Aldehydes and ketones are the carbonyl compounds with general formula CnH2nO. Aldehydes have at least one hydrogen atom bonded to the carbonyl group and other group is either hydrogen or an alkyl or aryl group (i.e. Aldehyde has one alkyl or aryl group and one of the hydrogen bonded to the carbonyl carbon) with characteristics functional group -CHO.

1. ALDEHYDEAND KETONE
P.M. Jadhav
Assistant Professor
Dept. of Chemistry
M.S.P. Mandals, Shri Muktanand college,
Gangapur, Dist. Aurangabad.

2. Aldehydes and ketones
Aldehydes and ketones are the carbonyl compounds with general formula
CnH2nO. Aldehydes have at least one hydrogen atom bonded to the carbonyl
group and other group is either hydrogen or an alkyl or aryl group.
Aldehyde has one alkyl or aryl group and one of the hydrogen bonded to the
carbonyl carbon with characteristics functional group -CHO.
In ketones, the carbonyl group is bonded to a two alkyl or aryl groups with –
CO- functional group. The two groups bonded to a ketone may be similar or
different resulting in a symmetrical or an unsymmetrical ketone.
C
O
R H
Aldehyde
C
O
R R'
Ketone

3. Nomenclature ofAldehydes and Ketones
Systematic names for aldehydes are obtained by replacing suffix -e of the
corresponding alkane by prefix –al i.e. aldehydes are named as alkanal. The
carbonyl carbon of the aldehydes is assigned 1 position.
Systematic names for ketone are obtained by replacing suffix -e of the
corresponding alkane by prefix –one. I.e. ketones are named as alkanone. The
position of carbonyl group in the ketone is assigned by the number.
Formula Compound Common name IUPAC name
CH2O HCHO Formaldehyde Methanal
C2H4O CH3CHO Acetaldehyde Ethanal
C3H6O CH3CH2CHO Propionaldehyde Propanal
C4H8O CH3CH2CH2CHO Butaraldehyde Butanal
Formula Compound Common name IUPAC name
C3H6O CH3-CO-CH3 Acetone Propanone
C4H8O CH3CH2-CO-CH3 Ethyl methyl ketone Butanone
C5H10O CH3CH2-CO-CH2CH3 Diethyl ketone 3-pentanone
C5H10O CH3CH2CH2-CO-CH3 Methyl propyl ketone 2-pentanone

4. Preparation Methods
1. Rosenmunds reaction(Reduction of acid chloride):The reduction of acid chloride
in presence of palladium supported catalyst like palladium on BaSO4 or Charcoal to
give product aldehyde.
2. Gatterman Synthesis: Preparation of aromatic aldehyde by the reaction of phenol
ether and HCN in presence of Lewis acid catalyst AlCl3 or ZnCl2 to give product
substituted aromatic aldehyde.
R C
O
Cl H2
Pd / BaSO4
R C
O
H HCl
Acid chloride Aldehyde
OCH3 OH
HCN
AlCl3
HCl
CHO
NH4Cl
Methoxy benzene
p-methoxy benzaldehyde

5. 3. Gatterman- Koch Reaction: The reaction involves formation of aromatic
aldehyde by the reaction of carbon monoxide and hydrochloric acid in presence of
Lewis acid (AlCl3) as catalyst.
4. Ketone from Nitrile or cyanide: Ketone prepared from Grignard reagent and
nitrile. The Grignard reagent attack on electrophilic carbon of nitrile to give a imine
salt which on hydrolysis to gives ketone.
5. Ketone from Carboxylic acid: The calcium salt of carboxylic acid on heating to
gives ketone.
Benzene
AlCl3
HCl
CO
CHO
Benzaldehyde
R C N
Nitrile
R'-Mgx
H2O
R C
O
R'
Ketone
R C
O
R CaCO3
R C
O
O
Ca
OC
O
R
Heat

