In organic chemistry, a carbonyl group is a functional group composed of a carbon atom double-bonded to an oxygen atom: C=O.
Method of preparation of Aldehyde and Ketone
3. DEFINATION
METHODS OF PREPARATION OF
ALDEHYDE AND KETONES
REACTIONS OF ALDEHYDE AND
KETONE
PROPERTIES OF CARBONYL
COMPOUNDS
CONTENTS
4. Carbonyl Group
In organic chemistry, a carbonyl group is a
functional group composed of a carbon atom
double-bonded to an oxygen atom: C=O.
5. Method of preparation of
Aldehyde and Ketone
1. Oxidation of alcohol
2. Catalytic dehydrogenation of alcohol
3. Oxidation of alkene
4. Hydration of alkynes
5. Hydrolysis of gem- dihalides
6. Reduction of acid chlorides
7. From nitriles using Grignard reagents
8. Oxo process
9. Pyrolysis of calcium salt of acid
10. Catalytic decomposition of acids
6. 1. Oxidation of alcohol
• Primary alcohol treated with potassium
dichromate to form aldehyde and secondary
alcohol to form ketone.
7. 2. Catalytic Dehydrogenation of
Alcohol
• Alkyl halide undergo reduction with nascent hydrogen in
presence of reducing agent like Zn/HCl to form alkanes.
8. 3. Oxidation of Alkene
• Oxidation of alkene by using ozone in presence of zinc to
form aldehyde or ketone
9. 4. Hydration of Alkynes.
• Acetylene on hydrolysis to form acetaldehyde and methyl
acetylene on hydrolysis to form acetone.
10. 5. Hydrolysis of Gem-Dihalides
• Gem dihalides on hydrolysis to form diols and further
dehydration of diol to form aldehyde or ketone
11. 6. Reduction of Acid Chlorides
Aldehydes can be prepared by the hydrogenation of acid
chlorides in the presence of palladium supported over barium
sulphate.
12. 7. From Nitriles using Grignard
Reagents
• A Grignard reagent attacks to nitrile to give the magnesium
salt of an imines. • Acid hydrolysis of the imines leads to
ketone
13. 8. Oxo Process
• Alkene react with hydrogen and carbon monoxide to form
aldehyde
14. 9. Pyrolysis of Calcium Salt of
Acid.
• Pyrolysis of calcium salt of dicarboxylic acid to give ketone
16. Reactions of Aldehyde and
Ketones
A) Nucleophilic addition reaction
1. Addition of water
2. Addition of alcohol
3. Addition of hydrogen cyanide
4. Addition of Grignard Reagants
C) Reduction of aldehyde and ketone
D) Oxidation of aldehyde and ketone
E) Reaction involving alpha hydrogen
1. Aldol condensation
2. Perkin condensation
3. Benzoin condensation
4. Canizzaro reaction
B) Addition- elimination reaction
• 1. Reaction with ammonia
• 2. Reaction with hydroxyl amine
• 3. Reaction with hydrazine
• 4. Reaction with phenyl hydrazine
• 5. Reaction with 2,4 dinitrophenyl hydrazine
17. A) Nucleophilic Addition Reaction
• Positively charged carbon is readily attacked by electron rich
nucleophile and negatively charged oxygen is attacked by
electrophile.
18. 1. Addition of Water
• Water can add to a carbonyl group to form a 1,1 diol called as
gem- diol or hydrate.
19. 2. Addition of alcohol
• Addition of alcohol to carbonyl group of aldehyde in presence
of strong acid to form hemiacetal and acetal.
• Addition of alcohol to carbonyl group of ketone in presence of
strong acid to form hemiketal and ketal.
20.
21. 3. Addition Hydrogen Cyanide
• Hydrogen cyanide can add to the carbonyl group of an
aldehyde or ketone to form cyanohydrins.
22. 4. Addition of Grignard reagents
• Aldehydes and ketones react with Grignard reagents to give an
addition product which can be hydrolyzed to give alcohol.
23. B) Addition- elimination
reactions
• Nucleophilic addition to carbonyl group followed by
elimination of water to form product containing a double bond.
24. 1. Reaction with ammonia
• Ammonia is a nucleophile that can attack a carbonyl group of
an aldehyde or ketone and product is imine.
25. 2. Reaction with Hydroxy amine
• Aldehydes and ketones react with hydroxylamine to form
oximes.
26. 3. Reaction with Hydrazine
• Aldehydes and ketones react with hydrazine (NH2-NH2) to
form hydrazones.
27. 4. Reaction with Phenyl Hydrazine
• Aldehydes and ketones react with phenylhydrazine to form
phenyl hydrazones
28. 5. Reaction 2,4 dinitro phenyl
hydrazine
• Aldehydes and ketones react with 2,4 dinitrophenyl hydrazine
to form 2,4 dinitrophenyl hydrozones.
29. C) Reduction of Aldehyde and
Ketone
• Reduction of aldehyde and ketone to form alcohol and
alkane
Reduction with lithium aluminium hydride or sodium
borohydride
Cont..>
30.
31. D) Oxidation of aldehyde and ketone
• Aldehydes undergoes oxidation in presence of sodium
dichromate to form carboxylic acid • Aldehydes and ketone
oxidized by Fehling's or benedicts or tollens reagent to form acid
and gives red ppt
36. Crossed aldol condensation
• If you react two aldehydes or ketones together in an aldol
condensation, you will get four products. However, if one of the
reactants doesn’t have any alpha hydrogens it can be condensed
with another compound that does have alpha hydrogens to give
only one organic product in a “cr
ossed” aldol
37. A crossed aldol can also be done between an aldehyde and a
ketone to yield one product. The enolate carbanion from the
ketone adds to the more reactive aldehyde.
38. 2. Perkin condensation
• Benzaldehyde react with acetic anhydride in presence of
sodium acetate to form cinnamic acid.
39. 3. Benzoin condensation
• The Benzoin Condensation is a coupling reaction between two
aldehydes that allows the preparation of α-hydroxyketones.
43. Crossed canizzaro reaction
• When the mixture of formaldehyde and non enolizable
aldehydes are treated with NaOH to form alcohol and formic
acid is converted into formic acid called as crossed cannizaro
reaction. • E.g. Benzaldehyde and formaldehyde is treated with
strong base to form benzyl alcohol and formic acid
44. Properties of Carbonyl Compounds
Some properties of carbonyl compounds are given below:
These are to be polar in nature. They exhibit both positive and
negative charge in slight form. Hence, these are said to be
polar molecules.
These compounds are reported to be insoluble in water but
sometimes they dissolve other forms of polar molecules.
These are known to be as chemically reactive compounds. It
means that they control the reactions of a chemical reaction.
