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smuv
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Ethyl/Isopropyl Bromide preparation
I prepared ethyl bromide last night. The synthesis was quick easy and efficient, so I thought I would post my results.
Procedure
To a 500mL RB flask filled with 42mL of azeotropic ethanol, there was added 45mL of sulfuric acid (rooto drain cleaner) portion-wise with stirring.
After the flask had cooled somewhat, 33g of ammonium bromide (reagent grade) was added, as the contents of the flask were swirled. The flask was put
into an oil bath and set-up for simple distillation. The receiver was a 150ml beaker which was filled with enough ice water to partially immerse the
drip tip of the condenser under water. The flask was rapidly heated and shaken periodically; a nice red-orange hue from Br2 quickly developed. Soon
HBr vapors began fuming from the condenser, at which time a damp paper towel was draped over the receiver to absorb any evolved HBr. The fuming
ceased after a few minutes and ethyl bromide began coming over. The ethyl bromide was collected for about 25 minutes until only a water miscible
distillate could be collected.
Results
In total, 20mL of ethyl bromide was collected, corresponding to a 75% yield based upon the ammonium bromide. This synthesis was quick easy and high
yielding. Throughout the reaction not a hint of ethyl bromide could be smelled, although I got a few whiffs of it during clean up.
[Edited on 7-7-2008 by Polverone]
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Zinc
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Very interesting!!
I have heard that nitroethane can be made from EtBr and NaNO2, is that true?
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DJF90
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Yes, but its not particularly simple, and side product is ethyl nitrite. Method can be found on rhodium IIRC
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Zinc
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Too complicated for me to do those type of synthesizes.
Perhaps could ethyl nitrate be made from EtBr and Pb(NO3)2 or must silver nitrate be used?
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497
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Do you think this would work with methyl instead of ethyl? I don't see why not. The condenser would have to be much colder to accommodate its lower
boiling but other than that it should be simple.
Edit:
@Klute, Yes it boils at 3*C IIRC so I would use dry ice/acetone probably. I like the solvent idea though, I'll have to look in to that. And I just
wanted to know if it was possible, I doubt I'll have a chance to try it any time soon. I know it was in wide use for years as a soil sterlilant and
fumigant until they figured out it was so very good at destroying ozone, could it be that toxic?
[Edited on 2-7-2008 by 497]
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Klute
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Methyl bromide is a gas under STP. So you cannot condenser it without using dry ice/liq. N2.
You can however dissolove the gas in a suitable solvent, or introduce it as formed in a reaction medium for alkylating purpose, for example.
Painkilla succesfully did this, search for his thread in the Org Chem. forum. EDIT: here you go: Asymmetric Etherification of 1,4-dihydroxybenzene
Be carefull, MeBr is nasty stuff, you do not want to breath (cancerigenic). Considering it's a gas, you need a suitable setup and adequate
precautions. If you ever consider preparing it, I really advise you to read more on it.
[Edited on 3-7-2008 by Klute]
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
-Alice Parr
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garage chemist
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Vanino's book says some water must be added to the H2SO4/ethanol mix before introdution of the bromide salt, otherwise some of the HBr is evolved as
gas instead of reacting!
It seems like this is what happened to you.
The ethyl bromide yield can be as high as 90% if you do it right.
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smuv
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The two books I consulted said nothing about adding water; their yields were 80% but on a larger scale. If you factor in the ethyl bromide that was
lost to solubility in water the yields are pretty close to 80% even on a small scale.
In the book you quoted were they using azeotropic or anhydrous alcohol?
If I were to do it again I would disolve the ammonium bromide in the ethanol then carefully add the sulfuric acid. Maybe the addition of water could
help, but honestly I have never seen that anywhere else; I'll see what vogel says tonight but I dont recall that detail.
EDIT: But I do see how addition of water could help. I was just under the impression that the water in the ethanol should keep the production and
loss of anhydrous HBr minimal.
[Edited on 3-7-2008 by smuv]
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S.C. Wack
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| Quote: | Originally posted by smuv
Maybe the addition of water could help, but honestly I have never seen that anywhere else |
It's also in Mann and Saunders, and the 1937 Gattermann, using the K or Na salts.
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garage chemist
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They are using azeotropic ethanol in Vanino.
Here's the procedure from Vanino, translated from german:
To 1090ml 96% ethanol are added 1090ml conc. sulfuric acid rapidly with stirring.
