Sciencemadness Discussion Board - nitroglycerin

nitroglycerin

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ecos - 13-5-2015 at 01:09

I don't like the idea of depending on O2 in air. it might not be enough for complete combustion.

from wikipedia :

Quote:

Tritonal is a mixture of 80% TNT and 20% aluminium powder, used in several types of ordnance such as air-dropped bombs. The aluminium improves the total heat output and hence impulse of the TNT - the length of time during which the blast wave is positive. Tritonal is approximately 18% more powerful than TNT alone.

Wow, 18% increase in power is very good !

is there anyway to calculate the improvement for other EM and the optimum percentage of Al ?

[Edited on 13-5-2015 by ecos]

Hennig Brand - 13-5-2015 at 02:12

You can easily estimate the increase in heat output if you know the percent of Al in the charge and the extent of combustion. The particle size and shape of the aluminum, as well as other factors, will greatly effect the power of the explosive though. I am not an expert on this, so if you dig a little you will likely find more information about how to quantify this.

ecos - 13-5-2015 at 03:35

I started to dig , it seems increasing the percentage of Al above a certain limit will decrease the power.

I found the optimum value for AN is 13% but most people use 10% of Al. in Tritonal they use 20%.

I couldn't find any mixture above 20% Al but no reason why.

ecos - 14-7-2015 at 15:23

Hi All,

I start to wonder, is it possible to make NG gel as a fine powder ? I was thinking that BB can be made fine powder using a ball mill. I was thinking to use the same technique to get a fine powder of NG gel. This would remove the air bubbles inside the gel and make it possible to be used for shaped charges
I found no detonation for NG/NC (91:9) for 2kg from 15 cm as indicated in figure below. this mean the ball mill jar can be smaller in size not to exceed this critical diamater.

Ref : Nitroglycerine and Nitroglycerine Explosives: Phokion Naoum
page : 312

I am just afraid that decrease the size of NG gel would make it very sensitive to shock !.

any suggestions ?

[Edited on 14-7-2015 by ecos]

Metacelsus - 14-7-2015 at 15:47

Would powdering it even work? Would it just get mushed up? Maybe you could freeze it first, like in https://en.wikipedia.org/wiki/Cryogenic_grinding
but less extreme.

Anyway, do this at your own risk. I wouldn't be anywhere nearby.

ecos - 17-7-2015 at 03:15

Quote: Originally posted by Cheddite Cheese

Would powdering it even work? Would it just get mushed up? Maybe you could freeze it first, like in https://en.wikipedia.org/wiki/Cryogenic_grinding
but less extreme.

Anyway, do this at your own risk. I wouldn't be anywhere nearby.

as i understand, NG gel shouldn't be freezed or it would crystallize and be unstable -- thats why they mix NG with Nitroglycol !

ecos - 24-7-2015 at 13:05

short video about Gelatin dynamite : https://youtu.be/n3COSL_cIoc
I was shocked when i saw the process ! i thought NG is more sensitive than being treating like this(picture for the mixer) :

I was very scared when i deal with NG! I read many stories about how danger to handle NG and NC but this video show they are not that sensitive.

I try to avoid making blasting gelatin because i am scared to mix NG with NC and stir them with the thermometer.

any experience how to deal with NG ?

[Edited on 24-7-2015 by ecos]
I also found vidoes for people using syringe to deal with NG ; https://www.youtube.com/watch?v=Qhb3nxS4g84

i thought the pressure of syringe would explode it !

[Edited on 24-7-2015 by ecos]

Hennig Brand - 24-7-2015 at 15:26

Yes, NG under normal conditions is much less sensitive than it is reported to be by many modern sources, however, I am still very careful when handling it. If I am being more careful than needed and wasting a little time and energy it is much better than having an overconfident attitude possibly/likely resulting in a tragic accident that would likely leave me maimed or killed.

It is an interesting video, thanks.

ecos - 24-7-2015 at 16:34

I started to get confused of everything :

Wiki states :

Quote:

Early in its history, it was discovered that liquid nitroglycerin can be "desensitized" by cooling it to about 5 to 10 °C (40 to 50 °F). At this temperature nitroglycerin freezes, contracting upon solidification. Thawing it out can be extremely sensitizing, especially if impurities are present or the warming is too rapid.

