02-13-01 15:03
No 173090
Hi bees, have been investigatring methods of manufacturing nitroethane and would appreciate the advise of bees more knowledgable on the subject than I.
Have more or less narrowed it down to two routes due to availability (OTC) of chems and ease of proceedure.
#1 Sodium nitrite, Sodium ethyl sulfate and Potassium Carbonate. This one looks completely OTC (if you make your NaEtSO4) with a totally simple proceedure, heat to 125C and distill! WOW! Wee problem here though, there is no rxn solvent listed. That isn't right is it? Or does the NaEtSO4 spontaneously break down to diethyl sulfate (liquid)?
I am thinking maybe H2O as a solvent or maybe something with a higher BP than EtNO2 like DMSO or kerosene? Could somebee throw me a bone here, pls?
Downside to this one is that the NaEtSO4 preparation looks slightly involved (time consuming from OTC materials)
#2 Sodium Nitrite and Ethyl Bromide in DMF or DMSO
This one is not quite OTC but still looks good, except for the volume of solvent required and the extraction work at the end. Although on the upside Ethyl Bromide looks very simple to make.
Anyways both look relatively OTC, what are the upsides and downsides that a younger bee might benefit from knowing. As with the first time this bee played with Nitromethane she also finds the prospect of playing with Nirtoethane daunting, any safety tips?
Thanks for any and all help bees.
(Chief Bee)
02-14-01 00:45
No 173181
The sodium ethyl sulfate should be a solid, but it is probably low-melting, so at the reaction temperature I believe that the mixture is a melt. Also, there is no solvent needed, the reaction is what is called a "destructive distillation", where the reactants breaks down into product (nitroethane, which distils over) and residue (sodium sulfate, which stays in the flask).
http://rhodium.lycaeum.org
(Stranger)
02-14-01 16:15
No 173282
That! is wonderful news Rhodium. Thank you. I suspected, but was not sure. This also means that the rxn is very volumetrically efficient. YES! (That was my problem with the EtBr/NaNO2 route)
Does any bee know how this rxn might proceed. Is it very 'happening"? Also I assume that you will know when it is done when the distillation stops? or slows considerably? Looking for some idea what to expect here.
Is there any maximum batch size or a size at which yeilds begin to be affected?
The proceedure says to mix all reagent INTIMATELY; would grinding togather with mortar and pestle followed by screening reagents with a seive be sufficient to meet this criteria?
Thanks again bees!
(Hive Bee)
02-14-01 16:50
No 173289
Just as intimately as you can get and that sounds fine. This sounds quite a bit like making methylamine where solids are heated until a clear liquid are obtained then distilled. Should not be a very violent or dangerous reaction as long as some certain precautions are taken cause nitro e is more explosive than nitro m.
(Stranger)
02-14-01 19:35
No 173312
"as long as some certain precautions are taken cause nitro e is more explosive than nitro m. "
Such as? Are we talking something more than a blast sheild here?
Also am thinking that a rb flask on an oil bath to ensure temp doesn't get beyond the specified range is probably the way to go, sound reasonable?
As well, thinking mag stirring as opposed to boiling stones on this one, reasonable?
(Chief Bee)
02-14-01 21:21
No 173329
Don't forget to try this method out - http://rhodium.lycaeum.org/chemistry/alc
http://rhodium.lycaeum.org
(Hive Bee)
02-14-01 21:31
No 173333
Well alot of people here use ghetto shit like irons for heat and stuff so as long as you contain the fumes and make sure what you use for heat and whatnot doesn't produce sparks you should be able to rest at ease. Yea you want either a sand, or liquid bath something that will hold an even temp. An inert aptmosphere during the reaction couldn't hurt either. Can't say for sure about the stirring depends on the reaction but most all cases it will do if the bubbling gets out of hand turn up the speed to break up the size of the bubbles. Why go through all this trouble just for that crap anyway?
( )
02-14-01 22:46
No 173353
Rhodium! Do you mean to suggest that the proceedure with EtOH substituted for benzylalcohol as the starting material will yield nitroethane? except I assume it wouldn't be a gummy residue in that case. (WOW avec some tres cool thrown in!)
(Chief Bee)
02-14-01 23:42
No 173369
Yes, that is what the article suggests. As the reaction works in 87% yield for octyl alcohol (a primary aliphatic alcohol), it should work the same for ethanol.
You will have to modify the workup for nitroethane though. If you would rotovap the DCM/Nitroethane mixture, a lot of the volatile nitroethane would evaporate too.
In this case you will probably have to fractionally distill the reaction mixture, collecting everything that distills above 50°C, and then redistill that fraction.
This provided that DCM and nitroethane doesn't form an azeotrope.
http://rhodium.lycaeum.org
(Stranger / Eraser)
02-15-01 15:14
No 173510
The NaNO2/DMSO does not appear to work on EtBr.
