weight - again
you have a good % of DNP. Mix and match. What you have the ability to work with effectively - use it. But if you feel there is a real question of
reliability: study the techniques till you find one that you believe will yield accuracy.
The concept is reliability on those techniques that really are consistent Repeatability will give a great deal of comfort..
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Swede
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Agreed and understood. Having a melting point apparatus is a real asset in a home lab.
A while back, in need of a MP device immediately, and being a bit cheap, I made one that in the end performed much better than I expected, although it
uses (in its current incarnation) a naked flame.
A bar of aluminum is secured, maybe 25mm x 10mm x 150mm. In the end, drill a tiny hole perhaps 10mm deep, as close to one surface as possible. Into
this goes a type K thermocouple, coated liberally with heat sink compound.
The bar is placed in a vise or by some other means, is held horizontally. The sample is placed on the bar surface directly above the thermocouple. A
common alcohol lamp provides the heat. By placing the lamp far away from the sample, the heat transfer down the bar and into the sample is very slow,
maybe 1 degree C every 4 to 5 seconds. Moving the lamp closer creates a faster heat rise. In this way, it can be adjusted easily.
The mass of the bar is what makes it work. The entire bar gets heat soaked and prevents spikes to the sample. Using a cover glass over the sample
makes it more accurate, but even without a glass, using known pure salts I verified the function of this rig to within 1 degree or so, assuming the
thermocouple rig is accurate.
There are other threads describing better DIY MP rigs. Common sense applies - tiny samples, and the alcohol lamp can be replaced with an electric
heat gun, or even better a cartridge heater installed into the bar and attached to a variac or some other control.
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quicksilver
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Heat-gun could be excellent - IF you have a method of measurement. Some thought and creativity could yield a very workable device!
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Hennig Brand
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I like the idea of a melting point apparatus. Now that I have read the last few posts I have more of an idea about how to build one.
Mixtures of two different substances can often have melting points that are below either of the pure samples. Mixtures of TNP and DNP were routinely
melted on a hot water bath and then cast. The ability to be melted on a water bath gave these explosives a huge advantage over pure Picric Acid. They
were however more insensitive and less powerful than pure picric acid.
The TNP-DNP equilibrium data table, shown below in pdf, was taken from the following journal.
THE EQUILIBRIUM DIAGRAMS AND CRYSTALLIZATION VELOCITIES OF THE SYSTEMS: (a) PICRIC ACID – 2,4-DINITROPHENOL; (b) DINITROPHENOL – TRINITROTOLUENE;
(c) PICRIC ACID – DINITROPHENOL – TRINITROTOLUENE
Author: A N Campbell; E J Pritchard
Canadian Journal of Research, v25b n2 (194703): 183-197
Attachment: Picric Acid - Dinitrophenol Equilibrium Data.pdf (59kB) This file has been downloaded 742 times
The following pdf is a few lines from the "British Textbook of Explosives" from the section on Picric Acid. It briefly describes the explosive
Shellite, which is a mixture of TNP and DNP and could be melted on a hot water bath. According to the above journal, Shellite was 60% TNP.
Attachment: Shellite.pdf (76kB) This file has been downloaded 662 times
[Edited on 27-6-2012 by Hennig Brand]
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Hennig Brand
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Shellite 60/40 was used, but it seems that Shellite 70/30 was more common after WWI. There seem to be many more references for Shellite 70/30 floating
around. Googling Shellite 70/30 displays many hits.
I found an interesting bit of reading on Shellite, in the following text, which explains a little bit about why the 60/40 and 70/30 compositions were
chosen.
Warship
By John Jordan, Stephen Dent
Here is a snip-it from the text.
Attachment: Shellite Evolution.pdf (134kB) This file has been downloaded 794 times
[Edited on 5-7-2012 by Hennig Brand]
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al93535
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Can I take a yield of mostly dinitrophenol, and nitrate it further to TNP? Or is there some danger I am overlooking?
I would like to add the DNP to cold 98% sulfuric, and cautiously add 95% hno3. Then warming the mixture just as in the original synthesis for TNP,
stirring and letting it sit.
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Hennig Brand
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The best use of time and other resources, I think, is to run a strong single stage nitration right through to TNP. I have never done it, but I don't
think it would be a problem to start with DNP though. Actually, once those first two nitro groups are on the ring, it should be much less sensitive to
oxidation/degradation.