After the mix has cooled down, 750ml icecold water are added with good stirring.
This mix is then added, with shaking, to 1kg potassium bromide in a 6l-flask and distilled at 110- 125°C oil bath temperature, at the end the bath
temperature is increased to 160°C.
The distillate is separated from any water, cooled with ice and salt and mixed dropwise with conc. H2SO4 until the acid layer sinks to the bottom.
The acid layer is discarded and the ethyl bromide washed with water, dried with CaCl2 and fractionally distilled on the water bath. Nearly all passes
over from 38-39°C.
Yield: 740g (510ml)
The water addition is very important for the success of the operation, omitting it not only leads to large HBr loss, but also to increased formation
of diethyl ether as an unwanted byproduct.
The treatment with H2SO4 removes the ether, the specific gravity of the H2SO4 first becoming lower than that of the ethyl bromide due to the ether
uptake until enough H2SO4 has been added for the acid layer to sink down.
The H2SO4 treatment also removes unreacted ethanol more efficiently than washing with water would do.
Pure ethyl bromide has a specific gravity of 1,47- 1,48 g/ml; a lower density of the obtained product would show that it contains diethyl ether.
Pure ethyl bromide also has to react neutral and must leave no trace of a pungent or garlic-like smelling less volatile residue upon rubbing some of
the liquid between the hands.
[Edited on 3-7-2008 by garage chemist]
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Siddy
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When i have prepared halides from alcohols, i have used excess HX source and a i utilize a NaOH trap. A rubber tube from the top of the condenser to
the a beaker of NaOH solution, no nasty fumes 
I suppose in this case, the EtOH is easier to get a cheaper than the Bromide source so thats why you used excess EtOH.
This method works for all primary aliphatic alcohols, even better with aromatic but gets complicated / hindered with secondary and tert. So yes, it
works with MeOH, from memory vogel describes the same method for halides.
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smuv
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| Quote: | | The ethyl bromide yield can be as high as 90% if you do it right. |
the procedure you posted has an 80.8% yield on a massive scale....and seems like it would take longer.
But ill give it a try on a smaller scale soon, just to see.
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MagicJigPipe
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I wanted to add that if you are using this for a Grignard Et2O "contamination" might be beneficiary. I assume the ratio of Et2O to EtBr could be
determined by density and then more could be added for use in a Grignard.
However, is it difficult to dry Et2O/EtBr mix without loss of Et2O? I never knew that to be the case.
"There must be no barriers to freedom of inquiry ... There is no place for dogma in science. The scientist is free, and must be free to ask any
question, to doubt any assertion, to seek for any evidence, to correct any errors. ... We know that the only way to avoid error is to detect it and
that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think,
free to think what they will, freedom can never be lost, and science can never regress." -J. Robert Oppenheimer
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garage chemist
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I have to admit I didn't calculate the percentage yield of the procedure from Vanino.
But you should really determine the density of the product and the gram yield of your procedure, smuv.
And ethanol contamination of the product is no doubt best taken care of, along with Et2O contamination, by the H2SO4 treatment in Vanino's procedure.
Intentionally leaving Et2O in the product seems to be unpracticable to me- it's really important that no ethanol is in the product, otherwise the
grignard won't start.
The temperature of the EtBr procedure is too low for efficient formation of Et2O anyway.
The preparation of methyl bromide is described in Vanino as well.
It is analogous to the EtBr preparation, and uses the proportions:
218ml H2SO4
150ml MeOH
150ml ice water
200g KBr
The resulting MeBr gas is taken off at the top of the reflux condenser, dried with calcium oxide and liquefied by a good ice/NaCl mix.
Vanino also describes the preparation of methyl chloride: A mix of 2 parts MeOH and 1 part anhydrous ZnCl2 is boiled under reflux while a rapid stream
of dry HCl gas is passed in.
The MeOH is completely converted into MeCl.
The gas is taken off at the top of the reflux condenser, washed with water to remove HCl and MeOH vapor, dried with CaCl2 and liquiefied with dry
ice/ether.
Alternatively, the MeCl can be dissolved into alcohol, which dissolves a large amount of the gas, stored this way, and liberated again by dropping the
solution into water, which produces a constant stream of the gas.
This storage method probably also works for MeBr.
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smuv
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Bromoethane a la Vanino
I again synthesized ethyl bromide, this time by the procedure from Vanino posted by garage chemist. I scaled the procedure down to use 33g of
ammonium bromide so that I could directly compare the two methods. To be clear: the main difference between the two procedures is the addition of
water. The hope is, that by adding water less bromide is lost as HBr and less Ether is able to form.
