This lecture series will cover:

1. Chemical bonds of carbon, hybridisation, spatial orientation, concept of functional groups.

2. Reactions and properties of alkanes, alkenes, haloalkanes, alkanols and amines, alkanones/alkanals, alkanoic acids esters/amides, and aromatic compounds
    

Alkanes are straight or branched chain hydrocarbons with only single covalent bonds between the carbon atoms. The general formula is CnH(2n+2) where n corresponds to the number of carbon atoms in the molecule. 

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Stereoisomers are isomers whose atoms are connected in the same order, but their spatial arrangement differs. These can be conformational, geometric or optical isomers. 

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A carbon compound is described as chiral if at least one carbon is bonded to four different atoms of groups. This carbon is a stereocentre. Enantiomers are pairs of chiral molecules. 

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Reactions of haloalkanes:

• Nucleophilic substitution

  • The SN1 mechanism is where the leaving group goes first and creates a carbocation which the nucleophile then joins. This is heterolytic dissociation
    
    
    
    
    
    
    
    
    
     

  • The SN2 mechanism is when the leaving group goes and the nucleophile joins at the same time. This is direct displacement
    
    
    
    
    
    
    
    
    
     

• Elimination - The nucleophile acts as a base to form an alkene

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Naming alkenes:

1. Select the longest continuous chain that contains the double bond

2. Name the parent compound as you would an alkane but change ending to ‘ene’

3. Number the carbon chain of parent starting at end nearer double bond

4. Use the smaller number to indicate position of the double bond

5. Branch chains and other groups are treated as in naming alkanes

 

Constitutional Isomers are compounds with the same molecular formula, but different bonding patterns and atomic organisation.

• Also called structural isomers

• Alkenes can form many constitutional isomers

 

Stereoisomers are compounds with the same molecular formula, molecular bonds are in the same place, only spatial arrangement differs.

• Geometric isomers are a specific type where atoms are connected in the same order but have spatially different arrangements

o   Cis-Trans isomers when each carbon is attached to two different groups

o   E-Z isomers when all four groups are different (sorted by atomic number)

 

Benzene is an aromatic compound (a cyclic hydrocarbon) with 6 electrons in pure p orbitals which overlap to create a delocalised ring of electrons above and below the carbon plane. 

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Reactions of benzene:

• Electrophilic substitution

• Specific types of electrophilic substitution are halogenation, nitration and sulfonation

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An alcohol has the functional group of a hydroxyl (-OH). When this is attached to an alkane it forms an alkanol. 

 

Reactions of alkanols:

• Oxidation

• Nucleophilic substitutions

• Elimination reactions to form an alkene and water