aldehydes and ketones?

Question

I need to know what the purpose is of checking the acidity of carbonyl compounds is, can anyone help?

Answer 1

You question has to do with keto - enol isomerization:

C=0 + H+ --> +C-O-H

If you protonate carbonyl group (ketone or aldehyde) is can isomerize it the enol form. If it does then the reactivity of the carbonyl become more like the character of a carbocation that a carbonyl, and a number of things can happen which you may, or may not want to happen to the carbonyl group - like rearrangement, reaction with a nucleophile or elimination of water with the solvent to form an alkene.

Answer 2

1

Answer 3

Because under acidic conditions the carbonyl group is likely protonated and therefore less reactive to whatever reactions you are trying to do as a carbonyl.

Answer 4

REACTIVITY:
Protons in acidified solutions are electrophiles;
the electronegative oxygen reacts with electrophiles.
Perhaps the purpose of checking the acidity of carbonyl compounds
is to see if the O is tied up with an H and therefore LESS reactive/
MORE stable than O alone. Possibly, if acidic they keep better.

Answer 5

Aldehydes can be oxidised by the air and turn to carboxylic acids.

If you do a pH test and you get an acid its an aldehyde in the bottle not a ketone.

Answer 6

they are more reactive under acidic conditions as they will be pronated (the will have a few hydrogens attached to them) it is best to keep them in alkaline or even neutral conditions