AndersHoveland
Hazard to Other Members, due to repeated speculation and posting of untested highly dangerous procedures!
Posts: 1986
Registered: 2-3-2011
Member Is Offline
Mood: No Mood
|
|
Common Refrigerant into Dinitrofluoromethane
Can anyone provide any help on how to turn 1,2-difluoroethane, which is commonly found in compressed gas computer keyboard cleaners, into
1,2-dichloro-1,2-difluoroethylene?
Ideally, the 1,2-dichloro-1,2-difluoroethylene would be completely free of other isomeric impurities. What is the best route to accomplish this?
I was thinking gaseous chlorination in the presence of sunlight, but this is going to give several different isomers.
Starting with difluoroethane would be preferable because it is so commonly available in stores, and because since the molecule already contains
fluorine, no difficult fluorinating agents will be required to make the final product.
Here is what some research has so far turned up:
1,2-difluoro-tetrachloroethane can be reduced to CFCl=CFCl using Zn in 80% yield, other isomers are also formed and are difficult and impractical to
remove before subsequent nitration.
If there was some way to get good yields of CFClH-CFClBr, then this could be reacted with NaOH to pull out the HBr, leaving CFCl=CFCl. But I just do
not see this as feasible.
"The nitration (using a 65:85 ratio of pure HNO3 and 30% concentrated oleum, respectively) of 1,2-dichloro-1,2-difluoro ethylene, ClFC=CFCl, gives
chlorofluoronitroacetic acid (40% yield), with a formula HOC(=O)CFCl(NO2). Chlorofluoronitroacetic acid reacts with red fuming nitric acid (HNO3 /
NO2) to give chlorofluoronitronitrosomethane, with a formula O=N--CFCl(NO2), and which possesses a deep blue color. I.V. Martynov, Y.L. Kruglyak, S.
Markarov. Zh Obshch. Khim. volume 33, p3385. (1963)
This latter compound was then oxidized to dinitrofluorochloromethane, using HNO3 / H2O2, and next reduced (using potassium iodide) to
dinitrofluoromethane, and simultaneosly reacted with formaldehyde (in a single step) to give 2,2-dinitro-2-fluoroethanol, with a formula
HOCH2CF(NO2)2."
(Note that 2,2-dinitro-2-fluoroethanol is highly toxic and absorbs through skin!)
[Edited on 18-10-2011 by AndersHoveland]
|
|
|
SmashGlass
Hazard to Self
Posts: 52
Registered: 25-1-2011
Location: Scandinavia
Member Is Offline
Mood: No Mood
|
|
Sorry dude you are seriously barking up the wrong tree there.
There are much easier ways to make what you are looking for.
But none which are reasonable methods for the "home" chemist.
Go buy your own version of Reaxys or SciFinder first.
It will save everyone's time and sanity.
If it ain't broke don't fix it....
Now where are my screwdrivers?  |
|
|
AndersHoveland
Hazard to Other Members, due to repeated speculation and posting of untested highly dangerous procedures!
Posts: 1986
Registered: 2-3-2011
Member Is Offline
Mood: No Mood
|
|
Combination of Alcohol with Nitro-derivatives of Styrene. By Bernhabd Florscheim (J.pr. Chem., 1902, [ii], 66,16—27).
| Quote: |
When o-bromostyrene is treated with cold fuming nitric acid, two dinitrobromostyrenes are obtained in addition to jo-nitrobenzoic acid.
a-p-Nitrophenyl-fibromonitroethylene separates from alcohol in yellow crystals, melts at 135—136°, combines only slowly with bromine, and, when
boiled with water, yields p-nitrobenzaldehyde, nitrobromomethane, nitric acid, and hydrogen bromide
|
In this reaction, essentially an R-CH=CHBr group is reacting with fuming nitric acid to form CH2Br(NO2)
Could the nitrobromomethane not simply be reacted with LiF dissolved in ether to obtain nitrofluoromethane? There are then various other methods to
add a second nitro group.
For example, here is the procedure for adding a second nitro group onto nitroethane, it would no doubt also work on nitrofluoromethane:
1,1-Dinitroethane
To a stirred solution of 2.66 g (66.5 mmoles) of sodium hydroxide in 15 ml of water at 20° was added 5.0 g (66.5 mmoles) of nitroethane. When all the
nitroethane dissolved, the solution was cooled to 5°-7° in an ice-water bath. The sodium salt of nitroethane was prepared as above. To the stirred
solution was added a solution of 20 g (288 mmoles) of sodium nitrite in 50 ml of water, followed by a solution of 4.4 g (13.4 mmole) of potassium
ferricyanide in 25 ml of water. Finally, 16.0 g of solid sodium persulfate (67 mmoles) was added all at once. The reaction temperature, moderated by
an ice-water cooling bath, increased to 50°. The orange mixture was stirred at 25° for 1 hour and then cooled to 10°. Urea, 20 g (0.33 mole), was
added, followed by 10 ml of glacial acetic acid. The mixture was extracted with three 25 ml portions of ether and the combined extracts were washed
with brine and dried. The crude product was distilled to give 4.2 g (52% yield) of 1,1-dinitroethane, b.p. 87°-89° (16 mm), identified by its nmr
spectrum.
