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skeletal-clown
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Synthesis of Diethyl Ether
So I'm new here and haven't really experimented with organic chemistry much before (I have a fair amount of inorganic chemistry experience), and have
a few questions about the ethanol/H2SO4, synthesis of diethyl ether.
I plan to use OTC methylated spirits (95%+ w/v ethanol), home made (via electrolysis of CuSO4), concentrated sulfuric acid and a simple 24/29 ground
glass distilation set up on a sand or oil bath. I plan to follow a similar process to the one described in Vogel's Practical Organic Chemistry.
So I guess my questions are these:
1. I have no dropping funnel, would there be any problems with simply adding all the ethanol at the start of the reaction or pausing periodically,
cooling the setup and adding more ethanol?
2. My H2SO4 may have slight copper and/or lead impurities, I can't see how this would affect the reaction, but I am pretty new at this.
3. Are there any tips/pieces of advice you guys can offer?
Thanks in advance for any help!
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DrSchnufflez
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Look in the prepublications section for len1's detailed report on Diethyl ether synthesis.
However ether is not somthing that you make without the proper equipment, it is flammable, biologically active, readily forms explosive mixtures with
air and it has a very low boiling point so you need, at minimum a long Liebig with ice water running through it.
I would advise that, at minimum you buy an addition funnel.
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woelen
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I would not worry too much about the toxicity of ether (actually, it is very low), but I would worry very much about its flammability and very wide
range of concentration in which it can explode when mixed with air. The ignition temperature of ether also is quite low, a hot mantle could already
cause ignitiion if vapors are streaking against the heating element.
The boiling point is 34 C and you need very good cooling, otherwise most of the ether will escape as vapor from your distillation apparatus. I doubt
whether a Liebig cooler is good enough. Maybe you need a spiral cooler, which has a much longer travelling path for the vapors.
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skeletal-clown
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Firstly, thanks for your help.
A spiral cooler would certainly be preferable, but in the diagram included in Vogel's synthesis, a liebig condenser appears to be used (also, this is
all I have on hand). I plan to run it on salted ice-water and plus, it's winter here. My apparatus has a vacuum/vent outlet through which I plan to
scrub excess ether fumes.
I know using an addition funnel would be preferable, but is there any reason all the ethanol can't be added at once?
Diethyl Ether vapors are heavier than air and the heat source will be above any possible leaks.
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Lambda-Eyde
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I wouldn't worry about dying from diethyl ether poisoning either, but with poor ventilation I would worry about passing out in front of an apparatus
that needs a lot of attention.
Yes, there is. The reaction between diethyl ether and ethanol at high temperature can produce two different products depending on the conditions:
diethyl ether and ethylene. If you look up a lab prep of ethylene you will notice how similar it is to that of diethyl ether, but you will also note
the subtle differences.
As others have said, go look up len1's topic in the Prepublications forum. It is an absolutely fantastic post which will walk you through the
procedure step by step. If you only have a 20-30 cm liebig I would invest in a spiral condenser for this procedure. You will most certainly use it
again.
Also, winter in Australia? Meaning 12 degrees on a cold day? 
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DrSchnufflez
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Just to clarify by biologically active I meant its effects on consciousness 
In response to lambada-eyde yes, pretty much 12 degrees is accurate for victoria, Australia
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skeletal-clown
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Thanks again guys, I'm pretty new to this and your help is very much appreciated. I've found a rather well priced spiral condenser from a company I've
used before, but I can't seem to find a good (AKA, not to crappy and still cheap), addition/dropping funnel. Do you have any suggestions as to where
to buy one?
I've read through len1's post several times, It's been my other main reference in this procedure.
As for fumes, I plan to carry this out in a well ventilated/semi-outdoors area.
And yes, 12 degrees seems fairly typical here 
EDIT: I've been examining the H2SO4/ethanol production of ethylene, and besides the higher temperature, what else is different? So, I guess what I'm
asking, is what conditions favour the production of ethylene and which favour diethyl ether?
If what I've read is correct, I could exclude an addition funnel as long as I kept the temperature of the apparatus to 140 degrees.
[Edited on 29-5-2013 by skeletal-clown]
[Edited on 29-5-2013 by skeletal-clown]
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RobertRobinson75
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You probably want to keep it well below 140C otherwise you may still be producing some ethylene.
[Edited on 29-5-2013 by RobertRobinson75]
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Nicodem
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Please read a few procedures for this reaction. It should be then obvious to you, that it can not work if you add all the ethanol at once. The
required reaction temperature is claimed to be about 140 °C and the boiling point of ethanol is way lower.
…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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Magpie
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This brings up a philosophical point that often bothers me, ie,
One person will take the trouble to develop and write-up a procedure for synthesizing a given chemical. Then others, who wish to synthesize said
chemical, but do not have the necessary reagents or equipment, will come to the forum asking if some reagents, equipment, or steps can be substituted,
or even ignored! I always wonder if these people think that the procedure writers put these requirements in their procedures just for the fun of it,
or to make things difficult. It's as if they want all procedures to be reduced to just water, salt, and jam jars!
