Antwain
Hazard to Others
Posts: 252
Registered: 21-7-2007
Location: Australia
Member Is Offline
Mood: Supersaturated
|
|
A puzzle... what do you get when you reflux conc. H2SO4 iodine and ethanol?
Ok I just lost 10+ minutes of typing and I cant be arsed typing it again. In short.
for reasons that don't really matter I ended up refluxing ~ 20g I2, 30mL conc. H2SO4 and 50mL ethanol.
At first I smelled something sweet and not diethyl ether nor iodoform so I decided to keep refluxing it. I think it may have been ethyl iodide but I
cant see how. It smelt *vaguely* like ethyl chloride
The flask atmosphere was iodine vapor and the condenser was running brown and yellow (iodine in ethanol coloured) but then started also running
colourless immisable droplets with a decent surface tension perhaps similar to water's or a bit more.
When I smelt the vent at the top of the condenser the sweet smell was still there weakly but so was a pungent smell like HCl (as opposed to say H2SO4,
HNO3 or H3PO4 which I can easily tell apart by smell) So obviously I was thinking it was HI even though you cant get it by KI + H2SO4, since that
wasn't even close to what I was doing  .
It *was* blue to wetted congo red paper stuck next to the vent.
Also when I turned the heat off (since now it wasn't a game... I was losing iodine) I noticed that the colourless drops were *very* quickly blackening
the moment they hit the different coloured atmosphere at the flask / condenser junction so that by the time they hit the liquid they looked like
iodine.
Any explanations, comments, questions welcome!
Actually, while I think about it... what the hell could I have made that is not soluble/ miscible with ethanol, that is if it was ethanol that was
refluxing (it was low surface tension and viscosity)
|
|
|
Sauron
International Hazard
Posts: 5351
Registered: 22-12-2006
Location: Barad-Dur, Mordor
Member Is Offline
Mood: metastable
|
|
Possibilities:
ethyl iodide - very low boiling and volatile, not so good for you to breathe
ethyl sulfate (diethyl sulfate) or ethyl hydrogen sulfate
Higher boiling and also not so wonderful for you to breathe.
There is certainly not a prayer you got anything containing chlorine but you know that.
So why did you not fractionate, noting the vapor temperature(s) and collecting the fractions? You would have then had b.p. and density information
available or at least accesible, also refractive index if a refractometer were handy. In any case a lot more than your unreliable (and vulnerable)
olfactory sense.
Your receiver should be chilled in ice-brine and your condenser water very cold (or use a dewar condenser) if you want to collect volatile alkyl
halides.
Apart from Et2O there isn't much else likely to come out of that pot. If I had to pick a single most likely product I'd say EtI with the acid acting
as a (Lewis acid) catalyst; the 80 C reflux temp (bp ethanol) is not really high enough for either of the sulfates or ether to form very efficiently.
But you could get a mix of 2, 3, 4 possible products.
What you might do is look up the prep of ethyl iodide and see whether or not the H2SO4 had a role to play or not
Likewise for the two possible ethyl sulfates. My recollection is that the ethyl hydrogen sulfate is used to flavor brandy (cognac essence) while the
diethyl sulfate is a potent alkylating agent, and carcinogen although less virulent than dimethyl sulfate (simply because its payload is larger) but
still nothing you want to be intimate with. In short USE A HOOD and do NOT try to inhale, try NOT to smell.
|
|
|
woelen
Super Administrator
Posts: 7976
Registered: 20-8-2005
Location: Netherlands
Member Is Offline
Mood: interested
|
|
The colorless non-miscible liquid could be the sulfate or hydrogen sulfate ester of ethanol: CH3CH2-O-S(O)2-OH or CH3CH3-O-S(O)2-O-CH2CH3
I'm not really sure about the miscibility properties of these esters with ethanol, but it *could* be.
Did you use denatured ethanol, or pure? Denatured contains MEK and it also contains some sweet-smelling chemical (at least, where I live). This also
could interfere and cause partial reduction of iodine.
|
|
|
Sauron
International Hazard
Posts: 5351
Registered: 22-12-2006
Location: Barad-Dur, Mordor
Member Is Offline
Mood: metastable
|
|
Ethyl iodide bp 72 C not as low as I thought. But definitely will volatilize out of ethanol.
