Chapter 18 Ketones and Aldehydes

Carbonyl Compounds

Ketone: 2 R groups (alkyl groups)

Aldehyde: 1 R group (alkyl group)

Carbonyl Strucutre

Main things to know is that the carbon is Sp2 hybridized, the C=O bond is polar with the O being more electronegative than the C

• carbon given partial pos charge with resonance structures

Ketone Nomenclature

Alkane —> Alkanone

• butane —> buta-#-one

  • the # is where the cabron the ketone’s oxygen is attached to

Aldehyde Nomenclature

Alkane —> Alkanal

• numbering done based on the carbonyl carbon closest to the end

• the aldehyde group is given the number 1

Ketone Substituents Nomenclature

If part of the long carbon chain —> writen as oxo group (3-oxopentanal)

If not part of the longest carbon chain —> writen as oyl group (2-pentanoylbenzoic acid)

Aldehyde Substituents Nomenclature

If part of the longest chain —> oxo group

If not part of the longest chain —> formyl group

Boiling Points of ketones and aldehydes

More polar than alkanes and ethers —> higher bp than them

Can’t form H-Bonds to each other —> Lower bp than alcohol

BP ranking order: Alcohol > Ketone & Aldehydes > Esters > Alkanes

Solubility of Ketones and Aldehydes

Good solvent for alcohols

• dissolve well in water —> oxygen’s lone pair of electrons can form hydrogen bonds with O-H or N-H

  • bonds with water

• small ketones & aldehydes (acetone and acetaldehyde) are miscible are mix with water completely

Ketones & Aldehydes Syntheses

Alcohol has to be oxidized to become either ketone or aldehyde

With NaOCl/ HOAc —> Ketones

With PCC or NaOCl (TEMPO present) —> Aldehyde

Alkene Ozonoloysis

Ozonolyisis: O3 used to form ketones and aldehydes from alkenes

Friedel-Crafts Acylation

Aromatic Ring + Cl-Cl-ACl3 —> para ortho positions ketones