Presentation

Aldehydes & Ketones
Aldehydes are compounds having general formula
H
R
O R= H, CH 3 , C 2 H 5 , C 6 H 5 , etc…
C
Ketones are compounds having general formula
R
C
O
R R=CH ,C H , C H etc...
3 2 5
6 5
Slide 2
IUPAC names of Aldehydes
Formula
Common Name
IUPAC Name
Acetaldehyde
Ethanal
HCHO
Fomaldehyde
CH3CH2CHO
Propionaldehyde
CH3CHO
CH3CH2CH2CHO
(CH3)2CHCHO
Butyraldehyde
Isobutyraldehyde
Methanal
Propanal
Butanal
2-Methylpropanal
Slide 3
IUPAC names of Aldehydes
Formula
CH2=CH-CHO
CH3CH=CH-CHO
C6H5CH=CH-CHO
C6H5CHO
C6H4(OH)CHO
Common Name
IUPAC Name
Crotonaldehyde
But-2-enal
Acrolein
Cinnamaldehyde
Benzaldehyde
Salicyaldehyde
Prop–2–enal
3-Phenylprop-2-enal
Benzaldehyde
2-Hydroxybenzaldehyde
Slide 4
IUPAC Names of Ketones
Formula
CH3COCH3
CH3COCH2CH3
CH3CH2COCH2CH3
CH3COCH2CH2CH3
C6H5COCH3
C6H5COC6H5
Common Name
IUPAC Name
Ethyl methyl ketone
Butanone
Acetone
Diethyl ketone
Propanone
Pentan-3-one
Methyl propyl ketone Pentan-2-one
Methyl phenyl ketone or
Acetophenone
Diphenyl ketone or
Benzophenone
1-phenylethanone
Benzophenone
Slide 5
Structure of Carbonyl group

C



O
120
o
C
120
2
O
o
Sp - hybridised
The carbon- oxygen double bond is polarized due to higher
electro negativity of oxygen than carbon.
Hence
C
O
Electrophile
C+-O-
Nucleophile
Slide 6
From oxidation of primary and secondary alcohols
H
R
C
H
OH
OH
PCC
R
[O]
R-CH(OH)-R’
KMnO4/KOH
C
H
OH
R
C
O
+H2O
H
R-CO-R’ + H2O
Slide 8
By dehydrogenation of alcohols
H
R
C
OH
Copper
R
o
H
R-CH(OH)-R’
H
C
O + H2
300 C
Cu/573K
R-CO-R’ + H2O
Slide 9
From alkene by ozonolysis
R
CH
CH2 + O 3
R
CH
CH2
O
O
H
Zn
R
C
O + CH2O
H2O
O
Slide 10
From Acyl Chloride
By Rosenmund reduction
O
R
C
O
H2
Cl
R
C
H + HCl
Pd - BaSO4
o
140 C
Slide 11
From Nitrile by Stephen’s Reduction
SnCl2
R
C
R
N
+HCl
H
H2 O
CH
NH
R
H+
C
O
+ NH 3
Slide 12
Preparation of Benzaldehyde from
Toluene
Etard's Reaction
CH3
CrO2Cl2
CHO
+H2O
CS2
Slide 13
By Gattermann – Koch reaction.
C6H6 + CO + HCl Anh AlCl3/CuCl
C6H5CHO
Slide 14

Dry distillation of calium salts give aldehyde and ketones.
Calcium formate
Calcium formate and calcium acetate
– Formaldehyde
- Acetaldehyde
Calcium formate and calcium benzoate - Benzaldehyde
Calcium acetate
Calcium benzoate
Calcium benzoate and calcium acetate
- Acetone
- Benzophenone
Slide 15
- Acetophenone
From nitrile and Grignard reagent
R
C
-|
Dry
+
N R Mg x
R
Ether
R-MgX + HCN
X
2 H2 O
dry ether
C
R'
N. Mgx
R
H
C
+
R-CH=NMgX
O + NH 3
R'
H2O/H+
+ Mg
OH
R-CHO
Slide 16
Ketones from Acyl chloride and dialkylcadmium
2 R'
C
O
Cl + R 2Cd
2 R'
C
R + CdCl 2
O
Slide 17
Aromatic ketones from Benzene by Friedel – Craft
reaction
R
C
O
Anhydrous
C
AlCl3
O
Cl
R + HCl
Slide 18
Physical properties of Aldehydes and ketones
• Physical state: HCHO – Gas, Up to C13 are liquids and higher
ones are solids.
• Odour : Lower aldehydes have unpleasant odour where as
higher ones have pleasant odour.
• Boiling points: These compounds have higher boiling points
than ethers and hydrocarbons due to dipole interactions but
lower boiling points than that of alcohols due to the absence
of intermolecular hydrogen bonding.
Slide 19
Reactions of Aldehydes and Ketones
(i) Nucleophillic addition
a
b

