Sciencemadness Discussion Board

Ratio HNO3 H2SO4 for PETN

marc121 - 10-5-2017 at 13:47

Hello, I am new and I would need information about the synthesis of the PETN, in particular on the ratio HNO3 (90%) and H2SO4 (98%) and PE, taking as example 10 gram of PE.
I'm afraid I'm wrong.
thank you

NeonPulse - 10-5-2017 at 14:30

You really need to search this forum. I highly doubt you will be spoon fed such easy to find information. It's all here. Just put PETN synthesis into the search engine and you will find the solution.

marc121 - 10-5-2017 at 15:06

In reality I searched and explored all the subjects but I did not find anything about the conc HN03 90%, that is why I allowed myself to post this request

Praxichys - 10-5-2017 at 16:04

Use a 10-20% molar excess of HNO3 to ensure complete conversion. The amount of sulfuric acid doesn't really matter all that much. It's only acting as the solvent and to help remove water. Start with 1.5:1 molar ratio with the nitric and if it gets too thick, add some more.

[Edited on 11-5-2017 by Praxichys]

marc121 - 10-5-2017 at 16:59

Thanks for the advice, so it's better too HN03 than not enough.
I will do a test
thanks

Praxichys - 10-5-2017 at 17:46

Rereading that I suppose I should clarify the figure to 1.5:1 sulfuric:nitric; add more sulfuric if necessary. Adding excess of either acid will work, but sulfuric is typically cheaper.

[Edited on 11-5-2017 by Praxichys]

marc121 - 11-5-2017 at 03:20

I think I got this, is that it seems correct to you.

HN03 90% 60 Gram
H2SO4 98% 65 grams
PE 99% 10 Gram

HNO3
ACS reagent
Vapor density 1.3 (vs air)
Vapor pressure 6.6 mmHg (20 ° C)
8 mmHg (20 ° C)
Assay ≥90.0%
Dilution test passes test
ign. Residue ≤0.002%
Color colorless to yellow
Bp 120.5 ° C (lit.)
Density 1.48 g / mL at 20 ° C (lit.)

H2S04
0.0001 hPa (20 ° C)
Density 1.84 g / cm 3 (20 ° C)
Mp -20 ° C
PH 0.3 (49 g / l, H₂O, 25 ° C)
Shipped in ambient
Storage temp. Storage temperature: no restrictions.
Specifications Assay (alkalimetric): ≥ 97.5%

thanks

NeonPulse - 11-5-2017 at 13:36

This was the 3rd result in my search
Quote:

Verified efficient method of preparing PETN from diluted HNO3

use
32,7 ml of 70% HNO3 (75% excess)
18,9 ml of 96% H2SO4
10,0 g of Pentaerythrite
------------------------

or
34,0 ml of 65% HNO3 (66% excess)
24,8 ml of 96% H2SO4
10,0 g of Pentaerythrite
------------------------

or
34,8 ml of 58% HNO3 (48% excess)
36,3 ml of 96% H2SO4
10,0 g of Pentaerythrite
------------------------


Nitration:
1. Cool nitration mixture during mixing of acids, thus minimalize even minimal decomposition of HNO3. Nitration mixture must be cooled before nitration process to temperature of 10°C.
2. While stiring, add pentaerythritee in small portions (1-2g) to nitration mixture, always after previous batch is dissolved. Nitration mixture gradually thicken as PETN forming in solution.
3. Constantly monitor reaction temperature and maintain it in 10-15°C range. Interval of adding pentaerytritol conform to reaction temperature, must not rise over 15°C, leave beaker in cold water.
4. Stir with mixture for next 5 minutes after all pentaerythrite is added and dissolved. Mixture is now thick, but stirring is going well. During nitration process must not be developed any brown fumes of NOx!
5. Now put beaker with mixture into water bath and maintain temperature at 50°C, continuously stir with mixture. During 20 minutes at this temperature, all of possible sulfoesters come into PETN for maximal yield of nitration.
6. While maintaining mixture at higher temperature, mixture must be monitored for developing of NOx fumes. Only light brown colour can be in shrouded beaker. Raised development of NOx pointing to higher temperatures used (even during previous nitration) or insufficient chmemicals purity and further heating may end up in uncontrolled reaction and oxidation of formed PETN. In this case it is better to do not heat at all and end just after nitration (if brown fumes apperas during nitration), the yield will be lower. In case of accidentally runaway reaction during heating, immedialtely pour mixture into cold water, don't try stop reaction by cooling beaker, it will not help.
7. When heating after 20 minutes pass off, pour reaction mixture into cold water and follow standart procedure of filtration, neutralization and purifying of PETN.

Yield was 22,1g of PETN from 10g of pentaerythrite, ~95% of theoretical yield (with 65% HNO3 used).

This procedure is result of my research of most effective method preparing PETN from diluted HNO3. Acid ratios are precisely calculated on data from PETN nitration graph published by T. Urbanski in his book vol. IV. Generaly said, PETN is forming to maximum 30% of water portion in nitration mixture. But, when also H2SO4 is contained in nitration mixture, minimum ammount of water must be keep, or oxidation with small yields occur. With this acid ratios 20% of H2O is minimum. So, this nitration mixture has 20% of water on nitration start and 30% at the end, area for most effective nitration, but again only with this ratios. For other acid ratios must be all recalculated. Excess of HNO3 is used to controll ammount of reaction water. Only ammount of nitration mixture can be extended for lower mixture thickness, but it lower utilization of acids and overall efficiency. But it isn't necessary.

I hope there is no major mistakes in my translation to english ;-)

CalAm - 5-6-2017 at 08:19

Quote: Originally posted by marc121  
I think I got this, is that it seems correct to you.

HN03 90% 60 Gram
H2SO4 98% 65 grams
PE 99% 10 Gram

HNO3
ACS reagent
Vapor density 1.3 (vs air)
Vapor pressure 6.6 mmHg (20 ° C)
8 mmHg (20 ° C)
Assay ≥90.0%
Dilution test passes test
ign. Residue ≤0.002%
Color colorless to yellow
Bp 120.5 ° C (lit.)
Density 1.48 g / mL at 20 ° C (lit.)

H2S04
0.0001 hPa (20 ° C)
Density 1.84 g / cm 3 (20 ° C)
Mp -20 ° C
PH 0.3 (49 g / l, H₂O, 25 ° C)
Shipped in ambient
Storage temp. Storage temperature: no restrictions.
Specifications Assay (alkalimetric): ≥ 97.5%

thanks


Are you ordring your acid's from trade india ?

https://www.tradeindia.com/fp3432199/Nitric-Acid-98-.html

Because with the current lot of events playing out in the new's lately it wouldn't seem very smart to be ordering the acid's or PE from online sources in case of interception at mail depots.

Especially when PETN has been used in past events for nefarious deeds. Also wouldn't you dilute your 98% HNO3 to the 70% conc and just use H2SO4 instead of dicking around with WFNA unless you are doing this industrially there is no real advantage.