Diethyl sulfate is bp 209.5 and is miscible with ethanol, practically insol in water, and hydrolyzed rapidly by hot water to ethyl hydrogen sulfate
and ethanol.
But your mix contained no water
Merck gave no bp for ethyl sulfate (ethyl hydrogen sulfate) which is odd. I will look elsewhere.
Usual catalyst for prep ethyl iodide same as methyl iodide, red phosphorus.
If you want to REALLY be perplexed see the following entry from Merck:
: Oil of Wine, "Heavy".
Literature references:
An oily liq obtained by distilling alcohol or ether (or both) with sulfuric acid. Constit. Etherin and etherol (C 2 H 4 ) n , polymers of ethylene;
eth yl sulfate and ethyl sulfovinate. Properties: Colorless to slightly yellow liq; penetrating odor; sharp, bitter taste. d 15 15 1.095-1.130 .
Almost insol in water; misci ble with alcohol, ether. Density: d 15 15 1.095- USE: For making ethereal oil which is used in making Hoffmanprimes
anodyne; sometimes for flavoring brandy.
Good thing I had to give up booze as I would not care for any ethyl sulfate in my brandy!
Now I have to look up "ethereal oil" and "Hoffman's anodyne"...
Still no bp for ethyl hydrogen sulfate
Ethereal sirits and Hoffman's anodyne are archaic 18th and 19th century anaesthesia materials. There's a formula buried on this page about UC Civil
War surgery:
http://www.braceface.com/medical/Civil_War_Articles/Union_me...
if anyone is interested enough to dig it out.
Anyway the point is that complex things happen when you reflux or distill ethanol and sulfuric acid, a lot more complex than ethyl sulfates, ether,
and ethylene.
Etherin is supposed to be a white crystalline hydrocarbon polymer of ethylene (C2H4)n which is obtained by heating "heavy oil of wine" (see above)
Etherol is supposed to likewise be a polymer of ethylene, but liquid so perhaps of lower MW.
So far I have not tracked down the identity of ethyl sulfovinate.
HOWEVER, I doubt that this refluxing got anywhere neat the 140 C ether-making temperature. Or did it?
Normally to do that you heat the H2SO4 to that point and then add ethanol at same rate that ether comes over. Not a recommended practice at home, for
obvious fire hazard reasons, and to be undertaken even in a proper lab with suitable precautions.
[Edited on 12-9-2007 by Sauron]
|
|
|
evil_lurker
National Hazard
Posts: 767
Registered: 12-3-2005
Location: United States of Elbonia
Member Is Offline
Mood: On the wagon again.
|
|
You can't boil ethyl hydrogen sulfate (at least at atmospheric pressure) because it all turns into ether.
As far as the I2, well most of it should have sublimated.. I would think it would not react although there may have been some free radical action
going on from ambient light.
God only knows what the hell you made... most likely a mess if I am correct.
Not all chemicals are bad. Without chemicals such as hydrogen and oxygen, for example, there would be no way to make water, a vital ingredient in
beer.
|
|
|
Sauron
International Hazard
Posts: 5351
Registered: 22-12-2006
Location: Barad-Dur, Mordor
Member Is Offline
Mood: metastable
|
|
I am puzzled by the logic of doing this at all without any effort to collect and characterize what was produced. I mean, what was the point if that
was not done?
@evil, point taken but at least some approx decomposition point ought to be known, or a bp at a reduced pressure.
So far I have found lots of vendors of diethyl sulfate but none of ethyl sulfate or ethyl hydrogen sulfate. I am still looking, just to try to nail
down the physical constants. Very frustrating.
|
|
|
The_Davster
A pnictogen
Posts: 2861
Registered: 18-11-2003
Member Is Offline
Mood: .
|
|
Silver nitrate in aqueous acetone should determine if what you got is ethyl iodide.
I got this from my qualitative organic ananylsis book, which I will cite when I find it on my bookshelf. As well as the precise procedure.
[Edited on 12-9-2007 by The_Davster]
|
|
|
Sauron
International Hazard
Posts: 5351
Registered: 22-12-2006
Location: Barad-Dur, Mordor
Member Is Offline
Mood: metastable
|
|
Ethyl sulfate IS sulfovinic acid CAS [540-82-9]
d 1.46
bp and mp unknown!