The single most important condition for a successful synthesis is good mixing - Nicodem
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Mailinmypocket
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LOL!
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chemcam
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This post should have been made under the write-up and I agree he should have known that you can't add all the ethanol at once but when it comes to
the equipment needed there are countless different setups that will get the job done. If you don't have an addition funnel think to yourself, "what
else could probably work?"
You can use a long stem funnel or thistle tube instead of an addition funnel in this procedure, but, it is more time consuming. Use a two-neck flask;
one neck goes to the condenser and the other just has a stopper, when the time comes to add more EtOH remove the stopper and insert the thistle tube
or long stem funnel. Simple as that.
If I were you though I would definitely invest in a addition funnel, LaboyGlass has very cheap, good quality addition funnels.
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skeletal-clown
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| Quote: | | You probably want to keep it well below 140C otherwise you may still be producing some ethylene. |
Alright, will do. I'll keep it at the lowest temperature possible while still having something condense.
| Quote: | | Please read a few procedures for this reaction. It should be then obvious to you, that it can not work if you add all the ethanol at once. The
required reaction temperature is claimed to be about 140 °C and the boiling point of ethanol is way lower. |
I have read through several procedures, both here on SM and in several text books. (The SM library is awesome by the way!). As I said, I've never
really done much work with organic chemistry so this is all very new to me, I'm learning as I go. I've been doing more research, and I now understand
why adding all the ethanol at once would not work (without a large excess of H2SO4), forgive me for asking a stupid question.
| Quote: |
This brings up a philosophical point that often bothers me, ie,
One person will take the trouble to develop and write-up a procedure for synthesizing a given chemical. Then others, who wish to synthesize said
chemical, but do not have the necessary reagents or equipment, will come to the forum asking if some reagents, equipment, or steps can be substituted,
or even ignored! I always wonder if these people think that the procedure writers put these requirements in their procedures just for the fun of it,
or to make things difficult. It's as if they want all procedures to be reduced to just water, salt, and jam jars! |
I would have you know that I am not one of these people. As I believe I've stated, I am wiling to buy new reagents and pieces of equipment when
necessary (i.e. the spiral condenser), although if money can be spared, I, like anybody else, would like to do so. Also, in some circumstances, said
write do have some steps which are able to be substituted or ignored. One piece of glassware can be swapped for another or a different reagent may be
used for a slightly poorer yield. Write ups are simply the author's method and not necessarily the only one. And of course I wouldn't "want all
procedures to be reduced to just water, salt, and jam jars!", that would take all the challenge and fun out of chemistry!
Well that sure contributed to the discussion.
| Quote: | This post should have been made under the write-up and I agree he should have known that you can't add all the ethanol at once but when it comes to
the equipment needed there are countless different setups that will get the job done. If you don't have an addition funnel think to yourself, "what
else could probably work?"
You can use a long stem funnel or thistle tube instead of an addition funnel in this procedure, but, it is more time consuming. Use a two-neck flask;
one neck goes to the condenser and the other just has a stopper, when the time comes to add more EtOH remove the stopper and insert the thistle tube
or long stem funnel. Simple as that.
If I were you though I would definitely invest in a addition funnel, LaboyGlass has very cheap, good quality addition funnels.
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Hi, I'm sorry if this is in the wrong section, I'm pretty new to the whole forum thing. As you can see, I have been considering other options to the
addition funnel ( | Quote: | | pausing periodically, cooling the setup and adding more ethanol? |
) And your suggestion of using a
two-necked flask is very useful, thank you. Wow, thanks for the link also, their prices are really good! I hope the shipping to Australia isn't too
much though Thanks again, you've been very helpful.
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testimento
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Could you make ether by distilling ethanol over Al2O3 catalyst bed at 900C?
According to
[^ Ethyl Ether, Chem. Economics Handbook. Menlo Park, Calif: SRI International. 1991.]
"Vapor-phase dehydration of ethanol over some alumina catalysts can give diethyl ether yields of up to 95%"
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Dr.Bob
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You might if you have an industrial, well engineered setup. Otherwise, you will more likely make a news headline, due to the fire that ensues.
Temperatures above 200C are not for home chemists unless they have some experience and a safe place to test the system (outside, away from their and
others houses).
Skeletal, I would give similar advice, please try this type of reaction outside first, not inside, as I have seen a number of ether fires, and they
are quite vigorous. Inside a fume hood, there is some safety, but doing something like this on a kitchen counter or inside, with limited
ventilation, there is easily the potential to build up enough vapors to ignite, and ether vapors burn like gasoline, and can ignite from any trivial
spark or even hotplate temperatures. So best to do this outside with a hose or fish water pump for the cooling water. Then, you 1) have better
ventilation and 2) if it catches fire, not as bad.
I have done similar work, and have seen a few good ether fires. They grow very quickly out of control.
