Can you tell me why ketones and aldehydes don't bond with hydroxyl groups?
I posted earlier but no one has answered , common I am sure there is a wizard out there, I keeep looking but can not locatethe amswer.Thanks so much
Are you asking about a chemical reaction between aldehydes/ketones and alcohols? If so, they do react to form (hemi)acetals) and (hemi)ketals.
Are you asking about hydrogen bonding? That involves the attraction between a hydrogen in a H-O- group and an O in a different H-O- group. You are more likely to get an answer if you give us some context for your question.
sorry that is the question that was asked of me
Certainly! Ketones and aldehydes do not typically bond directly with hydroxyl groups because they lack a reactive hydrogen atom that is necessary for the formation of a hydrogen bond with the hydroxyl group.
To understand this, let's first take a look at the structure of a ketone and an aldehyde. A ketone has a carbonyl group (a carbon double-bonded to an oxygen) in the middle of a carbon chain, while an aldehyde has a carbonyl group at the end of a carbon chain.
The oxygen in the carbonyl group is electronegative, meaning it attracts electrons more strongly than the carbon atoms. As a result, the oxygen gains a partial negative charge, and the carbon in the carbonyl group gains a partial positive charge. This creates a polarized bond between the carbon and oxygen atoms.
Now, in order for a ketone or an aldehyde to bond with a hydroxyl group (-OH), a hydrogen bond needs to be formed between the oxygen of the carbonyl group and the hydrogen of the hydroxyl group. However, for this hydrogen bond to occur, the presence of a reactive hydrogen atom attached to the carbonyl carbon is essential.
In ketones, the carbonyl group is surrounded by alkyl groups, which do not have reactive hydrogen atoms. Similarly, in aldehydes, the reactiveness of the hydrogen atom on the carbonyl group is significantly decreased due to electron withdrawal from adjacent groups. As a result, there is no available hydrogen atom on the carbonyl carbon to form a hydrogen bond with the hydroxyl group.
It is worth noting that there are exceptions to this generalization. Certain ketones and aldehydes, like α-hydroxyketones and α-hydroxyaldehydes, do have neighboring hydroxyl groups that enable intramolecular hydrogen bonding.
I hope this explanation helps clarify why ketones and aldehydes typically do not bond directly with hydroxyl groups.