Sciencemadness Discussion Board

Nitroalkane syntheses ?

chemoleo - 10-12-2004 at 12:28

I was wondering, not for the first time, which general methods are available for the production of simple nitro alkanes.

I can see two routes for this:

1) R3C-NH2 --> oxidise --> R3C-NO2.

2) R3C-Cl/Br/I + NO2- --> R3C-NO2 + Cl/Br/I-

where R is H or whatever.

I know that both reactions have been shown to work, but particularly in the latter case I failed to find references as to what conditions exactly need to be employed.
For instance, tetranitromethane can be made by the reaction of iodopicrin I3CNO2 with AgNO2. What reaction conditions are supposed to be employed there? I.e. iodopicrin is surely insoluble in water, so to facilitate the reaction with silver nitrite would be tricky. Equally, how about the reaction of chloroform with AgNO2? The former is definitely not soluble, so how can one go about to get the reaction to work?
Alternatively, how about chlorination of ethylene to form 1,2 dichloroethane... and to react this with AgNO2.
I take it the reason why the Ag, rather than the Na/K nitrite is chosen is because the former is highly insoluble, thus shifting the equilibrium of the reaction faster to the right.

As to reaction scheme 1) - the oxidation of amines - what are the generic conditions there? I.e. what if the starting compound was ethylenediamine H2N-CH2CH2-NH2? It's a liquid, soluble in H2O and highly basic.

Any help on this would be appreciated.:)


[Edited on 21-11-2006 by chemoleo]

UpNatom - 10-12-2004 at 13:38

1. CH3CH(OH)COOH + HBr ------> CH3CH(Br)COOH + H2O
2. CH3CH(Br)COOH + NaNO2 ------> CH3CH2NO2 + NaBr + CO2

Although not really answering any of your questions chemoleo, this is a rather elegant specific nitroalkane synthesis don't you think? ( I'm not sure if the first step has been proven in practice, but I see no reason for it not to work well.) I'm almost 100% certain I've seen the second step reported to yield ~70%. It's essentially the same synthesis described in Vogel for NM but from a fantastically OTC starting point.

Ref: Nitroalkenes

solo - 10-12-2004 at 13:53

Gilbert found a general high yield synthesis of nitroalkanes from amines using m-chloroperbenzoic acid(m-CPBA) at elevated temperatures.

Ref.
J. Org. chem. 44, 659, 1973
Gilbert.,E. and W.T. Borden

as read in The Nitro Book in Organic Synthesis by Noboru Ono, Wiley-VCH 2001 pg.20

Ref: Nitroalkenes

solo - 10-12-2004 at 14:51

Rhodium has an unfinished page with many FAQ on the synthesis of nitroalkanes....you may already know this if not here it is....solo


http://web.archive.org/web/20040213224536/www.rhodium.ws/che...

Marvin - 10-12-2004 at 15:15

Organic reactions volume 12 is best Ive read on the subject.

A quick summery or preffered methods.

Primary nitroalkanes,

Silver nitrite, alkyl halide. Br or I, DMSO or DMF
Sodium nitrite, alkyl halide. Br or I (Cl may work here I forget), DMSO or DMF,
Aldoxime+ peroxytrifluoro acetic acid.

Secondary nitroalkanes.

Sodium nitrite and alkyl halide (or sulphonate ester).
Amine, peracetic acid.
Ketoxime oxidation.

Tertiary nitroalkanes.

Permaganate (or peracetic acid) + t-carbinamines.

a-nitro esters.

Sodium or silver nitrite, a-haloester.
Acetone cyanohydrin nitrate, sodium enolates of malonic or acetoacetic esters.

The rest is pretty fringe. There may be an electronic copy of this on the FTP, I dont remeber. This volume is forthcoming in electronic form according to several posts anyway.

Yeilds depend much on the solubility of the chosen nitrite in the organic solvent, DMSO and Silver nitrite is best I think. For less soluable mixtures nitrous ester scavengers have to be added to suppress furthur reactions (urea works well).

S.C. Wack - 10-12-2004 at 15:47

Just in case, another Rhodium archive:

http://web.archive.org/web/20040213203724/www.rhodium.ws/che...

Refa; Nitroalkanes

solo - 10-12-2004 at 18:10

In the search function under nitroalkanes I found some interesting material......solo
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posted on 13-11-2003 at 11:02 PM


nitroalkanes via nucleophilic substitution

primary alkyl halides yield mostly nitroalkane. the secondaries yield 15% nitroalkane and tertiary alkyl halides practically don't produce nitroalkane but the nitrous ester.
just found a general procedure for preparation of nitroalkanes in "Organikum, organisch-chemisches grundpraktikum" :
add 0.3 mol alkyl halide to a mix of 0.5 mol sodium nitrite and 0.5 mol urea (increases soloublity of the nitrite in dimethylformamide) in 600 ml dimethylformamide. mechanically stir at room temperature for 1-6 hour (depends on reactivity of the halide). pour the mix on 1.5 L ice water, extract with ether several times, dry on calcium chloride, then perform a fractional distillation using a 30cm vigreux column. the nirous ester by product comes first (has lower bp)
"ethylene chlorohydrine is of course a primary alkyl halide"
when using ethylene chlorohydrine in above procedure. 2-nitroethanol and ethylene glycol mononitrite are expected to form. and both are liquides with high bp. so one can warm the whole batch at 120°C to tautomerise the glycol nitrite to 2-nitroethanol
the nitroethanol can further react with formaldehyde to form trimethylolnitromethane and this makes NIBGTN upon nitration.

PJFF
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chemoleo - 11-12-2004 at 16:12

Ok, thanks a lot for the excellent information.

Essentially this seems to boil down to the following:

1) Alkylhalide + NaNO2, using DMF or DMSO as a solvent
2) Alkylhalide + AgNO2, using dry ether.
3) Alkylsulphate (only the Et-sulphate was quoted, but no other alkyllsulphates) and NaNO2, and straight distillation (seems easiest if ethylsulphate is ample)
4) Dialkylsulphate and NaNO2, distillation again but slow reaction.
5) Alkylamine + peracids (i.e. perbenzoic acid), in 1,2 dichloroethane
6) Alkylamine + KMnO4 - OrgSyn only mentions this method in conjunction with amines attached to tertiary carbons.
7) various others, exotic ones.


Re. the halides, the bromides and particularly iodides seem to be preferred over the chlorides.
The KMnO4 oxidation method mentions a few references, does anyone have access to these:
Org Synth CV 5, 845 (somehow I couldn't access it)
There is a list of others under Method 6, if anyone's got access to those that seem relevant/feasible, please do post!

I am surprised anyway that there aren't widespread oxidation protocols available, with the various oxidation agents that exist!
KMnO4 doesn't seem to work well (except tertiary amines), and peracids aren't exactly easy to make/obtain.

Anyway, it seems that making nitroalkanes will almost certainly require decent amounts of solvents :(


Edit: Thanks for pointing this out, yes, I meant a primary amine on tertiary carbon in 6)

[Edited on 13-12-2004 by chemoleo]

BromicAcid - 11-12-2004 at 19:33

Quote:
2) Alkylhalide + AgNO2, using dry ether.
Some preps I have found use acetonitrile instead of ether. Particularly the preparation of trimethylsilyl nitrate and nitrite, a fine precipitate of AgCl appears instantly in this method.

Mendeleev - 12-12-2004 at 11:30

"6) Alkylamine + KMnO4 - OrgSyn only mentions this method in conjunction with tertiary amines. "

Are you sure this works? I thought it required a primary amine, and I could not find any reference to it on orgsyn.

Marvin - 12-12-2004 at 21:09

Tertiary amine is the wrong term, that would indicate a NR3 type compound. He means an amine on a tertiary carbon and the term for that I've posted t-carbinamine. It might have helped if I'd explained it.

(from the quote of the KABOOM post)
"so one can warm the whole batch at 120°C to tautomerise the glycol nitrite to 2-nitroethanol "

This wont work, nitrites do not convert to nitro compounds. There is missleading information on Rhodiums site on this, it isnt true.

When does the edit function expire

UpNatom - 13-12-2004 at 13:39

I was hoping to add this to my post above but cannot. Anyway...

This is the original text by aurelius on method 17 from the compilation.
Quote:
Method 17: Distillation of alpha-bromopropionic acids with NaNO2 in the presence of Magnesium Sulfate in DMSO

US pat # 4319059

(the alpha-bromo acid can be obtained using propionic acid in the procedure from Org. Synth. CV 1, 115.)

This patent shows an easy route from alpha-bromopropionic acid to nitroethane in excellent yield. The patent also say that Magnesium chloride, bromide or sulfate may be used instead of the magnesium methoxide, but it doesn't say if this affects yields.

The reaction proceeds as follows: In the polar aprotic solvent DMSO, the alpha-bromopropionic acid reacts in an SN2 fashion with nitrite ion to give alpha-nitropropionic acid and bromide ion. The role of the Mg2+ ion in the reaction is to facilitate the decarboxylation (removal of CO2) from the intermediate nitro acid, as it forms a chelate between one of the oxygen atoms on the nitro group and the oxygen anion of the carboxylic acid. The electron-withdrawing nature of the nitro group makes the carboxylic acid group labile, and it can easily be given off as carbon dioxide. If magnesium methoxide is used in place of the other magnesium salts, the carboxylic acid is directly deprotonated, probably making the reaction go even faster.

There is no workup mentioned in the patent, but I'd suggest flooding with water (or using large amounts of dilute (5%) HCl in the hydrolysis step), and then extract the nitroethane with dichloromethane, ether or possibly petroleum ether. Then the combined organic layers are washed first with water and then with a concentrated NaCl solution, followed by drying the organic phase over anhydrous MgSO4, which is then filtered off. Then the solvent is removed distilled, and the residual crude nitroethane is fractionally distilled at 114-115°C.

alpha-Bromopropionic acid can be made from propionic acid and phosphorous tribromide (from red phosphorous and bromine, the Hell-Volhard-Zelinsky reaction, http://www.geocities.com/chempen_software/reactions/RXN099.h... or http://www.orgsyn.org/orgsyn/default.asp?formgroup=base_form... , or by HBr bromination of lactic acid (alpha-hydroxypropionic acid).
[uNa: the gist of my post further up this thread]

Example 1

To a mixture of magnesium methoxide (0.11 mole) and dimethyl sulfoxide (50 ml) a-bromopropionic acid (0.11 mole) was added at 20°C. with stirring. To this mixture a solution of sodium nitrite (0.145 mole) in dimethyl sulfoxide (65 ml) was added at room temperature. Then, the reaction mixture was stirred at room temperature for 6 hours and was neutralized upon addition of diluted hydrochloric acid. Analysis of the reaction mixture indicated more than 99% conversion of alpha-bromopropionic acid and 94.5% yield of nitroethane.

Example 2

In the manner of Example 1, sodium nitrite, alpha-bromopropionic acid and magnesium methoxide were reacted in dimethyl sulfoxide as the aprotic solvent. The reaction time was 2 hours for one run and 22 hours for another. Reaction was conducted at room temperature. The run at 2 hours converted only 94.5% of the acid and yielded 72.7% nitroethane. The second run at 22 hours gave a conversion of > 99% and a yield of 100%.


It's by this method I'm certain I have seen 70%+ yields from experimenters (not quite the >99% mentioned, but not bad) and lactic acid is a cheap homebrew chemical. Pity DMSO isn't so OTC (outside the US anyway) Worth a try if its specifically NE you're after.

Mendeleev - 14-12-2004 at 19:03

Preparation of Diethyl Sulfate
Procedure

Ninety grams of sodium sulfate is placed in a dry 1 liter flask connected with a condenser and a receiver arranged for vacuum distillation. The flask is heated by means of an oil bath to 155-165°C. The apparatus is exhausted as nearly as possible by means of a filter pump, and misture of 50 grams of ethanol and 104.5 grams of concentrated sulfuric acid is allowed to drop through a capillary tube on the sodium sulfate at a rate of 120-150 drops per minute. The distillation of the mixture requires about one and one half hours for completion. The distillate, which consists of ethanol and diethyl sulfate is poured into a separatory funnel, the ethanol may be recovered for further use. The diethyl sulfate is washed with a dilute solution of sodium carbonate and then several times with cold water, then dried with anhydrous sodium sulfate, yielding 32.4 grams.