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Lambda-Eyde
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Dr.Bob: garage chemist has experimented a lot with his home-built high temperature tube furnace. I think this experiment could be performed reasonably
safe with a well-constructed apparatus and proper precautions. Flushing with argon or nitrogen, good cooling, maybe flaring off the exhaust... It is
certainly doable for an experienced chemist.
This just in: 95,5 % of the world population lives outside the USA
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S.C. Wack
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Even if done with all precautions, without the missing details, it's most likely to result in many liters of ethylene. 900C and 95% sounds full of
specifics.
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Organikum
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Once I read an article I think it was posted even here by leu, which desribed the dehydration of EtOH by kind of solid acid catalyst made by soaking a
carrier with 70% H2SO4 at far lower temperatures in a heated tube. Less then 150°C IIRC far less. Good yields.
No time to search for it, sorry.
/ORG
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testimento
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U can flush the system with propane gas if you want, as long as it takes the oxygen out, it will prevent the detonation of aerosols. Indeed I was
thinking a system of pot that hold the alcohol where it is distilled and it goes into an insulated pot which is half full of aluminium oxide and under
it is strong burner to get the 900c in the pot, and then it would turn into ether and condense into the receiver funnel and flask. If ethylene is
produced in minor quantities, i still would consider any yield of over 60% of ether production from ethanol a success compared to the expensive and
hard to get sulfuric acid method. if you get ethylene you can vent it off or burn it or use it for other syntheses. I live in a totalitarian state
where the sale of chemicals is very highly restricted and state troopers raid people everyday for minor suspicions so i will need to make everything
myself, methanol sale is in total ban and even food alcohol cost 70 bucks a liter, luckily they havent banned sugar and yeast yet, haha. if ether can be made by distilling ethanol over alumina its a god bless for me,
removes one major pain in the ass of getting very important solvent.
[Edited on 25-6-2013 by testimento]
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starman
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@ Skeletal clown a couple of notes for you.
A peristaltic pump is superior to an addition funnel.(See my post in Len's thread). It gives you precise adjustable control and can be knocked up from
a couple of rollers and tubing for a few bucks.
Be careful of importing glassware. I don't know about Victoria but some states(mine included) have draconian laws in regard to owning glassware.You
can get 5 years for possessing a condenser.Be cautious when purchasing anything here.
Chemistry- The journey from the end of physics to the beginning of life.(starman)
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skeletal-clown
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@Starman
Thanks for your advice, the peristaltic pump idea seems quite promising, especially if I end up scaling up the procedure.
As for importing glassware, do you mind if I ask where you got that fact about condensers in WA? Before I started ordering glassware I did quite a bit
of research on it's legality in Australia and all the information I could find was quite ambiguous.
One of the best sources of information I managed to find was a thread made by another member here: http://www.sciencemadness.org/talk/viewthread.php?tid=14982
By the way, I haven't actually made any ether yet, but I recently ordered a large amount of equipment from Laboy (including a proper addition funnel
and a 400mm Graham condenser which I plan to run as a vertical second stage to my 300mm Liebig), for that and other purposes, thanks again everybody
for your help.
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starman
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@Skeletal clown regarding glassware restrictions and penalties WA see misuse of drugs act 2004 amendments.There is a thread with the links here
somewhere.Queensland is the same or worse,Victoria may be more liberal.
Regarding you setup, I used a horizontal leibig 90deg bend into a Graham vertical,with ice water in the graham and tap water in the leibig,worked a
charm.
You'll find it easy to maintain reaction temperature as with the right rate of addition it seems quite self regulating.
Btw I used methylated spirits straight from bunnings and it worked fine.
Apart from using the peri pump and capillary tube and omitting the sand I followed Len to the letter.
Good luck to you in your synthesis.
Found 1 thread
http://www.sciencemadness.org/talk/viewthread.php?tid=12978#pid164842[/url]
[Edited on 27-6-2013 by starman]
Chemistry- The journey from the end of physics to the beginning of life.(starman)
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skeletal-clown
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Oh wow, you're right. Queensland and WA seem rather....extreme. How ridiculous! By the way, I found Victoria's act and it seems MUCH less draconian at
least as far as glassware is concerned. http://www.austlii.edu.au/au/legis/vic/consol_act/dpacsa1981... or more specifically www.austlii.edu.au/au/legis/vic/consol_act/dpacsa1981422/s80...
Thanks for your advice though, I'm glad I'm in Victoria!
As for your apparatus, that sounds near identical to mine!
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starman
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Yeah lucky you. It seems in Victoria there is no law against possessing chemistry equipment whatsoever.(as there fucking well shouldn't be anywhere!)
The Victorian act seems to only call for EUD record keeping of suppliers.
As for me,I am in the unenviable situation of possessing a fairly well set up amateur lab and having to conduct everything on the down-low like I'm
some sort of criminal.
Maybe one day in this country we'll have something like a bill of rights to protect individual freedom on a national basis.
Chemistry- The journey from the end of physics to the beginning of life.(starman)
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skeletal-clown
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I hope so, the current legislation in most of the country is ridiculous!! These laws are simply blatant anti-intellectualism.
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