| Pages:
1
2
3 |
guy
National Hazard
Posts: 982
Registered: 14-4-2004
Location: California, USA
Member Is Offline
Mood: Catalytic!
|
|
O I see now. For some reason I was thinking the carbon had a negative charge, duh.
Then how does the chloroacetic acid route supposedly work? Would not the oxygen in nitrite attack the carbocation?
[Edited on 6/8/2006 by guy]
|
|
|
The_Davster
A pnictogen
Posts: 2861
Registered: 18-11-2003
Member Is Offline
Mood: .
|
|
Some sort of rearrangement follows, I am not really sure on how exactly it works. I know that when an alkyl halide is treated with nitrite that first
the alkyl nitrite is formed, which is volatile so some evaporates reducing yields, but the remainder rearranges to nitro.
|
|
|
Nicodem
Super Moderator
Posts: 4230
Registered: 28-12-2004
Member Is Offline
Mood: No Mood
|
|
There is no rearrangement involved. A nucleophilic substitution with the nitrite yields both the nitroalkane (R-NO2) and alkyl nitrite (R-O-NO). The
ratio of these two products depends on the conditions, but a problem is also in that the alkyl nitrites react with nitroalkanes thus reducing the
yield (thus phluoroglucinol or other alkyl nitrite scavengers are usually used for proper yields). The reason why you get two products (R-NO2 and
R-O-NO) lies in the ambident properties of the nitrite anion (NO2-). The negative charge can resonate between two forms, one having the (-) on the
oxygen and the other on the nitrogen. Thus the product ratio depends on which will be faster to react with the elctrophile (R-X) and this is highly
dependent on the nature of the counter ion, solvent and the electrophile.
| Quote: | Originally posted by guy
Wouldn't a nitration produce a nitro compound, not a nitrite ester? But anyways I found the answer, it is because aliphatic nitro compounds are
unstable in acidic environments. |
Nitration of alcohols gives alkyl nitrates (R-O-NO2). For obtaining nitroalkanes (R-NO2) one has to nitrate alkanes with HNO3, NO2 or other suitable
reagents, but the conditions required are pretty harsh (300°C, for example).
Aliphatic nitro compounds are extremely stable in acidic environment. You can mix nitromethane with strong acids like AlCl3 or H2SO4 and it won’t
affect them. On the other hand, if you first prepare a nitronate salt (like MeNO2 + NaOH -> NaO-NO=CH2) and then add acid a certain form of
oxidative hydrolysis occurs, the so called Nef reaction. But the nitronate salt is not the same as nitroalkane.
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
|
|
|
neutrino
International Hazard
Posts: 1583
Registered: 20-8-2004
Location: USA
Member Is Offline
Mood: oscillating
|
|
>For obtaining nitroalkanes (R-NO2) one has to nitrate alkanes with HNO3, NO2 or other suitable reagents, but the conditions required are pretty
harsh (300°C, for example).
What do you make of this, then?
| Quote: | | Standard gasoline, get the cheap stuff and not gasahol (gas/ethyl alcohol mix) if you can avoid it, is added gradually to a mixture of 15 parts 100%
sulfuric acid and 3 parts 100% nitric acid in a large beaker. Add 1 part of gasoline per 18 parts of mixed acid. The reaction temperature should be
somewhat cool, never let the temperature rise above 80 °C. A temperature below 20 °C should do, you can regulate this with a salt-ice bath. When the
nitration is completed, the mixture is diluted with a large quantity of cold water to precipitate the product. The un-nitrated oil will float to the
top of the acid-water solution. Collect the precipitate on a filter and wash with water, yield will be 30% to 90% depending on the crude oil used to
manufacture the gasoline. You will need a graduated cylinder for measuring liquids, and a thermometer to monitor the temperature.
|
It looks like a low temperature nitration with ordinary mixed acids. Then again, this procedure may have been done with oils with high aromatic
contents, different from today's mainly aliphatic gasolines.
|
|
|
Nicodem
Super Moderator
Posts: 4230
Registered: 28-12-2004
Member Is Offline
Mood: No Mood
|
|
That procedure is obviously meant to nitrate the aromatic fraction of gasoline. Though, it should talks about crude oil as some have a very high
content of the aromatics (normally about 20%, but some exceptions like some petroleum from Siberia even up to 60%!). I think today that procedure is
quite obsolete, since the new regulations (like the 1990 Clean Air Act Amendments in USA) make it mandatory to reduce the aromatic content (especially
benzene and polyaromatics) in gasoline to minimum. I wander if it was even tried on today’s gasoline as described above.