C

Planar


O
+ Nu
slow
Nu
Nu
a
C
+
fast H
C
O
b
Tetrahedral intermediate
OH
a
b
Addition Product
Slide 20
Reactions of Aldehydes and Ketones
With HCN
Both aldehydes and ketones react with HCN to form addition
product Cynohydrin (in presence of a base)
HCN + OH


C
-
-
CN + H 2O


O
O
OH
C
C
CN
H+
CN
Tetrahedral
Intermediate
CN
Slide 21
Cyanohydrin
Reactions of Aldehydes and Ketones
With NaHSO3

C



O
O Na
+
+ Na SO
3
H
C
SO3H
Proton Transfer
OH
C
SO3Na
Bisulphite addition Compound
All aldehydes react with NaHSO3 to form a white crystalline
solid, bisulphite addition compound. Many ketones also react.
But acetophenone does not react with NaHSO3 due to stearic
hindrance.
Slide 22
Reactions of Aldehydes and Ketones
With alcohols
Only aldehydes react with alcohols in presence of dry HCl to
form acetals.
H
R
C
O
dry HCl
2 R'
OH
H
OR '
R C
+H 2 O
OR '
acetal
Slide 23
Reactions of Aldehydes and Ketones
With alcohols
Ketones react only with Ethylene Glycol to form cyclic product
R
C
R
O
H 2C
OH
H 2C
OH
dry HCl R
O
CH 2
+H 2 O
C
R
O
CH 2
Ethylene Glycol Ketal
Slide 24
Reactions of Aldehydes and Ketones
With ammonia derivatives
NH2 Z Where Z=OH, NH2, C6H5NH, NHCONH2 alkyl, aryl


C


O
OH
H2N
Z
C
C
NH
N
Z +H2O
Z
Slide 25
Reactions of Aldehydes and Ketones
• NH2-NH2
CH3CH=N-NH2
• NH2-NHC6H5
CH3CH=N-NHC6H5 Phenyl hydrozone
• NH2-OH
• NH2NHCONH2
CH3CH=N-OH
Hydrozone
Oxime
CH3CH=N-NHCONH2 Semicarbazone
Slide 26
Reactions of Aldehydes and Ketones
Mechanism



C

O
: NH2
O
H+ Transfer
Z
C
Z
-
N
OH
C
H
H
N-Z
H
Unstable
OH
C
N
H
Z
C
N
Z +H2O
Slide 27
Reactions of Aldehydes and Ketones
Oxidation:
Aldehydes readily get oxidized to give Carboxyacids
H
R
C
O
[O]
R
COOH
Na2Cr2O7 + H2SO4
Slide 28
Reactions of Aldehydes and Ketones
With Tollen’s reagent
H
R
C
+
O + 2[Ag(NH3)2] + 3 OH
-

RCOO + 2 Ag + 2H2O + 4NH3
Silver Mirror
Slide 29
Reactions of Aldehydes and Ketones
With Fehling solution
H
R
C
2+
O + 2Cu +5OH