The DMSO solvent seems to react, turning the reaction mixture into a H2O soluble crystaline mass.
( )
02-15-01 17:39
No 173531
A chemist decided to give that alcohol >> nitro synth a whirl last nite. A couple things become immediately apparent. This rxn is volumetrically unrealistic for any kind of scale up.
at 10X you have ca 4mls of EtOH in 300ml DCM and the proceedure reccomends adding another 1500mls DCM to crash out the NaOAc. FUCK ME, that is a buttload of solvent!
I'm not writing this one off, but there are some problems here.
1. NaNO2 does not come anywhere near going into solution, it isn't even a suspension, it just sits on the bottom of the flask.
2. The HCl does not remain longer than a couple of seconds. Its addition results in an immediate release of a small amount of N2O3 (fine, but you want some ventilation.) I think that this is simply to initiate or kick start the rxn between the NaNO2 and AcOH which are close to equimolar quantities.
so this creates NaOAc and free NO and NO2 in solution, which I assume then attaches to the ethanol (very similar to the pseudonitrosite synth) to form the EtNO2.
3. without stirring, it appears that alot of the NaNO2 is unreacted as it becomes coated with a coating of NaOAc. So the chemist swirled the reactants a couple times.
4. The NaNO2 needs to be very finely ground I think.
Two runs were done, results will be posted pending work-up.
Here are a couple questions
1. Is the addition of DCM really required to crash out the NaOAc? seems like we have it precipitating without the DCM to crash it out.
2. If the addition of more DCM is skipped will the residual NaOAc get picked up in the water washs?
3. When scaling this one does the quantity of DCM need to go up at the same rate as the reagents? (I hope not)
4. The proceedure does not mention mixing the reactants prior to the HCl addition, should they be? It says not to after but how about before? The chemist did, we will see.
(Chief Bee)
02-15-01 18:57
No 173536
The NaNO2 should be converted to NaCl and NaOAc directly upon addition of HCl and HOAc, so it should not look like it goes into solution. Are you sure that the powder really still is NaNO2? The NaNO2 should be very finely ground, yes.
The amount of solvent does not need to be scaled up at the same rate as the reactants in my opinion. And yes, the DCM added to the solution to crash out NaOAc can be skipped, the inorganic salts will be removed by the water washes.
I believe that the reactants should be well stirred until the HCl is added.
You need to be careful when isolating the nitroethane, and pay attention to the following:
* The boiling point of nitroethane is 114-115°C (be careful when removing the DCM).
* The solubility of nitroethane in water is 4.5ml in 100ml at 20°C (the nitroalkanes in the article are water insoluble).
* It is unknown if nitroethane forms an azeotrope with DCM.
http://rhodium.lycaeum.org
( )
02-15-01 20:42
No 173544
No Rhodium, cannot say for sure that it was not converted immediately, simply there was no visible reaction when adding the HOAc and the appearance/consistency of the salt did not change during the prestir. However as soon as the HCl was added, there was visible evolution/effervecence of N2O3 with a white froth which became a white gummy substance on surface which eventually solidified and precipitated in a crystal structure similar to MgSO4 which has gotten wet, but subsequently driied again. The bulk of the filtered salt was of this altered form.
Further, when the mixture, was swirled at 4 hours and 12hrs there was fizzing and effervencense. This leads me to think there is unreacted salt. Perhaps it should have been finely powdered, which it wasn't.
Sounds like ice water washs are the way to go with the solublities you mention. Guess it wouldn't be a bad idea either to keep and reduce those washs later.
As far as scaling and reagent/solvent ratios, the current ratiois 1/60, would the 1/10 ratios be sufficient here?. With a 100-1000X scale-up in mind?
Another point occurs to me, is that perhaps it is not necessary to scale the amount of HCl as it appears to only kickstart the nitration. What is your opinion? It would be less N2O3 fumes to be concerned with.
(Stranger)
02-15-01 22:45
No 173571
Karl - does it run in DMF though? What do you think the crystalline mass is?
I remember reading about another bee who had a silmilar problem using Ritters method w/ phloriglunicanl dihydrate, NaNO2 and EtBr in DMSO. I beleive they said it was the formed NaBr causing the problem, dunno if there is a work around, but there must be. Filtration perhaps?
(Stranger / Eraser)
02-16-01 10:59
No 173680
In DMF it did not suffer from the same problem but yields were rather low, this may be due to the solubility of the nitro in H2O on extraction.
(Stranger / Eraser)
02-16-01 13:58
No 173693
I'm not sure what the solid was but there was barely any DMSO left. On standing for a period it appeared to decompose, liberating a small amount of nitrogen peroxide.
The formation of the solid was significanly exothermic, when the reaction was run at a lower temperature and the EtBr added slowly dropwise to avoid this overheating the medium progressively became more viscous until stirring stopped, solidification when about 3/4 of the total EtBr was added.