Anyway, aromatic nitration by electrophilic substitution like this is way different than radical nitration of alkanes in gas phase (where H2SO4 does
not help).
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
|
|
|
Vitus_Verdegast
Hazard to Others
Posts: 297
Registered: 5-12-2004
Location: Ottoman Empire
Member Is Offline
Mood: tea time
|
|
These are the papers on vapour phase nitration by the G. Bryant Bachman group (J Org. Chem. 1952, 7, 17, p. 906-954) :
http://rapidshare.de/files/28835243/Nitration_Studies._I._Ge...
http://rapidshare.de/files/28835403/Nitration_Studies._II._E...
http://rapidshare.de/files/28835491/Nitration_Studies._III._...
http://rapidshare.de/files/28835555/Nitration_Studies._IV._E...
http://rapidshare.de/files/28835657/Nitration_Studies._V._Ef...
Sic transit gloria mundi
|
|
|
Sandmeyer
National Hazard
Posts: 784
Registered: 9-1-2005
Location: Internet
Member Is Offline
Mood: abbastanza bene
|
|
There are a couple of threads on nitroethane production and since this is the longest one I'll post in here.
D. Kim and co-workers have published an interesting total synthesis of interesting structure (-)-brefeldin A in which a key step is an intramolecular
nitrile-oxide cycloaddition. The substrate for this step was prepared via a double Finkelstein reaction, first an alkyl tosylate was turned into
iodide, then the iodide was swaped with a nitrite to give nitroalkane. Interesting step for this discussion is that going from alkyl iodide to
nitroalkane. It was done using NaNO2, urea and DMSO as solvent under room temperature for 15 h giving the nitroalkane in 75% yield, these conditions
obviously don't give isomeric alkyl nitrite...
(3) Iodination. A mixture of the above tosylate (107 mg, 0.25 mmol) and sodium iodide (753 mg, 5.02 mmol) in 2-butanone (12 mL) was refluxed for 1.5
h. After removal of the solvent, cold water was added to the residue. The mixture was extracted with EtOAc (30 mL x 3). The combined organic layers
were washed with saturated Na2S2O3 solution, saturated NaHCO3 solution, and brine, dried over anhydrous MgSO4, and concentrated in vacuo. The
resulting residue was purified by column chromatography on silica gel (EtOAc/ hexane, 2:3) to give the iodo compound (94 mg, 98%) as a colorless oil
[analysis data left out]
(4) Conversion to Nitro Compound. To a solution of the above iodo compound (93 mg, 0.24 mmol) in DMSO (4 mL) were added urea (101 mg, 1.68 mmol) and
sodium nitrite (83 mg, 1.20 mmol) at room temperature. After 15 h, the mixture was poured into water and extracted with EtOAc (30 mL x 3). The
combined organic layers were washed with water, dried over anhydrous MgSO4, and concentrated in vacuo. The resulting residue was purified by column
chromatography on silica gel (EtOAc/hexane, 2:3) to give nitro compound 17 (54 mg, 75%) as a colorless oil. [analysis data left out]
Asymmetric Total Synthesis of (+)-Brefeldin A from (S)-Lactate by Triple Chirality Transfer Process and Nitrile Oxide Cycloaddition
Kim, D.; Lee, J.; Shim, P. J.; Lim, J. I.; Jo, H.; Kim, S.
J. Org. Chem.; (Article); 2002; 67(3); 764-771. DOI: 10.1021/jo010743i
Full-text: http://rapidshare.com/files/2917645/brefeldin.pdf.html
Of course, making nitroethan itself is stupid idea, there are other routes to amphetamines...