In The process of synthesizing NG, it is required an ice path for washing and removing acids i.e, NG would exist in a medium with temperate almost Zero !

for making blasting gelatine , it is preferred to cool NG from 0-5 degres to slow the gelatinization process !

it is also said that any acid traces would be dangerous for NG however, NG is synthesised in acid medium and left for some time!
I feel confused by different sources

[Edited on 25-7-2015 by ecos]

Hennig Brand - 24-7-2015 at 17:03

Wikipedia is not always a reliable reference. It can be a convenient research starting point and the references at the bottom of the Wiki pages are often good.

Frozen NG is very insensitive, but bits of frozen NG in liquid NG can be a very sensitive mixture as can mixtures with bits of sand or other hard gritty substances in a sample of liquid NG for the same reason.

It is much easier to gelatinize NG with NC at slightly elevated temperatures. Not sure about industrial processes, but I have always found the gelatinization process very slow without the help of a solvent and maybe a bit of heat, but then again I was not using the very fine, essentially powdered, NC that is used industrially for the purpose.

Different concentrations of acid effect NG differently, also exposure time makes a difference. I have left spent mixed acids to stand in the dark for one or two days after which I would often obtain as much as 10-15% more NG. I also remember extracting and then only crudely washing a small sample of NG years ago and coming out the next morning to find it boiling and billowing red fumes from the small open beaker holding the sample.

ecos - 25-7-2015 at 09:33

Hi Hennig,

regarding this part :

Quote:

Frozen NG is very insensitive, but bits of frozen NG in liquid NG can be a very sensitive mixture as can mixtures with bits of sand or other hard gritty substances in a sample of liquid NG for the same reason.

I never used distilled water. Also dust can be a factor of things I use ! this mean the NG would be sensitive ?

I was also preparing to add Al powder to NG/NC mixture ! this sounds critical now !

Hennig Brand - 25-7-2015 at 12:26

The sharp edges and corners on hard gritty substances with motion can result in localized high pressure and heat being generated between these surfaces and each other or other surfaces which can sometimes be enough to result in initiation.

Not all dust is the same though. I couldn't say for sure how much of a sensitizer your particular type of dust is. I just try to avoid any contaminants, but especially hard gritty contaminants. NG/NC mixtures are normally very insensitive and mixing in fine flake aluminum should be fine.

https://www.tedpella.com/company_html/hardness.htm

Mohs Scale

Hardness of Quartz (Vitreous Silica): 7
Hardness of Aluminum: 2-2.9

ecos - 25-7-2015 at 17:10

Quote: Originally posted by Hennig Brand

Wikipedia is not always a reliable reference. It can be a convenient research starting point and the references at the bottom of the Wiki pages are often good.

Frozen NG is very insensitive, but bits of frozen NG in liquid NG can be a very sensitive mixture as can mixtures with bits of sand or other hard gritty substances in a sample of liquid NG for the same reason.

It is much easier to gelatinize NG with NC at slightly elevated temperatures. Not sure about industrial processes, but I have always found the gelatinization process very slow without the help of a solvent and maybe a bit of heat, but then again I was not using the very fine, essentially powdered, NC that is used industrially for the purpose.

Different concentrations of acid effect NG differently, also exposure time makes a difference. I have left spent mixed acids to stand in the dark for one or two days after which I would often obtain as much as 10-15% more NG. I also remember extracting and then only crudely washing a small sample of NG years ago and coming out the next morning to find it boiling and billowing red fumes from the small open beaker holding the sample.

I think you mean frozen NG is sensitive !
I was reading today more about NG since it is the only HE I can prepare now:

book name : high explosives and propellants
Author ; S. Fordham
page 38

Bert - 25-7-2015 at 21:52

Quote:

I think you mean frozen NG is sensitive !

No, he meant exactly what he said.

Frozen NG is quite INsensitive. Partially frozen NG is bad news... Incautious attempts to thaw NG or NG explosives not formulated for cold weather use are also a historically famous source of accidental explosions.

Too tired to dig out the references right now. Google George Mowbray, Hoosac tunnel, sleigh, frozen NG.

Praxichys - 26-7-2015 at 05:28

Quote: Originally posted by Bert

Frozen NG is quite INsensitive. Partially frozen NG is bad news... Incautious attempts to thaw NG or NG explosives not formulated for cold weather use are also a historically famous source of accidental explosions.

