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Author: Subject: Nitrated polyols preferences and others you recommend
Tkuze
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[*] posted on 14-5-2019 at 03:25
Nitrated polyols preferences and others you recommend


Hey guys
Just wanted to get your thoughts and opinions on the overall common nitrated polyols, such as ETN, PETN, MHN. I wanted to have a discussion about the cost effectiveness and prefered properties. My experience:
PETN; a lot of different methods, but I will reference the best method in my experience using the latest study using over 8 highly controlled and specific experimental reactions average yield of 79.8% crystalline needles. 10g PE, 33mL HNO3 (98-99%, D=1.505-1.510g/mL), 20mL H2SO4 (94-98%), ~6mL H20. Cover flask with teflon thermometer adapter to exclude water and keep at 6-8C and add FINELY ground material consistently over 2-3 h ( variable), let stir 30 min after removing ice bath and then heat slowly to 25-27C, turn off heat and let stir 30 min. Cool and dump in ice. Filter and wash with water, warm carbonate, water. Recrystallize using 1:1 EtOH/Acetone ( roughly 5-6mL/g). Problem: prone to runaway reactions if PE addition aliquats are inconsistant or solution is too cold and then taken from ice bath and contains a lot of unreacted material.
ETN: highly controlled and specific experimental reactions average yield of 72%, brilliant crystalline needles. 10g E, 49mL HNO3 (98-99%, D=1.505-1.510g/mL), 44 mL H2SO4 (94-98%), ~6mL( optional)H20. Cover flask with teflon thermometer adapter to exclude water and keep at 8-12C and add FINELY ground material consistently over 2h ( variable), let stir 30 min after removing ice bath and then cool and dump in ice. Filter and wash with water, warm carbonate, water. Recrystallize by dissolving in EtOH roughly (1mL/ wet g) and then dilute with dropwise addition of Na[x]CO3. Filter and Let air dry and recrysyallize again using only EtOH. Problem: uses a bit more acid and can degrade during recrystallization if temperature rises over 65, where two layers form.
MHN: 4 highly controlled and specific experimental reactions average yield of 82.5% fluffy powder. 11g M, 60mL HNO3 (98-99%, D=1.505-1.510g/mL), 80mL H2SO4 (94-98%), Cover flask with teflon thermometer adapter to exclude water, add HNO3 and keep temp below 5C and add FINELY ground material consistently over 30 min( variable) while watching temp as solid dissolves, let stir 15 min and add H2SO4 over 1 h. After 1/3 H2SO4 is added, becomes white and viscous, therefore stir with thermometer. The first half of the addition generates a lot of heat, so use lots of ice. The last of the acid can be added quickly and hand stir occasionally for 30 min. Cool and dump in ice. Filter and wash with water, warm carbonate, water
Recrystallize using 3mL EtOH/g. Problem: solution can become very dark yellow and degrade rapidly if the precipitant isnt broken up and stirred while washing with carbonate in the Buchner funnel. Wash with plenty of water and mix well while filtering. Sometimes it will still turn light yellow during recrystallization. High heat will result in the formation of lower nitrated polyols. Also, requires the most acid.
All work excellent- ETN is the best in my opinion because it can be made quickly and melt casted using a pill bottle and a cylindrical hole can be molded using a tube ( pen or marker works and is easily removed after cooling) for inserting caps. Great for making day before use for stump removal,
What do you guys think about these procedures and qualitative observations.
GOAL: I want to know what other sugar alcohols/polyols you guys have made succesfully and what other cool projecrs I could carry out since I have the above done. Please share any improvements or comments
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Microtek
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[*] posted on 16-5-2019 at 10:46


In my experience PETN yield can be much higher. I prefer doing the nitration with nitric acid of ca. 99% concentration, but no sulfuric acid at all. This has several advantages:

- Yield is close to quantitative (97-99%)

- PE is much more soluble in the mix, and the viscosity is much lower

- The sulfuric acid for concentrating the nitric can be recycled indefinitely

Of all the solid nitrated polyols, I think PETN is by far the best, overall. The combination of moderate sensitivity, high performance, and reasonable stability trumps the castability of ETN in my book, though you could probably find a combination of (possibly energetic) modifiers to reduce the sensitivity of ETN, similar to the PTX I and II formulations (Picatinny Ternary eXplosive).
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Tkuze
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[*] posted on 16-5-2019 at 14:11


I will test your method. Can you give me some more experiemental detail? My preparation manual does have 2 reactions using only 99% nitric acid, but the first requires keeping temp at 40 and the second requires keeping temp under 30C and adding over one hour. I believe i tried this but added over a longer period and it still had a runaway. Would the procedure be similar to that of hexamine ==> RDX? Thanks
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Herr Haber
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[*] posted on 17-5-2019 at 05:06


