H-bonding

[bajoneswadup]

Ok so ethers can H-bond right? Obviously they can't donate a proton for the bond, but in general, if a question asks whether an ether can H-bond, the answer is yes right? (EK said they could).. AAMC9 had a question about MTBE (polar aprotic solvent), and MTBE is an ether so I put yes, but the answer was no. This makes sense because its polar APROTIC, but where do I draw the line???!!!! helppp

basically, how do I know when to put "yes ethers can H-bond" vs "no ethers
cant H-bond"? should I assume ethers can NOT H-bond at all times?

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[pfaction]

I had this exact same problem too. Link to the topic.

 

[chiddler]

Hbond with each other? No. Hbond with Hbond-capable molecules? yes very little because they can donate lone pairs for Hbonding.

 

[pfaction]

Hbond with each other? No. Hbond with Hbond-capable molecules? yes very little because they can donate lone pairs for Hbonding.

Click my link. I posted a pic of the question, cross posting here.

It never asks between itself, it asks between WATER. And I am 1000% sure ethers can hydrogen bond with water, because R-O-R + 2 H-X -> 2 RX + H2O.

 

[chiddler]

but i haven't taken that exam yet

 

[chiddler]

crap....

is it cheating if you tell me what the general idea is?

(WITHOUT REVEALING THE QUESTION!)

 

[kasho11]

it is safe to assume on the mcat that ethers can't hydrogen bond

 

[pfaction]

You already read the question and the answer, so...uh...

You should duck out of this topic before you read any more.

ethers can't hydrogen bond

Seriously please explain to me why. This question ^ kept me from getting a 14 on my AAMC9.

 

[chiddler]

You already read the question and the answer, so...uh...

You should duck out of this topic before you read any more.



Seriously please explain to me why. This question ^ kept me from getting a 14 on my AAMC9.

i didn't read anything from the image you posted. anyway sure i'm out of here.

 

[kasho11]

Because oxygen is bound to two carbons there is little polarization compared to a oxygen-hydrogen bond. It can essentially be thought of as an alkane. There is very little intermolecular interaction and can be thought of as essentially non-polar and insoluble in water.


And also you can look at experimental data, ethers have the lowest boiling point of all the functional groups, they are only above alkanes, indicating very few intermolecular forces.

 

[bajoneswadup]

Because oxygen is bound to two carbons there is little polarization compared to a oxygen-hydrogen bond. It can essentially be thought of as an alkane. There is very little intermolecular interaction and can be thought of as essentially non-polar and insoluble in water.

wait, what? mtbe is polar aprotic, so it's polar right? i mean, i know ethers are insoluble in water, thats why people use diethyl ether because its soluble with organic solvents, but how is a chiral ether like mtbe not polar?

 

[Jamie561]

wait, what? mtbe is polar aprotic, so it's polar right? i mean, i know ethers are insoluble in water, thats why people use diethyl ether because its soluble with organic solvents, but how is a chiral ether like mtbe not polar?

You guys are missing the point. mtbe is minimally soluble in water because of its hydrophobic moieties. Ether or not, polar or not, it won't easily mix with water.

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[bajoneswadup]

You guys are missing the point. mtbe is minimally soluble in water because of its hydrophobic moieties. Ether or not, polar or not, it won't easily mix with water.

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you mean hydrophillic? ugh im so confused now lol

 

[kasho11]

Hydrophobic - water fearing, hydrophilic - water loving

 

[Jamie561]

you mean hydrophillic? ugh im so confused now lol

Nope I meant hydrophobic


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