Procedure
A 200mL beaker was filled with 44mL azeotropic ethanol and allowed to cool a little in an ice bath. After a few minutes 44mL of rooto drain cleaner
(hopefully conc. H2SO4) was added in two portions with stirring; this solution was again allowed to cool. Next, 30mL of cold water (ca. 5 degrees C)
was added in two portions with stirring.
[img]http://i277.photobucket.com/albums/kk55/babygenius814/DSC01423.jpg?t=1215321703[/img]
(the water, ethanol, sulfuric acid solution)
After cooling back to around room temperature, this solution was added to 33g of ammonium bromide in a 500mL round bottom flask. After addition the
flask was swirled vigorously.
[img]http://i277.photobucket.com/albums/kk55/babygenius814/DSC01424.jpg?t=1215321846[/img]
(RB just after addition)
The flask was set-up for simple distillation and placed in an oil bath. The outlet of the receiver was immersed in water to minimize exposure to the
EtBr and monitor its production (visible oily drops sinking to the bottom). The oil bath temperature was rapidly raised to ~110c and then slowly over
the course of about 35-40 minutes brought to ~170c. The flask was swirled from time to time to maintain a steady production of bromoethane. EtBr
first started distilling around 105c, peaked around 125c and trailed off from there.
[img]http://i277.photobucket.com/albums/kk55/babygenius814/DSC01426.jpg?t=1215321897[/img]
(the set-up)
[img]http://i277.photobucket.com/albums/kk55/babygenius814/DSC01425.jpg?t=1215322021[/img]
(receiver)
Results
Surprisingly the yield via this method was exactly the same as the previous method (from Campbell and also Cohen); although it is possible that this
product contains less ether. Exactly 20mL of crude product was collected representing about a 75% yield.
[img]http://i277.photobucket.com/albums/kk55/babygenius814/DSC01427.jpg?t=1215322082[/img]
(crude product)
Final Thoughts
This alternative method of making bromoethane, in my opinion, is equal to the first. While there was no production of anhydrous HBr the prep took a
bit longer; required a solution to be prepared separately, and required a lot of time cooling between each dilution of the sulfuric acid. The Vanino
method produced EtBr more smoothly requiring less swirling throughout the process to maintain a steady rate of EtBr production. I don't think the
yields came out being any better, because I believe the amount of HBr lost in the previous method was very minor in the grand scheme of things. Also
I have found with my experiments preparing 2-bromopropane, that the production of anhydrous HBr in my first method could be greatly minimized with
less vigorous heating. The other problem with the Vanino method is that a lot more water comes over with the product, so it is hard to directly
obtain a reasonably dry product which can be quickly dessicated and stored (more on this when I talk about isopropyl bromide).
All in all, I think both methods have merits. I just think the method used is up to the chemist. If I were to do it again I would stick to my
original method; simply because there is less prep time, and a little HBr 'smoke' doesn't bother me (especially when i replace my broken vac adapter).
P.S. I did not do any further workup because I want to wait until I make some sort of ventilation system/hood before I expose myself to EtBr free from
a blanket of water.
P.P.S. I will post my IpBr syntheses tomorrow.
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not_important
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Seems to me you could use CaBr2 to complex the alcohol and water in the crude distilled product, leaving the alkyl bromide and most of the ether
behind. Add extra ether and separate liquid phases, or just use plenty of CaBr2 and filter off the complexes.
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Panache
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From a Rhodium thread on nitroalkane preperation
Ethyl Bromide
'1500 ml of concentrated H2SO4 was added to 900 ml H2O, then cooled. Then 1.5 l of absolute ethanol was slowly dripped in, carefully to avoid
temperature rise. Cool the mixture and add 1100-1200 g KBr (or equimolar amount of NaBr). Heat the mixture on a sand-bath at the lowest temperature at
which the ethylbromide distills over, collect it in water. Wash the ethyl bromide again with water and dry it with CaCl2. Yield 90-96%.'
This works as stated, with quantative yeilds if the reaction is kept as cool as possible. The 'lowest temperature at which ethyl bromide distils', ie
the temperature of the reaction matrix is initially 95C slowly creeping up to 105 over 6-8hrs. I have attempted stirring with it but found no
effective change in the way the reaction ran, which is unusual as its two phase, however as the ethyl bromide is formed slowly, and is removed slowly
as formed, i understand this to be the impediment to a faster reaction not stirring. The reaction time appears to remain constant. One can detect a
visual change slowly in the undissolved salts from initially K/Nabr to the sulphates. This reaction produces no HBr vapour as far i i can ascertain.
