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Author: Subject: Pentryl Problems
killswitch
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[*] posted on 29-6-2013 at 11:11
Pentryl Problems


So I used Axt's procedure to form dinitrochlorobenzene and have encountered problems. Instead of a solid, the product appears to be a liquid.

Since Axt's instructions for ridding the dinitrochlorobenzene of spent acid relied on the product being a solid, I had to improvise. I pipetted the liquid (much stickier than crude NG, and yellow-green rather than brown) out of the wash water, diluted it with xylene, and added distilled water. Upon application of magnetic stirring, the aqueous layer immediately turned greenish-yellow.

Since both the mono- and di- nitrated forms of chlorobenzene are solids, I'm wondering just what on earth I'm looking at.

[Edited on 29-6-2013 by killswitch]
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Ral123
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[*] posted on 29-6-2013 at 11:25


I believe the compound you're seeking would have impractically big critical diameter, unless you are seeking the effect of the phosgene give up to kill pests in their holes?
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[*] posted on 29-6-2013 at 12:17


What?

Pentryl:
1. nitrate chlorobenzene to dinitrochlorobenzene.
2. Condense with ethanolamine.
3. Nitrate again to add third C-NO2 group, N-NO2 group, O-NO2 group.

[Edited on 30-6-2013 by killswitch]
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AndersHoveland
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[*] posted on 29-6-2013 at 12:22


You did not use NH4NO3 in the nitration, did you? The ammonium may have condensed, since the nitro groups activate the chlorine group to substitution.

Here, perhaps this procedure will be helpful:
Quote:
90 mL of chlorobenzene is added dropwise with a dropper pipet or buret to a previously prepared, and cooled to room temperature, mixture of 110 mL of 99% nitric acid and 185 mL of 99% sulfuric acid, in a 1000-mL beaker, while the mixture is stirred mechanically with a magnetic stirrer. A stirrer is essential for the length of time required, you may try this by hand with a stirring rod at your own risk. The temperature will rise because of the heat of the reaction, but should not be allowed to go above 50-55 °C. After all the chlorobenzene has been added, the temperature is slowly raised to 95 °C and is kept there for 2 hours longer while the stirring is continued. An upper layer of light yellow liquid solidifies when cold. The layer is removed, broken up under water, and rinsed. The spent acid, on dilution with water, will precipitate an additional quantity of dinitrochlorobenzene. All the product is brought together, washed with cold water, then several times with hot water while it is melted, and once more with cold water under which it is crushed. Finally, it is drained and allowed to dry at room temperature. The product, melting at about 50 °C, consists largely of 2,4-dinitrochlorobenzene, along with a small quantity of the 2,6-dinitro compound, m.p. 87-88 °C. The two substances are equally suitable as precursors for other explosives, or the combined product can be used alone as an explosive. You will need a graduated cylinder for measuring liquids, and a thermometer to monitor the temperature.

Warning: Dinitrochloro benzene is extremely poisonous. Inhaling the vapors can be deadly, as the compound oxidizes hemogoblin in the blood to a form that cannot bind with oxygen, leading to ischemia. Skin contact causes severe rash, itchy burning sensation, and blistering, analogous to poison ivy.


[Edited on 29-6-2013 by AndersHoveland]
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[*] posted on 29-6-2013 at 14:31


So, I have the light yellow liquid mentioned. Do I have to put it in an ice bath to get the solid? There's a ton of tiny yellow-green motes stuck in the goo, and the mass was well below the melting point of DNCB before I added the xylene.

Here's Axt's procedure:

Attachment: pentryl.pdf (416kB)
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[Edited on 29-6-2013 by killswitch]
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[*] posted on 29-6-2013 at 15:45


Perhaps the chlorobenzene you had was contaminated with a large quantity of dichlorobenzene.
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[*] posted on 29-6-2013 at 21:04


It's probably not that. I bought ACS grade chlorobenzene, and a quick check of the scale and volume relates that the density matches monochlorobenzene.

I used 68g NaNO3 instead of 80.9g KNO3, because I had no access to KNO3 at the time. I used a large quantity of sulfuric acid; at least 220ml, to combat solubility issues.

However, after the 2-hour nitration, the NaNO3 had clearly been dissolved long before. Would additional acid have caused problems?
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[*] posted on 30-6-2013 at 18:07


Quote:
You did not use NH4NO3 in the nitration, did you? The ammonium may have condensed, since the nitro groups activate the chlorine group to substitution.


Do you even know what a nucleophile is?




I weep at the sight of flaming acetic anhydride.
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[*] posted on 30-6-2013 at 20:03
AM I GOING INSANE?


So adding concentrated brine caused the organic layer to clarify instantly. I separated them, boiled off most of the xylene and allowed it to cool. But now it's still not solidifying.

When I began boiling it down, a thin cake of solid appeared at the bottom of the beaker. I decanted the solution into another beaker, added distilled water to cover the solid in the first beaker, and warmed it on the hot plate. It melted well below the BP of water, as expected, forming pale green beads. But it's been over twelve motherfucking hours now and it remains liquid (tiny beads, either at the bottom of the beaker or stuck to the top via surface tension). Also, as I continued boiling off the xylene in the second container, no solid was produced even after over a third of its volume was removed, despite the formation of solid occurring almost instantly in the first container. There has been a slight color change (slightly less green, slightly more orange, a little bit darker), but how much is chemical degradation and how much is simply a matter of concentration is unknown.

A bead of unclarified material from the first water crash, adhering to the surface, turned into a clump of solid matter the previous evening, still adhering to the surface until disturbed, promptly sinking to the bottom. This has not happened with the clarified beads.

Seriously, what the fuck is happening?
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[*] posted on 30-6-2013 at 22:21


Quote: Originally posted by madscientist  
Quote:
You did not use NH4NO3 in the nitration, did you? The ammonium may have condensed, since the nitro groups activate the chlorine group to substitution.


Do you even know what a nucleophile is?


To be fair, I missed that too. Got ammonia confused with ammonium. What a difference a proton makes.
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[*] posted on 1-7-2013 at 02:07


However, you don't posture yourself as the resident expert on all things chemistry. Everyone has to start somewhere, but those who pretend to be knowledgeable when they are not are a hazard to others, and not in the way we would consider endearing.



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[*] posted on 1-7-2013 at 05:26


Quote: Originally posted by madscientist  
However, you don't posture yourself as the resident expert on all things chemistry. Everyone has to start somewhere, but those who pretend to be knowledgeable when they are not are a hazard to others, and not in the way we would consider endearing.


Touche. Now with that out of the way, do you have any thoughts on what on earth is happening?

The little beads on the bottom of the beaker of water have somewhat solidified overnight. Tilting the beaker slightly caused extremely thin needles of matter to solidify, and this increase in surface area allowed them to float and adhere to the top. Upon coming into contact with a particularly large bead that had been clinging to the surface overnight with zero noticeable change, said bead began to solidify in a matter of minutes.

No change to the contents of the larger beaker. Still liquid.
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