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 -