Now a question i have been meaning to ask for some time. A mixture of ethyl bromide and diethyl ether is a challenging separation, any ideas for this?
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smuv
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it's been covered; wash with H2SO4; it will absorb the ether via multiple reactions; namely formation of an etherate and ethyl sulfates.
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smuv
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Isopropyl bromide -- 2 ways
So yesterday I prepared isopropyl bromide from isopropanol via the two methods previously discussed in this thread. I originally thought elimination
to propylene would be a major competing reaction, so I first opted to try the method where the alcohol/sulfuric acid mixture is diluted with water.
Surprisingly I found the work up for this method to be a little tricky so next I tried the undiluted method on a large scale, and was pleased with the
results.
Isopropyl Bromide: Vanino method
Reagents
33g ammonium bromide
80mL 70% Isopropanol
44mL Sulfuric acid
9mL Water
[img]http://i277.photobucket.com/albums/kk55/babygenius814/DSC01428.jpg?t=1215372221[/img]
(IPA, Sulfuric acid, water solution)
Since 2-bromopropane is less volatile than ethyl bromide I decided to simply collect the distillate in a 100mL rb flask, as opposed to in a beaker
under a blanket of water.
[img]http://i277.photobucket.com/albums/kk55/babygenius814/DSC01429-1.jpg?t=1215372349[/img]
(The setup)
Everything seemed to proceed just like the ethyl bromide preparation, except as expected everything kicked in at lower temperatures. From what I
could tell during the synthesis elimination did not seem to be much of a problem. As time went on I noticed the receiver was getting pretty full
although I could not see a visible aqueous/organic interface. By the end of the run I had collected maybe 60-70mL of a turbid emulsion. I allowed
the flask to sit for a few hours, hoping that it would clear up; It didn't. I decided to add a little calcium chloride to get it to clear up, it
refused to. I added more with no luck. Surprisingly the calcium chloride did not dissolve within the solution. Next I decided to add some sodium
carbonate, and then just distill the damn thing to see if I could remove most of the water. Everything was set up for simple distillation and
everything up to 70c was collected (I would have done fractional but working on this scale with 24/40 joints is futile). I now had about 50mL of
milky distillate, I added CaCl2, and kept adding CaCl2, the damn thing never cleared up even after sitting for a day. So I momentarily gave up on the
workup and tried synthesizing IpBr another way. I am guessing that the workup gave me trouble because probably some isopropanol came over during the
synthesis.
[img]http://i277.photobucket.com/albums/kk55/babygenius814/DSC01441.jpg?t=1215377101[/img]
(Full of CaCl2 yet still turbid)
2-bromopropane the other way
After the previous experiment, feeling pretty confident that elimination would not be an issue, I decided to synthesize isopropyl bromide via the
undiluted method on a ~1 molar scale.
Everything was done as in the first post of this thread, except, in a 1L flask, w/ a 500mL receiver and I again decided not to collect the distillate
under water. Additionally, I decided to heat the oil bath less vigorously and shook the flask more frequently during the synthesis to prevent the
loss of HBr.
Reagents
180mL Isopropanol (Gas line antifreeze)
100g Ammonium Bromide
133mL Sulfuric acid
[img]http://i277.photobucket.com/albums/kk55/babygenius814/DSC01433.jpg?t=1215374020[/img]
(Mixed and ready for the oil-bath)
[img]http://i277.photobucket.com/albums/kk55/babygenius814/DSC01435.jpg?t=1215374108[/img]
(The set-up)
Only a puff of HBr 'smoke' came out of the condenser just before isopropyl bromide started coming over; the loss of bromide was trivial.
2-bromopropane was produced very quickly even with gentle heating. The solution frothed a lot and at one point the distillation flask had to be
lifted out of the oil bath to prevent a boil over.
[img]http://i277.photobucket.com/albums/kk55/babygenius814/DSC01436.jpg?t=1215374501[/img]
(Out of the bath, and just subsiding)
The synthesis minus workup took about 1 to 1.25 hours; 2-bromopropane just started coming over at around 100c, was most vigorous around 110-115c and
was taken all the way to 165c (albeit probably with some propylene gas coming over). Even at 165c an oily flammable liquid, which burned with a
sooty flame and produced HBr smoke was being produced.
