CHAPTER 2: REACTIONS OF
ORGANIC COMPOUNDS
Section 2.1: Pg 57-64Section 2.2: Pg 65-79Section 2.3: Pg 81-95
1) Addition2) Substitution3) Elimination4) Oxidation5) Reduction6) Condensatio
n7) Hydrolysis
Types of Substitution Reactions
She called it a Blood Bath!
I wonder why she wrote it in Japanese
Look! I think she’s using it to blow her nose
Whew! That was easy!
MAIN TYPES OF REACTIONS in Organic Chem (not reactions to your last
test!)
1) ADDITION REACTION •Atoms added to a double or triple bond•Alkene or Alkyne undergoes addition reaction to break a double or triple bond•Example:
Reactant XY added to alkene makes alkaneTo recognize: Two reactants make 1 product
1) ADDITION REACTIONS
Common atoms that can be added to an alkene or alkyne
•H and OH (from H2O )
•H and X (from H-X) where X= Cl , Br, or I
•X and X from (X2) where X= Cl , Br, or I
•H and H (from H2)
EXAMPLES: Addition Reactions
1)
2)
ADDITION REACTIONS: ALKENES
•Symmetrical molecule reacts with asymmetrical molecule to give one product.
Symmetrical Asymmetrical
RULES FOR ADDITION• Two asymmetrical molecules
react to give two products.Example:
Which product is favoured ?
Asymmetrical
Asymmetrical
or+
Major product
Minor Product
2-bromobutane
1-bromobutane
“MARKOVNIKOV’S” Rule• "the rich get richer"• The carbon atom with the largest number of
carbon atoms gets the X (halogen) or OH bind to it
• Therefore 2- bromobutane is favoured
+
ADDITION REACTIONS: ALKYNES
• Also follow Markovnikov’s rule when asymmetrical
1,1,2,2-tetrabromopropane
Asymmetrical
ADDITION REACTIONS: ALKYNES
• May occur as two addition reactions:
+
+
2) SUBSTITUTION REACTION• A hydrogen atom or functional group is
replaced by a different functional group• To recognize: two compounds react to
form two products.
2-butanamine2-bromobutane
2) SUBSTITUTION REACTION
1) CH3CH2-OH + HI CH3CH2-I + H2O
2)
3)
ethanol iodoethane
SUBSTITUTION REACTIONAromatics
• Aromatics can only undergo substitution reactions
SUBSTITUTION REACTIONAlcohols
• Halogens in HCl, HBr or HI can substitute the OH group of alcohol or the reverse.
• For Ex: CH3-CH2-OH + HCl CH3-CH2Cl +
H2O
• The reverse reaction:CH3-CH2Cl + OH- CH3-CH2-OH + Cl-
(from water)
3) ELIMINATION REACTION• atoms are removed form a molecule to
form double bonds.• Reverse of addition• To recognize: One reactant breaks into
two products
ELIMINATION REACTION:Alcohol
• undergo elimination when heated in presence of strong acids, for example: H2SO4
Example:
ELIMINATION REACTION:Alkyl Halides
• Undergo elimination to produce alkenes
Bromoethane ethene hydrobromic acid
4) OXIDATION & 5) REDUCTION REACTIONS
• Change in the number of H or O atoms bonded to C
• Always occur together• One reactant is oxidized while the
other is reduced• For now, lets focus on reactant
only…
4) OXIDATION• Carbon atom forces more
bonds to Oxygen or less to Hydrogen
• For example: formation of C=O bond
• Occurs in presence of oxidizing agents [O] such as KMnO4, K2Cr2O7, and O3
• For now, focus on organic reactant only
4) OXIDATION: Alcohol
• Alcohol oxidation can form an aldehyde or ketone
Primary Alcohol
Secondary Alcohol
Tertiary Alcohols do not oxidize
4) OXIDATION: Aldehyde
• Aldehydes undergo oxidation to produce carboxylic acid
Example:
5) REDUCTION REACTION
• Carbon atom forms fewer bonds to Oxygen or more bonds to Hydrogen
• Aldehydes, ketones and carboxyliic acids can be “reduced” to alcohols
• Alkenes and alkynes can be reduced to become alkanes
• Occurs in the presence of reducing agents such as LiAlH4, and H2 where Hydrogen [H] is added
5) REDUCTION:Alkene
5) REDUCTION:Aldehyde/Ketone
6) CONDENSATION• two molecules combine to form a single, bigger
molecule. • Water is usually produced in this reaction • A carboxylic acid and alcohol can condense to
form an ester– called “ esterification”
• A carboxylic acid and amine can condense to form an amide
7) HYDROLYSIS• water adds to a bond splitting it into two • Reverse of a condensation reaction• Water can add to an ester or amide bond• Ester + water makes a carboxylic acid and
alcohol• Amide + water makes a carboxylic acid and
amine
1-propanol
POLYMERS
• very long molecules made by linking small molecules called monomers
• Example: -PET(Polyethylene terephthalate ) polymers
- Plastics are polymers that can be heated and moulded into specific shapes and forms
-Polyethene is made from monomer of
POLYMERS
can be synthetic or natural• Synthetic polymers
– man made polymer like plastics and polyester
• Natural polymers– found in nature like glucose
and silk
ADDITION Polymerization• Monomers added together through multiple
addition reactions• Examples:
• Examples Pg 83: Table 2.1
CONDENSATION Polymerization
• monomers are joined together by the formation of ester or amide bond
• Water created as a side product• Example:
• Polyesters contain many ester bonds• Nylon (polyamide) contains many amide bonds
HOMEWORK
• Page 63: 1-4• Page 64: 1-5• Page 67: 5-8• Page 73: 9-13• Page 78: 14-17 (See CONCEPT
Organizer)• Page 79: 1-8