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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

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•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

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Organic chemicals are universal

Organic

Chemicals

Biological matter

•Plants

•Animals

•Microbes

Geological matter

•Fossil Fuels

•Other

Atmospheric

and

cosmic matter

Manufactured

products

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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

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Organic chemicals in manufactured products

Bio-active

products

Medicines

Veterinary medicines

Herbicides

Pesticides

Fungicides

Plant growth

hormones

Medical imaging agents

Fertilizers

Antiseptics

Disinfectants

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Organic chemicals in manufactured products

Materials

Fibres & clothings

Plastics

Coatings & lacquers

Packaging

Paper

Films

Medical implants

Wound dressings

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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

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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

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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

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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

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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:

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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

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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)

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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,

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Hyperconjugation

Electrons in neighboring filled s orbital stabilize vacant

antibonding orbital – net positive interaction

Alkyl groups are better than H

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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

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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‟

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•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