Types of Organic Reactions Tom Nowak Cedar House School G12 Organic Chemistry

Organic Chemistry Reactions BOLD ONLY = examinable n Addition n Substitution n Combustion n Elimination n Esterification n Fermentation n Polymerization (Addition & Dehydration) n Saponification

Addition Addition reactions occur when atoms are added to an unsaturated molecule (an alkene or alkyne) + HH H H

Organic Chemistry Reactions n Addition 1) Define saturated and unsaturated, offer structural formula example of each 2) Explain why unsaturated must be the reactant

Substitution Substitution reactions occur when one type of atom replaces a hydrogen atom in a saturated (yet not necessary) molecule + + H Cl H-Cl

Organic Chemistry Reactions n Substitution Give your own example of substitution.

Combustion Combustion refers to the reaction of a compound with oxygen to produce energy (an exothermic reaction). There are two types: Complete combustion - in which CO2 is produced. Incomplete combustion - in which CO is produced. Water is also produced in combustion reactions Combustion is EXOTHERMIC turning chemical potential energy into heat energy

Example of complete combustion: CH O 2 CO H 2 O Example of incomplete combustion: 2 CH O 2 2 CO + 4 H 2 O In addition to the differences in the products, what other difference can you detect between complete and incomplete combustion?

The difference in the two types of combustion involves the ratio of oxygen to fuel : Complete Combustion: CH O 2 CO H 2 O The coefficients tell us that we need 2 oxygen molecules for every 1 methane molecule for complete combustion. Incomplete combustion: 2 CH O 2 2 CO + 4 H 2 O In incomplete combustion the ratio is 3 oxygens for every 2 methane molecules

Combustion final Explain why fossil fuels contain lots of Chemical potential energy Explain how fossil fuels release this potential energy With Combustion as thermal heat energy Explain how fossil fuel engine utilize this heat energy to Do work Explain how a larger volume engine (liters) is usually More ”powerful”

Elimination An elimination reaction occurs when 2 substituents or functional groups are REMOVED from a molecule. Elimination can be seen as the reverse of addition LG = leaving group, general term for substituent that is Usually Electron donating/negative (anion) or neutral For example = halides, oxides, other hydrocarbons H-C-C-LG  C=C + H-LG

Organic Chemistry Reactions n Elimination Describe elimination of alcohol Describe elimination of alkyl halide

Elimination: Dehydration of alcohol

Elimination: Dehydrohalogenation CH2Cl – CH2Cl  CH2=CHCl + HCl

Elimination: Cracking of hydrocarbons (thermal) = forms radicals &random products

Elimination: Cracking of hydrocarbons (catalytic) = more reliable carbon products

Esterification + + Acid Alcohol EsterWater 

Organic Chemistry Reactions n Esterification Write an equation to prepare an ester Identify the reactants from this product

Fermentation In the fermentation reaction a sugar is broken down into ethanol and carbon dioxide 2+2 GlucoseEthanol Carbon dioxide Xymase is an enzyme (a biological catalyst)

Polymerization is the process by which a number of small molecules (monomers) are hooked together to form a larger molecule (polymer). This is like forming a train from a bunch of individual railroad cars. Monomers Polymer

Addition Polymerization In this type of polymerization, the links between the monomers are formed by the breaking of double bonds. n EthenePolyethylene Addition polymerization always involves unsaturated compounds

Condensation Polymerization In this type of polymerization, two molecules react together to form a larger molecule plus some other product (sometimes water). n monomer Polymer In this case, the polymer is held together by ether linkages. + H 2 O

Organic Chemistry Reactions n Esterification n Addition n Substitution n Fermentation n Polymerization (Addition & Dehydration) n Saponification

Saponification In saponification, a fat reacts with a strong base to form glycerol and three soap molecules (long non-polar molecules with a polar end) + + Fat Strong base GlycerolSoap R - represents a long chain of C and H atoms