Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
 Pages:  1  ..  25    27
Author: Subject: nitroglycerin
Bert
Super Administrator
*********




Posts: 2734
Registered: 12-3-2004
Member Is Offline

Mood: " I think we are all going to die. I think that love is an illusion. We are flawed, my darling".

[*] posted on 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.




Rapopart’s Rules for critical commentary:

1. Attempt to re-express your target’s position so clearly, vividly and fairly that your target says: “Thanks, I wish I’d thought of putting it that way.”
2. List any points of agreement (especially if they are not matters of general or widespread agreement).
3. Mention anything you have learned from your target.
4. Only then are you permitted to say so much as a word of rebuttal or criticism.

Anatol Rapoport was a Russian-born American mathematical psychologist (1911-2007).

View user's profile View All Posts By User
ecos
National Hazard
****




Posts: 464
Registered: 6-3-2014
Member Is Offline

Mood: Learning !

[*] posted on 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 !


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.


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 ?
Capture.png - 646kB

[Edited on 25-8-2015 by ecos]
View user's profile View All Posts By User
greenlight
International Hazard
*****




Posts: 684
Registered: 3-11-2014
Member Is Offline

Mood: Energetic

[*] posted on 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]




The only use for an atomic bomb is to keep somebody else from using one.
George Wald
View user's profile View All Posts By User
Bert
Super Administrator
*********




Posts: 2734
Registered: 12-3-2004
Member Is Offline

Mood: " I think we are all going to die. I think that love is an illusion. We are flawed, my darling".

[*] posted on 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.




Rapopart’s Rules for critical commentary:

1. Attempt to re-express your target’s position so clearly, vividly and fairly that your target says: “Thanks, I wish I’d thought of putting it that way.”
2. List any points of agreement (especially if they are not matters of general or widespread agreement).
3. Mention anything you have learned from your target.
4. Only then are you permitted to say so much as a word of rebuttal or criticism.

Anatol Rapoport was a Russian-born American mathematical psychologist (1911-2007).

View user's profile View All Posts By User
Hennig Brand
International Hazard
*****




Posts: 1284
Registered: 7-6-2009
Member Is Offline

Mood: No Mood

[*] posted on 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 411 times


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




"A risk-free world is a very dull world, one from which we are apt to learn little of consequence." -Geerat Vermeij
View user's profile View All Posts By User
ecos
National Hazard
****




Posts: 464
Registered: 6-3-2014
Member Is Offline

Mood: Learning !

[*] posted on 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]
View user's profile View All Posts By User
Bert
Super Administrator
Thread Split
17-9-2015 at 10:07
greenlight
International Hazard
*****




Posts: 684
Registered: 3-11-2014
Member Is Offline

Mood: Energetic

[*] posted on 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.




The only use for an atomic bomb is to keep somebody else from using one.
George Wald
View user's profile View All Posts By User
NeonPulse
National Hazard
****




Posts: 417
Registered: 29-6-2013
Location: The other end of the internet.
Member Is Offline

Mood: Isolated from Reality! For Real this time....

[*] posted on 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.



Where there is a will
there is a way.

AllCheMystery!
https://www.youtube.com/channel/UCWbbidIY4v57uczsl0Fgv7w?vie...
View user's profile View All Posts By User
greenlight
International Hazard
*****




Posts: 684
Registered: 3-11-2014
Member Is Offline

Mood: Energetic

[*] posted on 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.





The only use for an atomic bomb is to keep somebody else from using one.
George Wald
View user's profile View All Posts By User
 Pages:  1  ..  25    27

  Go To Top