The contents of the receiver were a little milky with obvious drops of water floating above an organic layer. About .75 grams of sodium carbonate was
added with shaking, producing little visible bubbling of CO2. Next, calcium chloride was added and swirled until the solution was transparent; then
about 50% more CaCl2 was added and the crude product was allowed to sit over night. The next afternoon the flask was swirled and shaken, the contents
remained completely transparent and deemed pure enough. The isopropyl bromide was transfered to a tared amber glass bottle.
[img]http://i277.photobucket.com/albums/kk55/babygenius814/DSC01438.jpg?t=1215375364[/img]
(Straight out of the ice bath, ready for transfer)
Via this method 113.5g of isopropyl bromide was produced representing a 90% yield.
Final thoughts
Via the undiluted method 2-bromopropane was quickly and easily produced without any annoying problems. I am sure a more patient person with a better
equipped lab could figure out an easy way to make 2-bromopropane via the other method, but I wont spend any more time with it. In my second attempt I
used a hefty excess of isopropanol, I predict this could safely be cut back a little without any impact upon yields.
This series of experiments has been interesting because it demonstrated the differences in reactivity between a primary and secondary alcohol.
[img]http://i277.photobucket.com/albums/kk55/babygenius814/DSC01439.jpg?t=1215376006[/img]
(burning 2-bromopropane absorbed onto a paper towel. Notice the sooty flame and HBr 'smoke').
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Panache
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| Quote: | Originally posted by smuv
it's been covered; wash with H2SO4; it will absorb the ether via multiple reactions; namely formation of an etherate and ethyl sulfates.
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But what if it was the ether i wanted to keep?
Only joking, have you since found any browning/disscolouration in your ethyl bromide? On one run when i went far too hot i recall that even after
fractionation it went brown after several days, a second sulphite wash cleared it up. Nice photo essay, that saucepan has seen better days. did
someone large sit on while it was sideways?
[Edited on 10-7-2008 by Panache]
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smuv
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Will It Work?
The ethyl bromide is in a amber glass bottle so it is hard to tell until I use it. The isopropyl bromide from the first run (the one I had trouble
with the work up) has been sitting in a clear 100ml rb flask with a cork stopper not too far from a window and there are no signs of bromine.
Just to document on the forum; I tried to make isopropyl chlroide via a similar method (using NaCl though) and as expected it failed; I only produced
propylene and anhydrous HCl.
I wonder if preparing ethyl chloride from ethanol, H2SO4 and NaCl would work. The way I see it, the ethyl sulfates formed en situ might posses a good
enough leaving group to allow the SN2 reaction to take place. I wonder if the higher temperatures required for elimination to occur on a primary
alcohol would allow the chlorination to take place before elimination. I know classically lewis acid catalysts like ZnCl2 should be used but my
understanding is that they complex with the alcohol removing electron density from the C-O bond allowing it to become a better leaving group; in the
big picture, not too different from the formation of a sulfate.
Anyone have anything that will just blow my self-serving speculation out of the water?
P.S. Panache: Thats not a saucepan, but a very sophisticated rigorously calibrated piece of equipment.
[Edited on 10-7-2008 by smuv]
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Panache
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| Quote: | Originally posted by Panache
| Quote: | Originally posted by smuv
it's been covered; wash with H2SO4; it will absorb the ether via multiple reactions; namely formation of an etherate and ethyl sulfates.
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But what if it was the ether i wanted to keep?
Only joking, have you since found any browning/disscolouration in your ethyl bromide? On one run when i went far too hot i recall that even after
fractionation it went brown after several days, a second sulphite wash cleared it up. Nice photo essay, that saucepan has seen better days. did
someone large sit on while it was sideways?
[Edited on 10-7-2008 by Panache] |
Oh my it has been a long time since i revisited that separation, i just went to get the ~1L out of the freezer and realised the difficult separation i
had was dichloromethane and ethyl bromide, not ether and ethyl bromide as i had incorrectly remembered it as being.
Does anyone have a non-chromatagraphic (is that a wword?) idea for separating around a 50/50 mix of these two.
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497
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Maybe freeze with LN2...
EtBr freezes at -119*C while DCM at -97*C... might not work out.
EtBr + Mg ---> EtMgBr maybe.