6. 6. Oxidation of alcohols: Oxidation of Alcohols with oxidizing agents such as
potassium permangnate (KMnO4), K2Cr2O7/H2SO4, chromic acid or MnO2 to give a
carbonyl compounds aldehyde and ketone.
7. Ozonolysis of alkenes: Ozone reacts with alkene to form ozonide intermediate
which on treatment with reducing agent to gives aldehydes this reaction is called
ozonolysis.
Ethanol
K2Cr2O7
H2SO4
H3C CH2 OH H3C C H
O
Acetaldehyde
K2Cr2O7
H2SO4
H3C CH CH3
OH
2-Propanol
H3C C CH3
O
Acetone
HC CHR R O3
Zn dust
H2O
R CHO2.
Alkene Aldehyde

7. Chemical Reactions
1. Formation of acetals: Aldehydes and ketones react with two molecules of
alcohols to give geminal diether is known as acetal. The ketone derivatives are
known as ketal.
2. Oxidation of Aldehyde and ketone: The presence of hydrogen atoms in
aldehydes make easily to oxidized to carboxylic acids containing the same numbers
of carbon atoms with a oxidizing agents like chromic acid, chromium trioxide. The
silver oxide (Ag2O) in aqueous ammonia solution (Tollen’s reagent) is mild reagent
give good yield at room temperature.
Aldehyde
C
O
HH3C
C2H5OH
CH
OH
OC2H5H3C
Hemi-acetal
C2H5OH
CH
OC2H5
OC2H5H3C
Acetal
Ketone
C
O
CH3H3C
C2H5OH
C
OH
OC2H5H3C
Hemi-ketal
C2H5OH
C
OC2H5
OC2H5H3C
Ketal
CH3 CH3
C
O
HH3C
Acetaldehyde
CrO3 C
O
OHH3C
Acetic acid

8. 3. Reduction of aldehyde and ketone: The reduction of aldehydes to primary
alcohol and ketones to secondary alcohol in presence of reducing agents likes
LiAlH4, NaBH4 etc.
4. Knoevenagel Reaction: The condensation of aldehyde or ketone having no α-
hydrogen with active methylene compound in presence of weak base to give
unsaturated compound is known as Knoevenagel reaction.
C
O
HH3C
Acetaldehyde
LiAlH4
Dry ether / H2O
H3C CH2 OH
Ethanol
C
O
CH3H3C
Acetone
H3C CH
2-propanol
OH
CH3
NaBH4
CH3OH
C
O
HH3C
Acetaldehyde
CH2(COOH)2
Base
H3C CH
OH
CH
COOH
COOH H3C CH CH COOH
-CO2
-H2O
Malonic acid Crotonic acid

9. 5. Aldol Condensation: Aldehydes having α-hydrogen atoms which undergo
reaction in presence of base alkali to give codensation product β-hydroxy aldehyde is
known as aldol and the reaction is called aldol condensation. The ketones also
undergo condensation reaction to give product aldol of ketone.
Self-aldol condensation: The aldol condensation when two same aldehydes or
ketones molecule having α-hydrogen atom condensed is known as self-aldol
condensation.
Cross-aldol condensation: The aldol condensation when two different aldehydes
or ketones molecule having α-hydrogen atom condensed is known as cross-aldol
condensation.
C
O
HH3C
Acetaldehyde
2.
NaOH H3C CH
OH
CH2 CHO
Aldol
2.
NaOH
C
O
CH3H3C
Acetone
H3C C
OH
CH2 C
CH3
O
CH3
C
O
HH3C
Acetaldehyde
H3C CH
OH
CH2 CHO
Aldol
C
O
HH3C
Acetaldehyde
NaOH
H3C CH2 C
O
H
Propionaldehyde
C
O
HH3C
Acetaldehyde
NaOH
H3C CH
OH
CH
CH3
CHO CH2 CH
OH
CH2H3C CHO