Live and learn...
|
|
|
Antwain
Hazard to Others
Posts: 252
Registered: 21-7-2007
Location: Australia
Member Is Offline
Mood: Supersaturated
|
|
There is a lot to add / address / explain here. Firstly, I did not intend to do anything except make anhydrous iodine.
It was pack up time so I have done nothing further. At one point, when the 'stuff' to be vague about what exactly was not being fully condensed, early
in the attempt, the iodine was molten in the flask, and i would swear by the deep blue colour in the flask that a large proportion was a gas, but I
couldn't maintain this level of heating as very occasional bumping blew iodine (plus other stuff, maybe) out the top. There was, only barely visible,
purple iodine vapor making it up the tube... It occasionally poked above the brown/yellow thin film of liquid flowing back down the condenser, causing
the brown level to rise.
I haven't smelt any ethyl sulfates (not that I really want to) but there was *no* ether there. You guys have every right to not trust my sense of
smell but I am certain. Also there was an acid, and a volatile one, since non volatile aerosoled acids mist much more than this was (ie. not at all).
I haven't charactorised it because separating the AT LEAST 4 different things not present (or present at reflux) would be difficult. I am still
debating just dumping it in lots of water to recover my iodine, but probably wont until I have solved this. Would the hydrolysis of EtI give HI? Is
this possible?
Its late and I cant think anymore  . When I get up tomorrow I will do....
something.... and get back to you with the results
|
|
|
Sauron
International Hazard
Posts: 5351
Registered: 22-12-2006
Location: Barad-Dur, Mordor
Member Is Offline
Mood: metastable
|
|
It wasn't YOUR sense of smell I was dissing, it was anyone's, for the purpose of identifying unknowns.
You did not by any chance have a thermometer in the liquid or in the vapor did you?
Not sure what you mean by anhydrous iodine. Your I2 was wet? And you wanted to dry it? What's wrong with a dessicator and some dessicant like
magnesium sulfate? Or Drierite?
|
|
|
Dr. Beaker
Hazard to Others
Posts: 132
Registered: 9-9-2005
Location: between the med red and dead
Member Is Offline
Mood: Shaken, not stirred
|
|
sulforic acid can oxidize methane to methanol at elevated temp., with I2 being known as a catalyst in this reaction (see patent). maybe you oxidized
ethanol to ethylene glycol, which is itself sweet (but poisoness) and has sweet smeling fumes. what you smelled is some of its vapors or vapors of the
glycol esters\ethers.
Bjerrum N.J., Xiao G., Hjuler H.J., 2002, Process for catalytic oxidation of hydrocarbons, US Patent #
6,380,444
I2 can also be oxidized by SO3 to I+HS2O7- which opens a rather interesting cat. cycle of oxidation of methane to methyl bisulfate
http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArtic...
and finally - I2 can be reduced by SO2 in the presence of water (alcohol will also do I guess) to produce HI and H2SO4 (or sulfate ester)
[Edited on 13-9-2007 by Dr. Beaker]
|
|
|
Sauron
International Hazard
Posts: 5351
Registered: 22-12-2006
Location: Barad-Dur, Mordor
Member Is Offline
Mood: metastable
|
|
Fine except that EG would not survive in hot sulfuric acid, there were neither SO3 nor SO2 present. So none of those are likely IMO.
It was conc H2SO4 not fuming.
But nice try.
----------------------
*Heavy Oil of Wine"
One part of conc H2SO4 is sufficient to catalyze the conversion of ethanol to 200 parts ether. At that point the buildup of water renders the acid too
dilute to continue efficiently.
After all the ether has come over, if the temperature of the spent acid is raised, "Heavy Oil of Wine" is what comes over. It is a yellowish liquid
with a sharp odor and density 1.06 to 1.12. It is principally ethyl sulfate aka sulfoviniv acid, along with some diethyl sulfate or ethyl
sulfovinate. The sulfovinate/sulfovinic nomenclature is now obsolete or at least very obsolescent, usually only encountered in older literature.
Besides the ethyl and diethyl sulfates, the remainder of the variable mixture seems to be the presumed polymeric ethylenes referred to in the older
lit. as etherin (solid) and etherol (oily liquid) both (C2H4)n and etherin presumablt the higher MW of the two.
Ethyl sulfate is industrially important as intermediate in the production of synthetic ethanol from ethylene and H2SO4.
Diethyl sulfate is an alkylating agent and suspected carcinogen.