DCM has a water solubility about 10 times that of EtBr. That would be a pain in the ass though. Good luck.
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Nicodem
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| Quote: | Originally posted by smuv
I wonder if preparing ethyl chloride from ethanol, H2SO4 and NaCl would work. |
Using the search engine can often give you the answer if you dare using it:
http://sciencemadness.org/talk/viewthread.php?tid=7555
http://sciencemadness.org/talk/viewthread.php?tid=6617
http://sciencemadness.org/talk/viewthread.php?tid=2726
…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!
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smuv
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Ethyl Chloride Prep
This procedure is a re-worked methyl chloride preparation and has been adapted to yield ethyl chloride.
Reagents
30mL Ethanol
40mL 31.5% HCl
60mL H2SO4 (Drain cleaner)
The ethanol and hydrochloric acid were mixed in a 500mL rb flask, and cooled in an ice bath. The Ice bath was brought outside and the sulfuric acid
was added with the evolution of quite a lot of hydrogen chloride gas, even with slow addition. Next, everything was brought back inside, put on an
oil bath and setup for simple distillation with a 100mL receiver. The receiver was half filled with water and the outlet stem of the vacuum adaptor
was extended with pvc tubing so it lay just below the water in the receiver (to scrub HCl gas). To the outlet of the vac adaptor where one would
normally attach a vacuum pump, a piece of silicon tubing was affixed which connected to an efficient ice condenser.
(Condenser that was used to recover the ethyl chloride. It was made from 1/4" (ID) copper tubing and an old coffee can. The outlet of the spiral is
soft soldered to the wall of the coffee can)
(reaction flask and condenser)
(The EtCl condenser. The receiving test tube has an atmospheric vent and is sitting immersed in a basin of ice cold water)
The oil bath was gently heated, I unfortunately neglected to take any temp readings. During heating it was ensured that the contents of the 500mL
flask maintained a slow regular ebulation (nothing excessive) and that the receiver had constant flow of bubbles coming out of the extended vacuum
adapter stem. The hose from the vacuum adapter was periodically removed and the gas it was emitting cautiously wafted; this helped determine if ethyl
chloride was being produced (it smells like you may expect something like a milder chloroform) or if only ether was coming over. The whole operation
after setup took about 1.3 hours.
Note: After reading about the toxicity of ethyl chloride and knowing its history as an induction anaesthetic for a long span of time, the wafting
operation was judged to be safe.
Results
The yields were not great; I never quantified them but it looks like 2.5mL thereabouts. The recovered ethyl chloride burned with a characteristic
greenish-blue flame and emitted HCl gas. I think there was a lot of holdup in my condenser and if that got worked out yields would be better. A fair
bit of EtCl seemed to leave uncondensed, and sometimes condensed in and was pushed up the atmospheric vent tube. Also probably setting everything up
for reflux as opposed to distillation would increase yields, as unreacted ethanol/ether would not leave the reaction vessel; in retrospect I am not
sure what compelled me to setup for distillation.
(recovered EtCl...looks like some copper filings made their way over too.)
(Flame test. Performed by shaking ice cold test tube with my thumb over the outlet; after significant pressure built up my thumb was removed and the
effluent gas ignited.)
Conclusion
I am sure the yields for this method could be improved with subtle changes although may never approach those of the standard methods. I believe this
could be an efficient way of producing methyl chloride as methyls are more reactive via SN2 mechanisms.
@Nicodem
The only thread you posted that is pertinent to my question was the first one. In this thread 'Per' mixed hydrochloric acid with ethanol and
concentrated sulfuric acid and heated everything up; then stopped the operation because HCl gas was being produced; this hardly proved anything.
Maybe for you're reading.
Methyl Chloride prep from which this was adapted
US 2153170 Continuous RCl from ROH HCl + H2SO4
US 2091986
US 2091686 states: 'It is known that ethyl chloride may be produced by various procedures involving the use of ethyl alcohol as a starting material,
for example, by a batch process in which dilute sulfuric acid, sodium chloride and ethyl alcohol are heated together. According to such a process, the
ethyl alcohol and sulfuric acid are slowly introduced into a mixture of sodium chloride and dilute sulfuric acid, and the ethyl chloride evolved is
passed through a reftux condenser which prevents the alcohol from escaping unchanged from the reaction vessel. This type of process has the
disadvantage that a considerable time, generally about forty to fifty hours, is required to finish one batch.'
[Edited on 26-7-2008 by smuv]
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