Reference: JACS 46, 999-1001 (1924)



Will that work with magnesium sulfate?

Mendeleev - 15-12-2004 at 06:41

http://chemlabs1.tripod.com/chemistry/alcohol2nitro.html

Preparation of Nitroalkanes Directly from Alcohols

--------------------------------------------------------------------------------



Spengler described the synthesis of a few simple primary and secondary nitro aliphatic nitro alkanes using a mixture of NaNO2-H2O-HCl,however their method was not tested on a wide varity of substrates including tertiary alcohols. In continuation of our interest on the chemistry of nitro aliphatics and their application in the synthesis of bioactive natural products, we have observed that when a mixture of NaNO2-AcOH-HCl is treated with a varity of alcohols the corresponding nitro compounds are formed in excellent yields. The results are shown in the table below.

Substrate Reaction time Product Yield
Benzyl alcohol 6h Phenylnitromethane 85%
1-Phenylethanol 5h 1-Phenylnitroethane 90%
4-MeO-Phenethylalcohol 6h 4-MeO-Phenylnitroethane 90%
4-Cl-Phenethylalcohol 6h 4-Cl-Phenylnitroethane 87%
Octyl alcohol 6h Nitrooctane 80%

Typical Procedure:
To a mixture of the benzyl alcohol (9.24 mmol) in CH2Cl2 (30 mL) was added NaNO2 (2g, 29 mmol). To this mixture was added acetic acid (1.5 mL, 26.2mmol) and left at room temperature for five minutes. Then concentrated HCl (0.5 mL) was added to this mixture and left at room temperature without stirring for about 14 hours while monitoring the reaction on TLC. The reaction mixture was diluted with CH2Cl2 (150mL) and the preceptiated NaOAc was filtered off. The organic phase was evaporated in a rotavapor and the gummy residue was dissolved in hexane (100 mL) and washed with cold water (5x200ml) to remove the acid. The organic phase was dried over anhydrous sodium sulfate to furnish the nitroalkane.

Reference: Synlett, No. 7, yr 2000, pages 1064-1066




This is a very simple procedure, will it work with ethanol?

[Edited on 15-12-2004 by Mendeleev]

Marvin - 15-12-2004 at 16:42

I was thinking for some considerable time that I'd made a horrific mistake and I should give up chemistry and make baskets out of reeds for a living. The claim makes no sense with regard to conventional chemistry.

Then after much searching I found this abstract.
Quote:

Can Nitroalkanes be Obtained Directly from Alcohols and Sodium Nitrite in Acetic Acid - Hydrochloric Acid Mixture?

Mieczysław Mąkosza*, Michał Barbasiewicz, Krzysztof Wojciechowski
*Institute of Organic Chemistry Polish Academy of Sciences, ul. Kasprzaka 44/52, P.O.Box 58, PL 01-224 Warszawa 42, Poland; E-mail: icho-s@icho.edu.pl


The report that nitroalkanes can be obtained from aliphatic alcohols and sodium nitrite in acetic acid - hydrochloric acid mixture was shown erroneous. Under these conditions no nitroalkanes but alkyl nitrites were formed.


Dated a year after that information in the same journal and presumably in reply to it.

So will it work with ethanol? No. It doesnt even work with any of the substances listed.

not that good in practice

Vitus_Verdegast - 16-12-2004 at 08:00

Destillation of an intimate mixture of Na alkylHSO4, NaNO2 and a dash of K2CO3 seems to work, but yield is low for nitromethane, and even lower with nitroethane.
It's the most OTC way though, IIRC Antoncho or another Russian did some interesting experiments with at the Hive.

Use one of the patented methods to make NaEtHSO4 from ethylsulphuric acid (EtOH/H2SO4/MgSO4), instead of the cumbersome and horribly messy route via the calcium salt.. You just need to monitor the pH constantly on basification, as water + acid will hydrolize a great part of your ethylsulphuric acid.

[Edited on 16-12-2004 by Vitus_Verdegast]

Mendeleev - 16-12-2004 at 14:34

Have you read the msds for diethyl sulfate? It is one nasty-ass carcinogen. I would much rather go the sodium ethyl sulfate route, just because it's not as toxic.
http://www.weblakes.com/toxic/DIETHYL_SULFATE.HTML

[Edited on 16-12-2004 by Mendeleev]

Diethyl Sulfate

FloridaAlchemist - 16-12-2004 at 17:47

Diethyl Sulfate is not too dangerous to use. It is one of the byproducts when you make Diethyl Ether. Dimethyl Sulfate is the dangerous one:o

Mendeleev - 16-12-2004 at 18:30

Maybe not dangerous as in kill you in a few seconds due or make you violently ill, but it seems like it is a very nasty carcinogen.

sparkgap - 16-1-2005 at 05:13

In any case, both are freakishly good alkylating agents, so they'll most likely muss up you DNA. Right up there with the mustards and alkyl bromides/iodides

Wait a minute...

QUOTE from FloridaAlchemist

...It is one of the byproducts when you make Diethyl Ether...

Just how?

Yes diethyl sulfate

FloridaAlchemist - 16-1-2005 at 10:53

Diethyl sulfate and ethyl hydrogen sulfate are intermediate esters formed when ethyl alcohol and sulfuric acid are reacted together.. The conditions of the reaction ,and /or conc of the sulfuric acid is what determines if you get diethyl ether or the sulfate esters.:o
Show me the references where diethyl sulfate messes up your DNA or for that matter a carcinogen.
Comparing diethyl sulfate to dimethyl sulfate is like comparing methyl alcohol to ethyl alcohol.

sparkgap - 18-1-2005 at 00:57

Yeah, I found out just the other day when I researched industrial scale preparation of ether. Thanks for answering my question.

The key word was "most likely" in my comment on mutagenicity/carcinogenicity.

All the MSDS's I've seen on lower alkyl sulfates say they're either carcinogens/mutagens or suspected carcinogens. As far as I know, I was confident in my remark since both dimethyl and diethyl sulfate have the alkylsulfate moiety, which makes them susceptible to nucleophilic attack.

My second beef, the analogy you gave, doesn't make much sense to me. Both alcohols are toxic at the proper doses. What distinguishes methanol from ethanol in terms of toxicity is in the metabolites they produce. In the case of methanol, formaldehyde and formic acid are the metabolites that deal heavy damage to the unfortunate swigger. Ethanol is oxidized by alcohol dehydrogenase in the liver, however, to acetaldehyde (one of them hangover culprits) and acetic acid (p.u.!).

The alkyl sulfates, on the other hand, are both susceptible to SN2 attack. It's in the functional groups, dude.

Damn, this post is too long...

My two cents worth.

sparky

[Edited on 18-1-2005 by sparkgap]

Comparison

FloridaAlchemist - 18-1-2005 at 18:06

The comparison I was giving was just for comparing relative toxcity in a general way, of the alkyl groups methyl versus ethyl . ie methyl alcohol more toxic than ethyl alcohol... or dimethyl sulfate being more toxic than diethyl sulfate.

sparkgap - 19-1-2005 at 06:56

Or to make your statement more precise, you were referring to acute toxicity. In that regard, I have to agree with you regarding both the alcohols and the alkylsulfates.

However, I still stand by my statement regarding DNA damage. I believe that is in the chronic toxicity department. DNA damage is not a readily apparent sign in humans, except in a few special cases.

But we're going off-topic here. I'm kind of surprised the admins aren't screeching at us for this. :)

The only nitroalkane synthesis I can attest to is the route from chloroacetate. It's quite clean. Then again, I do this not in my home lab, so that might make a difference. Maybe I'll try the backyard synthesis one of these days.

sparky

sparkgap - 21-1-2005 at 08:54

Just found a book on nitration by George Olah. Got it from our library. Here is a link about it:

http://as.wiley.com/WileyCDA/WileyTitle/productCd-0471186953...

When I get to reading it, I'll be posting a bit.

Till then,
sparky

That book looks promising

Joeychemist - 21-1-2005 at 08:59

Sparkgap, when you find time could you maybe scan the book and upload it to the ftp please???:);)

I'm sure we would all be gratefull:)

sparkgap - 21-1-2005 at 09:17

You're too formal. Call me sparky. ;)

Anyway, I don't have a scanner handy. I'll just quote the book after I read it cover to cover. I don't think all the syntheses Olah describes are appropriate for a makeshift lab, if you get my drift.

Anyway, it should be good overall. Olah learned quite a bit on this subject from Sir Christopher Ingold, the father of modern nitration chemistry.

sparky

Maja - 17-5-2006 at 00:15

Quote:
Method 10: ethyl bromide, DMSO, NaNO2 and phloroglucinol dihydrate

By Ritter, in Strike's book- TSII.

32g or 26ml EtBr is poured into 250ml of DMSO with 36g NaNO2 and 52g phloroglucinol already present in solution.(Pglucinol is expensive but can be recycled) put on good mag. stirring and stopper the flask. Stir for two hours in emulsion form, then dump into a 600ml of ice water and extract twice with DCM. (2x200ml) dry the extracts withMgSO4 or CaCl2 the evap off the DCM. Distill and collect the fraction from 113-116°C--- yields about 20g of nitroethane (80%)(another ref says maybe over 90% consistently)
Other notes:catechol and resorcinol have the same nitrite scavenging abilities as phloroglucinol. And ethylene glycol can be used as a solvent. A simple NaOH wash of the final solution (nitroethane removed) will give the sodium salt of your phloroglucinol catalyst. Acidification of the solution will precip the catalyst for recovery by filtration.


This is from rhodium. Looks likequite simple. Resorcinol is easily available to me. If yiels are so go as stated... I will give it a shot. Maybe someone tried it before ? Comments ? Suggestions ?

Maja - 21-5-2006 at 02:57

Absolutely confused ! Tried to follow nitroethane synth in previous my post in this thread. dissolved NaNO2 and Resorcinol in 260ml DMSO and added Ethyl bromide at once...All liquid changed color from yellow to slight orange. Started to mix it manually for a few minutes and then left it to rest in dark place for 24h mixing it occasionally. After night at flat bottom flask was ......... See yourself : http://img163.imageshack.us/my.php?image=upsidedown1qw.jpg

Hard plastic like thing(almost the same as in red plastic synth with NaOH , CH2O and resorcinol...) I don't want to break that flask :o Someone wanna try it ?

Nicodem - 21-5-2006 at 09:19

It has been said several times at The Hive that this procedure does not work and that the reaction mixture simply solidify to some unknown crap. I would assume it has to do with the fact that ethyl bromide is known to react with DMSO. Glycol has been proposed in certain Rhodium's pages, however ethyl bromide is not miscelabile with it. Rather use DMF instead.

The_Davster - 27-9-2006 at 19:24

I thought of a potential route to nitromethane today, diazotize glycine, react with KI for the iodoacetic acid(which I think has other uses as well), followed up by a reaction with nitrite to form the nitroacetic acid(ala the standard chloroacetic acid procedure, but iodine should come off a bit easier, and introduction of iodine via diazotization is easier) which decomposes into nitromethane.

Or oxidize glycine somehow, but the glycine oxidation thread did not seem to have any results with this.

cyberzed - 19-11-2006 at 13:48

Hi, having seen some idea's here and some references i dug up the synth for nitroethane by reacting sodium ethyl sulfate and NaNO2 under a catalyst of Kalium Carbonate.
I have seen some warnings about the formation of unstable nitrite esters which could form in a distillation setup.
I was wondering if someone could point out the dangers in this particular synthesis?