Yes, I believe this to be correct. Think of the higher polyols. ETN is more sensitive when melted than frozen. NG should be the same way.

IIRC the reason frozen NG is more dangerous is that attempts to thaw the NG before electric heating was available lead to many accidents. Frozen NG in handling equipment sometimes lead unknowledgeable operators to force equipment or warm it over a fire. I can find no account of thawing NG actually exploding by itself other than in internet heresay. It doesn't make sense from a chemical standpoint anyway.

http://www.logwell.com/tales/frozen_nitroglycerin.html

EDIT: Whoops, wrong argument.

[Edited on 26-7-2015 by Praxichys]

Tabun - 26-7-2015 at 10:26

Quote: Originally posted by ecos

short video about Gelatin dynamite : https://youtu.be/n3COSL_cIoc
I was shocked when i saw the process ! i thought NG is more sensitive than being treating like this(picture for the mixer) :

I was very scared when i deal with NG! I read many stories about how danger to handle NG and NC but this video show they are not that sensitive.

I try to avoid making blasting gelatin because i am scared to mix NG with NC and stir them with the thermometer.

any experience how to deal with NG ?

[Edited on 24-7-2015 by ecos]
I also found vidoes for people using syringe to deal with NG ; https://www.youtube.com/watch?v=Qhb3nxS4g84

i thought the pressure of syringe would explode it !

[Edited on 24-7-2015 by ecos]

I was also a little scared...never worked with it but I thought it's more sensitive.I first heared about its true sensitivity from Uncle Fester's book.After that I looked into it a little more and learned about it but I still thought it's easy to initiate as I said in this topic.I now know how it trully is after reading Urbanski's book on the subject and another book which you can find in the library(sciencemadness's library).Now it's really annoying to see people trying to convince you how unstable it is and other s**ts like this...

Praxichys - 27-7-2015 at 05:54

I remember my first experiences with NG. Having just sworn off peroxides (mostly MEKP), I made some NG which I had read was much more powerful. I was very nervous the first time and I used all the same plastic labware I had used to make organic peroxides, shaking slightly, with a sweat band (yes, I am a product of the late 80s) controlling the salt water over my eyes.

Initially my 16 or 17-year-old self thought I had botched the synthesis, since I was unable to detonate any by hammer blow using my standard benchtop-vise/anvil and the 6oz ball-peen hammer which could set off MEKP easily with a stern tap.

It still burned like the devil though, hissing away in a pale white flame - I knew something was amiss. Fetching large piece of steel stock and my dad's biggest framing hammer, I gave it several good overhand strikes before it let loose like a 12-gauge. I felt the thump in the chest and all the ducts and pipes in the basement sang for a full second, loose sawdust from the shop snowing from the ceiling under the glare of the fluorescent lamps.

The sense of accomplishment was palpable among the particles of sawdust. If my youth ever had halcyon days, that was one of them.

Anyway, I learned to respect NG but also that its sensitivity makes it rather benign to work with in a laboratory, with due care. Indeed the stuff is dangerous in an industrial setting when tens of liters of the stuff is thrown around in buckets, trounced by machines, and spat from noodle plates under the care of an army of 19th-century laymen. However, for the occasional laboratory curiosity, a healthy respect for explosives does well to remove undue hazard.

[Edited on 27-7-2015 by Praxichys]

ecos - 27-7-2015 at 09:06

A lot of stories gave me and indication that NG is more sensitive than AP.

I have a big interest in NG since glycerin is cheap ,available everywhere and can produce HE when nitrated.

NG gelatine can also be used as propellent and this interest me a lot (double base propellent).

The detonation power of NG and its mixtures is variable. it vary from 2000 to 8000 m/s , please check figure below :

I think no one would like to spend effort in synthesizing NG and then get VoD that reaches 2000 ms !

one of the solutions that proposed to achieve the high VoD for NG gelatine is to use special initiators as expressed in US2525397

the initiator in patent above depend on PETN and special casing design of the detonator ! I didn't like the idea coz i don't have Pentaerythritol and I am not going to press EM that much to achieve certain density.

