Johnny Windchimes
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My Synthesis of Nitroethane via a AgNO2 Packed Column
Good day all,
It's bean rather exhaustively discussed on these boards and elsewhere for the better part of 25 years, and the consensus seems to be that it's a pain
to make. That's because it is a pain to make.
Chemplayer's great video was still unfortunately a ton of setup and time for a relatively small yield. Silver being part of this reaction complicates
it further from a monetary point of view as well.
I have recreated Chemplayer's Victor-Meyer style synthesis using anhydrous THF in lieu of Ether, and Bromoethane in lieu of Iodoethane, with similar
(albeit worse) results.
Those who have read the literature know of course about the industrial methods using propane and ethane at 400 C and vapourized nitric acid etc etc;
these industrial processes are best left alone. KABOOM comes to mind when I even think of trying one on a lab bench scale.
(As an aside, I did find one nitration of ethane that runs at 100 C, using UV light as the catalyst, paper attached below)
----------------------------------------
Now, radiochemistry is not really something done in a home chemistry setting, which is why this method and it's paper might have slipped through the
cracks a bit:
https://www.thevespiary.org/rhodium/Rhodium/Vespiary/talk/in...
About half way down the page there is a post by "no1uno" detailing an interesting method. I gave it a try, results below:
A jacketed Liebig condenser was lightly packed with a 90/10 AgNO2/Silica sand mix and a glass wool plug was inserted in the bottom. A glass takeoff
adapter with a long glass hollow rod was led into Distilled H2O. About 1 Mole of AgNO2 was used (+/- 10% to make sure the Liebig was topped off)
A 1000 ml RBF was charged with 6 moles of Bromoethane (freezer stored, synthesized 1 year ago, dried using 3 Angstrom Molecular Sieves). A stir bar
was inserted and the flask placed in a heating mantle. One neck of the flask was then connected with a 3 way distillation adapter, and the AgNO2
packed Liebig was connected to this adapter giving it a slight downward angle which helped facilitate product collection (IMO).
I did not use an N2 or a CO2 stream of dried carrier gas as per the paper. I settled on a 24/29 12 inch 3.3 boro tube packed with CaCl2 and a small
aquarium style air pump to bubble dried room temp air into the Bromoethane as it was being heated and help push it into the AgNO2 packed Liebig.
The AgNO2 packed Liebig had its jacket connected to a small pressure cooker that was delivering steam to the jacket to keep it at approximately 100
Degrees C for the entirety of the run. A Jacketed HPLC column would have been even more ideal however I do not own a jacketed one and the Liebig
seemed a good compromise.
Steam was introduced to the AgNO2 packed Liebig, and the heating mantle was turned on. Bromoethanes boiling point is 38.4 C, so not much heat was
required to vapourize it. The air pump was turned on (very light flow, basically enough to keep positive pressure and encourage the Bromoethane to
flow into the AgNO2 packed Liebig).
About 1.5 hours were required to send a majority (approx 25 ml left in the distilling flask) of the Bromoethane through the AgNO2 packed Liebig, and
the dried air positive pressure flow helped to push the effluent reaction mix down into the Distilled H2O. I used a conical 1000 ml flask with a take
off side arm as the receiving flask, and then ran the take off into another 1000 ml conical flask just to ensure I captured as much as possible. The
paper uses DMSO to capture the nitroalkanes, but I am all out of DMSO currently.
The pressure cooker, mantle and air pump were turned off and the entire setup was allowed to come back to room temperature.
The Distilled H2O receiving flask (Just the first one in the train) had 2 semi-opaque layers. This was put into a sep funnel, and the top aqueous
layer retained and extracted with 50 ml of DCM once.
The organic layer was pooled with the DCM extraction, and dried over CaCl2 for several hours in the fridge. The flask was rigged for fractional
distillation on a hotplate with stir bar added.
