Sciencemadness Discussion Board

AP dimer-Trimer Seperation

StevenRS - 20-1-2008 at 12:30

I know AP has been beaten to death, and no one wants a new thread about it, but this is important. (I think, at least)
The dimer is a unwanted product of AP synthesis, and is unavoidable. But is widely used, regardless of its dangers.
The removal of ALL dimer AP makes AP much more stable. (relatively)
How do I know this? I did it.
Its simple to remove, Trimer sinks in water, Dimer floats.

Zinc - 21-1-2008 at 01:05

When I make AP most of it forms at the bottom of the beaker but some of it floats on the surface. So I just throw away the top layer and end up with pure trimer?

12AX7 - 21-1-2008 at 05:41

On a similar subject, what is the configuration of MEKP? Is it a cycle like TATP? Is it 1,2,3-cis or 1-trans in its preferred configuration? Does it fold at all?


zeppelin69 - 21-1-2008 at 07:51

I am fairly sure that just because the AP is at the bottom of your beaker it doesn’t mean that it is pure trimeric nor are the crystals floating at the top pure dimeric. I have left AP in a container sit at room temperature for a few hours, and noticed that small crystals will constantly float up to the top, and sink to the bottom. Also, both isomers are considered to have a density of 1.13g/cm3.

There has been talk of separation through sublimation, but I doubt this will work either because of the similarly wide temperature that both isomers sublime.

I believe MEKP is cyclic, I have read patents that call for polymerization through cyclic ketone peroxides and most use MEKP.

[Edited on 21-1-2008 by zeppelin69]

StevenRS - 21-1-2008 at 09:48

The constant bobbing effect is probably due to bubbles forming on crystals, causing them to float.

I did several tests to confirm this, like making a batch a high temperature, and much more floated; and a batch at low temperature, and less floated. The two layers also display a significant difference in sensitivity.
Also I heard that the dimer form is more easily decomposed by highly alkaline solutions than the trimer.

Boomer - 24-1-2008 at 10:15

"... a batch a high temperature, and much more floated; and a batch at low temperature, and less floated"

PETN should be really heavy compared to water (TMD 1.78 IIRC). Right?

Put it in a blender with lots of water, and guess what? It all floats in the end.

Your batch formed crystals faster, hence smaller. Keep TATP *under water* in a fridge for two years - it forms crystals coarse as sugar. Let a solution in acetone evaporate through a small neck over a month - you get crystals up to half a centimeter.

Now take one of these dangerous monster crystals and grind it with a hammer on an anvil with progressive force - it gives a fine powder, *then* detonates at approx the same force that freshly prepared material needs.

Then finally when you carefully pour your so-much-safer trimeric TATP from a folded paper into a pipe - watch your fingers turn to red mist. That's not science, it's coincidence. Call it gambling. You'll never get it safe enough to be anything but a primary explosive, and these have killed and maimed the most experienced researchers over the last two centuries. Use in centigram quantities if you want to grow old.

Rosco Bodine - 24-1-2008 at 11:01

Using HCl as the acid catalyst only the trimeric form of
AP results . Using SnCl2 or SnCl4 as the catalyst , only the tetrameric form of AP results , IIRC . Using H2SO4
as the acid catalyst and warm temperatures , a mixed
dimeric and trimeric form , having a small percentage of the dimer results . IIRC all of this has been covered
a few times before either here and/or at other forums ,
along with the mythology about neutralization of acid
as being necessary for stability of AP , when in fact
acid acts as a stabilizer , and beyond that that AP and
MEKP as well for that matter are reasonably stable at
ordinary temperatures indefinitely , when kept in inert
and unreactive containers . Many people seem to equate
"reactive" or "explosive" with "unstable" as if the terms were interchangeable equivalents which they are not .
AP and MEKP are not "unstable" and their stability is not
adversely affected by traces or even larger amounts
within reason of acids , but AP and MEKP are most definitely both explosive and reactive , the MEKP moreso
with regards to reactivity ....while both are reasonably
stable at ordinary temperatures .

BTW the tetrameric AP is the most stable and also the most explosive of the three .