Read the section on Picric Acid from "The Chemistry of Powder and Explosives", I think there are processes described that involve nitrating DNP to
TNP. The COPAE is available for download from the forum library.
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Bot0nist
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Quote: Originally posted by Hennig Brand ![](images/xpblue/lastpost.gif) | I like the idea of a melting point apparatus. Now that I have read the last few posts I have more of an idea about how to build one.
Mixtures of two different substances can often have melting points that are below either of the pure samples. Mixtures of TNP and DNP were routinely
melted on a hot water bath and then cast. The ability to be melted on a water bath gave these explosives a huge advantage over pure Picric Acid. They
were however more insensitive and less powerful than pure picric acid.
The TNP-DNP equilibrium data table, shown below in pdf, was taken from the following journal.
THE EQUILIBRIUM DIAGRAMS AND CRYSTALLIZATION VELOCITIES OF THE SYSTEMS: (a) PICRIC ACID – 2,4-DINITROPHENOL; (b) DINITROPHENOL – TRINITROTOLUENE;
(c) PICRIC ACID – DINITROPHENOL – TRINITROTOLUENE
Author: A N Campbell; E J Pritchard
Canadian Journal of Research, v25b n2 (194703): 183-197
The following pdf is a few lines from the "British Textbook of Explosives" from the section on Picric Acid. It briefly describes the explosive
Shellite, which is a mixture of TNP and DNP and could be melted on a hot water bath. According to the above journal, Shellite was 60% TNP.
[Edited on 27-6-2012 by Hennig Brand] |
Thank you Henning. You're really an asset to the EM section, IMO. I had overlooked that table. I have, in the past, rigged melting point apperatus
connsisting of a small brine or oil bath with slow mag stirring, a thermometer in the bath, as well as a laser surface temp reader pointed at a small
foil "boat," secured with thread, that held the sample. I really like the heat gun idea though.
IME, impact testing is an easy and pratical way to determine if your TNP will preform as needed in a booster or compound cap.
[Edited on 11-7-2012 by Bot0nist]
U.T.F.S.E. and learn the joys of autodidacticism!
Don't judge each day only by the harvest you reap, but also by the seeds you sow.
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Hennig Brand
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Thanks, I still need to learn more general chemistry, but I know a lot more than I did three years ago.
The oil bath method sounds good. I have a bunch of large nichrome wire that I salvaged from a scraped industrial sized heating/cooling system. With an
aluminum bar or other suitable thermal mass, and a descent variable power supply, good temperature control should be achievable. It would also be very
clean and convenient. The nichrome wire will probably need to be insulated from the thermal mass, since the thermal mass will most likely be
electrically conductive as well as thermally conductive. I was thinking of drilling a hole length wise through the thermal mass and lining it with
thin glass tubing. A straight length or small coil of the nichrome wire would go through the glass tubing/liner. If aluminum was used for the thermal
mass it should work, since aluminum expands much more than glass when heated. There is probably a better way to set it up, and I am still thinking it
over. I think some type of electrically controlled heating element would be ideal though.
There are lots of ways to design a melting point apparatus and each design will have various pros and cons.
I am definitely going to do melting point tests on some of my TNP samples in the near future. I am very curious now.
[Edited on 11-7-2012 by Hennig Brand]
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Swede
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If you do pursue a MP apparatus, my recommendation would be to use a thermocouple. Thermocouple meters are very useful beyond a MP rig... the
business end of a type K thermocouple in it's uncoated state can deal with jet engine temps, 1,000 deg. C and more, and also, the thermocouples are
available coated with inert materials like PTFE.
A simple meter costs maybe $20, has big digits, and can be read at a glance or from a distance, a nice feature when your hands are busy, or are
doing a nitration. As far as accuracy, no, they are not going to match a good lab glass thermometer, but for 98% of what we do, it's good enough.
Anyway, get a meter and two or three thermocouples. One for high temps (inconel sheathed), one "normal" for something like a MP setup, and a third
for immersion in acids and the like.
