C30 organic part 2

Chemistry 30 – Organic

Chemistry - Part 2

To accompany

Organic Chemistry – 15.1 – Types of Organic Reactions

• A Combustion Reactions

• We will focus on complete combustions:

hydrocarbon + O₂(g) CO₂(g) + H₂O(g) + energy

• Cellular respiration is a complete combustion (but H₂O(l) is produced)

Organic Chemistry – 15.1 – Types of Organic Reactions

Organic Chemistry – 15.1 – Types of Organic Reactions

• B Addition Reactions

Product has more bonds! Addition

C = C + Y – Z - C – C -

Y Z

see page

Organic Chemistry – 15.1 – Types of Organic Reactions

• Your text has numerous

examples of addition reactions on page 590 and 591

• Read about trans fats on page 592

C = C C = C CH₂ – O – C - R

CH₂ – O – C - R CH – O – C – R R′ R′ = = = O O O H H H H

A fat molecule:

trans linkage

cis linkage

Organic Chemistry – 15.1 – Types of Organic Reactions

• C Elimination Reactions

• Essentially the reverse of addition – less

bonds

• Alcohols undergo elimination to produce water and an alkene

• Alkyl halides can undergo elimination to

C = C + Y – Z

- C – C - Y Z

Organic Chemistry – 15.1 – Types of Organic Reactions

• D Substitution Reactions

• Like name implies, something leaves and is replaced by something else

• Examples pages 593 and 594

• Note that for halogens + alkanes, reaction is very slow (essentially doesn’t occur) without presence of ultraviolet light

Organic Chemistry – 15.1 – Types of Organic Reactions

Organic Chemistry – 15.1 – Types of Organic Reactions

• E Esterification

• Esterification is a type of elimination reaction – water is produced

R - C – OH =

O

+ HO - R′ R - C – = O - R′

O

+ HOH

carboxylic

acid alcohol ester water

H₂SO₄

Organic Chemistry – 15.1 – Types of Organic Reactions

• Example:

CH₃ – CH₂ – C – O - H + H - O-CH= ₃

O _H

Organic Chemistry – 15.1 – Types of Organic Reactions

• Example:

=

O

CH₃ – CH₂ – C – O – CH₃ + HOH

CH₃ – CH₂ – C – O - H + H - = O-CH₃

O _H

2SO4

methyl propanoate

• I prefer to write it in reverse direction (alcohol 1st) to make naming ester easier

CH₃ – O – H + H – O – C – CH= ₂ – CH₃ CH₃ – O – C – CH₂ – CH₃ + HOH

O

=

O

H₂SO₄

methyl propanoate

Organic Chemistry – 15.1 – Types of Organic Reactions

• Further esterfication examples on page 595 – 6

• Other examples page 596

• Do Practice Problems 1 – 3, page 596 – 7

• Do WS 15.1.5

Organic Chemistry – 15.1 – Types of Organic Reactions • Summary: Reaction type Complete Combustion

Addition Elimination Substitution Esteri-fication Reactants Hydrocarbon*

+ O₂

ene or yne + HOH, X₂, HX, or H₂

alcohol or alkyl halide

alkane or aromatic + X₂

alcohol + carboxylic acid

Products CO₂(g) + H₂O(g) or (l)

alcohol, alkyl halide*,

alkane

alkene + HOH or HX

alkyl halide ester + water

Organic Chemistry – 15.2 – Polymers and the Petrochemical Industry

• Bromine test for double bonds

• Bromine, Br₂, forms a brown solution (remember

electrolysis of KBr(aq)

• If Br₂(aq) is mixed with an alkene or alkyne,

addition will occur and the brown colour will disappear in the aqueous layer

• If Br₂(aq) is mixed with an alkane or aromatic,

Organic Chemistry – 15.1 – Types of Organic Reactions

• Read “Octane-Enhancing Compounds” page 599 and

• “Replacing CFC’s” page 600

Organic Chemistry – 15.2 – Polymers and the Petrochemical Industry

• Polymer: a large long chain molecule with repeating units of small molecules called

monomers

• Plastics: polymers that can be heated and shaped into specific shapes and forms

Organic Chemistry – 15.2 – Polymers and the Petrochemical Industry

• Addition polymerization

the reaction is an addition reaction as studied earlier

• Example: polyethylene

CH₂=CH₂ + CH₂=CH₂ -CH₂-CH₂-CH₂-CH₂- + CH₂=CH₂

Organic Chemistry – 15.2 – Polymers and the Petrochemical Industry

• Other addition polymers:

2 2

2

2

2 2

Cl Cl

Organic Chemistry – 15.2 – Polymers and the Petrochemical Industry

• Condensation polymerization – water produced

• polyesters and nylons

• polyester example:

Organic Chemistry – 15.2 – Polymers and the Petrochemical Industry

• nylon example:

Organic Chemistry – 15.2 – Polymers and the Petrochemical Industry

Organic Chemistry – 15.2 – Polymers and the Petrochemical Industry

• Ethene (ethylene) is required for the manufacture of many substances in Alberta’s petrochemical industry

• Ethane, obtained from petroleum refining is

“cracked” to produce ethene by catalytic cracking: C₂H₆(g) CH₂=CH₂(g) + H₂(g)

ethane ethene

• Ethene is used to produce ethylene glycol (ethane-1,2-diol), polyethylene, and

polyvinyl chloride

Organic Chemistry – 15.2 – Polymers and the Petrochemical Industry

• Manufacture of PVC (polyvinyl chloride): Step 1:

• Step 2:

C = C (g) + Cl₂(g) - C – C - (g) Cl Cl

reaction type?

Cl Cl

- C – C – (g) C = C (g) + HCl(g) Cl

reaction type?

HCl from step 2 reacted with more ethene to produce more Cl Cl

-Organic Chemistry – 15.2 – Polymers and the Petrochemical Industry

• Step 3:

Cl

n C = C ………. - C – C – C – C – C – C - ……….

Cl Cl

Cl

Organic Chemistry – 15.2 – Polymers and the Petrochemical Industry

• Heath and Environmental Concerns:

• Vinyl chloride: was found in the 1970’s to be carcinogenic. Workers protected today by government legislation

• Manufacture and disposal of PVC may produce dioxins – highly toxic

Biggest source: people burning their own garbage

Organic Chemistry – 15.2 – Polymers and the Petrochemical Industry

• Plastics do not decay or rot – problems?

• Today: recycling programs – manufacture of useful products from recycled plastics

Organic Chemistry – 15.2 – Polymers and the Petrochemical Industry

• Natural Polymers

• Carbohydrates: (monomer-glucose) cellulose, starch, glycogen

• Proteins: (monomer-amino acids)

Organic Chemistry – 15.2 – Polymers and the Petrochemical Industry