definition a carbonyl group is a functional group found in organic compounds composed of a carbon...
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Carbonyl
Definition• a CARBONYL GROUP is a functional group found in organic compounds composed of a Carbon atom double - bonded to an oxygen atom.
═
C
O
Family Under CARBONYL GROUP
• Aldehyde• Ketone• Carboxylic Acid• Ester • Amide
Aldehyde
Definition• A compound containing a CARBONYL group bonded to a hydrogen.
Preparation
Natural Sources
O║ C – H
benzaldehyde
cinnamaldehyde
CH ═ CH – C – H
O ║
vanillin
O║ C – H
O – CH3
OH
Citral
CH3 – C = CH – CH2 –CH2 – C = CH – C – H
CH3 CH3
║O
Synthetic Sources
Oxidation 1ᵒ Alcohol gen.
formula 1ᵒ Alcohol ---→ Aldehyde + H2O
Hydration of Alkynes
Alkynes + H2O ---→ Aldehyde
gen. formula
Uses
Preservatives &
Indus. Solvent
Adhesive additives
Medicine &
Supplements
Food &
Sweets
Plastics
PhysicalProperti
es
uniqueness of Aldehyde• CARBONYL groups of aldehydes give them
sufficient POLARITY.• That makes their boiling points higher than
those of non – polar organic compounds.• But lower compares to alcohol• Because no HYDROGEN bonding occurs in
ALDEHYDES.
Table of ComparisonsClass Example Molecular
weightBoiling Point
Solubility in water
Alkane Butane 58 0 ᵒC InsolubleAldehyde Propanal 58 49 ᵒC SolubleAldehyde Butanal 72 76 ᵒC Soluble
Ketone Propanone 58 56 ᵒC Soluble
Therefore, boiling points of ALDEHYDES are lower than ketone and alcohol but higher compare to alkane.
Alcohol 2 - propanol 60 97 ᵒC SolubleAlcohol 1 - butanol 74 118 ᵒC Soluble
Nomenclature
IUPAC NAME COMMON NAME LATIN WORD GREEK ALPHABET
SYMBOL
(1) Methanal Formaldehyde (Formica) Ant Alpha α(2) Ethanal Acetaldehyde (Acetum) Vinegar Beta β(3) Propanal Propionaldehyde (Protus/Milk)(Pion/Fats ) Gamma γ(4) Butanal Butyraldehyde (Butyrum) Butter Delta δ(5) Pentanal Valeraldehyde Valerian Root Epsilon ε(6) Hexanal Caproaldehyde Goats Zeta ζ(7) Heptanal Enanthaldehyde (oenanthe) Vines Eta η(8) Octanal Caprylaldehayde Goats Theta Ө(9) Nonanal Pelargonaldehyde (an herb) Pelargonium Iota ι(10) Decanal Capraldehyde Goats Kappa κ
Things 2 remember
IUPAC RULES• IUPAC rule in naming ALDEHYDES follows the
usual pattern. • The longest chain carrying the ALDEHYDE
functional group is considered the parent structure and named by replacing the – e – of the corresponding ALKANE by – al – .
• The position of a substituent is indicated by number, the CARBONYL carbon always being considered as C – 1.
• Are derived from D’ names of the corresponding CARBOXYLIC ACIDS by replacing by replacing – ic – acid by ALDEHYDE.
• Branched chain ALDEHYDES are named as derivatives of straight – chain aldehydes.
• To indicate D’ point of attachment, the GREEK letters, α -, β -, γ -, δ -,ε -, ζ -, η -, θ -, ι -, κ, etc., are used;
• The α – carbon is the one bearing the ALDEHYDE group.