( )
02-16-01 19:25
No 173739
Stripped off the DCM under low vac on water bath, took up pale ochre coloured residue (smelled of HOAc) in 100ml hexane washed once with 100ml H2O (10deg C), stripped of hexane on water bath wth low vac. put 1ml remaining into a test tube which togather with a thermometer were placed in a oil bath. The contents of the test tube boiled when the thermometer read 116deg C.
Likely some was lost in the water washs, possible some was lost stripping off the DCM. But there was something in the 20% neighbourhood, having made several mistakes.
What do other bees think will be the determining factor as to how little solvent can be used? Would it be the amount of solvent rqd to hold the amount of NO2 freed by the acid? How could that be determined, the solubility of NO2 in DCM?
(Hive Bee)
02-17-01 00:01
No 173790
Man, I already got my hands on 500ml of this stuff (lab grade) and have no use for it. It is way beyond my chemical adeptness to use this for anything. If your willing to put up some good g's Ill hand it over.
(Hive Addict)
02-21-01 01:00
No 174533
Here piggy piggy
Oink oink
Do Your Part To Win The War
(Newbee)
02-22-01 01:34
No 174754
Exchange your ideas here, not your chemicals. No selling.
-quicksilver-
Poster: scram
Subject: Re: Roads to Nitroethane
Man, I already got my hands on 500ml of this stuff (lab grade) and have no use for it. It is way beyond my chemical adeptness to use this for anything. If your willing to put up some good g's Ill hand it over.
(Hive Bee)
02-23-01 11:55
No 175012
provided that DCM and nitroethane doesn't form an azeotrope
This came from some azeotrope didicated webpage:
Binary azeotropes of:
(substance/bp/comp.wt%-wt%)
Nitroethane:
1-butanol/107.7/55-45
toluene/106.2/25-75
DCM:
glycol/168.7/86-14
They don't claim to list all existing azeotropes, but they list so many that I don't think DCM/nitroethane will form one.
Hansje Pansje Kevertje.....
(Chief Bee)
04-08-02 19:55
No 294279
See ../rhodium/pdf /nitroalcohol.
(Hive Bee)
04-08-02 21:23
No 294306
hi ab2,
don't bee angry on otto, but it seems that all your effort was useless. check out Synlett; 07, 2001, pp 1121-1122 the article "Can Nitroalkanes be Obtained Directly from Alcohols and Sodium Nitrite in Acetic Acid - Hydrochloric Acid Mixture?" says that it isnt possible, instead of nitroalkanes they always got the corresponding nitrite esters. you can get the .pdf from www.thieme-connect.com, when you sign a trial-account.
otto
(Chief Bee)
04-08-02 21:42
No 294313
Otto: Uh? I have uploaded exactly that PDF to my website above.
(Hive Bee)
04-09-02 02:03
No 294381
Hey Rhodium, "this method is history..." are you saying that it doesn't work?
(Chief Bee)
04-09-02 14:18
No 294605
Yes, and why it is so is detailed in the PDF file I linked to (it is the PDF version of the article otto refereced).
(Hive Bee)
04-10-02 00:04
No 294748
So, if we can in good yeild produce ethyl nitrite- why not? It is easy enough to convert to nitroethane by isomerization, right? ../rhodium /nitrite
didn't read the whole thing, so if there is a reason that this is hard to do, please state.
(Chief Bee)
04-10-02 01:36
No 294769
It is much easier to produce ethyl nitrite than using the method described in the article, just look at my page - ethanol, NaNO2 and H2SO4 - no need for DCM/HOAc.
The isomerization method is indeed theoretically easy, but not suitable on a small scale.
(Hive Bee)
04-10-02 05:59
No 294865
So what do you think the minimal size would be? and how to make it "safe".
(Hive Bee)
04-10-02 06:10
No 294867
Rhodium, as is the usual case, is correct. the percent yeild really isn't that bad (10% of nitroethane by volume) considering the recycling for repeated attempts for converting the rest of the nitrite. However, the article stated that it took 4-5 HOURS to pass a relatively small (less than a liter) of nitrite through. if one had a continuous still (dangerous) aurelius could see the benifit. But as Rhodium stated- not for small scale.
(Hive Bee)
04-10-02 06:16
No 294869
Just thought it was appropriate
Post 238118 (Aurelius: "Re: What can be done to improve the performance of clandestine nitroethane synth?", Chemistry Discourse)
(Hive Bee)
04-10-02 06:28
No 294875
SWIM did 3 batches of this stuff... All of her distilled products had a density of around 2g/ml.. She vac distilled, distilled @ 1ATM, and lastly, distilled with water.. Any other bees (that bothered to mass the distillate) have this problem??
(Hive Bee)
04-11-02 00:17
No 295186
hi rhodium,
before otto started to type your post wasnt there. then some people came in drawing otto off the computer for a talk and otto of course didnt check again the forum before finishing the post.
otto