RCOO + Cu2O +3H2O
Red ppt
Slide 30
Reactions of Aldehydes and Ketones
Oxidation of Ketones:
In presence of strong oxidising agents at high temperature
ketones get oxidized . Their oxidation involves C-C bond
cleavage. A mixture of Carboxylic acids having lesser number of
carbon atoms formed.
Ex: H3C
C
O
alkaline
CH3
KMnO4
4[O]
CH3COOH + CO 2 + H 2O
Slide 31
Reactions of Aldehydes and Ketones
Reduction: Aldehydes and Ketones are reduced to primary and
secondary alcohol by using LiAlH4 /NaBH4
H
R
C
LiAlH4
O
R
THF
C
H
O
R
R
THF
OH
Primary Alcohol
LiAlH4
R
CH2
C
R
OH
Secondary Alcohol
Slide 32
Reactions of Aldehydes and Ketones
Reduction to Hydrocarbons (Clemmensen reduction)
H
R
C
Zn - Hg
O
R
CH3 + H2O
R
CH2 R + H2O
Concentrated HCl
Zn - Hg
R
C
O
R
Concentrated HCl
Slide 33
Reactions of Aldehydes and Ketones
Wolf-Kishner reduction
H
R
C
H2N
NH2
O
R
CH3 + H2O
R
CH2
KOH/NaOH
R
C
O
R
H2N
NH2
KOH
R + H2O
Slide 34
Reactions of Aldehydes and Ketones
Reactive α- Hydrogen
The α-Hydrogen in aldehydes and ketones is acidic in nature. It
is due to the strong electron withdrawing
C
O group.
Slide 35
Reactions of Aldehydes and Ketones
Aldol condensation
H
H
H3C C O
acetaldehyde
H3C
C
H
dil NaOH
O
H3C
acetaldehyde
H
C
CH2
H
C
O


OH
H3C
CH
CH
C
O
But - 2 - enal
aldol
3 - Hydroxy butanal
O
O
H3C
C
CH3 H3C
C
OH
Ba(OH)2
CH3
H3C
C
O
O
CH2
C
CH3
CH3
Ketal
(4 - Hydroxy, 4 - Methyl Pentan - 2 one)


H3C
C
CH
C
CH3
CH3
4 - Methyl pent - 3en - 2 one
Slide 36
Reactions of Aldehydes and Ketones
Cross aldol condensation
Benzaldehyde + Acetophenone
OH
O
C
1,3-Diphenylprop-2-enone
OH-/ Δ
H
H3C
C
OH
C
O
Dil NaOH
H
CH2
C
-H2O
O