I found in a reference this statement :

Now, I need to insert high density material in NG gelatine to reach the max VoD , Al has density of 2.7 g/cm³ !
I have MnO2(Density: 5.03 g/cm³) and Fe2O3 (Density: 5.24 g/cm³) but Hennig remarked before that even sand can cause problem so think about metals ! I feel that I am going to increase the sensitivity of NG a lot with this idea !

the book didn't even mention the quantity I need to add !

do any body have any valuable idea ?

[Edited on 27-7-2015 by ecos]

[Edited on 27-7-2015 by ecos]

kecskesajt - 27-7-2015 at 10:11

Maybe other exlplosive powders like PETN or HMX or even TNT.What about diatomaceus earth?That way used in the first dynamites.Or wood dust.
Al makes ETN much more sensitive.

[Edited on 27-7-2015 by kecskesajt]

Tabun - 28-7-2015 at 04:05

Quote: Originally posted by ecos

the initiator in patent above depend on PETN and special casing design of the detonator !

[Edited on 27-7-2015 by ecos]

The only special thing I have seen in that patent is the thickness of the blasting cap's bottom.And it doesn't only mention PETN.If PETN would work,why wouldn't ETN?

Does anybody have any experience with Nitroglycide and gelatine made with this?

Bert - 28-7-2015 at 06:39

Or you could just use a thin gelatin (ca 2-3% NC) and make a 60% NG ammonium nitrate/wood flour based gelignite. THAT will not likely fire at the low velocity quoted.

I long ago fired a small sample of 2% NC jelly soaked 200 mesh granular magnalium, ratio about 40% jelly to 60% 50:50 Mg/Al powder. Bled jelly if allowed to sit, had to pack in plastic film. It worked very well in a .75" Dia. charge, producing a flat, high pitched CRACK! similar in tone to a heavy PETN det cord- but I did not bother to determine the velocity. Flash of light it gave was AMAZING.

[Edited on 28-7-2015 by Bert]

ecos - 28-7-2015 at 07:49

@kecskesajt , all what you stated has low density and the concept is not to add absorbent like diatomaceus earth
adding PETN , TNT ,... would be a very expensive solution ! adding Metal to increase the density would be a better solution.

I am not sure if adding metal powder (Fe2O3 or MnO3) would add a lot of hazard to the NG gelatine or not ! I am not expert with NG mixtures.

@Tabun, he mentioned to press it well to reach a high density initiator, I think ETN will work but I didnt like the patent concept !

@Bert, here is what i found for AN mixtures with NG :

The maximum power would reach 85% of blasting gelatine , this means lower VoD and it might not work for shaped charges !

I found some mixtures stated in US4764229

I made hard search for compositions and I found this mixture from the patent above:

It is also noted the power has 80% strength even after adding Al powder

! unfortunately, The author didn't provide any info about VoD and I am stuck to calculate it myself.

[Edited on 28-7-2015 by ecos]

[Edited on 28-7-2015 by ecos]

PHILOU Zrealone - 28-7-2015 at 11:41

The sensitivity of NG when frozen comes also from tiny bubbles entrapped into the matrix, generating hot spots when shocked by a compression wave.

Tawing usually generate a risk of local overheating and hence deflagration and detonation.

Same effect is seen with microballoons and low density NH4NO3 for sensitivity increase.

[Edited on 28-7-2015 by PHILOU Zrealone]

ecos - 2-8-2015 at 04:05

Quote: Originally posted by Bert

Or you could just use a thin gelatin (ca 2-3% NC) and make a 60% NG ammonium nitrate/wood flour based gelignite. THAT will not likely fire at the low velocity quoted.

I made some searches in Naoum book and found that any mixture has NG as ingredient will suffer the same problem of low VoD :

and

even storage will affect the sensitivity and very strong cap would be needed to get the max VoD. (cap8)

it seems detonation of NG is not an easy thing :

[Edited on 3-8-2015 by ecos]

Regeneration of sulfuric acid nitrating mixtures (after synthesis nitroglycerin)

ecos - 14-8-2015 at 07:09

Very interesting video about Regeneration of sulfuric acid nitrating mixtures (after synthesis nitroglycerin)

https://www.youtube.com/watch?v=DASQdQMwaB4

Hennig Brand - 14-8-2015 at 10:15

Seems kind of dangerous and an awful waste as well. Rather than waste all that nitric acid why not use most of it to nitrate an aromatic compound, like is described here:

http://www.sciencemadness.org/talk/viewthread.php?tid=19861

The sulfuric acid could be much more easily and safely recovered afterwards.

