Organic Chemistry

What is organic chemistry? All biological molecules – simple sugars to complex nucleic acids All fossil fuels – including oil, coal, and natural gas Most synthetic materials – nylon, Lycra, Gore- Tex Consumer products – paints, detergents, refrigerants

Define Organic Compound It is a compound that contains carbon and, in nearly all cases, also hydrogen in a covalently bonded structure

Why Carbon? Catenation, which is the ability for carbon to form bonds with other carbon atoms to form carbon chains and rings Carbon is able to form four strong covalent bonds with other carbon atoms

Classification The classification system is based on the structure and bonding species Functional groups, part of bonding species, are identifiers of the nature(chemical reaction) of the organic compound

Types of Reactants Saturated Unsaturated Aliphatic Arenes Electrophile Nucleophile

Saturated Compound that only contain single bonds – Ex: alkanes

Unsaturated Compounds which contain double or triple bonds – Ex: alkene, arenes

Aliphatics Compounds which do not contain a benzene ring – Alkanes, alkenes

Arenes Compounds which contain a benzene ring; all are unsaturated – Benzene, phenol

Electrophile (electron seeking) An electron-deficient species which therefore attracted to parts of molecules which are electron rich Electrophiles are positive ions or have partial positive charge Ex: NO 2 +, H +, Br δ+

Nucleophile (nucleus seeking) An electron rich species which is therefore attracted to parts of a molecules which are electron deficient Nucleophiles have a lone pair of electrons and may also have a negative charge – Ex: Cl -, OH -, NH 3

Types of Reactions Addition Substitution Elimination Addition-elimination

Addition Occurs when two reactants combine to form a single product Characteristic of unsaturated compounds – Ex: C 2 H 4 + Br 2 C 2 H 4 Br 2

Substitution Occurs when one atom or group of atoms in a compound is replaced by a different atom or group Characteristic of saturated compounds and aromatic compounds – Ex: CH 4 + Cl 2 CH 3 Cl + HCl

Elimination Occurs when a small molecule is lost from a larger compound Usually results in the formation of a double or triple bond When the molecule eliminated is H 2 O the reaction is dehydration – C 2 H 5 OH C 2 H 4 + H 2 O

Addition-elimination Occurs when two reactants join together (addition) and in the process a small molecule is lost (elimination) Reaction occurs between a functional group in each reactant This reaction may also be called condensation – RNH 2 + R’COOH R’CONHR + H 2 O

Types of bond breaking (bond fission) Homolytic fission Heterolytic fission

Homolytic fission When a covalent bond breaks by splitting the shared pair of electrons between the two products Produces two free radicals each with an unpaired electron

Heterolytic fission When covalent bond breaks with both the shared electrons going to one of the products Produces two oppositely charged ions

Review HL Book pages

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