1.5 mole sodium nitrite (103.5g) is intimately mixed with 1 mole of sodium ethyl sulfate (158g) and 0.0625 moles of K2CO3 (8.6g). The mixture is then heated to 125-130?C, at which temperature the nitroethane distills over as soon as it is formed. The heating is discontinued when the distillation flow slackens considerably, and the crude nitroethane is washed with an equal amount of water, dried over CaCl2, and if needed, decolorized with a little activated carbon. The nitroethane is then re-distilled, collecting the fraction between 114-116?C. Yield 46% of theory

(another ref says max. 42%)
Chemical Abstracts, Vol 49, pg 836.

Boomer - 20-11-2006 at 05:15

There is an error in that method, read yourself (from one of the few good threads on WD):


Evil lurker:

Nitroethane, that substance which is so cheap at any chem supply house, but so damn hard to get. Making the stuff ain't very much easier than buying it from the recipes on the net.

The two OTC easiest ways, using sodium ethyl sulfate and diethyl sulfate as reagents are very hard and dangerous to manufacture. The problem lies in the water molecule the ETOH creates when it forms the ester. The apparatus looks plain scary to operate, and creates diethyl ether as a side product and the yields suck ass!

But now that problem has been fixed. Sodium ethyl sulfate can be easily prepared in the home laboratory from common sodium bisulfate found in pool pH down and 95% pure grain alcohol, and baking soda or sodium carbonate found in pH up.

113 parts by weight of sodium bisulfate and 20 parts by weight of pure grain alcohol are combined in a flask and brought to boiling upon which time the sodium bisulfate crystals disappear and sodium sulfate forms.

When the reaction has been completed, the flask was is immersed in an ice bath and vigorously stirred until the tempurature rapidly goes below 32.3C.

The formed sodium sulfate is thus filtered out leaving an anhydrous ethyl hydrogen sulfate/ethanol mix.

The excess ethanol is distilled off, and the ethyl hydrogen sulfate is neutralized with an appropriate quantity of sodium carbonate leaving sodium ethyl sulfate.

Simple... thats all there is to it! The secret to how it works is the excess sodium bisulfate when rapidly cooled below 32.3C forms the decahydrate, or Glaubers salt, and this sucks the water out of the reaction.

This is discussed futher in US Patent number 3,024,263.

Nitroethane can now be easily worked up according to this synth:

1.5 mole sodium nitrite (103.5g) is ... (here comes the synth you posted) ... Yield 46% of theory.

There ya have it folks, nitroethane cheap and dirty, from nearly all OTC chemicals.



Pelnicki:

Three QUESTOINS (which are good ones)

1. Does anyone know if the K2CO3 can be subst'd with Na2CO3 in the NaEtSO4 -> NitroEthane workup?

2. Or if the 95% "everclear" style ethanol can be subst'd with 95%/5% methylated denatured alcohol? (...)

3. Or for that matter, if the NaNO2 can be subst'd with KNO2? (...)



Bio:

The increase in yield brought by the addition of alkaline carbonate, all equal things besides, is thus manifest. The use of a potassium salt gives a more fluid product, by lowering of the melting point eutectic and increase in solubility in water. For this reason probably, the yield obtained with potassium carbonate is higher than that which the sodium carbonate gives, with equal molecular concentration. Moreover, in the presence of CO3Na2 or of CO3K2, the reaction is less exothermic, therefore easier to . Finally the proportion of secondary products: methanol, méthylamine, HCN, are appreciably reduced.

A proportion of 2.5 mol of CO3K2 per 100 mol of NO2Na, is 5% in weight, appears to be most favorable.

This applies to EtNO2 also and the dry distillation of EtHSO4 & NaNO2is not the best yielding procedure due to scorching and heat transfer etc problems.



Roy g biv:

The method detailed above is from Chemical Abstracts Vol 49 pg 836.
Below is info which may be of some use to dreamers. Extract from the
Hive by moo (may he or she receive all the blessings of the universe)
in Methods Discourse.

"The bees know that the nitroethane preparation procedure from sodium
ethyl sulfate given in rhodium doesn't give the the results expected.....
... because of the very terse abstract posted in Chemical Abstracts....
The actual method from the article referenced is a bit different....."

The following was added in the original article by moo.

Preparation of Nitroethane
by Gerard Desseigne & Henri Giral

The reaction flask is charged with:
26.5 g (0.0625 * 3moles) of tech grade K2CO3 dissolved in 137 g of water
320 g of 97% tech sodium nitrite
6 ml of cetyl-oleic alcohol or oleic alcoholm(antifoaming agent)
Vol of the mixture is about 420 mls
The mixture is heated on a bath at 130C with stirring. The addition funnel
is charged with 750 ml of an aqueous solution of 444 g (3moles) sodium ethyl
sulfate. The solution is added to the reaction mixture during 50-60 mins at a
suitable rate to keep the reaction mixture at 125-130C, with vigorous
stirring.
The distillation of the nitroethane begins when the addition is started.
When addition of NaEtSO4 is complete 100 mls of water is added during 10 mins.

The distillate separates into 2 layers. Can be distilled at 760mmHg with a distillation column. Distillation starts at 30C. All below 74C is discarded. Temp should settle
at 87C & distillation is stopped at 99.8C.

Yield of nitroethane:96 g (1.28 moles), 42.6% based on NaEtSO4



I tried both the dry distillation and the one described above (solutions mixed). Got less than half a ml each time, but then again I started with 2g each of nitrite and Na-ethylsulfate.

72 grams of NaEtSO4 are sitting in my dessicator at this moment. Let's see how it goes next time. BTW the EtONO danger is new to me. Oh and the NaEtSO4 was made from sulfuric, everclear, lime and soda as is described in Rhodium's "nitroalkane preparation FAQ".

What I don't understand are the temps for distillation: Since when does nitroethane come over at 87C under one atm?

Drunkguy - 3-12-2006 at 07:01

Im interested to see if anybody can get a workable nitroethane synth. I have been searching online and it seems that people get all the hardware in check and then they never post their results.

Boomer - 4-12-2006 at 08:28

"... and then they never post their results."

You know why? THERE IS NOT WORKABLE NITROETHANE SYNTH!

Just joking, but it definitely does not work as stated by most online sources, and is not really OTC:

- Isomerisation of ethyl nitrite is a myth, or so I have heard.

- Going via ethyl bromide/iodide plus sodium nitrite takes ages, needs DMF as a solvent, and the DMSO substitute again does not work since it reacts (same source, forgot who, but was an old bee), neither does glycol. Don't ask if the phloroglucinol addition makes it go as planned, anyway making alkyl halides as a pre-pre-precursor is no longer funny.

- Dry heating of NaEtSO4+NaNO2 is said to give hardly any yield "due to scorching and heat transfer problems"

- Mixing of solutions (see my post above) yielded even less. I tried again with 12g ethyl sulfate and 8g nitrite and got three drops at most, which dissolved on washing.

- Oxidation of ethylamine with m-chloroperbenzoic acid / dimethyldioxirane? Not really OTC.

I have not tried diethylsulfate + nitrite yet, but my hopes are low.
The same goes for EtBr or EtI + silver nitrite. I know it should work better than the sodium salt, but apart from having to make the halide first: working with no light, dry ether, 48-hour reaction, vacuum ... sounds fun.

So far my best (hahaha) yield was 1ml EtNO2 from 12g NaEtSO4 and 8g NaNO2, by mortar'ing it well together with 500 mg Na2CO3, then heating in an oil bath for an hour at 140C (oil). I doubt K2CO3 will make much of a difference, but I might try next time. What I suspect to bring yield up more is a high-boilling solvent to prevent scorching, perhaps combined with urea.

If the next two steps have the same yield (17%), there will be 2 mmol nitropropene left, and from there 400 µmol phenylisopropylamine. Could as well drink a coffee :P
Or stick to explosives :cool:

[Edited on 4-12-2006 by Boomer]

bio2 - 4-12-2006 at 16:03

.........THERE IS NOT WORKABLE NITROETHANE SYNTH!.........

Huh? The 42.6% yield quoted above ain;t far off from the yiekd
just reported by one of our members.

solo - 4-12-2006 at 17:33

Reference Information



A New Method for the Synthesis of Aliphatic Nitro Compounds
NATHANK ORNBLUMHA, ROLD0. LARSONR, OBERTK . BLACKWOODDA, VIDD . MOOBERREYU, GENEP. OLIVETOA ND GALENE . GRAHAM
Journal of the American Chemical Society 1956, vol:78 iss:7 pg:1497


Abstract
A simple new synthesis of primary and secondary nitro compounds which involves treating alkyl halides with sodium nitrite in dimethylformamide is described; 55-62% yields of pure nitro compounds are obtained.

[Edited on 5-12-2006 by solo]

Attachment: A New Method for the Synthesis of Aliphatic Nitro Compounds1, 2.pdf (661kB)
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DeAdFX - 4-12-2006 at 17:57

Quote:
Originally posted by Boomer
snip

[Edited on 4-12-2006 by Boomer]


Would the use of a vacuum or larger amounts of reactants help give a higher yeild of nitro ethane? Or how about combing the synthesis of ethyl hydrogen sulfate with the sodium nitrite addition. This way the water that is formed from the bisulfate/EtOH reaction can dissolve the nitrite and NaEtSO4 and react to form Sodium sulfate and nitroethane. The Sodium sulfate well then form a hydrate with the water.

Filemon - 14-7-2007 at 15:07

Quote:
Originally posted by Boomer
There is an error in that method, read yourself (from one of the few good threads on WD):


Evil lurker:

Nitroethane, that substance which is so cheap at any chem supply house, but so damn hard to get. Making the stuff ain't very much easier than buying it from the recipes on the net.

The two OTC easiest ways, using sodium ethyl sulfate and diethyl sulfate as reagents are very hard and dangerous to manufacture. The problem lies in the water molecule the ETOH creates when it forms the ester. The apparatus looks plain scary to operate, and creates diethyl ether as a side product and the yields suck ass!

But now that problem has been fixed. Sodium ethyl sulfate can be easily prepared in the home laboratory from common sodium bisulfate found in pool pH down and 95% pure grain alcohol, and baking soda or sodium carbonate found in pH up.

113 parts by weight of sodium bisulfate and 20 parts by weight of pure grain alcohol are combined in a flask and brought to boiling upon which time the sodium bisulfate crystals disappear and sodium sulfate forms.

When the reaction has been completed, the flask was is immersed in an ice bath and vigorously stirred until the tempurature rapidly goes below 32.3C.

The formed sodium sulfate is thus filtered out leaving an anhydrous ethyl hydrogen sulfate/ethanol mix.

The excess ethanol is distilled off, and the ethyl hydrogen sulfate is neutralized with an appropriate quantity of sodium carbonate leaving sodium ethyl sulfate.

Simple... thats all there is to it! The secret to how it works is the excess sodium bisulfate when rapidly cooled below 32.3C forms the decahydrate, or Glaubers salt, and this sucks the water out of the reaction.

This is discussed futher in US Patent number 3,024,263.

Nitroethane can now be easily worked up according to this synth:

1.5 mole sodium nitrite (103.5g) is ... (here comes the synth you posted) ... Yield 46% of theory.



Why is it better? The sodium bisulfate decompose in the alcohol in sulfuric acid and sodium sulfate. The only reason is that the sodium sulfate is cheap than the concentrated sulfuric acid.

Why does the method that proposes rodhium use CaCO3? For remove the sulfuric acid without reacting?

[Edited on 14-7-2007 by Filemon]

Polverone - 21-2-2010 at 00:38

It's repeated in many sources that the reaction of sodium nitrite with alpha-bromo acids can produce nitroalkanes in about 50% yield, but the reaction is only useful for the lowest two of the series. Contrary to e.g. Vogel, the synthesis appears to work reasonably well up to 3-carbon nitroalkanes rather than only 2-carbon, at least according to Auger's original paper on the subject.

There's a brief translation of the nitroethane passage from Auger's paper in the Rhodium nitroethane synthesis compendium.