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Hennig Brand
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A thermocouple probe and meter would be the right idea. I have a couple of cheap units, that are part of multimeters, but their accuracy is
questionable. I know that there are very good ones on the market though. Like you say, the cheap meters may be good enough. A dedicated device might
be a better bet than one that is part of a multimeter also.
A low ohmic value power resistor could be used to heat a piece of aluminum plate. Two power resistors, one attached on either side of an aluminum
plate or block, would be a better configuration though. Small, high wattage aluminum power resistors are available, which are designed to be easily
attachment to a heat sink. I think they could be used to heat a small aluminum plate up to 120C or so without a problem (I am still investigating).
They are in nice convenient packages and already are very well insulated. I am sure this constitutes resistor abuse, but they should last a while,
especially with only occasional use.
[Edited on 12-7-2012 by Hennig Brand]
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Swede
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Hennig, you may want to consider a cartridge heater for your heat source. I looked into these things when I was doing lead dioxide plating as a
compact source of a LOT of heat. These things are cheap, and come in sizes from less than a pencil, to as big as needed for anything we'd do. There
are surplus units on eBay and other places.
If you need to get to 200 or 300 C, I'm afraid the resistors would cook. Just a thought.
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Hennig Brand
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I just googled cartridge heaters and they do look like they would be the proper thing. Power resistors might still be acceptable though, especially if
one only needs to go to 120C or so. Power resistors are very common and cheap and can be found surplus quite easily.
The Picric Acid - DNP equilibrium data table I posted a few posts up has the freezing points of TNP-DNP mixtures, but what I meant to post was the
melting point table from the same journal. The following pdf has Picric Acid-DNP melting point and freezing point tables from the journal previously
referenced.
Attachment: Picric Acid - DNP Melting Points and Freezing Points.pdf (107kB) This file has been downloaded 687 times
[Edited on 12-7-2012 by Hennig Brand]
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Hennig Brand
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Edit:
Someone following this may want to use only the first table and corresponding equation. I think the melting and freezing points should actually be
very nearly the same however, between the two tables, the differences can be quite large. The authors of the journal admit that the samples of picric
acid used were not 100% pure, but were very good commercial samples. This was claimed to be deliberate, in order to better represent real life
commercial material.
The two data tables above only give melting and freezing point data in increments of 10% Picric Acid (more or less in some cases). I plotted the last
5 points from each table (after the eutectic point), using Excel, and was able to get second order or quadratic equations which represent the data
very well. I have made a pdf of the two graphs with quadratic equations and R squared values included.
Attachment: Plotted Data and Equations for TNP-DNP Melting Points & Freezing Points.pdf (171kB) This file has been downloaded 739 times
Ok, I have just done a first crude melting & freezing point determination on a sample of Picric Acid made from aspirin. I basically used a crude
version of the type of setup described above by Swede. Here is a picture of my first crude setup.
![Crude Melting point Apparatus.JPG - 161kB](https://www.sciencemadness.org/whisper/files.php?pid=254023&aid=19475)
A long, narrow length of aluminum plate was used. A small hole was drilled, in the side of the aluminum strip, for the thermocouple probe just below
where the sample to be melted will be placed. One end is held in the large pliers shown, and the other is gently heated with a low flame on a propane
torch.
Using the quadratic equations from above, and the melting and freezing point values obtained from the first crude test, Picric Acid concentrations
corresponding to both the melting and freezing points were easily calculated.
The melting point equation, obtained graphically, is as follows:
y = 0.0092x^2 - 0.8425x + 68.016
Where,
y = Percent Picric Acid
x = Melting Point in degrees Celsius
The freezing point equation, obtained graphically, is as follows:
y = 0.0044x^2 + 0.1199x + 21.45
Where,
y = Percent Picric Acid
x = Freezing Point in degrees Celsius
The temperature values collected from the first crude test were as follows:
Melting Point ~ 120 C
Freezing Point ~ 117 C
Using the equations above, the following Picric Acid concentrations were calculated:
From melting point equation:
Picric Acid concentration = 99.4 %
From freezing point equation:
Picric Acid concentration = 95.7 %
An average of the two was taken giving a result of 97.6 % Picric Acid.
