Alkane
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The aliphatic hydrocarbons which have carbon-carbon single bond are called alkane.
The general formula of alkane is CnH2n+2, where n = number of hydrogen
E.g. methane (CH4), ethane (C2H6) etc.
Word root Alkane Formula
C1 → Meth Methane CH4
C2 → Eth Ethane C2H6
C3 → Prop Propane C3H8
C4→ But Butane C4H10
C5 → Pent Pentane C5H12
C6 → Hex Hexane C6H14
C7 → Hept Heptane C7H16
C8 → Oct Octane C8H18
C9 → Non Nonane C9H20
C10 → Dec Decane C10H20
The suffix of the alkane is (ane).
Alkyl
The replacement or loss of one hydrogen from the alkane is called alkyl.
It is denoted by (-R), where –R indicates alkyl group.
The general formula of the alkyl is CnH2n+1.
Nomenclature
CH4 → methane
C2H6 → Ethane
CH3 - CH3 → Ethane
C3H8 → Propane
CH3 - CH2 - CH3 → n-propane
CH3 - CH2 - CH2 - CH2 - CH3 → n-pentane
IUPAC Nomenclature
Prefix + word root + primary suffix + secondary suffix
Prefix → 3-methyl
Word root → Hex
Primary suffix → ane
Therefore the IUPAC name is 3-methyl hexane
Prefix → 4- ethyl 4,6- methyl
Word root → Oct
Primary suffix → ane
Prefix
-CH3 → Methyl
-C2H5 → Ethyl
-Cl → Chloro
-Br → Bromo
-I → Iodo
-F → Fluoro
-CO → Keto
-CHO → Aldo
-NH2 → Amino
-OH → Hydroxyl
-CN → Cyano
-NO2 → Nitro
3-bromo 2, 4, 4 –trichloro 3-iodo 2-methyl hexane
Note:
R-X → alkyl halide or haloalkane
X = Cl, Br, I, F
CH3-Cl
Chloromethane Or Methyl Chloride
CH3-CH2-CH2-Br
Bromo Propane Or Propyl bromide
Isomerism
The organic compounds having same molecular formula but different structural formula are called isomers and the phenomenon is called isomerism.
From butane isomers, occur i.e. methane, ethane, propane does not have isomers.
E.g. pentane (C5H12)
Functional group
The structure of the particular family of an organic compound is called functional group.
It determines the properties of the organic compound.
|
S.n |
Class |
General formula |
Functional group |
Secondary suffix |
|
1 |
Hydrocarbon |
|||
|
a. |
Alkane |
CnH2n+2 |
||
|
b. |
Alkene |
CnH2n |
||
|
c. |
Alkyne |
CnH2n-2 |
||
|
2 |
Alkyl halide |
R-X |
-X |
|
|
3 |
Alcohol |
R-OH |
-OH |
Ol |
|
4 |
Ether |
R-O-R |
-O- |
ether |
|
5 |
Aldehyde |
R-COH |
-COH |
al |
|
6 |
Ketone |
R-CO-R |
-CO- |
one |
|
7 |
Carboxylic acid |
R-COOH |
-COOH |
oic acid |
|
8 |
Ester |
R-COO-R |
-COO- |
ester |
|
9 |
Amide |
R-CONH2 |
-CONH2 |
amide |
|
10 |
Amine |
R-NH2 |
-NH2 |
amine |
|
11 |
Cyanide |
R-CN |
-CN |
nitril |
Priority order: COOH > CHO > CO > OH
Alcohol
Structure: R - OH
Functional group: -OH
Secondary suffix: ol
Alkane – e + ol → alkanol
E.g. CH3 - CH = CH - CH2 - OH → but-2-ene-1-ol
CH3 - CH2 - CH2 - OH → Propanol
Aldehyde
Structure: R - CHO
Functional group: -CHO
Secondary suffix: al
Alkane – e + al → alkanol
E.g. CH3 - COH → Ethanal
CH3 - CH2 - COH → Propanal
H - CHO →Methanal
Note:
OCH3 → Methoxy
OC2H5 → Ethoxy
OC3H7 → Propoxy
Carboxylic acid
Structure: R - COOH
Functional group: -CHO
Secondary suffix: oic acid
Alkane – e + oic acid → alkanoic acid
E.g. H - COOH → Methanoic acid
CH3 - COOH → Ethanoic acid
CH3 - CH2 - COOH → Propanoic acid
CH3 - CH2 - CH2 - COOH →Butanoic acid
Ketone
Structure: R – COO - R
Functional group: -COO-
Secondary suffix: one
Alkane – e + one → alkanone
E.g.
→ Propane – e + one i.e propanone or propan – 2 – one
Amine
Structure: R - NH2
Functional group: -NH2
Secondary suffix: amine
Alkane – e + amine = alkanamine
E.g. CH3-NH2 → Methenamine
CH3 - CH2 - NH2 → Ethanamine
Ether
Structure: R - O - R
Functional group: - O -
Secondary suffix: Ether
E.g. CH3 - O - CH3 → dimethyl ether/methoxy methane
CH3 - CH2-O - CH3 →methoxy ethane
Cyanide
Structure: R - CN
Functional group: -CN
Secondary suffix: nitril
E.g. CH3 - CN →methyl cyanide/ethane nitril
CH3 - CH2 - CH2 - CN →butane nitril/propyl cyanide
Amide
Structure: R - CONH2
Functional group: -CONH2
Secondary suffix: amide
Alkane – e + amide = alkanamide
E.g.
O
‖
CH3 - C - NH2 → Ethanamide