The original text:
Quote:
Acide α bromopropionique et azotite de sodium:— 20 gr. d'acide sont saturés par une solution à 20 0/0 de carbonate de potassium, en présence de phtaléine; on ajoute alors 20 gr. d'azotite de sodium, et le liquide formant environ 100 cc. est introduit dans un ballon à distiller de 250 cc., dont le tube adducteur est soudé très bas pour permettre une rapide distillation. Vers 100 cc. la réaction commence; on éloigne la flamme et continue la distillation après l'apaisement de la première réaction. Lorsqu'il ne passe plus de gouttes huileuses, on décante l'huile distillée, qu'on sèche sur le chlorure de calcium et rectifie. Rendement 50 0/0 de la théorie.


The Rhodium translation:
Quote:
Add 20g of the acid to a solution of K2CO3 in the amount of base that causes the solution to be basic to phenolphthalein. The add 20g of NaNO2--there should be approx. 100ml of solution. Place in a 250ml rb flask and distill quickly- the first 100ml will come over before the rxn takes place. Then the nitroethane comes over. Distill until no more product comes over.(don't distill to dryness)


The version I pieced together with machine translation and some slight knowledge of French:
Quote:
20 g of acid are saturated by a 20% solution of potassium carbonate in the presence of phenolphthalein, then 20 g of sodium nitrite, and the liquid forming about 100 cc. is introduced into a distillation flask of 250 cc., and the conducting tube is joined very low for a quick distillation. Around 100 cc. the reaction begins, we remove the flame and continue the distillation after the easing of the first reaction. When no more oily drops pass over, decant the oil distilled, dry over calcium chloride and rectify. Yield 50% of theory.


I am certainly missing some idiom, because even with the help of a French-English dictionary for chemists (thanks, S.C. Wack) I cannot satisfactorily interpret all of the directions in this passage. Or, rather, I think I understand what should be done, but it is in spite of (rather than because of) my ability to translate the French. I would appreciate it if a fluent French reader could see how the translations compare.

I did a complete OCR cleanup and translated it all using machine translation + the dictionary + the lingering memories from high school French classes. It was slow going, but at least it appears feasible to mostly-understand old procedures in foreign languages this way if an English translation has not already been published for my convenience.

Attachment: auger-nitroalkane.pdf (83kB)
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UnintentionalChaos - 21-2-2010 at 06:33

Injecting my marginally relevant experience here, but I have run the nitromethane synthesis from orgsyn exactly as stated except for a 50% scaledown and can report that it works with the reported 35% yield. You'll need to have a thermometer *in* the liquid because the reaction does indeed take off around 80C and self-heats for quite a while. This temperature might be a bit different for higher homologues and it probably will not self-distill as well.

Obviously, watch out when attempting to scale up due to the exotherm and gas release. I strongly suspect that the 50% yield quoted in the above paper is rather optimistic.

[Edited on 2-21-10 by UnintentionalChaos]

benzaldehyde or MeO2 analogue been lonely too long ?

Rosco Bodine - 14-11-2010 at 01:22

http://www.youtube.com/watch?v=5LxC3M-Yngs&fmt=18 Harry Nilsson - Put The Lime In The Coconut

http://www.youtube.com/watch?v=HpmJl0pdwyY&fmt=18 Lonely Too Long

http://www.youtube.com/watch?v=SBEomCtCujw&fmt=18
The Only Living Boy In New York

http://www.youtube.com/watch?v=sfv3kBzJZgU&fmt=18 One Trick Pony

http://www.youtube.com/watch?v=Rkgozdtsh_g&fmt=18 Groovin'

http://www.youtube.com/watch?v=WrwhfhncPfM&fmt=18 Beautiful Morning

http://www.youtube.com/watch?v=Hfhk2WxfV2c&fmt=18 People Got To Be Free

http://www.youtube.com/watch?v=o4fWN6VvgKQ&fmt=18 Get Together

Maybe these nitroethane related threads need merging or should be made into a compendium .....

Anyway not to be dismayed by disorganized channels of information , here is some supporting reference on the improving of yields gotten from the reaction of sodium ethylsulfate and sodium nitrite, by means of using sufficient water to help solublize and emulsify the reactants, with
the water including some sodium carbonate, or perhaps alternately sodium bicarbonate or sodium borate, to buffer
the pH of the reaction higher and oppose the byproduct formation of nitrous acid and ethyl nitrite which are undesired, raising the yield of nitroethane to 35% which
compares more favorably with the 65% yield by the alternative diethylsulfate and sodium nitrite reaction, which is also an emulsion reaction method. See article attached
Preparation of nitroethane, JCS 1944, 24-25.

A machine translation follows for the attached patent AT76500. Also attached is the Swiss issued parallel patent CH75523. These two patents appear to be equivalents of the original patent DE294755. The machine translation is not very clear, but is helpful.

Machine translation of AT76500
Method to the representation of nitromethane and its homologous one.
The method aims at one probably-files relative and technical light feasible representation method possible from nitromethane and its homologous one to to make, bodies, which can serve as valuable starting material for other chemical compounds, particularly for aliphatic amines. The method is based to bottom suitable conditions taking place action of approximate equivalent amounts of nitrous-acidic salts on that on alkyl-sulfur-acidic salts. This principle of the method is not in as much new as for the particular case of the action of sodium nitrite on ethyl-sulfur-acidic potassium already from that years 1878 a publication of L: : uterbach is present (reports of the German chemical society, Bd. 11, S. 1225).
This found, indicates Nitroäthan with the dry distillation of a mixture of the salts mentioned the bottom Reaktiocs products also however as yields for in many way to implemented experiments only amounts to 6% of the theory at Nitroäthan. Furthermore years have 1907 Prafulla Chandra Ray and Panchanan Neogi in (Proc. OF the chem. ones. Soc., Londen, Bd. 25, S. 259) a more general study over the action of Alkali-und alkaline-earth nitrites on various salts of the ethyl sulfuric acid published. It observed beside the known reaction products also the formation of small amounts of Nitrobutan. Experiments to the representation of other Nitroparaffine on the basis of the mentioned method do not seem to be made. It could not stress also the method for the representation of the Nitro of ethane practical interest, if it did not succeed to improve the yields whole significant.
It has itself now shown that one is by a changed operation, which forms the subject-matter of the invention indeed in the conditions, to bring the yields compared with the surprising high achieved of loud brook with Nitroäthan z. B. on approximately 35%, with nitromethane even on over 50% of the theory, against what they sink with higher homologous ones however. If one dampens the fine mixture of nitrite and alkyl-sulfur-acidic salt with as much water that with gentle heating, with approximately 50 to 600, an aqueous thin, milky liquid develops, then something already occurs a reaction over 100 ', so that with that water vapors much Nitroveibindung iiberdestilliert. By the liquefaction of the salt mixture will the reaction between the two salts obviously significant facilitated, now however whole particularly intimate mixed residue become from that finally drying can then still other amounts of the Nttrokörpens by somewhat stronger egg hitzen to be driven out.
The water additive alone is however still no sufficient prerequisite to the achievement of bestmöglichster yields. The alkylschwefelsaurel1 of salts decomposes with presence of little water, thus in concentrated solution. with the heating light bottom formation of free sulfuric acid and/or. acidic sulfates and, once more acidic become, this decomposition of the salt continues to walk then very rapid. Thus once the amount at alkyl-sulfur-acidic salt reduced, necessary for the reaction, becomes and then makes the formed sulfuric acid from the nitrite salpetjige acidic ones free, those, like known formation of Nitrosäuren responsive, bottom in the Entstehungszustacd with primary Nitro paraffins. Both procedures decrease thus. the yield at Xitroparaffinen. If one prevents therefore of the reaction mixture, an other increase of the yield occurs. This effect becomes now actual achieved by addition of a suitable alkali. Corroding alkalis are however not particularly suitable. probably however alkaline responsive salts very much weak acids, like Kaliumkabonat, sodium carbonate, borax and similar salts, with those a release of this weak acid no formation of nitrous acid caused. One will thus dampen the mixture of the salts mentioned by alkyl-sulfur-acidic salt and nitrite not with pure water, but with a solution of soda or another. Already relatively small amounts at alkali are sufficient, in order to ensure a permanent alkaline reaction of the salt mixture with the distillation.
An unnecessary large excess at alkali is to be avoided natural. Used one sodium carbonate. like that 5 to 7% is theoretical sulfuric acid complete sufficient contained by the weight the salt alkyl-sulfur-acidic in that.
It is easily apparent that the alkali additive plays whole other roller here. as with methods likewise working with alkali rzur representation of nitromethane by KnnMrkuug of C'hloressigsäure on nitrite. With this method the alkali serves only for it.
EMI1.1
<Desc/Clms PAGE NUMBER 2>
Amounts at alkali used and are these the Zersetzlichkeit of the alkyl-sulfur-acidic salts impairing the yield at Nitroalkyl by waters if possible preventing.
EMI2.1
to against 20 (y to rise leave. The distillate separates into an aqueous and an oily layer.
The latter consists to a large extent of Nitroäthan, which swims however due to a content at specific lighter compounds, acetaldehyde and ethyl nitrite, but ordinary on the water. Also this contains acetaldehyde. The pure representation of the Nitroäthans squinted then more other after known methods. With the fractionation can become all between 1060 and 1150 turning into as pure Nitroäthan considered. Small amounts of a dark remain
EMI2.2

In whole similar manner one proceeds with the preparation of nitromethane and nitropropane. With the representation of the first insignificant amounts of ISO nitrile do not arise, which give one to the escaping gases (Metbylnitrit) as well as the crude nitromethane much unpleasant odor. The elimination of the ISO nitrile offers however no difficulties.
The here described method is substantial various of the known method from Walden to the representation of nitromethane by action of dimethyl sulfate on Kaliumnitrit with presence of water (reports of the German chem. Society, 40 (1907). S. 3216).
This reaction runs after Walden in the cold in the sense of the equation
EMI2.3
and to Waiden as yield nitromethane receives 50 to 57% of the amount calculated from this. Here thus only a methyl group changes into the approximate same yield as with the method after present invention in nitromethane. Walden turns thereby still another large excess
EMI2.4
CSU it would have again plentiful amounts old nitromethane obtained after the method of the present invention. Obviously he did not foresee the possibility of such a reaction.
Also the water additive plays a various roller with the two methods. With the method after Waiden the water is once the violence of the action of dimethyl sulfate on dry nitrite moderate, furthermore by the reaction the formed, methyl sulfur
EMI2.5
PATENT CLAIMS:
1. Method to the representation of nitromethane and its homologous one by action of nitrous-acidic on alkyl-sulfur-acidic salts, characterised in that one the salt mixture as much water adds that with gentle heating liquefaction of the mass milchigejt to a aqueous-thin, liquid occurs.

Attachment: CH75523 Nitroethane.pdf (143kB)
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Attachment: AT76500 Nitroethane.pdf (256kB)
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Attachment: DE294755 Nitroethane.pdf (185kB)
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Attachment: Preparation of nitroethane JCS, 1944, 24-25 .pdf (381kB)
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[Edited on 14-11-2010 by Rosco Bodine]

AndersHoveland - 29-7-2011 at 16:29

Catalytic nitration of alkanes with nitric acid was first successfully achieved by the use of N-hydroxyphthalimide (NHPI) under mild conditions; the key to the present nitration was found to be the in situ generation of NO2 and phthalimide N-oxyl radical by the reaction of NHPI with nitric acid.


http://pubs.rsc.org/en/content/articlelanding/2001/cc/b10237...
Sounds very interesting, and potentially useful.

Bitburger - 29-7-2011 at 22:42

Quote: Originally posted by chemoleo  
I was wondering, not for the first time, which general methods are available for the production of simple nitro alkanes.

I can see two routes for this:

1) R3C-NH2 --> oxidise --> R3C-NO2.

2) R3C-Cl/Br/I + NO2- --> R3C-NO2 + Cl/Br/I-

where R is H or whatever.

