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Author: Subject: Trying for Keto-RDX
fredsci93
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[*] posted on 17-12-2021 at 15:46


The reaction mix is supposed to be milky and it does tend to take up alot of volume and froth, especially if the temp it to high since DNU decomposes exponentially faster at high temps into water and laughing gas which I think is the cause of the frothing(photo attached is just after some of the hexamine has been added from my old synth)

IMG_1795-exif-remove.jpeg - 1.4MB

[Edited on 17-12-2021 by fredsci93]
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ManyInterests
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[*] posted on 17-12-2021 at 17:14


It's good that I didn't see anything I shouldn't. So everything was going well until I made the mistake of dumping the last remaining bit of hexmaine.

So the next time I will know (and review these posts). I will make sure I have a 500ml beaker. so I will have enough space for the expansion... or just halve my amount of acids and hexamine and call it a day.

Quote:
Also the nitration mix after a runaway didn’t seem to have any RDX/keto-RDX when I dumped mine into water, the high temps seem to cook the keto-RDX/RDX, but there’s no harm in dumping the mix into water just to see if anythings in it


Yeah but not with this runaway that I had! I noticed that the tempt went from what I assumed to be 15C to 50 C and it started to turn yellow and bubble. My spidey senses said 'this is going to blow!' and I immediately let go of the entire thing and fled. There was no explosion, but the resulting gas cloud was spectacular. I am pretty certain that if I caught even the smallest whiff of that stuff I would be in serious danger. Thankfully I got away and was completely safe.

The thing burned and boiled until there was nothing left was a black residue in the bottom. I guess that's whatever was supposed to be my RDX yield.

[Edited on 18-12-2021 by ManyInterests]
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fredsci93
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[*] posted on 17-12-2021 at 17:29


wow, that's even more intense than my runaway, after the mix spewed gas and acid all over the walls (the gas was probably mostly N2O and nitric acid vapour rather than NO2 since it was uncoloured), a small amount of yellow liquid was left over, my runaway occurred ~1/2 way though my synthesis though, so it must have not generated enough energy to boil everything off since not all the hexamine was added

what sort of burning happened, just charing or full fledged flames?
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ManyInterests
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[*] posted on 17-12-2021 at 19:22


There was massive boiling and gasses spewing out. No flames, no lasting charring (my 1000ml beaker was 100% intact. You gotta love borosilicate glass!!) but imagine something boiling but in ultra fast-motion and it goes from full to empty in a few seconds. That was one hell of an ultra dramatic runaway and my single most dramatic runaway!

I did hear something popping, I thought my beaker busted, but what actually happened was my glass thermometer was what popped. I don't mind... that glass thermometer was already destined for the trash. The first runaway I had had worn out almost all of the numbers so I had no idea what it was indicating other than zero (which was the only number to survive). I had already ordered another 0-100C glass thermometer, but what I will be doing before continuing my experiments in a year or so is order a set of -30-100C thermometers from Aliexpress. They're not that expensive. I will have plenty of spares, and the greater range will tell me just how cold it is when I am at sub-zero temperatures.

This is a pity because based on what you said how the synthesis go, I was doing mostly fine until I dumped the remaining hexamine. The next time I do this if I feel like adding anymore is risky I will just call it a day. The one thing I learned about nitrating stuff is that you can undernitrate things, but you can't overnitrate something. This is why in my ETN synthesis I always put a little less erythitol to the nitrating mix. While this does mean I need to wash the end product more thoroughly, that is a small price to pay for a safer reaction.
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fredsci93
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[*] posted on 17-12-2021 at 20:09


Right, I find the hexamine addition my first time around was super difficult, but on my last run it was much easier and the urea step was the awful part, not sure why, probably down to cooling, or any range of other factors, the reaction is pretty unpredictable and hard to tame, some time in a month or so I'll try another few synths at the scales quoted in the paper, this time with overhead stirring because I noticed there are alot of local heating maxima during the synth which will lower the yield alot.
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[*] posted on 18-12-2021 at 12:17


Fred? Why not use a slushy of dry ice and isopropyl or ethanol?
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fredsci93
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[*] posted on 18-12-2021 at 12:50


The main reason I haven’t tried dry ice/ethanol is because where I live the only place to get dry ice is a BOC gas facility an hour away, it's inconvenient for me and salted ice baths are sufficient for the reaction so long as you replenish them often. It's an interesting idea, if I'm near the dry ice facility I'll grab a bit for a test run.
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[*] posted on 19-12-2021 at 19:59


Quote: Originally posted by fredsci93  
The main reason I haven’t tried dry ice/ethanol is because where I live the only place to get dry ice is a BOC gas facility an hour away, it's inconvenient for me and salted ice baths are sufficient for the reaction so long as you replenish them often. It's an interesting idea, if I'm near the dry ice facility I'll grab a bit for a test run.


