Post on 19-Jul-2016
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WELCOME TO THE WORLD OF ORGANIC CHEMISTRY!!!
WHAT IS ORGANIC CHEMISTRY? The study of carbon-containing compounds
- Organic-Inorganic
why is it so important?• Think about how organic compounds affect our daily life:
***OUR FOOD – CARBOHYDRATES, PROTEINS, TRIGLYCERIDES
SUCROSE PROTEIN
***OUR MEDICINES
C
OH
O
OHC
O
OH
OCOCH3
(CH3CO2)O
H2SO4
PARACETAMOLASPIRIN
***OUR CLOTHES – NATURAL AND SYNTHETIC FIBERS
***OILS, PERFUMES, PAINTS, PLASTICS, DETERGENTS, ETC.
ORGANIC COMPOUNDS
More than 5,000,000 known organic compounds compared to only about 200,000 to 300,000 known inorganic compounds.
General properties are different from inorganic compounds (ionic salts etc.)
Organic compounds
Covalent bonding Low melting
points Mainly insoluble
in water Mainly soluble in
organic solvents (e.g., gasoline)
Almost all burn Slower reactions
Inorganic compounds
Ionic bonding High melting
points Mainly soluble in
water Mainly insoluble in
organic solvents Very few burn Very fast reactions
COVALENT BONDING
A covalent bond involves sharing of a pair of electrons between two atoms
Each atom contributes one electron for sharing
The shared electrons are localised between the two atomic nuclei
COVALENT BONDING Example
H● + H× H H
H H can be represented as H—H
● ×
● ×
WHY CARBON?
A carbon atom forms four bonds
Carbon atoms form stable bonds with other carbon atoms (i.e., the C—C covalent bond is strong)
Can form chains and even networks.Examples: diamond and graphite
WHY CARBON?
• A carbon atom forms four bonds
• Graphite• Diamond
Examples: diamond and graphite
WHY CARBON?
Carbon atoms also form stable bonds with other atoms (i.e., C—H, C—O, C—N, C—Cl etc. bonds are strong).
Many combinations and arrangements are possible
EXAMPLES OF ORGANIC COMPOUNDS
HYDROCARBONS (CNHM)
Extracted from crude oil
Separated according to size for various purposes
Source of energy, plastics, solvents, raw materials, etc.
ETHANOL C2H5OH
C
H
H C
H
O
H
H
H
ASPIRIN (ACETYLSALICYLIC ACID)
C
OH
O
OHC
O
OH
OCOCH3
(CH3CO2)O
H2SO4
CHLOROFLUOROCARBONS(CFCS)
C
F
ClCl
Cl
CFCl3
WHAT ARE ORGANIC MOLECULES?
Main structure: carbon backbone Each carbon must have 4
covalent bonds (i.e., share an electron with a neighbouring atom)
building blocks attached to each other by covalent bonds
Functional groups with specific properties
EXAMPLES OF FUNCTIONAL GROUPS
Ester Alkene C=C Alcohol –OH Halogen groups –Cl, –Br Amine –NH2 Carboxylic acid –COOH Amide –CONH etc.
ESTERS
C OC
O
C
H
H
H
H
H
H
Methylacetate
ESTERSSynthesised when a carboxylic acidand an alcohol react
R C
O
O H R O H
C O
O
R R H2O
ESTERS
Structure FlavourBananaOrange
PineappleApple
Raspberry
CH3COOCH2CH2CH(CH3)2
CH3COO(CH2)7CH3
CH2(CH2)2COOCH2CH3
CH3(CH2)2COOCH3
HCOOCH2CH(CH3)2
Responsible for many flavours and fragrances.Generally sweet and pleasant smells.
ESTERS: OTHER APPLICATIONS
Aspirin, an analgesic (painkiller) Ethyl acetate, a solvent Polyesters---Clothing---Used to make synthetic arteries for
heart surgery---Bio-absorbable staples for surgery
THANK YOU