The experimenter in the video probably could have made a fair bit of sodium or potassium nitrite if he or she had bubbled the nitrogen oxides through a solution of either sodium carbonate or hydroxide or potassium carbonate or hydroxide.

http://www.sciencemadness.org/talk/viewthread.php?tid=439&am...

I would personally use the first method and nitrate an aromatic compound to soak up most of the nitric acid before purifying and concentrating the sulfuric acid.

[Edited on 15-8-2015 by Hennig Brand]

ecos - 14-8-2015 at 12:34

Any traces on NG in the acid would make a big problem !

I read more about NG synthesis and i found two strange points :
1- sometimes they use air to flush NG

2- they use coffee filters to remove any impurities

I didnt find both steps in my books. any idea?

both steps were under filtration of NG : https://www.youtube.com/watch?v=Jz5jx2LrZ2Q

[Edited on 14-8-2015 by ecos]

NeonPulse - 15-8-2015 at 04:47

Using the air bubbler is to neutrallize the NG properly and takes far less time to do than simply rolling the NG around in the beaker. I have used both methods and the bubbler is much better and took about 1/3 less time to do plus you can leave it to do its thing remotely and thus safely. not sure about filtering it though. I cant see what would need filtering out of the NG if it is made properly.

On regeneration: couldn't you extract all of the last traces of the NG with chloroform and then regenerate the mixture more safely?(not that i'd ever try this) i would be much more inclined to just get rid of it and start again for safety sake

ecos - 15-8-2015 at 16:32

I neutralize NG using sodium bicarbonate.... so what is the difference between sodium bicarbonate and air bubbling ?

greenlight - 15-8-2015 at 20:15

Air bubbling is bubbling air through NG in a solution of sodium bicarbonate with a pump. This agitates the NG, exposing more surface area to the basic solution neutralizing residual acid faster and more effectively.

ecos - 16-8-2015 at 02:45

ahaa. so stirring is not as efficient as bubbling air ?

PHILOU Zrealone - 16-8-2015 at 03:54

Quote: Originally posted by ecos

ahaa. so stirring is not as efficient as bubbling air ?

Above a certain speed stirring is dangerous with NG... because the NG could be squeezed between two hard surfaces (recipient wall and agitator)... or you could get cavitation bubbles and shock behind the blade. Cavitation bubbles reach very high inner pressure and temperature; that is why ultrasonication is not an option here...

Bubbler is fine as a mixing way but the recipient shape must be addapted of course...
The risk of hard shock between a bubble and the recipient wall is 0! The only risk is more NG vapour in the air...

greenlight - 16-8-2015 at 03:58

Yes, what PHILOU said, squeezing between the stir rod or (stir bar which would be even worse) and glass vessel wall could be a bad time

.

If you bubble air it would be much more effective plus you can turn the pump on and stay away just in case instead of sitting over the beaker stirring.

[Edited on 16-8-2015 by greenlight]

ecos - 16-8-2015 at 07:31

It is very good to take the best safety precautions when dealing with EM.

Almost 99% of all NG synthesis videos over internet uses magnetic stirrer. Almost all patents I read used magnetic stirrer as well !.

greenlight - 16-8-2015 at 08:00

100% correct. Minimize risk as much as possible = more chance of keeping your life/fingers/hands.

Magnetic stirrer would have to be a no. A stir bar spinning at any speed is creating friction and rubbing on the bottom of the glass vessel.
I have seen a couple of nitroglycerine synthesis clips on the net with people stirring to wash the NG very fast with a thermometer even banging the sides a couple of times.
Even though nothing happens the 100th doing time doing it that way, it could detonate on the 101st.

ecos - 16-8-2015 at 09:47

Hennig posted those photos for new setup to decrease the risk : http://www.sciencemadness.org/talk/viewthread.php?tid=949&am...

for lab :

NG is very sensitive to viberation , I recall it would be 200 Hz for detonation for NG.

even this setup would be risky for high speed rotation , is my understanding correct ?

