Chemistry 30 – Organic Chemistry - Part 2 To accompany Inquiry into Chemistry

Organic Chemistry – 15.1 – Types of Organic Reactions ACombustion Reactions We will focus on complete combustions: hydrocarbon + O 2 (g) CO 2 (g) + H 2 O(g) + energy Cellular respiration is a complete combustion (but H 2 O(l) is produced) Many hydrocarbon derivatives also undergo complete combustion

Organic Chemistry – 15.1 – Types of Organic Reactions Do questions 1a, 2, and 3, page 589

Organic Chemistry – 15.1 – Types of Organic Reactions BAddition Reactions Product has more bonds! Addition C = C + Y – Z - C – C - Y Z see page Addition can occur with alkene or alkyne: + water (HOH) alcohol + hydrogen (H 2 ) alkane + hydrogen halide (HX) alkyl halide + halogen (X 2 ) alkyl halide

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 CH 2 – O – C - R CH – O – C – R R′ = = = O O O H H H H A fat molecule: trans linkage cis linkage fats are triesters!

Organic Chemistry – 15.1 – Types of Organic Reactions CElimination Reactions Essentially the reverse of addition – less bonds Alcohols undergo elimination to produce water and an alkene Alkyl halides can undergo elimination to produce alkene and hydrogen halide C = C + Y – Z - C – C - Y Z Examples on page 593

Organic Chemistry – 15.1 – Types of Organic Reactions DSubstitution 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 - C – Y + A – Z - C – Z + A - Y

Organic Chemistry – 15.1 – Types of Organic Reactions Aromatics + halogens will undergo substitution, not addition

Organic Chemistry – 15.1 – Types of Organic Reactions EEsterification 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 H 2 SO 4 catalyst

Organic Chemistry – 15.1 – Types of Organic Reactions Example: CH 3 – CH 2 – C – O - H + H - O-CH 3 = O H 2 SO 4

Organic Chemistry – 15.1 – Types of Organic Reactions Example: = O CH 3 – CH 2 – C – O – CH 3 + HOH CH 3 – CH 2 – C – O - H + H - O-CH 3 = O H 2 SO 4 methyl propanoate I prefer to write it in reverse direction (alcohol 1 st ) to make naming ester easier CH 3 – O – H + H – O – C – CH 2 – CH 3 CH 3 – O – C – CH 2 – CH 3 + HOH = O = O H 2 SO 4 methyl propanoate now ester is written in order of name

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 Do Investigation 15.A, page 597

Organic Chemistry – 15.1 – Types of Organic Reactions Summary: Reaction type Complete Combustion AdditionEliminationSubstitutionEsteri- fication Reactants Hydrocarbon* + O 2 ene or yne + HOH, X 2, HX, or H 2 alcohol or alkyl halide alkane or aromatic + X 2 alcohol + carboxylic acid ProductsCO 2 (g) + H 2 O(g) or (l) alcohol, alkyl halide*, alkane alkene + HOH or HX alkyl halideester + water Othertriple or double to single single to double slow; needs uv light acid catalyst needed Othermore bonds*fewer bonds*

Organic Chemistry – 15.2 – Polymers and the Petrochemical Industry Bromine test for double bonds Bromine, Br 2, forms a brown solution (remember electrolysis of KBr(aq) If Br 2 (aq) is mixed with an alkene or alkyne, addition will occur and the brown colour will disappear in the aqueous layer If Br 2 (aq) is mixed with an alkane or aromatic, substitution (slow) will occur and the aqueous layer will remain brown…………..

Organic Chemistry – 15.1 – Types of Organic Reactions Read “Octane-Enhancing Compounds” page 599 and “Replacing CFC’s” page 600 Section 15.1 – oral review – question 1 - reaction type

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 Plastics are always synthetic, though not all polymers are synthetic

Organic Chemistry – 15.2 – Polymers and the Petrochemical Industry Addition polymerization the reaction is an addition reaction as studied earlier Example: polyethylene CH 2 =CH 2 + CH 2 =CH 2 -CH 2 -CH 2 -CH 2 -CH CH 2 =CH 2 - CH 2 – CH 2 – CH 2 – CH 2 – CH 2 – CH 2 – and on and on

Organic Chemistry – 15.2 – Polymers and the Petrochemical Industry Other addition polymers: Cl

Organic Chemistry – 15.2 – Polymers and the Petrochemical Industry Condensation polymerization – water produced polyesters and nylons polyester example: ester linkage

Organic Chemistry – 15.2 – Polymers and the Petrochemical Industry nylon example: amide linkage: same type of bond present between amino acids in proteins

Organic Chemistry – 15.2 – Polymers and the Petrochemical Industry Do Practice Problems page 606, questions 7-10

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: C 2 H 6 (g) CH 2 =CH 2 (g) + H 2 (g) ethane ethene Ethene is used to produce ethylene glycol (ethane-1,2-diol), polyethylene, and polyvinyl chloride Pt

Organic Chemistry – 15.2 – Polymers and the Petrochemical Industry Manufacture of PVC (polyvinyl chloride): Step 1: Step 2: C = C (g) + Cl 2 (g) - C – C - (g) Cl reaction type? Cl - C – C – (g) C = C (g) + HCl(g) Cl reaction type? HCl from step 2 reacted with more ethene to produce more Cl - C – C -

Organic Chemistry – 15.2 – Polymers and the Petrochemical Industry Step 3: Cl n C = C ………. - C – C – C – C – C – C - ………. Cl polyvinyl chloride

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 Cl C = C

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 Note: recycling is not the cure-all. Reducing and reusing are better solutions. Why?

Organic Chemistry – 15.2 – Polymers and the Petrochemical Industry Natural Polymers Carbohydrates: (monomer-glucose) cellulose, starch, glycogen Proteins: (monomer-amino acids) DNA

Organic Chemistry – 15.2 – Polymers and the Petrochemical Industry Section 15.2 Review, page 614, question 1-6

Organic Chemistry – 15.2 – Polymers and the Petrochemical Industry