I know that both reactions have been shown to work, but particularly in the latter case I failed to find references as to what conditions exactly need to be employed.
For instance, tetranitromethane can be made by the reaction of iodopicrin I3CNO2 with AgNO2. What reaction conditions are supposed to be employed there? I.e. iodopicrin is surely insoluble in water, so to facilitate the reaction with silver nitrite would be tricky. Equally, how about the reaction of chloroform with AgNO2? The former is definitely not soluble, so how can one go about to get the reaction to work?
Alternatively, how about chlorination of ethylene to form 1,2 dichloroethane... and to react this with AgNO2.
I take it the reason why the Ag, rather than the Na/K nitrite is chosen is because the former is highly insoluble, thus shifting the equilibrium of the reaction faster to the right.

As to reaction scheme 1) - the oxidation of amines - what are the generic conditions there? I.e. what if the starting compound was ethylenediamine H2N-CH2CH2-NH2? It's a liquid, soluble in H2O and highly basic.

Any help on this would be appreciated.:)


[Edited on 21-11-2006 by chemoleo]


Your answers are still unsolved after 7years!

I know that AgNO2+iodoethane in ether works but it takes nearly 40 hours under reflux and the yields where small. Though the inventor Victor Meyer did this reaction with continious stirring in the cold.

A byproduct is formed the (oxy)nitrosoethane (ethyl nitrite) which isn't a nitrite ester in mechanistic way, rather a arises from a substitution reaction.

Note that ONO is an ambident nucleophile, where you get the unwanted byproduct if the more electronegative oxygen is attacking. But I think that the weak bond of Ag with oxygen, the bond that get formed with an ether between the small(!)Ag ion and the oxygen of the ether serves as stabilizing effect - like in Grignard reactions. The reaction is best done by low temperatures to prevent ionisation of one of the oxygen atoms in ONO. On the cold, the lone pare on the nitrogen can attack with the slightly positive carbon of your haloalkane.

In the other cases a aprotic, polar solvent is used. These have the tendency to make te lone pair on the N even more reactive. Meanwhile, the positive charge of the sodium decreases so far that you don't have to be scared to get ionisation and thus attacking of the oxygen on ONO. What probably happens is that in that case the negative charge is spreading out over the 2 oxygen atoms of ONO and thus the neg. charge is delocalised, making the lone pair on the nitrogen even a better nucleophile.

Again, do this reaction in the cold, with stirring and in the last case it is better to simulate the reaction time, the shorter - the better. since nitroethane is volatile. Only solvent extraction with low boiling peth works to isolate your nitroalkane.

ID of nitroalkanes could easy be done by adding NaOH to nitroalkanes and then yellow crystals are formed. Decomposion of this with conc. H2SO4 gives in the case of nitroethane the odour of acetaldehyde. Nitroethane has a pleasant smell of marzipan, but formes an azeotropic mixture with water!


where did you find the following route?:

1) R3C-NH2 --> oxidise --> R3C-NO2

Have some members tried it?

thebishop - 2-3-2013 at 11:35

Hi there! I want to synthesize nitroethane using one of the schemes described here, but i'm a bit confused about the methods. I was wondering if someone could give me a hand?

Firstly, I want to start with sodium ethyl sulfate. This will be synthesized either by reacting sulfuric acid with ethanol, or sodium bisulfate and ethanol, as described by Boomer. Now, NaEtSO4 is a solid, yet no mention is made in either of the NaEtSO4 synthesis methods about how to recrystallize the compound.

I've seen some methods of synthesizing NaEtSO4 from H2SO4 and EtOH by heating under reflux, and some (wikipedia ethyl sulfate) say that the temp of the exothermic reaction must be kept below 170oC to prevent the NaEtSO4 decomposing back to H2SO4. I'm not sure where to go here ... whichever way I go I would then add Na2CO3, filter off the carbonate salt and then gently boil off the water to leave the NaEtSO4 salt. How does that sound?

Moving onto the sodium bisulfate method, Boomer quote Evil lurker who says:

"The formed sodium sulfate is thus filtered out leaving an anhydrous ethyl hydrogen sulfate/ethanol mix.

The excess ethanol is distilled off, and the ethyl hydrogen sulfate is neutralized with an appropriate quantity of sodium carbonate leaving sodium ethyl sulfate."

Well leaving the sodium ethyl sulfate in what? If it is anhydrous, and the ethanol has been boiled off, what is it dissolved in?

I will then react the NaEtSO4 and NaNO3 by dry distillation to try and produce nitroethane. The yields seem to vary depending on who you ask, but i'm going to give it a go. I assume that the two solids are mixed with stirring and heat, and that a vapor is produced which condenses in the distillation apparatus?

[Edited on 2-3-2013 by thebishop]

AndersHoveland - 5-3-2013 at 02:21

If any of you can obtain some N-hydroxyphthalimide, you should be able to get nitric acid to react with methane/ethane/propane at room temperature. The N-hydroxyphthalimide acts as a catalyst, so you only need a very small ammount. It procedes through a radical mechanism.

"Nitration of alkanes with nitric acid catalyzed by N-hydroxyphthalimide", Shinji Isozaki, Yoshiki Nishiwaki, Satoshi Sakaguchi, Yasutaka Ishii, Chem. Commun., Issue 15, 2001, 1352-1353


If you think about it, if just the NHPI is mixed with nitric acid, there should be an equilibrium of radicals simultaneously forming and reacting.
It is not all that unbelievable that radicals can exist in equilibrium. It is well known in solutions of NO2 in water (as there is a tiny equilibrium with HNO3 and nitric oxide, a radical itself).

And I am sure the aromatic ring on the NHPI must be nitrated to some extent in nitric acid, but that is really not of any importance here.

The sturcture of NHPI is
H4C6(C=O)2NOH

you can easily see how the hydroxylamine group would get oxidized by the nitric acid to a radical =N-O•

It is not just nitric acid that can be used. "Modern Oxidation Methods", by Jan-Erling Bäckvall, mentions that in the presence of NPHI, NO2 can be used to nitrate cyclohexane, with a 70% yield under air (apparently the presence of oxygen improves the yields), 70 °C, reaction time 14 hours.

[Edited on 6-3-2013 by AndersHoveland]

Nicodem - 5-3-2013 at 08:50

And where do you have the reference?

Metacelsus - 5-3-2013 at 11:13

What about electrolytic oxidation? There's a book in the ScienceMadness library that I read a few weeks ago that mentioned electrolyzing aniline to nitrobenzene (which might apply to other amines), but sadly whenever I try to access it (or any other book in the library) I get error 404.

Formatik - 5-3-2013 at 17:53

Quote: Originally posted by thebishop  
I will then react the NaEtSO4 and NaNO3 by dry distillation to try and produce nitroethane. The yields seem to vary depending on who you ask, but i'm going to give it a go.


This won't make any nitroethane; and it is likely to blow up for reasons mentioned here.
Quote: Originally posted by AndersHoveland  
If any of you can obtain some N-hydroxyphthalimide, you should be able to get nitric acid to react with methane/ethane/propane at room temperature.


The reaction is not at room temperature (60 C) and it's done under argon (one example was under air) for 15 hours, though the original reference basically only showed this to work in cycloalkanes, and one longer chain alkane. The reference is below.

Attachment: b102374h.pdf (55kB)
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[Edited on 6-3-2013 by Formatik]

zed - 5-3-2013 at 19:57

Well ethylene is widely available. Might be able to produce it cheaply by pyrolysis of HDPE.

Addition of HNO2, across the double-bond might work in some universe.

AndersHoveland - 5-3-2013 at 22:36

Quote: Originally posted by Formatik  

The reaction is not at room temperature (60 C), though the original reference basically only showed this to work in cycloalkanes, and one longer chain alkane.

I really do not think it matters too much. The reaction is very versatile.

Here is an informative link:
http://www.tandfonline.com/doi/pdf/10.1080/01614940902743841
Quote: Originally posted by zed  
Well ethylene is widely available. Addition of HNO2, across the double-bond might work in some universe.

We know that nitrogen dioxide can react with ethylene under ambient conditions to form 1,2-dinitroethane. It procedes through a radical mechanism. (if there is any air some mixed nitrate esters also form)

Perhaps if the reaction was done in solution in the presence of Fe+2 ions. Using an excess of ethylene in solution, and slowly pass NO2 in, while also periodically making small additions of an Fe+2 compound in intervals.

Normally ferrous salts reduce NO2 to NO, but if some other inert solvent (besides water) was used I would imagine that FeNO2+2 would form. I do not know, but possibly if this substance was heated in the presence of ethylene. Many nitrites tend to be rather unstable; solutions of ammonium nitrite, for example, decompose even before the boiling point of water is reached.

The radical •CH2-CH2NO2 would probably tautomerize to •CH2-CH=NO2-, and would be able to immediately oxidize the Fe+2 ion (also in the presence of two hydrogen ions) to finally form nitroethane.

Just an idea.

[Edited on 6-3-2013 by AndersHoveland]

Nicodem - 6-3-2013 at 07:24

Quote: Originally posted by AndersHoveland  
The reaction is very versatile.

Only if the substrate is within its scope. Methane and ethane do not appear as such since neither has a reactive methine, methylene or benzylic group that could be subjected to N-hydroxyphthalimide catalyzed nitration. It is apparent from the examples and the reaction regioselectivity, as described in that article, that methyl groups do not undergo the reaction. That is something one can infer also from the proposed reaction mechanism.

zed - 6-3-2013 at 18:45

That being said, what are the possibilities of producing Nitroethane, via Ethylene?
I haven't seen any literature on the topic, but it does seem like it might be possible.

[Edited on 7-3-2013 by zed]

[Edited on 7-3-2013 by zed]

AndersHoveland - 6-3-2013 at 20:42

Quote: Originally posted by Nicodem  

Only if the substrate is within its scope. Methane and ethane do not appear as such since neither has a reactive methylene group

You really think that a methyl group would be less reactive than a methylene group?! Please show me just one other example in organic chemistry where this is the case (where it is only bonded to other carbon atoms). Ethane is an alkane just like propane or cyclohexane.

[Edited on 7-3-2013 by AndersHoveland]

Formatik - 6-3-2013 at 23:05

N-hydroxyphthalimide catalysis: the first paper mentioned about this wasn't clear which substrates would work. But, looking here: http://dx.doi.org/10.1021/jo025632d it apparently does work for lighter alkanes (CH3CH3, CH3CH2CH3), though at higher temperatures (100 C for 14 hrs, working at 50 C produced a miserable yield (6%) i.e. in nitropropane).

This would all need an autoclave of course.


The older literature mentions ethylene nitrite C2H4(NO2)2, alongside a volatile poisonous oil, being formed from passing ethylene into liquid N2O4, or heating the two gases (Dictionary of Chemistry by H. Watts).

Nitroethane from 2-Bromoproprionic acid

anomolous - 17-3-2013 at 17:16

I'm not sure if I should have started a new thread or not. If so, I apologize.

Of the many syntheses of nitroethane discussed in this thread, one method in particular sparked my interest. UpNatom, in his posts above, mentioned the method described in US patent 4,319,059, using 2-Bromoproprionic acid, Rhodium started a thread about this patent on the Hive too. The patent describes a straightforward reaction of 2-bromoproprionic acid with an alkali nitrite and magnesium ion (methoxide is preferred but the sulfate, chloride, etc. are also said to work) in DMSO. Since 2-bromoproprionic acid can be made from alanine using HBr and sodium nitrite, I thought I'd give it a try. Here are the results:

Experimental 1: 85 g of magnesium sulfate was added to 200 mL of DMSO and heated on a hot-water bath to help the MgSO4 dissolve, which was a waste of time because hardly any dissolved. 50 g of 2-bromoproprionic acid was poured into the flask and swirled as magnetic stirring didn't work. An attempt was made to dissolve 28 g of sodium nitrite in DMSO but it didn't dissolve well either. Maybe more time was needed. The sodium nitrite/DMSO mixture was poured into the flask quickly resulting in a slightly exothermic reaction. It may be better to add the NaNO2 as powder in increments. The flask was stoppered and manually shaken once in awhile over about 5 hours. The pressure was released by removing the stopper occassionally. It popped out a few times. Mechanical stirring and a reflux column would be better for this reaction. I ended up allowing the mixture to sit overnight, which isn't a problem according to the patent. In the morning the mixture was poured into a 1000 mL sep funnel, filtering the still undissolved magnesium sulfate, added a couple of splashes of 14 HCl and nearly filled the remaining space in the sep funnel with water. I extracted this mixture with DCM (4 x 100 mL), washed the extracts with brine, and dried over MgSO4, before removing the DCM by vacuum. The residue consisted of what appeared to be stinky, hot DMSO. No nitroethane was recovered.

