- Carbonyl group is C=O. Has higher BP than hydrocarbons and ethers, and lower FP than alcohols.
- Aldehydes have the carbonyl group.
- R—CHO.
- Polar due to the oxygen (very electronegative).
- Can form hydrogen bonds with water, but cannot form intermolecular h-bonds to “itself” (other molecules of self).
- Can’t h-bond to aldehydes and ketones.
- Lower boiling point than alcohols.
- Has stacking potential.
- Naming saturated aldehydes: determine the longest chain containing the carbonyl; —e changes to —al; carbonyl carbon gets lowest number; number and name the rest of the substituents.
- Naming unsaturated aldehydes: the parent name goes from —ane to —enal; carbonyl carbon gets lowest number; and the rest follows the other unsaturated hydrocarbon rules.
- If the aldehyde or ketone has the hydroxyl and/or amine group then the hydroxyl substituent gets called hydroxy— and the amine group gets called amino—.
- Special carbon designation: the first adjacent carbon attached to the carbonyl carbon is the alpha carbon; the secondmost adjacent carbon is the beta carbon; the third-most is the gamma carbon; the fourth-most is the delta carbon.
Common Species to Know
Formaldehyde (methanal). H—CHO. BP -21 degress C. Disinfectant and tissue fixative/preservative agent.
Ethanal (acetaldehyde).