[Edited on 16-8-2015 by ecos]

greenlight - 16-8-2015 at 10:10

That is quite a nice stir setup he has made.
I think it would be very safe as it is a battery drill so not much vibration at all and I don't think it would be operating full speed. Friction would be the main enemy.
Drills vibrate more when they are drilling into something and there is resistance. With stirring a liquid there is hardly any and the stir-paddle is quite small.
No chance of the paddle hitting the side of the flask either as long as the drill is well secured, you could position a thermometer in a clamp just above the paddle and stir away when nitrating as well.

The actual lab overhead stirrer made for chem work looks interesting as well especially if it came with an acid resistant PTFE stir paddle. Probably quite expensive though.

[Edited on 16-8-2015 by greenlight]

Hennig Brand - 16-8-2015 at 12:43

Thanks, just to refresh, at the low temperatures and acid concentrations of a nitric esterification 304 and 316 stainless steel stirring rods will hold up well (corrosion is extremely slow). There are higher performance, more involved designs, but as far as stirrer paddles go even a relatively simple, large, slow moving paddle seems to do the job well, at least on the small scale. As well as having good chemical resistance PTFE and HDPE are both very low friction materials, and are very often used in applications where this property is important. Also, as was stated, as long as the stirrer paddle is positioned correctly and secure, and the vessel is secured, there is little chance of the paddle contacting the sides of the vessel anyway.

ecos - 16-8-2015 at 13:16

I believe that magnetic stirrer is not the best option , Hennig stirrer would be a better solution.
the speed of stirring should be a factor in setup. Very high speed would add high risk to the nitration process.

As i stated, NG would detonate at 200 Hz vibration.
I would think the motor speed should not exceed 100 RPM to be in safe side. (just thoughts)

ecos - 20-8-2015 at 01:51

Just an interesting photo :

7 Biazzi fully automated nitration plant (nitroglycerine), 1956, the world's largest Biazzi plant.

it is very interesting the amount they nitrate

[Edited on 20-8-2015 by ecos]

greenlight - 20-8-2015 at 02:16

I think they would have very strict temperature control with alarms if it went too high and a paddle stirrer inside. That is a large NG reaction vessel thats for sure!
If too much of a temp climb happens (runaway) they can drown the reaction mix into a large vat of water below by pushing a button I have read.

[Edited on 20-8-2015 by greenlight]

greenlight - 20-8-2015 at 03:38

Here's another interesting photo before of an early nitroglycerin manufacturing plant.
Nitrator's had to sit on a one legged stool so they paid attention and did not daydream/fall asleep while watching the temperature during the process.

[Edited on 20-8-2015 by greenlight]

kecskesajt - 20-8-2015 at 03:54

For purification:Why not dissolve NG into acetone and then add this to NaHCO3 solution?Or directly add NaHCO3 to the NG/Acetone?And then remove the salt with water wash?

ecos - 20-8-2015 at 04:07

The interesting thing here is the temperature control system and the valves !

Many posts on the internet warn from using a separation funnel since the stopcock can be a source of hazard.

valves can cause a disaster specially with NG , is there any special designs for such valves?

greenlight - 20-8-2015 at 04:59

I think the valves are for the inflow of sulphuric, nitric and glycerin and air and water in and out for the cooling jacket. Some of them could also be vents for pressure and fume release.

I think the reaction mixture is led from the main vessel to a floor below where it is skimmed off from the mixed acids with a special tool as is stated on this page (quite an interesting article):

http://lateralscience.blogspot.com.au/2014/10/scottish-nitro...

[Edited on 20-8-2015 by greenlight]

[Edited on 20-8-2015 by greenlight]

Bert - 20-8-2015 at 06:14

Quote: Originally posted by ecos

The interesting thing here is the temperature control system and the valves !

Many posts on the internet warn from using a separation funnel since the stopcock can be a source of hazard.

valves can cause a disaster specially with NG , is there any special designs for such valves?

You don't need a valve- Merely a rubber or acid safe plastic hose attached to bottom of reaction or washing vessels. Other end of hose is held up above level of liquid in vessel until vessel is to be drained, then worker lowers end of hose to allow liquid to drain from bottom of vessel. Same hose can be used to introduce air for agitation of NG and wash waters if vessel is small and no mechanical stirrer is wanted-

PHILOU Zrealone - 20-8-2015 at 08:39

Quote: Originally posted by kecskesajt

For purification:Why not dissolve NG into acetone and then add this to NaHCO3 solution?Or directly add NaHCO3 to the NG/Acetone?And then remove the salt with water wash?