The addition time is way longer than needed in most procedures I saw.
As long as you have adequate cooling and agitation you can do that much faster. Just keep in mind that if you nitrate 30 grams of PE you'll give off more heat so the procedure you had say for 10 grams will have to be adapted.
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Tkuze
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[*] posted on 17-5-2019 at 15:48


Thanks. I have tested the addition times using multiple controlled experiments. The yield only seems to go down about 7% with longer addition times, but I found 2 hours is adequate and avoids runaways. PE is the only real problem. Having tested over 40 reaction variations, it is a bit hard to add so fast and ensure no runaways. The problem I find is the temp of addition. Too cold and after addition and letting warm to 25C, it all reacts. Keeping about 7C and slpw additon ensures no runaway and that everything reacts. You are correct in your statement, but my philosophy is I would rather get a 75-80% yield( after 2x recrystallization and drying) than a runaway and no product and the shame of wasting material. Do you have any advice on RDX improvement? Always get a 50% yeld using pure reagents (rxn has little runaway protential). In some official industrial procedures, they advise dissolving in HNO3 and then adding warm 70% HNO3 with NaNO2 at 60C. This results in evolution of NxOx and doesnt seem efficient. Also, HN03 has consistent density of ~ 1.51and a clear, very suble tint of yellow, so little nitrogen oxides. It is distilled with anhydrous salt and 98% H2SO4 at 83C. The distillate is collected in fractions and density tested at 20C to make sure the purest acid is collected. Fractions with anything less than 98% are collected in separate bottle and used for dilution in reactions using 70% HNO3.

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Microtek
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[*] posted on 19-5-2019 at 10:51


Colour is an uncertain way to judge the NOx content of nitric acid, if it has any colour at all. WFNA should be indistinguishable from water, when only looking at the colour. One way to achieve this is to pass pre-dried (CaCl2 or sulfuric acid) air through it at a temp of 50C. You can also add urea (again, at 50C), though I don't like this method as it also dilutes your acid.
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Herr Haber
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[*] posted on 19-5-2019 at 12:53


Quote: Originally posted by Microtek  
Colour is an uncertain way to judge the NOx content of nitric acid, if it has any colour at all.


https://en.wikipedia.org/wiki/Nitrogen_dioxide

The picture illustrates that quite well :)
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[*] posted on 21-5-2019 at 12:05


https://onlinelibrary.wiley.com/doi/pdf/10.1002/prep.2018003...

XPN is twice as sensitive as ETN or PETN to friction, so it is still quite safe yet the greater sensitivity may indicate that it will undergo DDT easier than ETN.

This might be a nice project for Dr. Liptakov.
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Microtek
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[*] posted on 22-5-2019 at 00:28


From the preview of that paper:


Quote:

Comparison of mean activation energies indicated that all species shared common decomposition pathways, but analyses of critical temperatures of thermal decom-position revealed XPN as one of the least stable nitrate esters.


Which would probably make XPN less attractive despite the cool abbreviation...
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[*] posted on 22-5-2019 at 07:23


it is less stable but in much the same way as ETN is less stable than PETN, not a big deal

also, it could be utilised in a "NPED" stab type detonator
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Microtek
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[*] posted on 22-5-2019 at 08:56


Note that it is not the sensitivity they are talking about, but rather the thermal decomposition temperature.

In this paper, the critical temperature of XPN is found to be 140C while sorbitol hexanitrate has 161C.

The thermal stability ranking of the nitric esters they examine is found to be: MHN<XPN<TMPTN<SHN<NIBGT<ETN<PETN<DiPEHN

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[*] posted on 22-5-2019 at 13:36


thermal stability is directly linked to impact sensitivity and moderately to friction sensitivity
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[*] posted on 22-5-2019 at 22:24


Did anybody try to make hexanitrosorbitole?



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FeedMe94
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[*] posted on 22-5-2019 at 22:55


I have plenty of Mannitol Hexanitrate ( MHN ) but its have been said that you cannot achieve to have pure hexanitrate. Lower esters will be present like pentanitrate and tetranitrate
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[*] posted on 22-5-2019 at 23:13


Quote: Originally posted by FeedMe94  
I have plenty of Mannitol Hexanitrate ( MHN ) but its have been said that you cannot achieve to have pure hexanitrate. Lower esters will be present like pentanitrate and tetranitrate


I was so stupid that when I saw sorbitol in shops (as a replacement for sugar) I didn't make the corresponding experiment. Now I have no chems no lab vessels- the only available chem is Ca(ClO)2.




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