The difference between the melting point and freezing point experimental results is very large. It is very likely that the melting point was overshot,
because very slow accurate control of the heating was difficult. It was noticed that the thermocouple probe and meter used measured lower, by more
than two degrees, than a good mercury thermometer at room temperature before the first test. A better thermometer would most likely make a tremendous
difference in the accuracy of the results. The other equipment as well as the experimental technique will also be refined in the near future.
As even very small proportions of Dinitrophenol in a Picric Acid sample can dramatically change the overall sensitivity, accurate measurements are
very important. This is especially important when Picric Acid is used in small charge size, as in a compound cap.
[Edited on 12-7-2012 by Hennig Brand]
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Hennig Brand
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It was stated in the above 1940's journal that the Picric Acid used during testing was a very good commercial sample, but was not 100% pure. From
modern literature we know that pure Picric Acid melts at 122.5C, but in the melting point table above the value given for 100% pure Picric Acid is
121.0C. If we assume that the experimental method was good, and that the data was carefully collected for the above journal, we should be able to
adjust the above equation and obtain one for actual pure picric acid.
An R squared value of 0.9986, which is very close to 1, is a strong indicator that the data taken from the melting point table above is good data.
We know that the value for 100% pure Picric Acid should be 122.5C not 121.0C, so we can do a horizontal translation to better represent actual pure
Picric Acid.
The original melting point equation which was obtained graphically:
(based on melting point of 121.0C for pure TNP)
y = 0.0092x^2 - 0.8425x + 68.016
Performing a horizontal translation to the right, of 1.5 Celsius, gives the following equation:
(correcting for actual melting point of 122.5C for pure TNP)
y = 0.0092(x-1.5)^2 - 0.8425(x-1.5) + 68.016
or
y = 0.0092x^2 - 0.8701x + 69.3004
I obtained a melting point of 120C in the above crude experiment, which gave a calculated value of 99.4% Picric Acid using the original equation.
Recalculating using the new equation gives a value of 97.4% Picric Acid. As was said above this experimental value is most likely still high, as the
melting point was probably overshot by a small amount.
The 117C freezing point from the above experiment is probably closer to the actual melting point. The aluminum strip cools quite slowly, so obtaining
an accurate freezing point is probably more likely than obtaining an accurate melting point with the simple setup used. Using the new equation, 117C
corresponds to 93.4% Picric Acid. If accurate, this could explain the greater than expected insensitivity of my Picric Acid.
[Edited on 13-7-2012 by Hennig Brand]
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Hennig Brand
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I apologize for the multiple posting, but I thought I should make a correction to the previous posts.
I stated above that I thought the melting and freezing points for Picric Acid -DNP mixtures should be fairly close to one another. It looks like I was
wrong. Apparently it is normal for TNP-DNP mixtures to have melting points and freezing points that differ by several degrees Celsius.
Have a look at the following section on Picric Acid from the text, "Commercial Organic Analysis". The section discussing melting and freezing points
starts near the bottom of page 8.
Attachment: Picric Acid excerpt from Commercial Organic Analysis.pdf (515kB) This file has been downloaded 1321 times
[Edited on 18-7-2012 by Hennig Brand]
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detonator
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Dry and relatively pure picric acid, can be HMTD detonate.
Use 0.2g HexaMethylene Triperoxide Diamine enough to detonate 1g of picric acid.
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Vikascoder
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Could someone help me to nitrate dinitrophenol to trinitrophenol and i have only 70% nitric acid not of further more concentration. (i have other
necessary chemicals readily available-)
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killswitch
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Someone mentioned color. My picric acid is a bit yellowish, but I don't know if it's too yellow or if it's approximately right.
Note: the powdered form seemed considerably lighter in color.
<a href="http://www.flickr.com/photos/70236988@N08/7139432207/" title="TNPcrystal by HNIW, on Flickr"><img
src="http://farm9.staticflickr.com/8152/7139432207_bd3c74bc0a.jpg" width="500" height="375" alt="TNPcrystal"></a>
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caterpillar
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Quote: Originally posted by Vikascoder ![](images/xpblue/lastpost.gif) | Could someone help me to nitrate dinitrophenol to trinitrophenol and i have only 70% nitric acid not of further more concentration. (i have other
necessary chemicals readily available-) |
Convert your diluted nitric acid to K- or Na- salt and mix this salt with sulfur acid.
Women are more perilous sometimes, than any hi explosive.
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