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113/09/2011
Senyawa organik, struktur dan reaksi
organik
What is Organic Chemistry?
It is defined as the study of hydrocarbons (compounds of hydrogen and carbon) and their derivatives
•Organic chemistry = Chemistry of carbon-based molecules
Organic molecules = Carbon-based molecules
30 million Organic Compounds
1.5 million Inorganic Compounds, 95%
Containing Carbon atom
Animal and plant matter, Foods, Pharmaceuticals, Cosmetics, Fertilizers, Plastics, Petrochemicals, Clothing
Why is it the element of life on earth?
•Has Four Bonding Electrons
•Unique Strong Covalent Bonds
•Strong Single, Double and Triple Bonds
Average Bond Energies (KJ mol-1)
C-C 607 Si-Si 230 C-H 416 Si-H 323
C-N 754 Si-N 470 C-O 336 Si-O 368
O-Si-O = Sand and Rocks
N-N 163 dan O-O 157
Why Carbon
413/09/2011
•Carbon: unique in its ability to catenate
[can form chains of atoms]
•Forms molecules composed of C-C bonds
CC
CC
CC
CC
CC
C
C
C
C
C
C C
CC
Linear molecules Branched molecules Cyclic molecules
Some properties of organic molecules
Stability: composed of stable C-C covalent bonds
•Defined molecular structures
•Defined three-dimensional shapes
513/09/2011
Organic chemicals are universal
Organic
Chemicals
Biological matter
•Plants
•Animals
•Microbes
Geological matter
•Fossil Fuels
•Other
Atmospheric
and
cosmic matter
Manufactured
products
613/09/2011
Biological organic chemicals Sugars
Proteins
Fats & oils
Vitamins
DNA & RNA
Wood
Natural rubber
Essential oils
Natural fibres
Antibiotics
Fermentation products
Natural flavours
Natural fragrances
Plant & microbial products
Bio-matter
713/09/2011
Organic chemicals in manufactured products
Bio-active
products
Medicines
Veterinary medicines
Herbicides
Pesticides
Fungicides
Plant growth
hormones
Medical imaging agents
Fertilizers
Antiseptics
Disinfectants
813/09/2011
Organic chemicals in manufactured products
Materials
Fibres & clothings
Plastics
Coatings & lacquers
Packaging
Paper
Films
Medical implants
Wound dressings
913/09/2011
Organic chemicals in manufactured products
FoodsSugars
Fats & Oils
Anti-oxidantsColourants
Flavourings
Vitamins
Dietary supplements
Fibre
Fuels
“Petrol”
“Diesel”
LPG
Natural gas
Coal
Peat/Turf
Methanol/Ethanol
1013/09/2011
Organic chemicals in manufactured
products
Miscellaneous Lubricants
Cosmetics
Fragrances
Pigments
Dyes
Inks
Adhesives
Explosives
Detergents
Surfactants
Emulsifiers
Coolants
Photographic agents
Anti-scalants
Forensic chemicals
Liquid crystal displays
H
CH H
H
methane
Carbon has 4 valence electrons
C
H
H
H
H
H C
Ne
Neon
Stable Octet required
Simplest Organic molecule
Covalent Bonding – Atoms Share Electrons
1213/09/2011
Covalent bonding
CCl4 - Covalent
C
Cl
Cl
Cl
Cl
HCl - Covalent
H Cl
MgF2 - Ionic
[ F ]2–[Mg]2+
H2O - Covalent
H O H
NH3 - Covalent
H N H
H
NaCl - Ionic
[ Cl ]–[Na] +
OH– - Covalent
O H
H2 - Covalent
H H
For more lessons, visit
www.chalkbored.com
C(6) - 1s2, 2s2, 2px1, 2py
1, 2pz0
lowest energy state
Hybridization
C(6) - 1s2, 2s1, 2px1, 2py
1, 2pz1
Excited state
4 sp3
2s 2px2py 2pz
+ + +
4 X sp3
Methane is Tetrahedral
109.50
Sp3 hybridized carbon
4 equivalent C-H bonds (s-bonds)
All purely single bonds are called s-bonds
H
CH
HH
1513/09/2011
Electrophile dan Nucleophile?
Electrophile “electron lover” abbreviated
E+ species that is attracted toward a
negative center. Electrophile is Lewis
acid, H+, ZnCl2, AlCl3
Nucleophile “nucleus lover” abbreviated
Nu:- species that is attracted to positive
center
1613/09/2011
Nucleophilicity and Basicity
Nucleophilicity is a measure of reagent‟s ability to cause a substitution reaction
H2O ROH Cl- Br - -OH -OR I- - CN
Increasing Nu: right
HO- + CH3CH2-Br CH3CH2OH + Br –
OH- acting as Nu:
1713/09/2011
Basicity is a measure a reagent‟s ability to accept
a proton in acid base reaction
I- Br - Cl- ROH H2O -CN -OH -OR
Increasing basicity: right
HO- + H-Cl H2O + Cl-
CH3CH-CH2 + -OH CH3CH=CH2
Br H
1813/09/2011
Background
Nucleophile - A Lewis Base with a pair of unshared electrons that seeks a positive part of an atom.
Electrophile - A Lewis Acid seeking an electron pair
Electrophilic Aromatic Substitution
(Bromination of Toluene)
1913/09/2011
Leaving group?
Gugus pergi/gugus lepas in term substitution
reaction
Halida ions are good leaving group because
they are very weak bases
Increase reactivity RF RCl RBr RI
F- is strong base than the other halida, poor
leaving group
-OH poor leaving group,
2013/09/2011
2113/09/2011
Hyperconjugation
Electrons in neighboring filled s orbital stabilize vacant
antibonding orbital – net positive interaction
Alkyl groups are better than H
2213/09/2011
Rotation of Bond Is Prohibitive
This prevents rotation about a carbon-carbon double bond (unlike a carbon-carbon single bond).
Creates possible alternative structures
Fractional distillation of crude oil
Petroleum Kerosene (C12-C16)
Bpt (200-250 ºC)
Heating oil (C15-C18)
Bpt (250-300 ºC)
Natural Gas (C1-C4)
Gasoline (C4-C12)
Bpt (40-200 ºC)
Straight-chain alkanes are a pure fuel, because of engine knock.
n-Heptane has an octane rating = 0
2,2,4-trimethylpentane has an octane rating = 100Catalytic cracking
2413/09/2011
Late 18th century:
•Compounds from living organisms - Organic
•Compounds from lifeless matter – Inorganic
•Organic compounds thought to have „vital force‟
Wöhler 1828
Ammonium cyanate UreaD
(Heat)
•Discredited concept of „vital force‟
2513/09/2011
•Lactic acid composed of Carbon, Hydrogen and Oxygen
•Fixed proportion: 1C:2H:1O
•Empirical formula: CH2O
•Majority of „organic‟ substances and many „inorganic‟
composed of Carbon, Hydrogen and maybe other elements
•Mid 19th Century: re-define organic substances
•Those composed of Carbon, Hydrogen (usually) and other
elements (maybe)
•1850-1860: Concept of Molecules
•Atoms of Carbon and other elements connected by covalent
bonds
•Hence, fixed proportions of elements
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