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wessonsmith
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You were missing the ETN. Microtek offered a plausible hypothesis on how your hammer blows could miss the ETN, but the hammer did
miss.
ETN's properties don't change with the amount. If you strike 1mg or 100mg of ETN with a hammer against a steel plate, the ETN will detonate.
I can't stress this point enough. ETN is just as sensitive in the 1mg amount as it is in 10g. ETN particle size doesn't change this either. So small
VS large particles will both be as sensitive.
[Edited on 12-7-2019 by wessonsmith]
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twelti
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Quote: Originally posted by wessonsmith  |
Probably best if I just delete my posts. My intention wasn’t to make people uneasy.
[Edited on 12-7-2019 by wessonsmith] |
Hopefully not, your posts are informative and starting useful discussions.
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wessonsmith
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Not all my posts, just the posts pertaining to my plastic manufacture.
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OneEyedPyro
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| Quote: Originally posted by wessonsmith |
You were missing the ETN. Microtek offered a plausible hypothesis on how your hammer blows could miss the ETN, but the hammer did
miss.
ETN's properties don't change with the amount. If you strike 1mg or 100mg of ETN with a hammer against a steel plate, the ETN will detonate.
I can't stress this point enough. ETN is just as sensitive in the 1mg amount as it is in 10g. ETN particle size doesn't change this either. So small
VS large particles will both be as sensitive.
[Edited on 12-7-2019 by wessonsmith] |
Particle size absolutely does matter when it comes to impact sensitivity, this is widely known and well documented.
The physics behind why this is true is simple.
With a fine powder each impacted crystal can more easily impart its energy to other surrounding crystals via friction thus reducing the peak forces
applied to a single area.
With larger crystals there is less surface to share the impact, the crystals drag across each other with more force and see higher peak forces.
This is a big part of why milling powders becomes progressively harder as particle size decreases.
This is why loose sand hurts less to fall on than a loose pile of golf ball sized rocks.
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wessonsmith
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| Quote: Originally posted by OneEyedPyro | | Quote: Originally posted by wessonsmith |
You were missing the ETN. Microtek offered a plausible hypothesis on how your hammer blows could miss the ETN, but the hammer did
miss.
ETN's properties don't change with the amount. If you strike 1mg or 100mg of ETN with a hammer against a steel plate, the ETN will detonate.
I can't stress this point enough. ETN is just as sensitive in the 1mg amount as it is in 10g. ETN particle size doesn't change this either. So small
VS large particles will both be as sensitive.
[Edited on 12-7-2019 by wessonsmith] |
Particle size absolutely does matter when it comes to impact sensitivity, this is widely known and well documented.
The physics behind why this is true is simple.
With a fine powder each impacted crystal can more easily impart its energy to other surrounding crystals via friction thus reducing the peak forces
applied to a single area.
With larger crystals there is less surface to share the impact, the crystals drag across each other with more force and see higher peak forces.
This is a big part of why milling powders becomes progressively harder as particle size decreases.
This is why loose sand hurts less to fall on than a loose pile of golf ball sized rocks. |
There is no appreciable difference. Are you trying to argue that there is a noticeable difference between small and large particle sizes when it
comes to the sensitivity of ETN?
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Rocinante
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The problems in your tests come from the impactors. Those steel surfaces aren't completely flat and thus small samples can hide in those gaps - not
being hit by anything.¨
I had severe problems detonating TATP/HMTD that way.
It is well known that particle size has medium effect on impact sensitivity. But we're talking 50 % or so in most cases. That's why your hand test
don't differentiate between them. But the difference is there.
Also, your PBX machine is no different than those used in the production of Semtex. Still, I wouldn't feel completely comfortable around it. A long
cord and a wall solves that problem.
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twelti
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Uhh, are we talking about particle size or sample size? I don't find my ETN easy to detonate in small amounts with a hammer. Maybe I need a bigger
hammer? Or a larger and more sturdy piece of steel. The one I have is around 3/4" thick, and hammer is a medium sized ball peen.
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wessonsmith
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| Quote: Originally posted by twelti | | Uhh, are we talking about particle size or sample size? I don't find my ETN easy to detonate in small amounts with a hammer. Maybe I need a bigger
hammer? Or a larger and more sturdy piece of steel. The one I have is around 3/4" thick, and hammer is a medium sized ball peen.
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An interesting experiment for you to try is to put some paint on your hammerhead and lightly tap a piece of paper. You will see the actual point of
impact and how small it is as compared to the head size. You will get a sense then of how easy it is to miss a small amount of ETN with the real
hammer blows.
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Microtek
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Another problem with a manually wielded hammer is that it is very difficult to ensure that you hit the anvil at a perfect 90 degree angle. This will
also make it difficult to predict the exact point of impact.
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OneEyedPyro
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@wessonsmith
I'm not sure what the relationship between crystal size and sensitivity is with ETN in particular, but with primaries crystal/particle size is an
important factor and I'd assume the same applies to ETN.