Experimental 2: 430 mL of DMSO was poured into a 2000 mL two-neck flask equipped with mech. stirring and a reflux column. The column was removed while making the additions. 30 g of magnesium methoxide was added and stirred for 30 min. 50 g of 2-bromoproprionic acid was poured into the flask and allowed to stir for 15 min. before adding 25 g of sodium nitrite in 5 g increments over an hour. The mixture was stirred at room temperature for 5 hours. 600 mL of 10% HCl was added carefully to neutralize the reaction; this was stirred for 30 min. Extraction with DCM (4 x 100 mL). I skiipped washing the extracts and went straight to distillation, removing the DCM and then vacuum distilling the stinky residue. No nitroethane was collected.

I can smell a sweet smell that I assume is nitroethane after the reaction is complete. The water layer smelled more like nitroethane than the DCM extract. It doesn't appear that the nitroethane is going into the DCM layer but I'm not entirely sure there is nitroethane. My wife ended up dumping the aqueous layer down the drain. This is my first attempt to use DMSO and I must tell you, it stinks.

Any help would be appreciated.

AndersHoveland - 18-3-2013 at 23:56

Quote: Originally posted by anomolous  
Of the many syntheses of nitroethane discussed in this thread, one method in particular sparked my interest. UpNatom, in his posts above, mentioned the method described in US patent 4,319,059, using 2-Bromoproprionic acid, Rhodium started a thread about this patent on the Hive too. The patent describes a straightforward reaction of 2-bromoproprionic acid with an alkali nitrite and magnesium ion (methoxide is preferred but the sulfate, chloride, etc. are also said to work) in DMSO. Since 2-bromoproprionic acid can be made from alanine using HBr and sodium nitrite, I thought I'd give it a try.


What if you did this reaction on glutamic acid (from the common food additive MSG) ? Presumably you could get 4-nitro-butyric acid.
NO2-CH2CH2CH2-COOH

Now, does anyone remember the thread about making nitromethane from 2-chloroacetic acid? I am not going to go into the details, but will quickly summarize.

One of the possible ways to chlorinate acetic acid is to dissolve it in acetic anhydride and pass chlorine into the solution. Under the extremely acidic conditions, acetic acid essentially reverts to its CH2=C(OH)2 tautomer, through which it can be attacked by the chlorine.

Presumably, we could selectively chlorinate 4-nitro-butyric acid under the same conditions to get 2-chloro-4-nitro-butyric acid.
NO2-CH2-CH2-CHCl-COOH

Nitromethane can be made by distilling 2-chloroacetic acid with sodium nitrite. So what would happen if we distilled 4-nitro-butyric acid with sodium nitrite? Is it possible that 1,3-dinitropropane could result?
NO2-CH2-CH2-CH2-NO2

The thing about this compound is that the nitro groups are not vicinal, so the compound would not display thermal instability. (it would not be a good idea to try to distill 1,2-dinitroethane for example)

[Edited on 19-3-2013 by AndersHoveland]

anomolous - 20-3-2013 at 22:44

The reason I was attracted to this route was its apparent simplicity. I may try vacuum distilling instead of extracting with a solvent. But I don't understand why a solvent extraction wont work? Has anyone dealt with DMSO before? It seems to have strange characteristics. Is there something I'm missing? Do you think vacuum distillation is the answer or is there some other method of extracting the nitroethane you'd recommend?

Another method using 2-bromoproprionic acid was mentioned on the Rhodium archive. Nitroethane Synthesis: A Compilation, method 7. It is the destructive distillation of 2-bromoproprionic acid. It occurs in a solution of K2CO3 with NaNO2. Follows is the reference: V. Auger. Bull Soc. Chim. France Post no 3,23,333 (1900). If you can find it please share. Though the yields are so-so (50%) I may give this method a try. But the patent method still haunts me.

anomolous - 24-3-2013 at 08:18

Another semi-failed attempt:

10 g magnesium methoxide in 50 mL of DMSO, followed by 17 g 2-bromoproprionic acid. 9 g NaNO2 dissolved in 65 ml DMSO added dropwise then stirred for 12 hours. Neutralized with 15 mL of 31% HCl. Vacuum distilled collected about 15 mL of liquid. Scent of DMSO present and faint fruity scent present. Added about 25 mL of water then extracted with DCM (2 x 10 mL). The DCM evaporated leaving a few grams of nitroethane ( I think).

Questions: How can I test for nitroethane? Do you think the 2-bromoproprionic acid should be pure? Would ether be a better solvent? Why is no one interested in this reaction?

S.C. Wack - 24-3-2013 at 10:45

Quote: Originally posted by anomolous  
If you can find it please share.


This thread?

madscientist - 26-3-2013 at 19:03

Quote: Originally posted by AndersHoveland  
Quote: Originally posted by anomolous  
Of the many syntheses of nitroethane discussed in this thread, one method in particular sparked my interest. UpNatom, in his posts above, mentioned the method described in US patent 4,319,059, using 2-Bromoproprionic acid, Rhodium started a thread about this patent on the Hive too. The patent describes a straightforward reaction of 2-bromoproprionic acid with an alkali nitrite and magnesium ion (methoxide is preferred but the sulfate, chloride, etc. are also said to work) in DMSO. Since 2-bromoproprionic acid can be made from alanine using HBr and sodium nitrite, I thought I'd give it a try.


What if you did this reaction on glutamic acid (from the common food additive MSG) ? Presumably you could get 4-nitro-butyric acid.
NO2-CH2CH2CH2-COOH

Now, does anyone remember the thread about making nitromethane from 2-chloroacetic acid? I am not going to go into the details, but will quickly summarize.

One of the possible ways to chlorinate acetic acid is to dissolve it in acetic anhydride and pass chlorine into the solution. Under the extremely acidic conditions, acetic acid essentially reverts to its CH2=C(OH)2 tautomer, through which it can be attacked by the chlorine.

Presumably, we could selectively chlorinate 4-nitro-butyric acid under the same conditions to get 2-chloro-4-nitro-butyric acid.
NO2-CH2-CH2-CHCl-COOH

Nitromethane can be made by distilling 2-chloroacetic acid with sodium nitrite. So what would happen if we distilled 4-nitro-butyric acid with sodium nitrite? Is it possible that 1,3-dinitropropane could result?
NO2-CH2-CH2-CH2-NO2

The thing about this compound is that the nitro groups are not vicinal, so the compound would not display thermal instability. (it would not be a good idea to try to distill 1,2-dinitroethane for example)


How are you going to make 4-nitrobutyric acid from glutamic acid?

Acetic acid and acetic anhydride are not what I would consider "extremely acidic" conditions. You have the mechanism wrong.

You don't know that you can selectively chlorinate 4-nitrobutyric acid at the 2 position. You're just guessing.

http://pubs.acs.org/doi/abs/10.1021/ja01170a039

How do you know that 1,3-dinitropropane is thermally stable enough to distill at any pressure up to 760mm Hg? (Implied by your failure to specify reduced pressure.) You don't, and again, you're guessing. What if you're wrong, and someone tries to distill it and it detonates? What then? Has it ever occurred to you that what you post could kill someone?
Quote:
You really think that a methyl group would be less reactive than a methylene group?! Please show me just one other example in organic chemistry where this is the case (where it is only bonded to other carbon atoms). Ethane is an alkane just like propane or cyclohexane.


Organic chemistry is full of subtlety. Carbon substituted aliphatic carbons are activated compared to unsubstituted ones. For example, look at the rate of peroxide formation with isopropylbenzene vs. ethylbenzene. You cannot just assume that what will work on one system will work on an apparently similar one, as it often will not.

You need to spend much more time studying fundamentals and a lot less scurrying from one random paper to the next, accumulating vast tomes of information that is ultimately useless to you as you are unable to integrate it. Some time spent with March's Advanced Organic Chemistry, and Physical Organic Chemistry by Anslyn and Dougherty, would do you a lot of good.

[Edited on 27-3-2013 by madscientist]

madscientist - 27-3-2013 at 09:29

Quote:
How are you going to make 4-nitrobutyric acid from glutamic acid?


I should clarify that I understand your plan is to swap out the amino group for a bromo and then a nitro, and decarboxylate. But how are you going to isolate it? I assume chromatography is out. That doesn't leave you with a lot of good options.

Impurities are like a plague, they multiply exponentially every time you carry a crude over to the next step. One pot procedures require careful consideration to develop.

The workup is usually half the battle, and sometimes a synthetic pathway will be deemed unfeasible due to a single difficult isolation. Practicality is something you need to be thinking about more often than never.

anomolous - 27-3-2013 at 15:19

Destructive Distillation of 2-bromoproprionic acid

120 mL of K2CO3 sol. (pH 11) was poured into a 500 mL flask, followed by 40 g of crude 2-bromoproprionic acid. Then 40 g of NaNO2 was added carefully in 5 g increments. After the NaNO2 had dissolved the reaction flask was placed into a preheated oil-bath (145C) and the distillation begun. The distillate separated into two layers with nitroethane on the bottom. The nitroethane was extracted with ether and ether removed via distillation, yielding 16 g nitroethane.

anomolous - 30-3-2013 at 21:04

I tried the reaction of 2-bromoproprionic acid with sodium nitrite in DMSO again. This time I vacuum distilled the resulting mixture yielding only a tiny bit of nitroethane. Is this patent bogus? I've gotten better results with the destructive distillation of 2-bromoproprionic acid. Bummer. Feel free to chim in if you learn anything new.

AndersHoveland - 31-3-2013 at 19:43

Also to correct a mistake, obviously I meant 2-chloro-4-nitro-butyric acid being distilled with sodium nitrite.
Quote: Originally posted by madscientist  
You don't know that you can selectively chlorinate 4-nitrobutyric acid at the 2 position. You're just guessing.

Do a search using the words "α-chlorination of carboxylic acids".
Quote: Originally posted by madscientist  

http://pubs.acs.org/doi/abs/10.1021/ja01170a039

How do you know that 1,3-dinitropropane is thermally stable enough to distill at any pressure up to 760mm Hg? (Implied by your failure to specify reduced pressure.) You don't, and again, you're guessing. What if you're wrong, and someone tries to distill it and it detonates? What then? Has it ever occurred to you that what you post could kill someone?

I think you are just getting outrageous here. I cannot imagine it is any more dangerous than nitromethane. If you think about it, it is just two nitromethanes bonded to a methylene group. Even your link mentioned nothing about any explosion danger. Just to allay any misplaced fears, a quick search revealed the boiling boint of 1,3-dinitropropane is 263.6 °C at 760 mmHg. Distillation is probably not even a practical option. Separation should still be simple enough since it is oil soluble and would likely separate out by itself.
Quote: Originally posted by madscientist  
Carbon substituted aliphatic carbons are activated compared to unsubstituted ones. For example, look at the rate of peroxide formation with isopropylbenzene vs. ethylbenzene.

Okay, yes I know. But that is a carbon bonded to three other carbons and only one hydrogen. I do not suppose you know of any examples where a carbon with two hydrogens and two carbons is more reactive? The example you described is only more reactive because the lone C-H bond is so much more polar.
Quote: Originally posted by madscientist  
But how are you going to isolate it? I assume chromatography is out. That doesn't leave you with a lot of good options.

Impurities are like a plague, they multiply exponentially every time you carry a crude over to the next step.

Your objections are noted. The only potential troublesome impurity that I can foresee would be secondary amines left after the initial diazotization/bromination steps.

I realize my proposal is a long route, but for amateur chemists it still might be easier than any of the alternatives. 1,3-dinitropropane is not an easy compound to synthesize from common chemicals.