[Edited on 24-1-2008 by Rosco Bodine]

kiknet - 24-1-2008 at 13:05

I had an unusual occurrence with AP once, I used an excess of H2O2 (6%) and the acid I used Diggers brand HCl (which is the most common one in Australia) has a 1% Titanium Dioxide additive which I believe causes problem when using the standard ratios for synthesizing AP, normally I use and excess of Acetone(250ml of H2O2 with 100ml of Acetone) and it works out fine however this time with the the large excess of H2O2(250 H2O2 with 50ml of Acetone) and the Diggers brand HCl the formation took days and I had a very very poor yield which, even though perfectly dry, exposed to flame, fizzled and burnt rather slowly instead of the characteristic whoompf! rapid deflagration of AP leading me to believe I had synthesized a large amount of dimeric AP perhaps?

zeppelin69 - 24-1-2008 at 13:08

Have you personaly made tetrameric Rosco? I attempted it about a year ago with SnCl2 and got an extremely fast ppt. of dimmeric. The crystals were enormous and upon deflagration it had much weaker "puff" than with my usual trimeric. Also I dont believe HCl will always yeild trimeric, this greatly depends on the temperature while the reaction takes place.

Rosco Bodine - 24-1-2008 at 16:38

Yes I have made the tetramer using SnCl2 .

The SnCl2 was introduced in a fine stream through a hypodermic syringe into the H2O2 + acetone mixture
rapidly stirred . The reaction was violent and made an audible crackling sizzling sound as the SnCl2 solution
was introduced .

The product was the tetramer , by crystalline form ,
vapor pressure , and explosive power and IIRC also by
solubility and melting point .

[Edited on 24-1-2008 by Rosco Bodine]

zeppelin69 - 24-1-2008 at 17:10

How were you able to add it through a syringe? was it dissolved in something? When I added my SnCl2, it was a solid but it also made a hissing/popping sound (much like concentrated H2SO4 except more so). Was your reaction done at room temp as in the patent?

StevenRS - 24-1-2008 at 17:35

I never suggested AP was even remotely safe in any form. All it takes is one dimer crystal to ruin your day in a supposedly dimer free batch, but removing as many as possible would make is better. Every single added safety precaution helps prevent that one, maiming accident. This is not a substitute for common sense of anything else, it just helps.

Rosco Bodine - 24-1-2008 at 18:19

SnCl2 was added as solution of course .

This whole thread is predicated on a false premise
and a scientifically invalid assertion and is really beneath
the level of discussion for this forum based on the one correct first thing said in the opening post , which is that this topic already is for some years already passed actually , indeed a dead horse which needs no further beating .

zeppelin69 - 24-1-2008 at 18:24

What was the SnCl2 dissolved in? water? Did you buy it reagent grade, or make it yourself? I may give this synthesis another try..

Boomer - 25-1-2008 at 08:31

"All it takes is one dimer crystal to ruin your day"

Again, even if it's all trimer, confirmed on every single fucking crystal by X-ray, and the water in the acid has been blessed by the pope, it may explode while pouring it from a folded paper, when it normally takes some rough grinding between hammer and anvil.

It's not the friction, not acidity, but more likely static, and possibly triboelectric effect. Or maybe it only happens when Madonna has her period. Don't ask me, I do know it is perfectly stable chemically, still I will not handle more than a gram at a time, and this comes from a guy who smokes in the lab, and has no problem walking around with a 50ml-bottle of nitro in the jeans pocket.

gregxy - 25-1-2008 at 09:16

The best rule is that "If it is sensitive enough to be a primary
explosive it is sensitive enough to go off some time when
you don't expect it". The real problem with TATP is that it is
easy to make. So you have many more people making it and
in unsafe quantities. If Lead azide and mercury fulminate
were as easy to make I suspect there would be just as
many accidents with them. From COPAE "lead azide crystals
more than 1mm in length can explode spontaneously from
the internal stress"

Purity and stability are more issues for commercial or military
applications where long term storage is needed, and the
problem is most likely that the primary will slowly degrade
and become inert.

[Edited on 25-1-2008 by gregxy]

quicksilver - 4-2-2008 at 05:07

This whole thread -=IS=- developed on a false premise and a scientifically invalid assertion because it has not and cannot happen, been proven or even have sense to it. The Dimer "FLOATS"? ....This reminds me of tales of "Spanish Fly" in my high school days.