The Bromoethane came off intermixed with the DCM (their boiling points are basically the same). I chose DCM because I would rather contaminate my
cheap and easily made Bromoethane than face a toluene azeotrope / pure toluene boiling point(s) of 80/110 C respectively, the latter which would
definitely co-mingle with any Nitroethane coming off at circa 114 C. In hindsight I would not have pooled my DCM extract with my main organic layer
and worked it up separately.
After removing approximately 350 ml of seemingly unreacted Bromoethane and DCM (very volatile so no doubt mechanical losses as well as evaporative
losses as well throughout the process) through fractional distillation, the temperature climbed past 110 C and around 112 C a slightly yellow oily
liquid came over.
The collection flask was changed out and approx 10 ml of what was assumed to be Nitroethane was collected. Its characteristic smell was compared to a
known authentic sample (briefly, as its..... you know.... toxic.....).
This yield is a very poor 14% based on starting silver nitrite, with a 6 x molar excess of Bromoethane thrown in to boot.
HOWEVER, given the cost of Bromoethane and the ease of this solvent-free setup, I feel that if I tweak this procedure to be more in line with the
paper, coupled with all the potentially unreacted Bromoethane recovered during workup, we could have a very viable source of Nitroethane!
The next time I run this experiment I will take and post photos of the entire thing. Questions and comments are welcome!
Sources:
Attachment: 1017-Online.Synthesis.11C.Nitroalkanes0474 - Copy.pdf (131kB)
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Attachment: EP83107806NWA1 - Copy.pdf (351kB)
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[Edited on 16-4-2020 by Johnny Windchimes]
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monolithic
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It's nice to see someone posting results. Everyone talks about nitroethane syntheses but no one ever posts results. 
Have you ever tried the bromoethane and sodium nitrite in DMSO reaction? https://www.hyperlab.info/inv/index.php?s=61ad7dd3930f684e12... (Run it through Google translate.) I plan on running this in the coming months.
I've heard a lot of people fail miserably with this reaction but then there are a few -- not many -- posts which show it works quite well for how
cheap the reagents are. This reaction is all based on the work of Kornblum, see the following links:
DOI: 10.1021/ja01588a059
DOI: 10.1021/jo01355a612
DOI: 10.1039/B805985C
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chemplayer...
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Very interesting write-up and well done for going to the lengths to try this out! It shows that the reaction with bromoethane can work, but it's much
slower and needs more stringent conditions to get to work.
Problem still in the end really is the cost of the silver salt - we played around recovering the metallic silver but it's trickier than you'd think
and gives you ~75% return if I remember. The iodine can also be recovered to some extent and recycled, but iodine is getting more and more expensive
too (but not quite silver levels).
The holy grail is finding the conditions or OTC solvent that can do this with sodium nitrite. We wondered if acetonitrile might work, but never got
the time to try it out.
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Johnny Windchimes
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Quote: Originally posted by chemplayer...  |
The holy grail is finding the conditions or OTC solvent that can do this with sodium nitrite. We wondered if acetonitrile might work, but never got
the time to try it out. |
Forgive me if I blush, but I'm a huge fan! I cant believe I'm even passively chatting with you! You guys rock! I've watched every single video of
yours (most looped on repeat because I'm insane like that!).
Ok school girl giggles aside, I do intend to play with this one a bit more, but I'm also wondering if maybe this is our long sought 'Holy Grail'?
Source attached down below!
PEG-400 is not quite hardware store shelf, but 1000 places sell it for mixing with vaping fluid these days, as well as of course eBay and Amazon.
I've included their 2004 paper on a x 4 molar AgNO2 excess aqueous Alkyl Halide Nitroalkane synthesis as well for context, it was known on the hive
and such places if I recall, but their 2008 follow up paper would be the one I'm intrigued to give a go. I've ordered a liter of PEG-400 from a vape
shop online this very day!
I'll post follow ups when I finish experimenting!
