[MrHappy0]

Hey!

I am an undergrad chem student that is currently finishing up my second semester in orgo 2. As I am passing through my textbook and trying to remain entertained, I came across the synthesis of an Ethers. I'm often wonder how easy it would be to synthesize compounds with very little background and such.

So ...How easily could someone like me synthesize diethyl ether using Acid Ether Synthesis?

You can buy H2SO4 and Denatured Ethanol, right? Then all you would need to do is heat the solution under 150 and form your product. Can you buy ethanol that isn't denatured? The subject of denaturing ethanol is confusing as well.

I am just curious how realistic this is. I don't plan on performing this but it was just a nagging curiosity that I couldn't let escape me. So spread the knowledge!

Yes, I understand that diethyl ether is very dangerous (peroxides, flammability).

[voidSetup]

Denatured alcohol means it contains additives that make it poisonous and undrinkable.  Otherwise people would have to pay liquor taxes on it.

[MrHappy0]

Thank you VoidSetup. I did know that methanol was added due to its toxicity but can you buy ethanol that is pure?

What are some ways a typical chemist might purify denatured ethanol?

[voidSetup]

I think they choose methanol because it has a similar boiling point as ethanol, so it can't be removed by simple distillation.  I'm not really sure how one could go about purifying denatured alcohol, but I think that some manufacturers do sell pure ethanol for very delicate work.

[Honclbrif]

Just run the acid-catalyzed ether formation. Dimethyl ether and methoxyethane are gasses at RT and would escape but the diethyl ether could be condensed.

[orgopete]

So ...How easily could someone like me synthesize diethyl ether using Acid Ether Synthesis?

This is what makes me skeptical. For anyone asking the question, it is cheaper to buy than to make. So, why would anyone want to or worry about synthesizing diethyl ether? And then, why would they ask about making PURE diethyl ether?

[voidSetup]

Yea it definitely does seem weird, I've seen other people ask this same question on these boards.  Why would anyone want to synthesize something that is typically used as a solvent and is cheap to buy?

[BobfromNC]

Thank you VoidSetup. I did know that methanol was added due to its toxicity but can you buy ethanol that is pure?

What are some ways a typical chemist might purify denatured ethanol?

The entire point of denaturing ethanol is to make it very difficult to repurify such that you cannot divert it for drinking.  95% ethanol is actually quite inexpensive to make ($4 a gallon or less for use in fuels), but if you could buy it in the liquor store it would cost $50 or so with taxes.   It is easier to ferment sugar/grain and distill it that to purify denatured alcohol.   Home brewers make ethanol all of the time.  That is a great home experiment in biochemistry which is safe and easy.  (Note, may be illegal if you are under 21...)  Distilling that beer to get higher purify ethanol is also a good challenge, since it requires several theoretical plates of distillation to get near the azeotrope of ~96%.

As for making diethyl ether, it is not nearly as easy to make in small quantities as the textbooks imply, just like not all Grignards work as well as the textbooks say.  It is far easier to buy ether than make it.   There are many chemicals which can be made industrially by methods that are not suitable for small scale, due to high temperatures, pressures, catalysts, need for inert atmosphere, and other logistical issues.   

[MrHappy0]

Wow, all very informative answers. I would probably be able to help educate someone on the subject if they asked me about it.

VoidSetup- Ah, derp move. I didn't think about how they have similar boiling points.
Honclbrif- Very cool.

orgopete, VoidSetup- Many people might ask about the synthesis of diethyl ether for the following reasons: (1) it can form peroxides (explosives), and (2) diethyl ether was once used as a general anesthetic. So it has interesting applications to the real world. This helps some people stay interested in chemistry. Although it is interesting, I would never attempt to synthesize the compound. Pure curiosity!

[408]

orgopete, VoidSetup- Many people might ask about the synthesis of diethyl ether for the following reasons: (1) it can form peroxides (explosives), and (2) diethyl ether was once used as a general anesthetic. So it has interesting applications to the real world. This helps some people stay interested in chemistry. Although it is interesting, I would never attempt to synthesize the compound. Pure curiosity!

Man, you guys....you have a question-asker on the defensive here...

ether is pretty innocuous(just don't let fumes build up, massive fire risk).  I distilled it at home from denatured ethanol and conc. sulfuric draincleaner when I was 15 or so.  Because chemistry is fun!

[orgopete]

@Mrshappy0, no problem. I read it pretty much as follows…

A friend of mine has this problem…

Since I don't know you (and you don't know me), that was how I took it. Granted the post said, "I don't plan on performing this…", but if you read it as I did, I wondered. It definitely was not asking, "How easily will it form peroxides or at what concentration will it put you to sleep if you try to synthesize it?"

The forum gets many kinds of questions. I read the original post again and seemed like a question about how to synthesize diethyl ether on your own. I did not think this was a question about what it can be used for.

[manofohm]

Diethyl ether can actually be a rather complicated synthesis certainly not safe on the small scale. You want rather large reactors to do this due to the large headspace as pressure builds up easily when adjusting ethanol flow to heated sulfuric acid producing ethene gas. The extra headspace also leads to a purer starting product to purify much less water and ethanol carried over. Generally speaking if you are not used to running at least a 22 L reactor or larger on the daily basis you probably dont want to try this synthesis unless you like ruined chem equipment and sulfuric acid/ ethanol/ ether mix all over your work space.

Crushed silica is a far greater boiling surface for the reaction. i believe it is do to the large size of the chips vs sand as sand will form a black gum like coating over its top while the silica chips have lots of large gaps for the goo to deposit through before it has a smooth serface which ether cannot boil from. basically more serface area on the large scale also on the microscopic scale to.

A large unpacked column (4 ft or more) is helpful along with the increased headspace... The ethanol returns to the reactor for rereaction and the water only makes it over as the azeotrope. Also this is safer more room for gases when pressure builds up and also if the reaction gets to vigorous sulfuric acid **** wont taint the product.

Nothing will do except a large alhin condensor, I really mean this. 3 ft minimum. If you try this with a straight condensor you wont condense all your ether and you may leave your lab looking like nagasaki.

Parts of this reaction are extremely exothermic while others are endothermic. It all really depends on the water and ethanol concentration in your reactor. if there is less than a certain ammount of ethanol you will increase your heat substantially by addition and of course ounce you cross over this certain ammount your reactor will cool by addition.

As for using denatured ethanol as far as I know most companies use a mixture of about 30-60 % methanol this would not do as dimethyl ether and diethyl ether will probably mix together and form a lower boiling azeotrope not condensable as I know dimethyl ether is no where even close to a liquid at roomtemp.

At the end of the process you are left with a rather blackened sulfuric acid/ethanol/water/ether mix. This is not good for much in the lab and certainly no good for the environment so do a favor for everyone on the planet and nutralize your waste. A small investment in a 5 dollar bag of hydrated lime (55 pounds) from your local home improvement store can do many gallons of sulfuric acid. Watch out this is extremely exothermic and can be dangerous but better than dumping that stuff down the drain.

There really is so much to the safe and ethical synthesis of ether that I simply cannot explain it all in a forum it deserves an article of its own(I am sure many exist) as there are so many factors to it. This is an incredibly dangerous, nasty synth and I highly recomend against it for anything but someone who has more than a few years of experience dealing with the glassware.

Forgive my choice to not use spell correct on this post as I am a chemist not an english teacher