If your NG is well cleaned, no problem;
otherwise
--> Have you ever put aceton in contact with HNO3 or with H2SO4?

1°)The first one goes runaway NxOy cloud in less than a minute.

2°)The second induces exothermic condensation and crotonisation into mesityl oxyde, phorone, mesitylen, ...
(CH3)2C=O + CH3-CO-CH3 --> (CH3)2C=CH-CO-CH3 + H2O
(CH3)2C=CH-CO-CH3 + O=C(CH3)2 --> (CH3)2C=CH-CO-CH=C(CH3)2 + H2O
3 (CH3)2C=O --> cyclo(-C(CH3)=CH-)3 + 3 H2O

[Edited on 20-8-2015 by PHILOU Zrealone]

kecskesajt - 20-8-2015 at 09:46

Thanks,PHILOU, I never thinked about it.

ecos - 21-8-2015 at 01:19

Quote: Originally posted by Bert

Quote: Originally posted by ecos

Hi Bert,

I am already aware of this technique , I also saw it in the video : https://youtu.be/n3COSL_cIoc?t=5m34s

They also used something to stop the flow but it doesn't cut it completely.

In automated systems the use of valves would be logical to avoid any human mistakes !

[Edited on 21-8-2015 by ecos]

ecos - 22-8-2015 at 11:53

did you see someone shaking NG ?! I did :

watch from here : https://youtu.be/LMU9JAK0Hik?t=2m59s

crazy people !

[Edited on 22-8-2015 by ecos]

Bert - 25-8-2015 at 06:26

Quote:

did you see someone shaking NG ?! I did :

watch from here : https://youtu.be/LMU9JAK0Hik?t=2m59s

crazy people !

Shaking NG in wash water is done by some. Swirling the NG in a stoppered flask with a basic wash water until the NG is broken up into droplets, then shaking it fairly hard to break up the droplets still further and speed the washing process did not kill me as a teenaged experimenter.

Wet NG suspended in wash water is not very sensitive. As an emulsion in water, it has been pumped between various operations in industrial production- That way, transport pipes don't propagate explosion between buildings.

If NG really behaved like I₃N, it would not have been (and still be!) an industrial chemical routinely made and handled by the ton.

Even after separating from the final wash water, residual water needs to be dried from the NG before one can do sensitivity tests and get a true idea of how sensitive dry, pure NG can be. Hammering a small drop of damp NG fresh from the washing operation on a scrap of filter paper (steel hammer on steel anvil) often failed to get so much as a pop- Once dried, a good tap made my ears ring.

ecos - 25-8-2015 at 07:08

Quote: Originally posted by Bert

Quote:

did you see someone shaking NG ?! I did :

watch from here : https://youtu.be/LMU9JAK0Hik?t=2m59s

crazy people !

what is I3N ?

since you mentioned "drying NG".
I found a video that uses AN for drying NG. it is a cool idea since it depends on the Hygroscopic effect of AN.
do you think it is effective in drying ?

[Edited on 25-8-2015 by ecos]

greenlight - 25-8-2015 at 07:44

He means nitrogen triiodide, sensitive touch explosive.

The photo you uploaded is a makeshift desiccation jar (desiccator).
You can probably use other compounds as the desiccant like anhydrous calcium chloride or concentrated sulfuric acid in them if you wanted as well.
I don't know how effective it would be if with drying a liquid as I have only ever used that method to dry solids.

[Edited on 25-8-2015 by greenlight]

Bert - 25-8-2015 at 08:37

Water is less dense than NG, and merely leaving the NG out in atmosphere on a low humidity day, in an open container with a wide surface area relative to depth was sufficient to dry it within a day, as far as I can recall. But I never made very much, a porcelain "ramekin" less than 100ml capacity served to dry 20-30ml of NG, and also to hold it for subsequent processing- Such as gelatinizing with NC, gently warming on a water bath and addition of any dynamite making "dope".

I might choose a Polyethylene container instead, these days. Just in case of an issue?

Using a dessicator would probably be faster, but I never bothered. It would be helpful in a humid climate, and even required for careful analytical work.

