Ethyl ether can react with cold concentrated H2SO4?

[xcube]

I wonder if ethyl ether can react with cold concentrated H2SO4. I think that it cannot react but I still not sure because my books don't say anything about temperature condition. What about heated concentrated H2SO4, can it react without water or alcohol just only conc. sulfuric acid. Thank you for your kindness to answer these question.

 

[chem_tr]

Hello,

I'm not sure if the acidity of sulfuric acid is enough to achieve any hydrolysis; but it can be sufficient to protonate the oxygen to form an oxonium cation.

Hot concentrated H₂SO₄ is dangerous; it can produce high thermal energy to create a fire hazard, since diethyl ether is very flammable. But I don't think it even cleaves R-O-R bonds, it is because the remaining sulfate anion after protonation of ethereal oxygen is a very weak base.

Regards
chem_tr

 

[movies]

Sulfuric acid is strong enought to protonate an ether (pKa around -10 vs. pKa around -3.5 for a protonated ether). That should be enough to activate an ether towards hydrolysis, but like chem_tr said, I doubt the sulfate ion is a good enough nucleophile to cleave the ether bond. If you had a better nucleophile then it might happen though.

 

[chem_tr]

Movies: If you protonate an ether and expect it to undergo hydrolysis, you will only get its "deprotonated", I mean, original form. This is what I think, I may be wrong of course.

We may use peroxy acids to insert one more oxygen next to the ethereal one; and after cleavage, we may obtain some alcohol from the ether.

As a last suggestion, since ethers can be produced by dehydration of alcohols, some "activated" form of water, or a very strong base in the presence of radicalic mechanisms could be efficient in the cleavage.

 

[GCT]

With sulfuric acid, I imagine you would obtain a mixture of products, however predominantly, you would obtain corresponding alcohols as a result of the cleavage of the ether, with sulfuric acid, perhaps a carbocation would be formed (with a side product of alcohol) and this would react with nucleophilic water. Remember that in reality we are not limited to one route, other routes may take place.

With HCl, however, the major product is the corresponding alcohol (as a result of acid catalyzed cleavage) with an alkyl halide, which will react again with water to the product alcohol (reaction concentration dependent.

You need a certain amount of water for acid catalyzed reaction to take place, otherwise the ionization of the acid will not occur substancially


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[movies]

Hydrolysis of a protonated ether would give two alcohols, no? Similar to what GCT wrote. I don't know if you can obtain H2SO4 that is completely devoid of water, so I would think that hydrolysis would be a posibility.

You guys do raise an interesting point though: in theory the strongest acid that can exist in an aqueous solution is protonated water ("hydronium"), which has a pKa of -1.74, and wouldn't be powerful enough to significantly protonate an ether.

I honestly don't know what would happen in this case.