10. 6. Perkins Reaction: The aromatic aldehyde when react with aliphatic acid
anhydride in presence of sodium salt of acetic acid to give a product α,β-
unsaturated acid is known as Perkins reaction.
7. Mannich Reaction: The compound containing at least one active methylene
hydrogen atom condensed with formaldehyde and ammonia, primary or
secondary amine in the form of hydrochloride to give a product Mannich base (β-
amino carbonyl compound) is known as Mannich reaction.
Benzaldehyde
CHO
(CH3CO)2O
CH3COONa
CH CH COOH
Acid anhydride
Cinnamic acid
Heat
H C
O
H
Formaldehyde
C
O
CH3H3C
Acetone
C CH2H3C(CH3)2NH2Cl
C2H5OH
HCl
O
CH2NH(CH3)2Cl
Mannich base

11. 8. Baeyer-Villiger oxidation: Oxidation of ketone to ester in presence of peracid
or hydrogen peroxide is known as Baeyer-Villiger oxidation. The hydrogen
peroxide is commonly used. Other peracids used are peracetic acid, perbenzoic
acid, performic acid or m-chloroperbenzoic acid, etc.
9. Cannizzaro’s Reaction: Cannizzaro reaction is redox reaction in which two
molecules of an aldehyde with no α-hydrogen when reacted with base sodium
hydroxide undergo self-oxidation and reduction to produce an alcohol and the salt
of corresponding carboxylic acid.
C
O
CH3
Acetophenone
PhCOOOH
Perbenzoic acid
O C
O
CH3
Phenyl acetate
CHCl3
H C
O
H H C
O
ONa
NaOH / KOH
Formaldehyde
H C
O
H
Formaldehyde
CH3OH
Methyl alcohol Sodium formate

12. 10. Benzoin Condensation: The benzoin condensation is a coupling reaction of
two molecules of aromatic aldehyde with no α-hydrogen in presence of potassium
cyanide in ethanol as catalyst to give product Benzoin (α-hydroxy ketone) is known
as benzoin condensation.
11. Reformatsky Reaction: The reaction of carbonyl compound like aldehyde and
ketone with α-haloester in presence of zinc in inert solvent ether to give β-
hydroxyester this reaction is known as Reformatsky Reaction.
C
O
H
Benzaldehyde
C
Benzoin
CN,
C
O
H
Benzaldehyde
C
H
OHO
EtOH, H2O
Heat
CR H
O
Aldehyde
Br CH2 COOR
Haloester
Zn, Ether
H3O
CH2 COORC
H
OH
R
B-Hydroxy ester
CR R'
O
Ketone
Br CH2 COOR
Haloester
Zn, Ether
H3O
CH2 COORC
R'
OH
R
B-Hydroxy ester

13. 12. Meerwin-pondorf-verly reduction (MPV): The reduction of carbonyl
compound like aldehyde or ketone in presence of aluminum alkoxide and isopropyl
alcohol to give product corresponding alcohol is known as Meerwin-pondorf-verly
reduction. The reduction of aldehyde gives primary alcohol whereas ketone gives
secondary alcohol.
13. Clemmensen Reduction: When aldehyde or ketone heated with zinc amalgam
and hydrochloric acid to gives corresponding alkane. The reaction in which the
reduction of carbonyl group into a methylene groups (-CH2-) this reaction is known
as Clemmensen reduction.
Acetaldehyde H3O
CH3C H
O
H3C CH2 OH
Al(iso-OPr)3 /
iso-PrOH
Ethanol
CH3C CH3
O
H3O
Al(iso-OPr)3 /
iso-PrOH
CHH3C
OH
CH3
Acetone Propanol
Acetaldehyde
CH3C H
O
H3C CH3
Ethane
Zn-Hg
HCl
H2O

14. 14. Wittig Reaction: The reaction of phosphorous ylides with carbonyl
compound aldehyde or ketone to give alkene is known as Wittig reaction.
Phosphorus ylide is from by the reaction of triphenylphosphine and alkyl halides
in the presence of strong base. The phosphorous ylides react with aldehyde or
ketone to give a betain as intermediate which further eliminates
triphenylphosphine oxide to give alkene.
R CH2 X Ph3P Ph3P CH2 R X
Phosphonium saltAlkyl halide Triphenyl
phosphine
Base
Ph3P CH R
Phosphorous ylides
Ph3P CH R

15. Thank You