Hennig Brand - 26-8-2015 at 06:50

From Wiki:

"
For molecules of a liquid to evaporate, they must be located near the surface, they have to be moving in the proper direction, and have sufficient kinetic energy to overcome liquid-phase intermolecular forces. When only a small proportion of the molecules meet these criteria, the rate of evaporation is low. Since the kinetic energy of a molecule is proportional to its temperature, evaporation proceeds more quickly at higher temperatures. As the faster-moving molecules escape, the remaining molecules have lower average kinetic energy, and the temperature of the liquid decreases. This phenomenon is also called evaporative cooling. This is why evaporating sweat cools the human body. Evaporation also tends to proceed more quickly with higher flow rates between the gaseous and liquid phase and in liquids with higher vapor pressure. For example, laundry on a clothes line will dry (by evaporation) more rapidly on a windy day than on a still day. Three key parts to evaporation are heat, atmospheric pressure (determines the percent humidity) and air movement."

The following vapor pressure data for NG came from the attached document:

Vapor pressure of NG at 20C:
0.00012 - 0.011 mmHg

Vapor pressure of water at 20C:
17.54 mmHg

IIRC, density is the key factor when separating things like saturated hydrocarbons and the intermolecular forces in the liquid phase are fairly constant from one species to the next and obey the idealized laws very closely. For many other liquids, though, the intermolecular forces in the liquid phase are of much greater significance and much less consistent with the idealized laws. I suppose we should also consider the intermolecular forces between the water and the NG, not just the water and NG separately, but simply looking at the extremely low solubility of NG in water tells us that these forces are very small in comparison and of little concern.

I have left beakers sit out with NG sitting in them, in a safe location undisturbed, for days with very little loss of NG. It is so easy to dry NG by simply leaving it sit out for a day or so that I never bothered doing anything else once I learned this.

Regarding sensitivity of NG, temperature is very significant. I remember that on a cool day in the fall, between 15-20C, it would take a very hard smack with a hammer on steel to effect detonation, however, on a hot 30C day even a fairly gentle snap from a small hammer could easily result in detonation.

I just found the following information sheet on NG and EGDN online. It has vapor pressure information as well as other key values for both nitric esters. The sheet also has a lot of occupational health and safety information, which is actually the main focus of the document.

Attachment: Nitroglycerin & Ethylene Glycol Dinitrate Information Sheet.pdf (324kB)
This file has been downloaded 642 times

[Edited on 27-8-2015 by Hennig Brand]

ecos - 27-8-2015 at 04:34

Thanks Hennig and Bert, The information you provided are really valuable.

It scares me when I leave NG to dry for a day or several days. I am just afraid that impurities would make it acidify. I remember that molecules would break down to Glycerol and HNO3 because of impurities or other stuff I don't remember. This means risk is increasing by time.

It is a common rule not to leave NG dry and always dissolve it in Acetone or underwater with small bicarbonate ratio.

I found this way in a document :

Quote:

The resulting emulsion was transferred to a separatory funnel and extracted four times With 25 mL methylene chloride. The combined organic extracts Were dried With MgSO4 and then concentrated to produce NG as a clear pale yellow liquid

The author used separation funnel to remove as excess water. but I don't understand what he would do with methylene chloride or MgSO4 !

unfortunately the stopcock can cause hazards !

I was thinking of two solution:
1- make air path that dry NG faster, This can be achieved using a small fan inside a PVC tube.
2- use AN as desiccator. AN should act as magnet to water in NG. This would make NG wet and cold. AN can be dried later under lamp. but since AN is colder won't that make the evaporation slower ?

[Edited on 27-8-2015 by ecos]

[Edited on 27-8-2015 by ecos]

greenlight - 5-12-2015 at 21:01

Just curious as to what your guys opinions are on whether it is dangerous to use a seperatory funnel to seperate the NG from the aqueous phase during extraction and washing.

NeonPulse - 6-12-2015 at 04:48

This is done pretty frequently in small lab scale preparations and as long as the stopcock is Teflon and very well greased there should be no problems. This is how I do this. It is probably the easiest and no fuss way to separate your Ng from the spent acids/wash waters.

greenlight - 6-12-2015 at 06:22

I have used my small sep funnel with a well greased glass stopcock when doing small batches but was quite worried while doing it.

Would a better option be decanting until the final separation and then using a well greased funnel and doing so in small portions.

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