[Edited on 1-4-2013 by AndersHoveland]

madscientist - 1-4-2013 at 08:10

http://msdssearch.dow.com/PublishedLiteratureDOWCOM/dh_07c8/...
Quote:
Elevated temperatures can also increase ease of detonation; do not distill nitromethane.


Nitromethane boils around 100C. If 1,3-dinitropropane boils at 260C (what's the source of this data?), then that is incomparably more dangerous. And what you're failing to understand - more proof you have no actual lab experience - is that boiling points can be determined even if something decomposes or poses a detonation hazard at those temperatures.

Quote:
Distillation is probably not even a practical option.


You say that now. But you previously implied otherwise:
Quote:
The thing about this compound is that the nitro groups are not vicinal, so the compound would not display thermal instability. (it would not be a good idea to try to distill 1,2-dinitroethane for example)


More wisdom:
Quote:
I think you are just getting outrageous here. I cannot imagine it is any more dangerous than nitromethane. If you think about it, it is just two nitromethanes bonded to a methylene group.


Yes, and by this same logic, there's no reason why the hazards of methyl nitrate, ethylene glycol dinitrate, and nitroglycerine would differ in any way. Long story short, you are guessing as always - assuming that things are as simple as you want to believe they are, and that the results will be as you hope they are.

Quote:
Even your link mentioned nothing about any explosion danger.


Journal articles usually don't mention the hazards of the chemicals they're working with unless they are truly exceptional. They assume that their readers aren't stupid enough to heat an explosive to 260C and let it bump away in a giant RB flask for an hour or two. Perhaps they are mistaken.

Quote:
Okay, yes I know. But that is a carbon bonded to three other carbons and only one hydrogen. I do not suppose you know of any examples where a carbon with two hydrogens and two carbons is more reactive? The example you described is only more reactive because the lone C-H bond is so much more polar.


The yields of 1-bromopropane and 2-bromopropane are not the same. At 150°, the relative yield
of 1-bromopropane is 8% of the monobrominated products, while 2-bromopropane has a 92%
relative yield. This result is surprising since if all H's on propane were equally reactive to Br.,
the relative yield of1-bromopropane should be 75%, and that of 2-bromopropane should be 25%.

Source: http://web.chem.ucsb.edu/~neuman/orgchembyneuman.book/11%20R...

This means bromination of a methylene in this system is nearly 40x faster than that of a methyl. There's a big difference and your insistence to the contrary really is just proof that you have zero credibility.
Quote:
Do a search using the words "α-chlorination of carboxylic acids".


I know about the Hell-Volhard-Felinskii reaction. Here's the problem:

Juvell has studied the velocity of bromination and chlorination of nitromethane, mono- and di-bromonitromethane and secondary nitropropane in 1N hydrogen halide. He finds that the reaction is always of the first order with respect to the nitrocompound. The velocities of bromination and chlorination are the same, and the concentration of the halogen is without influence. Consequently, it must be assumed that the velocity is determined by the unimolecular rearrangement of the nitrocompound to the aci-form, which takes up halogen instantaneously.

Source: http://www.sdu.dk/media/bibpdf/Bind%2010-19%5CBind%5Cmfm-12-...

When you are considering a new synthesis, you have to look at every possible route that the chemistry could take, not just the one you want to happen. And you need to prove, not hope, that these other routes won't predominate, or do a small scale test in the lab to find out (small means under 100mg, bigger than that and unexpected results could become major hazards).

Your post in another thread, advising people to run a SO<sub>3</sub> reaction in CCl<sub>4</sub> was evidence of your incompetence or laziness in this regard, and could have (and perhaps already has) cost lives, as this is, after all, how the Italians made their phosgene in WWI.

Quote:
The only potential troublesome impurity that I can foresee...


Your foresight is not of any value, you have zero credibility whatsoever, you've mostly just cluttered up the forum with bad (often lethal) advice, and speculation with no references, or references that do not back up your point. It would be much preferred if you were to simply keep your great ideas to yourself for now.

Nicodem - 1-4-2013 at 11:25

Quote: Originally posted by AndersHoveland  
The only potential troublesome impurity that I can foresee would be secondary amines left after the initial diazotization/bromination steps.

I generally don't have the time and patience to deal with the immense stupidity that Anders spams all over the forum and can only admire madscientist's efforts, but this sentence sounds like a chemistry April's fool joke. No chemist with a minimum of synthesis experience would be so narrow sighted to ever say something so chemically oxymoronic.

Anders, you will never be able to understand why your ideas are the result of incompetence, because for being able to comprehend that, you would need at least some competence, which you clearly don't have any. Your recent signature is clear evidence of this disability of which you would be the first victim, if you would ever become honest: "I'm not saying let's go kill all the stupid people...I'm just saying lets remove all the warning labels and let the problem sort itself out."

anomolous - 2-4-2013 at 11:37

So this is how information gets buried under tons of misinformation and unrelated dialog. Does anyone want to comment on my post? I didn't think so.

anomolous - 2-4-2013 at 11:40

Experimental 1: 300 mL of 96% H2SO4 was carefully added to 600 mL of ~95% ethyl alcohol in a 1000 mL Erlenmeyer. 250 g of anhy. NaSO4 was added and the mixture placed into the fridge and then into the freezer to cool to about 10C. The hydrated sodium sulfate was filtered leaving ~800 mL of ethylsulfate/alcohol solution . The solution was treated with sodium carbonate until a neutral pH of 7 was reached. Blue indicator paper turned slightly pink and red paper turned slightly blue at this pH. The neutral solution was cooled to near 0C and the precipated salt (mostly sodium sulfate) was filtered. The filtered solution was distilled and about 200 mL of alcohol was collected. The residue was filtered again and evaporated in a pyrex dish until a skin began to form, at which time the heat was turned off and the solution allowed to cool on the hotplate. A lot of salt, consisting of a mixture of sodium sulfate, carbonate, and ethyl sulfate, precipitated. This salt was saved to be analyzed and possibly used to produce more nitroethane. The filtered liquid, about 292g/240 mL, and a density of 1.21 g/mL was further distilled and more salts filtered yielding 210 g/155 mL (= Density of 1.35 g/mL). This close to the density of a 50-55% solution of ethyl sulfate, according to the Antonch and Desseigne figures. Upon sitting further, overnight, the solution crystalized further, leaving 164 g/123 mL (Density = 1.33) of sodium ethylsulfate sol. A 55% (by weight) solution of 210 g ethylsulfate sulfate sol. would contain 210 g * .55 = 115.5 g. The molar mass of ethyl sulfate is 148.12, which means we hypothetically had about 0.77 moles of ethyl sulfate in solution. I will react this solution with a molar ratio of sodium nitrate—about 53 g. 7 g of potassium carbonate (~6.9% based on 210 g sodium ethylsulfate sol.) will be used and 6 g of cetyl alcohol hair-conditioner. e
6 g of hair-conditioner was added to a 500 mL flask equipped for distillation, followed by 7g of potassium carbonate dissolved into 27 mL of water. Stirring is activated and 53 g of sodium nitrite is added. The oil bath is heated to 155C and the sodium ethylsulfate sol is added dropwise. The addition was stopped because it took some time for distillate to occur then continued at the rate of distillation. After the addition 100 mL of water was added dropwise and the distillation continued to make sure all of the nitroethane distilled over. About 150 mL of distillate, a mixture of water and yellow globules of nitroethane, was collected. This was extracted with ether (3 x 50 mL). The ether was removed by distillation, and the residue, maybe 15 mL, was saved to be further purified once more is collected.

Experimental 2: 600 mL of 95% ethyl alcohol was carefully mixed with 300 mL of 96% sulfuric acid. A titration was done showing it was a 9.26 molar solution. 840 mL required 7.78 mole Ca(OH)2 is required to neutralize this solution so 575 g of Ca(OH)2 was mixed with 2000 mL of water in a large pitcher and the 840 mL of ethylsulfate/alcohol solution was carefully added to this with stirring. After the the ethylsulfate solution had been reacted with the Ca(OH)2 another 500 mL of water was added to assist in extraction and filtering as the mixture was very thick. The CaSO4 formed was filtered through clothe and then through filters until the solution was clear, resulting in 1970 mL of CaEtHSO4 solution. 100 mL of this solution was reacted with an excess of Na2CO3 and the chalk vacuum filtered, dried in an oven, and weighed (4.4 g) to determine the amount of Na2CO3 needed for neutralization. In this case 0.87 mol or 91 g of Na2CO3 (4.4 g/100 = 0.044 mol; 0.044 mol x 19.7 = 0.87 mol; 0.87 * 106 = 91 g). I used 92 g as an excess was recommended. The resulting solution had a pH of 9.4 and turned red indicator paper a vibrant blue. The mixture was vacuum filtered. Do not try to filter all of the CaCO3 all at once unless you have a gigantic filter because it will not fit. I had a fairly large Buchner and did half of the mixture; I rinsed the chalk, emptied the Buchner funnel, changed the filter, and then did the other half. The filtrate was refiltered by gravity filtration until clear and then evaporated on a pyrex cakepan with a fan blowing over it overnight. CaCO3/NaEtHSO4 salts precipitated during the evaporation. These were filtered and saved for further experimentation and the filtrate, 256 g/200 mL (Density: 1.28), was used in the next step. It will be assumed that 0.87 mol or 124 g of sodium ethyl sulfate is in solution and this will be reacted in a molar ratio to sodium nitrate (58 g). To a 500 mL flask with three-neck adapter, equipped with mechanical stirring, for distillation, and with an addition funnel, was added a squirt (5-7 g) of cetyl alcohol hair-conditioner, 30 mL of water, and 8 g of potassium carbonate. This was mixed, placed into an oil-bath and the oil-bath heated quickly to 155C with occasional stirring. Once the oilbath reached 155C the addition funnel was charged with the NaEtHSO4 solution and the addition began. The addition was carried out very slowly at first and then accidently nearly all of the NaEtHSO4 was added within 20 min.I allowed this mixture to distill for a long time before adding the last 20-30 mL. The distillate, water with yellow oil globules present was extracted with ether and the ether removed by distillation. The residue (12 mL) was saved to be purified further when more nitroethane has been collected.

Experimental 3: The sodium ethylsulfate sol. was prepared as above, except the titrations and sample reactions were not done; the ethylsulfate sol. made by reacting 600 mL 95% ethyl alcohol and 300 mL 96% H2SO4 was reacted with amounts as above (i.e. 575 g Ca(OH)2, 92 g Na2CO3) and then evaporated to a manageable amount (125 mL). The NaEtHSO4 solution was reacted with 60 g of NaNO2 in 30 mL of H2O with 10 g of K2CO3 and a squirt of cetyl alcohol hair conditioner. After the addition 50 mL of water was added. About 400 mL of distillate was collected. The yellow globules of nitroethane were apparent. This was extracted with ether (2 x 50 mL). The ether removed by distillation and the residue (22 mL) was added to the previously collected nitroethane.

organichem - 20-11-2013 at 07:25

A maybe interesting article I found:
Improved chemoselective, ecofriendly conditions for the conversion of primary alkyl halides into nitroalkanes under PEG400

Formula409 - 8-12-2013 at 17:42

Quote: Originally posted by organichem  
A maybe interesting article I found:
Improved chemoselective, ecofriendly conditions for the conversion of primary alkyl halides into nitroalkanes under PEG400

Thank you for the article link!

Attachment: Improved chemoselective, ecofriendly conditions for the conversion of primary alkyl halides into nitroalkanes under PEG4 (87kB)
This file has been downloaded 1589 times

PHILOU Zrealone - 25-12-2013 at 09:29

@Formula409,
Thanks for the attached article.

Very interesting...
Maybe it could work with lower MW PEG like diethylene glycol, triethylene glycol, ...
Should also work with 1,4-dioxane (O(-CH2-CH2-)2O)... or related crown ethers and cryptants...

SM2 - 25-12-2013 at 09:43

I hope the Epsom Salts were anhydrous

sulfuric acid is the king - 21-2-2017 at 17:28

If i try to do nitration of butane with NO2 in regular steel pipes can they sustain that for just one time?

sulfuric acid is the king - 22-2-2017 at 11:39

What about ethyl iodide and sodium nitrite under high pressure?