I am going to check in Ullmann and Kirk-Othmer to see if the modern lit. has anything further to say about etherin and etherol, but they are really
not all that interesting if they are just low MW PE.
[Edited on 13-9-2007 by Sauron]
[Edited on 13-9-2007 by Sauron]
|
|
|
Dr. Beaker
Hazard to Others
Posts: 132
Registered: 9-9-2005
Location: between the med red and dead
Member Is Offline
Mood: Shaken, not stirred
|
|
both SO2 and SO3 can occure in heated conc. H2SO4:
H2SO4 <---> H2O+ SO3 ΔS<0, ΔH>0
SO3 <----> SO2 + 1/2O2 ΔS<0, ΔH>0
SO2 is also a common reduction product of SO3\H2SO4
I guess he got (among other things) HI ("acidic smell") that distilled of with some H2O, and when the 2 condensed and got back to the solution it was
oxidized by H2SO4 or SO3 to I2 and water ("darkening of the clear liquid").
|
|
|
Sauron
International Hazard
Posts: 5351
Registered: 22-12-2006
Location: Barad-Dur, Mordor
Member Is Offline
Mood: metastable
|
|
Yes, I was about to correct my criticism along these lines. In the sulfuric acid process for ether, H2SO4 can oxidize ethanol to acetaldehyde and
release SO2, it's a minor side reaction. The resulting acetaldehyde needs to be purified out of the EtO product.
I really hate to rely on his descriptions of smells, and in absence of temperature info it is really hard to make any meaningful guesses. The
ether-making reaction ought not to have happened below 125 C and that temperature ought never to have been reached as long as the ethanol was in
there, and the system under reflux, unless the heating was wild and crazy and a lot of various things were being lost out of the top of the reflux
condenser. THAT is not reflux. That is distillation without bothering to condense product.
But your surmise about HI is as likely as anything else and more likely than some others.
Ullmann says the industrial sulfuric acid process for ether is rigorously held to 125-130 C and starting at a ratio of 1 part ethanol to 3 parts acid,
can run for months (more ethanol being run in) before the acid needs to be changed. At which point the acid is full of tar-like byproducts.
|
|
|
The_Davster
A pnictogen
Posts: 2861
Registered: 18-11-2003
Member Is Offline
Mood: .
|
|
To determine if it is halogen contaning using alcoholic silver nitrate: FromSystematic Identification of organic compounds: A laboratory
manual Shriner and Fuson, 3rd edition, 1948.
Alcoholic silver nitrate:
| Quote: |
This reagent is usefull for classifying compounds known to contain halogen. Add one drop of the halogen compound to 2mL ofa 2% ethanolic silver
nitrate solution. If no reaction is observed after 5 min standing at room temperature, heat the solution to boiling and note whether a precipitate is
formed. If there is a precipitate, note its colour. Add 2 drops of dilute(5%) nitric acid, and note whether the precipitate dissolves. Silver
halides are insoluble in dilute nitric acid, wheras silver salts of organic acids are soluble |
|
|
|
Antwain
Hazard to Others
Posts: 252
Registered: 21-7-2007
Location: Australia
Member Is Offline
Mood: Supersaturated
|
|
Ok, unless someone else wants to try this on a small scale then I think that its going to remain a mystery. I refluxed the solution up an air
condenser then into a water condenser. Just as the steam temperature was starting to rise above ambient and a VERY small amount of iodine + solvent
that dissolved it yellow was starting to come across all of a sudden the most potent smell of SO2 I have ever had the mispleasure of smelling
appeared. I shut down the heating immediately. Dont tell me this may have not been SO2. It damn well was. I had to come in and have ventolin because
it started to produce asthma symptoms. In 10 minutes when its aired out I may go back down and run some tests on the mL of distillate, but theres no
point testing for halogen since there is iodine there. I may stick some pH paper into it.
This is an utter pain. Now that I cant get anything out by heating I will have to neautralise it, dissolve the iodine in base, get most of the sulfate
out, and then acidify whats left. leaving me once again with wet iodine. Just so you know, the iodine was coming across at well below its boiling
point, but anyone who has worked with it before knows that even though it has a very low vapor pressure at room temp It has a nasty habit of both
volatilising and not condensing.
Also, while I was setting up the apparatus, the sweet smell was very prevalent.
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