CH
CH C
O
1.3 . diphenyl Propzentone
Slide 37
Reactions of Aldehydes and Ketones
Electrophilic Substiution:
Aromatic aldehydes and Ketones undergo electrophillic
substitution to give meta- substituted product
H
C
O
H
Concentrated HNO3
C
O
Concentrated H2SO4
NO2
Metanitro benzaldehyde
Slide 38
Reactions of Aldehydes and Ketones
Cannizzaro’s reaction
(Reactions + Aldehydes which have no α – Hydrogen
H
2
H
C
KOH
50%
O
HCOOK + CH 3OH
Potassium Methanol
formate
H
2
C
O
COOK
KOH
50%
Potassium
Benzoate
CH2
Benzylaclohol
OH
Slide 39
Reactions of Aldehydes and Ketones
Uses(i) :Formaldehyde
In the manufacture of latex rubber.
Preparation of Formalin(40% solution for preserving biological
specimen), Trioxane , Bakelite(Thermosetting polymer) &
Urotropine(urinary antiseptic)
Uses(ii) : Acetaldehyde
In the preparation of acetic acid , ethyl acetate & vinyl acetate.
Paraldehyde(hypnotic) and metaldehyde(solid fuel)
Slide 40
Reactions of Aldehydes and Ketones
Uses(iii) : Benzaldehyde
Used in perfumery, dye industries
Used as flavoring agent
Used in the preparation of Cinnamic acid, Malachite green
Uses (iv) : Acetone
Used as industrial solvent
Used in the preparation chloretone(hypnotic), Mesityl oxide,
Phorone, Mesityline, chloroform and iodoform
Slide 41
Reactions of Aldehydes and Ketones
Uses (v) :Acetophenone
Used in the preparation of Tear gas phenacyl chloride
Used in the preparation of a hypnotic ‘Dypnone’
Slide 42
1. Which is the most suitable oxidising agent used to convert
primary alcohol into an aldehyde?
(a) Acidified K2Cr2O7
(c) Alkaline KMnO4
(b) Acidified KMnO4
(d) PCC
2. When PCC is used as an oxidising agent, which is the solvent
used?
(a) T.H.F
(c) Dichloromethane
(b) Diethyl ether
(d) Carbon disulphide
Slide 44
3. Which is the product obtained 2–Pentene undergoes
ozonolysis followed by treating with Zn + H2O?
(a) Acetone
(b) Acetaldehyde
(c) Propionaldehyde (d) Acetaldehyde and propionaldehyde
4. What is product formed, when vapours of acetic acid are
passed over heated MnO at 573K?
(a) Formaldehyde
(c) Acetone
(b) Acetaldehyde
(d) Acetic anhydride
Slide 45
5. What is the product formed when propyne is treated with
dilute H2SO4 in presence of HgSO4 catalyst?
(a) Propene
(c) Propanol
(b) Propanal
(d)Propanone
(d)
Propanone
6. Phenyl cyanide treated with SnCl2+ con. HCl and the product
formed treated with dilute acid gives
(a) Phenol
(c) Benzaldehyde
(b) Benzoic acid
(d) Benzyl alcohol
Slide 46
7. CH MgI + A
3
H2 O
Dry Ether
B
H
+
CH3CHO
In this, reactant A is
(a) CO2
(b) H3C
C CH3 (c) HCN
O
(d) CH3OH
Slide 47
8. In the reaction
CHO
Anhydrous
+CO + HCl
+HCl
AlCl3
which is the electrophile?
(a)
CO
(b) CHO
(c) Cl
(d)
CHO
Slide 48
9. A dihaloalkane on alkaline hydrolysis produces a ketone with
formula C3H6O. The compound is
(a) 1,2-Dichloropropane
(c) 2,2-Dichloropropane
(b) 1,1-Dichloropropane
(d) 1,3-Dichloropropane
10. Which one of the following is present in the blood of
diabetic patient?
(a) Methanol
(c) Propanone
(b) Ethanoic acid
(d) Propanal
Slide 49
11. 3-Pentanone and 2-Pentanone are
(a) Metamers
(c) Functional isomers
(b) Chain Isomers
(d) Optical isomers
12. In aldol condensation the intermediate formed is
(a) Carbonium ion
(c) Carbene
(b) Nitrene
(d) Enolate ion
Slide 50
13.The product formed when Benzaldehyde is treated with
acetaldehyde in presence of dilute NaOH is
(a) Benzyl alcohol
(c) Benzoic acid
(b) Ethanol
(d) 3–Phenyl prop-2-enal
Slide 51
14.
CH3 MgI + A
NH2 - NH2
Dry
B
Ether
KOH
Propane
Identify A in the above reaction.
(a) Acetone
(c) Formaldehyde
(b) Acetaldehyde
(d) Ethane nitrile
Slide 52
15. Haloform reaction is given by the compounds having
(a) CH2 – OH group
(c) – COOCH3 group
(b) – COOH Group
(d)
O
C
CH3
16. Acetaldehyde and Benzaldehyde differ in reaction with
(a) Tollen’s Reagent
(c) NaHSO3
(b) HCN
(d)Dilute NaOH
Slide 53
17. Dypnone, a hypnotic is obtained from
(a) Acetone
(c) Acetophenone
(b) Acetaldehyde
(d) Benzaldehyde
18. Phenacyl Chloride prepared from acetophenone is used as
(a) Polymer
(c) Lachrymater
(b) Antioxidant
(d) Antiseptic
Slide 54
19.Which one of the following statements is wrong?
(a) Aldehydes and ketones are good reducing agents.
(b) Aldehydes and ketones are polar compounds.
(c) Aldehydes are more reactive than ketones.
(d) Aldehydes and ketones are reduced to alcohols.
Slide 55
20.
H2O 70 oC
R
C
(a) R
C
H
C
O
H
(b)
H2SO4 +HgSO4
R
C
O
CH3
A A is
(c) RCOOH
(d) R
CH2
OH
21. Both formaldehyde and acetaldehyde give similar reactions
with all the reagents except
(a) Schiff reagent
(c) Ammonia
(b) Tollen’s reagent
(d) Fehling solution
Slide 56
22. In the Cannizzaro’s reaction, the slowest step is
(a) Attack of OH on Carboxyl group
(b) The transfer of Hydride ion to the Carboxyl group
(c) Removal of H+ from COOH
(d) Attack of H+ on Carboxyl group
23. C2H5CHO and
H3C
C
O
(a) Phenyl hydrazine
(c) Sodium bisulphate
CH3
can be distinguished using
(b) Hydroxyl amine
(d) Fehling solution
Slide 57
24. Acetophenone is converted into Ethyl benzene by using
(a) NaBH4
(c) Sodium + Alcohol
(b) LiAlH4
(d) Zn–Hg + Con. HCl
25. In Rosenmund reduction the role of BaSO4 is
(a) Catalyst
(b) Prometer
(c) To absorb the heat evolved
(d) To decrease the activity of catalyst palladium
Slide 58
26.
H
H3C
C
LiAlH4
O + H2N
Here B is
(a) CH3CH2OH
(c) CH3CH=N – OH
OH