As for hammer testing... I prefer use a rounded surface like a large diameter steel pipe, this allows for a good pinch point even when not impacting
at a perfect 90° angle. A large steel or concrete sphere would be even better.
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wessonsmith
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It does not. There is no appreciable difference for ETN.
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OneEyedPyro
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I'm interested in your reasons for believing that.
Have you heard this elsewhere or done testing?
I've done some fairly extensive sensitivity testing with ETN but that was with the dissolve and crash type recrystallizations which tend to produce
very fine crystals.
I didn't find the friction/impact sensitivity to be too unnerving with that product, but of course ETNs inherent potential for DDT upon strong heating
or ignition is always something to be weary of.
As far as I'm concerned it's a sensitive secondary explosive that demands respect regardless of crystal size.
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MineMan
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My understanding is crystal size influences the sensitivity of all explosives... even insensitive ones like RDX... the smaller the crystal the less
internal stress. This is a known.
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Microtek
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Yes, I also remember reading papers about the sensitivity of RDX as a function of crystal size and shape. I don't remember the exact relationship, but
the trend was that the smaller (and possibly the more rounded) the crystals were, the less sensitive.
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wessonsmith
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| Quote: |
Have you heard this elsewhere or done testing?
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Yes, and yes. I think you guys are missing the operative phrase in my statement "no appreciable." Is there a difference in sensitivity between
melt-cast and powdered, yes. Is it large enough to make a bit of difference to us when using ETN, NO! The same is true for different particle sizes
of ETN.
I think you summed it up for me
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As far as I'm concerned it's a sensitive secondary explosive that demands respect regardless of crystal size.
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My understanding is crystal size influences the sensitivity of all explosives... even insensitive ones like RDX... the smaller the crystal the less
internal stress. This is a known.
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This statement is true, however with ETN, please read above.
I am interested in how you all are achieving you're fine particle size of ETN. The only way I have ever been able to make sub-40-micron particle size
ETN consistently has been to dissolve ETN in warm alcohol and then place the container in a -20C bath and mix the solution until nearly all the ETN
crashes out. Once crashed out, and the ETN reaches -10C, I then directly vacuum filter from ethanol, no water crash.
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solo
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Does anyone know of a green catalyst to make tributylcitrate (TBC).i have found many with imidazoles, ionic solutions , solid acids and zeolites.
I want something with minimal handling and an inexpensive catalyst,that can be recharged and reused.....thanks....solo
Note, ....."different catalysts such as as
phosphotungstic acid,modified silica gel supported
phosphotungstic acid, carbon-based solid acid, solid
superacid SO4 2- /ZnO-TiO2, strong acidic resin, cerium-
dopedmesoporousMCM- 41, acid ionic liquid
and dealuminated USY"
see..."An overview on synthetic methods of tributyl citrate
Xiaoli Zhang"....attached
[Edited on 17-5-2020 by solo]
Attachment: an-overview-on-synthetic-methods-of-tributyl-citrate.pdf (249kB)
This file has been downloaded 290 times
It's better to die on your feet, than live on your knees....Emiliano Zapata.
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Microtek
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That paper seems pretty amateurish (for instance, they do not specify what kind of "carbon-based solid acid" they are using) but of the methods
presented, I think the one with acid ion exchange resin is the most promising. Strongly acid ion exchange resins are cheaply and widely available on
ebay for use in water treatment. Just make sure you get the right kind of resin.
You then treat the resin with strong acid, filter off the liquid and add the resin to the mix of butanol and citric acid. After the reaction, you
filter off the resin, wash it, treat it with strong acid, and it will be ready for another batch.
Another possibility would be to try toluene sulfonic acid as a "carbon-based solid acid". I don't think you will be able to easily regenerate it for
repeated use though.
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solo
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...thank you Microtek, I had found this study and was on route to your suggestion.....
Green and Efficient Esterification Method Using Dried Dowex H+/NaI Approach
Petri A. Turhanen,
ACS Omega
2019, 4, 8974−8984
DOI: 10.1021/acsomega.9b00790
ABSTRACT
The usefulness of dried Dowex H+ cationexchange
resin with or without sodium iodide (NaI) as a
catalyst system for different kinds of esterifications using
carboxylic acids and alcohols as starting materials has been
systematically investigated. The Dowex H+/NaI approach is
very effective, generally high yielding, energy-efficient, and nontoxic, and the Dowex H+ resin is reusable. Since the whole
procedure from start to product isolation is also very simple, these features make the method environmentally friendly. The
method is regioselective, and its potential for separation of valuable carboxylic acids like resin acids from mixtures containing
other kinds of carboxylic acids has been demonstrated. Examples for green and straightforward esterification of highly important
natural amino acids are also presented.
Attachment: Green and Efficient Esterification Method Using Dried Dowex H+_NaI Approach (1).pdf (1.5MB)
This file has been downloaded 395 times
It's better to die on your feet, than live on your knees....Emiliano Zapata.
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