***EDIT*** Their PDF that goes along with their 2004 paper now also attached.
Attachment: ballini2004 - Copy.pdf (46kB)
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Attachment: ballini2008 (Grail) - Copy.pdf (87kB)
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[Edited on 18-4-2020 by Johnny Windchimes]
Attachment: 2004 add-on ballini pdf - Copy.pdf (975kB)
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Johnny Windchimes
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Two steps forward.....
Although it might be going in the wrong direction insofar as OTC goes....
These two papers use Polymer suspended nitrite to get the job done. This is prepared from Sodium Nitrite as opposed to the pricey Silver Nitrite as
well.
I have nothing against Iranian chemistry, or the Journal of The Chinese Chemical Society per se (re: Zarchi 2005), but it seems in line with Gelbard
1977 in relation to the theory at least. The polymer Zarchi use's is a tad more exotic, but I found it easily on Alibaba once typing in the CAS
number. Some people I've noticed don't trust out of the way journals or chemistry at face value, for perhaps good reason.... but it looks legit (in my
infinite wisdom haha).
Worth mentioning is Zarchi also in his paper directly synthesizes Nitroethane (among other Nitroalkanes) as opposed to everyone else who makes longer
chain Nitroalkanes and only allude to their methods short chain Nitroalkane application(s).
And I'll throw in Ballini & Palmieri's 2018 Nitroalkane Review paper too for kicks. It's nice to know these boys are dedicated over the years....
If the PEG-400 Synthesis fails I'll give the polymer ones a try as well. I'm kinda addicted to finding a reasonably working method at this point!
Attachment: zarchi2005 - Copy.pdf (39kB)
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Attachment: gelbard1977 - Amberlyst Nitroethane - Copy.pdf (254kB)
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Attachment: palmieri2018 - Copy.pdf (3.7MB)
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[Edited on 18-4-2020 by Johnny Windchimes]
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S.C. Wack
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Aq. sodium ethylsulfate aka Krause reagent, or Auger's solution aq. potassium a-bromopropionate.
[Edited on 18-4-2020 by S.C. Wack]
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chemplayer...
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Very interesting references - interested to see if PEG400 works and if it is reproducible for some of the complex halo compounds used, as well as
whether or not it works for nitroethane.
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draculic acid69
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Firstly nice write-up. The price of silver salts and brominating ethanol make this a pretty expensive experiment.
I've thought about this.easiest way to nitroethane seems to be sodium ethylsulfate and nitrite. I'd buy the following things:
4litre of methylated spirits,jug of 2.5kg sodium carbonate, bucket of 3kg sodium bisulfate , a kg of sodium nitrite off ebay and a 6litre teflon
coated cooking pot. All available at big hardware stores and Walmart/Kmart or whatever u have wherever you are. With the cooking pot u should be able
to make a big batch of sodium ethylsulfate very easily. Whatever size batch u can do in a few hours in the cooking pot will be more than one could do
in a day using 1litre flasks and doing one batch after the other one could go through the whole sodium bisulfate pretty quickly giving enough
sodium ethylsulfate to do a batch big enough to yeild around a hundred mls instead of a small 7-15ml batch ppl usually do.seems easier than any other
methods to get nitroethane.
Using a glass diamond tipped drill bit to make a hole big enough in the lid to stick a few metres of 12 mm aquarium tube thru it is about all u would
need to do to make this pot work to reflux ethanol. Maybe u could connect a 1metre copper tube as a reflux condenser to a short length of aquarium
tubing which is stuck thru the hole in the lid. It wouldn't require much modification to get the pot working as needed.some thick teflon tape (the
pink or yellow stuff) should be enough to get a tight enough seal
around the edge of the lid to seal against the pot.
[Edited on 19-4-2020 by draculic acid69]
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Corrosive Joeseph
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I'd have to search but if I remember rightly, yields are about 8%
/CJ
Being well adjusted to a sick society is no measure of one's mental health
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clearly_not_atara
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| Quote: | | The holy grail is finding the conditions or OTC solvent that can do this with sodium nitrite. |
Anethole is way cheaper than silver and nobody ever seems to think about the anethole pseudonitrosite method. Only sodium nitrite is
required. The only other difficult chemical needed for the pseudonitrosite rxn is diethyl ether. Shulgin demonstrated the retro-Henry reaction using
alpha-methylbenzylamine but I imagine you could get pretty similar results with beta-phenethylamine or any of the other known methods for hydrolysing
a nitroalkene.
