2) organic reactions 2.1- 2.3.ppt

7/27/2019 2) Organic Reactions 2.1- 2.3.ppt

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REACTIONS OFORGANIC

COMPOUNDS



1) Addition2) Substitution

3) Elimination

4) Oxidation5) Reduction

6) Condensation

7) Hydrolysis

Types of SubstitutionReactions

She called it

a Blood Bath!

I wonder whyshe wrote it in

Japanese

Look! I think

she’s using it to

blow her nose

Whew! That

was easy!

MAIN TYPES OF REACTIONS inOrganic Chem (not reactions to your last test!)



1) ADDITION REACTION•Atoms added to a double or triple bond

•Alkene or Alkyne undergoes addition reactionto break a double or triple bond

•Example:

Reactant XY added to alkene makes alkane

To recognize: Two reactants make 1 product



1) ADDITION REACTIONS

Common atoms that can be added toan 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 reactswith asymmetrical molecule togive one product.

Symmetrical Asymmetrical



RULES FOR ADDITION• Two asymmetrical molecules react to

give two products.Example:

Which product is favoured ?

Asymmetrical

Asymmetricalor

+



Major product

Minor Product

2-bromobutane

1-bromobutane

“MARKOVNIKOV’S” Rule• "the rich get richer"

• The carbon atom with the largest number ofcarbon atoms gets the X (halogen) or OH bind toit

• Therefore 2- bromobutane is favoured

+



ADDITION REACTIONS:ALKYNES

• Also follow Markovnikov’s rule whenasymmetrical

1,1,2,2-tetrabromopropaneAsymmetrical



ADDITION REACTIONS:ALKYNES

• May occur as two addition reactions:

+

+



2) SUBSTITUTION REACTION

• A hydrogen atom or functional group isreplaced by a different functional group

• To recognize: two compounds react to formtwo products.

2-butanamine2-bromobutane



2) SUBSTITUTION REACTION

1) CH3CH2-OH + HI CH3CH2-I + H2O

2)

3)

ethanol iodoethane



SUBSTITUTION REACTIONAromatics

• Aromatics can only undergo substitutionreactions



SUBSTITUTION REACTIONAlcohols

• Halogens in HCl, HBr or HI can substitutethe 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 presenceof 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 atomsbonded 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 forcesmore bonds to Oxygenor less to Hydrogen

• For example: formation

of C=O bond• Occurs in presence of

oxidizing agents [O]such as KMnO

4, K

2Cr

2O

7,

and O3

• For now, focus onorganic reactant only



4) OXIDATION:Alcohol

• Alcohol oxidation can form an aldehyde orketonePrimary Alcohol

Secondary Alcohol

Tertiary Alcohols do not oxidize



4) OXIDATION:Aldehyde

• Aldehydes undergo oxidation to producecarboxylic acid

Example:



5) REDUCTION REACTION

• Carbon atom forms fewer bonds toOxygen 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 whereHydrogen [H] is added



5) REDUCTION:Alkene



5) REDUCTION:Aldehyde/Ketone



6) CONDENSATION

• two molecules combine to form a single, biggermolecule.

• 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 anamide



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 moleculescalled monomers

• Example:

-PET(Polyethylene terephthalate ) polymers

- Plastics are polymers that can be heated and mouldedinto specific shapes and forms

-Polyethene is made from monomer of

http://upload.wikimedia.org/wikipedia/commons/5/5f/PET.png



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 multipleaddition reactions

• Examples:

• Examples Pg 83: Table 2.1

CONDENSATION



CONDENSATIONPolymerization

• monomers are joined together by the formation ofester 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

2) organic reactions 2.1- 2.3.ppt

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