COMMON Naming
EXAMPLEs:
O ║H – C – H
methanal
formaldehyde
O ║CH3 – C – H
ethanal
acetaldehyde
EXAMPLEs:
CH3 – CH2 – CH2 – C – H
O║
butanal butyraldehyde
CH3 – (CH2)5 – C – H
O║
heptanal enanthaldehyde
EXAMPLE:
CH3 – C – CH2 – CH2 – C – C – H
CH3
CH3CH3
3HC O║
2,2,5,5 – tetramethylhexanal
α,α,δ,δ – tetramethylcaproaldehyde
EXAMPLE:
CH3 – CH2 – CH – CH2 – CH3
O ║C – H
2 – ethylbutanal
α– ethylbutyraldehyde
EXAMPLE:
CH3 – CH – C – CH2 – C – H
O║
OH
NO2
CH3
4 – hydroxy – 3 – methyl – 3 – nitropentanal
γ – hydroxy – β – methyl – β – nitrovaleraldehyde
EXAMPLE:
CH3 – (CH2)3 – C – C – (CH2)2 – C – H
O║
3HC CH3
CH2 – CH33HC – 2HC
4,5 – diethyl – 4,5 – dimethyl – nonanal
γ,δ – diethyl – γ,δ – dimethyl – pelargonaldehyde
EXAMPLE:
CH2 – C – C – C – C – C – H
O║
OH OHOH
H H
H
OH H
OH
2,3,4,5,6 – pentahydroxyhexanal
α,β,γ,δ,ε – hydroxycaproaldehyde
GLUCOSE
GLUCOSE
EXAMPLEs:
CH3 – CH ═ CH – CH2 – C – H
O║
3 – pentenal
CH3 – C = CH – CH2 –CH2 – C = CH – C – H
O║
CH3CH3
3,7 – dimethyl – 2,6 – octadienal
CITRAL
EXAMPLE:
CH3 – (CH2)3 – C – (CH2)4 – CH ═ CH2
O ║C – H
CH2
CH2 – CH3
3 – butyl – 3 – ethyl – 8 – nonenal
EXAMPLEs:
CH3 – C ≡ C – CH ═ CH – CH2 – C – H
O║
3 – heptenal – 5 – yne
CH2 – (CH2)3 – C ≡ C – CH – (CH2)2 – CH3
O ║C – H
Cl
8 – chloro – 2 – propyl – 3 – octynal
3 – ene – 5 – heptynal
3 – hepten – 5 – yne – al
EXAMPLEs: O ║ C – H
cyclohexanal
cyclohexanecarbaldehyde
O ║ C – H
HO
3 – hydroxycyclopentanal γ – hydroxycyclopentanecarbaldehyde
EXAMPLEs:
O ║ C – H
OH4 – hydroxy – 2 – cyclobutenal
δ – hydroxycyclobutenecarbaldehyde
O ║ C – H
2 – cyclopropynal
cyclopropynecarbaldehyde
EXAMPLEs: O ║ C – H
benzaldehyde O ║ C – H
NO2
3HC
3 – methyl – 5 – nitrobenzaldehyde
γ – methyl – ε - nitrobenzaldehyde
Chemical
Properties
ALDEHYDES undergoes
• Oxidation• Hydrogenation• Hemi & Acetal Formation• Hydrolysis
Oxidation of Aldehyde gen.
formula Aldehyde + (O) -----→ Carboxylic AcidKMnO4
K2Cr2O7
EXAMPLE: O ║CH3 – CH2 – C – H --------→
O ║CH3 – CH2 – C – OH
K2Cr2O7
propanal propanoic acid
Oxidation of AldehydeEXAMPLE:
O ║ C – H
--------------→ KMnO4
O ║ C – OH
benzaldehyde benzoic acid
Oxidation of AldehydeEXAMPLE:
O ║CH3 – CH2 – C – CH2 – C – H
CH2 – CH2 – CH3
CH3 – CH2
-------→ KMnO4
O ║CH3 – CH2 – C – CH2 – C – OH
CH2 – CH2 – CH3
CH3 – CH2
3,3 - diethylhexanal 3,3 – diethylhexanoic acid
Hydrogenation of Aldehyde
gen. formula Aldehyde + H2 -----→ Primary AlcoholPt/Ni
EXAMPLE:
O ║CH3 – (CH2)4 – C – H + H2 -----→
Pt/Ni
OH │CH3 – (CH2)4 – C – H │ H
H – H
hexanal hexanol
Hydrogenation of AldehydeEXAMPLE:
O ║CH3 – C – C – H
CH3
CH3
+ H2 -----→Pt/Ni
H – H OH │CH3 – C – C – H │ H
CH3
CH3
2,2 – dimethylpropanal 2,2 – dimethylpropanol
Hemi Formation gen.
formula Aldehyde + Alcohol ↔ Hemiacetal + Alcohol ↔ Acetal + H2OH+H+
EXAMPLE:
CH3 – C – H
O ║
+ H – O – CH3↔H+ CH3 – C – H
OH │
O – CH3
Hemi acetal
+ H – O – CH3
- Fin -