There is also a direct anhydrous cleavage of nitroalcohols:
https://www.thieme-connect.com/products/ejournals/pdf/10.105...
I am not sure if copper in wet conditions could catalyze the same thing but it seems interesting.
[Edited on 19-4-2020 by clearly_not_atara]
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Johnny Windchimes
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| Quote: Originally posted by clearly_not_atara | | Quote: | | The holy grail is finding the conditions or OTC solvent that can do this with sodium nitrite. |
Anethole is way cheaper than silver and nobody ever seems to think about the anethole pseudonitrosite method. Only sodium nitrite is
required. The only other difficult chemical needed for the pseudonitrosite rxn is diethyl ether. Shulgin demonstrated the retro-Henry reaction using
alpha-methylbenzylamine but I imagine you could get pretty similar results with beta-phenethylamine or any of the other known methods for hydrolysing
a nitroalkene.
There is also a direct anhydrous cleavage of nitroalcohols:
https://www.thieme-connect.com/products/ejournals/pdf/10.105...
I am not sure if copper in wet conditions could catalyze the same thing but it seems interesting.
[Edited on 19-4-2020 by clearly_not_atara] |
Interesting, I saw that you advocated for this method in another Nitroethane thread in 2019. Let me see if I can dig it up....
http://www.sciencemadness.org/talk/viewthread.php?tid=40137&...
There we are. Yeah looks interesting I'll dive into that one too. It's a quiet Sunday so I'll start with this great piece on Nitroso compounds by
Gowenlock.
Attached below~
Unfortunately if anyone was to need gallons of Nitroethane they would need to rely on one of the industrial processes miniaturized. Bubbling propane
through heated Nitric Acid and then shoving it all into a 450 C heated tube sounds super safe and fun to me.... But I don't think my wife would want
that device in our garden shed.... or anywhere on the property in general .
These boys tried a mini propane heated nitration and man what a ton of work. Paper attached below~
I don't need gallons, but it would be nice to find a reasonably scalable synthesis!~
Attachment: gowenlock2004 - Copy.pdf (448kB)
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Attachment: Multi-step processing in a microstructured flow reactor_ direct nitration of propane - Copy.pdf (2.1MB)
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[Edited on 19-4-2020 by Johnny Windchimes]
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clearly_not_atara
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JW: I'm not sure why the anethole method is so unpopular.
The pseudonitrosite reaction for nitration of styrenes has been developed extensively by... well, let's just say... entrepreneurs. It's easy to find a
number of amateur reports if you Google "pseudonitrosite erowid".
The "Pseudonitrosite FAQ" describes alkali workup of the initial addition product in alcohol:
https://erowid.org/archive/rhodium/chemistry/pseudonitrosite...
"0.1 mole of the corresponding propenylbenzene pseudonitrosites (28.5g asarone, 23.8g isosafrole or 22.4g anethole) was dissolved in 150ml 8%
alcoholic KOH with shaking, and possibly light heating (not over 30°C, especially not in the case of asarone pseudonitrosite, or there is a risk of
decomposition (to the aldehyde, amongst other things)."
It appears that simply warming up the reaction mixture is enough to cleave the nitrostyrene, at least if there is sufficient water available for the
hydrolysis reaction. If the aldehyde is subsequently immobilized by adding bisulfite, it should be possible to obtain the nitroethane directly from
this reaction mixture. KOH will deprotonate nitroethane, so it should be carefully neutralized (e.g. AcOH, not HCl) to prevent a Nef reaction.
Just a quick comparison of molar masses:
Silver: 107
Anethole: 148
so overall you need 1.4 g of anethole to replace 1 g of silver, which means it really isn't that inefficient.