A
B
(b) CH3CN
(d) CH3 – CH2 – NH2
Slide 59
27. Crossed aldol condensation is not given by
(a) Acetaldehyde and Acetone
(b) Acetaldehyde and Benzaldehyde
(c) Propionaldehyde and Acetaldehyde
(d) Benzaldehyde and Formaldehyde
Slide 60
28.
H3C
C
CH3
+ CH3 MgI
A
O
Here C is
(a) H3C
(c) H3C
H2 O
Ether
H+
Copper
B
300 oC
C
CH3
CH
CH2
CH2
CH2
OH
(b)
(d)
H3C
C
CH2
CH3 COOH
Slide 61
29. A compound gave a positive Tollen’s test. It also answered
haloform test. The compound was
(a) Ethanal
(c) Acetophenone
(b) Acetone
(d) Propanal
30. On reduction with LiAIH4, which of the following gives an
optically active compound?
(a) Propanal
(c) Butanol
(b) Propanone
(d) Butanone
Slide 62
31. Which of the following has highest boiling point ?
(a) Propanone
(c) Butanone
(b) 2-Pentanone
(d) 2-Hexanone
32. Benzaldehyde does not react with
(a) Tollen’s reagent
(c) 2,4-DNP solution
(b) Fehling solution
(d) NaHSO3
Slide 63
33. Which one of the following gives violet colour with neutral
Ferric Chloride solution?
(a) Acetaldehyde
(c) Salicylaldehyde
(b) Benzaldehyde
(d) Formaldehyde
34. Which one of the following is used to convert Benzaldehyde
into Toluene?
(a) LiAlH4
(c) Sodium and alcohol
(b) NaBH4
(d) Zn-Hg + Con. HCl Slide 64
35. A carbonyl compound reacts with hydrogen cyanide to form
cyanohydrin which on hydrolysis forms a racemic mixture of αhydroxy acids. The carbonyl compound is
(a) Diethyl ketone
(c) Formaldehyde
(b) Dimethyl ketone
(d) Acetaldehyde
Slide 65
36. Iodoform test is not given by
(a) Pentan-2-one
(c) Pentan-3-one
(b) Ethanol
(d) Ethanal
37. CH3CHO and C6H5CH2CHO can be distinguished by
(a) Benedict’s test
(c) Iodoform test
(b) Tollen’s reagent test
(d) Fehling’s reagent test
Slide 66
38. An aromatic compound X with molecular formula C9H10O gives
2,4-DNP test, Tollen;s test, undergoes Cannizaro reaction and on
vigarous oxidation gives 1,2-benzene dicarboxylic acid. X is
(a) 2-Methylacetophenone
(c) 2-Ethylbenzaldehyde
(b) 3-Ethylbenzaldehyde
(d) 3-Methylacetophenone
Slide 67
39. Aldol condensation between which of the following two
compounds followed by dehydration gives methyl vinyl ketone?
(a) Formaldehyde and acetone
(b) Formaldehyde and acetaldehyde
(c) Two molecules of acetaldehyde
(d) Two molecules of acetone
Slide 68
40. Which of the following reactions will not result in the formation
of carbon-carbon bonds?
(a) Friedel-Craft acylation
(b) Reimer- Tiemann reaction
(c) Wurtz reaction
(d) Cannizzaro reaction
Slide 69
41. Trichloroacetataldehyde is subjected to Cannizzaro’s reaction
by using NaOH. The mixture of the products contains sodium
trichloroacetate and another compound. The other compound is
(a) Trichloromethanol
(b) 2,2,2-Trichloropropanol
(c) Chloroform
(d) 2,2,2-Trichloroethanol
Slide 70
42. Consider the reaction:
RCHO+NH2NH2 → RCH=N-NH2
What sort of reaction is this?
(a) Electrophilic addition-elimination reaction
(b) Free radical addition-elimination reaction
(c) Electrophilic substitution-elimination reaction
(d) Nucleophilic addition-elimination reaction
Slide 71
43. Which of the following ketones cannot be prepared by