[Edited on 11-11-2006 by Sandmeyer]
|
|
|
jim20/20
Harmless
Posts: 25
Registered: 10-7-2006
Member Is Offline
Mood: No Mood
|
|
| Quote: | Originally posted by Sandmeyer
Of course, making nitroethan itself is stupid idea
[Edited on 11-11-2006 by Sandmeyer] |
for sure by this method
4l of dmso to get 54g of ne if the ratios are crucial
urea replaces phloroglucinol in this method and possibly is not so soluble in dmso
|
|
|
Sandmeyer
National Hazard
Posts: 784
Registered: 9-1-2005
Location: Internet
Member Is Offline
Mood: abbastanza bene
|
|
Of course, I agree, I don't know of any kitchen-friendly method to make it, nor do I see a reason to do so. If one can't get it it's time to look
outside the Henry condensation box.
|
|
|
hector2000
Hazard to Others
Posts: 127
Registered: 22-8-2006
Member Is Offline
Mood: Cool
|
|
Patent number# 4319059
| Quote: |
To a mixture of magnesium methoxide (0.11 mole) and dimethyl sulfoxide (50 ml) α-bromopropionic acid (0.11 mole) ws 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. The product was analyzed on a
3'×3/16" Porapak Q column for nitroethane at 150° C. and on a 3'×3/16" column packed with 10% ethylene glycol adipate and 1% phosphoric acid on
Chromosorb AW 80/100 mesh for α-bromopropionic acid at 150° C. This analysis of the reaction mixture indicated more than 99% conversion of
α-bromopropionic acid and 94.5% yield of nitroethane
|
α-bromopropionic acid is 2-bromopropionic acid ?
Yield is acceptable?94.5% 
Attachment: US4319059.pdf (94kB)
This file has been downloaded 895 times
[Edited on 1-6-2009 by hector2000]
Chemistry=Chem+ is+ Try
|
|
|
benzylchloride1
Hazard to Others
Posts: 299
Registered: 16-3-2007
Member Is Offline
Mood: Pushing the envelope of synthetic chemistry in one's basement
|
|
Does anyone have the procedure for the synthesis of nitromethane from methyl sulfuric acid? I searched for the Synthetikal site, but it currently does
not exist.
Amateur NMR spectroscopist
|
|
|
DJF90
International Hazard
Posts: 2266
Registered: 15-12-2007
Location: At the bench
Member Is Offline
Mood: No Mood
|
|
I would assume it to be similar to the rhodium prep for nitroethane, but adjusting the amount of carbonate to take into account for the free acid;
"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."
However this is just a suggestion, I would expect you to check it over before blindly stumbling forward 
[Edited on 18-6-2009 by DJF90]
|
|
|
benzylchloride1
Hazard to Others
Posts: 299
Registered: 16-3-2007
Member Is Offline
Mood: Pushing the envelope of synthetic chemistry in one's basement
|
|
Thank you very much for the preparation, DJF90. I am going to try the nitroethane synthesis first, I plan on using the nitroethane for the preparation
of some cryptan ligands. Nitromethane can be used to make similar ligands. I am working on the sodium ethyl sulfate synthesis; I am using the method
from Cohens Pratical Organic Chemistry, the author claims that from 87ml of ethanol, 45-50 grams of the salt can be prepared. I tried this synthesis
several years ago, it was a failure because I poured the hot reaction mixture directly into water instead of cooling it. Ethyl hydrogen sulfate
rapidly hydrolyses in acidic hot water. I will report back when the synthesis of the sodium ethyl sulfate is complete.
Amateur NMR spectroscopist
|
|
|
benzylchloride1
Hazard to Others
Posts: 299
Registered: 16-3-2007
Member Is Offline
Mood: Pushing the envelope of synthetic chemistry in one's basement
|
|
Sorry for the double post.
I attempted the sodium ethyl sulfate synthesis and obtained nothing beside a few crystals that when treated with hydrochloric acid produced carbon
dioxide like sodium carbonate. I evaporated the solution that was thought to contain the product to around 100ml, no large scale crystallization, even
after standing over night. The solution of ethyl hydrogen sulfate was cooled to 15 C before being poured into ice water. The solution was then
neutralized with calcium hydroxide, filtered, the calcium sulfate was washed with hot water and then the mixture was treated with sodium carbonate
solution until no more calcium carbonate precipitated. The solution was then filtered, the calcium carbonate precipitate washed with water and the
solution concentrated from about 600ml to 100 ml. Even after adding methanol, very little precipitated. I decided to discard the mixture. Has anyone
tried this preparation of sodium ethyl sulfate? I made several attempts at this several years ago. I wanted to make the sodium ethyl sulfate before
the sodium methyl sulfate because I have a known procedure.