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Johnny Windchimes
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Just a few additional references:
Gabrielli was apparently a student of Ballini (Dr. PEG-400 above), and her PhD thesis has a few extra references in it, although nothing overly new in
itself.
McNulty uses phosphonium salts as the Ionic Liquid (PEG-400 was Ballini's choice for Ionic Liquids if you recall). Old Man Crumbie was more into
nitro-ketones but he used the Amberlite-IRA-900 ion exchange resin as well, and there's a few AgNO2 blurbs and one about Phloroglucinol a la'
Kornblum.
Once my PEG-400 arrives I'm jumping right in and will take pictures this time!
Attachment: Gabrielli PhD Dissertation - Copy.pdf (1.8MB)
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Attachment: crumbie1982 - Copy.pdf (777kB)
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Attachment: mcnulty2006 - Copy.pdf (173kB)
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outer_limits
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I'd say that it's expensive only because of silver and it's salts prices. But sometimes you can buy some good quality silver fairly cheap and make
silver nitrite on your own. So the costs could be reduced.
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draculic acid69
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| Quote: Originally posted by outer_limits |
I'd say that it's expensive only because of silver and it's salts prices. But sometimes you can buy some good quality silver fairly cheap and make
silver nitrite on your own. So the costs could be reduced. |
I can get silver at a great price but buying silver and whatever else to make it takes time and the costs add up.i don't think it is as easy as
nitrate.then making 6+ moles of bromoethane =more time and money.
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clearly_not_atara
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| Quote: | | I can get silver at a great price but buying silver and whatever else to make it takes time and the costs add up.i don't think it is as easy as
nitrate.then making 6+ moles of bromoethane =more time and money. |
If there is one thing that seems to be the rule with nitroethane, it is that lazy people get no yield. The ethyl sulfate route works well when it is
performed with a well-planned setup and careful technique. Antoncho's method is news to nobody.
Of course, the anethole route is still much easier. I plan to type that sentence approximately five thousand times over the next ten years.
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Johnny Windchimes
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| Quote: Originally posted by clearly_not_atara | | Quote: | | I can get silver at a great price but buying silver and whatever else to make it takes time and the costs add up.i don't think it is as easy as
nitrate.then making 6+ moles of bromoethane =more time and money. |
If there is one thing that seems to be the rule with nitroethane, it is that lazy people get no yield. The ethyl sulfate route works well when it is
performed with a well-planned setup and careful technique. Antoncho's method is news to nobody.
Of course, the anethole route is still much easier. I plan to type that sentence approximately five thousand times over the next ten years.
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500 ml of Anethole oil ordered as well It wasn't too bad of a price.
This thing, as you've posted it (and I've looked into as well), is rather "Hivey".... like you did mention. Nothing wrong with that at all, but some
stuff there is a bit shaky on the details.
This one seems decently descriptive though. I can see the Nitropropene angles for their purposes, and I suppose by decomposing / hydrolysing at the
end I'd essentially be "ruining" the proposed drug synthesis and ending back up with the 'starting' nitroethane, insofar as 'starting' can be
ascribed.
I like the idea of using bisulfite to adduct out the aldehyde right in the same pot too, then filtering, seems slick.
If you add in the electro-synthesis of nitroethane (oh yes, I'm totally going after these 2 sentence throwaway blurbs from 1895 involving sodium
propionate and sodium nitrite I saw in a google book search baby!!), I'll have my hands full!!
I've attached Hofer's Electro paper. It's in German. I'll havta have it translated to get the experimental procedure with a hope of recreating it, any
helpful German volunteers?
PEG-400 first!
 
[Edited on 23-4-2020 by Johnny Windchimes]
Attachment: 10.1002@cber.18950280322 - Copy.pdf (676kB)
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[Edited on 23-4-2020 by Johnny Windchimes]
[Edited on 23-4-2020 by Johnny Windchimes]
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