Patent 4910322
[Edited on 19-10-2011 by AndersHoveland]
|
|
|
AndersHoveland
Hazard to Other Members, due to repeated speculation and posting of untested highly dangerous procedures!
Posts: 1986
Registered: 2-3-2011
Member Is Offline
Mood: No Mood
|
|
Another idea:
Distill sodium fluoroacetate (extremely poisonous) with acetyl chloride to form fluoro-acetic anhydride.
FCH3C(=O)-O-C(=O)CH3
Of course this would be extremely dangerous, as the vapors would be deadly.
Then react with concentrated nitric acid to produce trinitrofluoromethane (tetranitromethane would also be produced as a byproduct). This would be
analogous to the reaction already well described on this forum:
http://www.sciencemadness.org/talk/viewthread.php?tid=1181&a...
Then reduce the trinitrofluoromethane to dinitrofluoromethane.
"The kinetics of the denitrification of fluorotrinitromethane to fluorodinitromethane under the action of potassium iodide in 70% ethanol was
investigated."
Kinetics and mechanism of the reaction of nitro and halonitro compounds with potassium iodide and other reducing agents
V. I. Slovetskii, M. Sh. L'vova, A. A. Fainzil'berg and T. I. Chaeva
Dinitrofluoromethane has the formula FCH2(NO2)2, and is the main precursor for the experimental energetic/explosive plasticiser/binder known as FEFO,
which first appeared online here: http://yarchive.net/explosives/astrolite.html
Two plastic bonded explosive formulations that contain a small portion of FEFO are LX-09-0 and LX-09-1.
[Edited on 19-10-2011 by AndersHoveland]
|
|
|
DDTea
National Hazard
Posts: 940
Registered: 25-2-2003
Location: Freedomland
Member Is Offline
Mood: Degenerate
|
|
| Quote: | | Could the nitrobromomethane not simply be reacted with LiF dissolved in ether to obtain nitrofluoromethane? There are then various other methods to
add a second nitro group. |
This won't work as you expect it to--are you thinking of an Sn2 reaction? LiF is not going to dissolve well in ether. DMSO would be a better solvent.
Also, F- is an abysmal nucleophile. Nucleophilic substitution would be near impossible.
You should look into common (and modern) methods for nitrating alkenes. This may be a good starting point:
"The nitro group in organic synthesis" by Noboru Ono. A preview is available for free on google. Page 11 is where you want to look.
Another safety consideration: lightweight molecules containing nitro groups and halogens tend to be very potent lachrymators. Eye and respiratory
protection will definitely be in order.
"In the end the proud scientist or philosopher who cannot be bothered to make his thought accessible has no choice but to retire to the heights in
which dwell the Great Misunderstood and the Great Ignored, there to rail in Olympic superiority at the folly of mankind." - Reginald Kapp.
|
|
|
AndersHoveland
Hazard to Other Members, due to repeated speculation and posting of untested highly dangerous procedures!
Posts: 1986
Registered: 2-3-2011
Member Is Offline
Mood: No Mood
|
|
Quote: Originally posted by DDTea  | LiF is not going to dissolve well in ether. DMSO would be a better solvent. Also, F- is an abysmal nucleophile. Nucleophilic substitution would be
near impossible.
|
You may be right. Other lithium salts, however, are more soluble in ether, especially lithium perchlorate, because the lithium ion tends to form an
adduct with the oxygen atom of the ether.
Nucleophilic substitution between halogens are possible.
See in the SM library:
"Copper-Catalyzed Halogen Exchange in Aryl Halides: An Aromatic. Finkelstein Reaction." Artis Klapars and Stephen L. Buchwald
|
|
|
UnintentionalChaos
International Hazard
Posts: 1454
Registered: 9-12-2006
Location: Mars
Member Is Offline
Mood: Nucleophilic
|
|
| Quote: Originally posted by DDTea | | Quote: | | Could the nitrobromomethane not simply be reacted with LiF dissolved in ether to obtain nitrofluoromethane? There are then various other methods to
add a second nitro group. |
This won't work as you expect it to--are you thinking of an Sn2 reaction? LiF is not going to dissolve well in ether. DMSO would be a better solvent.
Also, F- is an abysmal nucleophile. Nucleophilic substitution would be near impossible.
|
Even if F- is an abysmal nucleophile, it can be done. See: http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv4...
Department of Redundancy Department - Now with paperwork!
'In organic synthesis, we call decomposition products "crap", however this is not a IUPAC approved nomenclature.' -Nicodem
|
|
|
ThatchemistKid
Hazard to Others
Posts: 132
Registered: 2-6-2010
Member Is Offline
|
|
actually in DMSO the nucleophilicy of the halogen anions is reversed, fluoride is a pretty good nucleophile in DMSO and DMF, if I remember correctly.
|
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