pyrolysis of a suitable calcium salt of a fatty acid?
(a) Benzophenone
(c) Butanone
(b) Pentan-3-one
(d) Propanone
44. Cyanohydrin of which of the following gives lactic acid on
hydrolysis?
(a) CH3COCH3
(c) C6H5CH2CHO
(b) HCHO
(d) CH3CHO
Slide 72
45. Which of the following reagents can help in separating a
mixture of acetone and isopropyl alcohol?
(a) NaOH
(b) NaCl
(c) NaHSO3
(d) NaHSO4
Slide 73
46. Arrange the following compounds in increasing order of their
reactivity in nucleophilic addition reactions; Ethanal(I),
Propanal(II), Propanone(III) and Butanone(IV).
(a) III<II<I<IV
(c) IV<III<II<I
(b) II<I<III<IV
(d) I<II<III<IV
Slide 74
47. Which of the following compounds does not react with sodium
bisulphate?
(a)Benzaldehyde
(c)Acetone
(b)Acetophenone
(d)Acetaldehyde
Slide 75
48. A compound A has molecular formula C2Cl3OH. It reduces
Fehling’s solution and on oxidation gives a monocarboxylic
acid B. A is obtained by the action of Cl2 on ethyl alcohol. A is
(a) Chloral
(c) Chloromethane
(b) Chloroform
(d) Chloroacetic acid
49. Acetone on distillation with conc. H2SO4 forms
(a) Phorone
(c)Mesitylene
(b) Acrolein
(d) Mesityl oxide
Slide 76
50. Compound A C5H10O forms a phenylhydrozone and gives negative
Tollen’s & iodoform test. On reduction it gives n-pentane. A is
(a) Pentanal
(c) Pentan-3-one
(b) Pentan-2-one
(d) Amyl alcohol
51. With which of the following reagents, carbonyl compound shows
addition cum elemination reaction?
(a) Carbonium ion
(c) HCN
(b) Brady’s reagent
(d) NaHSO3
Slide 77
52. Which one of the following is crotonaldehyde?
(a) CH2=CH-CHO
(c) CH3-CH=CH-CHO
(b) C6H5-CH=CH-CHO
(d) C6H5(OH)CHO
53. Which of the following will give negative test with Brady’
reagent?
(a)CH3CHO
(c) CH3-CO-CH3
(b) CH3-O-CH3
(d) C6H5CHO
Slide 78
54. The reaction of chloroform with acetone gives
(a) Mesityline
(c) Chloretone
(b) Ethylidene chloride
(d) Chloral
55. Hexamethylene tetramine is used as
(a) Analgesic
(c) Hypnotic
(b) Antipyrtic
(d) Urinary antiseptic
Slide 79
56. Reaction involving formation of trioxane from methanal is
called
(a) Aldol condensation
(b) Condensation polymerization
(c) Addition polymerzation
(d) Cannizzaro’s reaction
Slide 80
57. What is Stephan’s reaction?
(a) An alkyl isocyanide is reduced with Na/alcohol.
(b) An alkyl cyanide is reduced with LiAlH4.
(c) An alkanoyl chloride is reduced with Pd/BaSO4.
A
(d) An alkyl cyanide is reduced with SnCl2 and HCl.
Slide 81
58. Schiff’s reagent is:
(a) Magenta solution decolourised with chlorine.
(b) Ammonical cobalt chloride solution.
(c) Rosaniline hydrochloride decolourised with H2SO3.
(d) Cannizzaro’s reaction
Slide 82
59. Which of the following reactions is a condensation reaction?
(a) HCHO → Paraformaldehyde
(b) CH3COCH3 → Mesityl oxide
(c) CH3CHO → Paraldehyde
(d) H2C=CH2 → Polyethylene
Slide 83
60. In the following sequence of reaction, end product is
CaC2
H2O
A
Hg2+/H2SO4
B
[O]
C
Ca(OH)2/ heat
(a) Acetaldehyde
(b) Formaldehyde
(c) Acetic acid
(d) Acetone
D
Slide 84
Thank You.
Slide 85

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