PHILOU Zrealone - 22-2-2017 at 15:34

Quote: Originally posted by sulfuric acid is the king  
If i try to do nitration of butane with NO2 in regular steel pipes can they sustain that for just one time?

Better do butane and dilluted HNO3 vapour at arround 350°C...you will get nitrobutanes, nitropropanes, nitroethane and nitromethan.

Butane NO2 mix may be explosive...

PHILOU Zrealone - 22-2-2017 at 15:36

Quote: Originally posted by sulfuric acid is the king  
What about ethyl iodide and sodium nitrite under high pressure?

The high pressure is not needed...but you need a good solvent for both CH3-CH2-I and NaNO2 (DMF or DMSO)...also you will get more ethyl nitrite ester than nitro ethane with NaNO2...better use dry AgNO2 .

sulfuric acid is the king - 22-2-2017 at 16:12

@PHILOU Zrealone
Thanks for the answers.
Can you explain me how high pressure is not needed when ethyl iodide has lower boilng point than nitroethane,i thought to react it in closed vessel,and then release vapor.
About butane...Yea it would be nice with acid way,but i need more vessels,acid needs to be heated etc etc...

[Edited on 23-2-2017 by sulfuric acid is the king]

[Edited on 23-2-2017 by sulfuric acid is the king]

byko3y - 23-2-2017 at 14:01

PEG is another solvent for both the EtI and NaNO2. Ratio of nitroethane:ethyl nitrite is somewhere at 3:2 or maybe even 2:1 for best known procedures.
It's a good idea to distill nitrite ester as fast as it is formed.

sulfuric acid is the king - 23-2-2017 at 15:41

You both think about "cold reaction"?Can it work that way?

[Edited on 24-2-2017 by sulfuric acid is the king]

sulfuric acid is the king - 23-2-2017 at 15:55

Can i use diethylether as a solvent?
What about ethyl chloride is it better than iodide?
I do not have silver nitrite,it's to expensive to disolve silver in nitric acid and then futher process to nitrite :D
Name me some other metal nitrites better than sodium?

byko3y - 23-2-2017 at 20:22

You should really try to stick to performing experiments someone already extensively developed, because you have no idea what you talk about.

sulfuric acid is the king - 24-2-2017 at 05:18

Quote: Originally posted by byko3y  
You should really try to stick to performing experiments someone already extensively developed, because you have no idea what you talk about.

I expected more constructive answer from organic chemistry Ph.D. ,IQ160...

clearly_not_atara - 24-2-2017 at 13:20

It seems that overall the less polar the solvent is, the higher the ratio of nitro:nitrite. From what I've seen, PEG > DMF > DMSO > alkylene carbonates > alcohols > water as far as nitro compound formation is concerned.

https://en.wikipedia.org/wiki/Lithium_nitrite#Crystallizatio...

According to Wikipedia, lithium nitrite is significantly more soluble in dry alcohol than potassium nitrite, which hints that it may also be more soluble in other organic solvents than sodium nitrite. LiNO2 may be a cheaper alternative to AgNO2: not quite as soluble in organics, but better than NaNO2 or KNO2, which is consistent with what we know about other lithium salts.

It's possible that lithium nitrite in absolute ethanol would be enough for a good yield of nitroalkane, but if not it might work in one of the other solvents listed above.

sulfuric acid is the king - 3-3-2017 at 17:52

How long can nitroalkanes be stored,what are degradation factors?

sulfuric acid is the king - 7-3-2017 at 16:05

Hmm,can i do something with ethyl chloride?
I know boiling point is lower than room temperature,but some pressurized one pot method or some solvent,what YOU members of the forum think about this idea,any suggestions?

Melgar - 10-3-2017 at 09:00

If less polar solvents produce more of the nitro compound, this would seem to be an ideal use case for phase-transfer catalysts. Sodium nitrite in the aqueous phase, then ethyl bromide in DCM, with TBAB as the PTC?

I think that for this type of substitution reaction, you need an organobromide at minimum. If you have ethyl chloride, you can convert it to the bromide in anhydrous conditions by bubbling HBr through it in the presence of an aluminum​ catalyst. AlBr3 converts alkyl chlorides to alkyl bromides, producing AlCl3. And HBr reacts with AlCl3 to produce AlBr3.

clearly_not_atara - 11-3-2017 at 00:48

It appears you've got the right idea:

http://www.tandfonline.com/doi/pdf/10.1080/00304948809356305

RosarioHeis - 19-3-2017 at 22:20

Why nitroethane can not be fractional distilled directly from dmf/NaNO2 solution? And what about extracting nitroeth from dmf with petroleum ether? The last is not soluble in it.

byko3y - 20-3-2017 at 10:12

Nitroethane boiling poing is much higher than boiling point of any ethyl halide (12°C, 38-39°C, 72-73°C for Cl, Br, and I).
DMF is soluble in pet. ether, but not miscible with it. Nitroethane is polar and acidic, thus alcohols, ethers are the best solvents for this compound (miscible). I know that 1-nitropropane is miscible with sulfolane, and methanol is not miscible with hexane below 25°C.
This gives me some signs that nitroethane is much more soluble in DMF than in the pet. ether. To fix the problem, water should be added to the mixture - which is the workup you all know.

[Edited on 20-3-2017 by byko3y]

Waffles SS - 1-9-2018 at 04:30

I found interesting methods for synthesis Nitroethane

Reaction of Ethyl Tosylate + NaNO2 = EtNO2

Rodionow - Bulletin de la Societe Chimique de France, 1926, vol. <4> 39, p. 318,
Bulletin de la Societe Chimique de France, 1929, vol. <4> 45, p. 119

and

Triethyl Borate + HNO3 = EtNO2

Schiff, H.; Liebigs Ann. Suppl.-Bd.; vol. 5; (1867); p. 154 - 182 ; (from Gmelin)
(thanks S.C .Wak for finding reference)
https://babel.hathitrust.org/cgi/pt?id=uva.x002457974;view=1...

It seems Borate ester is interesting and cheap method if it work !

[Edited on 1-9-2018 by Waffles SS]

LabRatNW - 18-9-2018 at 09:24

I don't think nitroethane would be soluble in petroleum ether at all. True ethers, definitely.

clearly_not_atara - 18-9-2018 at 09:52

That method from ethyl tosylate might go well with Loptr's synthesis of tosylates:

https://www.sciencemadness.org/whisper/viewthread.php?tid=91...

Not clear if a nitrite scavenger (resorcinol) is needed. Someone will have to do the forensics to find that old-ass paper.

Boffis - 20-9-2018 at 09:15

Quote: Originally posted by Waffles SS  
Triethyl Borate + HNO3 = EtNO2

Schiff, H.; Liebigs Ann. Suppl.-Bd.; vol. 5; (1867); p. 154 - 182 ; (from Gmelin)
(thanks S.C .Wak for finding reference)
https://babel.hathitrust.org/cgi/pt?id=uva.x002457974;view=1...

It seems Borate ester is interesting and cheap method if it work !

[Edited on 1-9-2018 by Waffles SS]


@waffles, it that a typo error or did you really mean HNO3 ie nitric acid rather than nitrous acid. If you do mean nitric acid what is the reaction?

Waffles SS - 20-9-2018 at 09:30

Quote: Originally posted by Boffis  
Quote: Originally posted by Waffles SS  
Triethyl Borate + HNO3 = EtNO2

Schiff, H.; Liebigs Ann. Suppl.-Bd.; vol. 5; (1867); p. 154 - 182 ; (from Gmelin)
(thanks S.C .Wak for finding reference)
https://babel.hathitrust.org/cgi/pt?id=uva.x002457974;view=1...

It seems Borate ester is interesting and cheap method if it work !

[Edited on 1-9-2018 by Waffles SS]


@waffles, it that a typo error or did you really mean HNO3 ie nitric acid rather than nitrous acid. If you do mean nitric acid what is the reaction?



Untitled.jpg - 72kB

[Edited on 20-9-2018 by Waffles SS]

byko3y - 20-9-2018 at 12:00

Quote: Originally posted by Waffles SS  

Triethyl Borate + HNO3 = EtNO2
Schiff, H.; Liebigs Ann. Suppl.-Bd.; vol. 5; (1867); p. 154 - 182 ; (from Gmelin)
The equation appears to be incorrect. At p. 168 author states "B(C2H5)3O3 + 3 NHO3 = BH3O3 + 3 N(C2H5)O3", thus the product is ethyl nitrate - same as the one made by reacting nitric acid and ethanol directly.

Waffles SS - 20-9-2018 at 22:30

Quote: Originally posted by byko3y  
The equation appears to be incorrect. At p. 168 author states "B(C2H5)3O3 + 3 NHO3 = BH3O3 + 3 N(C2H5)O3", thus the product is ethyl nitrate - same as the one made by reacting nitric acid and ethanol directly.


Interesting point.Thanks
I didnt see this equation so far. It seems we cant trust to all of the reaxys result


[Edited on 21-9-2018 by Waffles SS]

Mush - 9-12-2018 at 08:57

Quote: Originally posted by anomolous  
The reason I was attracted to this route was its apparent simplicity. I may try vacuum distilling instead of extracting with a solvent. But I don't understand why a solvent extraction wont work? Has anyone dealt with DMSO before? It seems to have strange characteristics. Is there something I'm missing? Do you think vacuum distillation is the answer or is there some other method of extracting the nitroethane you'd recommend?

Another method using 2-bromoproprionic acid was mentioned on the Rhodium archive. Nitroethane Synthesis: A Compilation, method 7. It is the destructive distillation of 2-bromoproprionic acid. It occurs in a solution of K2CO3 with NaNO2. Follows is the reference: V. Auger. Bull Soc. Chim. France Post no 3,23,333 (1900). If you can find it please share. Though the yields are so-so (50%) I may give this method a try. But the patent method still haunts me.


V. Auger. Bull Soc. Chim. France Post no 3, 23, 333 (1900)
https://gallica.bnf.fr/ark:/12148/bpt6k5774483h/f396.image.r...

Attachment: V. Auger. - Bull Soc. Chim. France no3, vol 23, p.333-336 (1900).rar (1.5MB)
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Rây, P. C., & Neogi, P. (1906).
CLXXXIV.—The interaction of the alkylsulphates with the nitrites of the alkali metals and metals of the alkaline earths.
J. Chem. Soc., Trans., 89(0), 1900–1905.
doi:10.1039/ct9068901900

CCXXI.—Interaction of alkali alkyl sulphates and alkali nitrites: theories of the formation of aliphatic nitro–compounds
Panchānon Neogi
J. Chem. Soc., Trans., 1914,105, 2371-2376
doi.org/10.1039/CT9140502371

Attachment: J. Chem. Soc., Trans., 1906,89, 1900-1905.pdf (415kB)
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From ethyalmine with peroxymonosulfuric acid

Ueber die Oxydation des Aethylamins
Eug. Bamberger
doi.org/10.1002/cber.19020350480
Chemische Berichte; vol. 35; (1902); p. 4294

Sulfomonopersäure als Mittel zur Structurbestimmung bei Aminen
Chemische Berichte; vol. 36; (1903); p. 711
Eug. Bamberger
10.1002/cber.190303601145

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[Edited on 9-12-2018 by Mush]

S.C. Wack - 16-2-2019 at 21:04

THE RELATIONSHIP OF THE CONSTITUTION OF CERTAIN ALKYL HALIDES TO THE FORMATION OF NITROPARAFFINS AND ALKYL NITRITES
BY ROBERT B . REYNOLDS AND HOMER ADKINS
1929, with AgNO2 and no solvent.

The Reaction of Silver Nitrite with Primary Alkyl Halides
BY NATHAN KORNBLUM, BERNARD TAUB, AND HERBERT E. UNGNADE
1954, different instructions, in ether.

Attachment: jacs_51_279_1929.pdf (576kB)
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Attachment: jacs_76_3209_1954.pdf (389kB)
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