1. TYPES OF ORGANIC CHEMICAL REACTIONS

2. Categories of Simple Organic Reactions
Substitution
Addition
Condensation/elimination
Hydrolysis
Mild oxidation & strong oxidation
Combustion
Acid/base reactions

3. Substitution Reactions
A substitution reaction occurs whenever one atom of an organic molecule is replaced by another. Substitution reactions often require heat and/or a catalyst in order to occur. Example: Substitution of an alkane H H H C H + Cl2 H C Cl + HCl H H

4. Substitution of Benzene
Due to the strong bonding arrangement between the carbon atoms in a benzene ring, the ring cannot be easily broken during chemical changes. The hydrogen atoms that are bonded to each carbon can be substituted for other atoms and groups.
Examples: H Br
+ HBr
+ Br2
+ HNO3
NO2
+ H2O
TNT synthesis…

5. Addition Reactions
In addition reactions, new atoms or groups are bonded to the atoms of an organic molecule. The organic molecule must be unsaturated to start with (double or triple bonds!)
New bonds can be made to the carbon atoms involved in the double or triple bond if the part of the bond is first broken.
I’m now ready to make more bonds! C H
CH2=CH2

6. Some Simple Addition Reactions
C=C H
+ H2 
H-C-C-H
(a.k.a. “hydrogenation”)
C=C H
+ HCl 
H-C-C-Cl
C=C H
+ H2O 
H-C-C-OH
(a.k.a. “hydrolysis”)

7. Markovnikov’s Rule
If the double or triple bond is part of a molecule with three or more carbon atoms in the chain, the most likely addition reaction products can be predicted using a rule first formulated by the Russian chemist V.V. Markovnikov.
Markovnikov’s Rule
…the more electronegative atom will predominantly bond to the carbon atom of the double bond that has fewer hydrogen atoms.

8. Markovnikov’s Rule º - Eg.1 H OH H C=C-CH3 + H2O  H- C - C- CH3 Eg.2
It should be mentioned that the primary alcohol (1-propanol) is also a possibility, but it would be produced in a much lower proportion than the 2-propanol shown above.
Eg.2
H-C C-CH2-CH3
+ 2HCl  - Cl H
Most favoured product!

9. Condensation/Elimination Reactions
Organic compounds containing hydroxyl or carboxyl groups can combine by eliminating a molecule of water between them.
An ether is created!
Example 1- condensation of two alcohols
H-C - C-O-H H
H-O-C - C-H H
H-C - C-O-C–C-H H
H2O +
Molecule of H2O is formed

10. Condensation/elimination
When an alcohol reacts with a carboxylic acid to eliminate a molecule of water between them, the resulting bond creates an ester linkage as shown below:
We’ve created an ester
H-C - C-O-H H O +
H-O-C – CH2-CH3
CH2-CH2- O- C-CH2-CH3 O
If excess water is added to an ester, the reaction will reverse itself. +
H2O

11. Uses of Esters
Demo!
Esters often have characteristic flavours and aromas which allows them to be used in food products.
Methanol + butanoic acid  methyl butanoate (apples)
Octanol + acetic acid  octyl acetate (orange)
Benzyl alcohol + butanoic acid  phenyl butanoate (flowers)
Pentanol + acetic acid  pentyl acetate

12. Condensation/elimination
If a molecule of water is eliminated from within a single molecule, an unsaturated compound is formed and the molecule is said to be “dehydrated.” H + H H H OH H
H2O

13. Oxidation Reactions
In the terminology of organic chemistry, when a molecule is oxidized, the number bonds to oxygen atoms increases within the molecule.
Oxidizing agents are varied: CrO3/H+, KMnO4, K2Cr2O7
Often, the oxidizing agent is represented simply as “O” over the reaction arrow:

14. Oxidation Reactions Mild Oxidation Strong Oxidation alcohol aldehyde H
CH3-C-OH H
CH3-C-H O
ethanal
ethanol
Strong Oxidation
alcohol
Carboxylic acid
CH3-C-OH H O
Ethanoic acid

15. Oxidation Reactions Strong Oxidation cont’d…
Secondary alcohols require a strong oxidizing agent and can only be oxidized to ketones.
CH3-C-CH2-CH3 H OH
2-butanol
CH3-C-CH2-CH3 O
butanone

16. Combustion
BOOM!
All organic compounds can be combusted or burned. Carbon dioxide gas and water vapour are the products of hydrocarbon combustion.
Combustion is really a type of very extreme oxidation reaction where O2(g) is the oxidizing agent.
2C2H2(g) + 5O2(g)  4CO2(g) + 2H2O(g)
CH3-CH2-OH(l) + 3O2(g)  2CO2(g) + 3H2O(g)