Carbonyl compounds
Aldehydes and ketones are collectively known as carbonyl compounds.
General formula of aldehyde is given below where –CHO is the functional group
General formula of ketone is given below where –C=O is the functional group
Since carbonyl group is common for aldehyde and ketones, they are collectively known as
carbonyl compounds.
The carbonyl carbon of aldehyde is a terminal carbon always bonded to one “H” atom. The
carbonyl carbon of ketone is never a terminal carbon since it must be bonded to two other
“C” atom.
Ketones in which both the “R” groups are same are called “Simple ketones”.
Ketones in which two “R” groups are different, called “Mixed ketones”.
, Nomenclature
Aldehyde
Formula Common name IUPAC name
HCHO Formaldehyde Methanal
CH3CHO Acetaldehyde Ethanal
C2H5CHO Propionaldehyde Propanal
CH2=CH-CHO Acrolein/Acraldehyde Propenal
Benzaldehyde Benzaldehyde
Ketones
Formula Common name IUPAC name
CH3COCH3 Acetone Propanone
CH3COC2H5 Ethylmethyl ketone 2-Butanone
Cyclohexanone Cyclohexanone
Acetophenone Phenylethanone
Benzophenone Diphenylmethanone
Structure and Reactivity of Carbonyl group
The carbonyl carbon is sp2 hybrid and linked to 3 other atoms by “σ” bond. These bonds are
situated in a plane at about 120˚ apart.The remaining p orbitals of carbonyl carbons overlaps
sideways with p-orbital of oxygen to form a weak “π” bond. In other words, “C” and “O” of a
strong “σ” bond and a weak “π” bond.The M.O picture of aldehyde and ketones, is given
below:
Aldehydes and ketones are collectively known as carbonyl compounds.
General formula of aldehyde is given below where –CHO is the functional group
General formula of ketone is given below where –C=O is the functional group
Since carbonyl group is common for aldehyde and ketones, they are collectively known as
carbonyl compounds.
The carbonyl carbon of aldehyde is a terminal carbon always bonded to one “H” atom. The
carbonyl carbon of ketone is never a terminal carbon since it must be bonded to two other
“C” atom.
Ketones in which both the “R” groups are same are called “Simple ketones”.
Ketones in which two “R” groups are different, called “Mixed ketones”.
, Nomenclature
Aldehyde
Formula Common name IUPAC name
HCHO Formaldehyde Methanal
CH3CHO Acetaldehyde Ethanal
C2H5CHO Propionaldehyde Propanal
CH2=CH-CHO Acrolein/Acraldehyde Propenal
Benzaldehyde Benzaldehyde
Ketones
Formula Common name IUPAC name
CH3COCH3 Acetone Propanone
CH3COC2H5 Ethylmethyl ketone 2-Butanone
Cyclohexanone Cyclohexanone
Acetophenone Phenylethanone
Benzophenone Diphenylmethanone
Structure and Reactivity of Carbonyl group
The carbonyl carbon is sp2 hybrid and linked to 3 other atoms by “σ” bond. These bonds are
situated in a plane at about 120˚ apart.The remaining p orbitals of carbonyl carbons overlaps
sideways with p-orbital of oxygen to form a weak “π” bond. In other words, “C” and “O” of a
strong “σ” bond and a weak “π” bond.The M.O picture of aldehyde and ketones, is given
below:
