Carboxylic acid to acid chloride = oxidation?

[ilzmastr]

Is a Carboxylic acid going to an acid chloride an oxidation reaction or a reduction?

You lose an H, and an O, so which is it?

---

Members don't see this ad.

 

[MedPR]

Is a Carboxylic acid going to an acid chloride an oxidation reaction or a reduction?

You lose an H, and an O, so which is it?

Neither? If anything it would be reduction since the carbon is bound to an oxygen in the carboxylic acid (and not a hydrogen).

 

[CodeRedDew]

I would classify it as a reduction because you lose a C-O bond for a C-Cl bond.


Sent from my iPhone

 

[Godric]

i would classify it as a reduction because you lose a c-o bond for a c-cl bond.


Sent from my iphone

+1

 

[NonTraditional3]

Oxygen donates electrons through a single bond, withdraws through a double bond. Since Cl will withdraw electrons through a single bond, and the carbon now has a lower electron density, I would cast my vote and say that it is OXIDIZED.

 

[ilzmastr]

Oxygen donates electrons through a single bond, withdraws through a double bond. Since Cl will withdraw electrons through a single bond, and the carbon now has a lower electron density, I would cast my vote and say that it is OXIDIZED.

Terrifically clever clever!
Thanks for all the responses!

 

[NonTraditional3]

Also noteworthy to mention Cl- is more electronegative than -OH.

 

[MedPR]

Oxygen donates electrons through a single bond, withdraws through a double bond. Since Cl will withdraw electrons through a single bond, and the carbon now has a lower electron density, I would cast my vote and say that it is OXIDIZED.

 

[NonTraditional3]

Sorry! It's been a long day for me - those rules apply for EAS. BUT, I would still think if you are exchanging an OH for a Cl, that since Cl is more greatly electronegative, that it would oxidize the carbonyl carbon, no?

 

[MedPR]

Sorry! It's been a long day for me - those rules apply for EAS. BUT, I would still think if you are exchanging an OH for a Cl, that since Cl is more greatly electronegative, that it would oxidize the carbonyl carbon, no?

I subscribe to "lose an O/gain an H = reduced". I don't know about any relationship that exists between electronegativity and redox (not in this context, anyway).

 

[NonTraditional3]

We're going from RCOOH to RCOCl. The OP may be confused because the hydrogen that is lost is not directly attached to the carbonyl; it is attached to the oxygen. Since the oxygen withdraws electrons from the carbonyl carbon, it leaves the carbonyl carbon with a partially positive charge, compounding the effect of the doubly bonded carbon of the carbonyl. That being said, look at the electronegativity trends of the periodic table; Chlorine is more electronegative than oxygen, so the extent to which it will with draw electrons from the carbonyl carbon is greater than the effect of the oxygen from the hydroxyl group. If you can check out the formal charges of the carbon in the two structures - this should confirm that it is oxidized.

 

[MedPR]

We're going from RCOOH to RCOCl. The OP may be confused because the hydrogen that is lost is not directly attached to the carbonyl; it is attached to the oxygen. Since the oxygen withdraws electrons from the carbonyl carbon, it leaves the carbonyl carbon with a partially positive charge, compounding the effect of the doubly bonded carbon of the carbonyl. That being said, look at the electronegativity trends of the periodic table; Chlorine is more electronegative than oxygen, so the extent to which it will with draw electrons from the carbonyl carbon is greater than the effect of the oxygen from the hydroxyl group. If you can check out the formal charges of the carbon in the two structures - this should confirm that it is oxidized.

I understand what you're saying, I just don't know why chlorine being more electronegative implies oxidation.

 

[NonTraditional3]

I understand what you're saying, I just don't know why chlorine being more electronegative implies oxidation.

Less electrons around the carbon. The O in -OH and Cl- both only make a sigma bond with carbon, so it then, theoretically, should come down to the extent to which they reduce the e- density about the carbonyl carbon...

 

[MedPR]

Less electrons around the carbon. The O in -OH and Cl- both only make a sigma bond with carbon, so it then, theoretically, should come down to the extent to which they reduce the e- density about the carbonyl carbon...

Oh I see.

 

[NonTraditional3]

Now, does anyone here know what the substituent effect of a carbonyl is on benzene? Ortho, meta, or para directing?

 

[CodeRedDew]

Less electrons around the carbon. The O in -OH and Cl- both only make a sigma bond with carbon, so it then, theoretically, should come down to the extent to which they reduce the e- density about the carbonyl carbon...

A more electronegative atom doesn't reduce the number of electrons around the carbon. It just reduces the electron density (as you said) by changing the quantity of the dipole moment. A reduction in JUST electron density doesn't equate to an actual oxidation; I believe it has to be a reduction of an actual number of electrons.

Lastly, oxygen is MORE electronegative than chlorine. (remember FONClBrISCH)


Sent from my iPhone

 

[ilzmastr]

Now, does anyone here know what the substituent effect of a carbonyl is on benzene? Ortho, meta, or para directing?

A carbonyl group bonded to a benzene will be moderately deactivating meta directing.

If you mean an oxygen directly double bonded to a carbon on the benzene, well, that doesn't exist, but a single bonded oxygen with a negative 1 charge on it is strongly activating ortho/para

 

[NonTraditional3]

A carbonyl group bonded to a benzene will be moderately deactivating meta directing.

If you mean an oxygen directly double bonded to a carbon on the benzene, well, that doesn't exist, but a single bonded oxygen with a negative 1 charge on it is strongly activating ortho/para

Yeah, I meant like in benzaldehyde or benzoyl chloride, stuff like that...