Doooooooooooo ittttttttttttt!
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fredsci93
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[*] posted on 19-12-2021 at 20:39


I looked a bit, I’ll probably be a very long time before I try a dry ice reaction, the smallest amounts I can seem to find are 10kg boxes for nearly 90USD, which is a very frivolous purchase for a single reaction, which is a shame, I remember only 2 years ago they used to sell by the kilo :mad: , oh well maybe they'll start selling by the kilo again soon (could have switched during covid?) or maybe I'll get some in a package.
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[*] posted on 20-12-2021 at 07:48


I didn't think of the dry ice and alcohol... I think I can get some in my area. I'll keep that in mind the next time around.
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[*] posted on 21-12-2021 at 05:04


Be aware that it is not always safer to cool a reaction excessively. It is possible to essentially stop some reactions if the temp is too low. This means that when you have added all of your reactants and at some point stop the cooling, the mix will heat up naturally. Then when it gets warm enough to begin reacting, the exotherm will warm it faster and faster --> runaway.

Also, don't freeze your beaker into a block of ice. A stirred cooling bath is much more effective for removing heat, even if the temp of the bath was higher than that of the block of ice.
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fredsci93
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[*] posted on 21-12-2021 at 18:21


that's true, dry ice could be detrimental, the ideal reaction temp during urea additions is between 5C and 0C so dry ice could very easily be detrimental for making the DNU, however the hexamine additions should be done ideally between -5C and 0C and in that case dry ice/ethanol could be useful, but even then it could also lower it to low fairly easily, definitely worth a try if anyone has good access to dry ice.

[Edited on 22-12-2021 by fredsci93]
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[*] posted on 8-1-2022 at 05:44


it seems to me that urea nitrate and hexamine dinitrate would be useful- the process won't be very exothermic. And these organic salts already contain some nitric acid.



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[*] posted on 8-1-2022 at 11:35


Quote: Originally posted by fredsci93  
the hexamine additions should be done ideally between -5C and 0C and in that case dry ice/ethanol could be useful, but even then it could also lower it to low fairly easily, definitely worth a try if anyone has good access to dry ice.
[Edited on 22-12-2021 by fredsci93]


You can easily maintain -5 to 0c just with ice and salt. How long depends on how much ice you have and local temperatures.
You can get gel packs that freeze at all kind of temperatures to help manage your cooling. They are also very useful in distillations (just replace)
Check the different color / temperatures and check how low your freezer will go before purchasing.
Normal freezers will go down to -16c which for me is the blue gel.
That, and good brine can really help. Water will of course freeze around the packs.
They're a good alternative, are reusable (just rinse and put back in freezer).
Oh... and dont put them in acetone ;)




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[*] posted on 3-4-2022 at 09:24


Hello guys,

I just fail to produce Keto-RDX via the 2008 Chinese paper route with H2SO4/NH4NO3 way :-(

1-I mixed 50g of 98% clear H2SO4 + 31g of recrystallized NH4NO3 and putted it in the freezer.
2-Then I've added 5.25g of urea to the cold mixture, unfortunately, I guessed the tiny pearls would dissolve... But don't all of them, 20% remain in pearls...
Probably the temperature was to far below zero...
The reaction is very strange, at first, the mixture is firstly like a soft past, and in 4 secondes, become hard like hard butter ! So strange ! And endothermic furthermore ! Then I managed to hit
this bloc and back it to soften butter with lot of efforts.
3- At -20°C the precedent paste is kneaded again to bring it to very thick slurry.
4- I've added 5g of hexamine wile the mixture was more easy to stir, like a hard paste. First by 0.5grams, then, like the temperature remain to -15°C, all the 5g of hexamine remained.
5- the temperature after 40 minutes was to -2°C (in a ice bath) then, I putted it in 20°C water and stir it again during 10minutes.
6- As the temperature was near 15°C, I poored it in 500mL 5°C water.
7- Almost nothing was precipitaed, only some pearls of urea wasn't still not dissolved...
Sad experiment, but cheap !

Conclusion: even the fact that the temperatures was not exactly the same than the paper, I guess that this route H2SO4/Nitrate is not a functioning way for RDX/K-6 BUT with a really strict method, maybe... Someone could succeed. Maybe.

(for example, I reach 95% yield for ETN since 7 years with this route (1/4/10) and 80% for ETN with 1/5/12 with KNO3)


[Edited on 3-4-2022 by Uriel]
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