Aldehydes and Ketones. Before you can learn about aldehydes and ketones, you must first know something about the nomenclature of carboxylic acids since many of the names of aldehydes and ketones are derived from the names of the corresponding carboxylic acids. Carboxylic acids:
Before you can learn about aldehydes and ketones, you must first know something about the nomenclature of carboxylic acids since many of the names of aldehydes and ketones are derived from the names of the corresponding carboxylic acids.
HCO2H formic acid L. formica ant
CH3CO2H acetic acid L. acetum vinegar
CH3CH2CO2H propionic acid G. “first salt”
CH3CH2CH2CO2H butyric acid L. butyrum butter
CH3CH2CH2CH2CO2H valeric acid L. valerans
CH3(CH2)4CO2H caproic acid L. caper goat
CH3(CH2)6CO2H caprylic acid
CH3(CH2)8CO2H capric acid
CH3(CH2)10CO2H lauric acid oil of lauryl
δ γ β α used in common names
“carbonyl” functional group:
Aldehydes, common names:
Derived from the common names of carboxylic acids;
drop –ic acid suffix and add –aldehyde.
Parent chain = longest continuous carbon chain containing the carbonyl group; alkane, drop –e, add –al. (note: no locant, -CH=O is carbon #1.)
“alkyl alkyl ketone” or “dialkyl ketone”
Derived from common name of carboxylic acid, drop –ic acid, add –(o)phenone.
Parent = longest continuous carbon chain containing the carbonyl group. Alkane, drop –e, add –one. Prefix a locant for the position of the carbonyl using the principle of lower number.
polar, no hydrogen bonding
mp/bp are relatively moderate for covalent substances
(except: four-carbons or less)
IR: C=O stretch, strong ~1700 cm-1
RCHO 1725 ArCHO 1700
R2CO 1710 ArCOR 1690
C—H stretch for aldehydes 2720
nmr: -CHO 9-10 ppm
a b c d e
-4 -2 0 +2 +4
CH4 CH3OH H2C=O HCO2H CO2
alkane alcohol aldehyde carboxylic acid
RCH2-OH + K2Cr2O7, special conditions RCH=O
RCH2-OH + C5H5NHCrO3Cl RCH=O
[With other oxidizing agents, primary alcohols RCOOH]
Aromatic aldehydes only!
Aromatic ketones (phenones) only!
acid chloride + ArH
acid chloride + R2CuLi
cyclohexanone, 4-bromobenzaldehyde, 2-pentanone, valeraldehyde, acetophenone, isobutyraldehyde, using a different method for each one.