[Edited on 19-6-2009 by benzylchloride1]
Amateur NMR spectroscopist
|
|
|
Sedit
International Hazard
Posts: 1939
Registered: 23-11-2008
Member Is Offline
Mood: Manic Expressive
|
|
Benzylchloride im not exactly sure which synthesis you attempted but here is a one for Sodium Ethyl Sulfate I myself wanted attempt sometime soon but
since you already seem to be in the swing of things perhaps you would not mind attempting this process posted by Evil_lurker some time back and
letting us know how it goes.
| Quote: |
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. |
If this is effective then I see no reason why the substitution of MeOH here would not form the desired sodium methyl sulfate.
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
|
|
|
DJF90
International Hazard
Posts: 2266
Registered: 15-12-2007
Location: At the bench
Member Is Offline
Mood: No Mood
|
|
This was posted some time before on sciencemadness. The patent is available on googlebooks:
http://www.google.com/patents?id=f15mAAAAEBAJ&printsec=a...
|
|
|
franklyn
International Hazard
Posts: 3026
Registered: 30-5-2006
Location: Da Big Apple
Member Is Offline
Mood: No Mood
|
|
Lower nitroparaffins are prepared by treating the corresponding C1-3 alkyl chlorides
with alkali metal nitrites in DMSO : CH3Cl + NaNO2 -> CH3NO2 , 85% yield
Takagi, U.; Tsumura, R.; Mazaki, T. Kokai Tokkyo Koho 79,125,604 (Cl. C07 C79/04)
(Sept.29, 1979); CA92, 110519H.
US patent 2105581 discloses this but in aqueous conditions and poorer yield.
This method from 1956 applies NaNO2 in Dimethylformamide _
http://www.sciencemadness.org/talk/files.php?pid=81599&a...
The proceedure given here -> http://www.orgsyn.org/orgsyn/pdfs/CV1P0401.pdf
is only good for 35 - 38 % yield. Quite a difference the choice of solvent makes.
CH3Cl should readily result from Methanol + Muriatic acid with a Lewis acid catalyst
Zinc or Aluminum predissolved in the HCl. Given that current price of CH3.NO2 motor
fuel is ~ $ 55 gal + shipping , the savings from homebrewed would only be modest.
Iodopicrin (CI3NO2) and silver nitrite (AgNO2) yield Tetranitromethane according to
Hantzsch, Ber., 1906 num 39, pg 2478 . I wonder if in DMSO Chloropicrin and NaNO2
could substitute ? Might this work with Chloroform , 1,1,1,Trichloroethane or
Tetrachloroethylene.to produce corresponding nitro compounds.
Related thread -> http://www.sciencemadness.org/talk/viewthread.php?tid=2995
.
|
|
|
franklyn
International Hazard
Posts: 3026
Registered: 30-5-2006
Location: Da Big Apple
Member Is Offline
Mood: No Mood
|
|
The opening citation of the post above is actually of a patent written in Japanese , some , but not this one,
provide cursory english translations. Available in Japanese here online
http://www4.ipdl.inpit.go.jp/Tokujitu/PAJlayout.ipdl?N0000=6...
The english Abstract is in the pdf here _ Attachment: Preparation of Lower Nitroparaffins - Japan Pat.pdf (148kB)
This file has been downloaded 1463 times
the table depicted on the next to last page confirms the preparation produces nitromethane in up to 55 % yield
in 2 hours under mild conditions. As I speculated above this method may have wider applications as yet untried.
Another paper describing this approach that I must have gotten here but I don't know who to attribute it to.
=> Attachment: Preparation of Nitromethane from Nitrite in DMSO.pdf (303kB)
This file has been downloaded 1065 times
Additional patents to those cited in the post above, US 2117931 , US 3014972
US patent 4424385 also references subsequent patents from the same Japanese inventors above.
For convenience here are those Abstracts => Attachment: Preparation of Lower NIitroparaffins.rtf (4kB)
This file has been downloaded 764 times
- Apply the step by step procedure I have outlined on the opening page of the first attached pdf
to access these two english abstracts and related publications as these here below.
S56-169648
http://www4.ipdl.inpit.go.jp/Tokujitu/PAJlayout.ipdl?N0000=6...
S56-169649
http://www4.ipdl.inpit.go.jp/Tokujitu/PAJlayout.ipdl?N0000=6...
.
|
|
|
| Pages:
1
2
3 |
![[*]](images/xpblue/default_icon.gif){kind=icon}
